From 0231d00082f61cfe03f2b7c27e5356f8cdf0312c Mon Sep 17 00:00:00 2001 From: Prarit Bhargava Date: Thu, 18 Jan 2018 10:09:51 -0500 Subject: [PATCH] ACPI: SPCR: Make SPCR available to x86 SPCR is currently only enabled or ARM64 and x86 can use SPCR to setup an early console. General fixes include updating Documentation & Kconfig (for x86), updating comments, and changing parse_spcr() to acpi_parse_spcr(), and earlycon_init_is_deferred to earlycon_acpi_spcr_enable to be more descriptive. On x86, many systems have a valid SPCR table but the table version is not 2 so the table version check must be a warning. On ARM64 when the kernel parameter earlycon is used both the early console and console are enabled. On x86, only the earlycon should be enabled by by default. Modify acpi_parse_spcr() to allow options for initializing the early console and console separately. Signed-off-by: Prarit Bhargava Acked-by: Ingo Molnar Reviewed-by: Mark Salter Tested-by: Mark Salter Signed-off-by: Rafael J. Wysocki --- Documentation/admin-guide/kernel-parameters.txt | 9 +++++--- arch/arm64/kernel/acpi.c | 4 ++-- arch/x86/kernel/acpi/boot.c | 3 +++ drivers/acpi/Kconfig | 7 +++++- drivers/acpi/spcr.c | 29 +++++++++++++------------ drivers/tty/serial/earlycon.c | 15 +++++-------- include/linux/acpi.h | 7 ++++-- include/linux/serial_core.h | 4 ++-- 8 files changed, 44 insertions(+), 34 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 1bdcf57..aecb1c8 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -917,9 +917,12 @@ earlycon= [KNL] Output early console device and options. - When used with no options, the early console is - determined by the stdout-path property in device - tree's chosen node. + [ARM64] The early console is determined by the + stdout-path property in device tree's chosen node, + or determined by the ACPI SPCR table. + + [X86] When used with no options the early console is + determined by the ACPI SPCR table. cdns,[,options] Start an early, polled-mode console on a Cadence diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c index b316271..2aa5609 100644 --- a/arch/arm64/kernel/acpi.c +++ b/arch/arm64/kernel/acpi.c @@ -230,10 +230,10 @@ void __init acpi_boot_table_init(void) done: if (acpi_disabled) { - if (earlycon_init_is_deferred) + if (earlycon_acpi_spcr_enable) early_init_dt_scan_chosen_stdout(); } else { - parse_spcr(earlycon_init_is_deferred); + acpi_parse_spcr(earlycon_acpi_spcr_enable, true); if (IS_ENABLED(CONFIG_ACPI_BGRT)) acpi_table_parse(ACPI_SIG_BGRT, acpi_parse_bgrt); } diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c index ec3a286..2aa9209 100644 --- a/arch/x86/kernel/acpi/boot.c +++ b/arch/x86/kernel/acpi/boot.c @@ -36,6 +36,7 @@ #include #include #include +#include #include #include @@ -1625,6 +1626,8 @@ int __init acpi_boot_init(void) if (!acpi_noirq) x86_init.pci.init = pci_acpi_init; + /* Do not enable ACPI SPCR console by default */ + acpi_parse_spcr(earlycon_acpi_spcr_enable, false); return 0; } diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig index 4650539..ddcb5f4 100644 --- a/drivers/acpi/Kconfig +++ b/drivers/acpi/Kconfig @@ -79,7 +79,12 @@ config ACPI_DEBUGGER_USER endif config ACPI_SPCR_TABLE - bool + bool "ACPI Serial Port Console Redirection Support" + default y if X86 + help + Enable support for Serial Port Console Redirection (SPCR) Table. + This table provides information about the configuration of the + earlycon console. config ACPI_LPIT bool diff --git a/drivers/acpi/spcr.c b/drivers/acpi/spcr.c index 324b35bf..89e97d2 100644 --- a/drivers/acpi/spcr.c +++ b/drivers/acpi/spcr.c @@ -21,7 +21,7 @@ * occasionally getting stuck as 1. To avoid the potential for a hang, check * TXFE == 0 instead of BUSY == 1. This may not be suitable for all UART * implementations, so only do so if an affected platform is detected in - * parse_spcr(). + * acpi_parse_spcr(). */ bool qdf2400_e44_present; EXPORT_SYMBOL(qdf2400_e44_present); @@ -74,19 +74,21 @@ static bool xgene_8250_erratum_present(struct acpi_table_spcr *tb) } /** - * parse_spcr() - parse ACPI SPCR table and add preferred console + * acpi_parse_spcr() - parse ACPI SPCR table and add preferred console * - * @earlycon: set up earlycon for the console specified by the table + * @enable_earlycon: set up earlycon for the console specified by the table + * @enable_console: setup 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. + * console is registered and if @enable_earlycon is true, earlycon is set up. + * If @enable_console is true the system console is also configured. * * When CONFIG_ACPI_SPCR_TABLE is defined, this function should be called * from arch initialization code as soon as the DT/ACPI decision is made. * */ -int __init parse_spcr(bool earlycon) +int __init acpi_parse_spcr(bool enable_earlycon, bool enable_console) { static char opts[64]; struct acpi_table_spcr *table; @@ -105,11 +107,8 @@ int __init parse_spcr(bool earlycon) if (ACPI_FAILURE(status)) return -ENOENT; - if (table->header.revision < 2) { - err = -ENOENT; - pr_err("wrong table version\n"); - goto done; - } + if (table->header.revision < 2) + pr_info("SPCR table version %d\n", table->header.revision); if (table->serial_port.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) { switch (ACPI_ACCESS_BIT_WIDTH(( @@ -185,7 +184,7 @@ int __init parse_spcr(bool earlycon) */ if (qdf2400_erratum_44_present(&table->header)) { qdf2400_e44_present = true; - if (earlycon) + if (enable_earlycon) uart = "qdf2400_e44"; } @@ -205,11 +204,13 @@ int __init parse_spcr(bool earlycon) pr_info("console: %s\n", opts); - if (earlycon) + if (enable_earlycon) setup_earlycon(opts); - err = add_preferred_console(uart, 0, opts + strlen(uart) + 1); - + if (enable_console) + err = add_preferred_console(uart, 0, opts + strlen(uart) + 1); + else + err = 0; done: acpi_put_table((struct acpi_table_header *)table); return err; diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c index 4c8b80f..870e84f 100644 --- a/drivers/tty/serial/earlycon.c +++ b/drivers/tty/serial/earlycon.c @@ -197,25 +197,20 @@ int __init setup_earlycon(char *buf) } /* - * 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() + * This defers the initialization of the early console until after ACPI has + * been initialized. */ -bool earlycon_init_is_deferred __initdata; +bool earlycon_acpi_spcr_enable __initdata; /* early_param wrapper for setup_earlycon() */ static int __init param_setup_earlycon(char *buf) { int err; - /* - * Just 'earlycon' is a valid param for devicetree earlycons; - * don't generate a warning from parse_early_params() in that case - */ + /* Just 'earlycon' is a valid param for devicetree and ACPI SPCR. */ if (!buf || !buf[0]) { if (IS_ENABLED(CONFIG_ACPI_SPCR_TABLE)) { - earlycon_init_is_deferred = true; + earlycon_acpi_spcr_enable = true; return 0; } else if (!buf) { return early_init_dt_scan_chosen_stdout(); diff --git a/include/linux/acpi.h b/include/linux/acpi.h index b8f4c3c..e6b98a3 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -1249,9 +1249,12 @@ static inline bool acpi_has_watchdog(void) { return false; } #ifdef CONFIG_ACPI_SPCR_TABLE extern bool qdf2400_e44_present; -int parse_spcr(bool earlycon); +int acpi_parse_spcr(bool enable_earlycon, bool enable_console); #else -static inline int parse_spcr(bool earlycon) { return 0; } +static inline int acpi_parse_spcr(bool enable_earlycon, bool enable_console) +{ + return 0; +} #endif #if IS_ENABLED(CONFIG_ACPI_GENERIC_GSI) diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index 37b044e..aefd0e5 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -376,10 +376,10 @@ extern int of_setup_earlycon(const struct earlycon_id *match, const char *options); #ifdef CONFIG_SERIAL_EARLYCON -extern bool earlycon_init_is_deferred __initdata; +extern bool earlycon_acpi_spcr_enable __initdata; int setup_earlycon(char *buf); #else -static const bool earlycon_init_is_deferred; +static const bool earlycon_acpi_spcr_enable; static inline int setup_earlycon(char *buf) { return 0; } #endif -- 2.7.4