mmc: sdhci: add quirk for max len ADMA descriptors

Some controllers misparse segment length 0 as being 0, not 65536. Add
a quirk to deal with it.

Signed-off-by: Olof Johansson <olof@lixom.net>
Reviewed-by: Chris Ball <cjb@laptop.org>
Signed-off-by: Chris Ball <cjb@laptop.org>

1 files changed, 7 insertions, 3 deletions

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index d5febe584b05..9e15f41f87be 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1949,10 +1949,14 @@ int sdhci_add_host(struct sdhci_host *host)
          * of bytes. When doing hardware scatter/gather, each entry cannot
          * be larger than 64 KiB though.
          */
-        if (host->flags & SDHCI_USE_ADMA)
-                mmc->max_seg_size = 65536;
-        else
+        if (host->flags & SDHCI_USE_ADMA) {
+                if (host->quirks & SDHCI_QUIRK_BROKEN_ADMA_ZEROLEN_DESC)
+                        mmc->max_seg_size = 65535;
+                else
+                        mmc->max_seg_size = 65536;
+        } else {
                 mmc->max_seg_size = mmc->max_req_size;
+        }
 
         /*
          * Maximum block size. This varies from controller to controller and