From: Bjorn Andersson <bjorn.andersson@linaro.org>
To: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Rob Herring <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Ohad Ben-Cohen <ohad@wizery.com>,
linux-arm-msm <linux-arm-msm@vger.kernel.org>,
devicetree@vger.kernel.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-remoteproc <linux-remoteproc@vger.kernel.org>,
Sibi Sankar <sibis@codeaurora.org>,
Rishabh Bhatnagar <rishabhb@codeaurora.org>
Subject: Re: [PATCH v2 7/8] remoteproc: qcom: q6v5: Add common panic handler
Date: Thu, 23 Jan 2020 09:15:24 -0800 [thread overview]
Message-ID: <20200123171524.GV1511@yoga> (raw)
In-Reply-To: <CANLsYkx-C9U4W3R3Xo6t3BJBM4UK_i3zuwzhnXMMEQ0-ur+8Kg@mail.gmail.com>
On Thu 23 Jan 09:01 PST 2020, Mathieu Poirier wrote:
> On Wed, 22 Jan 2020 at 12:40, Bjorn Andersson
> <bjorn.andersson@linaro.org> wrote:
> >
> > On Fri 10 Jan 13:28 PST 2020, Mathieu Poirier wrote:
> >
> > > On Thu, Dec 26, 2019 at 09:32:14PM -0800, Bjorn Andersson wrote:
> > > > Add a common panic handler that invokes a stop request and sleep enough
> > > > to let the remoteproc flush it's caches etc in order to aid post mortem
> > > > debugging.
> > > >
> > > > Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> > > > ---
> > > >
> > > > Changes since v1:
> > > > - None
> > > >
> > > > drivers/remoteproc/qcom_q6v5.c | 19 +++++++++++++++++++
> > > > drivers/remoteproc/qcom_q6v5.h | 1 +
> > > > 2 files changed, 20 insertions(+)
> > > >
> > > > diff --git a/drivers/remoteproc/qcom_q6v5.c b/drivers/remoteproc/qcom_q6v5.c
> > > > index cb0f4a0be032..17167c980e02 100644
> > > > --- a/drivers/remoteproc/qcom_q6v5.c
> > > > +++ b/drivers/remoteproc/qcom_q6v5.c
> > > > @@ -6,6 +6,7 @@
> > > > * Copyright (C) 2014 Sony Mobile Communications AB
> > > > * Copyright (c) 2012-2013, The Linux Foundation. All rights reserved.
> > > > */
> > > > +#include <linux/delay.h>
> > > > #include <linux/kernel.h>
> > > > #include <linux/platform_device.h>
> > > > #include <linux/interrupt.h>
> > > > @@ -15,6 +16,8 @@
> > > > #include <linux/remoteproc.h>
> > > > #include "qcom_q6v5.h"
> > > >
> > > > +#define Q6V5_PANIC_DELAY_MS 200
> > > > +
> > > > /**
> > > > * qcom_q6v5_prepare() - reinitialize the qcom_q6v5 context before start
> > > > * @q6v5: reference to qcom_q6v5 context to be reinitialized
> > > > @@ -162,6 +165,22 @@ int qcom_q6v5_request_stop(struct qcom_q6v5 *q6v5)
> > > > }
> > > > EXPORT_SYMBOL_GPL(qcom_q6v5_request_stop);
> > > >
> > > > +/**
> > > > + * qcom_q6v5_panic() - panic handler to invoke a stop on the remote
> > > > + * @q6v5: reference to qcom_q6v5 context
> > > > + *
> > > > + * Set the stop bit and sleep in order to allow the remote processor to flush
> > > > + * its caches etc for post mortem debugging.
> > > > + */
> > > > +void qcom_q6v5_panic(struct qcom_q6v5 *q6v5)
> > > > +{
> > > > + qcom_smem_state_update_bits(q6v5->state,
> > > > + BIT(q6v5->stop_bit), BIT(q6v5->stop_bit));
> > > > +
> > > > + mdelay(Q6V5_PANIC_DELAY_MS);
> > >
> > > I really wonder if the delay should be part of the remoteproc core and
> > > configurable via device tree. Wanting the remote processor to flush its caches
> > > is likely something other vendors will want when dealing with a kernel panic.
> > > It would be nice to see if other people have an opinion on this topic. If not
> > > then we can keep the delay here and move it to the core if need be.
> > >
> >
> > I gave this some more thought and what we're trying to achieve is to
> > signal the remote processors about the panic and then give them time to
> > react, but per the proposal (and Qualcomm downstream iirc) we will do
> > this for each remote processor, one by one.
> >
> > So in the typical case of a Qualcomm platform with 4-5 remoteprocs we'll
> > end up giving the first one a whole second to react and the last one
> > "only" 200ms.
> >
> > Moving the delay to the core by iterating over rproc_list calling
> > panic() and then delaying would be cleaner imo.
>
> I agree.
>
> >
> > It might be nice to make this configurable in DT, but I agree that it
> > would be nice to hear from others if this would be useful.
>
> I think the delay has to be configurable via DT if we move this to the
> core. The binding can be optional and default to 200ms if not
> present.
>
How about I make the panic() return the required delay and then we let
the core sleep for MAX() of the returned durations? That way the default
is still a property of the remoteproc drivers - and 200ms seems rather
arbitrary to put in the core, even as a default.
Regards,
Bjorn
next prev parent reply other threads:[~2020-01-23 17:15 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-27 5:32 [PATCH v2 0/8] remoteproc: qcom: post mortem debug support Bjorn Andersson
2019-12-27 5:32 ` [PATCH v2 1/8] dt-bindings: remoteproc: Add Qualcomm PIL info binding Bjorn Andersson
2020-01-04 21:38 ` Rob Herring
2020-01-04 22:17 ` Bjorn Andersson
2020-01-23 22:07 ` Rob Herring
2019-12-27 5:32 ` [PATCH v2 2/8] remoteproc: qcom: Introduce driver to store pil info in IMEM Bjorn Andersson
2020-01-10 21:18 ` Mathieu Poirier
2020-01-22 2:02 ` Bjorn Andersson
2020-01-22 19:04 ` Mathieu Poirier
2020-01-22 19:19 ` Bjorn Andersson
2020-01-22 22:56 ` rishabhb
2020-01-22 23:08 ` Bjorn Andersson
2020-01-22 23:58 ` rishabhb
2020-01-23 5:38 ` Bjorn Andersson
2019-12-27 5:32 ` [PATCH v2 3/8] remoteproc: qcom: Update IMEM PIL info on load Bjorn Andersson
2020-01-10 21:19 ` Mathieu Poirier
2019-12-27 5:32 ` [PATCH v2 4/8] arm64: dts: qcom: qcs404: Add IMEM and PIL info region Bjorn Andersson
2019-12-27 5:32 ` [PATCH v2 5/8] arm64: dts: qcom: sdm845: " Bjorn Andersson
2019-12-27 5:32 ` [PATCH v2 6/8] remoteproc: Introduce "panic" callback in ops Bjorn Andersson
2020-01-10 21:23 ` Mathieu Poirier
2020-01-30 10:07 ` Arnaud POULIQUEN
2019-12-27 5:32 ` [PATCH v2 7/8] remoteproc: qcom: q6v5: Add common panic handler Bjorn Andersson
2020-01-10 21:28 ` Mathieu Poirier
2020-01-22 19:39 ` Bjorn Andersson
2020-01-23 17:01 ` Mathieu Poirier
2020-01-23 17:15 ` Bjorn Andersson [this message]
2020-01-23 17:49 ` Arnaud POULIQUEN
2020-01-24 18:44 ` Mathieu Poirier
2020-01-27 9:46 ` Arnaud POULIQUEN
2020-01-29 20:15 ` Mathieu Poirier
2020-01-30 10:00 ` Arnaud POULIQUEN
2019-12-27 5:32 ` [PATCH v2 8/8] remoteproc: qcom: Introduce panic handler for PAS and ADSP Bjorn Andersson
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