linux-kernel - [PATCH v1 3/7] i2c: npcm: Modify timeout evaluation mechanism

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20240807100244.16872-4-kfting@nuvoton.com>
Date: Wed,  7 Aug 2024 18:02:40 +0800
From: warp5tw@...il.com
To: tali.perry@...oton.com,
	Avi.Fishman@...oton.com,
	tomer.maimon@...oton.com,
	avifishman70@...il.com,
	tmaimon77@...il.com,
	tali.perry1@...il.com,
	venture@...gle.com,
	yuenn@...gle.com,
	benjaminfair@...gle.com,
	andi.shyti@...nel.org,
	wsa+renesas@...g-engineering.com,
	rand.sec96@...il.com,
	kwliu@...oton.com,
	jjliu0@...oton.com,
	kfting@...oton.com,
	warp5tw@...il.com
Cc: linux-i2c@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	openbmc@...ts.ozlabs.org
Subject: [PATCH v1 3/7] i2c: npcm: Modify timeout evaluation mechanism

From: Tyrone Ting <kfting@...oton.com>

Increase the timeout and treat it as the total timeout, including retries.
The total timeout is 2 seconds now.

The i2c core layer will have chances to retry to call the i2c driver
transfer function if the i2c driver reports that the bus is busy and
returns EAGAIN.

Fixes: 48acf8292280 ("i2c: Remove redundant comparison in npcm_i2c_reg_slave")
Signed-off-by: Tyrone Ting <kfting@...oton.com>
---
 drivers/i2c/busses/i2c-npcm7xx.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
index bd444ff83a8c..d115ac659900 100644
--- a/drivers/i2c/busses/i2c-npcm7xx.c
+++ b/drivers/i2c/busses/i2c-npcm7xx.c
@@ -2130,19 +2130,12 @@ static int npcm_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
 		}
 	}
 
-	/*
-	 * Adaptive TimeOut: estimated time in usec + 100% margin:
-	 * 2: double the timeout for clock stretching case
-	 * 9: bits per transaction (including the ack/nack)
-	 */
-	timeout_usec = (2 * 9 * USEC_PER_SEC / bus->bus_freq) * (2 + nread + nwrite);
-	timeout = max_t(unsigned long, bus->adap.timeout, usecs_to_jiffies(timeout_usec));
 	if (nwrite >= 32 * 1024 || nread >= 32 * 1024) {
 		dev_err(bus->dev, "i2c%d buffer too big\n", bus->num);
 		return -EINVAL;
 	}
 
-	time_left = jiffies + timeout + 1;
+	time_left = jiffies + bus->adap.timeout / bus->adap.retries + 1;
 	do {
 		/*
 		 * we must clear slave address immediately when the bus is not
@@ -2181,6 +2174,14 @@ static int npcm_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
 	if (npcm_i2c_master_start_xmit(bus, slave_addr, nwrite, nread,
 				       write_data, read_data, read_PEC,
 				       read_block)) {
+		/*
+		 * Adaptive TimeOut: estimated time in usec + 100% margin:
+		 * 2: double the timeout for clock stretching case
+		 * 9: bits per transaction (including the ack/nack)
+		 */
+		timeout_usec = (2 * 9 * USEC_PER_SEC / bus->bus_freq) * (2 + nread + nwrite);
+		timeout = max_t(unsigned long, bus->adap.timeout / bus->adap.retries,
+				usecs_to_jiffies(timeout_usec));
 		time_left = wait_for_completion_timeout(&bus->cmd_complete,
 							timeout);
 
@@ -2306,7 +2307,7 @@ static int npcm_i2c_probe_bus(struct platform_device *pdev)
 	adap = &bus->adap;
 	adap->owner = THIS_MODULE;
 	adap->retries = 3;
-	adap->timeout = msecs_to_jiffies(35);
+	adap->timeout = 2 * HZ;
 	adap->algo = &npcm_i2c_algo;
 	adap->quirks = &npcm_i2c_quirks;
 	adap->algo_data = bus;
-- 
2.34.1