On 20/11/2018 23.04, Aaro Koskinen wrote: > Hi, > > On Tue, Nov 20, 2018 at 09:28:37AM +0200, Peter Ujfalusi wrote: >> On 19/11/2018 20.46, Aaro Koskinen wrote: >>> On Mon, Nov 19, 2018 at 12:40:40PM +0200, Peter Ujfalusi wrote: >>>> When the channel is configured for slave operation the LCH_TYPE needs to be >>>> set to LCh-P. For memcpy channels the LCH_TYPE must be set to LCh-2D. >>>> >>>> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@xxxxxx> >>> >>> I don't have the documentation, but based on what omap_udc driver (still >>> using the legacy OMAP DMA API) does this seems to be correct. >> >> They are hard to fine, true. From the omap1710 TRM: >> >> Logical channel types (LCh types) supported are: >> - LCh-2D for nonsynchronized transfers (memory transfers, 1D and 2D) >> - LCh-P for synchronized transfers (mostly peripheral transfers) >> - LCh-PD similar to LCh-P but runs on a dedicated physical channel >> - LCh-G for graphical transfers/operations >> - LCh-D for display transfers > > (I found a public document "OMAP5912 Multimedia Processor Direct > Memory Access (DMA) Support Reference Guide", documenting these; easy > to confuse with "OMAP5910 Dual-Core Processor System DMA Controller > Reference Guide".) > >> Looking at other part it looks like hat LCH-2D channel mode can happily >> service a peripheral. LCH-P supports the same features as LCH-2D, but it >> lacks support for Single/Double-indexed addressing mode on the >> peripheral port side. >> >> So, this patch might not be needed at all. Can you test the omap_udc >> with s/OMAP_DMA_LCH_P/OMAP_DMA_LCH_2D >> >> If USB works, then we can just drop this patch. > > Unfortunately omap_udc does not seem to work at all anymore with DMA on > my 770 setup. :-( > > I had switched to PIO mode in 2015 since the WARNs about legacy DMA > API were too annoying and flooding the console. And now that I tried > using DMA again with g_ether, it doesn't work anymore. The device get's > recognized on host side, but no traffic goes through. Switching back to > PIO makes it to work again. After some tinkering I got omap_udc working with DMA (not DMAengine, yet) on 770 - using nfsroot. Configuring the channels to OMAP_DMA_LCH_2D works as expected. This patch can be dropped. - Péter Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
