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SubjectRe: [PATCH v9 09/21] ARM64 / ACPI: Introduce early_param "acpi=" to enable/disable ACPI
Date
On Wed, 25 Feb 2015 16:39:49 +0800
, Hanjun Guo <hanjun.guo@linaro.org>
wrote:
> From: Al Stone <al.stone@linaro.org>
>
> This implements the following policy to decide whether ACPI should
> be used to boot the system:
> - acpi=off: ACPI will not be used to boot the system, even if there is
> no alternative available (e.g., device tree is empty)
> - acpi=force: only ACPI will be used to boot the system; if that fails,
> there will be no fallback to alternative methods (such as device tree)
> - otherwise, ACPI will be used as a fallback if the device tree turns out
> to lack a platform description; the heuristic to decide this is whether
> /chosen is the only node present at depth 1
>
> CC: Catalin Marinas <catalin.marinas@arm.com>
> CC: Will Deacon <will.deacon@arm.com>
> CC: Rafael J. Wysocki <rjw@rjwysocki.net>
> Signed-off-by: Al Stone <al.stone@linaro.org>
> Signed-off-by: Graeme Gregory <graeme.gregory@linaro.org>
> Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

Acked-by: Grant Likely <grant.likely@linaro.org>

> ---
> Documentation/kernel-parameters.txt | 3 ++-
> arch/arm64/include/asm/acpi.h | 7 +++++
> arch/arm64/kernel/acpi.c | 52 +++++++++++++++++++++++++++++++++----
> 3 files changed, 56 insertions(+), 6 deletions(-)
>
> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> index bfcb1a6..d6c35a7 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,ARM64]
> 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 "acpi=off" or "acpi=force" are available
>
> See also Documentation/power/runtime_pm.txt, pci=noacpi
>
> diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
> index 40e0924..c5a9b97 100644
> --- a/arch/arm64/include/asm/acpi.h
> +++ b/arch/arm64/include/asm/acpi.h
> @@ -39,6 +39,13 @@ static inline void disable_acpi(void)
> acpi_noirq = 1;
> }
>
> +static inline void enable_acpi(void)
> +{
> + acpi_disabled = 0;
> + acpi_pci_disabled = 0;
> + acpi_noirq = 0;
> +}
> +
> /*
> * It's used from ACPI core in kdump to boot UP system with SMP kernel,
> * with this check the ACPI core will not override the CPU index
> diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
> index f052e7a..bdcc9fc 100644
> --- a/arch/arm64/kernel/acpi.c
> +++ b/arch/arm64/kernel/acpi.c
> @@ -22,15 +22,49 @@
> #include <linux/irq.h>
> #include <linux/irqdomain.h>
> #include <linux/memblock.h>
> +#include <linux/of_fdt.h>
> #include <linux/smp.h>
>
> -int acpi_noirq; /* skip ACPI IRQ initialization */
> -int acpi_disabled;
> +int acpi_noirq = 1; /* skip ACPI IRQ initialization */
> +int acpi_disabled = 1;
> EXPORT_SYMBOL(acpi_disabled);
>
> -int acpi_pci_disabled; /* skip ACPI PCI scan and IRQ initialization */
> +int acpi_pci_disabled = 1; /* skip ACPI PCI scan and IRQ initialization */
> EXPORT_SYMBOL(acpi_pci_disabled);
>
> +static bool __initdata param_acpi_off;
> +static bool __initdata param_acpi_force;
> +
> +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)
> + param_acpi_off = true;
> + else if (strcmp(arg, "force") == 0) /* force ACPI to be enabled */
> + param_acpi_force = true;
> + else
> + return -EINVAL; /* Core will print when we return error */
> +
> + return 0;
> +}
> +early_param("acpi", parse_acpi);
> +
> +static int __init dt_scan_depth1_nodes(unsigned long node,
> + const char *uname, int depth,
> + void *data)
> +{
> + /*
> + * Return 1 as soon as we encounter a node at depth 1 that is
> + * not the /chosen node.
> + */
> + if (depth == 1 && (strcmp(uname, "chosen") != 0))
> + return 1;
> + return 0;
> +}
> +
> /*
> * __acpi_map_table() will be called before page_init(), so early_ioremap()
> * or early_memremap() should be called here to for ACPI table mapping.
> @@ -83,10 +117,18 @@ static int __init acpi_parse_fadt(struct acpi_table_header *table)
> */
> void __init acpi_boot_table_init(void)
> {
> - /* If acpi_disabled, bail out */
> - if (acpi_disabled)
> + /*
> + * Enable ACPI instead of device tree unless
> + * - ACPI has been disabled explicitly (acpi=off), or
> + * - the device tree is not empty (it has more than just a /chosen node)
> + * and ACPI has not been force enabled (acpi=force)
> + */
> + if (param_acpi_off ||
> + (!param_acpi_force && of_scan_flat_dt(dt_scan_depth1_nodes, NULL)))
> return;
>
> + enable_acpi();
> +
> /* Initialize the ACPI boot-time table parser. */
> if (acpi_table_init()) {
> disable_acpi();
> --
> 1.9.1
>



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