On Wed, Oct 31, 2018 at 7:22 AM Jagan Teki <ja...@amarulasolutions.com> wrote: > > On Wed, Oct 31, 2018 at 1:40 AM Simon Goldschmidt > <simon.k.r.goldschm...@gmail.com> wrote: > > > > When the device tree is missing a correct spi slave description below > > the bus (compatible "spi-flash" or spi-max-frequency are missing), > > the 'set_speed' callback can be called with 'speed' == 0 Hz. > > At least with cadence qspi, this leads to a division by zero. > > > > Prevent this by initializing speed to 100 kHz in this case (same > > fallback value as is done in 'dm_spi_claim_bus') and issue a warning > > to console. > > Why can't driver plat->frequency in cadence driver initialize 100KH? > plat->frequency = fdtdec_get_int(blob, node, "spi-max-frequency", 100000)
I'm not sure I understand. The cadence driver initializes its 'plat->max_hz' from "spi-max-frequency" property and defaults to 500 kHz. No problem there. However, the problem I want to solve is if someone puts a flash chip below there which has compatible != "spi-flash", they will get a hard fault which is hard to debug. This is because the node is not parsed because of the wrong compatible string (even if there is an "spi-max-frequency" property) and thus, "sf probe" tries to continue with 0 Hz. And this can happen easily when porting device trees from Linux as there, the boards have compatible "n25q00" etc. instead of "spi-flash", which is U-Boot specific (sadly). This patch is not required to make valid U-Boot devicetrees work, it is meant to get better error handling for devicetrees ported from Linux. An even better fix would be for U-Boot not to require the compatible = "spi-flash" string but just work correctly with Linux device trees, but that's not within my possibilities right now :-( Simon _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
