dma: pl330: Align DMA memcpy operations to MFIFO width

[platform/kernel/linux-arm64.git] / drivers / dma / pl330.c

diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
index 2e147cb..56ad8e6 100644 (file)
--- a/drivers/dma/pl330.c
+++ b/drivers/dma/pl330.c
@@ -2759,8 +2759,13 @@ pl330_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dst,
        /* Select max possible burst size */
        burst = pi->pcfg.data_bus_width / 8;
 
+       /*
+        * Make sure we use a burst size that aligns with all the memcpy
+        * parameters because our DMA programming algorithm doesn't cope with
+        * transfers which straddle an entry in the DMA device's MFIFO.
+        */
        while (burst > 1) {
-               if (!(len % burst))
+               if (!((src | dst | len) % burst))
                        break;
                burst /= 2;
        }
@@ -2769,6 +2774,13 @@ pl330_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dst,
        while (burst != (1 << desc->rqcfg.brst_size))
                desc->rqcfg.brst_size++;
 
+       /*
+        * If burst size is smaller than bus width then make sure we only
+        * transfer one at a time to avoid a burst stradling an MFIFO entry.
+        */
+       if (desc->rqcfg.brst_size * 8 < pi->pcfg.data_bus_width)
+               desc->rqcfg.brst_len = 1;
+
        desc->rqcfg.brst_len = get_burst_len(desc, len);
 
        desc->txd.flags = flags;