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DMA: PL08x: cleanup selection of burst size

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Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This commit is contained in:
Russell King - ARM Linux 2011-07-21 17:14:08 +01:00 committed by Vinod Koul
parent 121c8476a3
commit 760596c6b9
1 changed files with 28 additions and 30 deletions
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58
drivers/dma/amba-pl08x.c
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@ -1048,50 +1048,42 @@ pl08x_dma_tx_status(struct dma_chan *chan,
/* PrimeCell DMA extension */ /* PrimeCell DMA extension */
struct burst_table { struct burst_table {
int burstwords; u32 burstwords;
u32 reg; u32 reg;
}; };
static const struct burst_table burst_sizes[] = { static const struct burst_table burst_sizes[] = {
{ {
.burstwords = 256, .burstwords = 256,
.reg = (PL080_BSIZE_256 << PL080_CONTROL_SB_SIZE_SHIFT) | .reg = PL080_BSIZE_256,
(PL080_BSIZE_256 << PL080_CONTROL_DB_SIZE_SHIFT),
}, },
{ {
.burstwords = 128, .burstwords = 128,
.reg = (PL080_BSIZE_128 << PL080_CONTROL_SB_SIZE_SHIFT) | .reg = PL080_BSIZE_128,
(PL080_BSIZE_128 << PL080_CONTROL_DB_SIZE_SHIFT),
}, },
{ {
.burstwords = 64, .burstwords = 64,
.reg = (PL080_BSIZE_64 << PL080_CONTROL_SB_SIZE_SHIFT) | .reg = PL080_BSIZE_64,
(PL080_BSIZE_64 << PL080_CONTROL_DB_SIZE_SHIFT),
}, },
{ {
.burstwords = 32, .burstwords = 32,
.reg = (PL080_BSIZE_32 << PL080_CONTROL_SB_SIZE_SHIFT) | .reg = PL080_BSIZE_32,
(PL080_BSIZE_32 << PL080_CONTROL_DB_SIZE_SHIFT),
}, },
{ {
.burstwords = 16, .burstwords = 16,
.reg = (PL080_BSIZE_16 << PL080_CONTROL_SB_SIZE_SHIFT) | .reg = PL080_BSIZE_16,
(PL080_BSIZE_16 << PL080_CONTROL_DB_SIZE_SHIFT),
}, },
{ {
.burstwords = 8, .burstwords = 8,
.reg = (PL080_BSIZE_8 << PL080_CONTROL_SB_SIZE_SHIFT) | .reg = PL080_BSIZE_8,
(PL080_BSIZE_8 << PL080_CONTROL_DB_SIZE_SHIFT),
}, },
{ {
.burstwords = 4, .burstwords = 4,
.reg = (PL080_BSIZE_4 << PL080_CONTROL_SB_SIZE_SHIFT) | .reg = PL080_BSIZE_4,
(PL080_BSIZE_4 << PL080_CONTROL_DB_SIZE_SHIFT),
}, },
{ {
.burstwords = 1, .burstwords = 0,
.reg = (PL080_BSIZE_1 << PL080_CONTROL_SB_SIZE_SHIFT) | .reg = PL080_BSIZE_1,
(PL080_BSIZE_1 << PL080_CONTROL_DB_SIZE_SHIFT),
}, },
}; };
@ -1135,15 +1127,25 @@ static u32 pl08x_width(enum dma_slave_buswidth width)
return ~0; return ~0;
} }
static u32 pl08x_burst(u32 maxburst)
{
int i;
for (i = 0; i < ARRAY_SIZE(burst_sizes); i++)
if (burst_sizes[i].burstwords <= maxburst)
break;
return burst_sizes[i].reg;
}
static int dma_set_runtime_config(struct dma_chan *chan, static int dma_set_runtime_config(struct dma_chan *chan,
struct dma_slave_config *config) struct dma_slave_config *config)
{ {
struct pl08x_dma_chan *plchan = to_pl08x_chan(chan); struct pl08x_dma_chan *plchan = to_pl08x_chan(chan);
struct pl08x_driver_data *pl08x = plchan->host; struct pl08x_driver_data *pl08x = plchan->host;
enum dma_slave_buswidth addr_width; enum dma_slave_buswidth addr_width;
u32 width, maxburst; u32 width, burst, maxburst;
u32 cctl = 0; u32 cctl = 0;
int i;
if (!plchan->slave) if (!plchan->slave)
return -EINVAL; return -EINVAL;
@ -1173,20 +1175,16 @@ static int dma_set_runtime_config(struct dma_chan *chan,
cctl |= width << PL080_CONTROL_DWIDTH_SHIFT; cctl |= width << PL080_CONTROL_DWIDTH_SHIFT;
/* /*
* Now decide on a maxburst:
* If this channel will only request single transfers, set this * If this channel will only request single transfers, set this
* down to ONE element. Also select one element if no maxburst * down to ONE element. Also select one element if no maxburst
* is specified. * is specified.
*/ */
if (plchan->cd->single || maxburst == 0) { if (plchan->cd->single)
cctl |= (PL080_BSIZE_1 << PL080_CONTROL_SB_SIZE_SHIFT) | maxburst = 1;
(PL080_BSIZE_1 << PL080_CONTROL_DB_SIZE_SHIFT);
} else { burst = pl08x_burst(maxburst);
for (i = 0; i < ARRAY_SIZE(burst_sizes); i++) cctl |= burst << PL080_CONTROL_SB_SIZE_SHIFT;
if (burst_sizes[i].burstwords <= maxburst) cctl |= burst << PL080_CONTROL_DB_SIZE_SHIFT;
break;
cctl |= burst_sizes[i].reg;
}
if (plchan->runtime_direction == DMA_FROM_DEVICE) { if (plchan->runtime_direction == DMA_FROM_DEVICE) {
plchan->src_addr = config->src_addr; plchan->src_addr = config->src_addr;