Re: [PATCH v4] ARM: boot: Obtain start of physical memory from DTB

From: Dmitry Osipenko <digetx@gmail.com>
To: "Geert Uytterhoeven" <geert+renesas@glider.be>,
	"Russell King" <linux@armlinux.org.uk>,
	"Nicolas Pitre" <nico@fluxnic.net>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"Eric Miao" <eric.miao@nvidia.com>,
	"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: linux-renesas-soc@vger.kernel.org,
	Chris Brandt <chris.brandt@renesas.com>,
	"linux-tegra@vger.kernel.org" <linux-tegra@vger.kernel.org>,
	Ard Biesheuvel <ardb@kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	Marek Szyprowski <m.szyprowski@samsung.com>
Subject: Re: [PATCH v4] ARM: boot: Obtain start of physical memory from DTB
Date: Fri, 20 Mar 2020 18:30:17 +0300	[thread overview]
Message-ID: <df884591-8af9-3b66-f09d-f1a4d6c6579a@gmail.com> (raw)
In-Reply-To: <20200320144348.12865-1-geert+renesas@glider.be>

20.03.2020 17:43, Geert Uytterhoeven пишет:
> Currently, the start address of physical memory is obtained by masking
> the program counter with a fixed mask of 0xf8000000.  This mask value
> was chosen as a balance between the requirements of different platforms.
> However, this does require that the start address of physical memory is
> a multiple of 128 MiB, precluding booting Linux on platforms where this
> requirement is not fulfilled.
> 
> Fix this limitation by obtaining the start address from the DTB instead,
> if available (either explicitly passed, or appended to the kernel).
> Fall back to the traditional method when needed.
> 
> This allows to boot Linux on r7s9210/rza2mevb using the 64 MiB of SDRAM
> on the RZA2MEVB sub board, which is located at 0x0C000000 (CS3 space),
> i.e. not at a multiple of 128 MiB.
> 
> Suggested-by: Nicolas Pitre <nico@fluxnic.net>
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> Reviewed-by: Nicolas Pitre <nico@fluxnic.net>
> Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
> ---
> v4:
>   - Fix stack location after commit 184bf653a7a452c1 ("ARM:
>     decompressor: factor out routine to obtain the inflated image
>     size"),
> 
> v3:
>   - Add Reviewed-by,
>   - Fix ATAGs with appended DTB,
>   - Add Tested-by,
> 
> v2:
>   - Use "cmp r0, #-1", instead of "cmn r0, #1",
>   - Add missing stack setup,
>   - Support appended DTB.
> ---
>  arch/arm/boot/compressed/Makefile            |  6 ++-
>  arch/arm/boot/compressed/fdt_get_mem_start.c | 52 +++++++++++++++++++
>  arch/arm/boot/compressed/head.S              | 54 +++++++++++++++++++-
>  3 files changed, 110 insertions(+), 2 deletions(-)
>  create mode 100644 arch/arm/boot/compressed/fdt_get_mem_start.c

Thank you very much! It works!

Tested-by: Dmitry Osipenko <digetx@gmail.com>

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