[PATCH] tcan4x5x: clear MRAM before entering Normal mode

[PATCH] tcan4x5x: clear MRAM before entering Normal mode

[Torin Cooper-Bennun]

This prevents a potentially destructive race condition. The device is
fully operational on the bus after entering Normal mode, so zeroing the
MRAM after entering this mode may lead to loss of information, e.g. new
received messages.

Signed-off-by: Torin Cooper-Bennun <torin@maxiluxsystems.com>
---
 drivers/net/can/m_can/tcan4x5x-core.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/can/m_can/tcan4x5x-core.c b/drivers/net/can/m_can/tcan4x5x-core.c
index b7caec769ddb..4147cecfbbd6 100644
--- a/drivers/net/can/m_can/tcan4x5x-core.c
+++ b/drivers/net/can/m_can/tcan4x5x-core.c
@@ -237,14 +237,14 @@ static int tcan4x5x_init(struct m_can_classdev *cdev)
 	if (ret)
 		return ret;
 
+	/* Zero out the MCAN buffers */
+	m_can_init_ram(cdev);
+
 	ret = regmap_update_bits(tcan4x5x->regmap, TCAN4X5X_CONFIG,
 				 TCAN4X5X_MODE_SEL_MASK, TCAN4X5X_MODE_NORMAL);
 	if (ret)
 		return ret;
 
-	/* Zero out the MCAN buffers */
-	m_can_init_ram(cdev);
-
 	return ret;
 }
 
-- 
2.30.0

Re: [PATCH] tcan4x5x: clear MRAM before entering Normal mode

[Marc Kleine-Budde]

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On 26.02.2021 16:34:41, Torin Cooper-Bennun wrote:
> This prevents a potentially destructive race condition. The device is
> fully operational on the bus after entering Normal mode, so zeroing the
> MRAM after entering this mode may lead to loss of information, e.g. new
> received messages.
> 
> Signed-off-by: Torin Cooper-Bennun <torin@maxiluxsystems.com>

I've added a Fixed: tag and applied the patch to linux-can/testing.

Thanks,
Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde           |
Embedded Linux                   | https://www.pengutronix.de  |
Vertretung West/Dortmund         | Phone: +49-231-2826-924     |
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