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x86_64-pc-linux-gnu) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190124_083409_007732_F64C93A3 X-CRM114-Status: GOOD ( 18.03 ) X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Stefan Roese , Richard Weinberger , stable@vger.kernel.org, Marek Vasut , linux-mtd@lists.infradead.org, Miquel Raynal , Brian Norris , David Woodhouse Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org On Thu, 24 Jan 2019 17:16:37 +0100 Emil Lenngren wrote: > Hi, > > Den tors 24 jan. 2019 kl 16:28 skrev Stefan Roese : > > > > On 24.01.19 15:20, Boris Brezillon wrote: > > > Looks like PROGRAM LOAD (AKA write cache) does not necessarily reset > > > the cache content to 0xFF (depends on vendor implementation), so we > > > must fill the page cache entirely even if we only want to program the > > > data portion of the page, otherwise we might corrupt the BBM or user > > > data previously programmed in OOB area. > > > > > > Fixes: 7529df465248 ("mtd: nand: Add core infrastructure to support SPI NANDs") > > > Reported-by: Stefan Roese > > > Cc: > > > Signed-off-by: Boris Brezillon > > > > Works fine (limited testing only yet), so: > > > > Tested-by: Stefan Roese > > Reviewed-by: Stefan Roese > > > > Thanks, > > Stefan > > > > Can this quirk be made vendor specific? We can make it vendor specific, as long as it's an opt-in thing. This way, the default behavior is the safest one, and only when we know a chip does reset the cache content on a PROGRAM LOAD time can we add this flag. > It seems a waste of SPI > transfer cycles to write 0xff to the whole OOB area when we only want > to program the data area if the chip doesn't need this quirk. > For which logic is this needed anyway? According to the GigaDevice > datasheet, if a Program Load is followed by Program Execute, > "uninitialized" bytes will be set to 0xff, which is the flow that is > used by spinand core. Except you're not guaranteed that the controller can fill the page in a single spi_mem_exec_op() call (because of FIFO size limitations), so you might have one PROGRAM LOAD followed by several PROGRAM RANDOM LOAD. I guess most manufacturers reset the cache content at PROGRAM LOAD time, but GigaDevice does not. > > /Emil ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/