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SubjectRe: [PATCH v3 2/3] firmware: psci: Add support for dt-supplied SYSTEM_RESET2 type
On Thu, Mar 05, 2020 at 11:05:28AM -0800, Elliot Berman wrote:
> Some implementors of PSCI may wish to use a different reset type than
> SYSTEM_WARM_RESET. For instance, Qualcomm SoCs support an alternate
> reset_type which may be used in more warm reboot scenarios than
> SYSTEM_WARM_RESET permits (e.g. to reboot into recovery mode).
>
> Signed-off-by: Elliot Berman <eberman@codeaurora.org>

I think we need to discuss the expected semantics on patch 1, and as
things stand, I do not want to take this patch until we understand and
agree to how things should behave.

Thanks,
Mark.

> ---
> drivers/firmware/psci/psci.c | 21 +++++++++++++++++----
> include/uapi/linux/psci.h | 5 +++++
> 2 files changed, 22 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
> index 2937d44..43fe3af 100644
> --- a/drivers/firmware/psci/psci.c
> +++ b/drivers/firmware/psci/psci.c
> @@ -90,6 +90,8 @@ static u32 psci_function_id[PSCI_FN_MAX];
>
> static u32 psci_cpu_suspend_feature;
> static bool psci_system_reset2_supported;
> +static u32 psci_sys_reset2_reset_param =
> + PSCI_1_1_SYSTEM_RESET2_SYSTEM_WARM_RESET;
>
> static inline bool psci_has_ext_power_state(void)
> {
> @@ -272,11 +274,10 @@ static void psci_sys_reset(enum reboot_mode reboot_mode, const char *cmd)
> if ((reboot_mode == REBOOT_WARM || reboot_mode == REBOOT_SOFT) &&
> psci_system_reset2_supported) {
> /*
> - * reset_type[31] = 0 (architectural)
> - * reset_type[30:0] = 0 (SYSTEM_WARM_RESET)
> * cookie = 0 (ignored by the implementation)
> */
> - invoke_psci_fn(PSCI_FN_NATIVE(1_1, SYSTEM_RESET2), 0, 0, 0);
> + invoke_psci_fn(PSCI_FN_NATIVE(1_1, SYSTEM_RESET2),
> + psci_sys_reset2_reset_param, 0, 0);
> } else {
> invoke_psci_fn(PSCI_0_2_FN_SYSTEM_RESET, 0, 0, 0);
> }
> @@ -493,6 +494,7 @@ typedef int (*psci_initcall_t)(const struct device_node *);
> static int __init psci_0_2_init(struct device_node *np)
> {
> int err;
> + u32 param;
>
> err = get_set_conduit_method(np);
> if (err)
> @@ -505,7 +507,18 @@ static int __init psci_0_2_init(struct device_node *np)
> * can be carried out according to the specific version reported
> * by firmware
> */
> - return psci_probe();
> + err = psci_probe();
> + if (err)
> + return err;
> +
> + if (psci_system_reset2_supported &&
> + !of_property_read_u32(np, "arm,psci-sys-reset2-vendor-param", &param)) {
> + psci_sys_reset2_reset_param = param |
> + (PSCI_1_1_SYSTEM_RESET2_OWNER_VENDOR <<
> + PSCI_1_1_SYSTEM_RESET2_OWNER_SHIFT);
> + }
> +
> + return 0;
> }
>
> /*
> diff --git a/include/uapi/linux/psci.h b/include/uapi/linux/psci.h
> index 2fcad1d..0829175 100644
> --- a/include/uapi/linux/psci.h
> +++ b/include/uapi/linux/psci.h
> @@ -55,6 +55,11 @@
> #define PSCI_1_0_FN64_SYSTEM_SUSPEND PSCI_0_2_FN64(14)
> #define PSCI_1_1_FN64_SYSTEM_RESET2 PSCI_0_2_FN64(18)
>
> +#define PSCI_1_1_SYSTEM_RESET2_OWNER_SHIFT 31
> +#define PSCI_1_1_SYSTEM_RESET2_OWNER_ARCH 0
> +#define PSCI_1_1_SYSTEM_RESET2_OWNER_VENDOR 1
> +#define PSCI_1_1_SYSTEM_RESET2_SYSTEM_WARM_RESET 0
> +
> /* PSCI v0.2 power state encoding for CPU_SUSPEND function */
> #define PSCI_0_2_POWER_STATE_ID_MASK 0xffff
> #define PSCI_0_2_POWER_STATE_ID_SHIFT 0
> --
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project

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