| Message ID | 20180118150951.28964-1-prarit@redhat.com (mailing list archive) |
|---|---|
| State | Changes Requested, archived |
| Headers | show |
* Prarit Bhargava <prarit@redhat.com> wrote: > Note on testing: I've tested this on several ARM64 and x86 boxes (only > earlycon, console=ttyS0,115200, and with both options), verified that > functionality on ARM64 has not changed (ie, CONFIG_ACPI_SPCR_TABLE is > always =y), and verified functionality when !CONFIG_ACPI_SPCR_TABLE on > x86. > > P. > > ----8<---- > > 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 <prarit@redhat.com> > Cc: linux-acpi@vger.kernel.org > Cc: linux-doc@vger.kernel.org > Cc: linux-arm-kernel@lists.infradead.org > Cc: linux-pm@vger.kernel.org > Cc: linux-serial@vger.kernel.org > Cc: Bhupesh Sharma <bhsharma@redhat.com> > Cc: Lv Zheng <lv.zheng@intel.com> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Ingo Molnar <mingo@redhat.com> > Cc: "H. Peter Anvin" <hpa@zytor.com> > Cc: x86@kernel.org > Cc: Jonathan Corbet <corbet@lwn.net> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Will Deacon <will.deacon@arm.com> > Cc: "Rafael J. Wysocki" Mrjw@rjwysocki.net> > Cc: Timur Tabi <timur@codeaurora.org> > Cc: graeme.gregory@linaro.org > Cc: mark.salter@redhat.com > --- > 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(-) I'm fine with the x86 aspect of this: Acked-by: Ingo Molnar <mingo@kernel.org> > 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. s/in device tree's chosen node /in the device tree's chosen node Thanks, Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, 2018-01-18 at 10:09 -0500, Prarit Bhargava wrote: > Note on testing: I've tested this on several ARM64 and x86 boxes (only > earlycon, console=ttyS0,115200, and with both options), verified that > functionality on ARM64 has not changed (ie, CONFIG_ACPI_SPCR_TABLE is > always =y), and verified functionality when !CONFIG_ACPI_SPCR_TABLE on > x86. > > P. > > ----8<---- > > 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 <prarit@redhat.com> > Cc: linux-acpi@vger.kernel.org > Cc: linux-doc@vger.kernel.org > Cc: linux-arm-kernel@lists.infradead.org > Cc: linux-pm@vger.kernel.org > Cc: linux-serial@vger.kernel.org > Cc: Bhupesh Sharma <bhsharma@redhat.com> > Cc: Lv Zheng <lv.zheng@intel.com> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Ingo Molnar <mingo@redhat.com> > Cc: "H. Peter Anvin" <hpa@zytor.com> > Cc: x86@kernel.org > Cc: Jonathan Corbet <corbet@lwn.net> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Will Deacon <will.deacon@arm.com> > Cc: "Rafael J. Wysocki" Mrjw@rjwysocki.net> > Cc: Timur Tabi <timur@codeaurora.org> > Cc: graeme.gregory@linaro.org > Cc: mark.salter@redhat.com > --- > 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 46b26bfee27b..6f519230ed34 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -915,9 +915,12 @@ > > 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,<addr>[,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 b3162715ed78..2aa5609def27 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 f4c463df8b08..0bf6a58f7a6d 100644 > --- a/arch/x86/kernel/acpi/boot.c > +++ b/arch/x86/kernel/acpi/boot.c > @@ -36,6 +36,7 @@ > #include <linux/ioport.h> > #include <linux/pci.h> > #include <linux/efi-bgrt.h> > +#include <linux/serial_core.h> > > #include <asm/e820/api.h> > #include <asm/irqdomain.h> > @@ -1626,6 +1627,8 @@ 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 46505396869e..ddcb5f40e8ee 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 324b35bfe781..89e97d21a89c 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 4c8b80f1c688..870e84fb6e39 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 dc1ebfeeb5ec..9aac8f0ebe23 100644 > --- a/include/linux/acpi.h > +++ b/include/linux/acpi.h > @@ -1242,9 +1242,12 @@ static inline void acpi_table_upgrade(void) { } > > #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 37b044e78333..aefd0e5115da 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 > This looks okay to me. Tested on a variety of arm64 platforms. Reviewed-by: Mark Salter <msalter@redhat.com> Tested-by: Mark Salter <msalter@redhat.com> -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 01/18/2018 09:09 AM, Prarit Bhargava wrote: > if (acpi_disabled) { > - if (earlycon_init_is_deferred) > + if (earlycon_acpi_spcr_enable) This patch works for me, so I can ACK it, but first you might want to rename earlycon_acpi_spcr_enable, because these two lines don't make much sense. "If ACPI is disabled, and ACPI SCPR is enabled, then ...." If ACPI is disabled, then how can a variable called "earlycon_acpi_spcr_enable" be true? Would it make more sense to rename it to earlycon_spcr_enable?
On 01/22/2018 04:49 PM, Timur Tabi wrote: > On 01/18/2018 09:09 AM, Prarit Bhargava wrote: >> if (acpi_disabled) { >> - if (earlycon_init_is_deferred) >> + if (earlycon_acpi_spcr_enable) > > This patch works for me, so I can ACK it, but first you might want to rename > earlycon_acpi_spcr_enable, because these two lines don't make much sense. > > "If ACPI is disabled, and ACPI SCPR is enabled, then ...." > > If ACPI is disabled, then how can a variable called "earlycon_acpi_spcr_enable" > be true? > > Would it make more sense to rename it to earlycon_spcr_enable? > acpi_disabled is a global runtime flag that can be set via "acpi=off" on the command line. It does not disable the tables, only the reading and interpreting of the data in the tables. P. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Jan 18, 2018 at 10:09:51AM -0500, Prarit Bhargava wrote: > config ACPI_SPCR_TABLE > + 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. I just got asked this by oldconfig, which left me rather puzzled, WTF does this do? -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 02/12/2018 08:34 AM, Peter Zijlstra wrote: > On Thu, Jan 18, 2018 at 10:09:51AM -0500, Prarit Bhargava wrote: >> config ACPI_SPCR_TABLE >> + 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. > > I just got asked this by oldconfig, which left me rather puzzled, WTF > does this do? Odd -- I thought I had taken care of that :( My apologies Peter. ACPI SPCR is used by a vendor to define the serial console for a system. If SPCR exists a user can add kernel parameter "earlycon" (no extra kernel parameters) and the console will work out-of-the-box. The serial console configuration varies from vendor to vendor. This takes the guess-work out of defining a serial console. P. > -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 2/12/18 7:47 AM, Prarit Bhargava wrote: > ACPI SPCR is used by a vendor to define the serial console for a system. If > SPCR exists a user can add kernel parameter "earlycon" (no extra kernel > parameters) and the console will work out-of-the-box. "earlycon" is needed only for an *early* console. You don't need any command line parameters for a normal console to work with SPCR.
On 02/12/2018 09:43 AM, Timur Tabi wrote: > On 2/12/18 7:47 AM, Prarit Bhargava wrote: >> ACPI SPCR is used by a vendor to define the serial console for a system. If >> SPCR exists a user can add kernel parameter "earlycon" (no extra kernel >> parameters) and the console will work out-of-the-box. > > "earlycon" is needed only for an *early* console. You don't need any command > line parameters for a normal console to work with SPCR. That's true on ARM64. I specifically did not enable the console by default on x86. There are users who do not want a console active during boot & runtime. P. > -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Feb 12, 2018 at 08:47:57AM -0500, Prarit Bhargava wrote: > > > On 02/12/2018 08:34 AM, Peter Zijlstra wrote: > > On Thu, Jan 18, 2018 at 10:09:51AM -0500, Prarit Bhargava wrote: > >> config ACPI_SPCR_TABLE > >> + 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. > > > > I just got asked this by oldconfig, which left me rather puzzled, WTF > > does this do? > > Odd -- I thought I had taken care of that :( My apologies Peter. > > ACPI SPCR is used by a vendor to define the serial console for a system. If > SPCR exists a user can add kernel parameter "earlycon" (no extra kernel > parameters) and the console will work out-of-the-box. > > The serial console configuration varies from vendor to vendor. This takes the > guess-work out of defining a serial console. But when I specify "earlyprintk=serial,ttyS0,115200" this SPCR crud will not interfere? -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 2/12/18 8:49 AM, Prarit Bhargava wrote: > That's true on ARM64. I specifically did not enable the console by default on > x86. There are users who do not want a console active during boot & runtime. Hmmmm... That's a good point. On ARM systems with SPCR, you get a console whether you like it or not.
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 46b26bfee27b..6f519230ed34 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -915,9 +915,12 @@ 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,<addr>[,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 b3162715ed78..2aa5609def27 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 f4c463df8b08..0bf6a58f7a6d 100644 --- a/arch/x86/kernel/acpi/boot.c +++ b/arch/x86/kernel/acpi/boot.c @@ -36,6 +36,7 @@ #include <linux/ioport.h> #include <linux/pci.h> #include <linux/efi-bgrt.h> +#include <linux/serial_core.h> #include <asm/e820/api.h> #include <asm/irqdomain.h> @@ -1626,6 +1627,8 @@ 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 46505396869e..ddcb5f40e8ee 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 324b35bfe781..89e97d21a89c 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 4c8b80f1c688..870e84fb6e39 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 dc1ebfeeb5ec..9aac8f0ebe23 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -1242,9 +1242,12 @@ static inline void acpi_table_upgrade(void) { } #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 37b044e78333..aefd0e5115da 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
Note on testing: I've tested this on several ARM64 and x86 boxes (only earlycon, console=ttyS0,115200, and with both options), verified that functionality on ARM64 has not changed (ie, CONFIG_ACPI_SPCR_TABLE is always =y), and verified functionality when !CONFIG_ACPI_SPCR_TABLE on x86. P. ----8<---- 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 <prarit@redhat.com> Cc: linux-acpi@vger.kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-pm@vger.kernel.org Cc: linux-serial@vger.kernel.org Cc: Bhupesh Sharma <bhsharma@redhat.com> Cc: Lv Zheng <lv.zheng@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: x86@kernel.org Cc: Jonathan Corbet <corbet@lwn.net> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: "Rafael J. Wysocki" Mrjw@rjwysocki.net> Cc: Timur Tabi <timur@codeaurora.org> Cc: graeme.gregory@linaro.org Cc: mark.salter@redhat.com --- 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(-)