firmware: xilinx: Add sysfs and API to set boot health status

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 <[e-mail]>
Signed-off-by: Michal Simek <[e-mail]>
Signed-off-by: Tejas Patel <[e-mail]>
Signed-off-by: Jolly Shah <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

Documentation/ABI/stable/sysfs-driver-firmware-zynqmp

···
 		# 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" <[e-mail]>
+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

drivers/firmware/xilinx/zynqmp.c

···
 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
···
 
 static DEVICE_ATTR_RW(shutdown_scope);
 
+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) {
+		dev_err(device, "unable to set healthy bit value to %u\n",
+			value);
+		return ret;
+	}
+
+	return count;
+}
+
+static DEVICE_ATTR_WO(health_status);
+
 static ssize_t ggs_show(struct device *device,
 			struct device_attribute *attr,
 			char *buf,
···
 	&dev_attr_pggs2.attr,
 	&dev_attr_pggs3.attr,
 	&dev_attr_shutdown_scope.attr,
+	&dev_attr_health_status.attr,
 	NULL,
 };
 

include/linux/firmware/xlnx-zynqmp.h

···
 	IOCTL_READ_GGS = 13,
 	IOCTL_WRITE_PGGS = 14,
 	IOCTL_READ_PGGS = 15,
+	/* Set healthy bit value */
+	IOCTL_SET_BOOT_HEALTH_STATUS = 17,
 };
 
 enum pm_query_id {
···
 int zynqmp_pm_write_pggs(u32 index, u32 value);
 int zynqmp_pm_read_pggs(u32 index, u32 *value);
 int zynqmp_pm_system_shutdown(const u32 type, const u32 subtype);
+int zynqmp_pm_set_boot_health_status(u32 value);
 #else
 static inline struct zynqmp_eemi_ops *zynqmp_pm_get_eemi_ops(void)
 {
···
 	return -ENODEV;
 }
 static inline int zynqmp_pm_system_shutdown(const u32 type, const u32 subtype)
+{
+	return -ENODEV;
+}
+static inline int zynqmp_pm_set_boot_health_status(u32 value)
 {
 	return -ENODEV;
 }