[PATCH 3.16 208/366] mtd: cfi: cmdset_0001: Do not allow read/write to suspend erase block.

Ben Hutchings
2018-10-14T23:30:47Z

From: Joakim Tjernlund <joakim.tjernlund@transmode.se>

commit 6510bbc88e3258631831ade49033537081950605 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.

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_0001.c | 16 +++++++++++-----
include/linux/mtd/flashchip.h | 1 +
2 files changed, 12 insertions(+), 5 deletions(-)

--- a/drivers/mtd/chips/cfi_cmdset_0001.c
+++ b/drivers/mtd/chips/cfi_cmdset_0001.c
@@ -825,21 +825,25 @@ static int chip_ready (struct map_info *
(mode == FL_WRITING && (cfip->SuspendCmdSupport & 1))))
goto sleep;

+ /* 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 */
- map_write(map, CMD(0xB0), adr);
+ map_write(map, CMD(0xB0), chip->in_progress_block_addr);

/* If the flash has finished erasing, then 'erase suspend'
* appears to make some (28F320) flash devices switch to
* 'read' mode. Make sure that we switch to 'read status'
* mode so we get the right data. --rmk
*/
- map_write(map, CMD(0x70), adr);
+ map_write(map, CMD(0x70), chip->in_progress_block_addr);
chip->oldstate = FL_ERASING;
chip->state = FL_ERASE_SUSPENDING;
chip->erase_suspended = 1;
for (;;) {
- status = map_read(map, adr);
+ status = map_read(map, chip->in_progress_block_addr);
if (map_word_andequal(map, status, status_OK, status_OK))
break;

@@ -1035,8 +1039,8 @@ static void put_chip(struct map_info *ma
sending the 0x70 (Read Status) command to an erasing
chip and expecting it to be ignored, that's what we
do. */
- map_write(map, CMD(0xd0), adr);
- map_write(map, CMD(0x70), adr);
+ map_write(map, CMD(0xd0), chip->in_progress_block_addr);
+ map_write(map, CMD(0x70), chip->in_progress_block_addr);
chip->oldstate = FL_READY;
chip->state = FL_ERASING;
break;
@@ -1927,6 +1931,8 @@ static int __xipram do_erase_oneblock(st
map_write(map, CMD(0xD0), adr);
chip->state = FL_ERASING;
chip->erase_suspended = 0;
+ chip->in_progress_block_addr = adr;
+ chip->in_progress_block_mask = ~(len - 1);

ret = INVAL_CACHE_AND_WAIT(map, chip, adr,
adr, len,
--- a/include/linux/mtd/flashchip.h
+++ b/include/linux/mtd/flashchip.h
@@ -85,6 +85,7 @@ struct flchip {
unsigned int write_suspended:1;
unsigned int erase_suspended:1;
unsigned long in_progress_block_addr;
+ unsigned long in_progress_block_mask;

struct mutex mutex;
wait_queue_head_t wq; /* Wait on here when we're waiting for the chip