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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>
This commit is contained in:
Stefan Brüns 2017-10-17 01:06:34 +02:00 committed by Vinod Koul
parent 12e0177055
commit 464aa6f54b
1 changed files with 26 additions and 1 deletions
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27
drivers/dma/sun6i-dma.c
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@ -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)