Re: [PATCH 4/5] firmware: xilinx: Add sysfs to set shutdown scope

Michal Simek
2019-12-18T14:26:19Z

On 05. 12. 19 0:29, Jolly Shah wrote:
> From: Rajan Vaja <rajan.vaja@xilinx.com>
>
> The Linux shutdown functionality implemented via PSCI system_off does
> not include an option to set a scope, i.e. which parts of the system to
> shut down.
>
> This patch creates sysfs that allows to set the shutdown scope for the
> next shutdown request. When the next shutdown is performed, the platform
> specific portion of PSCI-system_off can use the chosen shutdown scope.
>
> Signed-off-by: Stefan Krsmanovic <stefan.krsmanovic@aggios.com>
> Signed-off-by: Michal Simek <michal.simek@xilinx.com>
> Signed-off-by: Rajan Vaja <rajan.vaja@xilinx.com>
> Signed-off-by: Jolly Shah <jolly.shah@xilinx.com>
> ---
> Documentation/ABI/stable/sysfs-firmware-zynqmp | 32 ++++++
> drivers/firmware/xilinx/zynqmp.c | 141 +++++++++++++++++++++++++
> include/linux/firmware/xlnx-zynqmp.h | 12 +++
> 3 files changed, 185 insertions(+)
>
> diff --git a/Documentation/ABI/stable/sysfs-firmware-zynqmp b/Documentation/ABI/stable/sysfs-firmware-zynqmp
> index 0a75812..13e4fd2 100644
> --- a/Documentation/ABI/stable/sysfs-firmware-zynqmp
> +++ b/Documentation/ABI/stable/sysfs-firmware-zynqmp
> @@ -48,3 +48,35 @@ Description:
> # echo 0xFFFFFFFF 0x1234ABCD > /sys/firmware/zynqmp/pggs0
>
> Users: Xilinx
> +
> +What: /sys/firmware/zynqmp/shutdown_scope
> +Date: February 2018
> +KernelVersion: 4.15.6

ditto.

> +Contact: "Jolly Shah" <jollys@xilinx.com>
> +Description:
> + This sysfs interface allows to set the shutdown scope for the
> + next shutdown request. When the next shutdown is performed, the
> + platform specific portion of PSCI-system_off can use the chosen
> + shutdown scope.
> +
> + Following are available shutdown scopes(subtypes):
> +
> + subsystem: Only the APU along with all of its peripherals
> + not used by other processing units will be
> + shut down. This may result in the FPD power
> + domain being shut down provided that no other
> + processing unit uses FPD peripherals or DRAM.
> + ps_only: The complete PS will be shut down, including the
> + RPU, PMU, etc. Only the PL domain (FPGA)
> + remains untouched.
> + system: The complete system/device is shut down.
> +
> + Usage:
> + # cat /sys/firmware/zynqmp/shutdown_scope
> + # echo <scope> > /sys/firmware/zynqmp/shutdown_scope
> +
> + Example:
> + # cat /sys/firmware/zynqmp/shutdown_scope
> + # echo "subsystem" > /sys/firmware/zynqmp/shutdown_scope
> +
> +Users: Xilinx
> diff --git a/drivers/firmware/xilinx/zynqmp.c b/drivers/firmware/xilinx/zynqmp.c
> index 8dcf5a4..b23bda4 100644
> --- a/drivers/firmware/xilinx/zynqmp.c
> +++ b/drivers/firmware/xilinx/zynqmp.c
> @@ -746,6 +746,146 @@ const struct zynqmp_eemi_ops *zynqmp_pm_get_eemi_ops(void)
> EXPORT_SYMBOL_GPL(zynqmp_pm_get_eemi_ops);
>
> /**
> + * struct zynqmp_pm_shutdown_scope - Struct for shutdown scope
> + * @subtype: Shutdown subtype
> + * @name: Matching string for scope argument
> + *
> + * This struct encapsulates mapping between shutdown scope ID and string.
> + */
> +struct zynqmp_pm_shutdown_scope {
> + const enum zynqmp_pm_shutdown_subtype subtype;
> + const char *name;
> +};
> +
> +static struct zynqmp_pm_shutdown_scope shutdown_scopes[] = {
> + [ZYNQMP_PM_SHUTDOWN_SUBTYPE_SUBSYSTEM] = {
> + .subtype = ZYNQMP_PM_SHUTDOWN_SUBTYPE_SUBSYSTEM,
> + .name = "subsystem",
> + },
> + [ZYNQMP_PM_SHUTDOWN_SUBTYPE_PS_ONLY] = {
> + .subtype = ZYNQMP_PM_SHUTDOWN_SUBTYPE_PS_ONLY,
> + .name = "ps_only",
> + },
> + [ZYNQMP_PM_SHUTDOWN_SUBTYPE_SYSTEM] = {
> + .subtype = ZYNQMP_PM_SHUTDOWN_SUBTYPE_SYSTEM,
> + .name = "system",
> + },
> +};
> +
> +static struct zynqmp_pm_shutdown_scope *selected_scope =
> + &shutdown_scopes[ZYNQMP_PM_SHUTDOWN_SUBTYPE_SYSTEM];
> +
> +/**
> + * zynqmp_pm_is_shutdown_scope_valid - Check if shutdown scope string is valid
> + * @scope_string: Shutdown scope string
> + *
> + * Return: Return pointer to matching shutdown scope struct from
> + * array of available options in system if string is valid,
> + * otherwise returns NULL.
> + */
> +static struct zynqmp_pm_shutdown_scope*
> + zynqmp_pm_is_shutdown_scope_valid(const char *scope_string)
> +{
> + int count;
> +
> + for (count = 0; count < ARRAY_SIZE(shutdown_scopes); count++)
> + if (sysfs_streq(scope_string, shutdown_scopes[count].name))
> + return &shutdown_scopes[count];
> +
> + return NULL;
> +}
> +
> +/**
> + * shutdown_scope_show - Show shutdown_scope sysfs attribute
> + * @kobj: Kobject structure
> + * @attr: Kobject attribute structure
> + * @buf: Requested available shutdown_scope attributes string
> + *
> + * User-space interface for viewing the available scope options for system
> + * shutdown. Scope option for next shutdown call is marked with [].
> + *
> + * Usage: cat /sys/firmware/zynqmp/shutdown_scope
> + *
> + * Return: Number of bytes printed into the buffer.
> + */
> +static ssize_t shutdown_scope_show(struct kobject *kobj,
> + struct kobj_attribute *attr,
> + char *buf)
> +{
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(shutdown_scopes); i++) {
> + if (&shutdown_scopes[i] == selected_scope) {
> + strcat(buf, "[");
> + strcat(buf, shutdown_scopes[i].name);
> + strcat(buf, "]");
> + } else {
> + strcat(buf, shutdown_scopes[i].name);
> + }
> + strcat(buf, " ");
> + }
> + strcat(buf, "\n");
> +
> + return strlen(buf);
> +}
> +
> +/**
> + * shutdown_scope_store - Store shutdown_scope sysfs attribute
> + * @kobj: Kobject structure
> + * @attr: Kobject attribute structure
> + * @buf: User entered shutdown_scope attribute string
> + * @count: Buffer size
> + *
> + * User-space interface for setting the scope for the next system shutdown.
> + * Usage: echo <scope> > /sys/firmware/zynqmp/shutdown_scope
> + *
> + * The Linux shutdown functionality implemented via PSCI system_off does not
> + * include an option to set a scope, i.e. which parts of the system to shut
> + * down.
> + *
> + * This API function allows to set the shutdown scope for the next shutdown
> + * request by passing it to the ATF running in EL3. When the next shutdown
> + * is performed, the platform specific portion of PSCI-system_off can use
> + * the chosen shutdown scope.
> + *
> + * subsystem: Only the APU along with all of its peripherals not used by other
> + * processing units will be shut down. This may result in the FPD
> + * power domain being shut down provided that no other processing
> + * unit uses FPD peripherals or DRAM.
> + * ps_only: The complete PS will be shut down, including the RPU, PMU, etc.
> + * Only the PL domain (FPGA) remains untouched.
> + * system: The complete system/device is shut down.
> + *
> + * Return: count argument if request succeeds, the corresponding error
> + * code otherwise
> + */
> +static ssize_t shutdown_scope_store(struct kobject *kobj,
> + struct kobj_attribute *attr,
> + const char *buf, size_t count)
> +{
> + int ret;
> + struct zynqmp_pm_shutdown_scope *scope;
> +
> + scope = zynqmp_pm_is_shutdown_scope_valid(buf);
> + if (!scope)
> + return -EINVAL;
> +
> + ret = zynqmp_pm_system_shutdown(ZYNQMP_PM_SHUTDOWN_TYPE_SETSCOPE_ONLY,
> + scope->subtype);
> + if (ret) {
> + pr_err("unable to set shutdown scope %s\n", buf);
> + return ret;
> + }
> +
> + selected_scope = scope;
> +
> + return count;
> +}
> +
> +static struct kobj_attribute zynqmp_attr_shutdown_scope =
> + __ATTR_RW(shutdown_scope);

the same as was in 1/5.

> +
> +/**
> * config_reg_store - Write config_reg sysfs attribute
> * @kobj: Kobject structure
> * @attr: Kobject attribute structure
> @@ -870,6 +1010,7 @@ static struct kobj_attribute zynqmp_attr_config_reg =
> __ATTR_RW(config_reg);
>
> static struct attribute *attrs[] = {
> + &zynqmp_attr_shutdown_scope.attr,
> &zynqmp_attr_config_reg.attr,
> NULL,
> };
> diff --git a/include/linux/firmware/xlnx-zynqmp.h b/include/linux/firmware/xlnx-zynqmp.h
> index b96ea5d..54061de 100644
> --- a/include/linux/firmware/xlnx-zynqmp.h
> +++ b/include/linux/firmware/xlnx-zynqmp.h
> @@ -277,6 +277,18 @@ enum pm_register_access_id {
> CONFIG_REG_READ,
> };
>
> +enum zynqmp_pm_shutdown_type {
> + ZYNQMP_PM_SHUTDOWN_TYPE_SHUTDOWN,
> + ZYNQMP_PM_SHUTDOWN_TYPE_RESET,
> + ZYNQMP_PM_SHUTDOWN_TYPE_SETSCOPE_ONLY,
> +};
> +
> +enum zynqmp_pm_shutdown_subtype {
> + ZYNQMP_PM_SHUTDOWN_SUBTYPE_SUBSYSTEM,
> + ZYNQMP_PM_SHUTDOWN_SUBTYPE_PS_ONLY,
> + ZYNQMP_PM_SHUTDOWN_SUBTYPE_SYSTEM,
> +};
> +
> /**
> * struct zynqmp_pm_query_data - PM query data
> * @qid: query ID
>

M