On Mon, Nov 30, 2015 at 3:45 PM, Peter Ujfalusi <peter.ujfalusi@xxxxxx> wrote: > Hi, > > Changes since RFC v01: > - dma_request_chan(); lost the mask parameter > - The new API does not rely on RESOURCE_DMA, instead the dma_filter_map table > will be used to provide the needed information to the filter function in > legacy mode > - Extended the example patches to convert most of daVinci to use the new API to > request the DMA channels. > > TODO: Documentation update ;) > > As it has been discussed in the following thread: > http://www.gossamer-threads.com/lists/linux/kernel/2181487#2181487 > > Andy: I did looked at the unified device properties, but I decided to not to use > it as I don't see it to fit well and most of the legacy board files are using > resources to specify at least their memory regions so adding the DMA resource > to them would be more inline with the rest of the code. We could return back to this in the future, still we have to amend built-in device properties (there is a patch series already in the wild). > > The ARM, mmc and spi patches are converting daVinci drivers board files to use > the new method of requesting DMA channel. > > With this series I have taken a path which would result two new API, which can > be used to convert most of the current users already and with some work all > users might be able to move to this set. > With this set the filter_fn used for legacy (non DT/ACPI) channel request is no > longer needed to be exported to client drivers since the selection of the > correct filter_fn will be done in the core. > > So, the first proposal is to have: > > struct dma_chan *dma_request_chan(struct device *dev, const char *name); > struct dma_chan *dma_request_chan_by_mask(const dma_cap_mask_t *mask); > > The dma_request_chan_by_mask() is to request any channel matching with the > requested capabilities, can be used to request channel for memcpy, memset, xor, > etc where no hardware synchronization is needed. > > The dma_request_chan() is to request a slave channel. The dma_request_chan() will try to find the > channel via DT, ACPI or in case if the kernel booted in non DT/ACPI mode > it will use a filter lookup table and retrieves the needed information from > the dma_filter_map provided by the DMA drivers. > This legacy mode needs changes in platform code, in dmaengine drivers and > finally the dmaengine user drivers can be converted: > > For each dmaengine driver an array of DMA device, slave and the parameter > for the filter function needs to be added: > > static struct dma_filter_map da830_edma_map[] = { > DMA_FILTER_ENTRY("davinci-mcasp.0", "rx", EDMA_CTLR_CHAN(0, 0)), > DMA_FILTER_ENTRY("davinci-mcasp.0", "tx", EDMA_CTLR_CHAN(0, 1)), > DMA_FILTER_ENTRY("davinci-mcasp.1", "rx", EDMA_CTLR_CHAN(0, 2)), > DMA_FILTER_ENTRY("davinci-mcasp.1", "tx", EDMA_CTLR_CHAN(0, 3)), > DMA_FILTER_ENTRY("davinci-mcasp.2", "rx", EDMA_CTLR_CHAN(0, 4)), > DMA_FILTER_ENTRY("davinci-mcasp.2", "tx", EDMA_CTLR_CHAN(0, 5)), > DMA_FILTER_ENTRY("spi_davinci.0", "rx", EDMA_CTLR_CHAN(0, 14)), > DMA_FILTER_ENTRY("spi_davinci.0", "tx", EDMA_CTLR_CHAN(0, 15)), > DMA_FILTER_ENTRY("da830-mmc.0", "rx", EDMA_CTLR_CHAN(0, 16)), > DMA_FILTER_ENTRY("da830-mmc.0", "tx", EDMA_CTLR_CHAN(0, 17)), > DMA_FILTER_ENTRY("spi_davinci.1", "rx", EDMA_CTLR_CHAN(0, 18)), > DMA_FILTER_ENTRY("spi_davinci.1", "tx", EDMA_CTLR_CHAN(0, 19)), Does this ".2" and so prevent driver to use auto ID for platform devices? > }; > > This information is going to be needed by the dmaengine driver, so > modification to the platform_data is needed, and the driver map should be > added to the pdata of the DMA driver: > > da8xx_edma0_pdata.filter_map = da830_edma_map; > da8xx_edma0_pdata.filtercnt = ARRAY_SIZE(da830_edma_map); > > The DMA driver then needs to convigure the needed device -> filter_fn > mapping before it registers with dma_async_device_register() : > > if (info->filter_map) { > ecc->dma_slave.filter_map.map = info->filter_map; > ecc->dma_slave.filter_map.mapcnt = info->filtercnt; > ecc->dma_slave.filter_map.filter_fn = edma_filter_for_map; > } > > When neither DT or ACPI lookup is available the dma_request_chan() will > try to match the requester's device name with the filter_map's list of > device names, when a match found it will use the information from the > dma_filter_map to get the channel with the dma_get_channel() internal > function. > > Regards, > Peter > --- > Peter Ujfalusi (15): > dmaengine: core: Allow NULL mask pointer in > __dma_device_satisfies_mask() > dmaengine: core: Move and merge the code paths using private_candidate > dmaengine: core: Introduce new, universal API to request a channel > dmaengine: edma: Add support for DMA filter mapping to slave devices > ARM: davinci: devices-da8xx: Add dma_filter_map to edma > ARM: davinci: dm355: Add dma_filter_map to edma > ARM: davinci: dm365: Add dma_filter_map to edma > ARM: davinci: dm644x: Add dma_filter_map to edma > ARM: davinci: dm646x: Add dma_filter_map to edma > mmc: davinci_mmc: Use dma_request_chan() to requesting DMA channel > spi: davinci: Use dma_request_chan() to requesting DMA channel > ARM: davinci: devices-da8xx: Remove DMA resources for MMC and SPI > ARM: davinci: devices: Remove DMA resources for MMC > ARM: davinci: dm355: Remove DMA resources for SPI > ARM: davinci: dm365: Remove DMA resources for SPI > > arch/arm/mach-davinci/devices-da8xx.c | 95 ++++++++++---------- > arch/arm/mach-davinci/devices.c | 19 ---- > arch/arm/mach-davinci/dm355.c | 28 ++++-- > arch/arm/mach-davinci/dm365.c | 30 +++++-- > arch/arm/mach-davinci/dm644x.c | 12 +++ > arch/arm/mach-davinci/dm646x.c | 11 +++ > drivers/dma/dmaengine.c | 160 +++++++++++++++++++++++++--------- > drivers/dma/edma.c | 24 +++++ > drivers/mmc/host/davinci_mmc.c | 52 +++-------- > drivers/spi/spi-davinci.c | 76 +++++----------- > include/linux/dmaengine.h | 31 +++++++ > include/linux/platform_data/edma.h | 5 ++ > 12 files changed, 330 insertions(+), 213 deletions(-) > > -- > 2.6.3 > -- With Best Regards, Andy Shevchenko -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
