[PATCH 1/2] mmc: renesas_sdhi: fix swiotlb buffer is full

Yoshihiro Shimoda
2017-10-17T07:34:20Z

Since the commit de3ee99b097d ("mmc: Delete bounce buffer handling")
deletes the bounce buffer handling, a request data size will be referred
to max_{req,seg}_size instead of MMC_QUEUE_BOUNCESZ (64k bytes).

In other hand, renesas_sdhi_internal_dmac.c will set very big value of
max_{req,seg}_size because the max_blk_count is set to 0xffffffff.
And then, "swiotlb buffer is full" happens because swiotlb can handle
a memory size up to 256k bytes only (IO_TLB_SEGSIZE = 128 and
IO_TLB_SHIFT = 11).

So, this patch fixes the issue to set max_blk_count to 512. Then,
the max_{req,seg}_size will be set to 256k bytes.

Reported-by: Dirk Behme <dirk.behme@de.bosch.com>
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
---
drivers/mmc/host/renesas_sdhi_internal_dmac.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/renesas_sdhi_internal_dmac.c b/drivers/mmc/host/renesas_sdhi_internal_dmac.c
index f905f23..6c9b4b2 100644
--- a/drivers/mmc/host/renesas_sdhi_internal_dmac.c
+++ b/drivers/mmc/host/renesas_sdhi_internal_dmac.c
@@ -80,8 +80,9 @@
.scc_offset = 0x1000,
.taps = rcar_gen3_scc_taps,
.taps_num = ARRAY_SIZE(rcar_gen3_scc_taps),
- /* Gen3 SDHI DMAC can handle 0xffffffff blk count, but seg = 1 */
- .max_blk_count = 0xffffffff,
+ /* The swiotlb can handle memory size up to 256 kbytes for now. */
+ .max_blk_count = 512,
+ /* Gen3 SDHI DMAC cannot handle scatter-gather. So, max_segs = 1 */
.max_segs = 1,
};

--
1.9.1