dmaengine: sun6i: Add support for Allwinner A23 (sun8i) variant

The A23 SoC has the same dma engine as the A31 (sun6i), with a
reduced amount of endpoints and physical channels. Add the proper
config data and compatible string to support it.

A slight difference in sun8i is an undocumented register needs
to be toggled for dma to function.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

1 files changed, 27 insertions, 0 deletions

diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c
index 531abbf68a9d..f9f8f4d9915f 100644
--- a/drivers/dma/sun6i-dma.c
+++ b/drivers/dma/sun6i-dma.c
@@ -43,6 +43,12 @@
 #define DMA_STAT		0x30
 
 /*
+ * sun8i specific registers
+ */
+#define SUN8I_DMA_GATE		0x20
+#define SUN8I_DMA_GATE_ENABLE	0x4
+
+/*
  * Channels specific registers
  */
 #define DMA_CHAN_ENABLE		0x00
@@ -878,8 +884,20 @@ static struct sun6i_dma_config sun6i_a31_dma_cfg = {
 	.nr_max_vchans   = 53,
 };
 
+/*
+ * The A23 only has 8 physical channels, a maximum DRQ port id of 24,
+ * and a total of 37 usable source and destination endpoints.
+ */
+
+static struct sun6i_dma_config sun8i_a23_dma_cfg = {
+	.nr_max_channels = 8,
+	.nr_max_requests = 24,
+	.nr_max_vchans   = 37,
+};
+
 static struct of_device_id sun6i_dma_match[] = {
 	{ .compatible = "allwinner,sun6i-a31-dma", .data = &sun6i_a31_dma_cfg },
+	{ .compatible = "allwinner,sun8i-a23-dma", .data = &sun8i_a23_dma_cfg },
 	{ /* sentinel */ }
 };
 
@@ -1007,6 +1025,15 @@ static int sun6i_dma_probe(struct platform_device *pdev)
 		goto err_dma_unregister;
 	}
 
+	/*
+	 * sun8i variant requires us to toggle a dma gating register,
+	 * as seen in Allwinner's SDK. This register is not documented
+	 * in the A23 user manual.
+	 */
+	if (of_device_is_compatible(pdev->dev.of_node,
+				    "allwinner,sun8i-a23-dma"))
+		writel(SUN8I_DMA_GATE_ENABLE, sdc->base + SUN8I_DMA_GATE);
+
 	return 0;
 
 err_dma_unregister: