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[net,6/6] can: tcan4x5x: tcan4x5x_init(): fix initialization - clear MRAM before entering Normal Mode

Message ID 20210301112100.197939-7-mkl@pengutronix.de (mailing list archive)
State Accepted
Delegated to: Netdev Maintainers
Headers show
Series [net,1/6] can: flexcan: assert FRZ bit in flexcan_chip_freeze() | expand

Checks

Context Check Description
netdev/cover_letter success Pull request
netdev/fixes_present success Link
netdev/patch_count success Link
netdev/tree_selection success Clearly marked for net
netdev/subject_prefix success Link
netdev/cc_maintainers fail 2 blamed authors not CCed: wg@grandegger.com dmurphy@ti.com; 2 maintainers not CCed: wg@grandegger.com dmurphy@ti.com
netdev/source_inline success Was 0 now: 0
netdev/verify_signedoff success Link
netdev/module_param success Was 0 now: 0
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/verify_fixes success Link
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 17 lines checked
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/header_inline success Link
netdev/stable success Stable not CCed

Commit Message

Marc Kleine-Budde March 1, 2021, 11:21 a.m. UTC 
From: Torin Cooper-Bennun <torin@maxiluxsystems.com>

This patch 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.

This patch fixes the problem by first initializing the MRAM, then
bringing the device into Normale Mode.

Fixes: 5443c226ba91 ("can: tcan4x5x: Add tcan4x5x driver to the kernel")
Link: https://lore.kernel.org/r/20210226163440.313628-1-torin@maxiluxsystems.com
Suggested-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Torin Cooper-Bennun <torin@maxiluxsystems.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 drivers/net/can/m_can/tcan4x5x-core.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
diff mbox series

Patch

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;
 }