On Thu, Jun 24, 2021 at 03:53:33PM +0200, Greg KH wrote: > On Mon, Jun 21, 2021 at 09:46:14PM +0530, Manivannan Sadhasivam 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 > > system scheduling delays for those packets. In order to support > > these use cases, allow controllers to set event ring priority to > > high. > > > > Signed-off-by: Hemant Kumar <hemantk@xxxxxxxxxxxxxx> > > Signed-off-by: Bhaumik Bhatt <bbhatt@xxxxxxxxxxxxxx> > > Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> > > Link: https://lore.kernel.org/r/1624053903-24653-2-git-send-email-bbhatt@xxxxxxxxxxxxxx > > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> > > --- > > drivers/bus/mhi/core/init.c | 3 +-- > > drivers/bus/mhi/core/main.c | 9 +++++++-- > > include/linux/mhi.h | 2 +- > > 3 files changed, 9 insertions(+), 5 deletions(-) > > > > diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c > > index c81b377fca8f..444676034bf0 100644 > > --- a/drivers/bus/mhi/core/init.c > > +++ b/drivers/bus/mhi/core/init.c > > @@ -673,8 +673,7 @@ static int parse_ev_cfg(struct mhi_controller *mhi_cntrl, > > &mhi_cntrl->mhi_chan[mhi_event->chan]; > > } > > > > - /* Priority is fixed to 1 for now */ > > - mhi_event->priority = 1; > > + mhi_event->priority = event_cfg->priority; > > > > mhi_event->db_cfg.brstmode = event_cfg->mode; > > if (MHI_INVALID_BRSTMODE(mhi_event->db_cfg.brstmode)) > > diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c > > index 8ac73f9e92a6..3775c77dec63 100644 > > --- a/drivers/bus/mhi/core/main.c > > +++ b/drivers/bus/mhi/core/main.c > > @@ -454,10 +454,15 @@ irqreturn_t mhi_irq_handler(int irq_number, void *dev) > > > > if (mhi_dev) > > mhi_notify(mhi_dev, MHI_CB_PENDING_DATA); > > - } else { > > - tasklet_schedule(&mhi_event->task); > > + > > + return IRQ_HANDLED; > > } > > > > + if (!mhi_event->priority) > > + tasklet_hi_schedule(&mhi_event->task); > > + else > > + tasklet_schedule(&mhi_event->task); > > + > > return IRQ_HANDLED; > > } > > > > diff --git a/include/linux/mhi.h b/include/linux/mhi.h > > index 86cea5256e3c..bf23c213429c 100644 > > --- a/include/linux/mhi.h > > +++ b/include/linux/mhi.h > > @@ -250,7 +250,7 @@ struct mhi_channel_config { > > * @irq_moderation_ms: Delay irq for additional events to be aggregated > > * @irq: IRQ associated with this ring > > * @channel: Dedicated channel number. U32_MAX indicates a non-dedicated ring > > - * @priority: Priority of this ring. Use 1 for now > > + * @priority: Processing priority of this ring. 0 is high and 1 is regular > > Why is 0 high and 1 low? Does that feel backwards? > That's because, "1" was used from the beginning by the controller drivers as the regular priority. And I thought of using "0" as high priority so that we can leave the controller drivers unmodified. > Shouldn't this be a boolean, or if not, an enumerated type so that > people can read the code over time? > Bhaumik proposed an enum but I wanted 0/1 so that the controller drivers can be untouched. Also, I don't see any immediate requirement for other priorities. Will make it a bool then. Thanks, Mani > thanks, > > greg k-h
