linux-kernel - [PATCH] mmc: dw_mmc: avoid long timeout if register invalid

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Date:   Fri, 17 Sep 2021 07:50:44 +0000
From:   Christian Löhle <CLoehle@...erstone.com>
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-mmc@...r.kernel.org" <linux-mmc@...r.kernel.org>
CC:     "marten.lindahl@...s.com" <marten.lindahl@...s.com>,
        "jh80.chung@...sung.com" <jh80.chung@...sung.com>,
        "ulf.hansson@...aro.org" <ulf.hansson@...aro.org>
Subject: [PATCH] mmc: dw_mmc: avoid long timeout if register invalid


Set the limit to 1s if the register is at reset value.

Signed-off-by: Christian Loehle <cloehle@...erstone.com>
---
 drivers/mmc/host/dw_mmc.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 6578cc64ae9e..cd9a6e0a7449 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -1983,6 +1983,14 @@ static void dw_mci_set_drto(struct dw_mci *host)
 	/* add a bit spare time */
 	drto_ms += 10;
 
+	/*
+	 * If TMOUT register still holds the reset value the above calculation
+	 * would yield a timeout of over 167 seconds, limit it to 1000ms.
+	 * Normal reads/writes should not take anywhere close to 120s.
+	 */
+	if (drto_ms > 120000)
+		drto_ms = 1000;
+
 	spin_lock_irqsave(&host->irq_lock, irqflags);
 	if (!test_bit(EVENT_DATA_COMPLETE, &host->pending_events))
 		mod_timer(&host->dto_timer,
-- 
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