v2013/7/14 Gerhard Sittig <g...@denx.de>: > this series > - introduces slave s/g support (that's support for DMA transfers which > involve peripherals in contrast to mem-to-mem transfers) > - adds device tree based lookup support for DMA channels > - combines floating patches and related feedback which already covered > several aspects of what the suggested LPB driver needs, to demonstrate > how integration might be done > - carries Q&D SD card support to enable another DMA client during test, > while this patch needs to get dropped upon pickup > > changes since v1: > - re-order mpc8308 related code paths for improved readability, no > change in behaviour, introduction of symbolic channel names here > already > - squash 'execute() start condition' and 'terminate all' into the > introduction of 'slave s/g prep' and 'device control' support; refuse > s/g lists with more than one item since slave support is operational > yet proper s/g support is missing (can get addressed later) > - always start transfers from software on MPC8308 as there are no > external request lines for peripheral flow control > - drop dt-bindings header file and symbolic channel names in OF nodes
Changes since v2 (RFC v3 was badly formed, excuse me for that): Part 1/5: - use #define instead of enum since individual channels don't require special handling. Part 2/5: - add a flag "will_access_peripheral" to DMA transfer descriptor according recommendations of Gerhard Sittig. This flag is set in mpc_dma_prep_memcpy() and mpc_dma_prep_slave_sg() and is evaluated in mpc_dma_execute() to choose a type of start for the transfer. - prevent descriptors of transfers which involve peripherals from being chained together; each of such transfers needs hardware initiated start. - add locking while working with struct mpc_dma_chan according recommendations of Lars-Peter Clausen. - remove default nbytes value. Client kernel modules must set src_maxburst and dst_maxburst fields of struct dma_slave_config (dmaengine.h). Part 6/8: unchanged. Part 7/8: unchanged. Part 8/8: unchanged. These changes are tested on MPC5125 - with SCLPC driver (transfers between dev and mem work fine). - with dmatest module (all 64 DMA channels can perform mem-to-mem transfers which can be chained in one DMA transaction). > known issues: > - it's yet to get confirmed whether MPC8308 can use slave support or > whether the DMA controller's driver shall actively reject it, the > information that's available so far suggests that peripheral transfers > to IP bus attached I/O is useful and shall not get blocked right away > _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
