FAILED: patch "[PATCH] i3c: mipi-i3c-hci: Correct RING_CTRL_ABORT handling in DMA" failed to apply to 6.6-stable tree

The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x b795e68bf3073d67bebbb5a44d93f49efc5b8cc7
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026031741-express-sphinx-b65d@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From b795e68bf3073d67bebbb5a44d93f49efc5b8cc7 Mon Sep 17 00:00:00 2001
From: Adrian Hunter <[email protected]>
Date: Fri, 6 Mar 2026 09:24:45 +0200
Subject: [PATCH] i3c: mipi-i3c-hci: Correct RING_CTRL_ABORT handling in DMA
dequeue

The logic used to abort the DMA ring contains several flaws:

1. The driver unconditionally issues a ring abort even when the ring has already stopped.
2. The completion used to wait for abort completion is never re-initialized, resulting in incorrect wait behavior.
3. The abort sequence unintentionally clears RING_CTRL_ENABLE, which resets hardware ring pointers and disrupts the controller state.
4. If the ring is already stopped, the abort operation should be considered successful without attempting further action.

Fix the abort handling by checking whether the ring is running before issuing an abort, re-initializing the completion when needed, ensuring that RING_CTRL_ENABLE remains asserted during abort, and treating an already stopped ring as a successful condition.

index d7840ff69e59..a3e8e01a35c9 100644
@@ -546,18 +546,25 @@ static bool hci_dma_dequeue_xfer(struct i3c_hci *hci,
 	struct hci_rh_data *rh = &rings->headers[xfer_list[0].ring_number];
 	unsigned int i;
 	bool did_unqueue = false;
+	u32 ring_status;
 
 	guard(mutex)(&hci->control_mutex);
 
-	/* stop the ring */
-	rh_reg_write(RING_CONTROL, RING_CTRL_ABORT);
-	if (wait_for_completion_timeout(&rh->op_done, HZ) == 0) {
-		/*
-		 * We're deep in it if ever this condition is ever met.
-		 * Hardware might still be writing to memory, etc.
-		 */
-		dev_crit(&hci->master.dev, "unable to abort the ring\n");
-		WARN_ON(1);
+	ring_status = rh_reg_read(RING_STATUS);
+	if (ring_status & RING_STATUS_RUNNING) {
+		/* stop the ring */
+		reinit_completion(&rh->op_done);
+		rh_reg_write(RING_CONTROL, RING_CTRL_ENABLE | RING_CTRL_ABORT);
+		wait_for_completion_timeout(&rh->op_done, HZ);
+		ring_status = rh_reg_read(RING_STATUS);
+		if (ring_status & RING_STATUS_RUNNING) {
+			/*
+			 * We're deep in it if ever this condition is ever met.
+			 * Hardware might still be writing to memory, etc.
+			 */
+			dev_crit(&hci->master.dev, "unable to abort the ring\n");
+			WARN_ON(1);
+		}
 	}
 
 	spin_lock_irq(&hci->lock);