mtd: nand: qcom: add and initialize QPIC DMA resources

1. QPIC NAND controller uses 3 BAM channels: command, data tx
   and data rx while EBI2 NAND controller uses only single ADM
   channel.
2. CRCI is only required for ADM DMA and it's not required for
   BAM DMA.
Reviewed-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Abhishek Sahu <absahu@codeaurora.org>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

drivers/mtd/nand/qcom_nandc.c

@@ -255,9 +255,22 @@ struct qcom_nand_controller {
 	struct clk *core_clk;
 	struct clk *aon_clk;
 
-	struct dma_chan *chan;
-	unsigned int cmd_crci;
-	unsigned int data_crci;
+	union {
+		/* will be used only by QPIC for BAM DMA */
+		struct {
+			struct dma_chan *tx_chan;
+			struct dma_chan *rx_chan;
+			struct dma_chan *cmd_chan;
+		};
+
+		/* will be used only by EBI2 for ADM DMA */
+		struct {
+			struct dma_chan *chan;
+			unsigned int cmd_crci;
+			unsigned int data_crci;
+		};
+	};
+
 	struct list_head desc_list;
 
 	u8		*data_buffer;
@@ -1989,10 +2002,31 @@ static int qcom_nandc_alloc(struct qcom_nand_controller *nandc)
 	if (!nandc->reg_read_buf)
 		return -ENOMEM;
 
-	nandc->chan = dma_request_slave_channel(nandc->dev, "rxtx");
-	if (!nandc->chan) {
-		dev_err(nandc->dev, "failed to request slave channel\n");
-		return -ENODEV;
+	if (nandc->props->is_bam) {
+		nandc->tx_chan = dma_request_slave_channel(nandc->dev, "tx");
+		if (!nandc->tx_chan) {
+			dev_err(nandc->dev, "failed to request tx channel\n");
+			return -ENODEV;
+		}
+
+		nandc->rx_chan = dma_request_slave_channel(nandc->dev, "rx");
+		if (!nandc->rx_chan) {
+			dev_err(nandc->dev, "failed to request rx channel\n");
+			return -ENODEV;
+		}
+
+		nandc->cmd_chan = dma_request_slave_channel(nandc->dev, "cmd");
+		if (!nandc->cmd_chan) {
+			dev_err(nandc->dev, "failed to request cmd channel\n");
+			return -ENODEV;
+		}
+	} else {
+		nandc->chan = dma_request_slave_channel(nandc->dev, "rxtx");
+		if (!nandc->chan) {
+			dev_err(nandc->dev,
+				"failed to request slave channel\n");
+			return -ENODEV;
+		}
 	}
 
 	INIT_LIST_HEAD(&nandc->desc_list);
@@ -2005,7 +2039,19 @@ static int qcom_nandc_alloc(struct qcom_nand_controller *nandc)
 
 static void qcom_nandc_unalloc(struct qcom_nand_controller *nandc)
 {
-	dma_release_channel(nandc->chan);
+	if (nandc->props->is_bam) {
+		if (nandc->tx_chan)
+			dma_release_channel(nandc->tx_chan);
+
+		if (nandc->rx_chan)
+			dma_release_channel(nandc->rx_chan);
+
+		if (nandc->cmd_chan)
+			dma_release_channel(nandc->cmd_chan);
+	} else {
+		if (nandc->chan)
+			dma_release_channel(nandc->chan);
+	}
 }
 
 /* one time setup of a few nand controller registers */
@@ -2146,16 +2192,20 @@ static int qcom_nandc_parse_dt(struct platform_device *pdev)
 	struct device_node *np = nandc->dev->of_node;
 	int ret;
 
-	ret = of_property_read_u32(np, "qcom,cmd-crci", &nandc->cmd_crci);
-	if (ret) {
-		dev_err(nandc->dev, "command CRCI unspecified\n");
-		return ret;
-	}
+	if (!nandc->props->is_bam) {
+		ret = of_property_read_u32(np, "qcom,cmd-crci",
+					   &nandc->cmd_crci);
+		if (ret) {
+			dev_err(nandc->dev, "command CRCI unspecified\n");
+			return ret;
+		}
 
-	ret = of_property_read_u32(np, "qcom,data-crci", &nandc->data_crci);
-	if (ret) {
-		dev_err(nandc->dev, "data CRCI unspecified\n");
-		return ret;
+		ret = of_property_read_u32(np, "qcom,data-crci",
+					   &nandc->data_crci);
+		if (ret) {
+			dev_err(nandc->dev, "data CRCI unspecified\n");
+			return ret;
+		}
 	}
 
 	return 0;
@@ -2205,7 +2255,7 @@ static int qcom_nandc_probe(struct platform_device *pdev)
 
 	ret = qcom_nandc_alloc(nandc);
 	if (ret)
-		return ret;
+		goto err_core_clk;
 
 	ret = clk_prepare_enable(nandc->core_clk);
 	if (ret)