From: Mathieu Poirier <mathieu.poirier@linaro.org>
To: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: ohad@wizery.com, loic.pallardy@st.com, arnaud.pouliquen@st.com,
s-anna@ti.com, linux-remoteproc@vger.kernel.org, corbet@lwn.net,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 05/14] remoteproc: Refactor function rproc_fw_boot()
Date: Fri, 15 May 2020 13:46:51 -0600 [thread overview]
Message-ID: <20200515194651.GB24201@xps15> (raw)
In-Reply-To: <20200514021055.GF16107@builder.lan>
On Wed, May 13, 2020 at 07:10:55PM -0700, Bjorn Andersson wrote:
> On Fri 08 May 14:27 PDT 2020, Mathieu Poirier wrote:
>
> > On Tue, May 05, 2020 at 05:33:41PM -0700, Bjorn Andersson wrote:
> > > On Fri 24 Apr 13:01 PDT 2020, Mathieu Poirier wrote:
> > >
> > > > Refactor function rproc_fw_boot() in order to better reflect the work
> > > > that is done when supporting scenarios where the remoteproc core is
> > > > synchronising with a remote processor.
> > > >
> > > > Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
> > > > ---
> > > > drivers/remoteproc/remoteproc_core.c | 10 ++++++----
> > > > 1 file changed, 6 insertions(+), 4 deletions(-)
> > > >
> > > > diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> > > > index a02593b75bec..e90a21de9de1 100644
> > > > --- a/drivers/remoteproc/remoteproc_core.c
> > > > +++ b/drivers/remoteproc/remoteproc_core.c
> > > > @@ -1370,9 +1370,9 @@ static int rproc_start(struct rproc *rproc, const struct firmware *fw)
> > > > }
> > > >
> > > > /*
> > > > - * take a firmware and boot a remote processor with it.
> > > > + * boot or synchronise with a remote processor.
> > > > */
> > > > -static int rproc_fw_boot(struct rproc *rproc, const struct firmware *fw)
> > > > +static int rproc_actuate_device(struct rproc *rproc, const struct firmware *fw)
> > >
> > > Per patch 4 this function will if rproc_needs_syncing() be called with
> > > fw == NULL, it's not obvious to me that the various operations on "fw"
> > > in this function are valid anymore.
> >
> > That is right, all firmware related operations in this function are found in
> > remoteproc_internal.h where the value of rproc->sync_with_mcu is checked before
> > moving forward. That allows us to avoid introducing a new function similar to
> > rproc_fw_boot() but without firmware operations or peppering the code with if
> > statements.
> >
>
> As I wrote in my other reply, the two mechanisms seems to consist of the
> following steps:
>
> boot the core:
> 1) request firmware
> 2) prepare device
> 3) parse fw
> 4) handle resources
> 5) allocate carveouts
> 6) load segments
> 7) find resource table
> 8) prepare subdevices
> 9) power on
> 10) start subdevices
>
> sync:
> 1) prepare device (?)
> 2) handle resources
> 3) allocate carveouts (?)
> 4) prepare subdevices
> 5) attach
> 6) start subdevices
>
> Rather than relying on the state flag and missing ops will turn the
> first list into the second list I conceptually prefer having two
> separate functions that are easy to reason about.
I reflected long and hard about doing just that...
>
> But I haven't done any refactoring or implemented this, so in practice
> the two might just be a lot of duplication(?)
Exactly - duplication and maintenance are my prime concern. Right now some
functions in the OFFLINE -> RUNNING are clearly not needed when dealing with a
DETACHED -> RUNNING scenarios, but with I am convinced people will find ways to
do something creative with the callbacks. In the end I fear the new functions
we spin off to deal with DETACHED -> RUNNING scenarios will end up looking very
similar to the current implementation.
With that in mind I simply did all the work in remoteproc_internal.h and left
the core functions intact.
We can try spinning off new functions in the next revision, just to test my
theory and see how much gets duplicated.
>
> > >
> > > > {
> > > > struct device *dev = &rproc->dev;
> > > > const char *name = rproc->firmware;
> > > > @@ -1382,7 +1382,9 @@ static int rproc_fw_boot(struct rproc *rproc, const struct firmware *fw)
> > > > if (ret)
> > > > return ret;
> > > >
> > > > - dev_info(dev, "Booting fw image %s, size %zd\n", name, fw->size);
> > > > + if (!rproc_needs_syncing(rproc))
> > >
> > > Can't we make this check on fw, to make the relationship "if we where
> > > passed a firmware object, we're going to load and boot that firmware"?
> >
> > It can but I specifically decided to use rproc_needs_syncing() to be consistent
> > with the rest of the patchset. That way all we need to do is grep for
> > rproc_needs_syncing to get all the places where a decision about synchronising
> > with a remote processor is made.
> >
>
> Conceptually we have a single "to sync or not to sync", but I think
> we're invoking rproc_needs_syncing() 8 times during rproc_fw_boot() and
> each of those operations may or may not do anything.
As I said above, I'll try spinning off new functions in the next revision. From
there we can decide how best to move forward.
>
> There are certain operations where I see it makes sense for a driver to
> either implement or not, but I think that e.g. for a rproc in OFFLINE
> state we should just require ops->start to be specified - because it
> doesn't make sense to enter rproc_start() if ops->start is a nop.
At this time ops->start() doesn't have to be specified... But as you say it
won't do much good and this is something we can easily spot when reviewing
patches.
Thanks for the review,
Mathieu
>
> Regards,
> Bjorn
>
> > >
> > > Regards,
> > > Bjorn
> > >
> > > > + dev_info(dev, "Booting fw image %s, size %zd\n",
> > > > + name, fw->size);
> > > >
> > > > /*
> > > > * if enabling an IOMMU isn't relevant for this rproc, this is
> > > > @@ -1818,7 +1820,7 @@ int rproc_boot(struct rproc *rproc)
> > > > }
> > > > }
> > > >
> > > > - ret = rproc_fw_boot(rproc, firmware_p);
> > > > + ret = rproc_actuate_device(rproc, firmware_p);
> > > >
> > > > release_firmware(firmware_p);
> > > >
> > > > --
> > > > 2.20.1
> > > >
next prev parent reply other threads:[~2020-05-15 19:46 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-24 20:01 [PATCH v3 00/14] remoteproc: Add support for synchronisaton with rproc Mathieu Poirier
2020-04-24 20:01 ` [PATCH v3 01/14] remoteproc: Make core operations optional Mathieu Poirier
2020-04-28 16:18 ` Arnaud POULIQUEN
2020-04-30 19:39 ` Mathieu Poirier
2020-05-05 22:16 ` Bjorn Andersson
2020-05-08 19:09 ` Mathieu Poirier
2020-04-24 20:01 ` [PATCH v3 02/14] remoteproc: Introduce function rproc_alloc_internals() Mathieu Poirier
2020-05-05 22:31 ` Bjorn Andersson
2020-05-08 19:37 ` Mathieu Poirier
2020-04-24 20:01 ` [PATCH v3 03/14] remoteproc: Add new operation and flags for synchronistation Mathieu Poirier
2020-04-28 16:38 ` Arnaud POULIQUEN
2020-04-30 19:49 ` Mathieu Poirier
2020-05-06 0:22 ` Bjorn Andersson
2020-05-08 21:01 ` Mathieu Poirier
2020-05-14 1:32 ` Bjorn Andersson
2020-05-15 19:24 ` Mathieu Poirier
2020-05-19 0:55 ` Bjorn Andersson
2020-05-20 22:06 ` Mathieu Poirier
2020-05-21 5:21 ` Bjorn Andersson
2020-05-21 21:55 ` Mathieu Poirier
2020-04-24 20:01 ` [PATCH v3 04/14] remoteproc: Refactor function rproc_boot() Mathieu Poirier
2020-04-24 20:01 ` [PATCH v3 05/14] remoteproc: Refactor function rproc_fw_boot() Mathieu Poirier
2020-05-06 0:33 ` Bjorn Andersson
2020-05-08 21:27 ` Mathieu Poirier
2020-05-14 2:10 ` Bjorn Andersson
2020-05-15 19:46 ` Mathieu Poirier [this message]
2020-05-19 0:22 ` Bjorn Andersson
2020-04-24 20:01 ` [PATCH v3 06/14] remoteproc: Refactor function rproc_trigger_auto_boot() Mathieu Poirier
2020-04-28 17:00 ` Arnaud POULIQUEN
2020-04-24 20:01 ` [PATCH v3 07/14] remoteproc: Introducting new start and stop functions Mathieu Poirier
2020-05-06 0:42 ` Bjorn Andersson
2020-04-24 20:01 ` [PATCH v3 08/14] remoteproc: Call core functions based on synchronisation flag Mathieu Poirier
2020-04-28 17:27 ` Arnaud POULIQUEN
2020-04-30 19:57 ` Mathieu Poirier
2020-05-04 11:14 ` Arnaud POULIQUEN
2020-05-05 22:10 ` Mathieu Poirier
2020-04-24 20:01 ` [PATCH v3 09/14] remoteproc: Deal with synchronisation when crashing Mathieu Poirier
2020-04-29 7:44 ` Arnaud POULIQUEN
2020-04-30 20:11 ` Mathieu Poirier
2020-05-06 1:01 ` Bjorn Andersson
2020-05-08 21:47 ` Mathieu Poirier
2020-04-24 20:01 ` [PATCH v3 10/14] remoteproc: Deal with synchronisation when shutting down Mathieu Poirier
2020-04-29 8:19 ` Arnaud POULIQUEN
2020-04-30 20:23 ` Mathieu Poirier
2020-05-04 11:34 ` Arnaud POULIQUEN
2020-05-05 22:03 ` Mathieu Poirier
2020-05-06 7:51 ` Arnaud POULIQUEN
2020-05-06 1:10 ` Bjorn Andersson
2020-04-24 20:01 ` [PATCH v3 11/14] remoteproc: Deal with synchronisation when changing FW image Mathieu Poirier
2020-04-29 8:52 ` Arnaud POULIQUEN
2020-04-30 20:32 ` Mathieu Poirier
2020-05-06 1:27 ` Bjorn Andersson
2020-04-24 20:01 ` [PATCH v3 12/14] remoteproc: Introducing function rproc_set_state_machine() Mathieu Poirier
2020-04-29 9:22 ` Arnaud POULIQUEN
2020-04-29 14:38 ` Arnaud POULIQUEN
2020-04-30 20:51 ` Mathieu Poirier
2020-05-04 12:00 ` Arnaud POULIQUEN
2020-04-30 20:42 ` Mathieu Poirier
2020-05-04 11:57 ` Arnaud POULIQUEN
2020-05-05 21:43 ` Mathieu Poirier
2020-04-24 20:01 ` [PATCH v3 13/14] remoteproc: Document " Mathieu Poirier
2020-04-24 20:01 ` [PATCH v3 14/14] remoteproc: Expose synchronisation flags via debugfs Mathieu Poirier
2020-05-18 13:28 ` [PATCH v3 00/14] remoteproc: Add support for synchronisaton with rproc Peng Fan
2020-05-18 16:29 ` Mathieu Poirier
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