[PATCH v1 1/2] scsi: ufs: Introduce bus voting vendor ops

[Can Guo <cang@codeaurora.org>]

Some vendors need to vote for bus bandwidth when bus clocks are changed,
hence introduce the bus voting vendor ops so that UFS driver can use it.

Signed-off-by: Can Guo <cang@codeaurora.org>
---
 drivers/scsi/ufs/ufshcd.c | 19 ++++++++++++++++++-
 drivers/scsi/ufs/ufshcd.h |  9 +++++++++
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index c28c144..ec13aaf 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -7289,6 +7289,13 @@ static int __ufshcd_setup_clocks(struct ufs_hba *hba, bool on,
 	if (list_empty(head))
 		goto out;
 
+	/* call vendor specific bus vote before enabling the clocks */
+	if (on) {
+		ret = ufshcd_vops_set_bus_vote(hba, on);
+		if (ret)
+			return ret;
+	}
+
 	/*
 	 * vendor specific setup_clocks ops may depend on clocks managed by
 	 * this standard driver hence call the vendor specific setup_clocks
@@ -7330,11 +7337,21 @@ static int __ufshcd_setup_clocks(struct ufs_hba *hba, bool on,
 	if (on) {
 		ret = ufshcd_vops_setup_clocks(hba, on, POST_CHANGE);
 		if (ret)
-			return ret;
+			goto out;
 	}
 
+	/*
+	 * call vendor specific bus vote to remove the vote after
+	 * disabling the clocks.
+	 */
+	if (!on)
+		ret = ufshcd_vops_set_bus_vote(hba, on);
+
 out:
 	if (ret) {
+		if (on)
+			/* Can't do much if this fails */
+			(void) ufshcd_vops_set_bus_vote(hba, false);
 		list_for_each_entry(clki, head, list) {
 			if (!IS_ERR_OR_NULL(clki->clk) && clki->enabled)
 				clk_disable_unprepare(clki->clk);
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index e0fe247..7eb4174 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -297,6 +297,7 @@ struct ufs_pwr_mode_info {
  * @suspend: called during host controller PM callback
  * @resume: called during host controller PM callback
  * @dbg_register_dump: used to dump controller debug information
+ * @set_bus_vote: called to vote for the required bus bandwidth
  * @phy_initialization: used to initialize phys
  * @device_reset: called to issue a reset pulse on the UFS device
  */
@@ -326,6 +327,7 @@ struct ufs_hba_variant_ops {
 	int     (*suspend)(struct ufs_hba *, enum ufs_pm_op);
 	int     (*resume)(struct ufs_hba *, enum ufs_pm_op);
 	void	(*dbg_register_dump)(struct ufs_hba *hba);
+	int	(*set_bus_vote)(struct ufs_hba *, bool);
 	int	(*phy_initialization)(struct ufs_hba *);
 	void	(*device_reset)(struct ufs_hba *hba);
 };
@@ -1082,6 +1084,13 @@ static inline void ufshcd_vops_dbg_register_dump(struct ufs_hba *hba)
 		hba->vops->dbg_register_dump(hba);
 }
 
+static inline int ufshcd_vops_set_bus_vote(struct ufs_hba *hba, bool on)
+{
+	if (hba->vops && hba->vops->set_bus_vote)
+		return hba->vops->set_bus_vote(hba, on);
+	return 0;
+}
+
 static inline void ufshcd_vops_device_reset(struct ufs_hba *hba)
 {
 	if (hba->vops && hba->vops->device_reset)
-- 
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