soc: fsl: cpm1: qmc: Re-order probe() operations

Current code handles CPM1 version of QMC. In the QUICC Engine (QE)
version, some operations done at probe() need to be done in a different
order.

In order to prepare the support for the QE version, changed the sequence
of operation done at probe():
- Retrieve the tsa_serial earlier, before initializing resources.
- Group SCC initialisation and do this initialization when it is really
  needed in the probe() sequence.

Having the QE compatible sequence in the CPM1 version does not lead to
any issue and works correctly without any regressions.
Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Link: https://lore.kernel.org/r/20240808071132.149251-26-herve.codina@bootlin.comSigned-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>

drivers/soc/fsl/qe/qmc.c

@@ -1614,6 +1614,12 @@ static int qmc_probe(struct platform_device *pdev)
 	}
 	INIT_LIST_HEAD(&qmc->chan_head);
 
+	qmc->tsa_serial = devm_tsa_serial_get_byphandle(qmc->dev, np, "fsl,tsa-serial");
+	if (IS_ERR(qmc->tsa_serial)) {
+		return dev_err_probe(qmc->dev, PTR_ERR(qmc->tsa_serial),
+				     "Failed to get TSA serial\n");
+	}
+
 	qmc->scc_regs = devm_platform_ioremap_resource_byname(pdev, "scc_regs");
 	if (IS_ERR(qmc->scc_regs))
 		return PTR_ERR(qmc->scc_regs);
@@ -1630,33 +1636,13 @@ static int qmc_probe(struct platform_device *pdev)
 	if (IS_ERR(qmc->dpram))
 		return PTR_ERR(qmc->dpram);
 
-	qmc->tsa_serial = devm_tsa_serial_get_byphandle(qmc->dev, np, "fsl,tsa-serial");
-	if (IS_ERR(qmc->tsa_serial)) {
-		return dev_err_probe(qmc->dev, PTR_ERR(qmc->tsa_serial),
-				     "Failed to get TSA serial\n");
-	}
-
-	/* Connect the serial (SCC) to TSA */
-	ret = tsa_serial_connect(qmc->tsa_serial);
-	if (ret) {
-		dev_err(qmc->dev, "Failed to connect TSA serial\n");
-		return ret;
-	}
-
 	/* Parse channels informationss */
 	ret = qmc_of_parse_chans(qmc, np);
 	if (ret)
-		goto err_tsa_serial_disconnect;
+		return ret;
 
 	nb_chans = qmc_nb_chans(qmc);
 
-	/* Init GMSR_H and GMSR_L registers */
-	qmc_write32(qmc->scc_regs + SCC_GSMRH,
-		    SCC_GSMRH_CDS | SCC_GSMRH_CTSS | SCC_GSMRH_CDP | SCC_GSMRH_CTSP);
-
-	/* enable QMC mode */
-	qmc_write32(qmc->scc_regs + SCC_GSMRL, SCC_GSMRL_MODE_QMC);
-
 	/*
 	 * Allocate the buffer descriptor table
 	 * 8 rx and 8 tx descriptors per channel
@@ -1666,8 +1652,7 @@ static int qmc_probe(struct platform_device *pdev)
 					    &qmc->bd_dma_addr, GFP_KERNEL);
 	if (!qmc->bd_table) {
 		dev_err(qmc->dev, "Failed to allocate bd table\n");
-		ret = -ENOMEM;
-		goto err_tsa_serial_disconnect;
+		return -ENOMEM;
 	}
 	memset(qmc->bd_table, 0, qmc->bd_size);
 
@@ -1679,8 +1664,7 @@ static int qmc_probe(struct platform_device *pdev)
 					     &qmc->int_dma_addr, GFP_KERNEL);
 	if (!qmc->int_table) {
 		dev_err(qmc->dev, "Failed to allocate interrupt table\n");
-		ret = -ENOMEM;
-		goto err_tsa_serial_disconnect;
+		return -ENOMEM;
 	}
 	memset(qmc->int_table, 0, qmc->int_size);
 
@@ -1699,18 +1683,32 @@ static int qmc_probe(struct platform_device *pdev)
 
 	ret = qmc_init_tsa(qmc);
 	if (ret)
-		goto err_tsa_serial_disconnect;
+		return ret;
 
 	qmc_write16(qmc->scc_pram + QMC_GBL_QMCSTATE, 0x8000);
 
 	ret = qmc_setup_chans(qmc);
 	if (ret)
-		goto err_tsa_serial_disconnect;
+		return ret;
 
 	/* Init interrupts table */
 	ret = qmc_setup_ints(qmc);
 	if (ret)
-		goto err_tsa_serial_disconnect;
+		return ret;
+
+	/* Connect the serial (SCC) to TSA */
+	ret = tsa_serial_connect(qmc->tsa_serial);
+	if (ret) {
+		dev_err(qmc->dev, "Failed to connect TSA serial\n");
+		return ret;
+	}
+
+	/* Init GMSR_H and GMSR_L registers */
+	qmc_write32(qmc->scc_regs + SCC_GSMRH,
+		    SCC_GSMRH_CDS | SCC_GSMRH_CTSS | SCC_GSMRH_CDP | SCC_GSMRH_CTSP);
+
+	/* enable QMC mode */
+	qmc_write32(qmc->scc_regs + SCC_GSMRL, SCC_GSMRL_MODE_QMC);
 
 	/* Disable and clear interrupts,  set the irq handler */
 	qmc_write16(qmc->scc_regs + SCC_SCCM, 0x0000);