[PATCH 3.16 210/366] mtd: cfi: cmdset_0002: Do not allow read/write to suspend erase block.

Ben Hutchings
2018-10-14T15:25:41Z

From: Joakim Tjernlund <joakim.tjernlund@infinera.com>

commit 7b70eb14392a7cf505f9b358d06c33b5af73d1e7 upstream.

Currently it is possible to read and/or write to suspend EB's.
Writing /dev/mtdX or /dev/mtdblockX from several processes may
break the flash state machine.

Taken from cfi_cmdset_0001 driver.

Signed-off-by: Joakim Tjernlund <joakim.tjernlund@infinera.com>
Reviewed-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/mtd/chips/cfi_cmdset_0002.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

--- a/drivers/mtd/chips/cfi_cmdset_0002.c
+++ b/drivers/mtd/chips/cfi_cmdset_0002.c
@@ -780,9 +780,10 @@ static int get_chip(struct map_info *map
(mode == FL_WRITING && (cfip->EraseSuspend & 0x2))))
goto sleep;

- /* We could check to see if we're trying to access the sector
- * that is currently being erased. However, no user will try
- * anything like that so we just wait for the timeout. */
+ /* Do not allow suspend iff read/write to EB address */
+ if ((adr & chip->in_progress_block_mask) ==
+ chip->in_progress_block_addr)
+ goto sleep;

/* Erase suspend */
/* It's harmless to issue the Erase-Suspend and Erase-Resume
@@ -1926,6 +1927,7 @@ static int __xipram do_erase_chip(struct
chip->state = FL_ERASING;
chip->erase_suspended = 0;
chip->in_progress_block_addr = adr;
+ chip->in_progress_block_mask = ~(map->size - 1);

INVALIDATE_CACHE_UDELAY(map, chip,
adr, map->size,
@@ -2015,6 +2017,7 @@ static int __xipram do_erase_oneblock(st
chip->state = FL_ERASING;
chip->erase_suspended = 0;
chip->in_progress_block_addr = adr;
+ chip->in_progress_block_mask = ~(len - 1);

INVALIDATE_CACHE_UDELAY(map, chip,
adr, len,