The TRNSYNC feature is available (and enabled) only in transparent mode.

Since commit 7cc9bda9c163 ("soc: fsl: cpm1: qmc: Handle timeslot entries at channel start() and stop()") TRNSYNC register is updated in transparent and hdlc mode. In hdlc mode, the address of the TRNSYNC register is used by the QMC for other internal purpose. Even if no weird results were observed in hdlc mode, touching this register in this mode is wrong.

Update TRNSYNC only in transparent mode.

Fixes: 7cc9bda9c163 ("soc: fsl: cpm1: qmc: Handle timeslot entries at channel start() and stop()") Cc: stable@vger.kernel.org Signed-off-by: Herve Codina herve.codina@bootlin.com --- drivers/soc/fsl/qe/qmc.c | 24 ++++++++++++++---------- 1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/drivers/soc/fsl/qe/qmc.c b/drivers/soc/fsl/qe/qmc.c index 76bb496305a0..bacabf731dcb 100644 --- a/drivers/soc/fsl/qe/qmc.c +++ b/drivers/soc/fsl/qe/qmc.c @@ -940,11 +940,13 @@ static int qmc_chan_start_rx(struct qmc_chan *chan) goto end; }

- ret = qmc_setup_chan_trnsync(chan->qmc, chan); - if (ret) { - dev_err(chan->qmc->dev, "chan %u: setup TRNSYNC failed (%d)\n", - chan->id, ret); - goto end; + if (chan->mode == QMC_TRANSPARENT) { + ret = qmc_setup_chan_trnsync(chan->qmc, chan); + if (ret) { + dev_err(chan->qmc->dev, "chan %u: setup TRNSYNC failed (%d)\n", + chan->id, ret); + goto end; + } }

/* Restart the receiver */ @@ -982,11 +984,13 @@ static int qmc_chan_start_tx(struct qmc_chan *chan) goto end; }

- ret = qmc_setup_chan_trnsync(chan->qmc, chan); - if (ret) { - dev_err(chan->qmc->dev, "chan %u: setup TRNSYNC failed (%d)\n", - chan->id, ret); - goto end; + if (chan->mode == QMC_TRANSPARENT) { + ret = qmc_setup_chan_trnsync(chan->qmc, chan); + if (ret) { + dev_err(chan->qmc->dev, "chan %u: setup TRNSYNC failed (%d)\n", + chan->id, ret); + goto end; + } }

/*