MT7621 soc HW watchdog does not work?

suvine · April 23, 2021, 9:00am

I use MT7621 soc, enabled internal HW watchdog,but at watchdog time out ,the system does not reboot and hangs.Why ?
i use linux 4.4.198 source code,mt7621_wdt.c

suvine · April 23, 2021, 9:03am

openwrt version is 17.01

LGA1150 · April 23, 2021, 10:22am

What flash chip does your router have?

suvine · April 25, 2021, 2:05am

WINBOND-25q256JVFQ 32m spi nor

LGA1150 · April 25, 2021, 2:13am

You need to enable stateless 4-byte opcode on it.

suvine · April 25, 2021, 3:26am

Thank you for your reply.Is there any linux4.x code patch exist？we use linux 4.4.198 source code.or i'll porting to it.

LGA1150 · April 25, 2021, 7:09am

If you are sure all your routers don't use W25Q256FV, you can enable SPI_NOR_4B_OPCODES unconditionally.

github.com

gregkh/linux/blob/v4.4.198/drivers/mtd/spi-nor/spi-nor.c#L846


	{ "w25x32", INFO(0xef3016, 0, 64 * 1024,  64, SECT_4K) },
	{ "w25q32", INFO(0xef4016, 0, 64 * 1024,  64, SECT_4K) },
	{ "w25q32dw", INFO(0xef6016, 0, 64 * 1024,  64, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
	{ "w25x64", INFO(0xef3017, 0, 64 * 1024, 128, SECT_4K) },
	{ "w25q64", INFO(0xef4017, 0, 64 * 1024, 128, SECT_4K) },
	{ "w25q64dw", INFO(0xef6017, 0, 64 * 1024, 128, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
	{ "w25q128fw", INFO(0xef6018, 0, 64 * 1024, 256, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
	{ "w25q80", INFO(0xef5014, 0, 64 * 1024,  16, SECT_4K) },
	{ "w25q80bl", INFO(0xef4014, 0, 64 * 1024,  16, SECT_4K) },
	{ "w25q128", INFO(0xef4018, 0, 64 * 1024, 256, SECT_4K) },
	{ "w25q256", INFO(0xef4019, 0, 64 * 1024, 512, SECT_4K) },


	/* Catalyst / On Semiconductor -- non-JEDEC */
	{ "cat25c11", CAT25_INFO(  16, 8, 16, 1, SPI_NOR_NO_ERASE | SPI_NOR_NO_FR) },
	{ "cat25c03", CAT25_INFO(  32, 8, 16, 2, SPI_NOR_NO_ERASE | SPI_NOR_NO_FR) },
	{ "cat25c09", CAT25_INFO( 128, 8, 32, 2, SPI_NOR_NO_ERASE | SPI_NOR_NO_FR) },
	{ "cat25c17", CAT25_INFO( 256, 8, 32, 2, SPI_NOR_NO_ERASE | SPI_NOR_NO_FR) },
	{ "cat25128", CAT25_INFO(2048, 8, 64, 2, SPI_NOR_NO_ERASE | SPI_NOR_NO_FR) },
	{ },
};

suvine · April 25, 2021, 7:40am

SPI_NOR_4B_OPCODES is not define in this linux version code

LGA1150 · April 25, 2021, 9:50am

So you have to backport it..

suvine · April 26, 2021, 7:43am

I've porting this code to linux 4.4.198，but the system still not reboot and huang after HW watchdog time out。

LGA1150 · April 26, 2021, 10:16am

Try triggering a kernel panic to check if it reboots properly.
echo c > /proc/sysrq-trigger

suvine · April 29, 2021, 10:07am

reboot failed.hang

suvine · April 29, 2021, 10:12am

i add this code

and software reboot can become effective.but watchdog timeout still hang.

LGA1150 · April 29, 2021, 10:14am

That means the flash chip is still in stateful 4-byte mode. Your backport does not work.

suvine · April 29, 2021, 10:27am

so you mean the flash use 3-byte mode all the time.then watchdog timeout will reboot automatic ？

suvine · April 30, 2021, 1:54am

I changed to linux 4.14.206 source code which has the patch stateful 4-byte mode。
patch：0053-mtd-spi-nor-add-w25q256-3b-mode-switch、0054-mtd-spi-nor-w25q256-respect-default-mode
software reboot cmd is effective.but watchdog timeout still hang.I think the key problem is not spi nor flash。

LGA1150 · April 30, 2021, 2:03am

You still need to set SPI_NOR_4B_OPCODES

suvine · April 30, 2021, 2:17am

but mt7621 boot HW strapping is SPI 3-byte address mode.

suvine · April 30, 2021, 2:19am

anyhow i change HW spi nor flash into 16M,the watchdog still not work.

LGA1150 · April 30, 2021, 4:25am

SPI_NOR_4B_OPCODES is stateless and not a mode