Re: [BUG] mtd: cfi_cmdset_0002: write regression since v4.17-rc1
From: Ahmad Fatoum <a.fatoum@pengutronix.de>
Date: 2022-02-14 16:23:16
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lkml, regressions
Hello Tokunori-san, On 13.02.22 17:47, Tokunori Ikegami wrote:
Hi Ahmad-san, Thanks for your confirmations. Sorry for late to reply.
No worries. I appreciate you taking the time.
Could you please try the patch attached to disable the chip_good() change as before? I think this should work for S29GL964N since the chip_ready() is used and works as mentioned.
yes, this resolves my issue: Tested-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
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Doesn't seem to be a buffered write issue here though as the writes did work fine before dfeae1073583. Any other ideas?At first I thought the issue is possible to be resolved by using the word write instead of the buffered writes. Now I am thinking to disable the changes dfeae1073583 partially with any condition if possible.What seems to work for me is checking if chip_good or chip_ready and map_word is equal to 0xFF. I can't justify why this is ok though. (Worst case bus is floating at this point of time and Hi-Z is read as 0xff on CPU data lines...)Sorry I am not sure about this. I thought the chip_ready() itself is correct as implemented as the data sheet in the past. But it did not work correctly so changed to use chip_good() instead as it is also correct.
What exactly in the datasheet makes you believe chip_good is not appropriate? Cheers, Ahmad -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |