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Subject[PATCH 03/10] dmaengine: sun6i: Restructure code to allow extension for new SoCs
Date
The current code mixes three distinct operations when transforming
the slave config to register settings:

1. special handling of DMA_SLAVE_BUSWIDTH_UNDEFINED, maxburst == 0
2. range checking
3. conversion of raw to register values

As the range checks depend on the specific SoC, move these out of the
conversion to distinct operations.

Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>
---
drivers/dma/sun6i-dma.c | 58 +++++++++++++++++++++++++------------------------
1 file changed, 30 insertions(+), 28 deletions(-)

diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c
index f1a139f0102f..c5644bd0f91a 100644
--- a/drivers/dma/sun6i-dma.c
+++ b/drivers/dma/sun6i-dma.c
@@ -185,6 +185,8 @@ struct sun6i_dma_dev {
struct sun6i_pchan *pchans;
struct sun6i_vchan *vchans;
const struct sun6i_dma_config *cfg;
+ u32 src_burst_lengths;
+ u32 dst_burst_lengths;
};

static struct device *chan2dev(struct dma_chan *chan)
@@ -270,10 +272,6 @@ static inline s8 convert_burst(u32 maxburst)

static inline s8 convert_buswidth(enum dma_slave_buswidth addr_width)
{
- if ((addr_width < DMA_SLAVE_BUSWIDTH_1_BYTE) ||
- (addr_width > DMA_SLAVE_BUSWIDTH_4_BYTES))
- return -EINVAL;
-
return addr_width >> 1;
}

@@ -520,41 +518,43 @@ static int set_config(struct sun6i_dma_dev *sdev,
enum dma_transfer_direction direction,
u32 *p_cfg)
{
+ enum dma_slave_buswidth src_addr_width, dst_addr_width;
+ u32 src_maxburst, dst_maxburst;
s8 src_width, dst_width, src_burst, dst_burst;

+ src_addr_width = sconfig->src_addr_width;
+ dst_addr_width = sconfig->dst_addr_width;
+ src_maxburst = sconfig->src_maxburst;
+ dst_maxburst = sconfig->dst_maxburst;
+
switch (direction) {
case DMA_MEM_TO_DEV:
- src_burst = convert_burst(sconfig->src_maxburst ?
- sconfig->src_maxburst : 8);
- src_width = convert_buswidth(sconfig->src_addr_width !=
- DMA_SLAVE_BUSWIDTH_UNDEFINED ?
- sconfig->src_addr_width :
- DMA_SLAVE_BUSWIDTH_4_BYTES);
- dst_burst = convert_burst(sconfig->dst_maxburst);
- dst_width = convert_buswidth(sconfig->dst_addr_width);
+ if (src_addr_width == DMA_SLAVE_BUSWIDTH_UNDEFINED)
+ src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+ src_maxburst = src_maxburst ? src_maxburst : 8;
break;
case DMA_DEV_TO_MEM:
- src_burst = convert_burst(sconfig->src_maxburst);
- src_width = convert_buswidth(sconfig->src_addr_width);
- dst_burst = convert_burst(sconfig->dst_maxburst ?
- sconfig->dst_maxburst : 8);
- dst_width = convert_buswidth(sconfig->dst_addr_width !=
- DMA_SLAVE_BUSWIDTH_UNDEFINED ?
- sconfig->dst_addr_width :
- DMA_SLAVE_BUSWIDTH_4_BYTES);
+ if (dst_addr_width == DMA_SLAVE_BUSWIDTH_UNDEFINED)
+ dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+ dst_maxburst = dst_maxburst ? dst_maxburst : 8;
break;
default:
return -EINVAL;
}

- if (src_burst < 0)
- return src_burst;
- if (src_width < 0)
- return src_width;
- if (dst_burst < 0)
- return dst_burst;
- if (dst_width < 0)
- return dst_width;
+ if (!(BIT(src_addr_width) & sdev->slave.src_addr_widths))
+ return -EINVAL;
+ if (!(BIT(dst_addr_width) & sdev->slave.dst_addr_widths))
+ return -EINVAL;
+ if (!(BIT(src_maxburst) & sdev->src_burst_lengths))
+ return -EINVAL;
+ if (!(BIT(dst_maxburst) & sdev->dst_burst_lengths))
+ return -EINVAL;
+
+ src_width = convert_buswidth(src_addr_width);
+ dst_width = convert_buswidth(dst_addr_width);
+ dst_burst = convert_burst(dst_maxburst);
+ src_burst = convert_burst(src_maxburst);

*p_cfg = DMA_CHAN_CFG_SRC_WIDTH(src_width) |
DMA_CHAN_CFG_DST_WIDTH(dst_width);
@@ -1150,6 +1150,8 @@ static int sun6i_dma_probe(struct platform_device *pdev)
sdc->slave.dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
+ sdc->src_burst_lengths = BIT(1) | BIT(8);
+ sdc->dst_burst_lengths = BIT(1) | BIT(8);
sdc->slave.directions = BIT(DMA_DEV_TO_MEM) |
BIT(DMA_MEM_TO_DEV);
sdc->slave.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
--
2.14.1
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