From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Return-Path: Date: Wed, 25 Mar 2020 11:57:46 -0600 From: Mathieu Poirier Subject: Re: [RFC 1/2] remoteproc: sysfs: authorize rproc shutdown when rproc is crashed Message-ID: <20200325175746.GA6227@xps15> References: <1583924072-20648-1-git-send-email-loic.pallardy@st.com> <1583924072-20648-2-git-send-email-loic.pallardy@st.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1583924072-20648-2-git-send-email-loic.pallardy@st.com> To: Loic Pallardy Cc: bjorn.andersson@linaro.org, ohad@wizery.com, linux-remoteproc@vger.kernel.org, linux-kernel@vger.kernel.org, arnaud.pouliquen@st.com, benjamin.gaignard@linaro.org, fabien.dessenne@st.com, s-anna@ti.com List-ID: Hi Loic, On Wed, Mar 11, 2020 at 11:54:31AM +0100, Loic Pallardy wrote: > When remoteproc recovery is disabled and rproc crashed, user space > client has no way to reboot co-processor except by a complete platform > reboot. > Indeed rproc_shutdown() is called by sysfs state_store() only is rproc > state is RPROC_RUNNING. > > This patch offers the possibility to shutdown the co-processor if > it is in RPROC_CRASHED state and so to restart properly co-processor > from sysfs interface. If recovery is disabled on an rproc the platform likely intended to have a hard reboot and as such we should not be concerned about this case. Where I think we have a problem, something that is asserted by looking at your 2 patches, is cases where rproc_trigger_recovery() fails. That leaves the system in a state where it can't be recovered, something the remoteproc core should not allow. > > Signed-off-by: Loic Pallardy > --- > drivers/remoteproc/remoteproc_core.c | 2 +- > drivers/remoteproc/remoteproc_sysfs.c | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c > index 097f33e4f1f3..7ac87a75cd1b 100644 > --- a/drivers/remoteproc/remoteproc_core.c > +++ b/drivers/remoteproc/remoteproc_core.c > @@ -1812,7 +1812,7 @@ void rproc_shutdown(struct rproc *rproc) > if (!atomic_dec_and_test(&rproc->power)) > goto out; > > - ret = rproc_stop(rproc, false); > + ret = rproc_stop(rproc, rproc->state == RPROC_CRASHED); Please add a comment that explains how we can be in rproc_shutdown() when the processor has crashed and point to rproc_trigger_recovery(). See below for more details. > if (ret) { > atomic_inc(&rproc->power); > goto out; > diff --git a/drivers/remoteproc/remoteproc_sysfs.c b/drivers/remoteproc/remoteproc_sysfs.c > index 7f8536b73295..1029458a4678 100644 > --- a/drivers/remoteproc/remoteproc_sysfs.c > +++ b/drivers/remoteproc/remoteproc_sysfs.c > @@ -101,7 +101,7 @@ static ssize_t state_store(struct device *dev, > if (ret) > dev_err(&rproc->dev, "Boot failed: %d\n", ret); > } else if (sysfs_streq(buf, "stop")) { > - if (rproc->state != RPROC_RUNNING) > + if (rproc->state != RPROC_RUNNING && rproc->state != RPROC_CRASHED) > return -EINVAL; Wouldn't it be better to just prevent the MCU to stay in a crashed state (when recovery is not disabled)? I like what you did in the next patch where the state of the MCU is set to RPROC_CRASHED in case of failure, so that we keep. I also think the hunk above is correct. All that is left is to call rproc_shutdown() directly in rproc_trigger_recovery() when something goes wrong. I would also add a dev_err() so that users have a clue of what happened. That would leave the system in a stable state without having to add intelligence to state_store(). Let me know that you think... Mathieu > > rproc_shutdown(rproc); > -- > 2.7.4 >