From: palmer@sifive.com (Palmer Dabbelt)
To: linux-riscv@lists.infradead.org
Subject: SBI extension proposal
Date: Thu, 01 Nov 2018 19:49:33 -0700 (PDT) [thread overview]
Message-ID: <mhng-dd74f93c-74b1-4701-a73c-339d81aa0bd0@palmer-si-x1c4> (raw)
In-Reply-To: <20181101164205.l2bra3a6kihjpuib@excalibur.cnev.de>
On Thu, 01 Nov 2018 09:42:05 PDT (-0700), merker at debian.org wrote:
> On Thu, Nov 01, 2018 at 09:46:09AM +0000, Richard W.M. Jones wrote:
>> On Thu, Nov 01, 2018 at 03:05:51PM +0530, Anup Patel wrote:
> [...]
>> > > How about putting the version information into device tree
>> > > and use the compatible string? This seems more reliable
>> > > than probing.
>> > > e.g.
>> > > firmware {
>> > > sbi {
>> > > compatible = "riscv,sbi-r0p1", "riscv,sbi-r0p2";
>> > > };
>> > > };
>> >
>> > If it was just DT then I think having this information in DT makes
>> > sense. In future,
>> > we might definitely see some ACPI support in RISC-V too (just like ARM64 world).
>>
>> I agree. Please try not to make things that depend on DT, as it's a
>> Linux-only description which isn't suitable for other OSes and has a
>> poorly defined ABI.
>
> the notion that DT is a "Linux-only" description and not suitable
> for other operating systems isn't correct. Besides being used by
> Linux, device-tree is also used by at least U-Boot, FreeBSD and
> NetBSD. Based on issues in the early days of DT one can surely
> discuss about device-tree ABI stability, but since then a lot of
> effort has been put into making DT ABI-stable, and in my
> experience this effort has been successful. On the other hand I
> have experienced way more ACPI issues on x86-64 hardware than I
> would like to remember, so I tend to assume that in the ACPI
> world also not everything is nice and shining.
I'm treating device tree as a stable interface, at least once it's written down
as a spec (like all our other interfaces). At SiFive we're treating it as the
standard interface for static device discovery, so interface breaks will be a
huge pain.
WARNING: multiple messages have this Message-ID (diff)
From: Palmer Dabbelt <palmer@sifive.com>
To: merker@debian.org
Cc: mark.rutland@arm.com, zong@andestech.com, Damien.LeMoal@wdc.com,
olof.johansson@gmail.com, Andrew Waterman <andrew@sifive.com>,
alankao@andestech.com, anup@brainfault.org,
Paul Walmsley <paul.walmsley@sifive.com>,
rjones@redhat.com, Christoph Hellwig <hch@infradead.org>,
atish.patra@wdc.com, Michael Clark <mjc@sifive.com>,
Arnd Bergmann <arnd@arndb.de>,
philipp@hug.cx, linux-riscv@lists.infradead.org,
abner.chang@hpe.com, vincentc@andestech.com,
David Abdurachmanov <David.Abdurachmanov@cern.ch>
Subject: Re: SBI extension proposal
Date: Thu, 01 Nov 2018 19:49:33 -0700 (PDT) [thread overview]
Message-ID: <mhng-dd74f93c-74b1-4701-a73c-339d81aa0bd0@palmer-si-x1c4> (raw)
Message-ID: <20181102024933.jSZOKv4Cfsut-hhqJkT4H6nVkfgGiM1ld8NMoqkahoc@z> (raw)
In-Reply-To: <20181101164205.l2bra3a6kihjpuib@excalibur.cnev.de>
On Thu, 01 Nov 2018 09:42:05 PDT (-0700), merker@debian.org wrote:
> On Thu, Nov 01, 2018 at 09:46:09AM +0000, Richard W.M. Jones wrote:
>> On Thu, Nov 01, 2018 at 03:05:51PM +0530, Anup Patel wrote:
> [...]
>> > > How about putting the version information into device tree
>> > > and use the compatible string? This seems more reliable
>> > > than probing.
>> > > e.g.
>> > > firmware {
>> > > sbi {
>> > > compatible = "riscv,sbi-r0p1", "riscv,sbi-r0p2";
>> > > };
>> > > };
>> >
>> > If it was just DT then I think having this information in DT makes
>> > sense. In future,
>> > we might definitely see some ACPI support in RISC-V too (just like ARM64 world).
>>
>> I agree. Please try not to make things that depend on DT, as it's a
>> Linux-only description which isn't suitable for other OSes and has a
>> poorly defined ABI.
>
> the notion that DT is a "Linux-only" description and not suitable
> for other operating systems isn't correct. Besides being used by
> Linux, device-tree is also used by at least U-Boot, FreeBSD and
> NetBSD. Based on issues in the early days of DT one can surely
> discuss about device-tree ABI stability, but since then a lot of
> effort has been put into making DT ABI-stable, and in my
> experience this effort has been successful. On the other hand I
> have experienced way more ACPI issues on x86-64 hardware than I
> would like to remember, so I tend to assume that in the ACPI
> world also not everything is nice and shining.
I'm treating device tree as a stable interface, at least once it's written down
as a spec (like all our other interfaces). At SiFive we're treating it as the
standard interface for static device discovery, so interface breaks will be a
huge pain.
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next prev parent reply other threads:[~2018-11-02 2:49 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-31 18:23 SBI extension proposal Atish Patra
2018-10-31 18:23 ` Atish Patra
[not found] ` <CAK-hmcQeiGa3BwnzEVB_dyhFiC7rXHFN-wTsJomg-jAo7a+v3Q@mail.gmail.com>
2018-10-31 19:11 ` Olof Johansson
2018-10-31 19:11 ` Olof Johansson
2018-10-31 20:37 ` Atish Patra
2018-10-31 20:37 ` Atish Patra
2018-11-02 6:31 ` Chang, Abner (HPS SW/FW Technologist)
2018-11-02 6:31 ` Chang, Abner (HPS SW/FW Technologist)
2018-11-02 22:31 ` Atish Patra
2018-11-02 22:31 ` Atish Patra
2018-11-04 14:36 ` Chang, Abner (HPS SW/FW Technologist)
2018-11-04 14:36 ` Chang, Abner (HPS SW/FW Technologist)
[not found] ` <CA+h06zgcyWz7WMbzQxjyc9V5S3CokqSoO1mGOaynJE3uJE5QSg@mail.gmail.com>
2018-11-01 9:35 ` Anup Patel
2018-11-01 9:35 ` Anup Patel
2018-11-01 9:46 ` Richard W.M. Jones
2018-11-01 9:46 ` Richard W.M. Jones
2018-11-01 11:03 ` Philipp Hug
2018-11-01 11:03 ` Philipp Hug
2018-11-01 11:25 ` Richard W.M. Jones
2018-11-01 11:25 ` Richard W.M. Jones
2018-11-01 15:09 ` Atish Patra
2018-11-01 15:09 ` Atish Patra
2018-11-02 3:17 ` Olof Johansson
2018-11-02 3:17 ` Olof Johansson
2018-11-01 16:42 ` Karsten Merker
2018-11-02 2:49 ` Palmer Dabbelt [this message]
2018-11-02 2:49 ` Palmer Dabbelt
2018-11-02 3:27 ` Anup Patel
2018-11-02 3:27 ` Anup Patel
2018-11-02 4:29 ` Chang, Abner (HPS SW/FW Technologist)
2018-11-02 4:29 ` Chang, Abner (HPS SW/FW Technologist)
2018-11-02 15:24 ` Nick Kossifidis
2018-11-02 15:24 ` Nick Kossifidis
2018-11-02 23:12 ` Atish Patra
2018-11-02 23:12 ` Atish Patra
2018-11-02 23:45 ` Nick Kossifidis
2018-11-02 23:45 ` Nick Kossifidis
2018-11-03 0:00 ` Atish Patra
2018-11-03 0:00 ` Atish Patra
2018-11-05 13:50 ` Nick Kossifidis
2018-11-05 13:50 ` Nick Kossifidis
2018-11-05 18:51 ` Atish Patra
2018-11-05 18:51 ` Atish Patra
2018-11-06 1:55 ` Zong Li
2018-11-06 1:55 ` Zong Li
2018-11-09 21:47 ` Atish Patra
2018-11-09 21:47 ` Atish Patra
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