Re: [PATCH v2] scsi: ufs: core: Fix bRefClkFreq write failure in HS-LSS mode

Re: [PATCH v2] scsi: ufs: core: Fix bRefClkFreq write failure in HS-LSS mode

[Peter Wang (王信友)]

On Tue, 2026-04-14 at 11:37 +0800, Wang Shuaiwei wrote:
> According to the UFS spec, the bRefClkFreq attribute can only be
> written
> when both sub-links are in LS-MODE. However, in HS LSS mode with
> resetmode = HS_MODE, if the UFS device's default bRefClkFreq value
> differs from the host controller's dev_ref_clk_freq setting, the
> write operation will fail.
> 
> To fix this issue, introduce ufshcd_get_op_mode() function to detect
> the current link operational mode. Call ufshcd_set_dev_ref_clk() only
> when both sub-links are in LS-MODE to ensure the attribute can be
> written successfully.
> 
> Signed-off-by: Wang Shuaiwei <wangshuaiwei1@xiaomi.com>

Reviewed-by: Peter Wang <peter.wang@mediatek.com>

[PATCH v2] scsi: ufs: core: Fix bRefClkFreq write failure in HS-LSS mode

[Wang Shuaiwei]

According to the UFS spec, the bRefClkFreq attribute can only be written
when both sub-links are in LS-MODE. However, in HS LSS mode with
resetmode = HS_MODE, if the UFS device's default bRefClkFreq value
differs from the host controller's dev_ref_clk_freq setting, the
write operation will fail.

To fix this issue, introduce ufshcd_get_op_mode() function to detect
the current link operational mode. Call ufshcd_set_dev_ref_clk() only
when both sub-links are in LS-MODE to ensure the attribute can be
written successfully.

Signed-off-by: Wang Shuaiwei <wangshuaiwei1@xiaomi.com>
---

v1->v2:
- modify the coding style

v1: https://lore.kernel.org/linux-scsi/20260413091126.1219552-1-wangshuaiwei1@xiaomi.com/
---
 drivers/ufs/core/ufshcd.c | 29 +++++++++++++++++++++++++++--
 include/ufs/unipro.h      |  5 +++++
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 9ceb6d6d479d..da38e97a199e 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -9103,6 +9103,30 @@ static void ufshcd_config_mcq(struct ufs_hba *hba)
 		 hba->nutrs);
 }
 
+/**
+ * ufshcd_get_op_mode - get UFS operating mode.
+ * @hba: per-adapter instance
+ *
+ * Use the PA_PWRMODE value to represent the operating mode of UFS.
+ *
+ */
+static enum ufs_op_mode ufshcd_get_op_mode(struct ufs_hba *hba)
+{
+	u32 mode;
+	u8 rx_mode;
+	u8 tx_mode;
+
+	ufshcd_dme_get(hba, UIC_ARG_MIB(PA_PWRMODE), &mode);
+	rx_mode = (mode >> PWRMODE_RX_OFFSET) & PWRMODE_MASK;
+	tx_mode = mode & PWRMODE_MASK;
+
+	if ((rx_mode == SLOW_MODE || rx_mode == SLOWAUTO_MODE) &&
+	    (tx_mode == SLOW_MODE || tx_mode == SLOWAUTO_MODE))
+		return LS_MODE;
+
+	return HS_MODE;
+}
+
 static int ufshcd_post_device_init(struct ufs_hba *hba)
 {
 	int ret;
@@ -9119,11 +9143,12 @@ static int ufshcd_post_device_init(struct ufs_hba *hba)
 		return 0;
 
 	/*
-	 * Set the right value to bRefClkFreq before attempting to
+	 * Set the right value to bRefClkFreq in LS_MODE before attempting to
 	 * switch to HS gears.
 	 */
-	if (hba->dev_ref_clk_freq != REF_CLK_FREQ_INVAL)
+	if (ufshcd_get_op_mode(hba) == LS_MODE && hba->dev_ref_clk_freq != REF_CLK_FREQ_INVAL)
 		ufshcd_set_dev_ref_clk(hba);
+
 	/* Gear up to HS gear. */
 	ret = ufshcd_config_pwr_mode(hba, &hba->max_pwr_info.info);
 	if (ret) {
diff --git a/include/ufs/unipro.h b/include/ufs/unipro.h
index 59de737490ca..3858ed13b2f3 100644
--- a/include/ufs/unipro.h
+++ b/include/ufs/unipro.h
@@ -198,6 +198,11 @@
 #define DME_LocalTC0ReplayTimeOutVal		0xD042
 #define DME_LocalAFC0ReqTimeOutVal		0xD043
 
+enum ufs_op_mode {
+	LS_MODE = 1,
+	HS_MODE = 2,
+};
+
 /* PA power modes */
 enum ufs_pa_pwr_mode {
 	FAST_MODE	= 1,
-- 
2.43.0