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26 results

cxl.h

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  • cros_ec_proto.c 15.43 KiB
    /*
     * ChromeOS EC communication protocol helper functions
     *
     * Copyright (C) 2015 Google, Inc
     *
     * This software is licensed under the terms of the GNU General Public
     * License version 2, as published by the Free Software Foundation, and
     * may be copied, distributed, and modified under those terms.
     *
     * This program is distributed in the hope that it will be useful,
     * but WITHOUT ANY WARRANTY; without even the implied warranty of
     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     * GNU General Public License for more details.
     *
     */
    
    #include <linux/mfd/cros_ec.h>
    #include <linux/delay.h>
    #include <linux/device.h>
    #include <linux/module.h>
    #include <linux/slab.h>
    #include <asm/unaligned.h>
    
    #define EC_COMMAND_RETRIES	50
    
    static int prepare_packet(struct cros_ec_device *ec_dev,
    			  struct cros_ec_command *msg)
    {
    	struct ec_host_request *request;
    	u8 *out;
    	int i;
    	u8 csum = 0;
    
    	BUG_ON(ec_dev->proto_version != EC_HOST_REQUEST_VERSION);
    	BUG_ON(msg->outsize + sizeof(*request) > ec_dev->dout_size);
    
    	out = ec_dev->dout;
    	request = (struct ec_host_request *)out;
    	request->struct_version = EC_HOST_REQUEST_VERSION;
    	request->checksum = 0;
    	request->command = msg->command;
    	request->command_version = msg->version;
    	request->reserved = 0;
    	request->data_len = msg->outsize;
    
    	for (i = 0; i < sizeof(*request); i++)
    		csum += out[i];
    
    	/* Copy data and update checksum */
    	memcpy(out + sizeof(*request), msg->data, msg->outsize);
    	for (i = 0; i < msg->outsize; i++)
    		csum += msg->data[i];
    
    	request->checksum = -csum;
    
    	return sizeof(*request) + msg->outsize;
    }
    
    static int send_command(struct cros_ec_device *ec_dev,
    			struct cros_ec_command *msg)
    {
    	int ret;
    	int (*xfer_fxn)(struct cros_ec_device *ec, struct cros_ec_command *msg);
    
    	if (ec_dev->proto_version > 2)
    		xfer_fxn = ec_dev->pkt_xfer;
    	else
    		xfer_fxn = ec_dev->cmd_xfer;
    
    	ret = (*xfer_fxn)(ec_dev, msg);
    	if (msg->result == EC_RES_IN_PROGRESS) {
    		int i;
    		struct cros_ec_command *status_msg;
    		struct ec_response_get_comms_status *status;
    
    		status_msg = kmalloc(sizeof(*status_msg) + sizeof(*status),
    				     GFP_KERNEL);
    		if (!status_msg)
    			return -ENOMEM;
    
    		status_msg->version = 0;
    		status_msg->command = EC_CMD_GET_COMMS_STATUS;
    		status_msg->insize = sizeof(*status);
    		status_msg->outsize = 0;
    
    		/*
    		 * Query the EC's status until it's no longer busy or
    		 * we encounter an error.
    		 */
    		for (i = 0; i < EC_COMMAND_RETRIES; i++) {
    			usleep_range(10000, 11000);
    
    			ret = (*xfer_fxn)(ec_dev, status_msg);
    			if (ret == -EAGAIN)
    				continue;
    			if (ret < 0)
    				break;
    
    			msg->result = status_msg->result;
    			if (status_msg->result != EC_RES_SUCCESS)
    				break;
    
    			status = (struct ec_response_get_comms_status *)
    				 status_msg->data;
    			if (!(status->flags & EC_COMMS_STATUS_PROCESSING))
    				break;
    		}
    
    		kfree(status_msg);
    	}
    
    	return ret;
    }
    
    int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
    		       struct cros_ec_command *msg)
    {
    	u8 *out;
    	u8 csum;
    	int i;
    
    	if (ec_dev->proto_version > 2)
    		return prepare_packet(ec_dev, msg);
    
    	BUG_ON(msg->outsize > EC_PROTO2_MAX_PARAM_SIZE);
    	out = ec_dev->dout;
    	out[0] = EC_CMD_VERSION0 + msg->version;
    	out[1] = msg->command;
    	out[2] = msg->outsize;
    	csum = out[0] + out[1] + out[2];
    	for (i = 0; i < msg->outsize; i++)
    		csum += out[EC_MSG_TX_HEADER_BYTES + i] = msg->data[i];
    	out[EC_MSG_TX_HEADER_BYTES + msg->outsize] = csum;
    
    	return EC_MSG_TX_PROTO_BYTES + msg->outsize;
    }
    EXPORT_SYMBOL(cros_ec_prepare_tx);
    
    int cros_ec_check_result(struct cros_ec_device *ec_dev,
    			 struct cros_ec_command *msg)
    {
    	switch (msg->result) {
    	case EC_RES_SUCCESS:
    		return 0;
    	case EC_RES_IN_PROGRESS:
    		dev_dbg(ec_dev->dev, "command 0x%02x in progress\n",
    			msg->command);
    		return -EAGAIN;
    	default:
    		dev_dbg(ec_dev->dev, "command 0x%02x returned %d\n",
    			msg->command, msg->result);
    		return 0;
    	}
    }
    EXPORT_SYMBOL(cros_ec_check_result);
    
    /*
     * cros_ec_get_host_event_wake_mask
     *
     * Get the mask of host events that cause wake from suspend.
     *
     * @ec_dev: EC device to call
     * @msg: message structure to use
     * @mask: result when function returns >=0.
     *
     * LOCKING:
     * the caller has ec_dev->lock mutex, or the caller knows there is
     * no other command in progress.
     */
    static int cros_ec_get_host_event_wake_mask(struct cros_ec_device *ec_dev,
    					    struct cros_ec_command *msg,
    					    uint32_t *mask)
    {
    	struct ec_response_host_event_mask *r;
    	int ret;
    
    	msg->command = EC_CMD_HOST_EVENT_GET_WAKE_MASK;
    	msg->version = 0;
    	msg->outsize = 0;
    	msg->insize = sizeof(*r);
    
    	ret = send_command(ec_dev, msg);
    	if (ret > 0) {
    		r = (struct ec_response_host_event_mask *)msg->data;
    		*mask = r->mask;
    	}
    
    	return ret;
    }
    
    static int cros_ec_host_command_proto_query(struct cros_ec_device *ec_dev,
    					    int devidx,
    					    struct cros_ec_command *msg)
    {
    	/*
    	 * Try using v3+ to query for supported protocols. If this
    	 * command fails, fall back to v2. Returns the highest protocol
    	 * supported by the EC.
    	 * Also sets the max request/response/passthru size.
    	 */
    	int ret;
    
    	if (!ec_dev->pkt_xfer)
    		return -EPROTONOSUPPORT;
    
    	memset(msg, 0, sizeof(*msg));
    	msg->command = EC_CMD_PASSTHRU_OFFSET(devidx) | EC_CMD_GET_PROTOCOL_INFO;
    	msg->insize = sizeof(struct ec_response_get_protocol_info);
    
    	ret = send_command(ec_dev, msg);
    
    	if (ret < 0) {
    		dev_dbg(ec_dev->dev,
    			"failed to check for EC[%d] protocol version: %d\n",
    			devidx, ret);
    		return ret;
    	}
    
    	if (devidx > 0 && msg->result == EC_RES_INVALID_COMMAND)
    		return -ENODEV;
    	else if (msg->result != EC_RES_SUCCESS)
    		return msg->result;
    
    	return 0;
    }
    
    static int cros_ec_host_command_proto_query_v2(struct cros_ec_device *ec_dev)
    {
    	struct cros_ec_command *msg;
    	struct ec_params_hello *hello_params;
    	struct ec_response_hello *hello_response;
    	int ret;
    	int len = max(sizeof(*hello_params), sizeof(*hello_response));
    
    	msg = kmalloc(sizeof(*msg) + len, GFP_KERNEL);
    	if (!msg)
    		return -ENOMEM;
    
    	msg->version = 0;
    	msg->command = EC_CMD_HELLO;
    	hello_params = (struct ec_params_hello *)msg->data;
    	msg->outsize = sizeof(*hello_params);
    	hello_response = (struct ec_response_hello *)msg->data;
    	msg->insize = sizeof(*hello_response);
    
    	hello_params->in_data = 0xa0b0c0d0;
    
    	ret = send_command(ec_dev, msg);
    
    	if (ret < 0) {
    		dev_dbg(ec_dev->dev,
    			"EC failed to respond to v2 hello: %d\n",
    			ret);
    		goto exit;
    	} else if (msg->result != EC_RES_SUCCESS) {
    		dev_err(ec_dev->dev,
    			"EC responded to v2 hello with error: %d\n",
    			msg->result);
    		ret = msg->result;
    		goto exit;
    	} else if (hello_response->out_data != 0xa1b2c3d4) {
    		dev_err(ec_dev->dev,
    			"EC responded to v2 hello with bad result: %u\n",
    			hello_response->out_data);
    		ret = -EBADMSG;
    		goto exit;
    	}
    
    	ret = 0;
    
     exit:
    	kfree(msg);
    	return ret;
    }
    
    /*
     * cros_ec_get_host_command_version_mask
     *
     * Get the version mask of a given command.
     *
     * @ec_dev: EC device to call
     * @msg: message structure to use
     * @cmd: command to get the version of.
     * @mask: result when function returns 0.
     *
     * @return 0 on success, error code otherwise
     *
     * LOCKING:
     * the caller has ec_dev->lock mutex or the caller knows there is
     * no other command in progress.
     */
    static int cros_ec_get_host_command_version_mask(struct cros_ec_device *ec_dev,
    	u16 cmd, u32 *mask)
    {
    	struct ec_params_get_cmd_versions *pver;
    	struct ec_response_get_cmd_versions *rver;
    	struct cros_ec_command *msg;
    	int ret;
    
    	msg = kmalloc(sizeof(*msg) + max(sizeof(*rver), sizeof(*pver)),
    		      GFP_KERNEL);
    	if (!msg)
    		return -ENOMEM;
    
    	msg->version = 0;
    	msg->command = EC_CMD_GET_CMD_VERSIONS;
    	msg->insize = sizeof(*rver);
    	msg->outsize = sizeof(*pver);
    
    	pver = (struct ec_params_get_cmd_versions *)msg->data;
    	pver->cmd = cmd;
    
    	ret = send_command(ec_dev, msg);
    	if (ret > 0) {
    		rver = (struct ec_response_get_cmd_versions *)msg->data;
    		*mask = rver->version_mask;
    	}
    
    	kfree(msg);
    
    	return ret;
    }
    
    int cros_ec_query_all(struct cros_ec_device *ec_dev)
    {
    	struct device *dev = ec_dev->dev;
    	struct cros_ec_command *proto_msg;
    	struct ec_response_get_protocol_info *proto_info;
    	u32 ver_mask = 0;
    	int ret;
    
    	proto_msg = kzalloc(sizeof(*proto_msg) + sizeof(*proto_info),
    			    GFP_KERNEL);
    	if (!proto_msg)
    		return -ENOMEM;
    
    	/* First try sending with proto v3. */
    	ec_dev->proto_version = 3;
    	ret = cros_ec_host_command_proto_query(ec_dev, 0, proto_msg);
    
    	if (ret == 0) {
    		proto_info = (struct ec_response_get_protocol_info *)
    			proto_msg->data;
    		ec_dev->max_request = proto_info->max_request_packet_size -
    			sizeof(struct ec_host_request);
    		ec_dev->max_response = proto_info->max_response_packet_size -
    			sizeof(struct ec_host_response);
    		ec_dev->proto_version =
    			min(EC_HOST_REQUEST_VERSION,
    					fls(proto_info->protocol_versions) - 1);
    		dev_dbg(ec_dev->dev,
    			"using proto v%u\n",
    			ec_dev->proto_version);
    
    		ec_dev->din_size = ec_dev->max_response +
    			sizeof(struct ec_host_response) +
    			EC_MAX_RESPONSE_OVERHEAD;
    		ec_dev->dout_size = ec_dev->max_request +
    			sizeof(struct ec_host_request) +
    			EC_MAX_REQUEST_OVERHEAD;
    
    		/*
    		 * Check for PD
    		 */
    		ret = cros_ec_host_command_proto_query(ec_dev, 1, proto_msg);
    
    		if (ret) {
    			dev_dbg(ec_dev->dev, "no PD chip found: %d\n", ret);
    			ec_dev->max_passthru = 0;
    		} else {
    			dev_dbg(ec_dev->dev, "found PD chip\n");
    			ec_dev->max_passthru =
    				proto_info->max_request_packet_size -
    				sizeof(struct ec_host_request);
    		}
    	} else {
    		/* Try querying with a v2 hello message. */
    		ec_dev->proto_version = 2;
    		ret = cros_ec_host_command_proto_query_v2(ec_dev);
    
    		if (ret == 0) {
    			/* V2 hello succeeded. */
    			dev_dbg(ec_dev->dev, "falling back to proto v2\n");
    
    			ec_dev->max_request = EC_PROTO2_MAX_PARAM_SIZE;
    			ec_dev->max_response = EC_PROTO2_MAX_PARAM_SIZE;
    			ec_dev->max_passthru = 0;
    			ec_dev->pkt_xfer = NULL;
    			ec_dev->din_size = EC_PROTO2_MSG_BYTES;
    			ec_dev->dout_size = EC_PROTO2_MSG_BYTES;
    		} else {
    			/*
    			 * It's possible for a test to occur too early when
    			 * the EC isn't listening. If this happens, we'll
    			 * test later when the first command is run.
    			 */
    			ec_dev->proto_version = EC_PROTO_VERSION_UNKNOWN;
    			dev_dbg(ec_dev->dev, "EC query failed: %d\n", ret);
    			goto exit;
    		}
    	}
    
    	devm_kfree(dev, ec_dev->din);
    	devm_kfree(dev, ec_dev->dout);
    
    	ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL);
    	if (!ec_dev->din) {
    		ret = -ENOMEM;
    		goto exit;
    	}
    
    	ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL);
    	if (!ec_dev->dout) {
    		devm_kfree(dev, ec_dev->din);
    		ret = -ENOMEM;
    		goto exit;
    	}
    
    	/* Probe if MKBP event is supported */
    	ret = cros_ec_get_host_command_version_mask(ec_dev,
    						    EC_CMD_GET_NEXT_EVENT,
    						    &ver_mask);
    	if (ret < 0 || ver_mask == 0)
    		ec_dev->mkbp_event_supported = 0;
    	else
    		ec_dev->mkbp_event_supported = 1;
    
    	/*
    	 * Get host event wake mask, assume all events are wake events
    	 * if unavailable.
    	 */
    	ret = cros_ec_get_host_event_wake_mask(ec_dev, proto_msg,
    					       &ec_dev->host_event_wake_mask);
    	if (ret < 0)
    		ec_dev->host_event_wake_mask = U32_MAX;
    
    	ret = 0;
    
    exit:
    	kfree(proto_msg);
    	return ret;
    }
    EXPORT_SYMBOL(cros_ec_query_all);
    
    int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
    		     struct cros_ec_command *msg)
    {
    	int ret;
    
    	mutex_lock(&ec_dev->lock);
    	if (ec_dev->proto_version == EC_PROTO_VERSION_UNKNOWN) {
    		ret = cros_ec_query_all(ec_dev);
    		if (ret) {
    			dev_err(ec_dev->dev,
    				"EC version unknown and query failed; aborting command\n");
    			mutex_unlock(&ec_dev->lock);
    			return ret;
    		}
    	}
    
    	if (msg->insize > ec_dev->max_response) {
    		dev_dbg(ec_dev->dev, "clamping message receive buffer\n");
    		msg->insize = ec_dev->max_response;
    	}
    
    	if (msg->command < EC_CMD_PASSTHRU_OFFSET(1)) {
    		if (msg->outsize > ec_dev->max_request) {
    			dev_err(ec_dev->dev,
    				"request of size %u is too big (max: %u)\n",
    				msg->outsize,
    				ec_dev->max_request);
    			mutex_unlock(&ec_dev->lock);
    			return -EMSGSIZE;
    		}
    	} else {
    		if (msg->outsize > ec_dev->max_passthru) {
    			dev_err(ec_dev->dev,
    				"passthru rq of size %u is too big (max: %u)\n",
    				msg->outsize,
    				ec_dev->max_passthru);
    			mutex_unlock(&ec_dev->lock);
    			return -EMSGSIZE;
    		}
    	}
    	ret = send_command(ec_dev, msg);
    	mutex_unlock(&ec_dev->lock);
    
    	return ret;
    }
    EXPORT_SYMBOL(cros_ec_cmd_xfer);
    
    int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
    			    struct cros_ec_command *msg)
    {
    	int ret;
    
    	ret = cros_ec_cmd_xfer(ec_dev, msg);
    	if (ret < 0) {
    		dev_err(ec_dev->dev, "Command xfer error (err:%d)\n", ret);
    	} else if (msg->result != EC_RES_SUCCESS) {
    		dev_dbg(ec_dev->dev, "Command result (err: %d)\n", msg->result);
    		return -EPROTO;
    	}
    
    	return ret;
    }
    EXPORT_SYMBOL(cros_ec_cmd_xfer_status);
    
    static int get_next_event_xfer(struct cros_ec_device *ec_dev,
    			       struct cros_ec_command *msg,
    			       int version, uint32_t size)
    {
    	int ret;
    
    	msg->version = version;
    	msg->command = EC_CMD_GET_NEXT_EVENT;
    	msg->insize = size;
    	msg->outsize = 0;
    
    	ret = cros_ec_cmd_xfer(ec_dev, msg);
    	if (ret > 0) {
    		ec_dev->event_size = ret - 1;
    		memcpy(&ec_dev->event_data, msg->data, ret);
    	}
    
    	return ret;
    }
    
    static int get_next_event(struct cros_ec_device *ec_dev)
    {
    	u8 buffer[sizeof(struct cros_ec_command) + sizeof(ec_dev->event_data)];
    	struct cros_ec_command *msg = (struct cros_ec_command *)&buffer;
    	static int cmd_version = 1;
    	int ret;
    
    	if (ec_dev->suspended) {
    		dev_dbg(ec_dev->dev, "Device suspended.\n");
    		return -EHOSTDOWN;
    	}
    
    	if (cmd_version == 1) {
    		ret = get_next_event_xfer(ec_dev, msg, cmd_version,
    				sizeof(struct ec_response_get_next_event_v1));
    		if (ret < 0 || msg->result != EC_RES_INVALID_VERSION)
    			return ret;
    
    		/* Fallback to version 0 for future send attempts */
    		cmd_version = 0;
    	}
    
    	ret = get_next_event_xfer(ec_dev, msg, cmd_version,
    				  sizeof(struct ec_response_get_next_event));
    
    	return ret;
    }
    
    static int get_keyboard_state_event(struct cros_ec_device *ec_dev)
    {
    	u8 buffer[sizeof(struct cros_ec_command) +
    		  sizeof(ec_dev->event_data.data)];
    	struct cros_ec_command *msg = (struct cros_ec_command *)&buffer;
    
    	msg->version = 0;
    	msg->command = EC_CMD_MKBP_STATE;
    	msg->insize = sizeof(ec_dev->event_data.data);
    	msg->outsize = 0;
    
    	ec_dev->event_size = cros_ec_cmd_xfer(ec_dev, msg);
    	ec_dev->event_data.event_type = EC_MKBP_EVENT_KEY_MATRIX;
    	memcpy(&ec_dev->event_data.data, msg->data,
    	       sizeof(ec_dev->event_data.data));
    
    	return ec_dev->event_size;
    }
    
    int cros_ec_get_next_event(struct cros_ec_device *ec_dev, bool *wake_event)
    {
    	u8 event_type;
    	u32 host_event;
    	int ret;
    
    	if (!ec_dev->mkbp_event_supported) {
    		ret = get_keyboard_state_event(ec_dev);
    		if (ret <= 0)
    			return ret;
    
    		if (wake_event)
    			*wake_event = true;
    
    		return ret;
    	}
    
    	ret = get_next_event(ec_dev);
    	if (ret <= 0)
    		return ret;
    
    	if (wake_event) {
    		event_type = ec_dev->event_data.event_type;
    		host_event = cros_ec_get_host_event(ec_dev);
    
    		/*
    		 * Sensor events need to be parsed by the sensor sub-device.
    		 * Defer them, and don't report the wakeup here.
    		 */
    		if (event_type == EC_MKBP_EVENT_SENSOR_FIFO)
    			*wake_event = false;
    		/* Masked host-events should not count as wake events. */
    		else if (host_event &&
    			 !(host_event & ec_dev->host_event_wake_mask))
    			*wake_event = false;
    		/* Consider all other events as wake events. */
    		else
    			*wake_event = true;
    	}
    
    	return ret;
    }
    EXPORT_SYMBOL(cros_ec_get_next_event);
    
    u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev)
    {
    	u32 host_event;
    
    	BUG_ON(!ec_dev->mkbp_event_supported);
    
    	if (ec_dev->event_data.event_type != EC_MKBP_EVENT_HOST_EVENT)
    		return 0;
    
    	if (ec_dev->event_size != sizeof(host_event)) {
    		dev_warn(ec_dev->dev, "Invalid host event size\n");
    		return 0;
    	}
    
    	host_event = get_unaligned_le32(&ec_dev->event_data.data.host_event);
    
    	return host_event;
    }
    EXPORT_SYMBOL(cros_ec_get_host_event);