From: Stafford Horne <shorne@gmail.com>
To: "Gabriel L. Somlo" <gsomlo@gmail.com>
Cc: Joel Stanley <joel@jms.id.au>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Karol Gugala <kgugala@antmicro.com>,
Mateusz Holenko <mholenko@antmicro.com>,
pczarnecki@internships.antmicro.com,
David Gow <davidgow@google.com>,
Florent Kermarrec <florent@enjoy-digital.fr>
Subject: Re: [PATCH v2] drivers/soc/litex: remove 8-bit subregister option
Date: Fri, 11 Jun 2021 04:45:48 +0900 [thread overview]
Message-ID: <YMJr7DdTZevH/E8K@antec> (raw)
In-Reply-To: <20210527031736.GA491539@crash.ini.cmu.edu>
On Wed, May 26, 2021 at 11:17:36PM -0400, Gabriel L. Somlo wrote:
> On Thu, May 27, 2021 at 02:12:40AM +0000, Joel Stanley wrote:
> > On Wed, 26 May 2021 at 10:55, Gabriel Somlo <gsomlo@gmail.com> wrote:
> > >
> > > Since upstream LiteX recommends that Linux support be limited to
> > > designs configured with 32-bit CSR subregisters (see commit a2b71fde
> > > in upstream LiteX, https://github.com/enjoy-digital/litex), remove
> > > the option to select 8-bit subregisters, significantly reducing the
> > > complexity of LiteX CSR (MMIO register) accessor methods.
> > >
> > > NOTE: for details on the underlying mechanics of LiteX CSR registers,
> > > see https://github.com/enjoy-digital/litex/wiki/CSR-Bus or the original
> > > LiteX accessors (litex/soc/software/include/hw/common.h in the upstream
> > > repository).
> > >
> > > Signed-off-by: Gabriel Somlo <gsomlo@gmail.com>
> >
> > I like how this simplifies things.
> >
> > Reviewed-by: Joel Stanley <joel@jms.id.au>
>
> Thanks!
>
> > With this change, is there any need to keep the litex acessors around?
> >
> > There's the 64 bit case, but we don't have any 64 bit CSR registers do we?
>
> Off the top of my head, the LiteSDcard driver uses 64-bit CSR writes:
> https://github.com/litex-hub/linux/blob/litex-rebase/drivers/mmc/host/litex_mmc.c#L403
> and
> https://github.com/litex-hub/linux/blob/litex-rebase/drivers/mmc/host/litex_mmc.c#L421
>
> These are both DMA base-address registers that support rv64*.
>
I have pushed version to to for-next which should show up in linux-next today or
next week.
-Stafford
prev parent reply other threads:[~2021-06-10 19:47 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-26 10:51 [PATCH v2] drivers/soc/litex: remove 8-bit subregister option Gabriel Somlo
2021-05-27 2:12 ` Joel Stanley
2021-05-27 3:17 ` Gabriel L. Somlo
2021-06-10 19:45 ` Stafford Horne [this message]
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