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SubjectRE: [PATCH 2/2] firmware: imx: MU IRQ group number should be 7
Date
> From: Anson Huang <anson.huang@nxp.com>
> Sent: Friday, April 24, 2020 10:36 AM
>
> > -----Original Message-----
> > From: Aisheng Dong <aisheng.dong@nxp.com>
> > Sent: 2020年4月24日 10:33
> > To: Anson Huang <anson.huang@nxp.com>; shawnguo@kernel.org;
> > s.hauer@pengutronix.de; kernel@pengutronix.de; festevam@gmail.com;
> > ben.dooks@codethink.co.uk; linux-arm-kernel@lists.infradead.org;
> > linux-kernel@vger.kernel.org
> > Cc: dl-linux-imx <linux-imx@nxp.com>
> > Subject: RE: [PATCH 2/2] firmware: imx: MU IRQ group number should be
> > 7
> >
> > > From: Anson Huang <Anson.Huang@nxp.com>
> > > Sent: Friday, April 24, 2020 7:07 AM
> > >
> > > The MU IRQ group number should be 7 instead of 4.
> > >
> > > Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
> >
> > Are we using others IRQ group?
> > If not, this change may slow down the irq handling speed.
>
> The irq handling is using work queue, NOT in ISR, so the speed is NOT that
> sensitive.

SCU IPC is shared by the whole system, each SCU transfer takes about 10~20 us.
Here you may waste 30~60us if not really used.

> The scu group irq driver should provide full functions, as other drivers using it
> may enable the group they want.

Below are extra GROUPs you're going to add:
#define SC_IRQ_GROUP_SYSCTR 4U /*!< System counter interrupts */
#define SC_IRQ_GROUP_REBOOTED 5U /*!< Partition reboot complete */
#define SC_IRQ_GROUP_REBOOT 6U /*!< Partition reboot starting */
Are we really going to use it? It seems I also didn't see any users in downstream tree.

Some functions provided by SCFW may not really used by Linux.
I think I's better to add them when we really need them, otherwise we benefit nothing
But wasting CPU mips.

Regards
Aisheng

>
> Anson
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