[PATCH v4 06/13] ARM64 / ACPI: Introduce early_param for "acpi"

From: Hanjun Guo
Date: Thu Jun 26 2014 - 23:51:39 EST


From: Al Stone <al.stone@xxxxxxxxxx>

Introduce two early parameters for "acpi", one is the parameter
to disable ACPI on ARM64 and another one is acpi=strict to disable
out-of-spec workarounds.

Reviewed-by: Grant Likely <grant.likely@xxxxxxxxxx>
Signed-off-by: Al Stone <al.stone@xxxxxxxxxx>
Signed-off-by: Graeme Gregory <graeme.gregory@xxxxxxxxxx>
Signed-off-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
---
Documentation/kernel-parameters.txt | 3 ++-
drivers/acpi/plat/arm-core.c | 21 +++++++++++++++++++++
2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 8849049..b7e9fc0 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -165,7 +165,7 @@ multipliers 'Kilo', 'Mega', and 'Giga', equalling 2^10, 2^20, and 2^30
bytes respectively. Such letter suffixes can also be entirely omitted.


- acpi= [HW,ACPI,X86]
+ acpi= [HW,ACPI,X86,ARM]
Advanced Configuration and Power Interface
Format: { force | off | strict | noirq | rsdt }
force -- enable ACPI if default was off
@@ -175,6 +175,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
strictly ACPI specification compliant.
rsdt -- prefer RSDT over (default) XSDT
copy_dsdt -- copy DSDT to memory
+ For ARM64, ONLY "off" and "strict" are available.

See also Documentation/power/runtime_pm.txt, pci=noacpi

diff --git a/drivers/acpi/plat/arm-core.c b/drivers/acpi/plat/arm-core.c
index c6c7e03..cf46c25 100644
--- a/drivers/acpi/plat/arm-core.c
+++ b/drivers/acpi/plat/arm-core.c
@@ -108,3 +108,24 @@ void __init acpi_boot_table_init(void)
return;
}
}
+
+static int __init parse_acpi(char *arg)
+{
+ if (!arg)
+ return -EINVAL;
+
+ /* "acpi=off" disables both ACPI table parsing and interpreter */
+ if (strcmp(arg, "off") == 0) {
+ disable_acpi();
+ }
+ /* acpi=strict disables out-of-spec workarounds */
+ else if (strcmp(arg, "strict") == 0) {
+ acpi_strict = 1;
+ } else {
+ /* Core will printk when we return error */
+ return -EINVAL;
+ }
+
+ return 0;
+}
+early_param("acpi", parse_acpi);
--
1.7.9.5

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