Messages in this thread | | | Subject | Re: [PATCH 1/2] dt-bindings: watchdog: Add arm,smc-wdt watchdog arm,smc-wdt compatible | From | Xingyu Chen <> | Date | Fri, 21 Feb 2020 23:36:01 +0800 |
| |
Hi, Evan
Because the ATF does not define standard wdt index, each vendor defines its own index. So I don't think that the current driver[0] can fully cover my usecases. As discussed in your previous email, the meson wdt driver [1] can use the arm_smccc instead of meson_sm_call.
[0]: https://patchwork.kernel.org/patch/11395579/ [1]: https://patchwork.kernel.org/patch/11331271/
Best Regards
On 2020/2/20 14:41, Evan Benn wrote: > Dear Xingyu, > > Could this driver also cover your usecase? I am not familiar with > meson, but it seems like the meson calls could > be replaced with arm_smccc calls. Then this driver will cover both > chips. I am not sure if your firmware is upstream > somewhere, but this might be adapted; > https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/3405 > > Thanks > > > On Thu, Feb 20, 2020 at 10:20 AM Guenter Roeck <linux@roeck-us.net> wrote: >> On Wed, Feb 19, 2020 at 03:04:54PM -0800, Julius Werner wrote: >>>> You are not the first 'watchdog in firmware accessed via an SMC call'. >>>> Is there some more detail about what implementation this is? Part of >>>> TF-A? Defined by some spec (I can dream)? >>> This is just some random implementation written by me because we >>> needed one. I would like it to be the new generic implementation, but >>> it sounds like people here prefer the naming to be MediaTek specific >>> (at least for now). The other SMC watchdog we're aware of is >>> imx_sc_wdt but unfortunately that seems to hardcode platform-specific >> There is one more pending, for Meson SMC. >> >> https://patchwork.kernel.org/project/linux-watchdog/list/?series=227733 >> >> Unfortunately it uses Meson firmware API functions, though it has pretty >> much the same functionality since those ultimately end up calling >> arm_smccc_smc(). >> >> Guenter >> >>> details in the interface (at least in the pretimeout SMC) so we can't >>> just expand that. With this driver I tried to directly wrap the kernel >>> watchdog interface so it should be platform-agnostic and possible to >>> expand this driver to other platforms later if desired. The SMC >>> function ID would still always have to be platform-specific, >>> unfortunately (but we could pass it in through the device tree), since >>> the Arm SMC spec doesn't really leave any room for OS-generic SMCs >>> like this. > .
| |