Re: [PATCH v2 0/2] Add a watchdog driver that uses ARM Secure Monitor Calls.

[Xingyu Chen <xingyu.chen@xxxxxxxxxxx>]

Hi,Evan

On 2020/4/11 23:06, Xingyu Chen wrote:
> Hi, Evan
>
> On 2020/4/3 14:04, Evan Benn wrote:
> > Apologies I forgot to add this note to my cover letter.
> >
> > Xingyu do you mind seeing if you can modify your ATF firmware to match 
> > this driver?
> > We can add a compatible or make other changes to suit you.
> Thanks for your patch [0],  I will test this patch on the meson-A1 
> platform, but It looks more
> convenient to be compatible with other platforms if using the compatible 
> strings to correlate
> platform differences include function ID and wdt_ops.
>
> [0]: https://patchwork.kernel.org/patch/11471829/

I have tested your patch on the meson-A1, but I use the compatible 
strings to correlate the following platform differences，it works normally.

static const struct smcwd_data smcwd_mtk_data = {
	.func_id = 0x82003d06,
	.ops     = &smcwd_ops,
}

static const struct smcwd_data smcwd_meson_data = {
	.func_id = 0x82000086,
	.ops     = &smcwd_timeleft_ops,
}

In addition, It looks more reasonable to use the "msec" as the unit of 
timeout parameter for the ATF fw interface with SMCWD_SET_TIMEOUT:

- The fw interface will compatible with the uboot generic watchdog 
interface at [0], and there is no need to convert timeout from msec
to sec.

- Some vendor's watchdog may be not support the "wdt_trigger_reset" 
reset operation, but they can use the method below to reset the system
by the watchdog right now.

watchdog_set_time(1);  //1ms
watchdog_enable();

[0]: 
https://gitlab.denx.de/u-boot/u-boot/-/blob/master/drivers/watchdog/wdt-uclass.c

Best Regards
> > Thanks
> >
> > On Fri, Apr 3, 2020 at 4:29 PM Evan Benn <evanbenn@xxxxxxxxxxxx 
> > <mailto:evanbenn@xxxxxxxxxxxx>> wrote:
> >
> >     This is currently supported in firmware deployed on oak, hana and
> >     elm mt8173
> >     chromebook devices. The kernel driver is written to be a generic SMC
> >     watchdog driver.
> >
> >     Arm Trusted Firmware upstreaming review:
> >     https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/3405
> >
> >     Patch to add oak, hana, elm device tree:
> >     https://lore.kernel.org/linux-arm-kernel/20200110073730.213789-1-hsinyi@xxxxxxxxxxxx/
> >     I would like to add the device tree support after the above patch is
> >     accepted.
> >
> >     Changes in v3:
> >     - Change name back to arm
> >     - Add optional get_timeleft op
> >     - change name to arm_smc_wdt
> >
> >     Changes in v2:
> >     - Change name arm > mt8173
> >     - use watchdog_stop_on_reboot
> >     - use watchdog_stop_on_unregister
> >     - use devm_watchdog_register_device
> >     - remove smcwd_shutdown, smcwd_remove
> >     - change error codes
> >
> >     Evan Benn (1):
> >       dt-bindings: watchdog: Add ARM smc wdt for mt8173 watchdog
> >
> >     Julius Werner (1):
> >       watchdog: Add new arm_smd_wdt watchdog driver
> >
> >      .../bindings/watchdog/arm-smc-wdt.yaml        |  30 +++
> >      MAINTAINERS                                   |   7 +
> >      arch/arm64/configs/defconfig                  |   1 +
> >      drivers/watchdog/Kconfig                      |  13 ++
> >      drivers/watchdog/Makefile                     |   1 +
> >      drivers/watchdog/arm_smc_wdt.c                | 181
> >     ++++++++++++++++++
> >      6 files changed, 233 insertions(+)
> >      create mode 100644
> >     Documentation/devicetree/bindings/watchdog/arm-smc-wdt.yaml
> >      create mode 100644 drivers/watchdog/arm_smc_wdt.c
> >
> >     -- 
> >     2.26.0.292.g33ef6b2f38-goog