soc: fsl: cpm1: qmc: Update TRNSYNC only in transparent mode

commit c3cc3e69b33fee3d276895e0e2d1a8fb37ea5d0e upstream.

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>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Link: https://lore.kernel.org/r/20240808071132.149251-2-herve.codina@bootlin.com
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/soc/fsl/qe/qmc.c b/drivers/soc/fsl/qe/qmc.c
index f498db9abe35f09c9e49cdb0aac306467e7ab37f..04035706b96dc8056231677c9c52fad623b71213 100644 (file)
--- 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;
+               }
        }
 
        /*