Subject: [PATCH v8 11/21] ARM64 / ACPI: Get PSCI flags in FADT for PSCI init

From: [email-masked] (Lorenzo Pieralisi)
Date: Wed, 4 Feb 2015 16:43:28 +0000

On Mon, Feb 02, 2015 at 12:45:39PM +0000, Hanjun Guo wrote:
> From: Graeme Gregory <[email-masked]>
> 
> There are two flags: PSCI_COMPLIANT and PSCI_USE_HVC. When set,
> the former signals to the OS that the firmware 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 in ACPI 5.1, FADT table was
> parsed in ACPI table init and copy to struct acpi_gbl_FADT, so
> use the flags in struct acpi_gbl_FADT for PSCI init.

So you do rely on a global FADT being available, if you use it for PSCI
detection you can use it for ACPI revision detection too, right ?

Point is, either we should not use the global FADT table, or we use
it consistently, or there is something I am unaware of that prevents
you from using in some code paths and I would like to understand
why.

Thanks,
Lorenzo

> 
> Since ACPI 5.1 doesn't support self defined PSCI function IDs,
> which means that only PSCI 0.2+ is supported in ACPI.
> 
> CC: Lorenzo Pieralisi <[email-masked]>
> CC: Catalin Marinas <[email-masked]>
> CC: Will Deacon <[email-masked]>
> Tested-by: Suravee Suthikulpanit <[email-masked]>
> Tested-by: Yijing Wang <[email-masked]>
> Tested-by: Mark Langsdorf <[email-masked]>
> Tested-by: Jon Masters <[email-masked]>
> Tested-by: Timur Tabi <[email-masked]>
> Signed-off-by: Graeme Gregory <[email-masked]>
> Signed-off-by: Tomasz Nowicki <[email-masked]>
> Signed-off-by: Hanjun Guo <[email-masked]>
> ---
>  arch/arm64/include/asm/acpi.h | 14 ++++++++
>  arch/arm64/include/asm/psci.h |  3 +-
>  arch/arm64/kernel/psci.c      | 78 ++++++++++++++++++++++++++++++-------------
>  arch/arm64/kernel/setup.c     |  8 +++--
>  4 files changed, 75 insertions(+), 28 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
> index 9fcf632..1aea87c 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;
> @@ -50,6 +62,8 @@ static inline void arch_fix_phys_package_id(int num, u32 slot) { }
>  #else
>  static inline void disable_acpi(void) { }
>  static inline void enable_acpi(void) { }
> +static inline bool acpi_psci_present(void) { return false; }
> +static inline bool acpi_psci_use_hvc(void) { return false; }
>  #endif /* CONFIG_ACPI */
>  
>  #endif /*_ASM_ACPI_H*/
> 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/psci.c b/arch/arm64/kernel/psci.c
> index f1dbca7..0ec0dc5 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>
> @@ -24,6 +25,7 @@
>  #include <linux/slab.h>
>  #include <uapi/linux/psci.h>
>  
> +#include <asm/acpi.h>
>  #include <asm/compiler.h>
>  #include <asm/cpu_ops.h>
>  #include <asm/errno.h>
> @@ -304,6 +306,33 @@ static void psci_sys_poweroff(void)
>  	invoke_psci_fn(PSCI_0_2_FN_SYSTEM_OFF, 0, 0, 0);
>  }
>  
> +static void __init 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.
> @@ -337,29 +366,7 @@ 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);
> @@ -412,7 +419,7 @@ 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;
> @@ -427,6 +434,29 @@ 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 553967d..43ae914 100644
> --- a/arch/arm64/kernel/setup.c
> +++ b/arch/arm64/kernel/setup.c
> @@ -446,10 +446,12 @@ void __init setup_arch(char **cmdline_p)
>  	efi_idmap_init();
>  	early_ioremap_reset();
>  
> -	if (acpi_disabled)
> +	if (acpi_disabled) {
>  		unflatten_device_tree();
> -
> -	psci_init();
> +		psci_dt_init();
> +	} else {
> +		psci_acpi_init();
> +	}
>  
>  	cpu_read_bootcpu_ops();
>  #ifdef CONFIG_SMP
> -- 
> 1.9.1
> 
>