dmaengine: xilinx: dma: Enable VDMA S2MM vertical flip support

The AXI VDMA core supports Vertical Flip with S2MM as the
path when Enable Vertical Flip (Advanced tab) is selected.
Vertical flip state is exported in vdma config and depending
on IP configuration(c_enable_vert_flip) vertical flip state
is programmed in hardware.

Signed-off-by: Radhey Shyam Pandey <radheys@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

drivers/dma/xilinx/xilinx_dma.c

@@ -115,6 +115,9 @@
 #define XILINX_VDMA_REG_START_ADDRESS(n)	(0x000c + 4 * (n))
 #define XILINX_VDMA_REG_START_ADDRESS_64(n)	(0x000c + 8 * (n))
 
+#define XILINX_VDMA_REG_ENABLE_VERTICAL_FLIP	0x00ec
+#define XILINX_VDMA_ENABLE_VERTICAL_FLIP	BIT(0)
+
 /* HW specific definitions */
 #define XILINX_DMA_MAX_CHANS_PER_DEVICE	0x20
 
@@ -340,6 +343,7 @@ struct xilinx_dma_tx_descriptor {
  * @start_transfer: Differentiate b/w DMA IP's transfer
  * @stop_transfer: Differentiate b/w DMA IP's quiesce
  * @tdest: TDEST value for mcdma
+ * @has_vflip: S2MM vertical flip
  */
 struct xilinx_dma_chan {
 	struct xilinx_dma_device *xdev;
@@ -376,6 +380,7 @@ struct xilinx_dma_chan {
 	void (*start_transfer)(struct xilinx_dma_chan *chan);
 	int (*stop_transfer)(struct xilinx_dma_chan *chan);
 	u16 tdest;
+	bool has_vflip;
 };
 
 struct xilinx_dma_config {
@@ -1074,6 +1079,14 @@ static void xilinx_vdma_start_transfer(struct xilinx_dma_chan *chan)
 				desc->async_tx.phys);
 
 	/* Configure the hardware using info in the config structure */
+	if (chan->has_vflip) {
+		reg = dma_read(chan, XILINX_VDMA_REG_ENABLE_VERTICAL_FLIP);
+		reg &= ~XILINX_VDMA_ENABLE_VERTICAL_FLIP;
+		reg |= config->vflip_en;
+		dma_write(chan, XILINX_VDMA_REG_ENABLE_VERTICAL_FLIP,
+				reg);
+	}
+
 	reg = dma_ctrl_read(chan, XILINX_DMA_REG_DMACR);
 
 	if (config->frm_cnt_en)
@@ -2087,6 +2100,8 @@ int xilinx_vdma_channel_set_config(struct dma_chan *dchan,
 	}
 
 	chan->config.frm_cnt_en = cfg->frm_cnt_en;
+	chan->config.vflip_en = cfg->vflip_en;
+
 	if (cfg->park)
 		chan->config.park_frm = cfg->park_frm;
 	else
@@ -2412,6 +2427,13 @@ static int xilinx_dma_chan_probe(struct xilinx_dma_device *xdev,
 		chan->id = chan_id;
 		chan->tdest = chan_id - xdev->nr_channels;
 		xdev->common.directions |= BIT(DMA_DEV_TO_MEM);
+		chan->has_vflip = of_property_read_bool(node,
+					"xlnx,enable-vert-flip");
+		if (chan->has_vflip) {
+			chan->config.vflip_en = dma_read(chan,
+				XILINX_VDMA_REG_ENABLE_VERTICAL_FLIP) &
+				XILINX_VDMA_ENABLE_VERTICAL_FLIP;
+		}
 
 		chan->ctrl_offset = XILINX_DMA_S2MM_CTRL_OFFSET;
 		if (xdev->dma_config->dmatype == XDMA_TYPE_VDMA) {

include/linux/dma/xilinx_dma.h

@@ -27,6 +27,7 @@
  * @delay: Delay counter
  * @reset: Reset Channel
  * @ext_fsync: External Frame Sync source
+ * @vflip_en:  Vertical Flip enable
  */
 struct xilinx_vdma_config {
 	int frm_dly;
@@ -39,6 +40,7 @@ struct xilinx_vdma_config {
 	int delay;
 	int reset;
 	int ext_fsync;
+	bool vflip_en;
 };
 
 /**