[PATCH V2 3/4] scsi: ufs-debugfs: Add user-defined exception_event_mask

[Adrian Hunter]

Allow users to enable specific exception events via debugfs.

The bits enabled by the driver ee_drv_ctrl are separated from the bits
enabled by the user ee_usr_ctrl. The control mask ee_mask_ctrl is the
logical-or of those two. A mutex is needed to ensure that the masks match
what was written to the device.

Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
---
 drivers/scsi/ufs/ufs-debugfs.c | 46 ++++++++++++++++++
 drivers/scsi/ufs/ufshcd.c      | 86 +++++++++++++++++++++-------------
 drivers/scsi/ufs/ufshcd.h      | 22 ++++++++-
 3 files changed, 120 insertions(+), 34 deletions(-)

diff --git a/drivers/scsi/ufs/ufs-debugfs.c b/drivers/scsi/ufs/ufs-debugfs.c
index dee98dc72d29..59729073b569 100644
--- a/drivers/scsi/ufs/ufs-debugfs.c
+++ b/drivers/scsi/ufs/ufs-debugfs.c
@@ -44,10 +44,56 @@ static int ufs_debugfs_stats_show(struct seq_file *s, void *data)
 }
 DEFINE_SHOW_ATTRIBUTE(ufs_debugfs_stats);
 
+static int ee_usr_mask_get(void *data, u64 *val)
+{
+	struct ufs_hba *hba = data;
+
+	*val = hba->ee_usr_mask;
+	return 0;
+}
+
+static int ufs_debugfs_get_user_access(struct ufs_hba *hba)
+__acquires(&hba->host_sem)
+{
+	down(&hba->host_sem);
+	if (!ufshcd_is_user_access_allowed(hba)) {
+		up(&hba->host_sem);
+		return -EBUSY;
+	}
+	pm_runtime_get_sync(hba->dev);
+	return 0;
+}
+
+static void ufs_debugfs_put_user_access(struct ufs_hba *hba)
+__releases(&hba->host_sem)
+{
+	pm_runtime_put_sync(hba->dev);
+	up(&hba->host_sem);
+}
+
+static int ee_usr_mask_set(void *data, u64 val)
+{
+	struct ufs_hba *hba = data;
+	int err;
+
+	if (val & ~(u64)MASK_EE_STATUS)
+		return -EINVAL;
+	err = ufs_debugfs_get_user_access(hba);
+	if (err)
+		return err;
+	err = ufshcd_update_ee_usr_mask(hba, val, MASK_EE_STATUS);
+	ufs_debugfs_put_user_access(hba);
+	return err;
+}
+
+DEFINE_DEBUGFS_ATTRIBUTE(ee_usr_mask_fops, ee_usr_mask_get, ee_usr_mask_set, "%#llx\n");
+
 void ufs_debugfs_hba_init(struct ufs_hba *hba)
 {
 	hba->debugfs_root = debugfs_create_dir(dev_name(hba->dev), ufs_debugfs_root);
 	debugfs_create_file("stats", 0400, hba->debugfs_root, hba, &ufs_debugfs_stats_fops);
+	debugfs_create_file("exception_event_mask", 0600, hba->debugfs_root,
+			    hba, &ee_usr_mask_fops);
 }
 
 void ufs_debugfs_hba_exit(struct ufs_hba *hba)
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index d6fdce655388..065a662e7886 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -5160,6 +5160,46 @@ static irqreturn_t ufshcd_transfer_req_compl(struct ufs_hba *hba)
 	}
 }
 
+static int __ufshcd_write_ee_control(struct ufs_hba *hba, u32 ee_ctrl_mask)
+{
+	return ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_WRITE_ATTR,
+				       QUERY_ATTR_IDN_EE_CONTROL, 0, 0,
+				       &ee_ctrl_mask);
+}
+
+static int ufshcd_write_ee_control(struct ufs_hba *hba)
+{
+	int err;
+
+	mutex_lock(&hba->ee_ctrl_mutex);
+	err = __ufshcd_write_ee_control(hba, hba->ee_ctrl_mask);
+	mutex_unlock(&hba->ee_ctrl_mutex);
+	if (err)
+		dev_err(hba->dev, "%s: failed to write ee control %d\n",
+			__func__, err);
+	return err;
+}
+
+int ufshcd_update_ee_control(struct ufs_hba *hba, u16 *mask, u16 *other_mask,
+			     u16 set, u16 clr)
+{
+	u16 new_mask, ee_ctrl_mask;
+	int err = 0;
+
+	mutex_lock(&hba->ee_ctrl_mutex);
+	new_mask = (*mask & ~clr) | set;
+	ee_ctrl_mask = new_mask | *other_mask;
+	if (ee_ctrl_mask != hba->ee_ctrl_mask)
+		err = __ufshcd_write_ee_control(hba, ee_ctrl_mask);
+	/* Still need to update 'mask' even if 'ee_ctrl_mask' was unchanged */
+	if (!err) {
+		hba->ee_ctrl_mask = ee_ctrl_mask;
+		*mask = new_mask;
+	}
+	mutex_unlock(&hba->ee_ctrl_mutex);
+	return err;
+}
+
 /**
  * ufshcd_disable_ee - disable exception event
  * @hba: per-adapter instance
@@ -5170,22 +5210,9 @@ static irqreturn_t ufshcd_transfer_req_compl(struct ufs_hba *hba)
  *
  * Returns zero on success, non-zero error value on failure.
  */
-static int ufshcd_disable_ee(struct ufs_hba *hba, u16 mask)
+static inline int ufshcd_disable_ee(struct ufs_hba *hba, u16 mask)
 {
-	int err = 0;
-	u32 val;
-
-	if (!(hba->ee_ctrl_mask & mask))
-		goto out;
-
-	val = hba->ee_ctrl_mask & ~mask;
-	val &= MASK_EE_STATUS;
-	err = ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_WRITE_ATTR,
-			QUERY_ATTR_IDN_EE_CONTROL, 0, 0, &val);
-	if (!err)
-		hba->ee_ctrl_mask &= ~mask;
-out:
-	return err;
+	return ufshcd_update_ee_drv_mask(hba, 0, mask);
 }
 
 /**
@@ -5198,22 +5225,9 @@ static int ufshcd_disable_ee(struct ufs_hba *hba, u16 mask)
  *
  * Returns zero on success, non-zero error value on failure.
  */
-static int ufshcd_enable_ee(struct ufs_hba *hba, u16 mask)
+static inline int ufshcd_enable_ee(struct ufs_hba *hba, u16 mask)
 {
-	int err = 0;
-	u32 val;
-
-	if (hba->ee_ctrl_mask & mask)
-		goto out;
-
-	val = hba->ee_ctrl_mask | mask;
-	val &= MASK_EE_STATUS;
-	err = ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_WRITE_ATTR,
-			QUERY_ATTR_IDN_EE_CONTROL, 0, 0, &val);
-	if (!err)
-		hba->ee_ctrl_mask |= mask;
-out:
-	return err;
+	return ufshcd_update_ee_drv_mask(hba, mask, 0);
 }
 
 /**
@@ -5618,9 +5632,7 @@ static void ufshcd_exception_event_handler(struct work_struct *work)
 
 	trace_ufshcd_exception_event(dev_name(hba->dev), status);
 
-	status &= hba->ee_ctrl_mask;
-
-	if (status & MASK_EE_URGENT_BKOPS)
+	if (status & hba->ee_drv_mask & MASK_EE_URGENT_BKOPS)
 		ufshcd_bkops_exception_event_handler(hba);
 
 out:
@@ -7921,6 +7933,8 @@ static int ufshcd_probe_hba(struct ufs_hba *hba, bool async)
 	ufshcd_set_active_icc_lvl(hba);
 
 	ufshcd_wb_config(hba);
+	if (hba->ee_usr_mask)
+		ufshcd_write_ee_control(hba);
 	/* Enable Auto-Hibernate if configured */
 	ufshcd_auto_hibern8_enable(hba);
 
@@ -8918,6 +8932,9 @@ static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 		 */
 		ufshcd_urgent_bkops(hba);
 
+	if (hba->ee_usr_mask)
+		ufshcd_write_ee_control(hba);
+
 	hba->clk_gating.is_suspended = false;
 
 	if (ufshcd_is_clkscaling_supported(hba))
@@ -9355,6 +9372,9 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
 	/* Initialize mutex for device management commands */
 	mutex_init(&hba->dev_cmd.lock);
 
+	/* Initialize mutex for exception event control */
+	mutex_init(&hba->ee_ctrl_mutex);
+
 	init_rwsem(&hba->clk_scaling_lock);
 
 	ufshcd_init_clk_gating(hba);
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index ee61f821f75d..9b7413f35def 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -773,7 +773,10 @@ struct ufs_hba {
 	u32 ufshcd_state;
 	u32 eh_flags;
 	u32 intr_mask;
-	u16 ee_ctrl_mask;
+	u16 ee_ctrl_mask; /* Exception event mask */
+	u16 ee_drv_mask;  /* Exception event mask for driver */
+	u16 ee_usr_mask;  /* Exception event mask for user (via debugfs) */
+	struct mutex ee_ctrl_mutex;
 	bool is_powered;
 	bool shutting_down;
 	struct semaphore host_sem;
@@ -1285,4 +1288,21 @@ static inline u8 ufshcd_scsi_to_upiu_lun(unsigned int scsi_lun)
 int ufshcd_dump_regs(struct ufs_hba *hba, size_t offset, size_t len,
 		     const char *prefix);
 
+int ufshcd_update_ee_control(struct ufs_hba *hba, u16 *mask, u16 *other_mask,
+			     u16 set, u16 clr);
+
+static inline int ufshcd_update_ee_drv_mask(struct ufs_hba *hba,
+					    u16 set, u16 clr)
+{
+	return ufshcd_update_ee_control(hba, &hba->ee_drv_mask,
+					&hba->ee_usr_mask, set, clr);
+}
+
+static inline int ufshcd_update_ee_usr_mask(struct ufs_hba *hba,
+					    u16 set, u16 clr)
+{
+	return ufshcd_update_ee_control(hba, &hba->ee_usr_mask,
+					&hba->ee_drv_mask, set, clr);
+}
+
 #endif /* End of Header */
-- 
2.17.1