code.vuplus.com Git - vuplus_openvuplus_3.0/blob - meta-bsp/recipes-kernel/linux/linux-vuplus-3.14.28/linux_prevent_usb_dma_from_bmem.patch

   1 diff --git a/drivers/soc/brcmstb/bmem.c b/drivers/soc/brcmstb/bmem.c
   2 index 3d5c69b..7eb5c01 100644
   3 --- a/drivers/soc/brcmstb/bmem.c
   4 +++ b/drivers/soc/brcmstb/bmem.c
   5 @@ -188,6 +188,17 @@ void __init bmem_reserve(void)
   6                         pr_info("Reserved %lu MiB at %pa\n",
   7                                 (unsigned long) bmem_regions[i].size / SZ_1M,
   8                                 &bmem_regions[i].addr);
   9 +
  10 +                       /*
  11 +                        * Reserve the PAGE_SIZE memory preceeding each
  12 +                        * BMEM region so it's unusable by the kernel.
  13 +                        * This is to workaround a bug in the USB hardware
  14 +                        * that may pre-fetch beyond the end of a DMA buffer
  15 +                        * and read into BMEM and cause MRC errors.
  16 +                        * See: SWLINUX-3996.
  17 +                        */
  18 +                       memblock_reserve(bmem_regions[i].addr - PAGE_SIZE,
  19 +                                       PAGE_SIZE);
  20                 }
  21         }
  22  }
  23 --
  24 1.7.9.1.g8d994
  25