dmaengine: pxa_dma: fix residue corner case

[uclinux-h8/linux.git] / drivers / dma / pxa_dma.c

diff --git a/drivers/dma/pxa_dma.c b/drivers/dma/pxa_dma.c
index 064a826..fc4156a 100644 (file)
--- a/drivers/dma/pxa_dma.c
+++ b/drivers/dma/pxa_dma.c
@@ -1186,6 +1186,16 @@ static unsigned int pxad_residue(struct pxad_chan *chan,
        else
                curr = phy_readl_relaxed(chan->phy, DTADR);
 
+       /*
+        * curr has to be actually read before checking descriptor
+        * completion, so that a curr inside a status updater
+        * descriptor implies the following test returns true, and
+        * preventing reordering of curr load and the test.
+        */
+       rmb();
+       if (is_desc_completed(vd))
+               goto out;
+
        for (i = 0; i < sw_desc->nb_desc - 1; i++) {
                hw_desc = sw_desc->hw_desc[i];
                if (sw_desc->hw_desc[0]->dcmd & PXA_DCMD_INCSRCADDR)