soc: fsl: cpm1: qmc: Handle RPACK initialization

Current code handles the CPM1 version of QMC, RPACK does not need to
be initialized. This is not the case in the QUICC Engine (QE) version.

In preparation of the support for QE, initialize the RPACK register
when the receiver is initialized and each time it is restarted.

This additional RPACK initialization has no impact in the CPM1 version
of QMC.
Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Link: https://lore.kernel.org/r/20240808071132.149251-30-herve.codina@bootlin.comSigned-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>

drivers/soc/fsl/qe/qmc.c

@@ -221,6 +221,7 @@ struct qmc_data {
 	u32 zistate; /* Initial ZISTATE value */
 	u32 zdstate_hdlc; /* Initial ZDSTATE value (HDLC mode) */
 	u32 zdstate_transp; /* Initial ZDSTATE value (Transparent mode) */
+	u32 rpack; /* Initial RPACK value */
 };
 
 struct qmc {
@@ -552,6 +553,7 @@ int qmc_chan_read_submit(struct qmc_chan *chan, dma_addr_t addr, size_t length,
 	/* Restart receiver if needed */
 	if (chan->is_rx_halted && !chan->is_rx_stopped) {
 		/* Restart receiver */
+		qmc_write32(chan->s_param + QMC_SPE_RPACK, chan->qmc->data->rpack);
 		qmc_write32(chan->s_param + QMC_SPE_ZDSTATE,
 			    chan->mode == QMC_TRANSPARENT ?
 				chan->qmc->data->zdstate_transp :
@@ -980,6 +982,7 @@ static int qmc_chan_start_rx(struct qmc_chan *chan)
 	}
 
 	/* Restart the receiver */
+	qmc_write32(chan->s_param + QMC_SPE_RPACK, chan->qmc->data->rpack);
 	qmc_write32(chan->s_param + QMC_SPE_ZDSTATE,
 		    chan->mode == QMC_TRANSPARENT ?
 			chan->qmc->data->zdstate_transp :
@@ -1405,6 +1408,7 @@ static int qmc_setup_chan(struct qmc *qmc, struct qmc_chan *chan)
 	qmc_write32(chan->s_param + QMC_SPE_TSTATE, chan->qmc->data->tstate);
 	qmc_write32(chan->s_param + QMC_SPE_RSTATE, chan->qmc->data->rstate);
 	qmc_write32(chan->s_param + QMC_SPE_ZISTATE, chan->qmc->data->zistate);
+	qmc_write32(chan->s_param + QMC_SPE_RPACK, chan->qmc->data->rpack);
 	if (chan->mode == QMC_TRANSPARENT) {
 		qmc_write32(chan->s_param + QMC_SPE_ZDSTATE, chan->qmc->data->zdstate_transp);
 		qmc_write16(chan->s_param + QMC_SPE_TMRBLR, 60);
@@ -1544,6 +1548,8 @@ static void qmc_irq_gint(struct qmc *qmc)
 			/* Restart the receiver if needed */
 			spin_lock_irqsave(&chan->rx_lock, flags);
 			if (chan->rx_pending && !chan->is_rx_stopped) {
+				qmc_write32(chan->s_param + QMC_SPE_RPACK,
+					    chan->qmc->data->rpack);
 				qmc_write32(chan->s_param + QMC_SPE_ZDSTATE,
 					    chan->mode == QMC_TRANSPARENT ?
 						chan->qmc->data->zdstate_transp :
@@ -1810,6 +1816,7 @@ static const struct qmc_data qmc_data_cpm1 = {
 	.zistate = 0x00000100,
 	.zdstate_hdlc = 0x00000080,
 	.zdstate_transp = 0x18000080,
+	.rpack = 0x00000000,
 };
 
 static const struct of_device_id qmc_id_table[] = {