[PATCH v8 3/4] ARM64: ACPI: enable ACPI_SPCR_TABLE

Aleksey Makarov
2016-05-20T13:03:22Z

SBBR mentions SPCR as a mandatory ACPI table. So enable it for ARM64

Earlycon should be set up as early as possible. ACPI boot tables are
mapped in arch/arm64/kernel/acpi.c:acpi_boot_table_init() that
is called from setup_arch() and that's where we parse SPCR.
So it has to be opted-in per-arch.

When ACPI_SPCR_TABLE is defined initialization of DT earlycon is
deferred until the DT/ACPI decision is done. Initialize DT earlycon
if ACPI is disabled.

Signed-off-by: Aleksey Makarov <aleksey.makarov@linaro.org>
Tested-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
arch/arm64/Kconfig | 1 +
arch/arm64/kernel/acpi.c | 11 ++++++++++-
2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 5d30abf..80c0816 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_DEVMEM_IS_ALLOWED
select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
select ARCH_HAS_ELF_RANDOMIZE
diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
index 3e4f1a4..252a6d9 100644
--- a/arch/arm64/kernel/acpi.c
+++ b/arch/arm64/kernel/acpi.c
@@ -24,6 +24,7 @@
#include <linux/memblock.h>
#include <linux/of_fdt.h>
#include <linux/smp.h>
+#include <linux/serial_core.h>

#include <asm/cputype.h>
#include <asm/cpu_ops.h>
@@ -206,7 +207,7 @@ void __init acpi_boot_table_init(void)
if (param_acpi_off ||
(!param_acpi_on && !param_acpi_force &&
of_scan_flat_dt(dt_scan_depth1_nodes, NULL)))
- return;
+ goto done;

/*
* ACPI is disabled at this point. Enable it in order to parse
@@ -226,6 +227,14 @@ void __init acpi_boot_table_init(void)
if (!param_acpi_force)
disable_acpi();
}
+
+done:
+ if (acpi_disabled) {
+ if (earlycon_init_is_deferred)
+ early_init_dt_scan_chosen_stdout();
+ } else {
+ parse_spcr(earlycon_init_is_deferred);
+ }
}

#ifdef CONFIG_ACPI_APEI
--
2.8.2