Thank you Christian. On 06/02/2022, Christian König <christian.koenig@xxxxxxx> wrote: > Hi Amol, > > Am 05.02.22 um 10:47 schrieb Amol: . . . >> Is posting the BIOS and loading the microcode enough to get me started >> with running basic tasks (DMA transfers, simple packet processing, etc.)? > > Well yes and no. As bare minimum you need the following: > 1. Firmware loading > 2. Memory management > 3. Ring buffer setup > 4. Hardware initialization > > When that is done you can write commands into the ring buffers of the CP > or SDMA and see if they are executed (see the *_ring_test() functions in > the driver). SDMA is usually easier to get working. The DMA-ring-test of making the SDMA write into a WB location in the system RAM succeeded. The sequence followed mimics what the Linux driver does for the most part, until evergreen_gpu_init. That and the portions of power mgmt, interrupt mgmt, indirect buffer mgmt, the entire _modeset_init were skipped for now. The WB and the CP, DMA ring buffers are PAGE_SIZE buffers in the system RAM. GTT is a 512-entries table, in the BAR0 aperture, appropriately filled in to map the WB, CP and DMA buffers. > > When you got that working you can worry about IB (indirect buffers) > which are basically subroutines calls written into the ring buffers. > > Most commands (like copy from A to B, fill something, write value X to > memory or write X into register Y) can be used from the ring buffers > directly, but IIRC some context switching commands which are part of the > rendering process require special handling. > > But keep in mind that all of this will just be horrible slow because the > ASIC runs with the bootup clocks which are something like 100Mhz or even > only 17Mhz on very old models. To change that you need to implement > power management, interrupt handling etc etc.... Understood. Yes, the DPM and the IH portions. I think by programming only for the hardware I have I can manage to set them up with comparatively less effort. Thanks, Amol > > Good luck, > Christian. > >> >> Thanks, >> Amol > >
