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Date:   Thu, 22 Jun 2023 18:41:13 +0100
From:   Conor Dooley <conor@kernel.org>
To:     Alexandre Ghiti <alexghiti@rivosinc.com>
Cc:     Andrew Jones <ajones@ventanamicro.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Conor Dooley <conor.dooley@microchip.com>,
        Sunil V L <sunilvl@ventanamicro.com>,
        Song Shuai <songshuaishuai@tinylab.org>,
        linux-doc@vger.kernel.org, linux-riscv@lists.infradead.org,
        linux-kernel@vger.kernel.org,
        =?iso-8859-1?Q?Bj=F6rn_T=F6pel?= <bjorn@rivosinc.com>
Subject: Re: [PATCH v2 2/3] Documentation: riscv: Add early boot document
Message-ID: <20230622-clone-overfed-21ec0886e904@spud>
References: <20230621072234.9900-1-alexghiti@rivosinc.com>
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 <20230622-4af59422f118ea634836d351@orel>
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On Thu, Jun 22, 2023 at 07:32:23PM +0200, Alexandre Ghiti wrote:
> On Thu, Jun 22, 2023 at 7:24=E2=80=AFPM Andrew Jones <ajones@ventanamicro=
=2Ecom> wrote:
> >
> > On Wed, Jun 21, 2023 at 02:19:50PM +0200, Andrew Jones wrote:
> > > On Wed, Jun 21, 2023 at 09:22:33AM +0200, Alexandre Ghiti wrote:
> > ...
> > > > +Hardware description
> > > > +--------------------
> > > > +
> > > > +The firmware can pass either a devicetree or ACPI tables to the RI=
SC-V kernel.
> > > > +
> > > > +The devicetree is either passed directly to the kernel from the pr=
evious stage
> > > > +using the `$a1` register, or when booting with UEFI, it can be pas=
sed using the
> > > > +EFI configuration table.
> > > > +
> > > > +The ACPI tables are passed to the kernel using the EFI configurati=
on table. In
> > > > +this case, a tiny devicetree is still created by the EFI stub. Ple=
ase refer to
> > > > +"EFI stub and devicetree" tree section below for details about thi=
s devicetree.
> > >                              ^ redundant 'tree' here
> > >
> >
> > Can whoever applies this drop this 'tree' I pointed while applying?
>=20
> Yes, sorry: @Conor Dooley give me the overly long lines you wanted me
> to break and I'll send a v3, it won't take much time and I'll fix this
> too!

Look, I said it was pure pedantry on my part, and not something that
helps with understanding. You've been warned!

diff --git a/Documentation/riscv/boot.rst b/Documentation/riscv/boot.rst
index 019ee818686d..a52793fd9f6c 100644
--- a/Documentation/riscv/boot.rst
+++ b/Documentation/riscv/boot.rst
@@ -143,11 +143,12 @@ be carefully examined.
 Device-tree mapping via fixmap
 ------------------------------
=20
-The RISC-V kernel uses the fixmap region to map the devicetree because the
-devicetree virtual mapping must remain the same between :c:func:`setup_vm`=
 and
-:c:func:`setup_vm_final` calls since the :c:var:`reserved_mem` array is
-initialized with virtual addresses established by :c:func:`setup_vm` and u=
sed
-with the mapping established by :c:func:`setup_vm_final`.
+
+As the :c:var:`reserved_mem` array is initialized with virtual addresses
+established by :c:func:`setup_vm`, and used with the mapping established by
+:c:func:`setup_vm_final`, the RISC-V kernel uses the fixmap region to map =
the
+devicetree. This ensures that the same virtual mapping is used by both
+functions.
=20
 Pre-MMU execution
 -----------------

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