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Date: Thu, 4 Aug 2016 11:44:36 +0200 From: loic pallardy <loic.pallardy@...com> To: Bjorn Andersson <bjorn.andersson@...aro.org> CC: <linux-remoteproc@...r.kernel.org>, Ohad Ben-Cohen <ohad@...ery.com>, <linux-kernel@...r.kernel.org>, Lee Jones <lee.jones@...aro.org> Subject: Re: [PATCH 1/4] remoteproc: Introduce always-on flag On 08/04/2016 12:02 AM, Bjorn Andersson wrote: > On Tue 02 Aug 08:17 PDT 2016, loic pallardy wrote: > >> Hi Bjorn, >> >> On 08/01/2016 08:58 PM, Bjorn Andersson wrote: >>> Introduce an "always-on" flag on rprocs to make it possible to flag >>> remote processors without vdevs to automatically boot once the firmware >>> is found. >>> >> Should this flag rather be named "auto-boot"? From my pov, "always-on" means >> coprocessor can't be shutdown. >> > > I saw it from the view of the remoteproc driver, in which case it's > always-on. But I'm fine with naming it "auto-boot" instead. > > [..] >>> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c > [..] >>> @@ -978,11 +982,16 @@ static int rproc_add_virtio_devices(struct rproc *rproc) >>> int rproc_trigger_recovery(struct rproc *rproc) >>> { >>> struct rproc_vdev *rvdev, *rvtmp; >>> + int ret; >>> >>> dev_err(&rproc->dev, "recovering %s\n", rproc->name); >>> >>> init_completion(&rproc->crash_comp); >>> >>> + /* shut down the remote */ >>> + /* TODO: make sure this works with rproc->power > 1 */ >>> + rproc_shutdown(rproc); >>> + >>> /* clean up remote vdev entries */ >>> list_for_each_entry_safe(rvdev, rvtmp, &rproc->rvdevs, node) >>> rproc_remove_virtio_dev(rvdev); >>> @@ -993,7 +1002,17 @@ int rproc_trigger_recovery(struct rproc *rproc) >>> /* Free the copy of the resource table */ >>> kfree(rproc->cached_table); >>> >>> - return rproc_add_virtio_devices(rproc); >>> + ret = rproc_add_virtio_devices(rproc); >>> + if (ret) >>> + return ret; >>> + >>> + /* >>> + * boot the remote processor up again, waiting for the async fw load to >>> + * finish >>> + */ >>> + rproc_boot(rproc); >> You are changing current behavior by forcing rproc boot whatever >> "always-on". Moreover coprocessor already rebooted by >> rproc_add_virtio_device if "always-on" flag is set, doesn't it? >> If yes, rproc->power will be equal to 2 and rproc_shutdown call will failed >> as this second rproc_boot call is unknown from customer pov. >> > > rproc_add_virtio_devices() does no longer call rproc_boot(), this patch > moves that call. So for always-on rprocs "power" will go 1 -> 0 -> 1 in > this function. > > What does change is that for a non-always-on case. > > If we have 1 client that has requested rproc_boot() then the current > implementation will bring "power" down to 1 and we will wait until the > client for some reason calls rproc_shutdown(). After that we might boot > the system again, if there are any vdevs in the resource table. > > Here we will bring "power" from 1 -> 0 -> 1, without regarding who's > holding references. I'm fine with the final sequence in which only rproc_shutdown and rproc_boot are called (with patch 3 modifications). But having a look only to this patch, we have the following function call: rproc_trigger_recovery |__ rproc_shutdown --> power from 1 -> 0 |__ rproc_add_virtio_devices |__ rproc_fw_config_virtio |__ (if always_on == 1) rproc_boot_nowait --> power from 0 --> 1 |__ rproc_boot if always_on == 1 power from 1 --> 2 else power from 0 --> 1 on this patch rproc_boot should be called only is always_on flag is not set. With patch 3, call to rproc_add_virtio_devices is suppressed and behavior is ok. Regards, Loic > >>> + >>> + return 0; >>> } > > Regards, > Bjorn >
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