Re: [PATCH v2 05/18] ARM64 / ACPI: Parse FADT table to get PSCI flags for PSCI init

[Sudeep Holla <sudeep.holla@arm.com>]

On 04/08/14 16:28, Hanjun Guo wrote:
> There are two flags: PSCI_COMPLIANT and PSCI_USE_HVC. When set,
> the former signals to the OS that the hardware is PSCI compliant.
> The latter selects the appropriate conduit for PSCI calls by
> toggling between Hypervisor Calls (HVC) and Secure Monitor Calls
> (SMC).
>
> FADT table contains such information, parse FADT to get the flags
> for PSCI init. Since ACPI 5.1 doesn't support self defined PSCI
> function IDs, which means that only PSCI 0.2+ is supported in ACPI.
>
> At the same time, only ACPI 5.1 or higher verison supports PSCI,
> and FADT Major.Minor version was introduced in ACPI 5.1, so we
> will check the version and only parse FADT table with version >= 5.1.
>
> If firmware provides ACPI tables with ACPI version less than 5.1,
> OS will be messed up with those information and have no way to
> bring up secondery CPUs, so disable ACPI if we get an FADT table
> with version less that 5.1.
>
> Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
> Signed-off-by: Graeme Gregory <graeme.gregory@linaro.org>
> ---
>   arch/arm64/include/asm/acpi.h |   12 ++++++
>   arch/arm64/kernel/acpi.c      |   37 +++++++++++++++++
>   arch/arm64/kernel/psci.c      |   89 ++++++++++++++++++++++++++++++-----------
>   arch/arm64/kernel/setup.c     |    2 +
>   4 files changed, 117 insertions(+), 23 deletions(-)
>
> diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
> index 6400312..6e04868 100644
> --- a/arch/arm64/include/asm/acpi.h
> +++ b/arch/arm64/include/asm/acpi.h
> @@ -19,6 +19,18 @@ extern int acpi_disabled;
>   extern int acpi_noirq;
>   extern int acpi_pci_disabled;
>
> +/* 1 to indicate PSCI 0.2+ is implemented */
> +static inline bool acpi_psci_present(void)
> +{
> +	return !!(acpi_gbl_FADT.arm_boot_flags & ACPI_FADT_PSCI_COMPLIANT);
> +}
> +
> +/* 1 to indicate HVC must be used instead of SMC as the PSCI conduit */
> +static inline bool acpi_psci_use_hvc(void)
> +{
> +	return !!(acpi_gbl_FADT.arm_boot_flags & ACPI_FADT_PSCI_USE_HVC);
> +}
> +
>   static inline void disable_acpi(void)
>   {
>   	acpi_disabled = 1;
> diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
> index 9cf9127..69a315d 100644
> --- a/arch/arm64/kernel/acpi.c
> +++ b/arch/arm64/kernel/acpi.c
> @@ -11,6 +11,8 @@
>    *  published by the Free Software Foundation.
>    */
>
> +#define pr_fmt(fmt) "ACPI: " fmt
> +
>   #include <linux/init.h>
>   #include <linux/acpi.h>
>   #include <linux/cpumask.h>
> @@ -47,6 +49,26 @@ void __init __acpi_unmap_table(char *map, unsigned long size)
>   	early_memunmap(map, size);
>   }
>
> +static int __init acpi_parse_fadt(struct acpi_table_header *table)
> +{
> +	struct acpi_table_fadt *fadt = (struct acpi_table_fadt *)table;
> +
> +	/*
> +	 * Revision in table header is the FADT Major version,
> +	 * and there is a minor version of FADT which was introduced
> +	 * by ACPI 5.1, we only deal with ACPI 5.1 or higher version
> +	 * to get arm boot flags, or we will disable ACPI.
> +	 */
> +	if (table->revision < 5 || fadt->minor_revision < 1) {

				&&

> +		pr_info("FADT version is %d.%d, no PSCI support, should be 5.1 or higher\n",
> +			table->revision, fadt->minor_revision);
> +		disable_acpi();

Instead of disabling ACPI at multiple places in the boot sequence, can't
it be done once if acpi_boot_init failed ?

> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
>   /*
>    * acpi_boot_table_init() called from setup_arch(), always.
>    *	1. find RSDP and get its address, and then find XSDT
> @@ -68,6 +90,21 @@ void __init acpi_boot_table_init(void)
>   	}
>   }
>
> +int __init acpi_boot_init(void)
> +{
> +	int err = 0;
> +
> +	/* If acpi_disabled, bail out */
> +	if (acpi_disabled)
> +		return -ENODEV;
> +
> +	err = acpi_table_parse(ACPI_SIG_FADT, acpi_parse_fadt);
> +	if (err)
> +		pr_err("Can't find FADT\n");
> +
> +	return err;
> +}
> +
>   /*
>    * acpi_suspend_lowlevel() - save kernel state and suspend.
>    *
> diff --git a/arch/arm64/kernel/psci.c b/arch/arm64/kernel/psci.c
> index 9e9798f..2ad2084 100644
> --- a/arch/arm64/kernel/psci.c
> +++ b/arch/arm64/kernel/psci.c
> @@ -15,6 +15,7 @@
>
>   #define pr_fmt(fmt) "psci: " fmt
>
> +#include <linux/acpi.h>
>   #include <linux/init.h>
>   #include <linux/of.h>
>   #include <linux/smp.h>
> @@ -231,6 +232,33 @@ static void psci_sys_poweroff(void)
>   	invoke_psci_fn(PSCI_0_2_FN_SYSTEM_OFF, 0, 0, 0);
>   }
>
> +static void psci_0_2_set_functions(void)
> +{
> +	pr_info("Using standard PSCI v0.2 function IDs\n");
> +	psci_function_id[PSCI_FN_CPU_SUSPEND] = PSCI_0_2_FN64_CPU_SUSPEND;
> +	psci_ops.cpu_suspend = psci_cpu_suspend;
> +
> +	psci_function_id[PSCI_FN_CPU_OFF] = PSCI_0_2_FN_CPU_OFF;
> +	psci_ops.cpu_off = psci_cpu_off;
> +
> +	psci_function_id[PSCI_FN_CPU_ON] = PSCI_0_2_FN64_CPU_ON;
> +	psci_ops.cpu_on = psci_cpu_on;
> +
> +	psci_function_id[PSCI_FN_MIGRATE] = PSCI_0_2_FN64_MIGRATE;
> +	psci_ops.migrate = psci_migrate;
> +
> +	psci_function_id[PSCI_FN_AFFINITY_INFO] = PSCI_0_2_FN64_AFFINITY_INFO;
> +	psci_ops.affinity_info = psci_affinity_info;
> +
> +	psci_function_id[PSCI_FN_MIGRATE_INFO_TYPE] =
> +		PSCI_0_2_FN_MIGRATE_INFO_TYPE;
> +	psci_ops.migrate_info_type = psci_migrate_info_type;
> +
> +	arm_pm_restart = psci_sys_reset;
> +
> +	pm_power_off = psci_sys_poweroff;
> +}
> +

Nit: IMO may be you can move these refactoring as separate patch before
ACPI related changes ?

>   /*
>    * PSCI Function IDs for v0.2+ are well defined so use
>    * standard values.
> @@ -264,29 +292,7 @@ static int psci_0_2_init(struct device_node *np)
>   		}
>   	}
>
> -	pr_info("Using standard PSCI v0.2 function IDs\n");
> -	psci_function_id[PSCI_FN_CPU_SUSPEND] = PSCI_0_2_FN64_CPU_SUSPEND;
> -	psci_ops.cpu_suspend = psci_cpu_suspend;
> -
> -	psci_function_id[PSCI_FN_CPU_OFF] = PSCI_0_2_FN_CPU_OFF;
> -	psci_ops.cpu_off = psci_cpu_off;
> -
> -	psci_function_id[PSCI_FN_CPU_ON] = PSCI_0_2_FN64_CPU_ON;
> -	psci_ops.cpu_on = psci_cpu_on;
> -
> -	psci_function_id[PSCI_FN_MIGRATE] = PSCI_0_2_FN64_MIGRATE;
> -	psci_ops.migrate = psci_migrate;
> -
> -	psci_function_id[PSCI_FN_AFFINITY_INFO] = PSCI_0_2_FN64_AFFINITY_INFO;
> -	psci_ops.affinity_info = psci_affinity_info;
> -
> -	psci_function_id[PSCI_FN_MIGRATE_INFO_TYPE] =
> -		PSCI_0_2_FN_MIGRATE_INFO_TYPE;
> -	psci_ops.migrate_info_type = psci_migrate_info_type;
> -
> -	arm_pm_restart = psci_sys_reset;
> -
> -	pm_power_off = psci_sys_poweroff;
> +	psci_0_2_set_functions();
>
>   out_put_node:
>   	of_node_put(np);
> @@ -333,6 +339,40 @@ out_put_node:
>   	return err;
>   }
>
> +#ifdef CONFIG_ACPI
> +static int get_set_conduit_method_acpi(void)
> +{
> +	pr_info("probing for conduit method from ACPI.\n");
> +
> +	if (acpi_psci_use_hvc())
> +		invoke_psci_fn = __invoke_psci_fn_hvc;
> +	else
> +		invoke_psci_fn = __invoke_psci_fn_smc;
> +
> +	return 0;
> +}
> +
> +/* We use PSCI 0.2+ when ACPI is deployed */
> +static int psci_0_2_init_acpi(void)

May be this can be renamed psci_acpi_init and called from setup directly
instead of calling from DT function with acpi_disabled check.

> +{
> +	if (!acpi_psci_present()) {
> +		pr_info("is not implemented in ACPI.\n");
> +		return -EOPNOTSUPP;
> +	}
> +
> +	get_set_conduit_method_acpi();
> +
> +	psci_0_2_set_functions();
> +
> +	return 0;
> +}
> +#else
> +static inline int psci_0_2_init_acpi(void)
> +{
> +	return -ENODEV;
> +}
> +#endif
> +
>   static const struct of_device_id psci_of_match[] __initconst = {
>   	{ .compatible = "arm,psci",	.data = psci_0_1_init},
>   	{ .compatible = "arm,psci-0.2",	.data = psci_0_2_init},
> @@ -345,6 +385,9 @@ int __init psci_init(void)
>   	const struct of_device_id *matched_np;
>   	psci_initcall_t init_fn;
>
> +	if (!acpi_disabled)
> +		return psci_0_2_init_acpi();
> +

As mentioned above you need not modify this.

>   	np = of_find_matching_node_and_match(NULL, psci_of_match, &matched_np);
>
>   	if (!np)
> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
> index 85c6326..dfc4e4f3 100644
> --- a/arch/arm64/kernel/setup.c
> +++ b/arch/arm64/kernel/setup.c
> @@ -395,6 +395,8 @@ void __init setup_arch(char **cmdline_p)
>   	efi_idmap_init();
>
>   	cpu_logical_map(0) = read_cpuid_mpidr() & MPIDR_HWID_BITMASK;
> +	acpi_boot_init();
> +

Check for the return error here and disable ACPI once rather than at
multiple places all over.

>   	unflatten_device_tree();
>
>   	psci_init();
>