Commit ad1696f6 authored by Aleksey Makarov's avatar Aleksey Makarov Committed by Greg Kroah-Hartman

ACPI: parse SPCR and enable matching console

'ARM Server Base Boot Requiremets' [1] mentions SPCR (Serial Port
Console Redirection Table) [2] as a mandatory ACPI table that
specifies the configuration of serial console.

Defer initialization of DT earlycon until ACPI/DT decision is made.

Parse the ACPI SPCR table, setup earlycon if required,
enable specified console.

Thanks to Peter Hurley for explaining how this should work.

[1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.den0044a/index.html
[2] https://msdn.microsoft.com/en-us/library/windows/hardware/dn639132(v=vs.85).aspxSigned-off-by: default avatarAleksey Makarov <aleksey.makarov@linaro.org>
Acked-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: default avatarPeter Hurley <peter@hurleysoftware.com>
Tested-by: default avatarKefeng Wang <wangkefeng.wang@huawei.com>
Tested-by: default avatarChristopher Covington <cov@codeaurora.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent d503187b
......@@ -77,6 +77,9 @@ config ACPI_DEBUGGER_USER
endif
config ACPI_SPCR_TABLE
bool
config ACPI_SLEEP
bool
depends on SUSPEND || HIBERNATION
......
......@@ -81,6 +81,7 @@ obj-$(CONFIG_ACPI_EC_DEBUGFS) += ec_sys.o
obj-$(CONFIG_ACPI_CUSTOM_METHOD)+= custom_method.o
obj-$(CONFIG_ACPI_BGRT) += bgrt.o
obj-$(CONFIG_ACPI_CPPC_LIB) += cppc_acpi.o
obj-$(CONFIG_ACPI_SPCR_TABLE) += spcr.o
obj-$(CONFIG_ACPI_DEBUGGER_USER) += acpi_dbg.o
# processor has its own "processor." module_param namespace
......
/*
* Copyright (c) 2012, Intel Corporation
* Copyright (c) 2015, Red Hat, Inc.
* Copyright (c) 2015, 2016 Linaro Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#define pr_fmt(fmt) "ACPI: SPCR: " fmt
#include <linux/acpi.h>
#include <linux/console.h>
#include <linux/kernel.h>
#include <linux/serial_core.h>
/**
* parse_spcr() - parse ACPI SPCR table and add preferred console
*
* @earlycon: set up earlycon for the console specified by the table
*
* For the architectures with support for ACPI, CONFIG_ACPI_SPCR_TABLE may be
* defined to parse ACPI SPCR table. As a result of the parsing preferred
* console is registered and if @earlycon is true, earlycon is set up.
*
* When CONFIG_ACPI_SPCR_TABLE is defined, this function should be called
* from arch inintialization code as soon as the DT/ACPI decision is made.
*
*/
int __init parse_spcr(bool earlycon)
{
static char opts[64];
struct acpi_table_spcr *table;
acpi_size table_size;
acpi_status status;
char *uart;
char *iotype;
int baud_rate;
int err;
if (acpi_disabled)
return -ENODEV;
status = acpi_get_table_with_size(ACPI_SIG_SPCR, 0,
(struct acpi_table_header **)&table,
&table_size);
if (ACPI_FAILURE(status))
return -ENOENT;
if (table->header.revision < 2) {
err = -ENOENT;
pr_err("wrong table version\n");
goto done;
}
iotype = table->serial_port.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY ?
"mmio" : "io";
switch (table->interface_type) {
case ACPI_DBG2_ARM_SBSA_32BIT:
iotype = "mmio32";
/* fall through */
case ACPI_DBG2_ARM_PL011:
case ACPI_DBG2_ARM_SBSA_GENERIC:
case ACPI_DBG2_BCM2835:
uart = "pl011";
break;
case ACPI_DBG2_16550_COMPATIBLE:
case ACPI_DBG2_16550_SUBSET:
uart = "uart";
break;
default:
err = -ENOENT;
goto done;
}
switch (table->baud_rate) {
case 3:
baud_rate = 9600;
break;
case 4:
baud_rate = 19200;
break;
case 6:
baud_rate = 57600;
break;
case 7:
baud_rate = 115200;
break;
default:
err = -ENOENT;
goto done;
}
snprintf(opts, sizeof(opts), "%s,%s,0x%llx,%d", uart, iotype,
table->serial_port.address, baud_rate);
pr_info("console: %s\n", opts);
if (earlycon)
setup_earlycon(opts);
err = add_preferred_console(uart, 0, opts + strlen(uart) + 1);
done:
early_acpi_os_unmap_memory((void __iomem *)table, table_size);
return err;
}
......@@ -21,6 +21,7 @@
#include <linux/sizes.h>
#include <linux/of.h>
#include <linux/of_fdt.h>
#include <linux/acpi.h>
#ifdef CONFIG_FIX_EARLYCON_MEM
#include <asm/fixmap.h>
......@@ -198,6 +199,14 @@ int __init setup_earlycon(char *buf)
return -ENOENT;
}
/*
* When CONFIG_ACPI_SPCR_TABLE is defined, "earlycon" without parameters in
* command line does not start DT earlycon immediately, instead it defers
* starting it until DT/ACPI decision is made. At that time if ACPI is enabled
* call parse_spcr(), else call early_init_dt_scan_chosen_stdout()
*/
bool earlycon_init_is_deferred __initdata;
/* early_param wrapper for setup_earlycon() */
static int __init param_setup_earlycon(char *buf)
{
......@@ -207,8 +216,14 @@ static int __init param_setup_earlycon(char *buf)
* Just 'earlycon' is a valid param for devicetree earlycons;
* don't generate a warning from parse_early_params() in that case
*/
if (!buf || !buf[0])
return early_init_dt_scan_chosen_stdout();
if (!buf || !buf[0]) {
if (IS_ENABLED(CONFIG_ACPI_SPCR_TABLE)) {
earlycon_init_is_deferred = true;
return 0;
} else {
return early_init_dt_scan_chosen_stdout();
}
}
err = setup_earlycon(buf);
if (err == -ENOENT || err == -EALREADY)
......
......@@ -1074,4 +1074,10 @@ void acpi_table_upgrade(void);
static inline void acpi_table_upgrade(void) { }
#endif
#ifdef CONFIG_ACPI_SPCR_TABLE
int parse_spcr(bool earlycon);
#else
static inline int parse_spcr(bool earlycon) { return 0; }
#endif
#endif /*_LINUX_ACPI_H*/
......@@ -367,11 +367,18 @@ extern const struct earlycon_id __earlycon_table_end[];
#define EARLYCON_DECLARE(_name, fn) OF_EARLYCON_DECLARE(_name, "", fn)
extern int setup_earlycon(char *buf);
extern int of_setup_earlycon(const struct earlycon_id *match,
unsigned long node,
const char *options);
#ifdef CONFIG_SERIAL_EARLYCON
extern bool earlycon_init_is_deferred __initdata;
int setup_earlycon(char *buf);
#else
static const bool earlycon_init_is_deferred;
static inline int setup_earlycon(char *buf) { return 0; }
#endif
struct uart_port *uart_get_console(struct uart_port *ports, int nr,
struct console *c);
int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
......
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