'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.
Parse this table and check if any registered console match the description. If it does, enable that console. Introduce a new function acpi_console_check(). At the uart port registration, this function checks if the ACPI SPCR table specifies its argument of type struct uart_port to be a console and if so calls add_preferred_console(). [1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.den0044a/index.html [2] http://msdn.microsoft.com/en-us/library/windows/hardware/dn639131(v=vs.85).aspx Signed-off-by: Aleksey Makarov <[email protected]> --- drivers/acpi/Kconfig | 3 + drivers/acpi/Makefile | 1 + drivers/acpi/spcr.c | 116 +++++++++++++++++++++++++++++++++++++++ drivers/tty/serial/serial_core.c | 14 ++++- include/linux/acpi.h | 10 ++++ 5 files changed, 142 insertions(+), 2 deletions(-) create mode 100644 drivers/acpi/spcr.c diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig index 65fb483..5611eb6 100644 --- a/drivers/acpi/Kconfig +++ b/drivers/acpi/Kconfig @@ -77,6 +77,9 @@ config ACPI_DEBUGGER_USER endif +config ACPI_SPCR_TABLE + bool + config ACPI_SLEEP bool depends on SUSPEND || HIBERNATION diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile index 7395928..f70ae14 100644 --- a/drivers/acpi/Makefile +++ b/drivers/acpi/Makefile @@ -82,6 +82,7 @@ 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 diff --git a/drivers/acpi/spcr.c b/drivers/acpi/spcr.c new file mode 100644 index 0000000..c460cb1 --- /dev/null +++ b/drivers/acpi/spcr.c @@ -0,0 +1,116 @@ +/* + * 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> + +static char *options; +static struct acpi_generic_address address; + +static int __init parse_spcr_init(void) +{ + struct acpi_table_spcr *table; + acpi_size table_size; + acpi_status status; + int err = 0; + + status = acpi_get_table_with_size(ACPI_SIG_SPCR, 0, + (struct acpi_table_header **)&table, + &table_size); + + if (ACPI_FAILURE(status)) { + pr_err("could not get the table\n"); + return -ENOENT; + } + + if (table->header.revision < 2) { + err = -EINVAL; + pr_err("wrong table version\n"); + goto done; + } + + switch (table->baud_rate) { + case 3: + options = "9600"; + break; + case 4: + options = "19200"; + break; + case 6: + options = "57600"; + break; + case 7: + options = "115200"; + break; + default: + options = ""; + break; + } + + address = table->serial_port; + +done: + early_acpi_os_unmap_memory((void __iomem *)table, table_size); + return err; +} + +/* + * This function calls __init parse_spcr_init() so it needs __ref. + * It is referenced by the arch_inicall() macros so it will be called + * at initialization and the 'parsed' variable will be set. + * So it's safe to make it __ref. + */ +static int __ref parse_spcr(void) +{ + static bool parsed; + static int parse_error; + + if (!parsed) { + parse_error = parse_spcr_init(); + parsed = true; + } + + return parse_error; +} + +arch_initcall(parse_spcr); + +/** + * acpi_console_check - Check if uart matches the console specified by SPCR. + * + * @uport: uart port to check + * + * This function checks if the ACPI SPCR table specifies @uport to be a console + * and if so calls add_preferred_console() + * + * Return: a non-error value if the console matches. + */ +bool acpi_console_check(struct uart_port *uport) +{ + if (acpi_disabled || console_set_on_cmdline || parse_spcr() < 0) + return false; + + if ((address.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY && + address.address == (u64)uport->mapbase) || + (address.space_id == ACPI_ADR_SPACE_SYSTEM_IO && + address.address == (u64)uport->iobase)) { + pr_info("adding preferred console [%s%d]\n", uport->cons->name, + uport->line); + add_preferred_console(uport->cons->name, uport->line, options); + return true; + } + + return false; +} diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index a126a60..459ab54 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -34,6 +34,7 @@ #include <linux/serial_core.h> #include <linux/delay.h> #include <linux/mutex.h> +#include <linux/acpi.h> #include <asm/irq.h> #include <asm/uaccess.h> @@ -2654,8 +2655,17 @@ int uart_add_one_port(struct uart_driver *drv, struct uart_port *uport) spin_lock_init(&uport->lock); lockdep_set_class(&uport->lock, &port_lock_key); } - if (uport->cons && uport->dev) - of_console_check(uport->dev->of_node, uport->cons->name, uport->line); + + /* + * Support both open FW and ACPI access to console definitions. + * Both of_console_check() and acpi_console_check() will call + * add_preferred_console() if a console definition is found. + */ + if (uport->cons && uport->dev) { + if (!acpi_console_check(uport)) + of_console_check(uport->dev->of_node, uport->cons->name, + uport->line); + } uart_configure_port(drv, state, uport); diff --git a/include/linux/acpi.h b/include/linux/acpi.h index 06ed7e5..ea0c297 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -1004,4 +1004,14 @@ static inline struct fwnode_handle *acpi_get_next_subnode(struct device *dev, #define acpi_probe_device_table(t) ({ int __r = 0; __r;}) #endif +struct uart_port; +#ifdef CONFIG_ACPI_SPCR_TABLE +bool acpi_console_check(struct uart_port *uport); +#else +static inline bool acpi_console_check(struct uart_port *uport) +{ + return FALSE; +} +#endif + #endif /*_LINUX_ACPI_H*/ -- 2.7.1
