Re: [[PATCH] 8/9] DMA-UART-Driver-for-AST2500

Benjamin Herrenschmidt
2018-10-18T23:32:24Z

On Thu, 2018-10-18 at 15:25 +0530, Vinod wrote:
>
> > It's not a dmaengine driver. It's a serial UART driver that happens to
> > use a dedicated DMA engine.
>
> Then I see no reason for it to use dmaengine APIs. The framework allows
> people to share a controller for many clients, but if you have dedicated
> one then you may use it directly

Well... the engine is shared by a few UARTs, they have dedicated rings
but there's a common set of regs for interrupt handling etc.

That said, I still think it could be contained within a UART driver,
there's little benefit in adding the framework overhead, esp since
these are really weak cores, any overhead will be felt.

Ben.

> > It's unclear whether it should be split into two drivers, or just have
> > the serial driver directly use the dma engine since that engine is
> > dedicated in HW to only work on those UARTs and nothing else...
> >
> > Cheers,
> > Ben.
> >
> >
> > > While doing resubmission please take some time to understand subsystem
> > > tags to use. (hint git log <subsystem> will tell you)
> > >
> > > Also series has [[PATCH] 8/9] whereas it should be [PATCH 8/9] please
> > > let git generate that for you (hint git format-patch start..end does a
> > > good job)
> > >
> > > > @@ -0,0 +1,1594 @@
> > > > +// SPDX-License-Identifier: GPL-2.0
> > > > +/*
> > > > + * drivers/tty/serial/8250/8250_aspeed_uart_dma.c
> > > > + * 1. 2018/07/01 Shivah Shankar created
> > > > + * 2. 2018/08/25 sudheer.veliseti<open.sudheer@gmail.com> modified
> > >
> > > we dont use this log in kernel. I do not see s-o-b by Shivah, that
> > > should be added. I think he should be author and you need to list
> > > changes you did..
> > >
>
>