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Subject[PATCH 1/1] scsi: ufshcd: fix possible unclocked register access
Date
From: Subhash Jadavani <subhashj@codeaurora.org>

vendor specific setup_clocks ops may depend on clocks managed by ufshcd
driver so if the vendor specific setup_clocks callback is called when
the required clocks are turned off, it results into unclocked register
access.

This change make sure that required clocks are enabled before vendor
specific setup_clocks callback is called.

Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Venkat Gopalakrishnan <venkatg@codeaurora.org>
Signed-off-by: Can Guo <cang@codeaurora.org>
Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
---
drivers/scsi/ufs/ufshcd.c | 26 ++++++++++++++++++++------
1 file changed, 20 insertions(+), 6 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 8af2af3..c5ee686 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -6763,9 +6763,16 @@ static int __ufshcd_setup_clocks(struct ufs_hba *hba, bool on,
if (list_empty(head))
goto out;

- ret = ufshcd_vops_setup_clocks(hba, on, PRE_CHANGE);
- 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
+ * before disabling the clocks managed here.
+ */
+ if (!on) {
+ ret = ufshcd_vops_setup_clocks(hba, on, PRE_CHANGE);
+ if (ret)
+ return ret;
+ }

list_for_each_entry(clki, head, list) {
if (!IS_ERR_OR_NULL(clki->clk)) {
@@ -6789,9 +6796,16 @@ static int __ufshcd_setup_clocks(struct ufs_hba *hba, bool on,
}
}

- ret = ufshcd_vops_setup_clocks(hba, on, POST_CHANGE);
- 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
+ * after enabling the clocks managed here.
+ */
+ if (on) {
+ ret = ufshcd_vops_setup_clocks(hba, on, POST_CHANGE);
+ if (ret)
+ return ret;
+ }

out:
if (ret) {
--
Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.
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