On Fri 14 Feb 12:46 PST 2020, Mathieu Poirier wrote:
> On Wed, Feb 12, 2020 at 06:54:03PM +0100, Loic Poulain wrote:
> > There is no guarantee that the iris pointer will be assigned before
> > remoteproc subsystem starts the wcnss rproc, actually it depends how
> > fast rproc subsystem is able to get the firmware to trigger the start.
> >
> > This leads to sporadic wifi/bluetooth initialization issue on db410c
> > with the following output:
> > remoteproc remoteproc1: powering up a204000.wcnss
> > remoteproc remoteproc1: Booting fw image qcom/msm8916/wcnss.mdt...
> > qcom-wcnss-pil a204000.wcnss: no iris registered
> > remoteproc remoteproc1: can't start rproc a204000.wcnss: -22
> >
> > This patch introduces a 'iris_assigned' completion barrier to fix
> > this issue. Maybe not the most elegant way, but it does the trick.
> >
> > Signed-off-by: Loic Poulain <loic.poulain@xxxxxxxxxx>
> > ---
> > drivers/remoteproc/qcom_wcnss.c | 7 +++++++
> > 1 file changed, 7 insertions(+)
> >
> > diff --git a/drivers/remoteproc/qcom_wcnss.c b/drivers/remoteproc/qcom_wcnss.c
> > index a0468b3..c888282 100644
> > --- a/drivers/remoteproc/qcom_wcnss.c
> > +++ b/drivers/remoteproc/qcom_wcnss.c
> > @@ -84,6 +84,7 @@ struct qcom_wcnss {
> >
> > struct completion start_done;
> > struct completion stop_done;
> > + struct completion iris_assigned;
> >
> > phys_addr_t mem_phys;
> > phys_addr_t mem_reloc;
> > @@ -138,6 +139,7 @@ void qcom_wcnss_assign_iris(struct qcom_wcnss *wcnss,
> >
> > wcnss->iris = iris;
> > wcnss->use_48mhz_xo = use_48mhz_xo;
> > + complete(&wcnss->iris_assigned);
> >
> > mutex_unlock(&wcnss->iris_lock);
> > }
> > @@ -213,6 +215,10 @@ static int wcnss_start(struct rproc *rproc)
> > struct qcom_wcnss *wcnss = (struct qcom_wcnss *)rproc->priv;
> > int ret;
> >
> > + /* Grant some time for iris registration */
> > + wait_for_completion_timeout(&wcnss->iris_assigned,
> > + msecs_to_jiffies(5000));
> > +
> > mutex_lock(&wcnss->iris_lock);
> > if (!wcnss->iris) {
> > dev_err(wcnss->dev, "no iris registered\n");
> > @@ -494,6 +500,7 @@ static int wcnss_probe(struct platform_device *pdev)
> >
> > init_completion(&wcnss->start_done);
> > init_completion(&wcnss->stop_done);
> > + init_completion(&wcnss->iris_assigned);
> >
> > mutex_init(&wcnss->iris_lock);
>
> If I understand the problem correctly, if loading the fw image takes long enough,
> qcom_iris_probe() that is triggered by of_platform_populate() has time to
> complete and call qcom_wcnss_assign_iris(). Otherwise the remoteproc core calls
> wcnss_start() before qcom_wcnss_assign_iris() had the opportunity to run.
>
> If I am correct, would it be possible to call of_platform_populate() before
> calling rproc_add()? There might be some refactoring to do but that's probably
> better than introducing a delay...
>
We'll still have the problem that if the iris device probe defer on the
regulators it still might not be in place when we're hitting
wcnss_start().
Unfortunately we need a struct device with the iris of_node associated,
in order get hold of the regulators, but we should be able to drop the
platform_driver and the probing in favor of just making up a struct
device, associating it with the of_node and requesting the iris
regulators using this.
That would remove the whole timing aspect and we can properly probe
defer the qcom_wcnss when the iris regulators are not yet in place.
Regards,
Bjorn
