DMA: PL08x: cleanup selection of burst size
Russell King - ARM Linux [Thu, 21 Jul 2011 16:14:08 +0000 (17:14 +0100)]
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>

drivers/dma/amba-pl08x.c

index a84db8b..9aa2bd4 100644 (file)
@@ -1048,50 +1048,42 @@ pl08x_dma_tx_status(struct dma_chan *chan,
 
 /* PrimeCell DMA extension */
 struct burst_table {
-       int burstwords;
+       u32 burstwords;
        u32 reg;
 };
 
 static const struct burst_table burst_sizes[] = {
        {
                .burstwords = 256,
-               .reg = (PL080_BSIZE_256 << PL080_CONTROL_SB_SIZE_SHIFT) |
-                       (PL080_BSIZE_256 << PL080_CONTROL_DB_SIZE_SHIFT),
+               .reg = PL080_BSIZE_256,
        },
        {
                .burstwords = 128,
-               .reg = (PL080_BSIZE_128 << PL080_CONTROL_SB_SIZE_SHIFT) |
-                       (PL080_BSIZE_128 << PL080_CONTROL_DB_SIZE_SHIFT),
+               .reg = PL080_BSIZE_128,
        },
        {
                .burstwords = 64,
-               .reg = (PL080_BSIZE_64 << PL080_CONTROL_SB_SIZE_SHIFT) |
-                       (PL080_BSIZE_64 << PL080_CONTROL_DB_SIZE_SHIFT),
+               .reg = PL080_BSIZE_64,
        },
        {
                .burstwords = 32,
-               .reg = (PL080_BSIZE_32 << PL080_CONTROL_SB_SIZE_SHIFT) |
-                       (PL080_BSIZE_32 << PL080_CONTROL_DB_SIZE_SHIFT),
+               .reg = PL080_BSIZE_32,
        },
        {
                .burstwords = 16,
-               .reg = (PL080_BSIZE_16 << PL080_CONTROL_SB_SIZE_SHIFT) |
-                       (PL080_BSIZE_16 << PL080_CONTROL_DB_SIZE_SHIFT),
+               .reg = PL080_BSIZE_16,
        },
        {
                .burstwords = 8,
-               .reg = (PL080_BSIZE_8 << PL080_CONTROL_SB_SIZE_SHIFT) |
-                       (PL080_BSIZE_8 << PL080_CONTROL_DB_SIZE_SHIFT),
+               .reg = PL080_BSIZE_8,
        },
        {
                .burstwords = 4,
-               .reg = (PL080_BSIZE_4 << PL080_CONTROL_SB_SIZE_SHIFT) |
-                       (PL080_BSIZE_4 << PL080_CONTROL_DB_SIZE_SHIFT),
+               .reg = PL080_BSIZE_4,
        },
        {
-               .burstwords = 1,
-               .reg = (PL080_BSIZE_1 << PL080_CONTROL_SB_SIZE_SHIFT) |
-                       (PL080_BSIZE_1 << PL080_CONTROL_DB_SIZE_SHIFT),
+               .burstwords = 0,
+               .reg = PL080_BSIZE_1,
        },
 };
 
@@ -1135,15 +1127,25 @@ static u32 pl08x_width(enum dma_slave_buswidth width)
        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,
                                  struct dma_slave_config *config)
 {
        struct pl08x_dma_chan *plchan = to_pl08x_chan(chan);
        struct pl08x_driver_data *pl08x = plchan->host;
        enum dma_slave_buswidth addr_width;
-       u32 width, maxburst;
+       u32 width, burst, maxburst;
        u32 cctl = 0;
-       int i;
 
        if (!plchan->slave)
                return -EINVAL;
@@ -1173,20 +1175,16 @@ static int dma_set_runtime_config(struct dma_chan *chan,
        cctl |= width << PL080_CONTROL_DWIDTH_SHIFT;
 
        /*
-        * Now decide on a maxburst:
         * If this channel will only request single transfers, set this
         * down to ONE element.  Also select one element if no maxburst
         * is specified.
         */
-       if (plchan->cd->single || maxburst == 0) {
-               cctl |= (PL080_BSIZE_1 << PL080_CONTROL_SB_SIZE_SHIFT) |
-                       (PL080_BSIZE_1 << PL080_CONTROL_DB_SIZE_SHIFT);
-       } else {
-               for (i = 0; i < ARRAY_SIZE(burst_sizes); i++)
-                       if (burst_sizes[i].burstwords <= maxburst)
-                               break;
-               cctl |= burst_sizes[i].reg;
-       }
+       if (plchan->cd->single)
+               maxburst = 1;
+
+       burst = pl08x_burst(maxburst);
+       cctl |= burst << PL080_CONTROL_SB_SIZE_SHIFT;
+       cctl |= burst << PL080_CONTROL_DB_SIZE_SHIFT;
 
        if (plchan->runtime_direction == DMA_FROM_DEVICE) {
                plchan->src_addr = config->src_addr;