Linux 4.19.51

[thirdparty/kernel/stable-queue.git] / releases / 4.19.51 / mmc-mmci-prevent-polling-for-busy-detection-in-irq-c.patch

From fa04a59ef7e1378f96e374774f381523d96c92a4 Mon Sep 17 00:00:00 2001
From: Ludovic Barre <ludovic.barre@st.com>
Date: Fri, 26 Apr 2019 09:46:35 +0200
Subject: mmc: mmci: Prevent polling for busy detection in IRQ context

[ Upstream commit 8520ce1e17799b220ff421d4f39438c9c572ade3 ]

The IRQ handler, mmci_irq(), loops until all status bits have been cleared.
However, the status bit signaling busy in variant->busy_detect_flag, may be
set even if busy detection isn't monitored for the current request.

This may be the case for the CMD11 when switching the I/O voltage, which
leads to that mmci_irq() busy loops in IRQ context. Fix this problem, by
clearing the status bit for busy, before continuing to validate the
condition for the loop. This is safe, because the busy status detection has
already been taken care of by mmci_cmd_irq().

Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/mmc/host/mmci.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index 1841d250e9e2..eb1a65cb878f 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -1295,9 +1295,10 @@ static irqreturn_t mmci_irq(int irq, void *dev_id)
 		}
 
 		/*
-		 * Don't poll for busy completion in irq context.
+		 * Busy detection has been handled by mmci_cmd_irq() above.
+		 * Clear the status bit to prevent polling in IRQ context.
 		 */
-		if (host->variant->busy_detect && host->busy_status)
+		if (host->variant->busy_detect_flag)
 			status &= ~host->variant->busy_detect_flag;
 
 		ret = 1;
-- 
2.20.1