mx6: Disable Power Down Bit of watchdog
On a mx6qsabresd revision C board with rev1.2 mx6q, the system gets resetted
and it is not able to reach the Linux prompt.
Comparing the watchdog behaviour on a revB versus revC board:
- On a mx6qsabresd revB:
U-Boot > reset
resetting ...
U-Boot 2013.01-10524-g432a3aa-dirty (Feb 07 2013 - 13:34:46)
CPU: Freescale i.MX6Q rev1.1 at 792 MHz
Reset cause: WDOG
...
- On a mx6qsabresd revC:
U-Boot > reset
resetting ...
U-Boot 2013.01-10524-g432a3aa-dirty (Feb 07 2013 - 13:34:46)
CPU: Freescale i.MX6Q rev1.1 at 792 MHz
Reset cause: POR
So due to revC POR/watchdog circuitry whenever a watchdog occurs, it causes a POR.
Clearing the PDE - Power Down Enable bit of WMCR registers fixes the problem and
is also safe for all mx6 boards.
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Otavio Salvador <otavio@ossystems.com.br>
Acked-by: Stefano Babic <sbabic@denx.de>
2 files changed