From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [RFC 6/7] ARM: vf610m4: HACK: get dtb pointer from SRC_GPR3 Date: Sun, 12 Oct 2014 21:00:52 +0200 Message-ID: <1815119.sje1JPFb29@wuerfel> References: <2bdc44912522eb02db2e4612738fe9f0545b36d9.1413136383.git.stefan@agner.ch> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: <2bdc44912522eb02db2e4612738fe9f0545b36d9.1413136383.git.stefan-XLVq0VzYD2Y@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Stefan Agner 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 List-Id: devicetree@vger.kernel.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 > --- > 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 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html