1. The QPIC NAND uses 3 BAM channels: command, data tx and
   data rx while EBI2 NAND uses only single ADM channel.

2. The EBI2 NAND uses normal register read buffer since this
   buffer will be remapped with dma_map_sg. The QPIC NAND will give
   register read buffer in command descriptor and the command
   descriptor will be mapped with dma_map_sg so the register buffer
   should be DMA coherent.

Signed-off-by: Abhishek Sahu <redacted>
---
 .../devicetree/bindings/mtd/qcom_nandc.txt         |  25 +++--
 drivers/mtd/nand/qcom_nandc.c                      | 106 ++++++++++++++++-----
 2 files changed, 99 insertions(+), 32 deletions(-)

diff --git a/Documentation/devicetree/bindings/mtd/qcom_nandc.txt b/Documentation/devicetree/bindings/mtd/qcom_nandc.txt
index 5d0f7ae..87b9a56 100644
--- a/Documentation/devicetree/bindings/mtd/qcom_nandc.txt
+++ b/Documentation/devicetree/bindings/mtd/qcom_nandc.txt

@@ -9,15 +9,17 @@ Required properties:
 - clock-names:		must contain "core" for the core clock and "aon" for the
 			always on clock
 - dmas:			DMA specifier, consisting of a phandle to the ADM DMA
-			controller node and the channel number to be used for
-			NAND. Refer to dma.txt and qcom_adm.txt for more details
-- dma-names:		must be "rxtx"
-- qcom,cmd-crci:	must contain the ADM command type CRCI block instance
-			number specified for the NAND controller on the given
-			platform
-- qcom,data-crci:	must contain the ADM data type CRCI block instance
-			number specified for the NAND controller on the given
-			platform
+			or BAM DMA controller node and the channel number to
+			be used for NAND. Refer to dma.txt, qcom_adm.txt(ADM)
+			and qcom/bam_dma.txt(BAM) for more details
+- dma-names:		"rxtx" - ADM
+			"tx", "rx", "cmd" - BAM
+- qcom,cmd-crci:	Only required for ADM DMA. must contain the ADM command
+			type CRCI block instance number specified for the NAND
+			controller on the given platform.
+- qcom,data-crci:	Only required for ADM DMA. must contain the ADM data
+			type CRCI block instance number specified for the NAND
+			controller on the given platform.
 - #address-cells:	<1> - subnodes give the chip-select number
 - #size-cells:		<0>
 

@@ -95,6 +97,11 @@ nand@79b0000 {
 		<&gcc GCC_QPIC_AHB_CLK>;
 	clock-names = "core", "aon";
 
+	dmas = <&qpicbam 0>,
+		<&qpicbam 1>,
+		<&qpicbam 2>;
+	dma-names = "tx", "rx", "cmd";
+
 	#address-cells = <1>;
 	#size-cells = <0>;
 

diff --git a/drivers/mtd/nand/qcom_nandc.c b/drivers/mtd/nand/qcom_nandc.c
index f55f728..520add9 100644
--- a/drivers/mtd/nand/qcom_nandc.c
+++ b/drivers/mtd/nand/qcom_nandc.c

@@ -226,6 +226,7 @@ struct nandc_regs {
  *				by upper layers directly
  * @buf_size/count/start:	markers for chip->read_buf/write_buf functions
  * @reg_read_buf:		local buffer for reading back registers via DMA
+ * @reg_read_buf_phys:		contains dma address for register read buffer
  * @reg_read_pos:		marker for data read in reg_read_buf
  *
  * @regs:			a contiguous chunk of memory for DMA register

@@ -249,9 +250,19 @@ 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 {
+		struct {
+			struct dma_chan *tx_chan;
+			struct dma_chan *rx_chan;
+			struct dma_chan *cmd_chan;
+		};
+		struct {
+			struct dma_chan *chan;
+			unsigned int cmd_crci;
+			unsigned int data_crci;
+		};
+	};
+
 	struct list_head desc_list;
 
 	u8		*data_buffer;

@@ -261,6 +272,7 @@ struct qcom_nand_controller {
 	int		buf_start;
 
 	__le32 *reg_read_buf;
+	dma_addr_t reg_read_buf_phys;
 	int reg_read_pos;
 
 	struct nandc_regs *regs;

@@ -1956,16 +1968,48 @@ static int qcom_nandc_alloc(struct qcom_nand_controller *nandc)
 	if (!nandc->regs)
 		return -ENOMEM;
 
-	nandc->reg_read_buf = devm_kzalloc(nandc->dev,
-				MAX_REG_RD * sizeof(*nandc->reg_read_buf),
-				GFP_KERNEL);
-	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->dma_bam_enabled) {
+		nandc->reg_read_buf =
+			devm_kzalloc(nandc->dev, MAX_REG_RD *
+				     sizeof(*nandc->reg_read_buf), GFP_KERNEL);
+
+		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;
+		}
+	} else {
+		nandc->reg_read_buf =
+			dmam_alloc_coherent(nandc->dev, MAX_REG_RD *
+					    sizeof(*nandc->reg_read_buf),
+					    &nandc->reg_read_buf_phys,
+					    GFP_KERNEL);
+