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SubjectRe: [PATCH 06/19] ARM64 / ACPI: Parse FADT table to get PSCI flags for PSCI init
Date
On Thu, 24 Jul 2014 21:00:12 +0800, Hanjun Guo <hanjun.guo@linaro.org> 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 | 2 +
> arch/arm64/kernel/acpi.c | 50 ++++++++++++++++++++++
> arch/arm64/kernel/psci.c | 95 +++++++++++++++++++++++++++++------------
> arch/arm64/kernel/setup.c | 2 +
> 4 files changed, 121 insertions(+), 28 deletions(-)
>
> diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
> index 44b617f..67dac90 100644
> --- a/arch/arm64/include/asm/acpi.h
> +++ b/arch/arm64/include/asm/acpi.h
> @@ -18,6 +18,8 @@ extern int acpi_disabled;
> extern int acpi_noirq;
> extern int acpi_pci_disabled;
> extern int acpi_strict;
> +extern int acpi_psci_present;
> +extern int acpi_psci_use_hvc;
>
> static inline void disable_acpi(void)
> {
> diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
> index f5a10b5..374926f 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>
> @@ -34,6 +36,12 @@ EXPORT_SYMBOL(acpi_disabled);
> int acpi_pci_disabled; /* skip ACPI PCI scan and IRQ initialization */
> EXPORT_SYMBOL(acpi_pci_disabled);
>
> +/* 1 to indicate PSCI is implemented */
> +int acpi_psci_present;
> +
> +/* 1 to indicate HVC must be used instead of SMC as the PSCI conduit */
> +int acpi_psci_use_hvc;
> +
> /*
> * __acpi_map_table() will be called before page_init(), so early_ioremap()
> * or early_memremap() should be called here to for ACPI table mapping.
> @@ -54,6 +62,33 @@ void __init __acpi_unmap_table(char *map, unsigned long size)
> early_iounmap(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_version < 1) {
> + pr_info("FADT version is %d.%d, no PSCI support, should be 5.1 or higher\n",
> + table->revision, fadt->minor_version);
> + acpi_psci_present = 0;
> + disable_acpi();
> + return -EINVAL;
> + }
> +
> + if (acpi_gbl_FADT.arm_boot_flags & ACPI_FADT_PSCI_COMPLIANT)
> + acpi_psci_present = 1;
> +
> + if (acpi_gbl_FADT.arm_boot_flags & ACPI_FADT_PSCI_USE_HVC)
> + acpi_psci_use_hvc = 1;
> +
> + return 0;
> +}
> +
> /*
> * acpi_boot_table_init() called from setup_arch(), always.
> * 1. find RSDP and get its address, and then find XSDT
> @@ -75,6 +110,21 @@ 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;
> +}
> +
> static int __init parse_acpi(char *arg)
> {
> if (!arg)
> diff --git a/arch/arm64/kernel/psci.c b/arch/arm64/kernel/psci.c
> index 9e9798f..adb25f3 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;
> +}
> +
> /*
> * 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 +339,33 @@ out_put_node:
> return err;
> }
>
> +#ifdef CONFIG_ACPI
> +static int get_set_conduit_method_acpi(void)
> +{
> + 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)
> +{
> + 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},
> @@ -345,13 +378,19 @@ int __init psci_init(void)
> const struct of_device_id *matched_np;
> psci_initcall_t init_fn;
>
> - np = of_find_matching_node_and_match(NULL, psci_of_match, &matched_np);
> + if (acpi_disabled) {
> + np = of_find_matching_node_and_match(NULL,
> + psci_of_match, &matched_np);
>
> - if (!np)
> - return -ENODEV;
> + if (!np)
> + return -ENODEV;
> +
> + init_fn = (psci_initcall_t)matched_np->data;
> +
> + return init_fn(np);
> + }
>
> - init_fn = (psci_initcall_t)matched_np->data;
> - return init_fn(np);
> + return psci_0_2_init_acpi();
> }

So, while the functionality is sound, this is kind of a stinky diff. The
ACPI path should not push the OF code into a sub branch. Make it look
like this instead (with the advantage that the diff will be simpler):

+ if (IS_ENABLED(CONFIG_ACPI) && !acpi_disabled)
+ return psci_0_2_init_acpi();

np = of_find_matching_node_and_match(NULL, psci_of_match, &matched_np);

if (!np)
return -ENODEV;

init_fn = (psci_initcall_t)matched_np->data;
return init_fn(np);

g.


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