Hi Mani,
On 2021-06-18 10:31 AM, Manivannan Sadhasivam wrote:
On Fri, Jun 18, 2021 at 10:17:59AM -0700, Bhaumik Bhatt wrote:
Hi Mani,
On 2021-06-18 12:03 AM, Manivannan Sadhasivam wrote:
> On Thu, Jun 17, 2021 at 02:30:32PM -0700, Bhaumik Bhatt wrote:
> > From: Hemant Kumar <hemantk@xxxxxxxxxxxxxx>
> >
> > Event ring priorities are currently set to 1 and are unused.
> > Default processing priority for event rings is set to regular
> > tasklet. Controllers can choose to use high priority tasklet
> > scheduling for certain event rings critical for processing such
> > as ones transporting control information if they wish to avoid
> > with system scheduling delays for those packets. In order to
> > support these use cases, allow controllers to set event ring
> > priority to high. This patch only adds support and does not
> > enable usage of these priorities.
> >
> > Signed-off-by: Hemant Kumar <hemantk@xxxxxxxxxxxxxx>
> > Signed-off-by: Bhaumik Bhatt <bbhatt@xxxxxxxxxxxxxx>
> > ---
> > drivers/bus/mhi/core/internal.h | 2 +-
> > drivers/bus/mhi/core/main.c | 19 ++++++++++++++++---
> > include/linux/mhi.h | 14 ++++++++++++--
> > 3 files changed, 29 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/bus/mhi/core/internal.h
> > b/drivers/bus/mhi/core/internal.h
> > index 672052f..666e102 100644
> > --- a/drivers/bus/mhi/core/internal.h
> > +++ b/drivers/bus/mhi/core/internal.h
> > @@ -535,7 +535,7 @@ struct mhi_event {
> > u32 intmod;
> > u32 irq;
> > int chan; /* this event ring is dedicated to a channel (optional) */
> > - u32 priority;
> > + enum mhi_er_priority priority;
>
> Instead of using enum for priorities, can we just make use of the
> existing "priority" field? Since the existing controllers set it to "1",
> can we use "0" as the high priority?
>
> This way we don't need to change the controller drivers.
>
I agree but the reasons to do the enum approach was to allow for
future
expansion of the handling if it becomes necessary and provide clarity
for
the field.
I can always do it this way for now and we can have the enum for
another
time but would prefer updating what we have now.
Yeah, let's deal with it later once the necessity arises.
Sure. I will make the v2.
> > enum mhi_er_data_type data_type;
> > struct mhi_ring ring;
> > struct db_cfg db_cfg;
> > diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
> > index 8ac73f9..bfc9776 100644
> > --- a/drivers/bus/mhi/core/main.c
> > +++ b/drivers/bus/mhi/core/main.c
> > @@ -425,10 +425,11 @@ void mhi_create_devices(struct mhi_controller
> > *mhi_cntrl)
> > }
> > }
> >
[...]
Existing controllers would be fine.
Do you think we have a problem if a new controller blindly inputs a
"0" in
the priority not knowing the impact of it?
We should document it in the kernel doc for the struct field and that
should be enough. We can't do much if people doesn't read the doc ;)
Thanks,
Mani
Totally agree :)
If you give me a go ahead, I can make these changes in v2 and leave
the enum
stuff out.
Thanks,
Bhaumik
---
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Forum,
a Linux Foundation Collaborative Project
Thanks,
Bhaumik
---
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora
Forum,
a Linux Foundation Collaborative Project
