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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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507205632d
This patch adds a new field to the dma_slave_caps struct which indicates the granularity with which the driver is able to update the residue field of the dma_tx_state struct. Making this information available to dmaengine users allows them to make better decisions on how to operate. E.g. for audio certain features like wakeup less operation or timer based scheduling only make sense and work correctly if the reported residue is fine-grained enough. Right now four different levels of granularity are supported: * DESCRIPTOR: The DMA channel is only able to tell whether a descriptor has been completed or not, which means residue reporting is not supported by this channel. The residue field of the dma_tx_state field will always be 0. * SEGMENT: The DMA channel updates the residue field after each successfully completed segment of the transfer (For cyclic transfers this is after each period). This is typically implemented by having the hardware generate an interrupt after each transferred segment and then the drivers updates the outstanding residue by the size of the segment. Another possibility is if the hardware supports SG and the segment descriptor has a field which gets set after the segment has been completed. The driver then counts the number of segments without the flag set to compute the residue. * BURST: The DMA channel updates the residue field after each transferred burst. This is typically only supported if the hardware has a progress register of some sort (E.g. a register with the current read/write address or a register with the amount of bursts/beats/bytes that have been transferred or still need to be transferred). Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Acked-by: Vinod Koul <vinod.koul@intel.com> Signed-off-by: Mark Brown <broonie@linaro.org> |
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| acpi | ||
| asm-generic | ||
| clocksource | ||
| crypto | ||
| drm | ||
| dt-bindings | ||
| keys | ||
| kvm | ||
| linux | ||
| math-emu | ||
| media | ||
| memory | ||
| misc | ||
| net | ||
| pcmcia | ||
| ras | ||
| rdma | ||
| rxrpc | ||
| scsi | ||
| sound | ||
| target | ||
| trace | ||
| uapi | ||
| video | ||
| xen | ||
| Kbuild | ||