[PATCH v2] nvme-apple: Prevent shared tags across queues on Apple A11

[Nick Chan]

On Apple A11, tags of pending commands must be unique across the admin
and IO queues, else the firmware crashes with
"duplicate tag error for tag N", with N being the tag.

Apply the existing workaround for M1 of reserving two tags for the admin
queue to A11.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 04d8ecf37b5e ("nvme: apple: Add Apple A11 support")
Signed-off-by: Nick Chan <towinchenmi@xxxxxxxxx>
---
Changes in v2:
- Complete rewrite to use the existing workaround for M1.
- Link to v1: https://lore.kernel.org/r/20260606-prevent-tag-collision-t8015-v1-0-93ccf4eca550@xxxxxxxxx
---
 drivers/nvme/host/apple.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/drivers/nvme/host/apple.c b/drivers/nvme/host/apple.c
index c692fc73babf..da6e983e2005 100644
--- a/drivers/nvme/host/apple.c
+++ b/drivers/nvme/host/apple.c
@@ -225,7 +225,7 @@ static unsigned int apple_nvme_queue_depth(struct apple_nvme_queue *q)
 {
 	struct apple_nvme *anv = queue_to_apple_nvme(q);
 
-	if (q->is_adminq && anv->hw->has_lsq_nvmmu)
+	if (q->is_adminq)
 		return APPLE_NVME_AQ_DEPTH;
 
 	return anv->hw->max_queue_depth;
@@ -303,7 +303,7 @@ static void apple_nvme_submit_cmd_t8015(struct apple_nvme_queue *q,
 		memcpy((void *)q->sqes + (q->sq_tail << APPLE_NVME_IOSQES),
 			cmd, sizeof(*cmd));
 
-	if (++q->sq_tail == anv->hw->max_queue_depth)
+	if (++q->sq_tail == apple_nvme_queue_depth(q))
 		q->sq_tail = 0;
 
 	writel(q->sq_tail, q->sq_db);
@@ -1139,10 +1139,7 @@ static void apple_nvme_reset_work(struct work_struct *work)
 	}
 
 	/* Setup the admin queue */
-	if (anv->hw->has_lsq_nvmmu)
-		aqa = APPLE_NVME_AQ_DEPTH - 1;
-	else
-		aqa = anv->hw->max_queue_depth - 1;
+	aqa = APPLE_NVME_AQ_DEPTH - 1;
 	aqa |= aqa << 16;
 	writel(aqa, anv->mmio_nvme + NVME_REG_AQA);
 	writeq(anv->adminq.sq_dma_addr, anv->mmio_nvme + NVME_REG_ASQ);
@@ -1325,8 +1322,7 @@ static int apple_nvme_alloc_tagsets(struct apple_nvme *anv)
 	 * both queues. The admin queue gets the first APPLE_NVME_AQ_DEPTH which
 	 * must be marked as reserved in the IO queue.
 	 */
-	if (anv->hw->has_lsq_nvmmu)
-		anv->tagset.reserved_tags = APPLE_NVME_AQ_DEPTH;
+	anv->tagset.reserved_tags = APPLE_NVME_AQ_DEPTH;
 	anv->tagset.queue_depth = anv->hw->max_queue_depth - 1;
 	anv->tagset.timeout = NVME_IO_TIMEOUT;
 	anv->tagset.numa_node = NUMA_NO_NODE;

---
base-commit: e43ffb69e0438cddd72aaa30898b4dc446f664f8
change-id: 20260606-prevent-tag-collision-t8015-1c8adb3234de

Best regards,
-- 
Nick Chan <towinchenmi@xxxxxxxxx>