Re: [PATCH v3 0/3] Add support for WDIOF_CARDRESET on TI AM65x

[Guenter Roeck]

On 7/13/23 02:51, huaqian.li@xxxxxxxxxxx wrote:
> From: Li Hua Qian <huaqian.li@xxxxxxxxxxx>
>
> The watchdog hardware of TI AM65X platform does not support
> WDIOF_CARDRESET feature, add a reserved memory to save the watchdog
> reset cause, to know if the board reboot is due to a watchdog reset.

One thing I keep wondering about: What prevents the Linux kernel from
treating the special memory area like normal memory ? I would have expected
some usage note, such as that the memory area must be reported as reserved
to the kernel, but I don't see anything like that.

Guenter

> Changes in v3:
> - Add memory-region back for the reserved memory, and remove reserved
>    memory from the watchdog IO address space.
> - Add changelog.
> - Link to v2:
>    https://lore.kernel.org/linux-watchdog/20230711091713.1113010-1-huaqian.li@xxxxxxxxxxx
>
> Changes in v2:
> - Remove memory-region and memory-size properties, and bind the reserved
>    memory to watchdog IO address space.
> - Remove the unnecessary rti_wdt_ioctl.
> - Fix the mail list
> - Link to v1:
>    https://lore.kernel.org/all/3137d87e56ef75ba0b8a923d407b2fecace6ccbd.camel@xxxxxxxxxxx/
>    v1 had a wrong mail list at the beginning, and the mail thread was
>    messed up.
>
> Li Hua Qian (3):
>    dt-bindings: watchdog: ti,rti-wdt: Add support for WDIOF_CARDRESET
>    arm64: dts: ti: Add reserved memory for watchdog
>    watchdog:rit_wdt: Add support for WDIOF_CARDRESET
>
>   .../bindings/watchdog/ti,rti-wdt.yaml         | 12 +++++
>   .../boot/dts/ti/k3-am65-iot2050-common.dtsi   | 10 ++++
>   drivers/watchdog/rti_wdt.c                    | 51 +++++++++++++++++++
>   3 files changed, 73 insertions(+)