6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Matthias Schiffer matthias.schiffer@ew.tq-group.com
[ Upstream commit fca2977629f49dee437e217c3fc423b6e0cad98c ]
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: cd5a46ce6fa6 ("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... Signed-off-by: Marc Kleine-Budde mkl@pengutronix.de Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/can/m_can/m_can.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c index 533bcb77c9f9..67c404fbe166 100644 --- a/drivers/net/can/m_can/m_can.c +++ b/drivers/net/can/m_can/m_can.c @@ -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)