On Wed, 25 Nov 2020 at 12:58, Manivannan Sadhasivam
<manivannan.sadhasivam@xxxxxxxxxx> wrote:
>
> On Wed, Nov 25, 2020 at 12:23:16PM +0100, Loic Poulain wrote:
> > This patch fixes the hierarchical structure of MHI devices. Indeed,
> > MHI client devices are directly 'enumerated' from the mhi controller
> > and therefore must be direct descendants/children of their mhi
> > controller device, in accordance with the Linux Device Model.
> >
> > Today both MHI clients and controller devices are at the same level,
> > this patch ensures that MHI controller is parent of its client devices.
> >
> > The hierarc /* Only destroy virtual devices thats attached to bus */
> if (mhi_dev->dev_type == MHI_DEVICE_CONTROLLER)
> return 0;hy is especially important for power management (safe
> > suspend/resume order). It is also useful for userspace to determine
> > relationship between MHI client devices and controllers.
> >
> > Signed-off-by: Loic Poulain <loic.poulain@xxxxxxxxxx>
> > Reviewed-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
> > ---
> > v2: fix commit message
> > v3: reword commit message
> > v4: fix device destroy
> >
> > drivers/bus/mhi/core/init.c | 10 +++++++++-
> > drivers/bus/mhi/core/pm.c | 4 ++--
> > 2 files changed, 11 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
> > index 436221c..c7a7354 100644
> > --- a/drivers/bus/mhi/core/init.c
> > +++ b/drivers/bus/mhi/core/init.c
> > @@ -1137,7 +1137,15 @@ struct mhi_device *mhi_alloc_device(struct mhi_controller *mhi_cntrl)
> > device_initialize(dev);
> > dev->bus = &mhi_bus_type;
> > dev->release = mhi_release_device;
> > - dev->parent = mhi_cntrl->cntrl_dev;
> > +
> > + if (mhi_cntrl->mhi_dev) {
> > + /* for MHI client devices, parent is the MHI controller device */
> > + dev->parent = &mhi_cntrl->mhi_dev->dev;
> > + } else {
> > + /* for MHI controller device, parent is the bus device (e.g. pci device) */
> > + dev->parent = mhi_cntrl->cntrl_dev;
> > + }
> > +
> > mhi_dev->mhi_cntrl = mhi_cntrl;
> > mhi_dev->dev_wake = 0;
> >
> > diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
> > index a671f58..681960c 100644
> > --- a/drivers/bus/mhi/core/pm.c
> > +++ b/drivers/bus/mhi/core/pm.c
> > @@ -504,7 +504,7 @@ static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl)
> > wake_up_all(&mhi_cntrl->state_event);
> >
> > dev_dbg(dev, "Reset all active channels and remove MHI devices\n");
> > - device_for_each_child(mhi_cntrl->cntrl_dev, NULL, mhi_destroy_device);
> > + device_for_each_child(&mhi_cntrl->mhi_dev->dev, NULL, mhi_destroy_device);
> >
> > mutex_lock(&mhi_cntrl->pm_mutex);
> >
> > @@ -637,7 +637,7 @@ static void mhi_pm_sys_error_transition(struct mhi_controller *mhi_cntrl)
> > wake_up_all(&mhi_cntrl->state_event);
> >
> > dev_dbg(dev, "Reset all active channels and remove MHI devices\n");
> > - device_for_each_child(mhi_cntrl->cntrl_dev, NULL, mhi_destroy_device);
> > + device_for_each_child(&mhi_cntrl->mhi_dev->dev, NULL, mhi_destroy_device);
>
> Hmm. Now I don't think we need below check in mhi_destroy_device():
>
> /* Only destroy virtual devices thats attached to bus */
> if (mhi_dev->dev_type == MHI_DEVICE_CONTROLLER)
> return 0;
>
> But let's keep it there for sanity.
right.
>
> Have you looked into mhi_debugfs_devices_show()? I guess you need to call
> device_for_each_child() for both "mhi_cntrl->cntrl_dev" and
> "mhi_cntrl->mhi_dev->dev".
Yes, good point, going to address that.
Loic
