From: Mathieu Poirier <mathieu.poirier@linaro.org>
To: Suman Anna <s-anna@ti.com>
Cc: Loic PALLARDY <loic.pallardy@st.com>,
"bjorn.andersson@linaro.org" <bjorn.andersson@linaro.org>,
"ohad@wizery.com" <ohad@wizery.com>,
"peng.fan@nxp.com" <peng.fan@nxp.com>,
Arnaud POULIQUEN <arnaud.pouliquen@st.com>,
Fabien DESSENNE <fabien.dessenne@st.com>,
"linux-remoteproc@vger.kernel.org"
<linux-remoteproc@vger.kernel.org>
Subject: Re: [PATCH v2 16/17] remoteproc: Correctly deal with MCU synchronisation when changing state
Date: Thu, 2 Apr 2020 14:42:31 -0600 [thread overview]
Message-ID: <20200402204231.GC9160@xps15> (raw)
In-Reply-To: <5223cca7-5409-a113-8a7f-9f6923231353@ti.com>
Hi Suman,
On Tue, Mar 31, 2020 at 05:35:58PM -0500, Suman Anna wrote:
> Hi Mathieu,
>
> On 3/30/20 6:49 PM, Mathieu Poirier wrote:
> > On Fri, Mar 27, 2020 at 02:04:36PM +0000, Loic PALLARDY wrote:
> >>
> >>
> >>> -----Original Message-----
> >>> From: Mathieu Poirier <mathieu.poirier@linaro.org>
> >>> Sent: mardi 24 mars 2020 22:46
> >>> To: bjorn.andersson@linaro.org
> >>> Cc: ohad@wizery.com; Loic PALLARDY <loic.pallardy@st.com>; s-
> >>> anna@ti.com; peng.fan@nxp.com; Arnaud POULIQUEN
> >>> <arnaud.pouliquen@st.com>; Fabien DESSENNE
> >>> <fabien.dessenne@st.com>; linux-remoteproc@vger.kernel.org
> >>> Subject: [PATCH v2 16/17] remoteproc: Correctly deal with MCU
> >>> synchronisation when changing state
> >>>
> >>> This patch deals with state changes when synchronising with an MCU. More
> >>> specifically it prevents the MCU from being started if it already has been
> >>> started by another entity. Similarly it prevents the AP from stopping the
> >>> MCU if it hasn't been given the capability by platform firmware.
> >>>
> >>> Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
> >>> ---
> >>> drivers/remoteproc/remoteproc_sysfs.c | 32
> >>> ++++++++++++++++++++++++++-
> >>> 1 file changed, 31 insertions(+), 1 deletion(-)
> >>>
> >>> diff --git a/drivers/remoteproc/remoteproc_sysfs.c
> >>> b/drivers/remoteproc/remoteproc_sysfs.c
> >>> index 4956577ad4b4..741a3c152b82 100644
> >>> --- a/drivers/remoteproc/remoteproc_sysfs.c
> >>> +++ b/drivers/remoteproc/remoteproc_sysfs.c
> >>> @@ -108,6 +108,29 @@ static ssize_t state_show(struct device *dev, struct
> >>> device_attribute *attr,
> >>> return sprintf(buf, "%s\n", rproc_state_string[state]);
> >>> }
> >>>
> >>> +static int rproc_can_shutdown(struct rproc *rproc)
> >>> +{
> >>> + /* The MCU is not running, obviously an invalid operation. */
> >>> + if (rproc->state != RPROC_RUNNING)
> >>> + return false;
> >>> +
> >>> + /*
> >>> + * The MCU is not running (see above) and the remoteproc core is
> >>> the
> >>> + * lifecycle manager, no problem calling for a shutdown.
> >>> + */
> >>> + if (!rproc_sync_with_mcu(rproc))
> >>> + return true;
> >>> +
> >>> + /*
> >>> + * The MCU has been loaded by another entity (see above) and the
> >>> + * platform code has _not_ given us the capability of stopping it.
> >>> + */
> >>> + if (!rproc->sync_ops->stop)
> >>> + return false;
> >>
> >> Test could be simplified
> >> if (rproc_sync_with_mcu(rproc)) && !rproc->sync_ops->stop)
> >> return false;
> >
> > I laid out the test individually on purpose. That way there is no coupling
> > between conditions, it is plane to see what is going on and remains maintainable
> > as we add new tests.
> >
> >>
> >>> +
> >>> + return true;
> >>> +}
> >>> +
> >>> /* Change remote processor state via sysfs */
> >>> static ssize_t state_store(struct device *dev,
> >>> struct device_attribute *attr,
> >>> @@ -120,11 +143,18 @@ static ssize_t state_store(struct device *dev,
> >>> if (rproc->state == RPROC_RUNNING)
> >>> return -EBUSY;
> >>>
> >>> + /*
> >>> + * In synchronisation mode, booting the MCU is the
> >>> + * responsibility of an external entity.
> >>> + */
> >>> + if (rproc_sync_with_mcu(rproc))
> >>> + return -EINVAL;
> >>> +
> >> I don't understand this restriction, simply because it is preventing to resynchronize with a
> >> coprocessor after a "stop".
>
> There's actually one more scenario even without "stop". If auto_boot is
> set to false, then rproc_actuate will never get called.
>
> >> In the following configuration which can be configuration for coprocessor with romed/flashed
> >> firmware (no reload needed):
> >> on_init = true
> >> after_stop = true
> >> after_crash = true
> >> Once you stop it via sysfs interface, you can't anymore restart/resync to it.
> >
> > Very true. The MCU will get restarted by another entity but the AP won't
> > synchronise with it. I need more time to think about the best way to deal with
> > this and may have to get back to you for further discussions.
> >
> >>
> >> I think it will be better to modify rproc_boot() to take into account rproc_sync_with_mcu()
> >> as below:
> >>
> >> int rproc_boot(struct rproc *rproc)
> >> {
> >> - const struct firmware *firmware_p;
> >> + const struct firmware *firmware_p = NULL;
> >> struct device *dev = &rproc->dev;
> >> int ret;
> >>
> >> if (!rproc) {
> >> pr_err("invalid rproc handle\n");
> >> return -EINVAL;
> >> }
> >>
> >> /* load firmware */
> >> - ret = request_firmware(&firmware_p, rproc->firmware, dev);
> >> - if (ret < 0) {
> >> - dev_err(dev, "request_firmware failed: %d\n", ret);
> >> - return ret;
> >> + if (!rproc_sync_with_mcu(rproc)) {
>
> I guess this is what the original skip_fw_load was doing. And with the
> current series, the userspace loading support usecase I have cannot be
> achieved. If this is added back, I can try if that works for my usecases.
I didn't notice this comment upon first read... Can you give me more details on
what your usecase is order to see how best to deal with it?
Thanks,
Mathieu
>
> >> + ret = request_firmware(&firmware_p, rproc->firmware, dev);
> >> + if (ret < 0) {
> >> + dev_err(dev, "request_firmware failed: %d\n", ret);
> >> + return ret;
> >> + }
> >> }
> >>
> >> ret = rproc_actuate(rproc, firmware_p);
> >>
> >> - release_firmware(firmware_p);
> >> + if (firmware_p)
> >> + release_firmware(firmware_p);
> >>
> >> return ret;
> >> }
> >>
> >> Thanks to these modifications, I'm able to resync after a stop with coprocessor without reloading firmware.
> >>
> >>> ret = rproc_boot(rproc);
> >>> if (ret)
> >>> dev_err(&rproc->dev, "Boot failed: %d\n", ret);
> >>> } else if (sysfs_streq(buf, "stop")) {
> >>> - if (rproc->state != RPROC_RUNNING)
> >>> + if (!rproc_can_shutdown(rproc))
> >>> return -EINVAL;
> >>>
> >>> rproc_shutdown(rproc);
> >> As rproc shutdown is also accessible as kernel API, I propose to move
> >> rproc_can_shutdown() check inside rproc_shutdown() and to test
> >> returned error
> >
> > Ah yes, it is public... As you point out, I think we'll need to move
> > rproc_can_shutdown() in rproc_shutdown().
>
> I am assuming only the new conditions, right?
>
> regards
> Suman
>
> >
> > Thank you for taking the time to review this set,
> > Mathieu
> >
next prev parent reply other threads:[~2020-04-02 20:42 UTC|newest]
Thread overview: 79+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-24 21:45 [PATCH v2 00/17] remoteproc: Add support for synchronisation with MCU Mathieu Poirier
2020-03-24 21:45 ` [PATCH v2 01/17] remoteproc: Add new operation and state machine for MCU synchronisation Mathieu Poirier
2020-03-30 22:46 ` Suman Anna
2020-03-30 22:49 ` Suman Anna
2020-04-01 21:53 ` Mathieu Poirier
2020-04-09 21:38 ` Suman Anna
2020-04-09 21:38 ` Suman Anna
2020-03-24 21:45 ` [PATCH v2 02/17] remoteproc: Introduce function rproc_set_mcu_sync_state() Mathieu Poirier
2020-03-30 22:55 ` Suman Anna
2020-03-24 21:45 ` [PATCH v2 03/17] remoteproc: Split firmware name allocation from rproc_alloc() Mathieu Poirier
2020-03-27 11:05 ` Loic PALLARDY
2020-03-30 19:47 ` Suman Anna
2020-04-01 21:58 ` Mathieu Poirier
2020-03-24 21:45 ` [PATCH v2 04/17] remoteproc: Split rproc_ops " Mathieu Poirier
2020-03-30 19:54 ` Suman Anna
2020-03-24 21:45 ` [PATCH v2 05/17] remoteproc: Get rid of tedious error path Mathieu Poirier
2020-03-30 20:31 ` Suman Anna
2020-03-24 21:45 ` [PATCH v2 06/17] remoteproc: Introduce function rproc_alloc_internals() Mathieu Poirier
2020-03-27 11:10 ` Loic PALLARDY
2020-03-30 20:38 ` Suman Anna
2020-04-01 20:29 ` Mathieu Poirier
2020-04-09 21:53 ` Suman Anna
2020-04-09 21:53 ` Suman Anna
2020-03-30 23:07 ` Mathieu Poirier
2020-03-24 21:45 ` [PATCH v2 07/17] remoteproc: Introduce function rproc_alloc_state_machine() Mathieu Poirier
2020-03-27 13:12 ` Loic PALLARDY
2020-03-30 23:10 ` Suman Anna
2020-04-01 20:41 ` Mathieu Poirier
2020-04-09 18:35 ` Suman Anna
2020-04-09 18:35 ` Suman Anna
2020-03-30 23:13 ` Mathieu Poirier
2020-03-24 21:45 ` [PATCH v2 08/17] remoteproc: Allocate synchronisation state machine Mathieu Poirier
2020-03-27 13:47 ` Loic PALLARDY
2020-03-30 23:16 ` Mathieu Poirier
2020-03-30 23:20 ` Suman Anna
2020-04-01 20:46 ` Mathieu Poirier
2020-03-24 21:45 ` [PATCH v2 09/17] remoteproc: Call the right core function based on synchronisation state Mathieu Poirier
2020-03-31 15:10 ` Suman Anna
2020-04-02 20:16 ` Mathieu Poirier
2020-04-09 18:48 ` Suman Anna
2020-04-09 18:48 ` Suman Anna
2020-03-24 21:45 ` [PATCH v2 10/17] remoteproc: Decouple firmware load and remoteproc booting Mathieu Poirier
2020-03-31 21:27 ` Suman Anna
2020-03-24 21:45 ` [PATCH v2 11/17] remoteproc: Repurpose function rproc_trigger_auto_boot() Mathieu Poirier
2020-03-31 21:32 ` Suman Anna
2020-03-24 21:45 ` [PATCH v2 12/17] remoteproc: Rename function rproc_fw_boot() Mathieu Poirier
2020-03-31 21:42 ` Suman Anna
2020-03-24 21:45 ` [PATCH v2 13/17] remoteproc: Introducting new functions to start and stop an MCU Mathieu Poirier
2020-03-31 18:08 ` Suman Anna
2020-03-31 21:46 ` Suman Anna
2020-04-01 21:55 ` Mathieu Poirier
2020-03-24 21:46 ` [PATCH v2 14/17] remoteproc: Refactor function rproc_trigger_recovery() Mathieu Poirier
2020-03-31 21:52 ` Suman Anna
2020-04-02 20:35 ` Mathieu Poirier
2020-04-09 19:02 ` Suman Anna
2020-04-09 19:02 ` Suman Anna
2020-03-24 21:46 ` [PATCH v2 15/17] remoteproc: Correctly deal with MCU synchronisation when changing FW image Mathieu Poirier
2020-03-27 13:50 ` Loic PALLARDY
2020-03-30 23:21 ` Mathieu Poirier
2020-03-31 22:14 ` Suman Anna
2020-04-01 20:55 ` Mathieu Poirier
2020-04-22 21:29 ` Mathieu Poirier
2020-04-22 21:29 ` Mathieu Poirier
2020-04-22 22:56 ` Suman Anna
2020-04-22 22:56 ` Suman Anna
2020-03-24 21:46 ` [PATCH v2 16/17] remoteproc: Correctly deal with MCU synchronisation when changing state Mathieu Poirier
2020-03-27 14:04 ` Loic PALLARDY
2020-03-30 23:49 ` Mathieu Poirier
2020-03-31 22:35 ` Suman Anna
2020-04-01 21:29 ` Mathieu Poirier
2020-04-09 20:55 ` Suman Anna
2020-04-09 20:55 ` Suman Anna
2020-04-02 20:42 ` Mathieu Poirier [this message]
2020-04-09 20:40 ` Suman Anna
2020-04-09 20:40 ` Suman Anna
2020-03-24 21:46 ` [PATCH v2 17/17] remoteproc: Make MCU synchronisation state changes on stop and crashed Mathieu Poirier
2020-03-27 17:20 ` [PATCH v2 00/17] remoteproc: Add support for synchronisation with MCU Loic PALLARDY
2020-03-31 22:51 ` Suman Anna
2020-04-01 21:39 ` Mathieu Poirier
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200402204231.GC9160@xps15 \
--to=mathieu.poirier@linaro.org \
--cc=arnaud.pouliquen@st.com \
--cc=bjorn.andersson@linaro.org \
--cc=fabien.dessenne@st.com \
--cc=linux-remoteproc@vger.kernel.org \
--cc=loic.pallardy@st.com \
--cc=ohad@wizery.com \
--cc=peng.fan@nxp.com \
--cc=s-anna@ti.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).