linux-kernel - [PATCH 5.4 341/411] i2c: cadence: Increase timeout per message if necessary

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Message-Id: <20220613094938.937589519@linuxfoundation.org>
Date:   Mon, 13 Jun 2022 12:10:14 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Lucas Tanure <tanureal@...nsource.cirrus.com>,
        Michal Simek <michal.simek@...inx.com>,
        Wolfram Sang <wsa@...nel.org>, Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.4 341/411] i2c: cadence: Increase timeout per message if necessary

From: Lucas Tanure <tanureal@...nsource.cirrus.com>

[ Upstream commit 96789dce043f5bff8b7d62aa28d52a7c59403a84 ]

Timeout as 1 second sets an upper limit on the length
of the transfer executed, but there is no maximum length
of a write or read message set in i2c_adapter_quirks for
this controller.

This upper limit affects devices that require sending
large firmware blobs over I2C.

To remove that limitation, calculate the minimal time
necessary, plus some wiggle room, for every message and
use it instead of the default one second, if more than
one second.

Signed-off-by: Lucas Tanure <tanureal@...nsource.cirrus.com>
Acked-by: Michal Simek <michal.simek@...inx.com>
Signed-off-by: Wolfram Sang <wsa@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/i2c/busses/i2c-cadence.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-cadence.c b/drivers/i2c/busses/i2c-cadence.c
index 17f0dd1f891e..8a3a0991bc1c 100644
--- a/drivers/i2c/busses/i2c-cadence.c
+++ b/drivers/i2c/busses/i2c-cadence.c
@@ -506,7 +506,7 @@ static void cdns_i2c_master_reset(struct i2c_adapter *adap)
 static int cdns_i2c_process_msg(struct cdns_i2c *id, struct i2c_msg *msg,
 		struct i2c_adapter *adap)
 {
-	unsigned long time_left;
+	unsigned long time_left, msg_timeout;
 	u32 reg;
 
 	id->p_msg = msg;
@@ -531,8 +531,16 @@ static int cdns_i2c_process_msg(struct cdns_i2c *id, struct i2c_msg *msg,
 	else
 		cdns_i2c_msend(id);
 
+	/* Minimal time to execute this message */
+	msg_timeout = msecs_to_jiffies((1000 * msg->len * BITS_PER_BYTE) / id->i2c_clk);
+	/* Plus some wiggle room */
+	msg_timeout += msecs_to_jiffies(500);
+
+	if (msg_timeout < adap->timeout)
+		msg_timeout = adap->timeout;
+
 	/* Wait for the signal of completion */
-	time_left = wait_for_completion_timeout(&id->xfer_done, adap->timeout);
+	time_left = wait_for_completion_timeout(&id->xfer_done, msg_timeout);
 	if (time_left == 0) {
 		cdns_i2c_master_reset(adap);
 		dev_err(id->adap.dev.parent,
-- 
2.35.1