From: arnd@arndb.de (Arnd Bergmann)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC 6/7] ARM: vf610m4: HACK: get dtb pointer from SRC_GPR3
Date: Sun, 12 Oct 2014 21:00:52 +0200 [thread overview]
Message-ID: <1815119.sje1JPFb29@wuerfel> (raw)
In-Reply-To: <2bdc44912522eb02db2e4612738fe9f0545b36d9.1413136383.git.stefan@agner.ch>
On Sunday 12 October 2014 20:14:00 Stefan Agner wrote:
> Get DTB pointer (located in r2) from SRC_GPR3 (argument register
> for secondary core)
>
> Signed-off-by: Stefan Agner <stefan@agner.ch>
> ---
> This is clearly a hack but it works around the need of a boot loader
> on the Cortex-M4. I guess there is no way neither its acceptable to
> do this on machine level..? But then, this can also be done with a
> minimal boot loader loaded just in front of the kernel by the m4boot
> utility.
>
How do you actually enter the kernel on the m4? Do you use a
decompressor or XIP_KERNEL at the moment? There are probably
lots of ways to do this, my first idea would be to have a vybrid
specific boot wrapper that consists of just a few assembly
instructions to set up the initial environment from wherever
it gets started.
Arnd
WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>
To: Stefan Agner <stefan-XLVq0VzYD2Y@public.gmane.org>
Cc: shawn.guo-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org,
kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org,
u.kleine-koenig-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org,
olof-nZhT3qVonbNeoWH0uzbU5w@public.gmane.org,
marcel-mitwqZ+T+m9Wk0Htik3J/w@public.gmane.org,
linux-lFZ/pmaqli7XmaaqVzeoHQ@public.gmane.org,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [RFC 6/7] ARM: vf610m4: HACK: get dtb pointer from SRC_GPR3
Date: Sun, 12 Oct 2014 21:00:52 +0200 [thread overview]
Message-ID: <1815119.sje1JPFb29@wuerfel> (raw)
In-Reply-To: <2bdc44912522eb02db2e4612738fe9f0545b36d9.1413136383.git.stefan-XLVq0VzYD2Y@public.gmane.org>
On Sunday 12 October 2014 20:14:00 Stefan Agner wrote:
> Get DTB pointer (located in r2) from SRC_GPR3 (argument register
> for secondary core)
>
> Signed-off-by: Stefan Agner <stefan-XLVq0VzYD2Y@public.gmane.org>
> ---
> This is clearly a hack but it works around the need of a boot loader
> on the Cortex-M4. I guess there is no way neither its acceptable to
> do this on machine level..? But then, this can also be done with a
> minimal boot loader loaded just in front of the kernel by the m4boot
> utility.
>
How do you actually enter the kernel on the m4? Do you use a
decompressor or XIP_KERNEL at the moment? There are probably
lots of ways to do this, my first idea would be to have a vybrid
specific boot wrapper that consists of just a few assembly
instructions to set up the initial environment from wherever
it gets started.
Arnd
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next prev parent reply other threads:[~2014-10-12 19:00 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-12 18:13 [RFC 0/7] ARM: vf610m4: Add Vybrid Cortex-M4 support Stefan Agner
2014-10-12 18:13 ` Stefan Agner
2014-10-12 18:13 ` [RFC 1/7] ARM: vf610: add low level debug support for !MMU Stefan Agner
2014-10-12 18:13 ` Stefan Agner
2014-10-12 18:48 ` Arnd Bergmann
2014-10-12 18:48 ` Arnd Bergmann
2014-10-13 9:26 ` Stefan Agner
2014-10-13 9:26 ` Stefan Agner
2014-10-12 18:13 ` [RFC 2/7] clocksource: add dependencies for Vybrid pit clocksource Stefan Agner
2014-10-12 18:13 ` Stefan Agner
2014-10-12 18:18 ` Uwe Kleine-König
2014-10-12 18:18 ` Uwe Kleine-König
2014-10-13 9:46 ` Stefan Agner
2014-10-13 9:46 ` Stefan Agner
2014-10-13 10:57 ` Uwe Kleine-König
2014-10-13 10:57 ` Uwe Kleine-König
2014-10-12 18:13 ` [RFC 3/7] ARM: vf610m4: add new machine and SoC for Vybrid on Cortex-M4 Stefan Agner
2014-10-12 18:13 ` Stefan Agner
2014-10-12 18:51 ` Arnd Bergmann
2014-10-12 18:51 ` Arnd Bergmann
2014-10-13 10:03 ` Stefan Agner
2014-10-13 10:03 ` Stefan Agner
2014-10-13 10:57 ` Arnd Bergmann
2014-10-13 10:57 ` Arnd Bergmann
2014-10-12 18:13 ` [RFC 4/7] ARM: dts: add support for Vybrid running " Stefan Agner
2014-10-12 18:13 ` Stefan Agner
2014-10-12 18:56 ` Arnd Bergmann
2014-10-12 18:56 ` Arnd Bergmann
2014-10-13 10:41 ` Stefan Agner
2014-10-13 10:41 ` Stefan Agner
2014-10-13 10:32 ` Mark Rutland
2014-10-13 10:32 ` Mark Rutland
2014-10-13 11:08 ` Stefan Agner
2014-10-13 11:08 ` Stefan Agner
2014-10-13 11:24 ` Arnd Bergmann
2014-10-13 11:24 ` Arnd Bergmann
2014-10-13 16:11 ` Stefan Agner
2014-10-13 16:11 ` Stefan Agner
2014-10-13 19:54 ` Arnd Bergmann
2014-10-13 19:54 ` Arnd Bergmann
2014-10-13 21:20 ` Stefan Agner
2014-10-13 21:20 ` Stefan Agner
2014-10-14 10:01 ` Arnd Bergmann
2014-10-14 10:01 ` Arnd Bergmann
2014-10-12 18:13 ` [RFC 5/7] irqchip: nvic: increase number of external interrupts to 112 Stefan Agner
2014-10-12 18:13 ` Stefan Agner
2014-10-12 18:14 ` [RFC 6/7] ARM: vf610m4: HACK: get dtb pointer from SRC_GPR3 Stefan Agner
2014-10-12 18:14 ` Stefan Agner
2014-10-12 19:00 ` Arnd Bergmann [this message]
2014-10-12 19:00 ` Arnd Bergmann
2014-10-13 10:10 ` Stefan Agner
2014-10-13 10:10 ` Stefan Agner
2014-10-12 18:14 ` [RFC 7/7] ARM: vf610m4: add defconfig for Linux on Vybrids Cortex-M4 Stefan Agner
2014-10-12 18:14 ` Stefan Agner
2014-11-28 14:17 ` [RFC 0/7] ARM: vf610m4: Add Vybrid Cortex-M4 support Andreas Färber
2014-11-28 14:17 ` Andreas Färber
2014-11-28 16:00 ` Stefan Agner
2014-11-28 16:00 ` Stefan Agner
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