Re: [PATCH v7 3/5] remoteproc: Add support for runtime PM

[Paul Cercueil]

Hi Suman,

Le ven. 22 mai 2020 à 11:47, Suman Anna <s-anna@xxxxxx> a écrit :
> Hi Paul,
>
> On 5/15/20 5:43 AM, Paul Cercueil wrote:
> > Call pm_runtime_get_sync() before the firmware is loaded, and
> > pm_runtime_put() after the remote processor has been stopped.
> >
> > Even though the remoteproc device has no PM callbacks, this allows 
> > the
> > parent device's PM callbacks to be properly called.
>
> I see this patch staged now for 5.8, and the latest -next branch has 
> broken the pm-runtime autosuspend feature we have in the OMAP 
> remoteproc driver. See commit 5f31b232c674 ("remoteproc/omap: Add 
> support for runtime auto-suspend/resume").
>
> What was the original purpose of this patch, because there can be 
> differing backends across different SoCs.

Did you try pm_suspend_ignore_children()? It looks like it was made for 
your use-case.

Cheers,
-Paul

> regards
> Suman
>
> > Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
> > ---
> >
> > Notes:
> >      v2-v4: No change
> >      v5: Move calls to prepare/unprepare to 
> > rproc_fw_boot/rproc_shutdown
> >      v6: Instead of prepare/unprepare callbacks, use PM runtime 
> > callbacks
> >      v7: Check return value of pm_runtime_get_sync()
> >
> >   drivers/remoteproc/remoteproc_core.c | 17 ++++++++++++++++-
> >   1 file changed, 16 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/remoteproc/remoteproc_core.c 
> > b/drivers/remoteproc/remoteproc_core.c
> > index a7f96bc98406..e33d1ef27981 100644
> > --- a/drivers/remoteproc/remoteproc_core.c
> > +++ b/drivers/remoteproc/remoteproc_core.c
> > @@ -29,6 +29,7 @@
> >   #include <linux/devcoredump.h>
> >   #include <linux/rculist.h>
> >   #include <linux/remoteproc.h>
> > +#include <linux/pm_runtime.h>
> >   #include <linux/iommu.h>
> >   #include <linux/idr.h>
> >   #include <linux/elf.h>
> > @@ -1382,6 +1383,12 @@ static int rproc_fw_boot(struct rproc *rproc, 
> > const struct firmware *fw)
> >   	if (ret)
> >   		return ret;
> >   +	ret = pm_runtime_get_sync(dev);
> > +	if (ret < 0) {
> > +		dev_err(dev, "pm_runtime_get_sync failed: %d\n", ret);
> > +		return ret;
> > +	}
> > +
> >   	dev_info(dev, "Booting fw image %s, size %zd\n", name, fw->size);
> >     	/*
> > @@ -1391,7 +1398,7 @@ static int rproc_fw_boot(struct rproc *rproc, 
> > const struct firmware *fw)
> >   	ret = rproc_enable_iommu(rproc);
> >   	if (ret) {
> >   		dev_err(dev, "can't enable iommu: %d\n", ret);
> > -		return ret;
> > +		goto put_pm_runtime;
> >   	}
> >     	rproc->bootaddr = rproc_get_boot_addr(rproc, fw);
> > @@ -1435,6 +1442,8 @@ static int rproc_fw_boot(struct rproc *rproc, 
> > const struct firmware *fw)
> >   	rproc->table_ptr = NULL;
> >   disable_iommu:
> >   	rproc_disable_iommu(rproc);
> > +put_pm_runtime:
> > +	pm_runtime_put(dev);
> >   	return ret;
> >   }
> >   @@ -1840,6 +1849,8 @@ void rproc_shutdown(struct rproc *rproc)
> >     	rproc_disable_iommu(rproc);
> >   +	pm_runtime_put(dev);
> > +
> >   	/* Free the copy of the resource table */
> >   	kfree(rproc->cached_table);
> >   	rproc->cached_table = NULL;
> > @@ -2118,6 +2129,9 @@ struct rproc *rproc_alloc(struct device *dev, 
> > const char *name,
> >     	rproc->state = RPROC_OFFLINE;
> >   +	pm_runtime_no_callbacks(&rproc->dev);
> > +	pm_runtime_enable(&rproc->dev);
> > +
> >   	return rproc;
> >   }
> >   EXPORT_SYMBOL(rproc_alloc);
> > @@ -2133,6 +2147,7 @@ EXPORT_SYMBOL(rproc_alloc);
> >    */
> >   void rproc_free(struct rproc *rproc)
> >   {
> > +	pm_runtime_disable(&rproc->dev);
> >   	put_device(&rproc->dev);
> >   }
> >   EXPORT_SYMBOL(rproc_free);