From 1e879e8fa9f62e18d79bfc339050bf8fed7a81e4 Mon Sep 17 00:00:00 2001 From: Subhash Jadavani Date: Thu, 6 Oct 2016 21:48:22 -0700 Subject: [PATCH] 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 Reviewed-by: Kiwoong Kim Signed-off-by: Martin K. Petersen --- drivers/scsi/ufs/ufs-qcom.c | 10 ++++++---- drivers/scsi/ufs/ufshcd.c | 17 ++++++++--------- drivers/scsi/ufs/ufshcd.h | 8 +++++--- 3 files changed, 19 insertions(+), 16 deletions(-) diff --git a/drivers/scsi/ufs/ufs-qcom.c b/drivers/scsi/ufs/ufs-qcom.c index 3aedf73f1131..3c4f602eecd2 100644 --- 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 05c745663c10..571a2f64a01d 100644 --- 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 430bef111293..afff7f4de81b 100644 --- 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; } -- 2.20.1