On Mon, Jan 25, 2016 at 05:45:22PM +0600, Aleksey Makarov wrote: > 'ARM Server Base Boot Requiremets' [1] mention 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. > > To implement that, introduce a new member > int (*acpi_match)(struct console *, struct acpi_table_spcr *) > of struct console. It allows drivers to check if they provide > a matching console device. >
Fails to compile on x86 kernel/built-in.o: In function `register_console': (.text+0x48cba): undefined reference to `console_acpi_match' Makefile:929: recipe for target 'vmlinux' failed make: *** [vmlinux] Error 1 Because CONFIG_ACPI_SPCR_TABLE is never set. Graeme > [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.maka...@linaro.org> > --- > arch/arm64/Kconfig | 1 + > drivers/acpi/Kconfig | 3 ++ > drivers/acpi/Makefile | 1 + > drivers/acpi/spcr.c | 85 > +++++++++++++++++++++++++++++++++++++++++++++++++ > include/linux/console.h | 12 +++++++ > kernel/printk/printk.c | 82 +++++++++++++++++++++++++++++++++++++---------- > 6 files changed, 167 insertions(+), 17 deletions(-) > create mode 100644 drivers/acpi/spcr.c > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 573bebc..bf31e3c 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -4,6 +4,7 @@ config ARM64 > select ACPI_GENERIC_GSI if ACPI > select ACPI_PCI_HOST_GENERIC if ACPI > select ACPI_REDUCED_HARDWARE_ONLY if ACPI > + select ACPI_SPCR_TABLE if ACPI > select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE > select ARCH_HAS_ELF_RANDOMIZE > select ARCH_HAS_GCOV_PROFILE_ALL > diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig > index e315061..142a338 100644 > --- a/drivers/acpi/Kconfig > +++ b/drivers/acpi/Kconfig > @@ -60,6 +60,9 @@ config ACPI_CCA_REQUIRED > config IORT_TABLE > bool > > +config ACPI_SPCR_TABLE > + bool > + > config ACPI_DEBUGGER > bool "AML debugger interface (EXPERIMENTAL)" > select ACPI_DEBUG > diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile > index 265eb90..8316859 100644 > --- a/drivers/acpi/Makefile > +++ b/drivers/acpi/Makefile > @@ -81,6 +81,7 @@ obj-$(CONFIG_ACPI_CUSTOM_METHOD)+= custom_method.o > obj-$(CONFIG_ACPI_BGRT) += bgrt.o > obj-$(CONFIG_ACPI_CPPC_LIB) += cppc_acpi.o > obj-$(CONFIG_IORT_TABLE) += iort.o > +obj-$(CONFIG_ACPI_SPCR_TABLE) += spcr.o > > # processor has its own "processor." module_param namespace > processor-y := processor_driver.o > diff --git a/drivers/acpi/spcr.c b/drivers/acpi/spcr.c > new file mode 100644 > index 0000000..ccb19a0 > --- /dev/null > +++ b/drivers/acpi/spcr.c > @@ -0,0 +1,85 @@ > +/* > + * 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> > + > +static struct acpi_table_spcr *spcr_table; > + > +int console_acpi_match(struct console *c, char **options) > +{ > + int err; > + > + if (!c->acpi_match) > + return -ENODEV; > + > + if (!spcr_table) > + return -EAGAIN; > + > + err = c->acpi_match(c, spcr_table); > + if (err < 0) > + return err; > + > + if (options) { > + switch (spcr_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; > + } > + } > + > + return err; > +} > + > +static int __init spcr_table_detect(void) > +{ > + struct acpi_table_header *table; > + acpi_status status; > + > + if (acpi_disabled) > + return -ENODEV; > + > + status = acpi_get_table(ACPI_SIG_SPCR, 0, &table); > + if (ACPI_FAILURE(status)) { > + const char *msg = acpi_format_exception(status); > + > + pr_err("Failed to get table, %s\n", msg); > + return -EINVAL; > + } > + > + if (table->revision < 2) > + return -EOPNOTSUPP; > + > + spcr_table = (struct acpi_table_spcr *)table; > + > + pr_info("Console at 0x%016llx\n", spcr_table->serial_port.address); > + > + acpi_register_consoles_try_again(); > + > + return 0; > +} > + > +arch_initcall(spcr_table_detect); > diff --git a/include/linux/console.h b/include/linux/console.h > index bd19434..94d0bd8 100644 > --- a/include/linux/console.h > +++ b/include/linux/console.h > @@ -117,6 +117,7 @@ static inline int con_debug_leave(void) > #define CON_BRL (32) /* Used for a braille device */ > #define CON_EXTENDED (64) /* Use the extended output format a la /dev/kmsg */ > > +struct acpi_table_spcr; > struct console { > char name[16]; > void (*write)(struct console *, const char *, unsigned); > @@ -125,6 +126,7 @@ struct console { > void (*unblank)(void); > int (*setup)(struct console *, char *); > int (*match)(struct console *, char *name, int idx, char *options); > + int (*acpi_match)(struct console *, struct acpi_table_spcr *); > short flags; > short index; > int cflag; > @@ -132,6 +134,16 @@ struct console { > struct console *next; > }; > > +#ifdef CONFIG_ACPI > +int console_acpi_match(struct console *c, char **options); > +#else > +static inline int console_acpi_match(struct console *c, char **options) > +{ > + return -ENODEV; > +} > +#endif > +void acpi_register_consoles_try_again(void); > + > /* > * for_each_console() allows you to iterate on each console > */ > diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c > index 37e531f..3cf8cba 100644 > --- a/kernel/printk/printk.c > +++ b/kernel/printk/printk.c > @@ -2430,6 +2430,25 @@ static int __init keep_bootcon_setup(char *str) > > early_param("keep_bootcon", keep_bootcon_setup); > > +static DEFINE_MUTEX(acpi_consoles_delayed_mutex); > +static struct console *acpi_consoles_delayed; > + > +void acpi_register_consoles_try_again(void) > +{ > + mutex_lock(&acpi_consoles_delayed_mutex); > + while (acpi_consoles_delayed) { > + > + struct console *c = acpi_consoles_delayed; > + > + acpi_consoles_delayed = acpi_consoles_delayed->next; > + > + mutex_unlock(&acpi_consoles_delayed_mutex); > + register_console(c); > + mutex_lock(&acpi_consoles_delayed_mutex); > + } > + mutex_unlock(&acpi_consoles_delayed_mutex); > +} > + > /* > * The console driver calls this routine during kernel initialization > * to register the console printing procedure with printk() and to > @@ -2538,8 +2557,30 @@ void register_console(struct console *newcon) > break; > } > > - if (!(newcon->flags & CON_ENABLED)) > - return; > + if (!(newcon->flags & CON_ENABLED)) { > + char *opts; > + int err; > + > + if (newcon->index < 0) > + newcon->index = 0; > + > + err = console_acpi_match(newcon, &opts); > + > + if (err == -EAGAIN) { > + mutex_lock(&acpi_consoles_delayed_mutex); > + newcon->next = acpi_consoles_delayed; > + acpi_consoles_delayed = newcon; > + mutex_unlock(&acpi_consoles_delayed_mutex); > + return; > + } else if (err < 0) { > + return; > + } else { > + if (newcon->setup && newcon->setup(newcon, opts) != 0) > + return; > + newcon->flags |= CON_ENABLED | CON_CONSDEV; > + preferred_console = true; > + } > + } > > /* > * If we have a bootconsole, and are switching to a real console, > @@ -2612,34 +2653,41 @@ void register_console(struct console *newcon) > } > EXPORT_SYMBOL(register_console); > > +static int delete_from_console_list(struct console **list, struct console *c) > +{ > + while (*list) { > + struct console *cur = *list; > + > + if (cur == c) { > + *list = cur->next; > + return 0; > + } > + list = &cur->next; > + } > + return 1; > +} > + > int unregister_console(struct console *console) > { > - struct console *a, *b; > int res; > > pr_info("%sconsole [%s%d] disabled\n", > (console->flags & CON_BOOT) ? "boot" : "" , > console->name, console->index); > > + mutex_lock(&acpi_consoles_delayed_mutex); > + res = delete_from_console_list(&acpi_consoles_delayed, console); > + mutex_unlock(&acpi_consoles_delayed_mutex); > + if (res == 0) > + return res; > + > res = _braille_unregister_console(console); > if (res) > return res; > > - res = 1; > console_lock(); > - if (console_drivers == console) { > - console_drivers=console->next; > - res = 0; > - } else if (console_drivers) { > - for (a=console_drivers->next, b=console_drivers ; > - a; b=a, a=b->next) { > - if (a == console) { > - b->next = a->next; > - res = 0; > - break; > - } > - } > - } > + > + res = delete_from_console_list(&console_drivers, console); > > if (!res && (console->flags & CON_EXTENDED)) > nr_ext_console_drivers--; > -- > 2.7.0 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-ker...@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
