[PATCH v3 2/7] pm80xx: Add sysfs attribute to track RAAE count

[Viswas G <Viswas.G@microchip.com>]

From: Vishakha Channapattan <vishakhavc@google.com>

A new sysfs variable 'ctl_raae_count' is being introduced that tells if
the controller is alive by indicating controller ticks. If on subsequent
run we see the ticks changing in RAAE count that indicates that
controller is not dead.

Tested: Using 'ctl_raae_count' sysfs variable we can see ticks
incrementing
mvae14:~# cat  /sys/class/scsi_host/host*/ctl_raae_count
0x00002245
0x00002253
0x0000225e

Signed-off-by: Vishakha Channapattan <vishakhavc@google.com>
Signed-off-by: Viswas G <Viswas.G@microchip.com>
Signed-off-by: Ruksar Devadi <Ruksar.devadi@microchip.com>
Signed-off-by: Ashokkumar N <Ashokkumar.N@microchip.com>
Signed-off-by: Radha Ramachandran <radha@google.com>
Acked-by: Jack Wang <jinpu.wang@ionos.com>
---
 drivers/scsi/pm8001/pm8001_ctl.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/scsi/pm8001/pm8001_ctl.c b/drivers/scsi/pm8001/pm8001_ctl.c
index 6b6b774c455e..890d6faf18e9 100644
--- a/drivers/scsi/pm8001/pm8001_ctl.c
+++ b/drivers/scsi/pm8001/pm8001_ctl.c
@@ -918,6 +918,29 @@ static ssize_t ctl_mpi_state_show(struct device *cdev,
 }
 static DEVICE_ATTR_RO(ctl_mpi_state);
 
+/**
+ * ctl_raae_count_show - controller raae count check
+ * @cdev: pointer to embedded class device
+ * @buf: the buffer returned
+ *
+ * A sysfs 'read-only' shost attribute.
+ */
+
+static ssize_t ctl_raae_count_show(struct device *cdev,
+		struct device_attribute *attr, char *buf)
+{
+	struct Scsi_Host *shost = class_to_shost(cdev);
+	struct sas_ha_struct *sha = SHOST_TO_SAS_HA(shost);
+	struct pm8001_hba_info *pm8001_ha = sha->lldd_ha;
+	unsigned int raaecnt;
+	int c;
+
+	raaecnt = pm8001_mr32(pm8001_ha->general_stat_tbl_addr, 12);
+	c = sysfs_emit(buf, "0x%08x\n", raaecnt);
+	return c;
+}
+static DEVICE_ATTR_RO(ctl_raae_count);
+
 struct device_attribute *pm8001_host_attrs[] = {
 	&dev_attr_interface_rev,
 	&dev_attr_controller_fatal_error,
@@ -942,6 +965,7 @@ struct device_attribute *pm8001_host_attrs[] = {
 	&dev_attr_ila_version,
 	&dev_attr_inc_fw_ver,
 	&dev_attr_ctl_mpi_state,
+	&dev_attr_ctl_raae_count,
 	NULL,
 };
 
-- 
2.16.3