Re: [RFC PATCH v2 11/11] riscv: soc: Allwinner D1 GMAC driver only for temp use

From: "Jernej Škrabec" <jernej.skrabec@gmail.com>
To: Andre Przywara <andre.przywara@arm.com>, Guo Ren <guoren@kernel.org>
Cc: "Anup Patel" <anup.patel@wdc.com>,
	"Palmer Dabbelt" <palmerdabbelt@google.com>,
	"Arnd Bergmann" <arnd@arndb.de>,
	wens@csie.org, maxime@cerno.tech,
	"Drew Fustini" <drew@beagleboard.org>,
	liush@allwinnertech.com, "Wei Wu (吴伟)" <lazyparser@gmail.com>,
	wefu@redhat.com, linux-riscv <linux-riscv@lists.infradead.org>,
	"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
	linux-arch <linux-arch@vger.kernel.org>,
	linux-sunxi@lists.linux.dev, "Maxime Ripard" <mripard@kernel.org>,
	"Corentin Labbe" <clabbe@baylibre.com>,
	"Samuel Holland" <samuel@sholland.org>,
	"Icenowy Zheng" <icenowy@aosc.io>,
	"LABBE Corentin" <clabbe.montjoie@gmail.com>,
	"Michael Walle" <michael@walle.cc>,
	"Guo Ren" <guoren@linux.alibaba.com>
Subject: Re: [RFC PATCH v2 11/11] riscv: soc: Allwinner D1 GMAC driver only for temp use
Date: Sun, 06 Jun 2021 17:39:09 +0200	[thread overview]
Message-ID: <49182865.cm8dGOVcTj@jernej-laptop> (raw)
In-Reply-To: <CAJF2gTQgaJFW9knuVmW8J8zMAt_Gtq3KJ9gsGKg6=xLBuq0=uA@mail.gmail.com>

Hi!

Dne nedelja, 06. junij 2021 ob 17:32:22 CEST je Guo Ren napisal(a):
>  ,
> 
> On Sun, Jun 6, 2021 at 6:50 PM Andre Przywara <andre.przywara@arm.com> 
wrote:
> > On Sun,  6 Jun 2021 09:04:09 +0000
> > guoren@kernel.org wrote:
> > 
> > Hi,
> > 
> > > From: liush <liush@allwinnertech.com>
> > > 
> > > This is a temporary driver, only guaranteed to work on allwinner
> > > D1. In order to ensure the developer's demand for network usage.
> > 
> > That looks like some Allwinner BSP driver, please don't endorse code
> > of this quality (just look at all that commented code and the attempt
> > for compile-time configuration).
> > 
> > > It only could work at 1Gps mode.
> > > 
> > > The correct gmac driver should follow (I guess)
> > > drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c
> > > 
> > > If anyone is familiar with it and can help porting, I would be
> > > very grateful.
> > 
> > Have you tried compiling and using that driver? Ideally it should just
> > work, Linux drivers are meant to be portable, by design. And the driver
> > is already enabled by COMPILE_TEST.
> 
> It still needs some work with dwmac-sun8i.c glue layer, eg:
> tx/rx-delay setting, clk & pinmux drivers.
> 
> The patch is just to help people using D1 with GMAC temporarily with
> network function.

It should be marked "DO NOT MERGE" or similar then.

Best regards,
Jernej

> 
> > But I guess you need some extra care to make the non-coherent DMA work?
> > I haven't looked in detail, but are those new CMOs hooked into the
> > generic DMA framework?
> 
> Yes, we have the simliar principle with arm & csky for non-coherent:
>  - Using PTE attributes setting Using PTE attributes to support
> _PAGE_IOREMAP & _PAGE_WRITECOMBINE
>  - Using CMO instructions deal SYNC_DMA_FOR_CPU/DEVICE.
> 
> > Cheers,
> > Andre
> > 
> > > Signed-off-by: Liu Shaohua <liush@allwinnertech.com>
> > > Tested-by: Guo Ren <guoren@kernel.org>
> > > Signed-off-by: Guo Ren <guoren@kernel.org>
> > > Cc: Maxime Ripard <mripard@kernel.org>
> > > Cc: Corentin Labbe <clabbe@baylibre.com>
> > > Cc: Samuel Holland <samuel@sholland.org>
> > > Cc: Icenowy Zheng <icenowy@aosc.io>
> > > Cc: LABBE Corentin <clabbe.montjoie@gmail.com>
> > > Cc: Michael Walle <michael@walle.cc>
> > > Cc: Chen-Yu Tsai <wens@csie.org>
> > > Cc: Maxime Ripard <maxime@cerno.tech>
> > > Cc: Wei Fu <wefu@redhat.com>
> > > Cc: Wei Wu <lazyparser@gmail.com>
> > > Signed-off-by: Guo Ren <guoren@linux.alibaba.com>