Hi, On Fri, May 1, 2015 at 9:05 AM, Michal Suchanek <[email protected]> wrote: > On 1 May 2015 at 01:13, Marek Vasut <[email protected]> wrote: >> On Thursday, April 30, 2015 at 11:13:12 PM, Michal Suchanek wrote: >>> The sector size of the flash memory is unclear from datasheet or may >>> possibly vary between chips so add a flag to always use 4k blocks. >>> >>> Currently 4k blocks are always used when possible but in the future >>> somebody might want to do some optimizations with sector erase. >>> >>> Signed-off-by: Michal Suchanek <[email protected]> >> >> I _think_ you might be able to determine the size, no ? >> >> One way is to ask the vendor, but you can also try something like: >> 1) erase the whole SPI NOR >> 2) overwrite it with zeroes (or ones ? I think it should be all ones after >> erasing). >> 3) Erase sector 0 >> 4) Read some 128 KiB back >> 5) Observe what is the difference. >> > > I can determine it for this particular chip. However, when the vendor > datasheet says the block is 64/32K it might mean that chips with this > ID can have either block size. > > It's a value that we don't use anyway so I just mark it as unknown > here for future reference.
It will be used if MTD_SPI_NOR_USE_4K_SECTORS is unset, so you should add some code to properly handle that case. Also I'd suggest switching the order of 2 and 3, so you add the flag handling first and then add support for a flash chip with this issue. Regards Jonas -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
