linux-kernel - [PATCH 3.16 160/202] i2c: cadence: Fix the hold bit setting

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: <lsq.1556377989.422165519@decadent.org.uk>
Date:   Sat, 27 Apr 2019 16:13:09 +0100
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, Denis Kirjanov <kda@...ux-powerpc.org>,
        "Michal Simek" <michal.simek@...inx.com>,
        "Wolfram Sang" <wsa@...-dreams.de>,
        "Kyle Roeschley" <kyle.roeschley@...com>,
        "Shubhrajyoti Datta" <shubhrajyoti.datta@...inx.com>
Subject: [PATCH 3.16 160/202] i2c: cadence: Fix the hold bit setting

3.16.66-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Shubhrajyoti Datta <shubhrajyoti.datta@...inx.com>

commit d358def706880defa4c9e87381c5bf086a97d5f9 upstream.

In case the hold bit is not needed we are carrying the old values.
Fix the same by resetting the bit when not needed.

Fixes the sporadic i2c bus lockups on National Instruments
Zynq-based devices.

Fixes: df8eb5691c48 ("i2c: Add driver for Cadence I2C controller")
Reported-by: Kyle Roeschley <kyle.roeschley@...com>
Acked-by: Michal Simek <michal.simek@...inx.com>
Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@...inx.com>
Tested-by: Kyle Roeschley <kyle.roeschley@...com>
Signed-off-by: Wolfram Sang <wsa@...-dreams.de>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 drivers/i2c/busses/i2c-cadence.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

--- a/drivers/i2c/busses/i2c-cadence.c
+++ b/drivers/i2c/busses/i2c-cadence.c
@@ -320,8 +320,10 @@ static void cdns_i2c_mrecv(struct cdns_i
 	 * Check for the message size against FIFO depth and set the
 	 * 'hold bus' bit if it is greater than FIFO depth.
 	 */
-	if (id->recv_count > CDNS_I2C_FIFO_DEPTH)
+	if ((id->recv_count > CDNS_I2C_FIFO_DEPTH)  || id->bus_hold_flag)
 		ctrl_reg |= CDNS_I2C_CR_HOLD;
+	else
+		ctrl_reg = ctrl_reg & ~CDNS_I2C_CR_HOLD;
 
 	cdns_i2c_writereg(ctrl_reg, CDNS_I2C_CR_OFFSET);
 
@@ -375,8 +377,11 @@ static void cdns_i2c_msend(struct cdns_i
 	 * Check for the message size against FIFO depth and set the
 	 * 'hold bus' bit if it is greater than FIFO depth.
 	 */
-	if (id->send_count > CDNS_I2C_FIFO_DEPTH)
+	if ((id->send_count > CDNS_I2C_FIFO_DEPTH) || id->bus_hold_flag)
 		ctrl_reg |= CDNS_I2C_CR_HOLD;
+	else
+		ctrl_reg = ctrl_reg & ~CDNS_I2C_CR_HOLD;
+
 	cdns_i2c_writereg(ctrl_reg, CDNS_I2C_CR_OFFSET);
 
 	/* Clear the interrupts in interrupt status register. */