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Message-ID: <20210217212251.GA2800385@xps15>
Date: Wed, 17 Feb 2021 14:22:51 -0700
From: Mathieu Poirier <mathieu.poirier@...aro.org>
To: Arnaud POULIQUEN <arnaud.pouliquen@...s.st.com>
Cc: ohad@...ery.com, bjorn.andersson@...aro.org,
arnaud.pouliquen@...com, robh+dt@...nel.org,
mcoquelin.stm32@...il.com, alexandre.torgue@...com,
linux-remoteproc@...r.kernel.org, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v5 07/19] remoteproc: Add new get_loaded_rsc_table() to
rproc_ops
On Mon, Feb 15, 2021 at 02:10:10PM +0100, Arnaud POULIQUEN wrote:
> Hi Mathieu,
>
> On 2/12/21 12:46 AM, Mathieu Poirier wrote:
> > Add a new get_loaded_rsc_table() operation in order to support
> > scenarios where the remoteproc core has booted a remote processor
> > and detaches from it. When re-attaching to the remote processor,
> > the core needs to know where the resource table has been placed
> > in memory.
> >
> > Signed-off-by: Mathieu Poirier <mathieu.poirier@...aro.org>
> > ---
> > New for V5:
> > - Added function rproc_set_loaded_rsc_table() to keep rproc_attach() clean.
> > - Setting ->cached_table, ->table_ptr and ->table_sz in the remoteproc core
> > rather than the platform drivers.
> > ---
> > drivers/remoteproc/remoteproc_core.c | 35 ++++++++++++++++++++++++
> > drivers/remoteproc/remoteproc_internal.h | 10 +++++++
> > include/linux/remoteproc.h | 6 +++-
> > 3 files changed, 50 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> > index e6606d10a4c8..741bc20de437 100644
> > --- a/drivers/remoteproc/remoteproc_core.c
> > +++ b/drivers/remoteproc/remoteproc_core.c
> > @@ -1537,6 +1537,35 @@ static int rproc_fw_boot(struct rproc *rproc, const struct firmware *fw)
> > return ret;
> > }
> >
> > +static int rproc_set_loaded_rsc_table(struct rproc *rproc)
> > +{
> > + struct resource_table *table_ptr;
> > + struct device *dev = &rproc->dev;
> > + size_t table_sz;
> > + int ret;
> > +
> > + table_ptr = rproc_get_loaded_rsc_table(rproc, &table_sz);
> > + if (IS_ERR_OR_NULL(table_ptr)) {
> > + if (!table_ptr)
> > + ret = -EINVAL;
>
> I did few tests on this showing that this approach does not cover all use cases.
>
> The first one is a firmware without resource table. In this case table_ptr
> should be null, or we have to consider the -ENOENT error as a non error usecase.
>
Right, I'll provision for those cases.
> The second one, more tricky, is a firmware started by the remoteproc framework.
> In this case the resource table address is retrieved from the ELF file by the
> core part.
Correct.
> So if we detach and reattach rproc_get_loaded_rsc_table cannot return the
> address. Look to me that we should have also an alocation of the clean_table in
> rproc_start and then to keep the memory allocated until a shutdown.
I assumed the address of the resource table found in the ELF image was the same
as the one known by the platform driver. In hindsight I realise the platform
driver may not know that address.
>
> That said regarding the complexity to re-attach, I wonder if it would not be
> better to focus first on a simple detach, and address the reattachment in a
> separate series, to move forward in stages.
I agree that OFFLINE -> RUNNING -> DETACHED -> ATTACHED is introducing some
complexity related to the management of the resource table that where not
expected. We could concentrate on a simple detach and see where that takes us.
It would also mean to get rid of the "autonomous-on-core-shutdown" DT binding.
Thanks,
Mathieu
>
> Regards,
> Arnaud
>
> > + else
> > + ret = PTR_ERR(table_ptr);
> > +
> > + dev_err(dev, "can't load resource table: %d\n", ret);
> > + return ret;
> > + }
> > +
> > + /*
> > + * The resource table is already loaded in device memory, no need
> > + * to work with a cached table.
> > + */
> > + rproc->cached_table = NULL;
> > + rproc->table_ptr = table_ptr;
> > + rproc->table_sz = table_sz;
> > +
> > + return 0;
> > +}
> > +
> > /*
> > * Attach to remote processor - similar to rproc_fw_boot() but without
> > * the steps that deal with the firmware image.
> > @@ -1556,6 +1585,12 @@ static int rproc_attach(struct rproc *rproc)
> > return ret;
> > }
> >
> > + ret = rproc_set_loaded_rsc_table(rproc);
> > + if (ret) {
> > + dev_err(dev, "can't load resource table: %d\n", ret);
> > + goto disable_iommu;
> > + }
> > +
> > /* reset max_notifyid */
> > rproc->max_notifyid = -1;
> >
> > diff --git a/drivers/remoteproc/remoteproc_internal.h b/drivers/remoteproc/remoteproc_internal.h
> > index c34002888d2c..4f73aac7e60d 100644
> > --- a/drivers/remoteproc/remoteproc_internal.h
> > +++ b/drivers/remoteproc/remoteproc_internal.h
> > @@ -177,6 +177,16 @@ struct resource_table *rproc_find_loaded_rsc_table(struct rproc *rproc,
> > return NULL;
> > }
> >
> > +static inline
> > +struct resource_table *rproc_get_loaded_rsc_table(struct rproc *rproc,
> > + size_t *size)
> > +{
> > + if (rproc->ops->get_loaded_rsc_table)
> > + return rproc->ops->get_loaded_rsc_table(rproc, size);
> > +
> > + return NULL;
> > +}
> > +
> > static inline
> > bool rproc_u64_fit_in_size_t(u64 val)
> > {
> > diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
> > index 6b0a0ed30a03..51538a7d120d 100644
> > --- a/include/linux/remoteproc.h
> > +++ b/include/linux/remoteproc.h
> > @@ -368,7 +368,9 @@ enum rsc_handling_status {
> > * RSC_HANDLED if resource was handled, RSC_IGNORED if not handled and a
> > * negative value on error
> > * @load_rsc_table: load resource table from firmware image
> > - * @find_loaded_rsc_table: find the loaded resouce table
> > + * @find_loaded_rsc_table: find the loaded resource table from firmware image
> > + * @get_loaded_rsc_table: get resource table installed in memory
> > + * by external entity
> > * @load: load firmware to memory, where the remote processor
> > * expects to find it
> > * @sanity_check: sanity check the fw image
> > @@ -390,6 +392,8 @@ struct rproc_ops {
> > int offset, int avail);
> > struct resource_table *(*find_loaded_rsc_table)(
> > struct rproc *rproc, const struct firmware *fw);
> > + struct resource_table *(*get_loaded_rsc_table)(
> > + struct rproc *rproc, size_t *size);
> > int (*load)(struct rproc *rproc, const struct firmware *fw);
> > int (*sanity_check)(struct rproc *rproc, const struct firmware *fw);
> > u64 (*get_boot_addr)(struct rproc *rproc, const struct firmware *fw);
> >
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