[PATCH 11/14] drivers: firmware: psci: Allow OS Initiated suspend mode

[Vikas Sajjan]

Hi Lina,

On Thu, Jun 23, 2016 at 1:06 AM, Lina Iyer <lina.iyer at linaro.org> wrote:
> PSCI firmware v1.0 onwards may support 2 different modes for
> CPU_SUSPEND. Platform coordinated mode is the default and every firmware
> should support it. OS Initiated mode is optional for the firmware to
> implement and allow Linux to make an better decision on the state of
> the CPU cluster heirarchy.
>
> With the kernel capable of deciding the state for CPU cluster and
> coherency domains, the OS Initiated mode may now be used by the kernel,
> provided the firmware supports it. SET_SUSPEND_MODE is a PSCI function
> available on v1.0 onwards and can be used to set the mode in the
> firmware.
>
> Cc: Lorenzo Pieralisi <lorenzo.pieralisi at arm.com>
> Cc: Mark Rutland <mark.rutland at arm.com>
> Signed-off-by: Lina Iyer <lina.iyer at linaro.org>
> [Ulf: Rebased on 4.7 rc1]
> Signed-off-by: Ulf Hansson <ulf.hansson at linaro.org>
> ---
>  drivers/firmware/psci.c   | 22 +++++++++++++++++++++-
>  include/uapi/linux/psci.h |  5 +++++
>  2 files changed, 26 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c
> index 03e0458..3920aba 100644
> --- a/drivers/firmware/psci.c
> +++ b/drivers/firmware/psci.c
> @@ -52,6 +52,7 @@
>   * require cooperation with a Trusted OS driver.
>   */
>  static int resident_cpu = -1;
> +static bool psci_has_osi_pd;
>
>  bool psci_tos_resident_on(int cpu)
>  {
> @@ -563,10 +564,29 @@ out_put_node:
>         return err;
>  }
>
> +static int __init psci_1_0_init(struct device_node *np)
> +{
> +       int ret;
> +
> +       ret = psci_0_2_init(np);
> +       if (ret)
> +               return ret;
> +
> +       /* Check if PSCI OSI mode is available */
> +       ret = psci_features(psci_function_id[PSCI_FN_CPU_SUSPEND]);
> +       if (ret & PSCI_1_0_OS_INITIATED) {
> +               ret = psci_features(PSCI_1_0_FN_SET_SUSPEND_MODE);
> +               if (!ret)
> +                       psci_has_osi_pd = true;

IMHO, its better to have this done in psci_init_cpu_suspend() itself
for 2 reasons

a] psci_init_cpu_suspend() already calls
psci_features(psci_function_id[PSCI_FN_CPU_SUSPEND])
b] by moving this in psci_init_cpu_suspend() we make this support
available even for ACPI platforms, since psci_acpi_init() calls
psci_probe() and this calls  psci_init_cpu_suspend() for
PSCI_VERSION_MAJOR(ver) >= 1

I even posted a patch [1] yesterday, without being aware of your
patchset for the same.

[1] http://www.spinics.net/lists/arm-kernel/msg513682.html


> +       }
> +
> +       return 0;
> +}
> +
>  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},
> -       { .compatible = "arm,psci-1.0", .data = psci_0_2_init},
> +       { .compatible = "arm,psci-1.0", .data = psci_1_0_init},
>         {},
>  };
>
> diff --git a/include/uapi/linux/psci.h b/include/uapi/linux/psci.h
> index 3d7a0fc..7dd778e 100644
> --- a/include/uapi/linux/psci.h
> +++ b/include/uapi/linux/psci.h
> @@ -48,6 +48,7 @@
>
>  #define PSCI_1_0_FN_PSCI_FEATURES              PSCI_0_2_FN(10)
>  #define PSCI_1_0_FN_SYSTEM_SUSPEND             PSCI_0_2_FN(14)
> +#define PSCI_1_0_FN_SET_SUSPEND_MODE           PSCI_0_2_FN(15)
>
>  #define PSCI_1_0_FN64_SYSTEM_SUSPEND           PSCI_0_2_FN64(14)
>
> @@ -93,6 +94,10 @@
>  #define PSCI_1_0_FEATURES_CPU_SUSPEND_PF_MASK  \
>                         (0x1 << PSCI_1_0_FEATURES_CPU_SUSPEND_PF_SHIFT)
>
> +#define PSCI_1_0_OS_INITIATED                  BIT(0)
> +#define PSCI_1_0_SUSPEND_MODE_PC               0
> +#define PSCI_1_0_SUSPEND_MODE_OSI              1
> +
>  /* PSCI return values (inclusive of all PSCI versions) */
>  #define PSCI_RET_SUCCESS                       0
>  #define PSCI_RET_NOT_SUPPORTED                 -1
> --
> 2.7.4
>
>
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