scsi: ufs: Introduce event_notify variant function

Introduce event_notify variant function to allow vendor to get notification
of important events and connect to any proprietary debugging facilities.

Link: https://lore.kernel.org/r/20201205115901.26815-4-stanley.chu@mediatek.com
Reviewed-by: Asutosh Das <asutoshd@codeaurora.org>
Reviewed-by: Can Guo <cang@codeaurora.org>
Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/ufs/ufshcd.c

@@ -4480,6 +4480,8 @@ void ufshcd_update_evt_hist(struct ufs_hba *hba, u32 id, u32 val)
 	e->val[e->pos] = val;
 	e->tstamp[e->pos] = ktime_get();
 	e->pos = (e->pos + 1) % UFS_EVENT_HIST_LENGTH;
+
+	ufshcd_vops_event_notify(hba, id, &val);
 }
 EXPORT_SYMBOL_GPL(ufshcd_update_evt_hist);
 

drivers/scsi/ufs/ufshcd.h

@@ -320,6 +320,7 @@ struct ufs_pwr_mode_info {
  * @phy_initialization: used to initialize phys
  * @device_reset: called to issue a reset pulse on the UFS device
  * @program_key: program or evict an inline encryption key
+ * @event_notify: called to notify important events
  */
 struct ufs_hba_variant_ops {
 	const char *name;
@@ -355,6 +356,8 @@ struct ufs_hba_variant_ops {
 					void *data);
 	int	(*program_key)(struct ufs_hba *hba,
 			       const union ufs_crypto_cfg_entry *cfg, int slot);
+	void	(*event_notify)(struct ufs_hba *hba,
+				enum ufs_event_type evt, void *data);
 };
 
 /* clock gating state  */
@@ -1102,6 +1105,14 @@ static inline int ufshcd_vops_clk_scale_notify(struct ufs_hba *hba,
 	return 0;
 }
 
+static inline void ufshcd_vops_event_notify(struct ufs_hba *hba,
+					    enum ufs_event_type evt,
+					    void *data)
+{
+	if (hba->vops && hba->vops->event_notify)
+		hba->vops->event_notify(hba, evt, data);
+}
+
 static inline int ufshcd_vops_setup_clocks(struct ufs_hba *hba, bool on,
 					enum ufs_notify_change_status status)
 {