Commit 0231d000 authored by Prarit Bhargava's avatar Prarit Bhargava Committed by Rafael J. Wysocki

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: default avatarPrarit Bhargava <prarit@redhat.com>
Acked-by: default avatarIngo Molnar <mingo@kernel.org>
Reviewed-by: default avatarMark Salter <msalter@redhat.com>
Tested-by: default avatarMark Salter <msalter@redhat.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 89067434
......@@ -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,<addr>[,options]
Start an early, polled-mode console on a Cadence
......
......@@ -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);
}
......
......@@ -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>
......@@ -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;
}
......
......@@ -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
......
......@@ -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;
......
......@@ -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();
......
......@@ -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)
......
......@@ -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
......
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