[PATCH v3 3/7] pm80xx: Add sysfs attribute to track iop0 count

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

From: Vishakha Channapattan <vishakhavc@google.com>

A new sysfs variable 'ctl_iop0_count' is being introduced that tells if
the controller is alive by indicating controller ticks. If on subsequent
run we see the ticks changing that indicates that controller is not
dead.

Tested: Using 'ctl_iop0_count' sysfs variable we can see ticks
incrementing
mvae14:~# cat  /sys/class/scsi_host/host*/ctl_iop0_count
0x000000a3
0x000001db
0x000001e4
0x000001e7

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 890d6faf18e9..dd546d2c35d7 100644
--- a/drivers/scsi/pm8001/pm8001_ctl.c
+++ b/drivers/scsi/pm8001/pm8001_ctl.c
@@ -941,6 +941,29 @@ static ssize_t ctl_raae_count_show(struct device *cdev,
 }
 static DEVICE_ATTR_RO(ctl_raae_count);
 
+/**
+ * ctl_iop0_count_show - controller iop0 count check
+ * @cdev: pointer to embedded class device
+ * @buf: the buffer returned
+ *
+ * A sysfs 'read-only' shost attribute.
+ */
+
+static ssize_t ctl_iop0_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 iop0cnt;
+	int c;
+
+	iop0cnt = pm8001_mr32(pm8001_ha->general_stat_tbl_addr, 16);
+	c = sysfs_emit(buf, "0x%08x\n", iop0cnt);
+	return c;
+}
+static DEVICE_ATTR_RO(ctl_iop0_count);
+
 struct device_attribute *pm8001_host_attrs[] = {
 	&dev_attr_interface_rev,
 	&dev_attr_controller_fatal_error,
@@ -966,6 +989,7 @@ struct device_attribute *pm8001_host_attrs[] = {
 	&dev_attr_inc_fw_ver,
 	&dev_attr_ctl_mpi_state,
 	&dev_attr_ctl_raae_count,
+	&dev_attr_ctl_iop0_count,
 	NULL,
 };
 
-- 
2.16.3