From: Greg KH <gregkh@linuxfoundation.org>
To: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: hemantk@codeaurora.org, bbhatt@codeaurora.org,
linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
loic.poulain@linaro.org
Subject: Re: [PATCH 6/8] bus: mhi: core: Add support for processing priority of event ring
Date: Thu, 24 Jun 2021 16:40:38 +0200 [thread overview]
Message-ID: <YNSZZhGSZ0lFgS+U@kroah.com> (raw)
In-Reply-To: <20210624142453.GB6108@workstation>
On Thu, Jun 24, 2021 at 07:54:53PM +0530, Manivannan Sadhasivam wrote:
> 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@codeaurora.org>
> > >
> > > 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@codeaurora.org>
> > > Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org>
> > > Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> > > Link: https://lore.kernel.org/r/1624053903-24653-2-git-send-email-bbhatt@codeaurora.org
> > > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> > > ---
> > > 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.
There's no problem modifying everyone, how much work is that?
> > 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.
Rename it when you change it so that you know you catch all existing
users.
thanks,
greg k-h
next prev parent reply other threads:[~2021-06-24 14:40 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-21 16:16 [PATCH 0/8] MHI patches for v5.14 Manivannan Sadhasivam
2021-06-21 16:16 ` [PATCH 1/8] bus: mhi: core: Validate channel ID when processing command completions Manivannan Sadhasivam
2021-06-24 13:50 ` Greg KH
2021-06-24 14:32 ` Manivannan Sadhasivam
2021-06-24 14:39 ` Greg KH
2021-06-24 14:47 ` Manivannan Sadhasivam
2021-06-24 15:27 ` Greg KH
2021-06-24 15:56 ` Manivannan Sadhasivam
2021-06-21 16:16 ` [PATCH 2/8] bus: mhi: core: Fix power down latency Manivannan Sadhasivam
2021-06-21 16:16 ` [PATCH 3/8] bus: mhi: Wait for M2 state during system resume Manivannan Sadhasivam
2021-06-21 16:16 ` [PATCH 4/8] bus: mhi: Add inbound buffers allocation flag Manivannan Sadhasivam
2021-06-24 13:51 ` Greg KH
2021-06-24 15:39 ` Loic Poulain
2021-06-24 16:48 ` Greg KH
2021-06-24 19:01 ` Loic Poulain
2021-06-21 16:16 ` [PATCH 5/8] bus: mhi: pci-generic: Add missing 'pci_disable_pcie_error_reporting()' calls Manivannan Sadhasivam
2021-06-21 16:16 ` [PATCH 6/8] bus: mhi: core: Add support for processing priority of event ring Manivannan Sadhasivam
2021-06-24 13:53 ` Greg KH
2021-06-24 14:24 ` Manivannan Sadhasivam
2021-06-24 14:40 ` Greg KH [this message]
2021-06-24 14:50 ` Manivannan Sadhasivam
2021-06-21 16:16 ` [PATCH 7/8] bus: mhi: pci_generic: Apply no-op for wake using sideband wake boolean Manivannan Sadhasivam
2021-06-24 13:54 ` Greg KH
2021-06-21 16:16 ` [PATCH 8/8] bus: mhi: pci_generic: Add Cinterion MV31-W PCIe to MHI Manivannan Sadhasivam
2021-06-24 13:54 ` Greg KH
2021-06-24 13:54 ` [PATCH 0/8] MHI patches for v5.14 Greg KH
2021-06-24 14:20 ` Manivannan Sadhasivam
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=YNSZZhGSZ0lFgS+U@kroah.com \
--to=gregkh@linuxfoundation.org \
--cc=bbhatt@codeaurora.org \
--cc=hemantk@codeaurora.org \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=loic.poulain@linaro.org \
--cc=manivannan.sadhasivam@linaro.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).