Thread (17 messages) 17 messages, 3 authors, 2022-03-08

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
Also in: 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>
quoted
quoted
quoted
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 |
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help