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32 results

signal.h

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  • master.c 66.80 KiB
    // SPDX-License-Identifier: GPL-2.0
    /*
     * Copyright (C) 2018 Cadence Design Systems Inc.
     *
     * Author: Boris Brezillon <boris.brezillon@bootlin.com>
     */
    
    #include <linux/atomic.h>
    #include <linux/bug.h>
    #include <linux/device.h>
    #include <linux/err.h>
    #include <linux/export.h>
    #include <linux/kernel.h>
    #include <linux/list.h>
    #include <linux/of.h>
    #include <linux/slab.h>
    #include <linux/spinlock.h>
    #include <linux/workqueue.h>
    
    #include "internals.h"
    
    static DEFINE_IDR(i3c_bus_idr);
    static DEFINE_MUTEX(i3c_core_lock);
    
    /**
     * i3c_bus_maintenance_lock - Lock the bus for a maintenance operation
     * @bus: I3C bus to take the lock on
     *
     * This function takes the bus lock so that no other operations can occur on
     * the bus. This is needed for all kind of bus maintenance operation, like
     * - enabling/disabling slave events
     * - re-triggering DAA
     * - changing the dynamic address of a device
     * - relinquishing mastership
     * - ...
     *
     * The reason for this kind of locking is that we don't want drivers and core
     * logic to rely on I3C device information that could be changed behind their
     * back.
     */
    static void i3c_bus_maintenance_lock(struct i3c_bus *bus)
    {
    	down_write(&bus->lock);
    }
    
    /**
     * i3c_bus_maintenance_unlock - Release the bus lock after a maintenance
     *			      operation
     * @bus: I3C bus to release the lock on
     *
     * Should be called when the bus maintenance operation is done. See
     * i3c_bus_maintenance_lock() for more details on what these maintenance
     * operations are.
     */
    static void i3c_bus_maintenance_unlock(struct i3c_bus *bus)
    {
    	up_write(&bus->lock);
    }
    
    /**
     * i3c_bus_normaluse_lock - Lock the bus for a normal operation
     * @bus: I3C bus to take the lock on
     *
     * This function takes the bus lock for any operation that is not a maintenance
     * operation (see i3c_bus_maintenance_lock() for a non-exhaustive list of
     * maintenance operations). Basically all communications with I3C devices are
     * normal operations (HDR, SDR transfers or CCC commands that do not change bus
     * state or I3C dynamic address).
     *
     * Note that this lock is not guaranteeing serialization of normal operations.
     * In other words, transfer requests passed to the I3C master can be submitted
     * in parallel and I3C master drivers have to use their own locking to make
     * sure two different communications are not inter-mixed, or access to the
     * output/input queue is not done while the engine is busy.
     */
    void i3c_bus_normaluse_lock(struct i3c_bus *bus)
    {
    	down_read(&bus->lock);
    }
    
    /**
     * i3c_bus_normaluse_unlock - Release the bus lock after a normal operation
     * @bus: I3C bus to release the lock on
     *
     * Should be called when a normal operation is done. See
     * i3c_bus_normaluse_lock() for more details on what these normal operations
     * are.
     */
    void i3c_bus_normaluse_unlock(struct i3c_bus *bus)
    {
    	up_read(&bus->lock);
    }
    
    static struct i3c_master_controller *
    i3c_bus_to_i3c_master(struct i3c_bus *i3cbus)
    {
    	return container_of(i3cbus, struct i3c_master_controller, bus);
    }
    
    static struct i3c_master_controller *dev_to_i3cmaster(struct device *dev)
    {
    	return container_of(dev, struct i3c_master_controller, dev);
    }
    
    static const struct device_type i3c_device_type;
    
    static struct i3c_bus *dev_to_i3cbus(struct device *dev)
    {
    	struct i3c_master_controller *master;
    
    	if (dev->type == &i3c_device_type)
    		return dev_to_i3cdev(dev)->bus;
    
    	master = dev_to_i3cmaster(dev);
    
    	return &master->bus;
    }
    
    static struct i3c_dev_desc *dev_to_i3cdesc(struct device *dev)
    {
    	struct i3c_master_controller *master;
    
    	if (dev->type == &i3c_device_type)
    		return dev_to_i3cdev(dev)->desc;
    
    	master = dev_to_i3cmaster(dev);
    
    	return master->this;
    }
    
    static ssize_t bcr_show(struct device *dev,
    			struct device_attribute *da,
    			char *buf)
    {
    	struct i3c_bus *bus = dev_to_i3cbus(dev);
    	struct i3c_dev_desc *desc;
    	ssize_t ret;
    
    	i3c_bus_normaluse_lock(bus);
    	desc = dev_to_i3cdesc(dev);
    	ret = sprintf(buf, "%x\n", desc->info.bcr);
    	i3c_bus_normaluse_unlock(bus);
    
    	return ret;
    }
    static DEVICE_ATTR_RO(bcr);
    
    static ssize_t dcr_show(struct device *dev,
    			struct device_attribute *da,
    			char *buf)
    {
    	struct i3c_bus *bus = dev_to_i3cbus(dev);
    	struct i3c_dev_desc *desc;
    	ssize_t ret;
    
    	i3c_bus_normaluse_lock(bus);
    	desc = dev_to_i3cdesc(dev);
    	ret = sprintf(buf, "%x\n", desc->info.dcr);
    	i3c_bus_normaluse_unlock(bus);
    
    	return ret;
    }
    static DEVICE_ATTR_RO(dcr);
    
    static ssize_t pid_show(struct device *dev,
    			struct device_attribute *da,
    			char *buf)
    {
    	struct i3c_bus *bus = dev_to_i3cbus(dev);
    	struct i3c_dev_desc *desc;
    	ssize_t ret;
    
    	i3c_bus_normaluse_lock(bus);
    	desc = dev_to_i3cdesc(dev);
    	ret = sprintf(buf, "%llx\n", desc->info.pid);
    	i3c_bus_normaluse_unlock(bus);
    
    	return ret;
    }
    static DEVICE_ATTR_RO(pid);
    
    static ssize_t dynamic_address_show(struct device *dev,
    				    struct device_attribute *da,
    				    char *buf)
    {
    	struct i3c_bus *bus = dev_to_i3cbus(dev);
    	struct i3c_dev_desc *desc;
    	ssize_t ret;
    
    	i3c_bus_normaluse_lock(bus);
    	desc = dev_to_i3cdesc(dev);
    	ret = sprintf(buf, "%02x\n", desc->info.dyn_addr);
    	i3c_bus_normaluse_unlock(bus);
    
    	return ret;
    }
    static DEVICE_ATTR_RO(dynamic_address);
    
    static const char * const hdrcap_strings[] = {
    	"hdr-ddr", "hdr-tsp", "hdr-tsl",
    };
    
    static ssize_t hdrcap_show(struct device *dev,
    			   struct device_attribute *da,
    			   char *buf)
    {
    	struct i3c_bus *bus = dev_to_i3cbus(dev);
    	struct i3c_dev_desc *desc;
    	ssize_t offset = 0, ret;
    	unsigned long caps;
    	int mode;
    
    	i3c_bus_normaluse_lock(bus);
    	desc = dev_to_i3cdesc(dev);
    	caps = desc->info.hdr_cap;
    	for_each_set_bit(mode, &caps, 8) {
    		if (mode >= ARRAY_SIZE(hdrcap_strings))
    			break;
    
    		if (!hdrcap_strings[mode])
    			continue;
    
    		ret = sprintf(buf + offset, offset ? " %s" : "%s",
    			      hdrcap_strings[mode]);
    		if (ret < 0)
    			goto out;
    
    		offset += ret;
    	}
    
    	ret = sprintf(buf + offset, "\n");
    	if (ret < 0)
    		goto out;
    
    	ret = offset + ret;
    
    out:
    	i3c_bus_normaluse_unlock(bus);
    
    	return ret;
    }
    static DEVICE_ATTR_RO(hdrcap);
    
    static ssize_t modalias_show(struct device *dev,
    			     struct device_attribute *da, char *buf)
    {
    	struct i3c_device *i3c = dev_to_i3cdev(dev);
    	struct i3c_device_info devinfo;
    	u16 manuf, part, ext;
    
    	i3c_device_get_info(i3c, &devinfo);
    	manuf = I3C_PID_MANUF_ID(devinfo.pid);
    	part = I3C_PID_PART_ID(devinfo.pid);
    	ext = I3C_PID_EXTRA_INFO(devinfo.pid);
    
    	if (I3C_PID_RND_LOWER_32BITS(devinfo.pid))
    		return sprintf(buf, "i3c:dcr%02Xmanuf%04X", devinfo.dcr,
    			       manuf);
    
    	return sprintf(buf, "i3c:dcr%02Xmanuf%04Xpart%04Xext%04X",
    		       devinfo.dcr, manuf, part, ext);
    }
    static DEVICE_ATTR_RO(modalias);
    
    static struct attribute *i3c_device_attrs[] = {
    	&dev_attr_bcr.attr,
    	&dev_attr_dcr.attr,
    	&dev_attr_pid.attr,
    	&dev_attr_dynamic_address.attr,
    	&dev_attr_hdrcap.attr,
    	&dev_attr_modalias.attr,
    	NULL,
    };
    ATTRIBUTE_GROUPS(i3c_device);
    
    static int i3c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
    {
    	struct i3c_device *i3cdev = dev_to_i3cdev(dev);
    	struct i3c_device_info devinfo;
    	u16 manuf, part, ext;
    
    	i3c_device_get_info(i3cdev, &devinfo);
    	manuf = I3C_PID_MANUF_ID(devinfo.pid);
    	part = I3C_PID_PART_ID(devinfo.pid);
    	ext = I3C_PID_EXTRA_INFO(devinfo.pid);
    
    	if (I3C_PID_RND_LOWER_32BITS(devinfo.pid))
    		return add_uevent_var(env, "MODALIAS=i3c:dcr%02Xmanuf%04X",
    				      devinfo.dcr, manuf);
    
    	return add_uevent_var(env,
    			      "MODALIAS=i3c:dcr%02Xmanuf%04Xpart%04Xext%04X",
    			      devinfo.dcr, manuf, part, ext);
    }
    
    static const struct device_type i3c_device_type = {
    	.groups	= i3c_device_groups,
    	.uevent = i3c_device_uevent,
    };
    
    static int i3c_device_match(struct device *dev, struct device_driver *drv)
    {
    	struct i3c_device *i3cdev;
    	struct i3c_driver *i3cdrv;
    
    	if (dev->type != &i3c_device_type)
    		return 0;
    
    	i3cdev = dev_to_i3cdev(dev);
    	i3cdrv = drv_to_i3cdrv(drv);
    	if (i3c_device_match_id(i3cdev, i3cdrv->id_table))
    		return 1;
    
    	return 0;
    }
    
    static int i3c_device_probe(struct device *dev)
    {
    	struct i3c_device *i3cdev = dev_to_i3cdev(dev);
    	struct i3c_driver *driver = drv_to_i3cdrv(dev->driver);
    
    	return driver->probe(i3cdev);
    }
    
    static int i3c_device_remove(struct device *dev)
    {
    	struct i3c_device *i3cdev = dev_to_i3cdev(dev);
    	struct i3c_driver *driver = drv_to_i3cdrv(dev->driver);
    
    	if (driver->remove)
    		driver->remove(i3cdev);
    
    	i3c_device_free_ibi(i3cdev);
    
    	return 0;
    }
    
    struct bus_type i3c_bus_type = {
    	.name = "i3c",
    	.match = i3c_device_match,
    	.probe = i3c_device_probe,
    	.remove = i3c_device_remove,
    };
    
    static enum i3c_addr_slot_status
    i3c_bus_get_addr_slot_status(struct i3c_bus *bus, u16 addr)
    {
    	int status, bitpos = addr * 2;
    
    	if (addr > I2C_MAX_ADDR)
    		return I3C_ADDR_SLOT_RSVD;
    
    	status = bus->addrslots[bitpos / BITS_PER_LONG];
    	status >>= bitpos % BITS_PER_LONG;
    
    	return status & I3C_ADDR_SLOT_STATUS_MASK;
    }
    
    static void i3c_bus_set_addr_slot_status(struct i3c_bus *bus, u16 addr,
    					 enum i3c_addr_slot_status status)
    {
    	int bitpos = addr * 2;
    	unsigned long *ptr;
    
    	if (addr > I2C_MAX_ADDR)
    		return;
    
    	ptr = bus->addrslots + (bitpos / BITS_PER_LONG);
    	*ptr &= ~((unsigned long)I3C_ADDR_SLOT_STATUS_MASK <<
    						(bitpos % BITS_PER_LONG));
    	*ptr |= (unsigned long)status << (bitpos % BITS_PER_LONG);
    }
    
    static bool i3c_bus_dev_addr_is_avail(struct i3c_bus *bus, u8 addr)
    {
    	enum i3c_addr_slot_status status;
    
    	status = i3c_bus_get_addr_slot_status(bus, addr);
    
    	return status == I3C_ADDR_SLOT_FREE;
    }
    
    static int i3c_bus_get_free_addr(struct i3c_bus *bus, u8 start_addr)
    {
    	enum i3c_addr_slot_status status;
    	u8 addr;
    
    	for (addr = start_addr; addr < I3C_MAX_ADDR; addr++) {
    		status = i3c_bus_get_addr_slot_status(bus, addr);
    		if (status == I3C_ADDR_SLOT_FREE)
    			return addr;
    	}
    
    	return -ENOMEM;
    }
    
    static void i3c_bus_init_addrslots(struct i3c_bus *bus)
    {
    	int i;
    
    	/* Addresses 0 to 7 are reserved. */
    	for (i = 0; i < 8; i++)
    		i3c_bus_set_addr_slot_status(bus, i, I3C_ADDR_SLOT_RSVD);
    
    	/*
    	 * Reserve broadcast address and all addresses that might collide
    	 * with the broadcast address when facing a single bit error.
    	 */
    	i3c_bus_set_addr_slot_status(bus, I3C_BROADCAST_ADDR,
    				     I3C_ADDR_SLOT_RSVD);
    	for (i = 0; i < 7; i++)
    		i3c_bus_set_addr_slot_status(bus, I3C_BROADCAST_ADDR ^ BIT(i),
    					     I3C_ADDR_SLOT_RSVD);
    }
    
    static void i3c_bus_cleanup(struct i3c_bus *i3cbus)
    {
    	mutex_lock(&i3c_core_lock);
    	idr_remove(&i3c_bus_idr, i3cbus->id);
    	mutex_unlock(&i3c_core_lock);
    }
    
    static int i3c_bus_init(struct i3c_bus *i3cbus)
    {
    	int ret;
    
    	init_rwsem(&i3cbus->lock);
    	INIT_LIST_HEAD(&i3cbus->devs.i2c);
    	INIT_LIST_HEAD(&i3cbus->devs.i3c);
    	i3c_bus_init_addrslots(i3cbus);
    	i3cbus->mode = I3C_BUS_MODE_PURE;
    
    	mutex_lock(&i3c_core_lock);
    	ret = idr_alloc(&i3c_bus_idr, i3cbus, 0, 0, GFP_KERNEL);
    	mutex_unlock(&i3c_core_lock);
    
    	if (ret < 0)
    		return ret;
    
    	i3cbus->id = ret;
    
    	return 0;
    }
    
    static const char * const i3c_bus_mode_strings[] = {
    	[I3C_BUS_MODE_PURE] = "pure",
    	[I3C_BUS_MODE_MIXED_FAST] = "mixed-fast",
    	[I3C_BUS_MODE_MIXED_LIMITED] = "mixed-limited",
    	[I3C_BUS_MODE_MIXED_SLOW] = "mixed-slow",
    };
    
    static ssize_t mode_show(struct device *dev,
    			 struct device_attribute *da,
    			 char *buf)
    {
    	struct i3c_bus *i3cbus = dev_to_i3cbus(dev);
    	ssize_t ret;
    
    	i3c_bus_normaluse_lock(i3cbus);
    	if (i3cbus->mode < 0 ||
    	    i3cbus->mode >= ARRAY_SIZE(i3c_bus_mode_strings) ||
    	    !i3c_bus_mode_strings[i3cbus->mode])
    		ret = sprintf(buf, "unknown\n");
    	else
    		ret = sprintf(buf, "%s\n", i3c_bus_mode_strings[i3cbus->mode]);
    	i3c_bus_normaluse_unlock(i3cbus);
    
    	return ret;
    }
    static DEVICE_ATTR_RO(mode);
    
    static ssize_t current_master_show(struct device *dev,
    				   struct device_attribute *da,
    				   char *buf)
    {
    	struct i3c_bus *i3cbus = dev_to_i3cbus(dev);
    	ssize_t ret;
    
    	i3c_bus_normaluse_lock(i3cbus);
    	ret = sprintf(buf, "%d-%llx\n", i3cbus->id,
    		      i3cbus->cur_master->info.pid);
    	i3c_bus_normaluse_unlock(i3cbus);
    
    	return ret;
    }
    static DEVICE_ATTR_RO(current_master);
    
    static ssize_t i3c_scl_frequency_show(struct device *dev,
    				      struct device_attribute *da,
    				      char *buf)
    {
    	struct i3c_bus *i3cbus = dev_to_i3cbus(dev);
    	ssize_t ret;
    
    	i3c_bus_normaluse_lock(i3cbus);
    	ret = sprintf(buf, "%ld\n", i3cbus->scl_rate.i3c);
    	i3c_bus_normaluse_unlock(i3cbus);
    
    	return ret;
    }
    static DEVICE_ATTR_RO(i3c_scl_frequency);
    
    static ssize_t i2c_scl_frequency_show(struct device *dev,
    				      struct device_attribute *da,
    				      char *buf)
    {
    	struct i3c_bus *i3cbus = dev_to_i3cbus(dev);
    	ssize_t ret;
    
    	i3c_bus_normaluse_lock(i3cbus);
    	ret = sprintf(buf, "%ld\n", i3cbus->scl_rate.i2c);
    	i3c_bus_normaluse_unlock(i3cbus);
    
    	return ret;
    }
    static DEVICE_ATTR_RO(i2c_scl_frequency);
    
    static struct attribute *i3c_masterdev_attrs[] = {
    	&dev_attr_mode.attr,
    	&dev_attr_current_master.attr,
    	&dev_attr_i3c_scl_frequency.attr,
    	&dev_attr_i2c_scl_frequency.attr,
    	&dev_attr_bcr.attr,
    	&dev_attr_dcr.attr,
    	&dev_attr_pid.attr,
    	&dev_attr_dynamic_address.attr,
    	&dev_attr_hdrcap.attr,
    	NULL,
    };
    ATTRIBUTE_GROUPS(i3c_masterdev);
    
    static void i3c_masterdev_release(struct device *dev)
    {
    	struct i3c_master_controller *master = dev_to_i3cmaster(dev);
    	struct i3c_bus *bus = dev_to_i3cbus(dev);
    
    	if (master->wq)
    		destroy_workqueue(master->wq);
    
    	WARN_ON(!list_empty(&bus->devs.i2c) || !list_empty(&bus->devs.i3c));
    	i3c_bus_cleanup(bus);
    
    	of_node_put(dev->of_node);
    }
    
    static const struct device_type i3c_masterdev_type = {
    	.groups	= i3c_masterdev_groups,
    };
    
    static int i3c_bus_set_mode(struct i3c_bus *i3cbus, enum i3c_bus_mode mode,
    			    unsigned long max_i2c_scl_rate)
    {
    	struct i3c_master_controller *master = i3c_bus_to_i3c_master(i3cbus);
    
    	i3cbus->mode = mode;
    
    	switch (i3cbus->mode) {
    	case I3C_BUS_MODE_PURE:
    		if (!i3cbus->scl_rate.i3c)
    			i3cbus->scl_rate.i3c = I3C_BUS_TYP_I3C_SCL_RATE;
    		break;
    	case I3C_BUS_MODE_MIXED_FAST:
    	case I3C_BUS_MODE_MIXED_LIMITED:
    		if (!i3cbus->scl_rate.i3c)
    			i3cbus->scl_rate.i3c = I3C_BUS_TYP_I3C_SCL_RATE;
    		if (!i3cbus->scl_rate.i2c)
    			i3cbus->scl_rate.i2c = max_i2c_scl_rate;
    		break;
    	case I3C_BUS_MODE_MIXED_SLOW:
    		if (!i3cbus->scl_rate.i2c)
    			i3cbus->scl_rate.i2c = max_i2c_scl_rate;
    		if (!i3cbus->scl_rate.i3c ||
    		    i3cbus->scl_rate.i3c > i3cbus->scl_rate.i2c)
    			i3cbus->scl_rate.i3c = i3cbus->scl_rate.i2c;
    		break;
    	default:
    		return -EINVAL;
    	}
    
    	dev_dbg(&master->dev, "i2c-scl = %ld Hz i3c-scl = %ld Hz\n",
    		i3cbus->scl_rate.i2c, i3cbus->scl_rate.i3c);
    
    	/*
    	 * I3C/I2C frequency may have been overridden, check that user-provided
    	 * values are not exceeding max possible frequency.
    	 */
    	if (i3cbus->scl_rate.i3c > I3C_BUS_MAX_I3C_SCL_RATE ||
    	    i3cbus->scl_rate.i2c > I3C_BUS_I2C_FM_PLUS_SCL_RATE)
    		return -EINVAL;
    
    	return 0;
    }
    
    static struct i3c_master_controller *
    i2c_adapter_to_i3c_master(struct i2c_adapter *adap)
    {
    	return container_of(adap, struct i3c_master_controller, i2c);
    }
    
    static struct i2c_adapter *
    i3c_master_to_i2c_adapter(struct i3c_master_controller *master)
    {
    	return &master->i2c;
    }
    
    static void i3c_master_free_i2c_dev(struct i2c_dev_desc *dev)
    {
    	kfree(dev);
    }
    
    static struct i2c_dev_desc *
    i3c_master_alloc_i2c_dev(struct i3c_master_controller *master,
    			 const struct i2c_dev_boardinfo *boardinfo)
    {
    	struct i2c_dev_desc *dev;
    
    	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
    	if (!dev)
    		return ERR_PTR(-ENOMEM);
    
    	dev->common.master = master;
    	dev->boardinfo = boardinfo;
    	dev->addr = boardinfo->base.addr;
    	dev->lvr = boardinfo->lvr;
    
    	return dev;
    }
    
    static void *i3c_ccc_cmd_dest_init(struct i3c_ccc_cmd_dest *dest, u8 addr,
    				   u16 payloadlen)
    {
    	dest->addr = addr;
    	dest->payload.len = payloadlen;
    	if (payloadlen)
    		dest->payload.data = kzalloc(payloadlen, GFP_KERNEL);
    	else
    		dest->payload.data = NULL;
    
    	return dest->payload.data;
    }
    
    static void i3c_ccc_cmd_dest_cleanup(struct i3c_ccc_cmd_dest *dest)
    {
    	kfree(dest->payload.data);
    }
    
    static void i3c_ccc_cmd_init(struct i3c_ccc_cmd *cmd, bool rnw, u8 id,
    			     struct i3c_ccc_cmd_dest *dests,
    			     unsigned int ndests)
    {
    	cmd->rnw = rnw ? 1 : 0;
    	cmd->id = id;
    	cmd->dests = dests;
    	cmd->ndests = ndests;
    	cmd->err = I3C_ERROR_UNKNOWN;
    }
    
    static int i3c_master_send_ccc_cmd_locked(struct i3c_master_controller *master,
    					  struct i3c_ccc_cmd *cmd)
    {
    	int ret;
    
    	if (!cmd || !master)
    		return -EINVAL;
    
    	if (WARN_ON(master->init_done &&
    		    !rwsem_is_locked(&master->bus.lock)))
    		return -EINVAL;
    
    	if (!master->ops->send_ccc_cmd)
    		return -ENOTSUPP;
    
    	if ((cmd->id & I3C_CCC_DIRECT) && (!cmd->dests || !cmd->ndests))
    		return -EINVAL;
    
    	if (master->ops->supports_ccc_cmd &&
    	    !master->ops->supports_ccc_cmd(master, cmd))
    		return -ENOTSUPP;
    
    	ret = master->ops->send_ccc_cmd(master, cmd);
    	if (ret) {
    		if (cmd->err != I3C_ERROR_UNKNOWN)
    			return cmd->err;
    
    		return ret;
    	}
    
    	return 0;
    }
    
    static struct i2c_dev_desc *
    i3c_master_find_i2c_dev_by_addr(const struct i3c_master_controller *master,
    				u16 addr)
    {
    	struct i2c_dev_desc *dev;
    
    	i3c_bus_for_each_i2cdev(&master->bus, dev) {
    		if (dev->boardinfo->base.addr == addr)
    			return dev;
    	}
    
    	return NULL;
    }
    
    /**
     * i3c_master_get_free_addr() - get a free address on the bus
     * @master: I3C master object
     * @start_addr: where to start searching
     *
     * This function must be called with the bus lock held in write mode.
     *
     * Return: the first free address starting at @start_addr (included) or -ENOMEM
     * if there's no more address available.
     */
    int i3c_master_get_free_addr(struct i3c_master_controller *master,
    			     u8 start_addr)
    {
    	return i3c_bus_get_free_addr(&master->bus, start_addr);
    }
    EXPORT_SYMBOL_GPL(i3c_master_get_free_addr);
    
    static void i3c_device_release(struct device *dev)
    {
    	struct i3c_device *i3cdev = dev_to_i3cdev(dev);
    
    	WARN_ON(i3cdev->desc);
    
    	of_node_put(i3cdev->dev.of_node);
    	kfree(i3cdev);
    }
    
    static void i3c_master_free_i3c_dev(struct i3c_dev_desc *dev)
    {
    	kfree(dev);
    }
    
    static struct i3c_dev_desc *
    i3c_master_alloc_i3c_dev(struct i3c_master_controller *master,
    			 const struct i3c_device_info *info)
    {
    	struct i3c_dev_desc *dev;
    
    	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
    	if (!dev)
    		return ERR_PTR(-ENOMEM);
    
    	dev->common.master = master;
    	dev->info = *info;
    	mutex_init(&dev->ibi_lock);
    
    	return dev;
    }
    
    static int i3c_master_rstdaa_locked(struct i3c_master_controller *master,
    				    u8 addr)
    {
    	enum i3c_addr_slot_status addrstat;
    	struct i3c_ccc_cmd_dest dest;
    	struct i3c_ccc_cmd cmd;
    	int ret;
    
    	if (!master)
    		return -EINVAL;
    
    	addrstat = i3c_bus_get_addr_slot_status(&master->bus, addr);
    	if (addr != I3C_BROADCAST_ADDR && addrstat != I3C_ADDR_SLOT_I3C_DEV)
    		return -EINVAL;
    
    	i3c_ccc_cmd_dest_init(&dest, addr, 0);
    	i3c_ccc_cmd_init(&cmd, false,
    			 I3C_CCC_RSTDAA(addr == I3C_BROADCAST_ADDR),
    			 &dest, 1);
    	ret = i3c_master_send_ccc_cmd_locked(master, &cmd);
    	i3c_ccc_cmd_dest_cleanup(&dest);
    
    	return ret;
    }
    
    /**
     * i3c_master_entdaa_locked() - start a DAA (Dynamic Address Assignment)
     *				procedure
     * @master: master used to send frames on the bus
     *
     * Send a ENTDAA CCC command to start a DAA procedure.
     *
     * Note that this function only sends the ENTDAA CCC command, all the logic
     * behind dynamic address assignment has to be handled in the I3C master
     * driver.
     *
     * This function must be called with the bus lock held in write mode.
     *
     * Return: 0 in case of success, a positive I3C error code if the error is
     * one of the official Mx error codes, and a negative error code otherwise.
     */
    int i3c_master_entdaa_locked(struct i3c_master_controller *master)
    {
    	struct i3c_ccc_cmd_dest dest;
    	struct i3c_ccc_cmd cmd;
    	int ret;
    
    	i3c_ccc_cmd_dest_init(&dest, I3C_BROADCAST_ADDR, 0);
    	i3c_ccc_cmd_init(&cmd, false, I3C_CCC_ENTDAA, &dest, 1);
    	ret = i3c_master_send_ccc_cmd_locked(master, &cmd);
    	i3c_ccc_cmd_dest_cleanup(&dest);
    
    	return ret;
    }
    EXPORT_SYMBOL_GPL(i3c_master_entdaa_locked);
    
    static int i3c_master_enec_disec_locked(struct i3c_master_controller *master,
    					u8 addr, bool enable, u8 evts)
    {
    	struct i3c_ccc_events *events;
    	struct i3c_ccc_cmd_dest dest;
    	struct i3c_ccc_cmd cmd;
    	int ret;
    
    	events = i3c_ccc_cmd_dest_init(&dest, addr, sizeof(*events));
    	if (!events)
    		return -ENOMEM;
    
    	events->events = evts;
    	i3c_ccc_cmd_init(&cmd, false,
    			 enable ?
    			 I3C_CCC_ENEC(addr == I3C_BROADCAST_ADDR) :
    			 I3C_CCC_DISEC(addr == I3C_BROADCAST_ADDR),
    			 &dest, 1);
    	ret = i3c_master_send_ccc_cmd_locked(master, &cmd);
    	i3c_ccc_cmd_dest_cleanup(&dest);
    
    	return ret;
    }
    
    /**
     * i3c_master_disec_locked() - send a DISEC CCC command
     * @master: master used to send frames on the bus
     * @addr: a valid I3C slave address or %I3C_BROADCAST_ADDR
     * @evts: events to disable
     *
     * Send a DISEC CCC command to disable some or all events coming from a
     * specific slave, or all devices if @addr is %I3C_BROADCAST_ADDR.
     *
     * This function must be called with the bus lock held in write mode.
     *
     * Return: 0 in case of success, a positive I3C error code if the error is
     * one of the official Mx error codes, and a negative error code otherwise.
     */
    int i3c_master_disec_locked(struct i3c_master_controller *master, u8 addr,
    			    u8 evts)
    {
    	return i3c_master_enec_disec_locked(master, addr, false, evts);
    }
    EXPORT_SYMBOL_GPL(i3c_master_disec_locked);
    
    /**
     * i3c_master_enec_locked() - send an ENEC CCC command
     * @master: master used to send frames on the bus
     * @addr: a valid I3C slave address or %I3C_BROADCAST_ADDR
     * @evts: events to disable
     *
     * Sends an ENEC CCC command to enable some or all events coming from a
     * specific slave, or all devices if @addr is %I3C_BROADCAST_ADDR.
     *
     * This function must be called with the bus lock held in write mode.
     *
     * Return: 0 in case of success, a positive I3C error code if the error is
     * one of the official Mx error codes, and a negative error code otherwise.
     */
    int i3c_master_enec_locked(struct i3c_master_controller *master, u8 addr,
    			   u8 evts)
    {
    	return i3c_master_enec_disec_locked(master, addr, true, evts);
    }
    EXPORT_SYMBOL_GPL(i3c_master_enec_locked);
    
    /**
     * i3c_master_defslvs_locked() - send a DEFSLVS CCC command
     * @master: master used to send frames on the bus
     *
     * Send a DEFSLVS CCC command containing all the devices known to the @master.
     * This is useful when you have secondary masters on the bus to propagate
     * device information.
     *
     * This should be called after all I3C devices have been discovered (in other
     * words, after the DAA procedure has finished) and instantiated in
     * &i3c_master_controller_ops->bus_init().
     * It should also be called if a master ACKed an Hot-Join request and assigned
     * a dynamic address to the device joining the bus.
     *
     * This function must be called with the bus lock held in write mode.
     *
     * Return: 0 in case of success, a positive I3C error code if the error is
     * one of the official Mx error codes, and a negative error code otherwise.
     */
    int i3c_master_defslvs_locked(struct i3c_master_controller *master)
    {
    	struct i3c_ccc_defslvs *defslvs;
    	struct i3c_ccc_dev_desc *desc;
    	struct i3c_ccc_cmd_dest dest;
    	struct i3c_dev_desc *i3cdev;
    	struct i2c_dev_desc *i2cdev;
    	struct i3c_ccc_cmd cmd;
    	struct i3c_bus *bus;
    	bool send = false;
    	int ndevs = 0, ret;
    
    	if (!master)
    		return -EINVAL;
    
    	bus = i3c_master_get_bus(master);
    	i3c_bus_for_each_i3cdev(bus, i3cdev) {
    		ndevs++;
    
    		if (i3cdev == master->this)
    			continue;
    
    		if (I3C_BCR_DEVICE_ROLE(i3cdev->info.bcr) ==
    		    I3C_BCR_I3C_MASTER)
    			send = true;
    	}
    
    	/* No other master on the bus, skip DEFSLVS. */
    	if (!send)
    		return 0;
    
    	i3c_bus_for_each_i2cdev(bus, i2cdev)
    		ndevs++;
    
    	defslvs = i3c_ccc_cmd_dest_init(&dest, I3C_BROADCAST_ADDR,
    					struct_size(defslvs, slaves,
    						    ndevs - 1));
    	if (!defslvs)
    		return -ENOMEM;
    
    	defslvs->count = ndevs;
    	defslvs->master.bcr = master->this->info.bcr;
    	defslvs->master.dcr = master->this->info.dcr;
    	defslvs->master.dyn_addr = master->this->info.dyn_addr << 1;
    	defslvs->master.static_addr = I3C_BROADCAST_ADDR << 1;
    
    	desc = defslvs->slaves;
    	i3c_bus_for_each_i2cdev(bus, i2cdev) {
    		desc->lvr = i2cdev->lvr;
    		desc->static_addr = i2cdev->addr << 1;
    		desc++;
    	}
    
    	i3c_bus_for_each_i3cdev(bus, i3cdev) {
    		/* Skip the I3C dev representing this master. */
    		if (i3cdev == master->this)
    			continue;
    
    		desc->bcr = i3cdev->info.bcr;
    		desc->dcr = i3cdev->info.dcr;
    		desc->dyn_addr = i3cdev->info.dyn_addr << 1;
    		desc->static_addr = i3cdev->info.static_addr << 1;
    		desc++;
    	}
    
    	i3c_ccc_cmd_init(&cmd, false, I3C_CCC_DEFSLVS, &dest, 1);
    	ret = i3c_master_send_ccc_cmd_locked(master, &cmd);
    	i3c_ccc_cmd_dest_cleanup(&dest);
    
    	return ret;
    }
    EXPORT_SYMBOL_GPL(i3c_master_defslvs_locked);
    
    static int i3c_master_setda_locked(struct i3c_master_controller *master,
    				   u8 oldaddr, u8 newaddr, bool setdasa)
    {
    	struct i3c_ccc_cmd_dest dest;
    	struct i3c_ccc_setda *setda;
    	struct i3c_ccc_cmd cmd;
    	int ret;
    
    	if (!oldaddr || !newaddr)
    		return -EINVAL;
    
    	setda = i3c_ccc_cmd_dest_init(&dest, oldaddr, sizeof(*setda));
    	if (!setda)
    		return -ENOMEM;
    
    	setda->addr = newaddr << 1;
    	i3c_ccc_cmd_init(&cmd, false,
    			 setdasa ? I3C_CCC_SETDASA : I3C_CCC_SETNEWDA,
    			 &dest, 1);
    	ret = i3c_master_send_ccc_cmd_locked(master, &cmd);
    	i3c_ccc_cmd_dest_cleanup(&dest);
    
    	return ret;
    }
    
    static int i3c_master_setdasa_locked(struct i3c_master_controller *master,
    				     u8 static_addr, u8 dyn_addr)
    {
    	return i3c_master_setda_locked(master, static_addr, dyn_addr, true);
    }
    
    static int i3c_master_setnewda_locked(struct i3c_master_controller *master,
    				      u8 oldaddr, u8 newaddr)
    {
    	return i3c_master_setda_locked(master, oldaddr, newaddr, false);
    }
    
    static int i3c_master_getmrl_locked(struct i3c_master_controller *master,
    				    struct i3c_device_info *info)
    {
    	struct i3c_ccc_cmd_dest dest;
    	struct i3c_ccc_mrl *mrl;
    	struct i3c_ccc_cmd cmd;
    	int ret;
    
    	mrl = i3c_ccc_cmd_dest_init(&dest, info->dyn_addr, sizeof(*mrl));
    	if (!mrl)
    		return -ENOMEM;
    
    	/*
    	 * When the device does not have IBI payload GETMRL only returns 2
    	 * bytes of data.
    	 */
    	if (!(info->bcr & I3C_BCR_IBI_PAYLOAD))
    		dest.payload.len -= 1;
    
    	i3c_ccc_cmd_init(&cmd, true, I3C_CCC_GETMRL, &dest, 1);
    	ret = i3c_master_send_ccc_cmd_locked(master, &cmd);
    	if (ret)
    		goto out;
    
    	switch (dest.payload.len) {
    	case 3:
    		info->max_ibi_len = mrl->ibi_len;
    		fallthrough;
    	case 2:
    		info->max_read_len = be16_to_cpu(mrl->read_len);
    		break;
    	default:
    		ret = -EIO;
    		goto out;
    	}
    
    out:
    	i3c_ccc_cmd_dest_cleanup(&dest);
    
    	return ret;
    }
    
    static int i3c_master_getmwl_locked(struct i3c_master_controller *master,
    				    struct i3c_device_info *info)
    {
    	struct i3c_ccc_cmd_dest dest;
    	struct i3c_ccc_mwl *mwl;
    	struct i3c_ccc_cmd cmd;
    	int ret;
    
    	mwl = i3c_ccc_cmd_dest_init(&dest, info->dyn_addr, sizeof(*mwl));
    	if (!mwl)
    		return -ENOMEM;
    
    	i3c_ccc_cmd_init(&cmd, true, I3C_CCC_GETMWL, &dest, 1);
    	ret = i3c_master_send_ccc_cmd_locked(master, &cmd);
    	if (ret)
    		goto out;
    
    	if (dest.payload.len != sizeof(*mwl)) {
    		ret = -EIO;
    		goto out;
    	}
    
    	info->max_write_len = be16_to_cpu(mwl->len);
    
    out:
    	i3c_ccc_cmd_dest_cleanup(&dest);
    
    	return ret;
    }
    
    static int i3c_master_getmxds_locked(struct i3c_master_controller *master,
    				     struct i3c_device_info *info)
    {
    	struct i3c_ccc_getmxds *getmaxds;
    	struct i3c_ccc_cmd_dest dest;
    	struct i3c_ccc_cmd cmd;
    	int ret;
    
    	getmaxds = i3c_ccc_cmd_dest_init(&dest, info->dyn_addr,
    					 sizeof(*getmaxds));
    	if (!getmaxds)
    		return -ENOMEM;
    
    	i3c_ccc_cmd_init(&cmd, true, I3C_CCC_GETMXDS, &dest, 1);
    	ret = i3c_master_send_ccc_cmd_locked(master, &cmd);
    	if (ret)
    		goto out;
    
    	if (dest.payload.len != 2 && dest.payload.len != 5) {
    		ret = -EIO;
    		goto out;
    	}
    
    	info->max_read_ds = getmaxds->maxrd;
    	info->max_write_ds = getmaxds->maxwr;
    	if (dest.payload.len == 5)
    		info->max_read_turnaround = getmaxds->maxrdturn[0] |
    					    ((u32)getmaxds->maxrdturn[1] << 8) |
    					    ((u32)getmaxds->maxrdturn[2] << 16);
    
    out:
    	i3c_ccc_cmd_dest_cleanup(&dest);
    
    	return ret;
    }
    
    static int i3c_master_gethdrcap_locked(struct i3c_master_controller *master,
    				       struct i3c_device_info *info)
    {
    	struct i3c_ccc_gethdrcap *gethdrcap;
    	struct i3c_ccc_cmd_dest dest;
    	struct i3c_ccc_cmd cmd;
    	int ret;
    
    	gethdrcap = i3c_ccc_cmd_dest_init(&dest, info->dyn_addr,
    					  sizeof(*gethdrcap));
    	if (!gethdrcap)
    		return -ENOMEM;
    
    	i3c_ccc_cmd_init(&cmd, true, I3C_CCC_GETHDRCAP, &dest, 1);
    	ret = i3c_master_send_ccc_cmd_locked(master, &cmd);
    	if (ret)
    		goto out;
    
    	if (dest.payload.len != 1) {
    		ret = -EIO;
    		goto out;
    	}
    
    	info->hdr_cap = gethdrcap->modes;
    
    out:
    	i3c_ccc_cmd_dest_cleanup(&dest);
    
    	return ret;
    }
    
    static int i3c_master_getpid_locked(struct i3c_master_controller *master,
    				    struct i3c_device_info *info)
    {
    	struct i3c_ccc_getpid *getpid;
    	struct i3c_ccc_cmd_dest dest;
    	struct i3c_ccc_cmd cmd;
    	int ret, i;
    
    	getpid = i3c_ccc_cmd_dest_init(&dest, info->dyn_addr, sizeof(*getpid));
    	if (!getpid)
    		return -ENOMEM;
    
    	i3c_ccc_cmd_init(&cmd, true, I3C_CCC_GETPID, &dest, 1);
    	ret = i3c_master_send_ccc_cmd_locked(master, &cmd);
    	if (ret)
    		goto out;
    
    	info->pid = 0;
    	for (i = 0; i < sizeof(getpid->pid); i++) {
    		int sft = (sizeof(getpid->pid) - i - 1) * 8;
    
    		info->pid |= (u64)getpid->pid[i] << sft;
    	}
    
    out:
    	i3c_ccc_cmd_dest_cleanup(&dest);
    
    	return ret;
    }
    
    static int i3c_master_getbcr_locked(struct i3c_master_controller *master,
    				    struct i3c_device_info *info)
    {
    	struct i3c_ccc_getbcr *getbcr;
    	struct i3c_ccc_cmd_dest dest;
    	struct i3c_ccc_cmd cmd;
    	int ret;
    
    	getbcr = i3c_ccc_cmd_dest_init(&dest, info->dyn_addr, sizeof(*getbcr));
    	if (!getbcr)
    		return -ENOMEM;
    
    	i3c_ccc_cmd_init(&cmd, true, I3C_CCC_GETBCR, &dest, 1);
    	ret = i3c_master_send_ccc_cmd_locked(master, &cmd);
    	if (ret)
    		goto out;
    
    	info->bcr = getbcr->bcr;
    
    out:
    	i3c_ccc_cmd_dest_cleanup(&dest);
    
    	return ret;
    }
    
    static int i3c_master_getdcr_locked(struct i3c_master_controller *master,
    				    struct i3c_device_info *info)
    {
    	struct i3c_ccc_getdcr *getdcr;
    	struct i3c_ccc_cmd_dest dest;
    	struct i3c_ccc_cmd cmd;
    	int ret;
    
    	getdcr = i3c_ccc_cmd_dest_init(&dest, info->dyn_addr, sizeof(*getdcr));
    	if (!getdcr)
    		return -ENOMEM;
    
    	i3c_ccc_cmd_init(&cmd, true, I3C_CCC_GETDCR, &dest, 1);
    	ret = i3c_master_send_ccc_cmd_locked(master, &cmd);
    	if (ret)
    		goto out;
    
    	info->dcr = getdcr->dcr;
    
    out:
    	i3c_ccc_cmd_dest_cleanup(&dest);
    
    	return ret;
    }
    
    static int i3c_master_retrieve_dev_info(struct i3c_dev_desc *dev)
    {
    	struct i3c_master_controller *master = i3c_dev_get_master(dev);
    	enum i3c_addr_slot_status slot_status;
    	int ret;
    
    	if (!dev->info.dyn_addr)
    		return -EINVAL;
    
    	slot_status = i3c_bus_get_addr_slot_status(&master->bus,
    						   dev->info.dyn_addr);
    	if (slot_status == I3C_ADDR_SLOT_RSVD ||
    	    slot_status == I3C_ADDR_SLOT_I2C_DEV)
    		return -EINVAL;
    
    	ret = i3c_master_getpid_locked(master, &dev->info);
    	if (ret)
    		return ret;
    
    	ret = i3c_master_getbcr_locked(master, &dev->info);
    	if (ret)
    		return ret;
    
    	ret = i3c_master_getdcr_locked(master, &dev->info);
    	if (ret)
    		return ret;
    
    	if (dev->info.bcr & I3C_BCR_MAX_DATA_SPEED_LIM) {
    		ret = i3c_master_getmxds_locked(master, &dev->info);
    		if (ret)
    			return ret;
    	}
    
    	if (dev->info.bcr & I3C_BCR_IBI_PAYLOAD)
    		dev->info.max_ibi_len = 1;
    
    	i3c_master_getmrl_locked(master, &dev->info);
    	i3c_master_getmwl_locked(master, &dev->info);
    
    	if (dev->info.bcr & I3C_BCR_HDR_CAP) {
    		ret = i3c_master_gethdrcap_locked(master, &dev->info);
    		if (ret)
    			return ret;
    	}
    
    	return 0;
    }
    
    static void i3c_master_put_i3c_addrs(struct i3c_dev_desc *dev)
    {
    	struct i3c_master_controller *master = i3c_dev_get_master(dev);
    
    	if (dev->info.static_addr)
    		i3c_bus_set_addr_slot_status(&master->bus,
    					     dev->info.static_addr,
    					     I3C_ADDR_SLOT_FREE);
    
    	if (dev->info.dyn_addr)
    		i3c_bus_set_addr_slot_status(&master->bus, dev->info.dyn_addr,
    					     I3C_ADDR_SLOT_FREE);
    
    	if (dev->boardinfo && dev->boardinfo->init_dyn_addr)
    		i3c_bus_set_addr_slot_status(&master->bus, dev->info.dyn_addr,
    					     I3C_ADDR_SLOT_FREE);
    }
    
    static int i3c_master_get_i3c_addrs(struct i3c_dev_desc *dev)
    {
    	struct i3c_master_controller *master = i3c_dev_get_master(dev);
    	enum i3c_addr_slot_status status;
    
    	if (!dev->info.static_addr && !dev->info.dyn_addr)
    		return 0;
    
    	if (dev->info.static_addr) {
    		status = i3c_bus_get_addr_slot_status(&master->bus,
    						      dev->info.static_addr);
    		if (status != I3C_ADDR_SLOT_FREE)
    			return -EBUSY;
    
    		i3c_bus_set_addr_slot_status(&master->bus,
    					     dev->info.static_addr,
    					     I3C_ADDR_SLOT_I3C_DEV);
    	}
    
    	/*
    	 * ->init_dyn_addr should have been reserved before that, so, if we're
    	 * trying to apply a pre-reserved dynamic address, we should not try
    	 * to reserve the address slot a second time.
    	 */
    	if (dev->info.dyn_addr &&
    	    (!dev->boardinfo ||
    	     dev->boardinfo->init_dyn_addr != dev->info.dyn_addr)) {
    		status = i3c_bus_get_addr_slot_status(&master->bus,
    						      dev->info.dyn_addr);
    		if (status != I3C_ADDR_SLOT_FREE)
    			goto err_release_static_addr;
    
    		i3c_bus_set_addr_slot_status(&master->bus, dev->info.dyn_addr,
    					     I3C_ADDR_SLOT_I3C_DEV);
    	}
    
    	return 0;
    
    err_release_static_addr:
    	if (dev->info.static_addr)
    		i3c_bus_set_addr_slot_status(&master->bus,
    					     dev->info.static_addr,
    					     I3C_ADDR_SLOT_FREE);
    
    	return -EBUSY;
    }
    
    static int i3c_master_attach_i3c_dev(struct i3c_master_controller *master,
    				     struct i3c_dev_desc *dev)
    {
    	int ret;
    
    	/*
    	 * We don't attach devices to the controller until they are
    	 * addressable on the bus.
    	 */
    	if (!dev->info.static_addr && !dev->info.dyn_addr)
    		return 0;
    
    	ret = i3c_master_get_i3c_addrs(dev);
    	if (ret)
    		return ret;
    
    	/* Do not attach the master device itself. */
    	if (master->this != dev && master->ops->attach_i3c_dev) {
    		ret = master->ops->attach_i3c_dev(dev);
    		if (ret) {
    			i3c_master_put_i3c_addrs(dev);
    			return ret;
    		}
    	}
    
    	list_add_tail(&dev->common.node, &master->bus.devs.i3c);
    
    	return 0;
    }
    
    static int i3c_master_reattach_i3c_dev(struct i3c_dev_desc *dev,
    				       u8 old_dyn_addr)
    {
    	struct i3c_master_controller *master = i3c_dev_get_master(dev);
    	enum i3c_addr_slot_status status;
    	int ret;
    
    	if (dev->info.dyn_addr != old_dyn_addr &&
    	    (!dev->boardinfo ||
    	     dev->info.dyn_addr != dev->boardinfo->init_dyn_addr)) {
    		status = i3c_bus_get_addr_slot_status(&master->bus,
    						      dev->info.dyn_addr);
    		if (status != I3C_ADDR_SLOT_FREE)
    			return -EBUSY;
    		i3c_bus_set_addr_slot_status(&master->bus,
    					     dev->info.dyn_addr,
    					     I3C_ADDR_SLOT_I3C_DEV);
    	}
    
    	if (master->ops->reattach_i3c_dev) {
    		ret = master->ops->reattach_i3c_dev(dev, old_dyn_addr);
    		if (ret) {
    			i3c_master_put_i3c_addrs(dev);
    			return ret;
    		}
    	}
    
    	return 0;
    }
    
    static void i3c_master_detach_i3c_dev(struct i3c_dev_desc *dev)
    {
    	struct i3c_master_controller *master = i3c_dev_get_master(dev);
    
    	/* Do not detach the master device itself. */
    	if (master->this != dev && master->ops->detach_i3c_dev)
    		master->ops->detach_i3c_dev(dev);
    
    	i3c_master_put_i3c_addrs(dev);
    	list_del(&dev->common.node);
    }
    
    static int i3c_master_attach_i2c_dev(struct i3c_master_controller *master,
    				     struct i2c_dev_desc *dev)
    {
    	int ret;
    
    	if (master->ops->attach_i2c_dev) {
    		ret = master->ops->attach_i2c_dev(dev);
    		if (ret)
    			return ret;
    	}
    
    	list_add_tail(&dev->common.node, &master->bus.devs.i2c);
    
    	return 0;
    }
    
    static void i3c_master_detach_i2c_dev(struct i2c_dev_desc *dev)
    {
    	struct i3c_master_controller *master = i2c_dev_get_master(dev);
    
    	list_del(&dev->common.node);
    
    	if (master->ops->detach_i2c_dev)
    		master->ops->detach_i2c_dev(dev);
    }
    
    static int i3c_master_early_i3c_dev_add(struct i3c_master_controller *master,
    					  struct i3c_dev_boardinfo *boardinfo)
    {
    	struct i3c_device_info info = {
    		.static_addr = boardinfo->static_addr,
    	};
    	struct i3c_dev_desc *i3cdev;
    	int ret;
    
    	i3cdev = i3c_master_alloc_i3c_dev(master, &info);
    	if (IS_ERR(i3cdev))
    		return -ENOMEM;
    
    	i3cdev->boardinfo = boardinfo;
    
    	ret = i3c_master_attach_i3c_dev(master, i3cdev);
    	if (ret)
    		goto err_free_dev;
    
    	ret = i3c_master_setdasa_locked(master, i3cdev->info.static_addr,
    					i3cdev->boardinfo->init_dyn_addr);
    	if (ret)
    		goto err_detach_dev;
    
    	i3cdev->info.dyn_addr = i3cdev->boardinfo->init_dyn_addr;
    	ret = i3c_master_reattach_i3c_dev(i3cdev, 0);
    	if (ret)
    		goto err_rstdaa;
    
    	ret = i3c_master_retrieve_dev_info(i3cdev);
    	if (ret)
    		goto err_rstdaa;
    
    	return 0;
    
    err_rstdaa:
    	i3c_master_rstdaa_locked(master, i3cdev->boardinfo->init_dyn_addr);
    err_detach_dev:
    	i3c_master_detach_i3c_dev(i3cdev);
    err_free_dev:
    	i3c_master_free_i3c_dev(i3cdev);
    
    	return ret;
    }
    
    static void
    i3c_master_register_new_i3c_devs(struct i3c_master_controller *master)
    {
    	struct i3c_dev_desc *desc;
    	int ret;
    
    	if (!master->init_done)
    		return;
    
    	i3c_bus_for_each_i3cdev(&master->bus, desc) {
    		if (desc->dev || !desc->info.dyn_addr || desc == master->this)
    			continue;
    
    		desc->dev = kzalloc(sizeof(*desc->dev), GFP_KERNEL);
    		if (!desc->dev)
    			continue;
    
    		desc->dev->bus = &master->bus;
    		desc->dev->desc = desc;
    		desc->dev->dev.parent = &master->dev;
    		desc->dev->dev.type = &i3c_device_type;
    		desc->dev->dev.bus = &i3c_bus_type;
    		desc->dev->dev.release = i3c_device_release;
    		dev_set_name(&desc->dev->dev, "%d-%llx", master->bus.id,
    			     desc->info.pid);
    
    		if (desc->boardinfo)
    			desc->dev->dev.of_node = desc->boardinfo->of_node;
    
    		ret = device_register(&desc->dev->dev);
    		if (ret)
    			dev_err(&master->dev,
    				"Failed to add I3C device (err = %d)\n", ret);
    	}
    }
    
    /**
     * i3c_master_do_daa() - do a DAA (Dynamic Address Assignment)
     * @master: master doing the DAA
     *
     * This function is instantiating an I3C device object and adding it to the
     * I3C device list. All device information are automatically retrieved using
     * standard CCC commands.
     *
     * The I3C device object is returned in case the master wants to attach
     * private data to it using i3c_dev_set_master_data().
     *
     * This function must be called with the bus lock held in write mode.
     *
     * Return: a 0 in case of success, an negative error code otherwise.
     */
    int i3c_master_do_daa(struct i3c_master_controller *master)
    {
    	int ret;
    
    	i3c_bus_maintenance_lock(&master->bus);
    	ret = master->ops->do_daa(master);
    	i3c_bus_maintenance_unlock(&master->bus);
    
    	if (ret)
    		return ret;
    
    	i3c_bus_normaluse_lock(&master->bus);
    	i3c_master_register_new_i3c_devs(master);
    	i3c_bus_normaluse_unlock(&master->bus);
    
    	return 0;
    }
    EXPORT_SYMBOL_GPL(i3c_master_do_daa);
    
    /**
     * i3c_master_set_info() - set master device information
     * @master: master used to send frames on the bus
     * @info: I3C device information
     *
     * Set master device info. This should be called from
     * &i3c_master_controller_ops->bus_init().
     *
     * Not all &i3c_device_info fields are meaningful for a master device.
     * Here is a list of fields that should be properly filled:
     *
     * - &i3c_device_info->dyn_addr
     * - &i3c_device_info->bcr
     * - &i3c_device_info->dcr
     * - &i3c_device_info->pid
     * - &i3c_device_info->hdr_cap if %I3C_BCR_HDR_CAP bit is set in
     *   &i3c_device_info->bcr
     *
     * This function must be called with the bus lock held in maintenance mode.
     *
     * Return: 0 if @info contains valid information (not every piece of
     * information can be checked, but we can at least make sure @info->dyn_addr
     * and @info->bcr are correct), -EINVAL otherwise.
     */
    int i3c_master_set_info(struct i3c_master_controller *master,
    			const struct i3c_device_info *info)
    {
    	struct i3c_dev_desc *i3cdev;
    	int ret;
    
    	if (!i3c_bus_dev_addr_is_avail(&master->bus, info->dyn_addr))
    		return -EINVAL;
    
    	if (I3C_BCR_DEVICE_ROLE(info->bcr) == I3C_BCR_I3C_MASTER &&
    	    master->secondary)
    		return -EINVAL;
    
    	if (master->this)
    		return -EINVAL;
    
    	i3cdev = i3c_master_alloc_i3c_dev(master, info);
    	if (IS_ERR(i3cdev))
    		return PTR_ERR(i3cdev);
    
    	master->this = i3cdev;
    	master->bus.cur_master = master->this;
    
    	ret = i3c_master_attach_i3c_dev(master, i3cdev);
    	if (ret)
    		goto err_free_dev;
    
    	return 0;
    
    err_free_dev:
    	i3c_master_free_i3c_dev(i3cdev);
    
    	return ret;
    }
    EXPORT_SYMBOL_GPL(i3c_master_set_info);
    
    static void i3c_master_detach_free_devs(struct i3c_master_controller *master)
    {
    	struct i3c_dev_desc *i3cdev, *i3ctmp;
    	struct i2c_dev_desc *i2cdev, *i2ctmp;
    
    	list_for_each_entry_safe(i3cdev, i3ctmp, &master->bus.devs.i3c,
    				 common.node) {
    		i3c_master_detach_i3c_dev(i3cdev);
    
    		if (i3cdev->boardinfo && i3cdev->boardinfo->init_dyn_addr)
    			i3c_bus_set_addr_slot_status(&master->bus,
    					i3cdev->boardinfo->init_dyn_addr,
    					I3C_ADDR_SLOT_FREE);
    
    		i3c_master_free_i3c_dev(i3cdev);
    	}
    
    	list_for_each_entry_safe(i2cdev, i2ctmp, &master->bus.devs.i2c,
    				 common.node) {
    		i3c_master_detach_i2c_dev(i2cdev);
    		i3c_bus_set_addr_slot_status(&master->bus,
    					     i2cdev->addr,
    					     I3C_ADDR_SLOT_FREE);
    		i3c_master_free_i2c_dev(i2cdev);
    	}
    }
    
    /**
     * i3c_master_bus_init() - initialize an I3C bus
     * @master: main master initializing the bus
     *
     * This function is following all initialisation steps described in the I3C
     * specification:
     *
     * 1. Attach I2C devs to the master so that the master can fill its internal
     *    device table appropriately
     *
     * 2. Call &i3c_master_controller_ops->bus_init() method to initialize
     *    the master controller. That's usually where the bus mode is selected
     *    (pure bus or mixed fast/slow bus)
     *
     * 3. Instruct all devices on the bus to drop their dynamic address. This is
     *    particularly important when the bus was previously configured by someone
     *    else (for example the bootloader)
     *
     * 4. Disable all slave events.
     *
     * 5. Reserve address slots for I3C devices with init_dyn_addr. And if devices
     *    also have static_addr, try to pre-assign dynamic addresses requested by
     *    the FW with SETDASA and attach corresponding statically defined I3C
     *    devices to the master.
     *
     * 6. Do a DAA (Dynamic Address Assignment) to assign dynamic addresses to all
     *    remaining I3C devices
     *
     * Once this is done, all I3C and I2C devices should be usable.
     *
     * Return: a 0 in case of success, an negative error code otherwise.
     */
    static int i3c_master_bus_init(struct i3c_master_controller *master)
    {
    	enum i3c_addr_slot_status status;
    	struct i2c_dev_boardinfo *i2cboardinfo;
    	struct i3c_dev_boardinfo *i3cboardinfo;
    	struct i2c_dev_desc *i2cdev;
    	int ret;
    
    	/*
    	 * First attach all devices with static definitions provided by the
    	 * FW.
    	 */
    	list_for_each_entry(i2cboardinfo, &master->boardinfo.i2c, node) {
    		status = i3c_bus_get_addr_slot_status(&master->bus,
    						      i2cboardinfo->base.addr);
    		if (status != I3C_ADDR_SLOT_FREE) {
    			ret = -EBUSY;
    			goto err_detach_devs;
    		}
    
    		i3c_bus_set_addr_slot_status(&master->bus,
    					     i2cboardinfo->base.addr,
    					     I3C_ADDR_SLOT_I2C_DEV);
    
    		i2cdev = i3c_master_alloc_i2c_dev(master, i2cboardinfo);
    		if (IS_ERR(i2cdev)) {
    			ret = PTR_ERR(i2cdev);
    			goto err_detach_devs;
    		}
    
    		ret = i3c_master_attach_i2c_dev(master, i2cdev);
    		if (ret) {
    			i3c_master_free_i2c_dev(i2cdev);
    			goto err_detach_devs;
    		}
    	}
    
    	/*
    	 * Now execute the controller specific ->bus_init() routine, which
    	 * might configure its internal logic to match the bus limitations.
    	 */
    	ret = master->ops->bus_init(master);
    	if (ret)
    		goto err_detach_devs;
    
    	/*
    	 * The master device should have been instantiated in ->bus_init(),
    	 * complain if this was not the case.
    	 */
    	if (!master->this) {
    		dev_err(&master->dev,
    			"master_set_info() was not called in ->bus_init()\n");
    		ret = -EINVAL;
    		goto err_bus_cleanup;
    	}
    
    	/*
    	 * Reset all dynamic address that may have been assigned before
    	 * (assigned by the bootloader for example).
    	 */
    	ret = i3c_master_rstdaa_locked(master, I3C_BROADCAST_ADDR);
    	if (ret && ret != I3C_ERROR_M2)
    		goto err_bus_cleanup;
    
    	/* Disable all slave events before starting DAA. */
    	ret = i3c_master_disec_locked(master, I3C_BROADCAST_ADDR,
    				      I3C_CCC_EVENT_SIR | I3C_CCC_EVENT_MR |
    				      I3C_CCC_EVENT_HJ);
    	if (ret && ret != I3C_ERROR_M2)
    		goto err_bus_cleanup;
    
    	/*
    	 * Reserve init_dyn_addr first, and then try to pre-assign dynamic
    	 * address and retrieve device information if needed.
    	 * In case pre-assign dynamic address fails, setting dynamic address to
    	 * the requested init_dyn_addr is retried after DAA is done in
    	 * i3c_master_add_i3c_dev_locked().
    	 */
    	list_for_each_entry(i3cboardinfo, &master->boardinfo.i3c, node) {
    
    		/*
    		 * We don't reserve a dynamic address for devices that
    		 * don't explicitly request one.
    		 */
    		if (!i3cboardinfo->init_dyn_addr)
    			continue;
    
    		ret = i3c_bus_get_addr_slot_status(&master->bus,
    						   i3cboardinfo->init_dyn_addr);
    		if (ret != I3C_ADDR_SLOT_FREE) {
    			ret = -EBUSY;
    			goto err_rstdaa;
    		}
    
    		i3c_bus_set_addr_slot_status(&master->bus,
    					     i3cboardinfo->init_dyn_addr,
    					     I3C_ADDR_SLOT_I3C_DEV);
    
    		/*
    		 * Only try to create/attach devices that have a static
    		 * address. Other devices will be created/attached when
    		 * DAA happens, and the requested dynamic address will
    		 * be set using SETNEWDA once those devices become
    		 * addressable.
    		 */
    
    		if (i3cboardinfo->static_addr)
    			i3c_master_early_i3c_dev_add(master, i3cboardinfo);
    	}
    
    	ret = i3c_master_do_daa(master);
    	if (ret)
    		goto err_rstdaa;
    
    	return 0;
    
    err_rstdaa:
    	i3c_master_rstdaa_locked(master, I3C_BROADCAST_ADDR);
    
    err_bus_cleanup:
    	if (master->ops->bus_cleanup)
    		master->ops->bus_cleanup(master);
    
    err_detach_devs:
    	i3c_master_detach_free_devs(master);
    
    	return ret;
    }
    
    static void i3c_master_bus_cleanup(struct i3c_master_controller *master)
    {
    	if (master->ops->bus_cleanup)
    		master->ops->bus_cleanup(master);
    
    	i3c_master_detach_free_devs(master);
    }
    
    static void i3c_master_attach_boardinfo(struct i3c_dev_desc *i3cdev)
    {
    	struct i3c_master_controller *master = i3cdev->common.master;
    	struct i3c_dev_boardinfo *i3cboardinfo;
    
    	list_for_each_entry(i3cboardinfo, &master->boardinfo.i3c, node) {
    		if (i3cdev->info.pid != i3cboardinfo->pid)
    			continue;
    
    		i3cdev->boardinfo = i3cboardinfo;
    		i3cdev->info.static_addr = i3cboardinfo->static_addr;
    		return;
    	}
    }
    
    static struct i3c_dev_desc *
    i3c_master_search_i3c_dev_duplicate(struct i3c_dev_desc *refdev)
    {
    	struct i3c_master_controller *master = i3c_dev_get_master(refdev);
    	struct i3c_dev_desc *i3cdev;
    
    	i3c_bus_for_each_i3cdev(&master->bus, i3cdev) {
    		if (i3cdev != refdev && i3cdev->info.pid == refdev->info.pid)
    			return i3cdev;
    	}
    
    	return NULL;
    }
    
    /**
     * i3c_master_add_i3c_dev_locked() - add an I3C slave to the bus
     * @master: master used to send frames on the bus
     * @addr: I3C slave dynamic address assigned to the device
     *
     * This function is instantiating an I3C device object and adding it to the
     * I3C device list. All device information are automatically retrieved using
     * standard CCC commands.
     *
     * The I3C device object is returned in case the master wants to attach
     * private data to it using i3c_dev_set_master_data().
     *
     * This function must be called with the bus lock held in write mode.
     *
     * Return: a 0 in case of success, an negative error code otherwise.
     */
    int i3c_master_add_i3c_dev_locked(struct i3c_master_controller *master,
    				  u8 addr)
    {
    	struct i3c_device_info info = { .dyn_addr = addr };
    	struct i3c_dev_desc *newdev, *olddev;
    	u8 old_dyn_addr = addr, expected_dyn_addr;
    	struct i3c_ibi_setup ibireq = { };
    	bool enable_ibi = false;
    	int ret;
    
    	if (!master)
    		return -EINVAL;
    
    	newdev = i3c_master_alloc_i3c_dev(master, &info);
    	if (IS_ERR(newdev))
    		return PTR_ERR(newdev);
    
    	ret = i3c_master_attach_i3c_dev(master, newdev);
    	if (ret)
    		goto err_free_dev;
    
    	ret = i3c_master_retrieve_dev_info(newdev);
    	if (ret)
    		goto err_detach_dev;
    
    	i3c_master_attach_boardinfo(newdev);
    
    	olddev = i3c_master_search_i3c_dev_duplicate(newdev);
    	if (olddev) {
    		newdev->dev = olddev->dev;
    		if (newdev->dev)
    			newdev->dev->desc = newdev;
    
    		/*
    		 * We need to restore the IBI state too, so let's save the
    		 * IBI information and try to restore them after olddev has
    		 * been detached+released and its IBI has been stopped and
    		 * the associated resources have been freed.
    		 */
    		mutex_lock(&olddev->ibi_lock);
    		if (olddev->ibi) {
    			ibireq.handler = olddev->ibi->handler;
    			ibireq.max_payload_len = olddev->ibi->max_payload_len;
    			ibireq.num_slots = olddev->ibi->num_slots;
    
    			if (olddev->ibi->enabled) {
    				enable_ibi = true;
    				i3c_dev_disable_ibi_locked(olddev);
    			}
    
    			i3c_dev_free_ibi_locked(olddev);
    		}
    		mutex_unlock(&olddev->ibi_lock);
    
    		old_dyn_addr = olddev->info.dyn_addr;
    
    		i3c_master_detach_i3c_dev(olddev);
    		i3c_master_free_i3c_dev(olddev);
    	}
    
    	ret = i3c_master_reattach_i3c_dev(newdev, old_dyn_addr);
    	if (ret)
    		goto err_detach_dev;
    
    	/*
    	 * Depending on our previous state, the expected dynamic address might
    	 * differ:
    	 * - if the device already had a dynamic address assigned, let's try to
    	 *   re-apply this one
    	 * - if the device did not have a dynamic address and the firmware
    	 *   requested a specific address, pick this one
    	 * - in any other case, keep the address automatically assigned by the
    	 *   master
    	 */
    	if (old_dyn_addr && old_dyn_addr != newdev->info.dyn_addr)
    		expected_dyn_addr = old_dyn_addr;
    	else if (newdev->boardinfo && newdev->boardinfo->init_dyn_addr)
    		expected_dyn_addr = newdev->boardinfo->init_dyn_addr;
    	else
    		expected_dyn_addr = newdev->info.dyn_addr;
    
    	if (newdev->info.dyn_addr != expected_dyn_addr) {
    		/*
    		 * Try to apply the expected dynamic address. If it fails, keep
    		 * the address assigned by the master.
    		 */
    		ret = i3c_master_setnewda_locked(master,
    						 newdev->info.dyn_addr,
    						 expected_dyn_addr);
    		if (!ret) {
    			old_dyn_addr = newdev->info.dyn_addr;
    			newdev->info.dyn_addr = expected_dyn_addr;
    			i3c_master_reattach_i3c_dev(newdev, old_dyn_addr);
    		} else {
    			dev_err(&master->dev,
    				"Failed to assign reserved/old address to device %d%llx",
    				master->bus.id, newdev->info.pid);
    		}
    	}
    
    	/*
    	 * Now is time to try to restore the IBI setup. If we're lucky,
    	 * everything works as before, otherwise, all we can do is complain.
    	 * FIXME: maybe we should add callback to inform the driver that it
    	 * should request the IBI again instead of trying to hide that from
    	 * him.
    	 */
    	if (ibireq.handler) {
    		mutex_lock(&newdev->ibi_lock);
    		ret = i3c_dev_request_ibi_locked(newdev, &ibireq);
    		if (ret) {
    			dev_err(&master->dev,
    				"Failed to request IBI on device %d-%llx",
    				master->bus.id, newdev->info.pid);
    		} else if (enable_ibi) {
    			ret = i3c_dev_enable_ibi_locked(newdev);
    			if (ret)
    				dev_err(&master->dev,
    					"Failed to re-enable IBI on device %d-%llx",
    					master->bus.id, newdev->info.pid);
    		}
    		mutex_unlock(&newdev->ibi_lock);
    	}
    
    	return 0;
    
    err_detach_dev:
    	if (newdev->dev && newdev->dev->desc)
    		newdev->dev->desc = NULL;
    
    	i3c_master_detach_i3c_dev(newdev);
    
    err_free_dev:
    	i3c_master_free_i3c_dev(newdev);
    
    	return ret;
    }
    EXPORT_SYMBOL_GPL(i3c_master_add_i3c_dev_locked);
    
    #define OF_I3C_REG1_IS_I2C_DEV			BIT(31)
    
    static int
    of_i3c_master_add_i2c_boardinfo(struct i3c_master_controller *master,
    				struct device_node *node, u32 *reg)
    {
    	struct i2c_dev_boardinfo *boardinfo;
    	struct device *dev = &master->dev;
    	int ret;
    
    	boardinfo = devm_kzalloc(dev, sizeof(*boardinfo), GFP_KERNEL);
    	if (!boardinfo)
    		return -ENOMEM;
    
    	ret = of_i2c_get_board_info(dev, node, &boardinfo->base);
    	if (ret)
    		return ret;
    
    	/*
    	 * The I3C Specification does not clearly say I2C devices with 10-bit
    	 * address are supported. These devices can't be passed properly through
    	 * DEFSLVS command.
    	 */
    	if (boardinfo->base.flags & I2C_CLIENT_TEN) {
    		dev_err(dev, "I2C device with 10 bit address not supported.");
    		return -ENOTSUPP;
    	}
    
    	/* LVR is encoded in reg[2]. */
    	boardinfo->lvr = reg[2];
    
    	list_add_tail(&boardinfo->node, &master->boardinfo.i2c);
    	of_node_get(node);
    
    	return 0;
    }
    
    static int
    of_i3c_master_add_i3c_boardinfo(struct i3c_master_controller *master,
    				struct device_node *node, u32 *reg)
    {
    	struct i3c_dev_boardinfo *boardinfo;
    	struct device *dev = &master->dev;
    	enum i3c_addr_slot_status addrstatus;
    	u32 init_dyn_addr = 0;
    
    	boardinfo = devm_kzalloc(dev, sizeof(*boardinfo), GFP_KERNEL);
    	if (!boardinfo)
    		return -ENOMEM;
    
    	if (reg[0]) {
    		if (reg[0] > I3C_MAX_ADDR)
    			return -EINVAL;
    
    		addrstatus = i3c_bus_get_addr_slot_status(&master->bus,
    							  reg[0]);
    		if (addrstatus != I3C_ADDR_SLOT_FREE)
    			return -EINVAL;
    	}
    
    	boardinfo->static_addr = reg[0];
    
    	if (!of_property_read_u32(node, "assigned-address", &init_dyn_addr)) {
    		if (init_dyn_addr > I3C_MAX_ADDR)
    			return -EINVAL;
    
    		addrstatus = i3c_bus_get_addr_slot_status(&master->bus,
    							  init_dyn_addr);
    		if (addrstatus != I3C_ADDR_SLOT_FREE)
    			return -EINVAL;
    	}
    
    	boardinfo->pid = ((u64)reg[1] << 32) | reg[2];
    
    	if ((boardinfo->pid & GENMASK_ULL(63, 48)) ||
    	    I3C_PID_RND_LOWER_32BITS(boardinfo->pid))
    		return -EINVAL;
    
    	boardinfo->init_dyn_addr = init_dyn_addr;
    	boardinfo->of_node = of_node_get(node);
    	list_add_tail(&boardinfo->node, &master->boardinfo.i3c);
    
    	return 0;
    }
    
    static int of_i3c_master_add_dev(struct i3c_master_controller *master,
    				 struct device_node *node)
    {
    	u32 reg[3];
    	int ret;
    
    	if (!master || !node)
    		return -EINVAL;
    
    	ret = of_property_read_u32_array(node, "reg", reg, ARRAY_SIZE(reg));
    	if (ret)
    		return ret;
    
    	/*
    	 * The manufacturer ID can't be 0. If reg[1] == 0 that means we're
    	 * dealing with an I2C device.
    	 */
    	if (!reg[1])
    		ret = of_i3c_master_add_i2c_boardinfo(master, node, reg);
    	else
    		ret = of_i3c_master_add_i3c_boardinfo(master, node, reg);
    
    	return ret;
    }
    
    static int of_populate_i3c_bus(struct i3c_master_controller *master)
    {
    	struct device *dev = &master->dev;
    	struct device_node *i3cbus_np = dev->of_node;
    	struct device_node *node;
    	int ret;
    	u32 val;
    
    	if (!i3cbus_np)
    		return 0;
    
    	for_each_available_child_of_node(i3cbus_np, node) {
    		ret = of_i3c_master_add_dev(master, node);
    		if (ret) {
    			of_node_put(node);
    			return ret;
    		}
    	}
    
    	/*
    	 * The user might want to limit I2C and I3C speed in case some devices
    	 * on the bus are not supporting typical rates, or if the bus topology
    	 * prevents it from using max possible rate.
    	 */
    	if (!of_property_read_u32(i3cbus_np, "i2c-scl-hz", &val))
    		master->bus.scl_rate.i2c = val;
    
    	if (!of_property_read_u32(i3cbus_np, "i3c-scl-hz", &val))
    		master->bus.scl_rate.i3c = val;
    
    	return 0;
    }
    
    static int i3c_master_i2c_adapter_xfer(struct i2c_adapter *adap,
    				       struct i2c_msg *xfers, int nxfers)
    {
    	struct i3c_master_controller *master = i2c_adapter_to_i3c_master(adap);
    	struct i2c_dev_desc *dev;
    	int i, ret;
    	u16 addr;
    
    	if (!xfers || !master || nxfers <= 0)
    		return -EINVAL;
    
    	if (!master->ops->i2c_xfers)
    		return -ENOTSUPP;
    
    	/* Doing transfers to different devices is not supported. */
    	addr = xfers[0].addr;
    	for (i = 1; i < nxfers; i++) {
    		if (addr != xfers[i].addr)
    			return -ENOTSUPP;
    	}
    
    	i3c_bus_normaluse_lock(&master->bus);
    	dev = i3c_master_find_i2c_dev_by_addr(master, addr);
    	if (!dev)
    		ret = -ENOENT;
    	else
    		ret = master->ops->i2c_xfers(dev, xfers, nxfers);
    	i3c_bus_normaluse_unlock(&master->bus);
    
    	return ret ? ret : nxfers;
    }
    
    static u32 i3c_master_i2c_funcs(struct i2c_adapter *adapter)
    {
    	return I2C_FUNC_SMBUS_EMUL | I2C_FUNC_I2C;
    }
    
    static const struct i2c_algorithm i3c_master_i2c_algo = {
    	.master_xfer = i3c_master_i2c_adapter_xfer,
    	.functionality = i3c_master_i2c_funcs,
    };
    
    static int i3c_master_i2c_adapter_init(struct i3c_master_controller *master)
    {
    	struct i2c_adapter *adap = i3c_master_to_i2c_adapter(master);
    	struct i2c_dev_desc *i2cdev;
    	int ret;
    
    	adap->dev.parent = master->dev.parent;
    	adap->owner = master->dev.parent->driver->owner;
    	adap->algo = &i3c_master_i2c_algo;
    	strncpy(adap->name, dev_name(master->dev.parent), sizeof(adap->name));
    
    	/* FIXME: Should we allow i3c masters to override these values? */
    	adap->timeout = 1000;
    	adap->retries = 3;
    
    	ret = i2c_add_adapter(adap);
    	if (ret)
    		return ret;
    
    	/*
    	 * We silently ignore failures here. The bus should keep working
    	 * correctly even if one or more i2c devices are not registered.
    	 */
    	i3c_bus_for_each_i2cdev(&master->bus, i2cdev)
    		i2cdev->dev = i2c_new_client_device(adap, &i2cdev->boardinfo->base);
    
    	return 0;
    }
    
    static void i3c_master_i2c_adapter_cleanup(struct i3c_master_controller *master)
    {
    	struct i2c_dev_desc *i2cdev;
    
    	i2c_del_adapter(&master->i2c);
    
    	i3c_bus_for_each_i2cdev(&master->bus, i2cdev)
    		i2cdev->dev = NULL;
    }
    
    static void i3c_master_unregister_i3c_devs(struct i3c_master_controller *master)
    {
    	struct i3c_dev_desc *i3cdev;
    
    	i3c_bus_for_each_i3cdev(&master->bus, i3cdev) {
    		if (!i3cdev->dev)
    			continue;
    
    		i3cdev->dev->desc = NULL;
    		if (device_is_registered(&i3cdev->dev->dev))
    			device_unregister(&i3cdev->dev->dev);
    		else
    			put_device(&i3cdev->dev->dev);
    		i3cdev->dev = NULL;
    	}
    }
    
    /**
     * i3c_master_queue_ibi() - Queue an IBI
     * @dev: the device this IBI is coming from
     * @slot: the IBI slot used to store the payload
     *
     * Queue an IBI to the controller workqueue. The IBI handler attached to
     * the dev will be called from a workqueue context.
     */
    void i3c_master_queue_ibi(struct i3c_dev_desc *dev, struct i3c_ibi_slot *slot)
    {
    	atomic_inc(&dev->ibi->pending_ibis);
    	queue_work(dev->common.master->wq, &slot->work);
    }
    EXPORT_SYMBOL_GPL(i3c_master_queue_ibi);
    
    static void i3c_master_handle_ibi(struct work_struct *work)
    {
    	struct i3c_ibi_slot *slot = container_of(work, struct i3c_ibi_slot,
    						 work);
    	struct i3c_dev_desc *dev = slot->dev;
    	struct i3c_master_controller *master = i3c_dev_get_master(dev);
    	struct i3c_ibi_payload payload;
    
    	payload.data = slot->data;
    	payload.len = slot->len;
    
    	if (dev->dev)
    		dev->ibi->handler(dev->dev, &payload);
    
    	master->ops->recycle_ibi_slot(dev, slot);
    	if (atomic_dec_and_test(&dev->ibi->pending_ibis))
    		complete(&dev->ibi->all_ibis_handled);
    }
    
    static void i3c_master_init_ibi_slot(struct i3c_dev_desc *dev,
    				     struct i3c_ibi_slot *slot)
    {
    	slot->dev = dev;
    	INIT_WORK(&slot->work, i3c_master_handle_ibi);
    }
    
    struct i3c_generic_ibi_slot {
    	struct list_head node;
    	struct i3c_ibi_slot base;
    };
    
    struct i3c_generic_ibi_pool {
    	spinlock_t lock;
    	unsigned int num_slots;
    	struct i3c_generic_ibi_slot *slots;
    	void *payload_buf;
    	struct list_head free_slots;
    	struct list_head pending;
    };
    
    /**
     * i3c_generic_ibi_free_pool() - Free a generic IBI pool
     * @pool: the IBI pool to free
     *
     * Free all IBI slots allated by a generic IBI pool.
     */
    void i3c_generic_ibi_free_pool(struct i3c_generic_ibi_pool *pool)
    {
    	struct i3c_generic_ibi_slot *slot;
    	unsigned int nslots = 0;
    
    	while (!list_empty(&pool->free_slots)) {
    		slot = list_first_entry(&pool->free_slots,
    					struct i3c_generic_ibi_slot, node);
    		list_del(&slot->node);
    		nslots++;
    	}
    
    	/*
    	 * If the number of freed slots is not equal to the number of allocated
    	 * slots we have a leak somewhere.
    	 */
    	WARN_ON(nslots != pool->num_slots);
    
    	kfree(pool->payload_buf);
    	kfree(pool->slots);
    	kfree(pool);
    }
    EXPORT_SYMBOL_GPL(i3c_generic_ibi_free_pool);
    
    /**
     * i3c_generic_ibi_alloc_pool() - Create a generic IBI pool
     * @dev: the device this pool will be used for
     * @req: IBI setup request describing what the device driver expects
     *
     * Create a generic IBI pool based on the information provided in @req.
     *
     * Return: a valid IBI pool in case of success, an ERR_PTR() otherwise.
     */
    struct i3c_generic_ibi_pool *
    i3c_generic_ibi_alloc_pool(struct i3c_dev_desc *dev,
    			   const struct i3c_ibi_setup *req)
    {
    	struct i3c_generic_ibi_pool *pool;
    	struct i3c_generic_ibi_slot *slot;
    	unsigned int i;
    	int ret;
    
    	pool = kzalloc(sizeof(*pool), GFP_KERNEL);
    	if (!pool)
    		return ERR_PTR(-ENOMEM);
    
    	spin_lock_init(&pool->lock);
    	INIT_LIST_HEAD(&pool->free_slots);
    	INIT_LIST_HEAD(&pool->pending);
    
    	pool->slots = kcalloc(req->num_slots, sizeof(*slot), GFP_KERNEL);
    	if (!pool->slots) {
    		ret = -ENOMEM;
    		goto err_free_pool;
    	}
    
    	if (req->max_payload_len) {
    		pool->payload_buf = kcalloc(req->num_slots,
    					    req->max_payload_len, GFP_KERNEL);
    		if (!pool->payload_buf) {
    			ret = -ENOMEM;
    			goto err_free_pool;
    		}
    	}
    
    	for (i = 0; i < req->num_slots; i++) {
    		slot = &pool->slots[i];
    		i3c_master_init_ibi_slot(dev, &slot->base);
    
    		if (req->max_payload_len)
    			slot->base.data = pool->payload_buf +
    					  (i * req->max_payload_len);
    
    		list_add_tail(&slot->node, &pool->free_slots);
    		pool->num_slots++;
    	}
    
    	return pool;
    
    err_free_pool:
    	i3c_generic_ibi_free_pool(pool);
    	return ERR_PTR(ret);
    }
    EXPORT_SYMBOL_GPL(i3c_generic_ibi_alloc_pool);
    
    /**
     * i3c_generic_ibi_get_free_slot() - Get a free slot from a generic IBI pool
     * @pool: the pool to query an IBI slot on
     *
     * Search for a free slot in a generic IBI pool.
     * The slot should be returned to the pool using i3c_generic_ibi_recycle_slot()
     * when it's no longer needed.
     *
     * Return: a pointer to a free slot, or NULL if there's no free slot available.
     */
    struct i3c_ibi_slot *
    i3c_generic_ibi_get_free_slot(struct i3c_generic_ibi_pool *pool)
    {
    	struct i3c_generic_ibi_slot *slot;
    	unsigned long flags;
    
    	spin_lock_irqsave(&pool->lock, flags);
    	slot = list_first_entry_or_null(&pool->free_slots,
    					struct i3c_generic_ibi_slot, node);
    	if (slot)
    		list_del(&slot->node);
    	spin_unlock_irqrestore(&pool->lock, flags);
    
    	return slot ? &slot->base : NULL;
    }
    EXPORT_SYMBOL_GPL(i3c_generic_ibi_get_free_slot);
    
    /**
     * i3c_generic_ibi_recycle_slot() - Return a slot to a generic IBI pool
     * @pool: the pool to return the IBI slot to
     * @s: IBI slot to recycle
     *
     * Add an IBI slot back to its generic IBI pool. Should be called from the
     * master driver struct_master_controller_ops->recycle_ibi() method.
     */
    void i3c_generic_ibi_recycle_slot(struct i3c_generic_ibi_pool *pool,
    				  struct i3c_ibi_slot *s)
    {
    	struct i3c_generic_ibi_slot *slot;
    	unsigned long flags;
    
    	if (!s)
    		return;
    
    	slot = container_of(s, struct i3c_generic_ibi_slot, base);
    	spin_lock_irqsave(&pool->lock, flags);
    	list_add_tail(&slot->node, &pool->free_slots);
    	spin_unlock_irqrestore(&pool->lock, flags);
    }
    EXPORT_SYMBOL_GPL(i3c_generic_ibi_recycle_slot);
    
    static int i3c_master_check_ops(const struct i3c_master_controller_ops *ops)
    {
    	if (!ops || !ops->bus_init || !ops->priv_xfers ||
    	    !ops->send_ccc_cmd || !ops->do_daa || !ops->i2c_xfers)
    		return -EINVAL;
    
    	if (ops->request_ibi &&
    	    (!ops->enable_ibi || !ops->disable_ibi || !ops->free_ibi ||
    	     !ops->recycle_ibi_slot))
    		return -EINVAL;
    
    	return 0;
    }
    
    /**
     * i3c_master_register() - register an I3C master
     * @master: master used to send frames on the bus
     * @parent: the parent device (the one that provides this I3C master
     *	    controller)
     * @ops: the master controller operations
     * @secondary: true if you are registering a secondary master. Will return
     *	       -ENOTSUPP if set to true since secondary masters are not yet
     *	       supported
     *
     * This function takes care of everything for you:
     *
     * - creates and initializes the I3C bus
     * - populates the bus with static I2C devs if @parent->of_node is not
     *   NULL
     * - registers all I3C devices added by the controller during bus
     *   initialization
     * - registers the I2C adapter and all I2C devices
     *
     * Return: 0 in case of success, a negative error code otherwise.
     */
    int i3c_master_register(struct i3c_master_controller *master,
    			struct device *parent,
    			const struct i3c_master_controller_ops *ops,
    			bool secondary)
    {
    	unsigned long i2c_scl_rate = I3C_BUS_I2C_FM_PLUS_SCL_RATE;
    	struct i3c_bus *i3cbus = i3c_master_get_bus(master);
    	enum i3c_bus_mode mode = I3C_BUS_MODE_PURE;
    	struct i2c_dev_boardinfo *i2cbi;
    	int ret;
    
    	/* We do not support secondary masters yet. */
    	if (secondary)
    		return -ENOTSUPP;
    
    	ret = i3c_master_check_ops(ops);
    	if (ret)
    		return ret;
    
    	master->dev.parent = parent;
    	master->dev.of_node = of_node_get(parent->of_node);
    	master->dev.bus = &i3c_bus_type;
    	master->dev.type = &i3c_masterdev_type;
    	master->dev.release = i3c_masterdev_release;
    	master->ops = ops;
    	master->secondary = secondary;
    	INIT_LIST_HEAD(&master->boardinfo.i2c);
    	INIT_LIST_HEAD(&master->boardinfo.i3c);
    
    	ret = i3c_bus_init(i3cbus);
    	if (ret)
    		return ret;
    
    	device_initialize(&master->dev);
    	dev_set_name(&master->dev, "i3c-%d", i3cbus->id);
    
    	ret = of_populate_i3c_bus(master);
    	if (ret)
    		goto err_put_dev;
    
    	list_for_each_entry(i2cbi, &master->boardinfo.i2c, node) {
    		switch (i2cbi->lvr & I3C_LVR_I2C_INDEX_MASK) {
    		case I3C_LVR_I2C_INDEX(0):
    			if (mode < I3C_BUS_MODE_MIXED_FAST)
    				mode = I3C_BUS_MODE_MIXED_FAST;
    			break;
    		case I3C_LVR_I2C_INDEX(1):
    			if (mode < I3C_BUS_MODE_MIXED_LIMITED)
    				mode = I3C_BUS_MODE_MIXED_LIMITED;
    			break;
    		case I3C_LVR_I2C_INDEX(2):
    			if (mode < I3C_BUS_MODE_MIXED_SLOW)
    				mode = I3C_BUS_MODE_MIXED_SLOW;
    			break;
    		default:
    			ret = -EINVAL;
    			goto err_put_dev;
    		}
    
    		if (i2cbi->lvr & I3C_LVR_I2C_FM_MODE)
    			i2c_scl_rate = I3C_BUS_I2C_FM_SCL_RATE;
    	}
    
    	ret = i3c_bus_set_mode(i3cbus, mode, i2c_scl_rate);
    	if (ret)
    		goto err_put_dev;
    
    	master->wq = alloc_workqueue("%s", 0, 0, dev_name(parent));
    	if (!master->wq) {
    		ret = -ENOMEM;
    		goto err_put_dev;
    	}
    
    	ret = i3c_master_bus_init(master);
    	if (ret)
    		goto err_put_dev;
    
    	ret = device_add(&master->dev);
    	if (ret)
    		goto err_cleanup_bus;
    
    	/*
    	 * Expose our I3C bus as an I2C adapter so that I2C devices are exposed
    	 * through the I2C subsystem.
    	 */
    	ret = i3c_master_i2c_adapter_init(master);
    	if (ret)
    		goto err_del_dev;
    
    	/*
    	 * We're done initializing the bus and the controller, we can now
    	 * register I3C devices discovered during the initial DAA.
    	 */
    	master->init_done = true;
    	i3c_bus_normaluse_lock(&master->bus);
    	i3c_master_register_new_i3c_devs(master);
    	i3c_bus_normaluse_unlock(&master->bus);
    
    	return 0;
    
    err_del_dev:
    	device_del(&master->dev);
    
    err_cleanup_bus:
    	i3c_master_bus_cleanup(master);
    
    err_put_dev:
    	put_device(&master->dev);
    
    	return ret;
    }
    EXPORT_SYMBOL_GPL(i3c_master_register);
    
    /**
     * i3c_master_unregister() - unregister an I3C master
     * @master: master used to send frames on the bus
     *
     * Basically undo everything done in i3c_master_register().
     *
     * Return: 0 in case of success, a negative error code otherwise.
     */
    int i3c_master_unregister(struct i3c_master_controller *master)
    {
    	i3c_master_i2c_adapter_cleanup(master);
    	i3c_master_unregister_i3c_devs(master);
    	i3c_master_bus_cleanup(master);
    	device_unregister(&master->dev);
    
    	return 0;
    }
    EXPORT_SYMBOL_GPL(i3c_master_unregister);
    
    int i3c_dev_do_priv_xfers_locked(struct i3c_dev_desc *dev,
    				 struct i3c_priv_xfer *xfers,
    				 int nxfers)
    {
    	struct i3c_master_controller *master;
    
    	if (!dev)
    		return -ENOENT;
    
    	master = i3c_dev_get_master(dev);
    	if (!master || !xfers)
    		return -EINVAL;
    
    	if (!master->ops->priv_xfers)
    		return -ENOTSUPP;
    
    	return master->ops->priv_xfers(dev, xfers, nxfers);
    }
    
    int i3c_dev_disable_ibi_locked(struct i3c_dev_desc *dev)
    {
    	struct i3c_master_controller *master;
    	int ret;
    
    	if (!dev->ibi)
    		return -EINVAL;
    
    	master = i3c_dev_get_master(dev);
    	ret = master->ops->disable_ibi(dev);
    	if (ret)
    		return ret;
    
    	reinit_completion(&dev->ibi->all_ibis_handled);
    	if (atomic_read(&dev->ibi->pending_ibis))
    		wait_for_completion(&dev->ibi->all_ibis_handled);
    
    	dev->ibi->enabled = false;
    
    	return 0;
    }
    
    int i3c_dev_enable_ibi_locked(struct i3c_dev_desc *dev)
    {
    	struct i3c_master_controller *master = i3c_dev_get_master(dev);
    	int ret;
    
    	if (!dev->ibi)
    		return -EINVAL;
    
    	ret = master->ops->enable_ibi(dev);
    	if (!ret)
    		dev->ibi->enabled = true;
    
    	return ret;
    }
    
    int i3c_dev_request_ibi_locked(struct i3c_dev_desc *dev,
    			       const struct i3c_ibi_setup *req)
    {
    	struct i3c_master_controller *master = i3c_dev_get_master(dev);
    	struct i3c_device_ibi_info *ibi;
    	int ret;
    
    	if (!master->ops->request_ibi)
    		return -ENOTSUPP;
    
    	if (dev->ibi)
    		return -EBUSY;
    
    	ibi = kzalloc(sizeof(*ibi), GFP_KERNEL);
    	if (!ibi)
    		return -ENOMEM;
    
    	atomic_set(&ibi->pending_ibis, 0);
    	init_completion(&ibi->all_ibis_handled);
    	ibi->handler = req->handler;
    	ibi->max_payload_len = req->max_payload_len;
    	ibi->num_slots = req->num_slots;
    
    	dev->ibi = ibi;
    	ret = master->ops->request_ibi(dev, req);
    	if (ret) {
    		kfree(ibi);
    		dev->ibi = NULL;
    	}
    
    	return ret;
    }
    
    void i3c_dev_free_ibi_locked(struct i3c_dev_desc *dev)
    {
    	struct i3c_master_controller *master = i3c_dev_get_master(dev);
    
    	if (!dev->ibi)
    		return;
    
    	if (WARN_ON(dev->ibi->enabled))
    		WARN_ON(i3c_dev_disable_ibi_locked(dev));
    
    	master->ops->free_ibi(dev);
    	kfree(dev->ibi);
    	dev->ibi = NULL;
    }
    
    static int __init i3c_init(void)
    {
    	return bus_register(&i3c_bus_type);
    }
    subsys_initcall(i3c_init);
    
    static void __exit i3c_exit(void)
    {
    	idr_destroy(&i3c_bus_idr);
    	bus_unregister(&i3c_bus_type);
    }
    module_exit(i3c_exit);
    
    MODULE_AUTHOR("Boris Brezillon <boris.brezillon@bootlin.com>");
    MODULE_DESCRIPTION("I3C core");
    MODULE_LICENSE("GPL v2");