scsi: ufs: core: Expand MCQ queue slot to DeviceQueueDepth + 1

[ Upstream commit defde5a50d91c74e1ce71a7f0bce7fb1ae311d84 ]

The UFSHCI 4.0 specification mandates that there should always be at least
one empty slot in each queue for distinguishing between full and empty
states. Enlarge 'hwq->max_entries' to 'DeviceQueueDepth + 1' to allow
UFSHCI 4.0 controllers to fully utilize MCQ queue slots.

Fixes: 4682abfae2eb ("scsi: ufs: core: mcq: Allocate memory for MCQ mode")
Signed-off-by: Naomi Chu <naomi.chu@mediatek.com>
Link: https://lore.kernel.org/r/20231102052426.12006-2-naomi.chu@mediatek.com
Reviewed-by: Stanley Chu <stanley.chu@mediatek.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Peter Wang <peter.wang@mediatek.com>
Reviewed-by: Chun-Hung <chun-hung.wu@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/ufs/core/ufs-mcq.c b/drivers/ufs/core/ufs-mcq.c
index 2ba8ec2..5c75ab9 100644 (file)
--- a/drivers/ufs/core/ufs-mcq.c
+++ b/drivers/ufs/core/ufs-mcq.c
@@ -436,7 +436,7 @@ int ufshcd_mcq_init(struct ufs_hba *hba)
 
        for (i = 0; i < hba->nr_hw_queues; i++) {
                hwq = &hba->uhq[i];
-               hwq->max_entries = hba->nutrs;
+               hwq->max_entries = hba->nutrs + 1;
                spin_lock_init(&hwq->sq_lock);
                spin_lock_init(&hwq->cq_lock);
                mutex_init(&hwq->sq_mutex);