1be5336bc7
With the old binding and driver architecture we had many issues: No way to assign eDMA channels to event queues, thus not able to tune the system by moving specific DMA channels to low/high priority servicing. We moved the cyclic channels to high priority within the code, but that was just a workaround to this issue. Memcopy was fundamentally broken: even if the driver scanned the DT/devices in the booted system for direct DMA users (which is not effective when the events are going through a crossbar) and created a map of 'used' channels, this information was not really usable. Since via dmaengien API the eDMA driver will be called with _some_ channel number, we would try to request this channel when any channel is requested for memcpy. By luck we got channel which is not used by any device most of the time so things worked, but if a device would have been using the given channel, but not requested it, the memcpy channel would have been waiting for HW event. The old code had the am33xx/am43xx DMA event router handling embedded. This should have been done in a separate driver since it is not part of the actual eDMA IP. There were no way to 'lock' PaRAM slots to be used by the DSP for example when booting with DT. In DT boot the edma node used more than one hwmod which is not a good practice and the kernel prints warning because of this. With the new bindings and the changes in the driver we can: - No regression with Legacy binding and non DT boot - DMA channels can be assigned to any TC (to set priority) - PaRAM slots can be reserved for other cores to use - Dynamic power management for CC and TCs, if only TC0 is used all other TC can be powered down for example Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com> |
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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 | ||
| soc | ||
| sound | ||
| target | ||
| trace | ||
| uapi | ||
| video | ||
| xen | ||
| Kbuild | ||