1 files changed, 26 insertions, 1 deletions

diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c
index 0cabb48b0fb5..0cd13f17fc11 100644
--- a/drivers/dma/sun6i-dma.c
+++ b/drivers/dma/sun6i-dma.c
@@ -42,6 +42,9 @@
 
 #define DMA_STAT                0x30
 
+/* Offset between DMA_IRQ_EN and DMA_IRQ_STAT limits number of channels */
+#define DMA_MAX_CHANNELS        (DMA_IRQ_CHAN_NR * 0x10 / 4)
+
 /*
  * sun8i specific registers
  */
@@ -65,7 +68,8 @@
 #define DMA_CHAN_LLI_ADDR       0x08
 
 #define DMA_CHAN_CUR_CFG        0x0c
-#define DMA_CHAN_CFG_SRC_DRQ(x)         ((x) & 0x1f)
+#define DMA_CHAN_MAX_DRQ                0x1f
+#define DMA_CHAN_CFG_SRC_DRQ(x)         ((x) & DMA_CHAN_MAX_DRQ)
 #define DMA_CHAN_CFG_SRC_IO_MODE        BIT(5)
 #define DMA_CHAN_CFG_SRC_LINEAR_MODE    (0 << 5)
 #define DMA_CHAN_CFG_SRC_BURST_A31(x)   (((x) & 0x3) << 7)
@@ -1174,6 +1178,7 @@ MODULE_DEVICE_TABLE(of, sun6i_dma_match);
 
 static int sun6i_dma_probe(struct platform_device *pdev)
 {
+        struct device_node *np = pdev->dev.of_node;
         struct sun6i_dma_dev *sdc;
         struct resource *res;
         int ret, i;
@@ -1248,6 +1253,26 @@ static int sun6i_dma_probe(struct platform_device *pdev)
         sdc->num_vchans = sdc->cfg->nr_max_vchans;
         sdc->max_request = sdc->cfg->nr_max_requests;
 
+        ret = of_property_read_u32(np, "dma-channels", &sdc->num_pchans);
+        if (ret && !sdc->num_pchans) {
+                dev_err(&pdev->dev, "Can't get dma-channels.\n");
+                return ret;
+        }
+
+        ret = of_property_read_u32(np, "dma-requests", &sdc->max_request);
+        if (ret && !sdc->max_request) {
+                dev_info(&pdev->dev, "Missing dma-requests, using %u.\n",
+                         DMA_CHAN_MAX_DRQ);
+                sdc->max_request = DMA_CHAN_MAX_DRQ;
+        }
+
+        /*
+         * If the number of vchans is not specified, derive it from the
+         * highest port number, at most one channel per port and direction.
+         */
+        if (!sdc->num_vchans)
+                sdc->num_vchans = 2 * (sdc->max_request + 1);
+
         sdc->pchans = devm_kcalloc(&pdev->dev, sdc->num_pchans,
                                    sizeof(struct sun6i_pchan), GFP_KERNEL);
         if (!sdc->pchans)