scsi: ufs: core: Add temperature notification exception handling

The device may notify the host of an extreme temperature by using the
exception event mechanism. The exception can be raised when the device’s
Tcase temperature is either too high or too low.

It is essentially up to the platform to decide what further actions need to
be taken. leave a placeholder for a designated vop for that.

Link: https://lore.kernel.org/r/20210915060407.40-3-avri.altman@wdc.com
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Bean Huo <beanhuo@micron.com>
Reviewed-by: Daejun Park <daejun7.park@samsung.com>
Signed-off-by: Avri Altman <avri.altman@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/ufs/ufs-hwmon.c

@@ -196,3 +196,15 @@ void ufs_hwmon_remove(struct ufs_hba *hba)
 	hba->hwmon_device = NULL;
 	kfree(data);
 }
+
+void ufs_hwmon_notify_event(struct ufs_hba *hba, u8 ee_mask)
+{
+	if (!hba->hwmon_device)
+		return;
+
+	if (ee_mask & MASK_EE_TOO_HIGH_TEMP)
+		hwmon_notify_event(hba->hwmon_device, hwmon_temp, hwmon_temp_max_alarm, 0);
+
+	if (ee_mask & MASK_EE_TOO_LOW_TEMP)
+		hwmon_notify_event(hba->hwmon_device, hwmon_temp, hwmon_temp_min_alarm, 0);
+}

drivers/scsi/ufs/ufshcd.c

@@ -5642,6 +5642,24 @@ out:
 				__func__, err);
 }
 
+static void ufshcd_temp_exception_event_handler(struct ufs_hba *hba, u16 status)
+{
+	u32 value;
+
+	if (ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_READ_ATTR,
+				QUERY_ATTR_IDN_CASE_ROUGH_TEMP, 0, 0, &value))
+		return;
+
+	dev_info(hba->dev, "exception Tcase %d\n", value - 80);
+
+	ufs_hwmon_notify_event(hba, status & MASK_EE_URGENT_TEMP);
+
+	/*
+	 * A placeholder for the platform vendors to add whatever additional
+	 * steps required
+	 */
+}
+
 static int __ufshcd_wb_toggle(struct ufs_hba *hba, bool set, enum flag_idn idn)
 {
 	u8 index;
@@ -5821,6 +5839,9 @@ static void ufshcd_exception_event_handler(struct work_struct *work)
 	if (status & hba->ee_drv_mask & MASK_EE_URGENT_BKOPS)
 		ufshcd_bkops_exception_event_handler(hba);
 
+	if (status & hba->ee_drv_mask & MASK_EE_URGENT_TEMP)
+		ufshcd_temp_exception_event_handler(hba, status);
+
 	ufs_debugfs_exception_event(hba, status);
 out:
 	ufshcd_scsi_unblock_requests(hba);

drivers/scsi/ufs/ufshcd.h

@@ -1062,9 +1062,11 @@ static inline u8 ufshcd_wb_get_query_index(struct ufs_hba *hba)
 #ifdef CONFIG_SCSI_UFS_HWMON
 void ufs_hwmon_probe(struct ufs_hba *hba, u8 mask);
 void ufs_hwmon_remove(struct ufs_hba *hba);
+void ufs_hwmon_notify_event(struct ufs_hba *hba, u8 ee_mask);
 #else
 static inline void ufs_hwmon_probe(struct ufs_hba *hba, u8 mask) {}
 static inline void ufs_hwmon_remove(struct ufs_hba *hba) {}
+static inline void ufs_hwmon_notify_event(struct ufs_hba *hba, u8 ee_mask) {}
 #endif
 
 #ifdef CONFIG_PM