ARM: PL08x: assign ccfg DMA request signal in prep_phy_channel()
Russell King - ARM Linux [Mon, 3 Jan 2011 22:39:53 +0000 (22:39 +0000)]
There is no need to wait until we start processing a tx descriptor
before setting up the DMA request selection in the ccfg register.
We know which channel and request will be used in prep_phy_channel(),
so setup the ccfg request selection at txd creation time in
prep_phy_channel().

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/dma/amba-pl08x.c

index 75f9e2d..f0a2988 100644 (file)
@@ -194,18 +194,10 @@ static void pl08x_start_txd(struct pl08x_dma_chan *plchan,
        struct pl08x_driver_data *pl08x = plchan->host;
        struct pl08x_phy_chan *phychan = plchan->phychan;
        struct pl08x_lli *lli = &txd->llis_va[0];
-       u32 val, ccfg = txd->ccfg;
+       u32 val;
 
        plchan->at = txd;
 
-       /* Assign the flow control signal to this channel */
-       if (txd->direction == DMA_TO_DEVICE)
-               /* Select signal as destination */
-               ccfg |= phychan->signal << PL080_CONFIG_DST_SEL_SHIFT;
-       else if (txd->direction == DMA_FROM_DEVICE)
-               /* Select signal as source */
-               ccfg |= phychan->signal << PL080_CONFIG_SRC_SEL_SHIFT;
-
        /* Wait for channel inactive */
        while (pl08x_phy_channel_busy(phychan))
                cpu_relax();
@@ -214,13 +206,13 @@ static void pl08x_start_txd(struct pl08x_dma_chan *plchan,
                "WRITE channel %d: csrc=0x%08x, cdst=0x%08x, "
                "clli=0x%08x, cctl=0x%08x, ccfg=0x%08x\n",
                phychan->id, lli->src, lli->dst, lli->lli, lli->cctl,
-               ccfg);
+               txd->ccfg);
 
        writel(lli->src, phychan->base + PL080_CH_SRC_ADDR);
        writel(lli->dst, phychan->base + PL080_CH_DST_ADDR);
        writel(lli->lli, phychan->base + PL080_CH_LLI);
        writel(lli->cctl, phychan->base + PL080_CH_CONTROL);
-       writel(ccfg, phychan->base + PL080_CH_CONFIG);
+       writel(txd->ccfg, phychan->base + PL080_CH_CONFIG);
 
        /* Enable the DMA channel */
        /* Do not access config register until channel shows as disabled */
@@ -1001,6 +993,12 @@ static int prep_phy_channel(struct pl08x_dma_chan *plchan,
                        return -EBUSY;
                }
                ch->signal = ret;
+
+               /* Assign the flow control signal to this channel */
+               if (txd->direction == DMA_TO_DEVICE)
+                       txd->ccfg |= ch->signal << PL080_CONFIG_DST_SEL_SHIFT;
+               else if (txd->direction == DMA_FROM_DEVICE)
+                       txd->ccfg |= ch->signal << PL080_CONFIG_SRC_SEL_SHIFT;
        }
 
        dev_dbg(&pl08x->adev->dev, "allocated physical channel %d and signal %d for xfer on %s\n",