ARM: PL08x: fix fill_bytes calculation
Russell King - ARM Linux [Mon, 3 Jan 2011 22:42:55 +0000 (22:42 +0000)]
The number of bytes we want to fill into any LLI is the minimum of:
- number of bytes remaining in the transfer
- number of bytes we can transfer in a single LLI
- number of bytes we can transfer without overflowing the source boundary
- number of bytes we can transfer without overflowing the destination boundary

The minimum of the first two is already calculated (target_len).  We
limit the boundary calculations to this number of bytes, which will
then give us the number of bytes we can place into this LLI.

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 91dd6bf..be7fa17 100644 (file)
@@ -685,31 +685,25 @@ static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x,
                        target_len = min(remainder, max_bytes_per_lli);
 
                        /*
-                        * Set bus lengths for incrementing buses
-                        * to number of bytes which fill to next memory
-                        * boundary
+                        * Set bus lengths for incrementing buses to the
+                        * number of bytes which fill to next memory boundary,
+                        * limiting on the target length calculated above.
                         */
                        if (cctl & PL080_CONTROL_SRC_INCR)
                                txd->srcbus.fill_bytes =
-                                       pl08x_pre_boundary(
-                                               txd->srcbus.addr,
-                                               remainder);
+                                       pl08x_pre_boundary(txd->srcbus.addr,
+                                               target_len);
                        else
-                               txd->srcbus.fill_bytes =
-                                       max_bytes_per_lli;
+                               txd->srcbus.fill_bytes = target_len;
 
                        if (cctl & PL080_CONTROL_DST_INCR)
                                txd->dstbus.fill_bytes =
-                                       pl08x_pre_boundary(
-                                               txd->dstbus.addr,
-                                               remainder);
+                                       pl08x_pre_boundary(txd->dstbus.addr,
+                                               target_len);
                        else
-                               txd->dstbus.fill_bytes =
-                                               max_bytes_per_lli;
+                               txd->dstbus.fill_bytes = target_len;
 
-                       /*
-                        *  Find the nearest
-                        */
+                       /* Find the nearest */
                        lli_len = min(txd->srcbus.fill_bytes,
                                txd->dstbus.fill_bytes);