Re: [PATCH v4 09/18] ARM64 / ACPI: Parse FADT table to get PSCI flags for PSCI init

[Olof Johansson <olof@lixom.net>]

On Fri, Sep 12, 2014 at 10:00:07PM +0800, Hanjun Guo wrote:
> diff --git a/arch/arm64/include/asm/psci.h b/arch/arm64/include/asm/psci.h
> index e5312ea..2454bc5 100644
> --- a/arch/arm64/include/asm/psci.h
> +++ b/arch/arm64/include/asm/psci.h
> @@ -14,6 +14,7 @@
>  #ifndef __ASM_PSCI_H
>  #define __ASM_PSCI_H
>  
> -int psci_init(void);
> +int psci_dt_init(void);
> +int psci_acpi_init(void);
>  
>  #endif /* __ASM_PSCI_H */
> diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
> index 693da7f..9e1ae37 100644
> --- a/arch/arm64/kernel/acpi.c
> +++ b/arch/arm64/kernel/acpi.c
> @@ -13,6 +13,8 @@
>   *  published by the Free Software Foundation.
>   */
>  
> +#define pr_fmt(fmt) "ACPI: " fmt
> +
>  #include <linux/init.h>
>  #include <linux/acpi.h>
>  #include <linux/cpumask.h>
> @@ -49,10 +51,32 @@ 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 revision,
> +	 * and there is a minor revision of FADT which was introduced
> +	 * by ACPI 5.1, we only deal with ACPI 5.1 or higher revision
> +	 * to get arm boot flags, or we will disable ACPI.
> +	 */
> +	if (table->revision > 5 ||
> +	    (table->revision == 5 && fadt->minor_revision >= 1))
> +		return 0;

The commend and code disagree. The code says 5.1 or newer, while the comment say
_only_ 5.1. One or the other needs to change.

[...]

> diff --git a/arch/arm64/kernel/psci.c b/arch/arm64/kernel/psci.c
> index 5539547..15ba470 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>
> @@ -23,6 +24,7 @@
>  #include <linux/delay.h>
>  #include <uapi/linux/psci.h>
>  
> +#include <asm/acpi.h>
>  #include <asm/compiler.h>
>  #include <asm/cpu_ops.h>
>  #include <asm/errno.h>
> @@ -231,6 +233,33 @@ 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;
> +}
> +
>  /*
>   * PSCI Function IDs for v0.2+ are well defined so use
>   * standard values.
> @@ -264,29 +293,7 @@ static int __init 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);
> @@ -339,7 +346,7 @@ static const struct of_device_id psci_of_match[] __initconst = {
>  	{},
>  };
>  
> -int __init psci_init(void)
> +int __init psci_dt_init(void)
>  {
>  	struct device_node *np;
>  	const struct of_device_id *matched_np;
> @@ -354,6 +361,29 @@ int __init psci_init(void)
>  	return init_fn(np);
>  }
>  
> +/*
> + * We use PSCI 0.2+ when ACPI is deployed on ARM64 and it's
> + * explicitly clarified in SBBR
> + */
> +int __init psci_acpi_init(void)
> +{
> +	if (!acpi_psci_present()) {
> +		pr_info("is not implemented in ACPI.\n");
> +		return -EOPNOTSUPP;
> +	}
> +
> +	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;
> +
> +	psci_0_2_set_functions();
> +
> +	return 0;
> +}
> +
>  #ifdef CONFIG_SMP
>  
>  static int __init cpu_psci_cpu_init(struct device_node *dn, unsigned int cpu)
> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
> index 5796734..7ba20d4 100644
> --- a/arch/arm64/kernel/setup.c
> +++ b/arch/arm64/kernel/setup.c
> @@ -398,10 +398,12 @@ void __init setup_arch(char **cmdline_p)
>  	efi_idmap_init();
>  
>  	cpu_logical_map(0) = read_cpuid_mpidr() & MPIDR_HWID_BITMASK;
> -	if (acpi_disabled)
> +	if (acpi_disabled) {
>  		unflatten_device_tree();
> -
> -	psci_init();
> +		psci_dt_init();
> +	} else {
> +		psci_acpi_init();
> +	}

This is slightly nitty now, but I think it'd be slightly easier to follow
boot path if the switch for acpi disabled/enabled was in psci.c. It'd also allow
psci_dt_init() and psci_acpi_init() to be static.

I.e. keep a psci_init() and just make it call one or the other.


-Olof