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Date: Wed, 18 Mar 2020 12:53:17 +0100
From: Greg KH <gregkh@...uxfoundation.org>
To: Jolly Shah <jolly.shah@...inx.com>
Cc: ard.biesheuvel@...aro.org, mingo@...nel.org,
matt@...eblueprint.co.uk, sudeep.holla@....com,
hkallweit1@...il.com, keescook@...omium.org,
dmitry.torokhov@...il.com, michal.simek@...inx.com,
rajanv@...inx.com, linux-arm-kernel@...ts.infradead.org,
linux-kernel@...r.kernel.org, Rajan Vaja <rajan.vaja@...inx.com>,
Stefan Krsmanovic <stefan.krsmanovic@...ios.com>,
Jolly Shah <jollys@...inx.com>,
Tejas Patel <tejas.patel@...inx.com>
Subject: Re: [PATCH v3 23/24] firmware: xilinx: Add sysfs to set shutdown
scope
On Fri, Mar 06, 2020 at 03:47:31PM -0800, Jolly Shah wrote:
> From: Rajan Vaja <rajan.vaja@...inx.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: Rajan Vaja <rajan.vaja@...inx.com>
> Signed-off-by: Stefan Krsmanovic <stefan.krsmanovic@...ios.com>
> Signed-off-by: Michal Simek <michal.simek@...inx.com>
> Signed-off-by: Jolly Shah <jollys@...inx.com>
> Signed-off-by: Tejas Patel <tejas.patel@...inx.com>
> Signed-off-by: Jolly Shah <jolly.shah@...inx.com>
> ---
> .../ABI/stable/sysfs-driver-firmware-zynqmp | 32 +++++
> drivers/firmware/xilinx/zynqmp.c | 150 ++++++++++++++++++++-
> include/linux/firmware/xlnx-zynqmp.h | 12 ++
> 3 files changed, 193 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/ABI/stable/sysfs-driver-firmware-zynqmp b/Documentation/ABI/stable/sysfs-driver-firmware-zynqmp
> index 7fd6e70..b46ec0c 100644
> --- a/Documentation/ABI/stable/sysfs-driver-firmware-zynqmp
> +++ b/Documentation/ABI/stable/sysfs-driver-firmware-zynqmp
> @@ -48,3 +48,35 @@ Description:
> # echo 0xFFFFFFFF 0x1234ABCD > /sys/devices/platform/firmware\:zynqmp-firmware/pggs0
>
> Users: Xilinx
> +
> +What: /sys/devices/platform/firmware\:zynqmp-firmware/shutdown_scope
> +Date: March 2020
> +KernelVersion: 5.6
> +Contact: "Jolly Shah" <jollys@...inx.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/devices/platform/firmware\:zynqmp-firmware/shutdown_scope
> + # echo <scope> > /sys/devices/platform/firmware\:zynqmp-firmware/shutdown_scope
> +
> + Example:
> + # cat /sys/devices/platform/firmware\:zynqmp-firmware/shutdown_scope
> + # echo "subsystem" > /sys/devices/platform/firmware\:zynqmp-firmware/shutdown_scope
> +
> +Users: Xilinx
> diff --git a/drivers/firmware/xilinx/zynqmp.c b/drivers/firmware/xilinx/zynqmp.c
> index d3f637b..9caf1cf 100644
> --- a/drivers/firmware/xilinx/zynqmp.c
> +++ b/drivers/firmware/xilinx/zynqmp.c
> @@ -847,6 +847,154 @@ int zynqmp_pm_system_shutdown(const u32 type, const u32 subtype)
> }
>
> /**
> + * 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
> + * @device: Device structure
> + * @attr: Device 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/devices/platform/firmware\:zynqmp-firmware/shutdown_scope
> + *
> + * Return: Number of bytes printed into the buffer.
> + */
> +static ssize_t shutdown_scope_show(struct device *device,
> + struct device_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
> + * @device: Device structure
> + * @attr: Device 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/devices/platform/firmware\:zynqmp-firmware/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 device *device,
> + struct device_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 DEVICE_ATTR_RW(shutdown_scope);
> +
> +static struct attribute *zynqmp_shutdown_scope_attrs[] = {
> + &dev_attr_shutdown_scope.attr,
> + NULL,
> +};
> +
> +static const struct attribute_group shutdown_scope_attribute_group = {
> + .attrs = zynqmp_shutdown_scope_attrs,
> +};
ATTRIBUTE_GROUPS()?
thanks,
greg k-h
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