[PATCH 3/3] firmware: xilinx: Add sysfs to get last reset reason

[Amit Sunil Dhamne <amit.sunil.dhamne@xilinx.com>]

From: Tejas Patel <tejas.patel@xilinx.com>

Add sysfs to get last reset reason.

Signed-off-by: Tejas Patel <tejas.patel@xilinx.com>
Signed-off-by: Amit Sunil Dhamne <amit.sunil.dhamne@xilinx.com>
---
 .../ABI/stable/sysfs-driver-firmware-zynqmp        | 13 ++++++++
 drivers/firmware/xilinx/zynqmp.c                   | 37 ++++++++++++++++++++++
 include/linux/firmware/xlnx-zynqmp.h               | 11 +++++++
 3 files changed, 61 insertions(+)

diff --git a/Documentation/ABI/stable/sysfs-driver-firmware-zynqmp b/Documentation/ABI/stable/sysfs-driver-firmware-zynqmp
index 00fa04c..96a5760 100644
--- a/Documentation/ABI/stable/sysfs-driver-firmware-zynqmp
+++ b/Documentation/ABI/stable/sysfs-driver-firmware-zynqmp
@@ -101,3 +101,16 @@ Description:
                # echo 0 > /sys/devices/platform/firmware\:zynqmp-firmware/health_status

 Users:         Xilinx
+
+What:          /sys/devices/platform/firmware\:zynqmp-firmware/last_reset_reason
+Date:          June 2020
+KernelVersion: 5.9.0
+Contact:       "Tejas Patel" <tejasp@xilinx.com>
+Description:
+               This sysfs interface allows to get last reset reason.
+
+               Usage:
+               Get last reset reason
+               # cat /sys/devices/platform/firmware\:zynqmp-firmware/last_reset_reason
+
+Users:         Xilinx
diff --git a/drivers/firmware/xilinx/zynqmp.c b/drivers/firmware/xilinx/zynqmp.c
index c5db34f..f590856 100644
--- a/drivers/firmware/xilinx/zynqmp.c
+++ b/drivers/firmware/xilinx/zynqmp.c
@@ -1266,6 +1266,42 @@ static DEVICE_ATTR_RW(pggs1);
 static DEVICE_ATTR_RW(pggs2);
 static DEVICE_ATTR_RW(pggs3);

+static ssize_t last_reset_reason_show(struct device *device,
+                                     struct device_attribute *attr, char *buf)
+{
+       int ret;
+       u32 ret_payload[PAYLOAD_ARG_CNT];
+
+       ret = zynqmp_pm_get_last_reset_reason(ret_payload);
+       if (-EINVAL == ret)
+               return sprintf(buf, "Feature not supported\n");
+       else if (ret)
+               return ret;
+
+       switch (ret_payload[1]) {
+       case PM_RESET_REASON_EXT_POR:
+               return sprintf(buf, "ext_por\n");
+       case PM_RESET_REASON_SW_POR:
+               return sprintf(buf, "sw_por\n");
+       case PM_RESET_REASON_SLR_POR:
+               return sprintf(buf, "sl_por\n");
+       case PM_RESET_REASON_ERR_POR:
+               return sprintf(buf, "err_por\n");
+       case PM_RESET_REASON_DAP_SRST:
+               return sprintf(buf, "dap_srst\n");
+       case PM_RESET_REASON_ERR_SRST:
+               return sprintf(buf, "err_srst\n");
+       case PM_RESET_REASON_SW_SRST:
+               return sprintf(buf, "sw_srst\n");
+       case PM_RESET_REASON_SLR_SRST:
+               return sprintf(buf, "slr_srst\n");
+       default:
+               return sprintf(buf, "unknown reset\n");
+       }
+}
+
+static DEVICE_ATTR_RO(last_reset_reason);
+
 static struct attribute *zynqmp_firmware_attrs[] = {
        &dev_attr_ggs0.attr,
        &dev_attr_ggs1.attr,
@@ -1277,6 +1313,7 @@ static struct attribute *zynqmp_firmware_attrs[] = {
        &dev_attr_pggs3.attr,
        &dev_attr_shutdown_scope.attr,
        &dev_attr_health_status.attr,
+       &dev_attr_last_reset_reason.attr,
        NULL,
 };

diff --git a/include/linux/firmware/xlnx-zynqmp.h b/include/linux/firmware/xlnx-zynqmp.h
index 90c8664..f7cb0a9 100644
--- a/include/linux/firmware/xlnx-zynqmp.h
+++ b/include/linux/firmware/xlnx-zynqmp.h
@@ -302,6 +302,17 @@ enum zynqmp_pm_shutdown_subtype {
        ZYNQMP_PM_SHUTDOWN_SUBTYPE_SYSTEM,
 };

+enum pm_reset_reason {
+       PM_RESET_REASON_EXT_POR = 0,
+       PM_RESET_REASON_SW_POR = 1,
+       PM_RESET_REASON_SLR_POR = 2,
+       PM_RESET_REASON_ERR_POR = 3,
+       PM_RESET_REASON_DAP_SRST = 7,
+       PM_RESET_REASON_ERR_SRST = 8,
+       PM_RESET_REASON_SW_SRST = 9,
+       PM_RESET_REASON_SLR_SRST = 10,
+};
+
 /**
  * struct zynqmp_pm_query_data - PM query data
  * @qid:       query ID
--
2.7.4

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