This is a note to let you know that I've just added the patch titled can: flexcan: enable RX FIFO after FRZ/HALT valid to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: can-flexcan-enable-rx-fifo-after-frz-halt-valid.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From ec15e27cc8904605846a354bb1f808ea1432f853 Mon Sep 17 00:00:00 2001 From: Joakim Zhang <qiangqing.zhang@xxxxxxx> Date: Thu, 18 Feb 2021 19:00:36 +0800 Subject: can: flexcan: enable RX FIFO after FRZ/HALT valid From: Joakim Zhang <qiangqing.zhang@xxxxxxx> commit ec15e27cc8904605846a354bb1f808ea1432f853 upstream. RX FIFO enable failed could happen when do system reboot stress test: [ 0.303958] flexcan 5a8d0000.can: 5a8d0000.can supply xceiver not found, using dummy regulator [ 0.304281] flexcan 5a8d0000.can (unnamed net_device) (uninitialized): Could not enable RX FIFO, unsupported core [ 0.314640] flexcan 5a8d0000.can: registering netdev failed [ 0.320728] flexcan 5a8e0000.can: 5a8e0000.can supply xceiver not found, using dummy regulator [ 0.320991] flexcan 5a8e0000.can (unnamed net_device) (uninitialized): Could not enable RX FIFO, unsupported core [ 0.331360] flexcan 5a8e0000.can: registering netdev failed [ 0.337444] flexcan 5a8f0000.can: 5a8f0000.can supply xceiver not found, using dummy regulator [ 0.337716] flexcan 5a8f0000.can (unnamed net_device) (uninitialized): Could not enable RX FIFO, unsupported core [ 0.348117] flexcan 5a8f0000.can: registering netdev failed RX FIFO should be enabled after the FRZ/HALT are valid. But the current code enable RX FIFO and FRZ/HALT at the same time. Fixes: e955cead03117 ("CAN: Add Flexcan CAN controller driver") Link: https://lore.kernel.org/r/20210218110037.16591-3-qiangqing.zhang@xxxxxxx Signed-off-by: Joakim Zhang <qiangqing.zhang@xxxxxxx> Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/can/flexcan.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) --- a/drivers/net/can/flexcan.c +++ b/drivers/net/can/flexcan.c @@ -1432,10 +1432,14 @@ static int register_flexcandev(struct ne if (err) goto out_chip_disable; - /* set freeze, halt and activate FIFO, restrict register access */ + /* set freeze, halt */ + err = flexcan_chip_freeze(priv); + if (err) + goto out_chip_disable; + + /* activate FIFO, restrict register access */ reg = priv->read(®s->mcr); - reg |= FLEXCAN_MCR_FRZ | FLEXCAN_MCR_HALT | - FLEXCAN_MCR_FEN | FLEXCAN_MCR_SUPV; + reg |= FLEXCAN_MCR_FEN | FLEXCAN_MCR_SUPV; priv->write(reg, ®s->mcr); /* Currently we only support newer versions of this core Patches currently in stable-queue which might be from qiangqing.zhang@xxxxxxx are queue-5.4/can-flexcan-enable-rx-fifo-after-frz-halt-valid.patch queue-5.4/can-flexcan-assert-frz-bit-in-flexcan_chip_freeze.patch queue-5.4/can-flexcan-invoke-flexcan_chip_freeze-to-enter-freeze-mode.patch