From: Palash Kambar <palash.kambar@oss.qualcomm.com>

On platforms that support Auto Hibern8 (AH8), the UFS controller can
autonomously de-assert clk_req signals to the GCC when entering the
Hibern8 state. This allows GCC to gate unused clocks, improving
power efficiency.

Enable the Clock Request feature by setting the UFS_HW_CLK_CTRL_EN
bit in the UFS_AH8_CFG register, as recommended in the Hardware
Programming Guidelines.

Signed-off-by: Palash Kambar <palash.kambar@oss.qualcomm.com>
---
 drivers/ufs/host/ufs-qcom.c | 11 +++++++++++
 drivers/ufs/host/ufs-qcom.h | 11 +++++++++++
 2 files changed, 22 insertions(+)

diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
index 8ebee0cc5313..0e653b34b00d 100644
--- a/drivers/ufs/host/ufs-qcom.c
+++ b/drivers/ufs/host/ufs-qcom.c
@@ -683,6 +683,14 @@ static int ufs_qcom_cfg_timers(struct ufs_hba *hba, bool is_pre_scale_up, unsign
 	return 0;
 }
 
+static void ufs_qcom_link_startup_post_change(struct ufs_hba *hba)
+{
+	if (ufshcd_is_auto_hibern8_supported(hba)) {
+		ufshcd_rmwl(hba, UFS_HW_CLK_CTRL_EN, UFS_HW_CLK_CTRL_EN,
+			    UFS_AH8_CFG);
+	}
+}
+
 static int ufs_qcom_link_startup_notify(struct ufs_hba *hba,
 					enum ufs_notify_change_status status)
 {
@@ -708,6 +716,9 @@ static int ufs_qcom_link_startup_notify(struct ufs_hba *hba,
 		 */
 		err = ufshcd_disable_host_tx_lcc(hba);
 
+		break;
+	case POST_CHANGE:
+		ufs_qcom_link_startup_post_change(hba);
 		break;
 	default:
 		break;
diff --git a/drivers/ufs/host/ufs-qcom.h b/drivers/ufs/host/ufs-qcom.h
index 380d02333d38..f19def37c86f 100644
--- a/drivers/ufs/host/ufs-qcom.h
+++ b/drivers/ufs/host/ufs-qcom.h
@@ -228,6 +228,17 @@ enum {
  */
 #define NUM_TX_R1W1 13
 
+/* bit definitions for UFS_AH8_CFG register */
+#define CC_UFS_SYS_CLK_REQ_EN          BIT(2)
+#define CC_UFS_ICE_CORE_CLK_REQ_EN     BIT(3)
+#define CC_UFS_UNIPRO_CORE_CLK_REQ_EN  BIT(4)
+#define CC_UFS_AUXCLK_REQ_EN           BIT(5)
+
+#define UFS_HW_CLK_CTRL_EN	(CC_UFS_SYS_CLK_REQ_EN |\
+				CC_UFS_ICE_CORE_CLK_REQ_EN |\
+				CC_UFS_UNIPRO_CORE_CLK_REQ_EN |\
+				CC_UFS_AUXCLK_REQ_EN)
+
 static inline void
 ufs_qcom_get_controller_revision(struct ufs_hba *hba,
 				 u8 *major, u16 *minor, u16 *step)
-- 
2.34.1

On 3/27/26 2:03 AM, palash.kambar@oss.qualcomm.com wrote:
> On platforms that support Auto Hibern8 (AH8), the UFS controller can
> autonomously de-assert clk_req signals to the GCC when entering the
> Hibern8 state. This allows GCC to gate unused clocks, improving
> power efficiency.

What is the "GCC"? Please expand acronyms that are neither defined in
the UFSHCI standard nor in the UFS standard.

> +static void ufs_qcom_link_startup_post_change(struct ufs_hba *hba)
> +{
> +	if (ufshcd_is_auto_hibern8_supported(hba)) {
> +		ufshcd_rmwl(hba, UFS_HW_CLK_CTRL_EN, UFS_HW_CLK_CTRL_EN,
> +			    UFS_AH8_CFG);
> +	}
> +}

 From the Linux kernel coding style "Do not unnecessarily use braces 
where a single statement will do." Please follow that rule.

Thanks,

Bart.