scsi: ufshcd: Fix possible unclocked register access

Vendor specific setup_clocks callback may require the clocks managed by
ufshcd driver to be ON. So if the vendor specific setup_clocks callback
is called while the required clocks are turned off, it could result into
unclocked register access.

To prevent possible unclock register access, this change adds one more
argument to setup_clocks callback to let it know whether it is called
pre/post the clock changes by core driver.

Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
Reviewed-by: Kiwoong Kim <kwmad.kim@samsung.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/ufs/ufs-qcom.c b/drivers/scsi/ufs/ufs-qcom.c
index 3aedf73f1131369efe18e4feb5ce793507d4714d..3c4f602eecd2b601985b62124c33d84617ac7425 100644 (file)
--- a/drivers/scsi/ufs/ufs-qcom.c
+++ b/drivers/scsi/ufs/ufs-qcom.c
@@ -1094,10 +1094,12 @@ static void ufs_qcom_set_caps(struct ufs_hba *hba)
  * ufs_qcom_setup_clocks - enables/disable clocks
  * @hba: host controller instance
  * @on: If true, enable clocks else disable them.
+ * @status: PRE_CHANGE or POST_CHANGE notify
  *
  * Returns 0 on success, non-zero on failure.
  */
-static int ufs_qcom_setup_clocks(struct ufs_hba *hba, bool on)
+static int ufs_qcom_setup_clocks(struct ufs_hba *hba, bool on,
+                                enum ufs_notify_change_status status)
 {
        struct ufs_qcom_host *host = ufshcd_get_variant(hba);
        int err;
@@ -1111,7 +1113,7 @@ static int ufs_qcom_setup_clocks(struct ufs_hba *hba, bool on)
        if (!host)
                return 0;
 
-       if (on) {
+       if (on && (status == POST_CHANGE)) {
                err = ufs_qcom_phy_enable_iface_clk(host->generic_phy);
                if (err)
                        goto out;
@@ -1130,7 +1132,7 @@ static int ufs_qcom_setup_clocks(struct ufs_hba *hba, bool on)
                if (vote == host->bus_vote.min_bw_vote)
                        ufs_qcom_update_bus_bw_vote(host);
 
-       } else {
+       } else if (!on && (status == PRE_CHANGE)) {
 
                /* M-PHY RMMI interface clocks can be turned off */
                ufs_qcom_phy_disable_iface_clk(host->generic_phy);
@@ -1254,7 +1256,7 @@ static int ufs_qcom_init(struct ufs_hba *hba)
        ufs_qcom_set_caps(hba);
        ufs_qcom_advertise_quirks(hba);
 
-       ufs_qcom_setup_clocks(hba, true);
+       ufs_qcom_setup_clocks(hba, true, POST_CHANGE);
 
        if (hba->dev->id < MAX_UFS_QCOM_HOSTS)
                ufs_qcom_hosts[hba->dev->id] = host;

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 05c745663c103a7ddb70d4e6845702a6c08ebd08..571a2f64a01d71e654ed91a87779ac4db2f5791c 100644 (file)
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -5389,6 +5389,10 @@ static int __ufshcd_setup_clocks(struct ufs_hba *hba, bool on,
        if (!head || list_empty(head))
                goto out;
 
+       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)) {
                        if (skip_ref_clk && !strcmp(clki->name, "ref_clk"))
@@ -5410,7 +5414,10 @@ static int __ufshcd_setup_clocks(struct ufs_hba *hba, bool on,
                }
        }
 
-       ret = ufshcd_vops_setup_clocks(hba, on);
+       ret = ufshcd_vops_setup_clocks(hba, on, POST_CHANGE);
+       if (ret)
+               return ret;
+
 out:
        if (ret) {
                list_for_each_entry(clki, head, list) {
@@ -5500,8 +5507,6 @@ static void ufshcd_variant_hba_exit(struct ufs_hba *hba)
        if (!hba->vops)
                return;
 
-       ufshcd_vops_setup_clocks(hba, false);
-
        ufshcd_vops_setup_regulators(hba, false);
 
        ufshcd_vops_exit(hba);
@@ -5905,10 +5910,6 @@ disable_clks:
        if (ret)
                goto set_link_active;
 
-       ret = ufshcd_vops_setup_clocks(hba, false);
-       if (ret)
-               goto vops_resume;
-
        if (!ufshcd_is_link_active(hba))
                ufshcd_setup_clocks(hba, false);
        else
@@ -5925,8 +5926,6 @@ disable_clks:
        ufshcd_hba_vreg_set_lpm(hba);
        goto out;
 
-vops_resume:
-       ufshcd_vops_resume(hba, pm_op);
 set_link_active:
        ufshcd_vreg_set_hpm(hba);
        if (ufshcd_is_link_hibern8(hba) && !ufshcd_uic_hibern8_exit(hba))

diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index 430bef11129324a49b131460b9dfa4f0d7b97022..afff7f4de81bbda1cf004c67a3a7d8a5f3b8f233 100644 (file)
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -273,7 +273,8 @@ struct ufs_hba_variant_ops {
        u32     (*get_ufs_hci_version)(struct ufs_hba *);
        int     (*clk_scale_notify)(struct ufs_hba *, bool,
                                    enum ufs_notify_change_status);
-       int     (*setup_clocks)(struct ufs_hba *, bool);
+       int     (*setup_clocks)(struct ufs_hba *, bool,
+                               enum ufs_notify_change_status);
        int     (*setup_regulators)(struct ufs_hba *, bool);
        int     (*hce_enable_notify)(struct ufs_hba *,
                                     enum ufs_notify_change_status);
@@ -755,10 +756,11 @@ static inline int ufshcd_vops_clk_scale_notify(struct ufs_hba *hba,
        return 0;
 }
 
-static inline int ufshcd_vops_setup_clocks(struct ufs_hba *hba, bool on)
+static inline int ufshcd_vops_setup_clocks(struct ufs_hba *hba, bool on,
+                                       enum ufs_notify_change_status status)
 {
        if (hba->vops && hba->vops->setup_clocks)
-               return hba->vops->setup_clocks(hba, on);
+               return hba->vops->setup_clocks(hba, on, status);
        return 0;
 }