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
