On Thursday, July 23, 2015 at 07:03:47 PM, Michal Suchanek wrote: Hi! [...] > >>> It's probably slower to set up DMA for 2-byte commands but it might > >>> work nonetheless. > >> > >> It is, the overhead will be considerable. It might help the stability > >> though. I'm really looking forward to the results! > > > > Hello, > > > > this does not quite work. > > > > My test with spidev: > > > > # ./spinor /dev/spidev1.0 > > Sending 9f 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > > Received 00 ff c8 60 16 c8 60 16 c8 60 16 c8 60 16 c8 60 > > Sending 90 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > > Received 00 ff ff ff ff c8 15 c8 15 c8 15 c8 15 c8 15 c8 > > Sending 9f 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > > Received 00 ff c8 60 16 c8 60 16 c8 60 16 c8 60 16 c8 60 > > > > I receive correct ID but spi-nor complains it does not know ID 00 c8 60. > > IIRC garbage should be sent only at the time command is transferred so > > only one byte of garbage should be received. Also the garbage tends to > > be the last state of the data output - all 0 or all 1. > > So it seems using DMA for all transfers including 1-byte commands > > results in (some?) received data getting an extra 00 prefix. > > > > > > I also managed to lock up the controller completely since there is > > some error passing the SPI speed somewhere :( > > > > [ 1352.977530] spidev spi1.0: setup mode 0, 8 bits/w, 80000000 Hz max --> > > 0 [ 1352.977540] spidev spi1.0: spi mode 0 > > [ 1352.977576] spidev spi1.0: setup mode 0, 8 bits/w, 80000000 Hz max --> > > 0 [ 1352.977582] spidev spi1.0: msb first > > [ 1352.977614] spidev spi1.0: setup mode 0, 8 bits/w, 80000000 Hz max --> > > 0 [ 1352.977620] spidev spi1.0: 0 bits per word > > [ 1352.977652] spidev spi1.0: setup mode 0, 8 bits/w, 2690588672 Hz max > > --> 0 [ 1352.977726] spi_master spi1: s3c64xx_spi_config: clk_from_cmu 1 > > src_clk sclk_spi1 mode bpw 8 > > [ 1352.977753] spi_master spi1: spi1.0 s3c64xx_spi_transfer_one: xfer > > bpw 8 speed -1604378624 > > [ 1352.977760] spi_master spi1: s3c64xx_spi_config: clk_from_cmu 1 > > src_clk sclk_spi1 mode bpw 8 > > [ 1352.977781] spi_master spi1: spi1.0 s3c64xx_spi_transfer_one: using > > dma [ 1352.977797] dma-pl330 121b0000.pdma: setting up request on thread > > 1 > > Hmm, on a second thought it probably works as expected more or less. > > The nonsensical value was passed from application and there is no > guard against that. > > Since I don't do PIO the controller remains locked up indefinitely. I have to admit, I don't quite understand the above. I also don't quite know what your spidev test does. Can you possibly just bind a regular SPI NOR driver and run mtdtests to see if it is stable ? -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
