[PATCH v5 12/14] riscv: sifive: fu540: enable all cache ways from u-boot proper

[Anup Patel]

On Fri, Mar 13, 2020 at 3:52 PM Bin Meng <bmeng.cn at gmail.com> wrote:
>
> Hi Anup,
>
> On Fri, Mar 13, 2020 at 6:02 PM Anup Patel <anup at brainfault.org> wrote:
> >
> > On Fri, Mar 13, 2020 at 2:31 PM Bin Meng <bmeng.cn at gmail.com> wrote:
> > >
> > > On Wed, Mar 11, 2020 at 3:04 PM Pragnesh Patel
> > > <pragnesh.patel at sifive.com> wrote:
> > > >
> > > > Enable all cache ways from u-boot proper.
> > >
> > > U-Boot
> > >
> > > >
> > > > Signed-off-by: Pragnesh Patel <pragnesh.patel at sifive.com>
> > > > ---
> > > >  board/sifive/fu540/Makefile |  1 +
> > > >  board/sifive/fu540/cache.c  | 20 ++++++++++++++++++++
> > > >  board/sifive/fu540/cache.h  | 13 +++++++++++++
> > > >  board/sifive/fu540/fu540.c  |  6 ++++--
> > > >  4 files changed, 38 insertions(+), 2 deletions(-)
> > > >  create mode 100644 board/sifive/fu540/cache.c
> > > >  create mode 100644 board/sifive/fu540/cache.h
> > > >
> > > > diff --git a/board/sifive/fu540/Makefile b/board/sifive/fu540/Makefile
> > > > index b05e2f5807..3b867bbd89 100644
> > > > --- a/board/sifive/fu540/Makefile
> > > > +++ b/board/sifive/fu540/Makefile
> > > > @@ -3,6 +3,7 @@
> > > >  # Copyright (c) 2019 Western Digital Corporation or its affiliates.
> > > >
> > > >  obj-y  += fu540.o
> > > > +obj-y  += cache.o
> > > >
> > > >  ifdef CONFIG_SPL_BUILD
> > > >  obj-y += spl.o
> > > > diff --git a/board/sifive/fu540/cache.c b/board/sifive/fu540/cache.c
> > > > new file mode 100644
> > > > index 0000000000..a0bcd2ba48
> > > > --- /dev/null
> > > > +++ b/board/sifive/fu540/cache.c
> > >
> > > This should be put into arch/riscv/cpu/fu540/cache.c
> > >
> > > > @@ -0,0 +1,20 @@
> > > > +// SPDX-License-Identifier: GPL-2.0+
> > > > +/*
> > > > + * Copyright (c) 2019 SiFive, Inc
> > > > + */
> > > > +#include <asm/io.h>
> > > > +
> > > > +/* Register offsets */
> > > > +#define CACHE_ENABLE           0x008
> > > > +
> > > > +/* Enable ways; allow cache to use these ways */
> > > > +void cache_enable_ways(u64 base_addr, u8 value)
> > > > +{
> > > > +       volatile u32 *enable = (volatile u32 *)(base_addr +
> > > > +                                         CACHE_ENABLE);
> > > > +       /* memory barrier */
> > > > +       mb();
> > > > +       (*enable) = value;
> > > > +       /* memory barrier */
> > > > +       mb();
> > > > +}
> > > > diff --git a/board/sifive/fu540/cache.h b/board/sifive/fu540/cache.h
> > > > new file mode 100644
> > > > index 0000000000..425124a23b
> > > > --- /dev/null
> > > > +++ b/board/sifive/fu540/cache.h
> > >
> > > arch/riscv/include/asm/arch-fu540/cache.h
> >
> > Let's not entire FU540 directory under arch/riscv/cpu directory
> > just to have cache functions. The arch/riscv/cpu/generic is perfectly
> > suitable for FU540.
>
> I doubt arch/riscv/cpu/generic can be generic if we consider U-Boot
> SPL phase. It can be generic for S-mode U-Boot though.

Its really very easy to do. We are already doing this in Xvisor.

As an example, of DT based operations in a generic board support refer:
https://github.com/avpatel/xvisor-next/blob/master/arch/arm/board/generic/brd_main.c
https://github.com/avpatel/xvisor-next/blob/master/arch/arm/board/generic/foundation-v8.c

Using the above approach, we are able to boot same Xvisor ARM/ARM64
binary on multiple boards.

>
> >
> > If we re-use arch/riscv/cpu/generic as-much as possible then
> > arch/riscv will be easy to maintain in future.
> >
> > We can add arch/riscv/cpu/generic/cache.c which will do
> > things FU540 specific based on "#ifdef" or "DT compatible string".
> >
>
> Regards,
> Bin

Regards,
Anup