On 19/03/2020 12.25, Vignesh Raghavendra wrote:
Hi,
On 17/03/20 1:48 am, Rasmus Villemoes wrote:
I have a board for which doing "sf erase 0x100000 0x80000" consistently causes the external watchdog circuit to reset the board. Make sure to pet the watchdog during slow operations such as erasing or writing large areas of a spi nor flash.
Signed-off-by: Rasmus Villemoes rasmus.villemoes@prevas.dk
drivers/mtd/spi/spi-nor-core.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/mtd/spi/spi-nor-core.c b/drivers/mtd/spi/spi-nor-core.c index 4076646225..b7f7aa7b28 100644 --- a/drivers/mtd/spi/spi-nor-core.c +++ b/drivers/mtd/spi/spi-nor-core.c @@ -20,6 +20,7 @@ #include <linux/mtd/spi-nor.h> #include <spi-mem.h> #include <spi.h> +#include <watchdog.h>
#include "sf_internal.h"
@@ -399,6 +400,7 @@ static int spi_nor_ready(struct spi_nor *nor) { int sr, fsr;
- WATCHDOG_RESET();
Is it necessary to reset watchdog for every status register read? How small is the timeout? Resetting too often will impact performance depending on overhead of this call.
Is it not sufficient to reset watchdog once per page write (in spi_nor_write()) and once per sector erase (in spi_nor_erase())?
Probably, yes. I was a bit torn between putting the call here or in spi_nor_wait_till_ready(). That should do it once per erase/page write which should be fine (well, if the busy-looping for spi_nor_ready takes more than the watchdog timeout, the board will reset, but I don't think the flash is that bad).
I'll test that, but I just found out I'll need something in the read path as well. Reading 1MB works fine, reading 2MB resets:
[2020-03-19 12:31:11.923] => echo a ; sf read $loadaddr 0 0x100000 ; echo b [2020-03-19 12:31:32.724] a [2020-03-19 12:31:32.724] device 0 offset 0x0, size 0x100000 [2020-03-19 12:31:33.586] SF: 1048576 bytes @ 0x0 Read: OK [2020-03-19 12:31:33.586] b [2020-03-19 12:31:33.586] => echo a ; sf read $loadaddr 0 0x200000 ; echo b [2020-03-19 12:31:40.771] a [2020-03-19 12:31:40.771] device 0 offset 0x0, size 0x200000 [2020-03-19 12:31:42.666] [2020-03-19 12:31:42.666] U-Boot SPL 2020.01-00078-g058da1a-dirty (Mar 17 2020 - 16:27:58 +0000)
Rasmus