Hello Jan, The flash on our board is Winbond W25Q128JV.
Best Regards, Le Jin -----Original Message----- From: Kiszka, Jan (CT RDA IOT SES-DE) <[email protected]> Sent: Monday, August 24, 2020 8:49 PM To: Vignesh Raghavendra <[email protected]>; Tudor Ambarus <[email protected]>; Mark Brown <[email protected]>; Jin, Le (RC-CN DI FA R&D SW) <[email protected]> Cc: Boris Brezillon <[email protected]>; Ramuthevar Vadivel Murugan <[email protected]>; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected] Subject: Re: [RESEND PATCH v3 5/8] mtd: spi-nor: cadence-quadspi: Handle probe deferral while requesting DMA channel On 24.08.20 13:45, Vignesh Raghavendra wrote: > > > On 8/22/20 11:35 PM, Jan Kiszka wrote: >> On 01.06.20 09:04, Vignesh Raghavendra wrote: >>> dma_request_chan_by_mask() can throw EPROBE_DEFER if DMA provider is >>> not yet probed. Currently driver just falls back to using PIO mode >>> (which is less efficient) in this case. Instead return probe >>> deferral error as is so that driver will be re probed once DMA >>> provider is available. >>> >>> Signed-off-by: Vignesh Raghavendra <[email protected]> >>> Reviewed-by: Tudor Ambarus <[email protected]> >>> --- > [...] >>> >>> static const struct spi_nor_controller_ops cqspi_controller_ops = { >>> @@ -1269,8 +1274,11 @@ static int cqspi_setup_flash(struct cqspi_st *cqspi, >>> struct device_node *np) >>> dev_dbg(nor->dev, "using direct mode for %s\n", >>> mtd->name); >>> >>> - if (!cqspi->rx_chan) >>> - cqspi_request_mmap_dma(cqspi); >>> + if (!cqspi->rx_chan) { >>> + ret = cqspi_request_mmap_dma(cqspi); >>> + if (ret == -EPROBE_DEFER) >>> + goto err; >>> + } >>> } >>> } >>> >>> >> >> This seem to break reading the SPI flash on our IOT2050 [1] (didn't >> test the eval board yet). >> >> Without that commit, read happens via PIO, and that works. With the >> commit, the pattern >> >> with open("out.bin", "wb") as out: >> pos = 0 >> while pos < 2: >> with open("/dev/mtd0", "rb") as mtd: >> mtd.seek(pos * 0x10000) >> out.write(mtd.read(0x10000)) >> pos += 1 >> >> gives the wrong result for the second block while > > Interesting... Could you please explain wrong result? Is the data move > around or completely garbage? It looks like some stripes contain data from other parts of the flash or kernel RAM. It's not just garbage, there are readable strings included. > > Does this fail even on AM654 EVM? Could you share full script for me > to test locally? The scripts are complete (python). Just binary-diff the outputs. I'll try on the EVM later. > > What is the flash on the board? Le, could you answer that more precisely than I could? Thanks, Jan > >> >> with open("out2.bin", "wb") as out: >> with open("/dev/mtd0", "rb") as mtd: >> out.write(mtd.read(0x20000)) >> >> (or "mtd_debug read") is fine. >> >> What could be the reason? Our DTBs and k3-am654-base-board.dtb had >> some deviations /wrt the ospi node, but aligning ours to the base >> board made no difference. >> >> Jan >> >> [1] https://github.com/siemens/linux/commits/jan/iot2050 >> -- Siemens AG, Corporate Technology, CT RDA IOT SES-DE Corporate Competence Center Embedded Linux
