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authorStefan Brüns <stefan.bruens@rwth-aachen.de>2017-10-17 02:06:34 +0300
committerVinod Koul <vinod.koul@intel.com>2017-10-23 09:14:03 +0300
commit464aa6f54b093df1ccaff6558207f8bf68a69c37 (patch)
tree5e85763517793b83e2e0ea1edf533d2ec745e76b /drivers/dma/sun6i-dma.c
parent12e0177055ee4b5ab656414b32054e64568160d8 (diff)
downloadlinux-464aa6f54b093df1ccaff6558207f8bf68a69c37.tar.xz
dmaengine: sun6i: Retrieve channel count/max request from devicetree
To avoid introduction of a new compatible for each small SoC/DMA controller variation, move the definition of the channel count to the devicetree. The number of vchans is no longer explicit, but limited by the highest port/DMA request number. The result is a slight overallocation for SoCs with a sparse port mapping. Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de> Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Diffstat (limited to 'drivers/dma/sun6i-dma.c')
-rw-r--r--drivers/dma/sun6i-dma.c27
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)