On Mon, Feb 15, 2016 at 09:05:26PM +0300, Aleksey Makarov wrote: > '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 <aleksey.makarov@xxxxxxxxxx> > --- > drivers/acpi/Kconfig | 3 ++ > drivers/acpi/Makefile | 1 + > drivers/acpi/spcr.c | 97 ++++++++++++++++++++++++++++++++++++++++ > drivers/tty/serial/serial_core.c | 14 +++++- > include/linux/acpi.h | 10 +++++ > 5 files changed, 123 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 346101c..708b143 100644 > --- a/drivers/acpi/Makefile > +++ b/drivers/acpi/Makefile > @@ -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 > diff --git a/drivers/acpi/spcr.c b/drivers/acpi/spcr.c > new file mode 100644 > index 0000000..a1eca91 > --- /dev/null > +++ b/drivers/acpi/spcr.c > @@ -0,0 +1,97 @@ > +/* > + * 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 int acpi_table_parse_spcr(int (*handler)(struct acpi_table_spcr *table, > + void *data), void *data) > +{ > + struct acpi_table_spcr *table = NULL; Hi Alexey, Few minor comments... Are you sure you need thin initialization? > + acpi_size table_size; > + acpi_status status; > + int err; > + > + status = acpi_get_table_with_size(ACPI_SIG_SPCR, 0, > + (struct acpi_table_header **)&table, > + &table_size); > + > + if (ACPI_FAILURE(status)) > + return -ENODEV; > + > + err = handler(table, data); > + > + early_acpi_os_unmap_memory(table, table_size); > + > + return err; > +} > + > +static int spcr_table_handler_check(struct acpi_table_spcr *table, void *data) The name of function is not clear for me. You're not only checking here, but also adding console. > +{ > + struct uart_port *uport = data; > + char *options; > + > + if (table->header.revision < 2) > + return -EOPNOTSUPP; > + > + switch (table->baud_rate) { You don't need 'options' if your big condition returns false, so you can evaluate it inside conditional block. > + case 3: > + options = "9600"; > + break; > + case 4: > + options = "19200"; > + break; > + case 6: > + options = "57600"; > + break; > + case 7: > + options = "115200"; > + break; > + default: > + options = ""; > + break; 'break' isnot needed here > + } > + > + if ((table->serial_port.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY && Nitpick: just for better readability, I'd split it onto a set of separated checks: foo() { if (!cond1) return 0; if (!cond2) return 0; ... switch () { case 1: ... case 2: ... case 3: ... default: ... } return 1; } > + table->serial_port.address == (u64)uport->mapbase) || > + (table->serial_port.space_id == ACPI_ADR_SPACE_SYSTEM_IO && > + table->serial_port.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 1; > + > + } > + > + return 0; > +} > + > +/** > + * 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) > + return false; > + > + return acpi_table_parse_spcr(spcr_table_handler_check, uport) > 0; > +} > 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 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
