linux-kernel - [PATCH v2 4/4] firmware: xilinx: Add sysfs and IOCTL to set boot health status

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Date:   Wed,  8 Jan 2020 15:54:23 -0800
From:   Jolly Shah <jolly.shah@...inx.com>
To:     ard.biesheuvel@...aro.org, mingo@...nel.org,
        gregkh@...uxfoundation.org, matt@...eblueprint.co.uk,
        sudeep.holla@....com, hkallweit1@...il.com, keescook@...omium.org,
        dmitry.torokhov@...il.com, michal.simek@...inx.com
Cc:     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>
Subject: [PATCH v2 4/4] firmware: xilinx: Add sysfs and IOCTL to set boot health status

From: Rajan Vaja <rajan.vaja@...inx.com>

Add sysfs interface to set boot health status from user space.
Add IOCTL ID 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>
---
Changes in v2:
 - Updated Linux kernel version in documentation.
 - Used DEVICE_ATTR_* and ATTRIBUTE_GROUPS macros.
 - Updated Signed-off-by sequence.
---
 Documentation/ABI/stable/sysfs-firmware-zynqmp | 21 +++++++++++++
 drivers/firmware/xilinx/zynqmp.c               | 41 ++++++++++++++++++++++++++
 include/linux/firmware/xlnx-zynqmp.h           |  2 ++
 3 files changed, 64 insertions(+)

diff --git a/Documentation/ABI/stable/sysfs-firmware-zynqmp b/Documentation/ABI/stable/sysfs-firmware-zynqmp
index f41e9c5..3f44a3c 100644
--- a/Documentation/ABI/stable/sysfs-firmware-zynqmp
+++ b/Documentation/ABI/stable/sysfs-firmware-zynqmp
@@ -80,3 +80,24 @@ Description:
 		# echo "subsystem" > /sys/firmware/zynqmp/shutdown_scope
 
 Users:		Xilinx
+
+What:		/sys/firmware/zynqmp/health_status
+Date:		April 2018
+KernelVersion:	5.5
+Contact:	"Rajan Vaja" <rajanv@...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/firmware/zynqmp/health_status
+
+		Unset healthy bit
+		# echo 0 > /sys/firmware/zynqmp/health_status
+
+Users:		Xilinx
diff --git a/drivers/firmware/xilinx/zynqmp.c b/drivers/firmware/xilinx/zynqmp.c
index ef7d107..2a77c90 100644
--- a/drivers/firmware/xilinx/zynqmp.c
+++ b/drivers/firmware/xilinx/zynqmp.c
@@ -477,6 +477,7 @@ static inline int zynqmp_is_valid_ioctl(u32 ioctl_id)
 	case IOCTL_READ_GGS:
 	case IOCTL_WRITE_PGGS:
 	case IOCTL_READ_PGGS:
+	case IOCTL_SET_BOOT_HEALTH_STATUS:
 		return 1;
 	default:
 		return 0;
@@ -861,8 +862,48 @@ static ssize_t shutdown_scope_store(struct device *device,
 
 static DEVICE_ATTR_RW(shutdown_scope);
 
+/**
+ * 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/firmware/zynqmp/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_ioctl(0, IOCTL_SET_BOOT_HEALTH_STATUS, value, 0, NULL);
+	if (ret) {
+		pr_err("unable to set healthy bit value to %u\n", value);
+		return ret;
+	}
+
+	return count;
+}
+
+static DEVICE_ATTR_WO(health_status);
+
 static struct attribute *zynqmp_attrs[] = {
 	&dev_attr_shutdown_scope.attr,
+	&dev_attr_health_status.attr,
 	NULL,
 };
 
diff --git a/include/linux/firmware/xlnx-zynqmp.h b/include/linux/firmware/xlnx-zynqmp.h
index e4f83c6..0554054 100644
--- a/include/linux/firmware/xlnx-zynqmp.h
+++ b/include/linux/firmware/xlnx-zynqmp.h
@@ -106,6 +106,8 @@ enum pm_ioctl_id {
 	IOCTL_READ_GGS,
 	IOCTL_WRITE_PGGS,
 	IOCTL_READ_PGGS,
+	/* Set healthy bit value */
+	IOCTL_SET_BOOT_HEALTH_STATUS = 17,
 };
 
 enum pm_query_id {
-- 
2.7.4