From: David Gibson <david@gibson.dropbear.id.au>
To: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Peter Maydell <peter.maydell@linaro.org>,
qemu-riscv@nongnu.org, palmer@sifive.com, qemu-devel@nongnu.org,
Christoph Hellwig <hch@infradead.org>,
alistair23@gmail.com
Subject: Re: [PATCH] RISC-V: virt: This is a "sifive,test1" test finisher
Date: Sun, 10 Nov 2019 21:10:33 +0000 [thread overview]
Message-ID: <20191110211033.GU2461@umbus.Home> (raw)
In-Reply-To: <mhng-3242a5ea-9d0c-49fb-bcf6-d8482328b272@palmer-si-x1c4>
[-- Attachment #1: Type: text/plain, Size: 3340 bytes --]
On Fri, Nov 08, 2019 at 10:13:16AM -0800, Palmer Dabbelt wrote:
> On Fri, 08 Nov 2019 10:04:47 PST (-0800), Peter Maydell wrote:
> > On Fri, 8 Nov 2019 at 17:15, Alistair Francis <alistair23@gmail.com> wrote:
> > >
> > > On Fri, Nov 8, 2019 at 9:05 AM Palmer Dabbelt <palmer@sifive.com> wrote:
> > > >
> > > > The test finisher implements the reset command, which means it's a
> > > > "sifive,test1" device. This is a backwards compatible change, so it's
> > > > also a "sifive,test0" device. I copied the odd idiom for adding a
> > > > two-string compatible field from the ARM virt board.
> > > >
> > > > Fixes: 9a2551ed6f ("riscv: sifive_test: Add reset functionality")
> > > > Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
> > > > Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
> > > > ---
> > > > hw/riscv/virt.c | 5 ++++-
> > > > 1 file changed, 4 insertions(+), 1 deletion(-)
> > > >
> > > > diff --git a/hw/riscv/virt.c b/hw/riscv/virt.c
> > > > index 23f340df19..74f2dce81c 100644
> > > > --- a/hw/riscv/virt.c
> > > > +++ b/hw/riscv/virt.c
> > > > @@ -359,7 +359,10 @@ static void create_fdt(RISCVVirtState *s, const struct MemmapEntry *memmap,
> > > > nodename = g_strdup_printf("/test@%lx",
> > > > (long)memmap[VIRT_TEST].base);
> > > > qemu_fdt_add_subnode(fdt, nodename);
> > > > - qemu_fdt_setprop_string(fdt, nodename, "compatible", "sifive,test0");
> > > > + {
> > > > + const char compat[] = "sifive,test1\0sifive,test0";
> > >
> > > Does this really work? Why not use qemu_fdt_setprop_cells()?
> > >
> > > Alistair
> > >
> > > > + qemu_fdt_setprop(fdt, nodename, "compatible", compat, sizeof(compat));
> > > > + }
> >
> > qemu_fdt_setprop_cells() is for "set this property to
> > contain this list of 32-bit integers" (and it does a byteswap
> > of each 32-bit value from host to BE). That's not what
> > you want for a string (or a string list, which is what
> > we have here).
> >
> > Cc'ing David Gibson who's our device tree expert to see if there's
> > a nicer way to write this. Oddly, given that it's used in the
> > ubiquitous 'compatible' prop, the dtc Documentation/manual.txt
> > doesn't say anything about properties being able to be
> > 'string lists', only 'strings', '32 bit numbers', 'lists of
> > 32-bit numbers' and 'byte sequences'. You have to dig through
> > the header file comments to deduce that a string list is
> > represented by a string with embedded NULs separating
> > each list item.
>
> I copied this from hw/arm/virt.c, but messed up. There they use
>
> const char compat[] = "arm,armv8-timer\0arm,armv7-timer";
> qemu_fdt_setprop(vms->fdt, "/timer", "compatible",
> compat, sizeof(compat));
I'm not sure what you're saying is messed up. AFAICT, this matches
the code you have above, and both should be correct.
> I'll send a v2, but I'd be happy to add some sort of setprop_stringlist
> function. Maybe we just indicate the length with two '\0's? IIRC that's
> how other similar-looking data structures are encoded.
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
next prev parent reply other threads:[~2019-11-10 21:12 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-07 22:25 [PATCH] RISC-V: virt: This is a "sifive,test1" test finisher Palmer Dabbelt
2019-11-08 17:13 ` Alistair Francis
2019-11-08 18:04 ` Peter Maydell
2019-11-08 18:13 ` Palmer Dabbelt
2019-11-10 21:10 ` David Gibson [this message]
2019-11-21 2:40 ` Palmer Dabbelt
2019-11-21 18:55 ` Alistair Francis
2019-11-21 19:06 ` Palmer Dabbelt
2019-11-10 21:09 ` David Gibson
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20191110211033.GU2461@umbus.Home \
--to=david@gibson.dropbear.id.au \
--cc=alistair23@gmail.com \
--cc=hch@infradead.org \
--cc=palmer@dabbelt.com \
--cc=palmer@sifive.com \
--cc=peter.maydell@linaro.org \
--cc=qemu-devel@nongnu.org \
--cc=qemu-riscv@nongnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).