mtd: CFI cmdset_0002: enable erase-suspend-program

Erase-suspend for writing is required to avoid blocking applications
that wish to write some data (to a NOR block other than the one being
erased). Particularly, it solves some huge delays that an application
(which writes to a UBIFS) will experience if UBI attaches to empty NOR
flash. In this case the UBI background thread will erase a lot of blocks
and the application can be blocked for minutes because of the "MTD/CFI
chip lock".

This feature has been disabled for years. Maybe this was because the old
code turned it on for erase-suspend read-only chips also
(cfip->EraseSuspend & 0x1). This is wrong and corrected now.

This patch was tweaked by Norbert van Bolhuis.

Signed-off-by: Norbert van Bolhuis <nvbolhuis@aimvalley.nl>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
This commit is contained in:
Joakim Tjernlund 2009-11-19 12:01:58 +01:00 committed by David Woodhouse
parent c1317f7163
commit 2695eab964

View File

@ -490,10 +490,6 @@ static struct mtd_info *cfi_amdstd_setup(struct mtd_info *mtd)
}
#endif
/* FIXME: erase-suspend-program is broken. See
http://lists.infradead.org/pipermail/linux-mtd/2003-December/009001.html */
printk(KERN_NOTICE "cfi_cmdset_0002: Disabling erase-suspend-program due to code brokenness.\n");
__module_get(THIS_MODULE);
return mtd;
@ -589,15 +585,9 @@ static int get_chip(struct map_info *map, struct flchip *chip, unsigned long adr
return 0;
case FL_ERASING:
if (mode == FL_WRITING) /* FIXME: Erase-suspend-program appears broken. */
goto sleep;
if (!( mode == FL_READY
|| mode == FL_POINT
|| !cfip
|| (mode == FL_WRITING && (cfip->EraseSuspend & 0x2))
|| (mode == FL_WRITING && (cfip->EraseSuspend & 0x1)
)))
if (!cfip || !(cfip->EraseSuspend & (0x1|0x2)) ||
!(mode == FL_READY || mode == FL_POINT ||
(mode == FL_WRITING && (cfip->EraseSuspend & 0x2))))
goto sleep;
/* We could check to see if we're trying to access the sector