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[v2,2/3] ufs: core: Add a quirk for handling broken LSDBS field in controller capabilities register

Message ID 20240815-ufs-bug-fix-v2-2-b373afae888f@linaro.org
State New
Headers show
Series ufs: qcom: Fix probe failure on SM8550 SoC due to broken LSDBS field | expand

Commit Message

Manivannan Sadhasivam via B4 Relay Aug. 15, 2024, 5:16 a.m. UTC 
From: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

'Legacy Queue & Single Doorbell Support (LSDBS)' field in the controller
capabilities register is supposed to be reserved for UFSHCI 3.0 based
controllers and should read as 0. But some controllers may report bogus
value of 1 due to the hardware bug. So let's add a quirk to handle those
controllers.

If the quirk is enabled by the controller driver, then LSDBS register field
will be ignored and legacy/single doorbell mode is assumed to be enabled
always.

Tested-by: Amit Pundir <amit.pundir@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
---
 drivers/ufs/core/ufshcd.c | 6 +++++-
 include/ufs/ufshcd.h      | 7 +++++++
 2 files changed, 12 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 0b1787074215..8c9ff8696bcd 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -2426,7 +2426,11 @@  static inline int ufshcd_hba_capabilities(struct ufs_hba *hba)
 	 * 0h: legacy single doorbell support is available
 	 * 1h: indicate that legacy single doorbell support has been removed
 	 */
-	hba->lsdbs_sup = !FIELD_GET(MASK_LSDBS_SUPPORT, hba->capabilities);
+	if (!(hba->quirks & UFSHCD_QUIRK_BROKEN_LSDBS_CAP))
+		hba->lsdbs_sup = !FIELD_GET(MASK_LSDBS_SUPPORT, hba->capabilities);
+	else
+		hba->lsdbs_sup = true;
+
 	if (!hba->mcq_sup)
 		return 0;
 
diff --git a/include/ufs/ufshcd.h b/include/ufs/ufshcd.h
index c6ab1c671ad7..250adb6eddb6 100644
--- a/include/ufs/ufshcd.h
+++ b/include/ufs/ufshcd.h
@@ -676,6 +676,13 @@  enum ufshcd_quirks {
 	 * the standard best practice for managing keys).
 	 */
 	UFSHCD_QUIRK_KEYS_IN_PRDT			= 1 << 24,
+
+	/*
+	 * This quirk needs to be enabled if the host controller has the broken
+	 * Legacy Queue & Single Doorbell Support (LSDBS) field in Controller
+	 * Capabilities register.
+	 */
+	UFSHCD_QUIRK_BROKEN_LSDBS_CAP			= 1 << 25,
 };
 
 enum ufshcd_caps {