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

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Message-Id: <1572439064-28785-2-git-send-email-cang@codeaurora.org>
Date:   Wed, 30 Oct 2019 05:37:42 -0700
From:   Can Guo <cang@...eaurora.org>
To:     asutoshd@...eaurora.org, nguyenb@...eaurora.org,
        rnayak@...eaurora.org, linux-scsi@...r.kernel.org,
        kernel-team@...roid.com, saravanak@...gle.com, salyzyn@...gle.com,
        cang@...eaurora.org
Cc:     Alim Akhtar <alim.akhtar@...sung.com>,
        Avri Altman <avri.altman@....com>,
        Pedro Sousa <pedrom.sousa@...opsys.com>,
        "James E.J. Bottomley" <jejb@...ux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        Stanley Chu <stanley.chu@...iatek.com>,
        Bean Huo <beanhuo@...ron.com>,
        Tomas Winkler <tomas.winkler@...el.com>,
        Subhash Jadavani <subhashj@...eaurora.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Arnd Bergmann <arnd@...db.de>,
        linux-kernel@...r.kernel.org (open list)
Subject: [PATCH v1 1/2] scsi: ufs: Introduce bus voting vendor ops

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@...eaurora.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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