On 28 August 2018 at 11:45, Jisheng Zhang [off-list ref] wrote:

When using DMA, if the DMA addr spans 128MB boundary, we have to split
the DMA transfer into two so that each one doesn't exceed the boundary.

patch1 adds adma_table_cnt to struct sdhci_host so that driver can
control the ADMA table count.
patch2 introduces adma_write_desc() hook to struct sdhci_ops so that
driver can override it.
patch3 finally solves the 128MB boundary limitation.

since v5:
  - use dma_get_required_mask() to calculate the extra adma_table_cnt

since v4:
  - add Adrian's ack to patch 1 and patch 2
  - address Adrian's comment -- if the boundary is fine, we have to
    return after writing dma desc once; adma_table_cnt updating could
    make use of the fact that it's already initialized by the common
    sdhci code, we just need to tune.

since v3:
  - s/adma_table_num/adma_table_cnt
  - add comment to adma_table_cnt
  - make the exported function name without the _
  - let sdhci_adma_write_desc() accept &desc param and set the new desc
    value

since v2:
  - make use of "likely" to check (!len || BOUNDARY_OK(addr, len))
  - explicitly include <linux/sizes.h> for SZ_128M

since v1:
  - fix BOUNDARY_OK macro if addr+len is aligned to 128MB
  - use DIV_ROUND_UP to cal extra desc num
  - fix !len for dwcmshc_adma_write_desc()



Jisheng Zhang (3):
  mmc: sdhci: add adma_table_cnt member to struct sdhci_host
  mmc: sdhci: introduce adma_write_desc() hook to struct sdhci_ops
  mmc: sdhci-of-dwcmshc: solve 128MB DMA boundary limitation

 drivers/mmc/host/sdhci-of-dwcmshc.c | 39 +++++++++++++++++++++
 drivers/mmc/host/sdhci.c            | 54 +++++++++++++++++------------
 drivers/mmc/host/sdhci.h            |  7 ++++
 3 files changed, 78 insertions(+), 22 deletions(-)

--
2.18.0

Applied for next, thanks!

Kind regards
Uffe