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can: m_can: set init flag earlier in probe

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[ Upstream commit fca2977629 ]

While an m_can controller usually already has the init flag from a
hardware reset, no such reset happens on the integrated m_can_pci of the
Intel Elkhart Lake. If the CAN controller is found in an active state,
m_can_dev_setup() would fail because m_can_niso_supported() calls
m_can_cccr_update_bits(), which refuses to modify any other configuration
bits when CCCR_INIT is not set.

To avoid this issue, set CCCR_INIT before attempting to modify any other
configuration flags.

Fixes: cd5a46ce6f ("can: m_can: don't enable transceiver when probing")
Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Reviewed-by: Markus Schneider-Pargmann <msp@baylibre.com>
Link: https://patch.msgid.link/e247f331cb72829fcbdfda74f31a59cbad1a6006.1728288535.git.matthias.schiffer@ew.tq-group.com
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Matthias Schiffer
2024-10-07 10:23:58 +02:00
committed by Greg Kroah-Hartman
parent 5c553262f0
commit 3a3696ec46
1 changed files with 9 additions and 5 deletions
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drivers/net/can/m_can/m_can.c
+9 -5
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@@ -1695,6 +1695,14 @@ static int m_can_dev_setup(struct m_can_classdev *cdev)
return -EINVAL;
}
/* Write the INIT bit, in case no hardware reset has happened before
* the probe (for example, it was observed that the Intel Elkhart Lake
* SoCs do not properly reset the CAN controllers on reboot)
*/
err = m_can_cccr_update_bits(cdev, CCCR_INIT, CCCR_INIT);
if (err)
return err;
if (!cdev->is_peripheral)
netif_napi_add(dev, &cdev->napi, m_can_poll);
@@ -1746,11 +1754,7 @@ static int m_can_dev_setup(struct m_can_classdev *cdev)
return -EINVAL;
}
/* Forcing standby mode should be redundant, as the chip should be in
* standby after a reset. Write the INIT bit anyways, should the chip
* be configured by previous stage.
*/
return m_can_cccr_update_bits(cdev, CCCR_INIT, CCCR_INIT);
return 0;
}
static void m_can_stop(struct net_device *dev)