Messages in this thread | | | Date | Tue, 28 Aug 2018 17:45:34 +0800 | From | Jisheng Zhang <> | Subject | [PATCH v6 0/3] solve SDHCI DWC MSHC 128MB DMA boundary limitation |
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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
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