On 17/12/2018 21.16, Aaro Koskinen wrote: > On Thu, Nov 22, 2018 at 03:12:36PM +0000, Russell King - ARM Linux wrote: >> Also we can't deal with the omap_set_dma_dest_burst_mode() setting - >> DMAengine always uses a 64 byte burst, but udc wants a smaller burst >> setting. Does this matter? > > Looking at OMAP1 docs, it seems it supports only 16 bytes. Then checking > DMAengine code, I don't think these CSDP bit values are not valid > for OMAP1: > > CSDP_SRC_BURST_1 = 0 << 7, > CSDP_SRC_BURST_16 = 1 << 7, > CSDP_SRC_BURST_32 = 2 << 7, > CSDP_SRC_BURST_64 = 3 << 7, > > From TI SPRU674 document, pages 50-51: > > 0 single access (no burst) > 1 single access (no burst) > 2 burst 4 In omap1510 it is 4 x data_type In omap1610/1710 it is 4 x data_type (only data_type == 32bit is supported) >From omap2420+ 32 bytes (8x32bit/4x64bit) So for OMAP1 we need to have different handling of the burst: only enable if data_type is 32bit. > 3 reserved (do not use this setting) > > So if CSDP_SRC_BURST_64 (3) gets programmed OMAP1, I wonder what is the > end result, no burst or burst 4... > > A. > - Péter Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
