linux-kernel - Re: [PATCH v3 24/24] firmware: xilinx: Add sysfs and API to set boot health status

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Date:   Wed, 18 Mar 2020 12:53:58 +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>,
        Jolly Shah <jollys@...inx.com>,
        Tejas Patel <tejas.patel@...inx.com>
Subject: Re: [PATCH v3 24/24] firmware: xilinx: Add sysfs and API to set boot
 health status

On Fri, Mar 06, 2020 at 03:47:32PM -0800, Jolly Shah wrote:
> From: Rajan Vaja <rajan.vaja@...inx.com>
> 
> Add sysfs interface to set boot health status from user space.
> Add API used by this interface to communicate with firmware.
> 
> If PMUFW is compiled with CHECK_HEALTHY_BOOT, it will check the
> healthy bit on FPD WDT expiration. If healthy bit is set by a user
> application running in Linux, PMUFW will do APU only restart. If
> healthy bit is not set during FPD WDT expiration, PMUFW will do
> system restart.
> 
> Signed-off-by: Rajan Vaja <rajan.vaja@...inx.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        | 21 ++++++++
>  drivers/firmware/xilinx/zynqmp.c                   | 63 ++++++++++++++++++++++
>  include/linux/firmware/xlnx-zynqmp.h               |  3 ++
>  3 files changed, 87 insertions(+)
> 
> diff --git a/Documentation/ABI/stable/sysfs-driver-firmware-zynqmp b/Documentation/ABI/stable/sysfs-driver-firmware-zynqmp
> index b46ec0c..a37b408 100644
> --- a/Documentation/ABI/stable/sysfs-driver-firmware-zynqmp
> +++ b/Documentation/ABI/stable/sysfs-driver-firmware-zynqmp
> @@ -80,3 +80,24 @@ Description:
>  		# echo "subsystem" > /sys/devices/platform/firmware\:zynqmp-firmware/shutdown_scope
>  
>  Users:		Xilinx
> +
> +What:		/sys/devices/platform/firmware\:zynqmp-firmware/health_status
> +Date:		March 2020
> +KernelVersion:	5.6
> +Contact:	"Jolly Shah" <jollys@...inx.com>
> +Description:
> +		This sysfs interface allows to set the health status. If PMUFW
> +		is compiled with CHECK_HEALTHY_BOOT, it will check the healthy
> +		bit on FPD WDT expiration. If healthy bit is set by a user
> +		application running in Linux, PMUFW will do APU only restart. If
> +		healthy bit is not set during FPD WDT expiration, PMUFW will do
> +		system restart.
> +
> +		Usage:
> +		Set healthy bit
> +		# echo 1 > /sys/devices/platform/firmware\:zynqmp-firmware/health_status
> +
> +		Unset healthy bit
> +		# echo 0 > /sys/devices/platform/firmware\:zynqmp-firmware/health_status
> +
> +Users:		Xilinx
> diff --git a/drivers/firmware/xilinx/zynqmp.c b/drivers/firmware/xilinx/zynqmp.c
> index 9caf1cf..fc3aa4e 100644
> --- a/drivers/firmware/xilinx/zynqmp.c
> +++ b/drivers/firmware/xilinx/zynqmp.c
> @@ -667,6 +667,21 @@ int zynqmp_pm_read_pggs(u32 index, u32 *value)
>  EXPORT_SYMBOL_GPL(zynqmp_pm_read_pggs);
>  
>  /**
> + * zynqmp_pm_set_boot_health_status() - PM API for setting healthy boot status
> + * @value	Status value to be written
> + *
> + * This function sets healthy bit value to indicate boot health status
> + * to firmware.
> + *
> + * @return      Returns status, either success or error+reason
> + */
> +int zynqmp_pm_set_boot_health_status(u32 value)
> +{
> +	return zynqmp_pm_invoke_fn(PM_IOCTL, 0, IOCTL_SET_BOOT_HEALTH_STATUS,
> +				   value, 0, NULL);
> +}
> +
> +/**
>   * zynqmp_pm_reset_assert - Request setting of reset (1 - assert, 0 - release)
>   * @reset:		Reset to be configured
>   * @assert_flag:	Flag stating should reset be asserted (1) or
> @@ -995,6 +1010,53 @@ static const struct attribute_group shutdown_scope_attribute_group = {
>  };
>  
>  /**
> + * health_status_store - Store health_status sysfs attribute
> + * @device:	Device structure
> + * @attr:	Device attribute structure
> + * @buf:	User entered health_status attribute string
> + * @count:	Buffer size
> + *
> + * User-space interface for setting the boot health status.
> + * Usage: echo <value> > /sys/devices/platform/firmware\:zynqmp-firmware/health_status
> + *
> + * Value:
> + *	1 - Set healthy bit to 1
> + *	0 - Unset healthy bit
> + *
> + * Return:	count argument if request succeeds, the corresponding error
> + *		code otherwise
> + */
> +static ssize_t health_status_store(struct device *device,
> +				   struct device_attribute *attr,
> +				   const char *buf, size_t count)
> +{
> +	int ret;
> +	unsigned int value;
> +
> +	ret = kstrtouint(buf, 10, &value);
> +	if (ret)
> +		return ret;
> +
> +	ret = zynqmp_pm_set_boot_health_status(value);
> +	if (ret) {
> +		pr_err("unable to set healthy bit value to %u\n", value);

You have a valid struct device right there, use it!

dev_err() please...

thanks,

greg k-h