queue-6.1/i3c-master-svc-prevent-incomplete-ibi-transaction.patch

From a6188cbe73c1a734c3f29a755fcdf082f6f27421 Mon Sep 17 00:00:00 2001
From: Sasha Levin <sashal@kernel.org>
Date: Mon, 27 Oct 2025 11:47:15 +0800
Subject: i3c: master: svc: Prevent incomplete IBI transaction

From: Stanley Chu <yschu@nuvoton.com>

[ Upstream commit 3a36273e5a07dda0ccec193800f3b78c3c0380af ]

If no free IBI slot is available, svc_i3c_master_handle_ibi returns
immediately. This causes the STOP condition to be missed because the
EmitStop request is sent when the transfer is not complete. To resolve
this, svc_i3c_master_handle_ibi must wait for the transfer to complete
before returning.

Fixes: dd3c52846d59 ("i3c: master: svc: Add Silvaco I3C master driver")
Signed-off-by: Stanley Chu <yschu@nuvoton.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://patch.msgid.link/20251027034715.708243-1-yschu@nuvoton.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/i3c/master/svc-i3c-master.c | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c
index fda472d84549b..21ea4166057d8 100644
--- a/drivers/i3c/master/svc-i3c-master.c
+++ b/drivers/i3c/master/svc-i3c-master.c
@@ -350,21 +350,27 @@ static int svc_i3c_master_handle_ibi(struct svc_i3c_master *master,
 	int ret, val;
 	u8 *buf;
 
-	slot = i3c_generic_ibi_get_free_slot(data->ibi_pool);
-	if (!slot)
-		return -ENOSPC;
-
-	slot->len = 0;
-	buf = slot->data;
-
+	/*
+	 * Wait for transfer to complete before returning. Otherwise, the EmitStop
+	 * request might be sent when the transfer is not complete.
+	 */
 	ret = readl_relaxed_poll_timeout(master->regs + SVC_I3C_MSTATUS, val,
 						SVC_I3C_MSTATUS_COMPLETE(val), 0, 1000);
 	if (ret) {
 		dev_err(master->dev, "Timeout when polling for COMPLETE\n");
-		i3c_generic_ibi_recycle_slot(data->ibi_pool, slot);
 		return ret;
 	}
 
+	slot = i3c_generic_ibi_get_free_slot(data->ibi_pool);
+	if (!slot) {
+		dev_dbg(master->dev, "No free ibi slot, drop the data\n");
+		writel(SVC_I3C_MDATACTRL_FLUSHRB, master->regs + SVC_I3C_MDATACTRL);
+		return -ENOSPC;
+	}
+
+	slot->len = 0;
+	buf = slot->data;
+
 	while (SVC_I3C_MSTATUS_RXPEND(readl(master->regs + SVC_I3C_MSTATUS))  &&
 	       slot->len < SVC_I3C_FIFO_SIZE) {
 		mdatactrl = readl(master->regs + SVC_I3C_MDATACTRL);
-- 
2.51.0