target/linux/brcm2708/patches-4.19/950-0327-bcm2835-sdhost-Allow-for-sg-entries-that-cross-pages.patch

   1 From 44db7882be675cdf2d89741af5bbeba41b3e25af Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.org>
   3 Date: Wed, 13 Mar 2019 14:19:11 +0000
   4 Subject: [PATCH] bcm2835-sdhost: Allow for sg entries that cross pages
   5
   6 The dma_complete handling code calculates a virtual address for a page
   7 then adds an offset, but if the offset is more than a page and HIGHMEM
   8 is in use then the summed address could be in an unmapped (or just
   9 incorrect) page.
  10
  11 The upstream SDHOST driver allows for this possibility - copy the code
  12 that does so.
  13
  14 Signed-off-by: Phil Elwell <phil@raspberrypi.org>
  15 ---
  16  drivers/mmc/host/bcm2835-sdhost.c | 5 +++++
  17  1 file changed, 5 insertions(+)
  18
  19 --- a/drivers/mmc/host/bcm2835-sdhost.c
  20 +++ b/drivers/mmc/host/bcm2835-sdhost.c
  21 @@ -543,6 +543,11 @@ static void bcm2835_sdhost_dma_complete(
  22                 void *page;
  23                 u32 *buf;
  24
  25 +               if (host->drain_offset & PAGE_MASK) {
  26 +                       host->drain_page += host->drain_offset >> PAGE_SHIFT;
  27 +                       host->drain_offset &= ~PAGE_MASK;
  28 +               }
  29 +
  30                 page = kmap_atomic(host->drain_page);
  31                 buf = page + host->drain_offset;
  32