[PATCH 1/2] lib: utils: Implement "64bit-mmio" property parsing

[Anup Patel]

> -----Original Message-----
> From: Jessica Clarke <jrtc27 at jrtc27.com>
> Sent: 17 April 2021 17:16
> To: guoren at kernel.org
> Cc: Alistair Francis <Alistair.Francis at wdc.com>; Anup Patel
> <anup at brainfault.org>; OpenSBI <opensbi at lists.infradead.org>; Guo Ren
> <guoren at linux.alibaba.com>; Anup Patel <Anup.Patel at wdc.com>; Xiang W
> <wxjstz at 126.com>
> Subject: Re: [PATCH 1/2] lib: utils: Implement "64bit-mmio" property parsing
> 
> On 17 Apr 2021, at 12:41, Jessica Clarke <jrtc27 at jrtc27.com> wrote:
> >
> > On 13 Apr 2021, at 04:44, guoren at kernel.org wrote:
> >>
> >> From: Guo Ren <guoren at linux.alibaba.com>
> >>
> >> Figure out CLINT has_64bit_mmio from DT node and using antonym for
> >> compatibility.
> >>
> >> Signed-off-by: Guo Ren <guoren at linux.alibaba.com>
> >> Cc: Anup Patel <anup.patel at wdc.com>
> >> Cc: Xiang W <wxjstz at 126.com>
> >> ---
> >> lib/utils/fdt/fdt_helper.c | 3 ++-
> >> 1 file changed, 2 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/lib/utils/fdt/fdt_helper.c b/lib/utils/fdt/fdt_helper.c
> >> index bf19ff9..909de01 100644
> >> --- a/lib/utils/fdt/fdt_helper.c
> >> +++ b/lib/utils/fdt/fdt_helper.c
> >> @@ -442,8 +442,9 @@ int fdt_parse_clint_node(void *fdt, int
> nodeoffset, bool for_timer,
> >> 	if (clint->hart_count < count)
> >> 		clint->hart_count = count;
> >>
> >> -	/* TODO: We should figure-out CLINT has_64bit_mmio from DT node
> */
> >> 	clint->has_64bit_mmio = TRUE;
> >> +	if (fdt_getprop(fdt, nodeoffset, "clint,has-no-64bit-mmio",
> >> +&count))
> >
> > I do not see this specified in clint.yaml.
> 
> Also, the RISC-V privileged is very clear:
> 
> > For RV64, naturally aligned 64-bit memory accesses to the mtime and
> > mtimecmp registers are atomic.
> 
> So I would say your CLINT violates the spec and thus should not claim to be a
> RISC-V or SiFive-compatible CLINT.

There is no CLINT spec maintained by RISC-V international.

All implementation have SiFive compatible CLINT or some variant of it.

Regards,
Anup