ARM: PL08x: fix array overflow in dma_set_runtime_config()

If maxburst was passed in as zero, we would overflow the burst_sizes[]
array.  Fix this by checking for this condition, and defaulting to
single transfer 'bursts'.

Improve the readability of the loop using a for() loop rather than
a while() loop with the iterator initialized far from the loop.

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>

1 files changed, 6 insertions, 7 deletions

diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c
index 3da49ed5f800..0809810f9e7a 100644
--- a/drivers/dma/amba-pl08x.c
+++ b/drivers/dma/amba-pl08x.c
@@ -1207,7 +1207,7 @@ static void dma_set_runtime_config(struct dma_chan *chan,
         u32 cctl = 0;
         /* Mask out all except src and dst channel */
         u32 ccfg = cd->ccfg & 0x000003DEU;
-        int i = 0;
+        int i;
 
         /* Transfer direction */
         plchan->runtime_direction = config->direction;
@@ -1250,18 +1250,17 @@ static void dma_set_runtime_config(struct dma_chan *chan,
 
         /*
          * Now decide on a maxburst:
-         * If this channel will only request single transfers, set
-         * this down to ONE element.
+         * 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) {
+        if (plchan->cd->single || maxburst == 0) {
                 cctl |= (PL080_BSIZE_1 << PL080_CONTROL_SB_SIZE_SHIFT) |
                         (PL080_BSIZE_1 << PL080_CONTROL_DB_SIZE_SHIFT);
         } else {
-                while (i < ARRAY_SIZE(burst_sizes)) {
+                for (i = 0; i < ARRAY_SIZE(burst_sizes); i++)
                         if (burst_sizes[i].burstwords <= maxburst)
                                 break;
-                        i++;
-                }
                 cctl |= burst_sizes[i].reg;
         }