diff mbox series

[v3,1/2] ufs: core: Add a quirk for handling broken LSDBS field in controller capabilities register

Message ID 20240816-ufs-bug-fix-v3-1-e6fe0e18e2a3@linaro.org (mailing list archive)
State Accepted
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. 16, 2024, 6:25 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 report whether the legacy single
doorbell mode is supported in the controller or not. But some controllers
report '1' in this field which corresponds to 'LSDB not supported', but
they indeed support LSDB. 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      | 8 ++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

Comments

Bart Van Assche Aug. 16, 2024, 5:16 p.m. UTC | #1 
On 8/15/24 11:25 PM, Manivannan Sadhasivam via B4 Relay wrote:
> 'Legacy Queue & Single Doorbell Support (LSDBS)' field in the controller
> capabilities register is supposed to report whether the legacy single
> doorbell mode is supported in the controller or not. But some controllers
> report '1' in this field which corresponds to 'LSDB not supported', but
> they indeed support LSDB. 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.

Reviewed-by: Bart Van Assche <bvanassche@acm.org>
diff mbox series

Patch

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 0b3d0c8e0dda..a6f818cdef0e 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->lsdb_sup = !FIELD_GET(MASK_LSDB_SUPPORT, hba->capabilities);
+	if (!(hba->quirks & UFSHCD_QUIRK_BROKEN_LSDBS_CAP))
+		hba->lsdb_sup = !FIELD_GET(MASK_LSDB_SUPPORT, hba->capabilities);
+	else
+		hba->lsdb_sup = true;
+
 	if (!hba->mcq_sup)
 		return 0;
 
diff --git a/include/ufs/ufshcd.h b/include/ufs/ufshcd.h
index cac0cdb9a916..0fd2aebac728 100644
--- a/include/ufs/ufshcd.h
+++ b/include/ufs/ufshcd.h
@@ -676,6 +676,14 @@  enum ufshcd_quirks {
 	 * the standard best practice for managing keys).
 	 */
 	UFSHCD_QUIRK_KEYS_IN_PRDT			= 1 << 24,
+
+	/*
+	 * This quirk indicates that the controller reports the value 1 (not
+	 * supported) in the Legacy Single DoorBell Support (LSDBS) bit of the
+	 * Controller Capabilities register although it supports the legacy
+	 * single doorbell mode.
+	 */
+	UFSHCD_QUIRK_BROKEN_LSDBS_CAP			= 1 << 25,
 };
 
 enum ufshcd_caps {