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@xxxxxxxxxxxx> 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.
