From: Mark Rutland <mark.rutland@arm.com>
To: Elliot Berman <eberman@codeaurora.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Sudeep Holla <sudeep.holla@arm.com>,
Bjorn Andersson <bjorn.andersson@linaro.org>,
Trilok Soni <tsoni@codeaurora.org>,
Prasad Sodagudi <psodagud@codeaurora.org>,
David Collins <collinsd@codeaurora.org>,
linux-arm-kernel@lists.infradead.org,
linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/3] firmware: psci: Add support for dt-supplied SYSTEM_RESET2 type
Date: Wed, 26 Feb 2020 12:10:07 +0000 [thread overview]
Message-ID: <20200226121006.GB21897@lakrids.cambridge.arm.com> (raw)
In-Reply-To: <1582577858-12410-3-git-send-email-eberman@codeaurora.org>
On Mon, Feb 24, 2020 at 12:57:37PM -0800, Elliot Berman wrote:
> Some implementors of PSCI may relax the requirements of the PSCI
> architectural warm reset. In order to comply with PSCI specification, a
> different reset_type value must be used. The alternate PSCI
> SYSTEM_RESET2 may be used in all warm/soft reboot scenarios, replacing
> the architectural warm reset.
As with the binding patch, this sounds like a workaround for a firmware
bug. Can you please elaborate on what exactly your firmware does in this
case?
Thanks,
Mark.
>
> Signed-off-by: Elliot Berman <eberman@codeaurora.org>
> ---
> drivers/firmware/psci/psci.c | 22 ++++++++++++++++++----
> include/uapi/linux/psci.h | 2 ++
> 2 files changed, 20 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
> index 2937d44..8f4609c 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 +507,19 @@ 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-param", ¶m)) {
> + if ((s32)param > 0)
> + pr_warn("%08x is an invalid architectural reset type.\n",
> + param);
> + psci_sys_reset2_reset_param = param;
> + }
> +
> + return 0;
> }
>
> /*
> diff --git a/include/uapi/linux/psci.h b/include/uapi/linux/psci.h
> index 2fcad1d..d786ec8 100644
> --- a/include/uapi/linux/psci.h
> +++ b/include/uapi/linux/psci.h
> @@ -55,6 +55,8 @@
> #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_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
next prev parent reply other threads:[~2020-02-26 12:10 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-24 20:57 [PATCH v2 0/3] ARM PSCI: Add support for vendor-specific SYSTEM_RESET2 Elliot Berman
2020-02-24 20:57 ` [PATCH v2 1/3] dt: psci: Add arm,psci-sys-reset2-type property Elliot Berman
2020-02-25 10:55 ` Sudeep Holla
2020-02-26 12:09 ` Mark Rutland
2020-02-27 0:44 ` Elliot Berman
2020-02-24 20:57 ` [PATCH v2 2/3] firmware: psci: Add support for dt-supplied SYSTEM_RESET2 type Elliot Berman
2020-02-25 11:03 ` Sudeep Holla
2020-02-26 1:37 ` Elliot Berman
2020-02-26 11:59 ` Sudeep Holla
2020-02-26 12:02 ` Sudeep Holla
2020-02-26 12:10 ` Mark Rutland [this message]
2020-02-24 20:57 ` [PATCH v2 3/3] arm64: dts: qcom: sm8250: Add vendor-specific PSCI system reset2 type Elliot Berman
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