From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Anholt Subject: Re: BCM2836 (Raspberry Pi 2) port Date: Wed, 13 May 2015 10:46:24 -0700 Message-ID: <87wq0c4bgv.fsf@eliezer.anholt.net> References: <1429639796-2169-1-git-send-email-eric@anholt.net> <4137213.WVJY1et48u@kongar> <55516738.306@wwwdotorg.org> <1701192.WcfjCoBWQN@kongar> <55522468.3050606@wwwdotorg.org> <87d2254s6y.fsf@eliezer.anholt.net> <555278BA.50903@wwwdotorg.org> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha512; protocol="application/pgp-signature" Return-path: In-Reply-To: <555278BA.50903-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Stephen Warren , Alexander Stein Cc: linux-rpi-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: devicetree@vger.kernel.org --=-=-= Content-Type: text/plain Content-Transfer-Encoding: quoted-printable Stephen Warren writes: > On 05/12/2015 11:32 AM, Eric Anholt wrote: >> Stephen Warren writes: >> >>> On 05/12/2015 09:39 AM, Alexander Stein wrote: >>>> On Monday 11 May 2015, 20:36:40 wrote Stephen Warren: >>>>> On 05/08/2015 10:14 AM, Alexander Stein wrote: >>>>>> On Thursday 23 April 2015, 22:25:08 wrote Stephen Warren: >>>>>>>> Hit any key to stop autoboot: 0 >>>>>>>> U-Boot> setenv fdt_high fffffff >>>>>> >>>>>> Any specific reason to set fdt_high to fffffff? >>>>> >>>>> Yes, it prevents U-Boot's annoying habit of moving the DTB from where= it >>>>> was loaded to some other place. This was especially important in this >>>>> case since I was trying to find out exactly which piece of RAM being >>>>> over-written caused the issues I was seeing. >>>> >>>> Shouldn't this then be part of the default raspberry (2 only?) environ= ment? >>> >>> Eventually yes. So far, nobody seems to know which areas of RAM are >>> off-limits (presumably since the RAM is used as a CPU1..3 pen), so I was >>> experimenting to try and find that out. >> >> If I'm reading this right, the CPU1-3 pen is in the bottom 8k of memory >> (actually much less than 8k). > > Hmm. I wondered if that was the case. I don't think anything I was doing= =20 > in U-Boot /should/ touch those pages, but there have been bugs before=20 > where some pointer was left at NULL, and some DM (U-Boot Device Model)=20 > code ended up putting structures in page 0 by mistake. Perhaps something= =20 > like that has resurfaced. I'll try to find time to diff page 0=20 > before/after various U-Boot operations, and see if it's getting modified.= .. How about on the Linux side? What's reserving that memory for us, if anything? Weird things happen if I put "ARM: bcm2836: Add a DT binding for the ARM local registers." and "ARM: bcm2835: Use a syscon regmap to set up timer frequency." before the SMP support in the bcm2836-smp tree (init crashes). --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBCgAGBQJVU43wAAoJELXWKTbR/J7o7Y0QAJwKymFmvnfmtuXF8ZFXMyfO 1SNFeozT+CjjVL+wiA7IfrkEcAdYZdQteab+bt7B6MvpO+8t4oDJOrD59rU/6fCb GUm1NtNNvnrTvTF0ioAsVClgxKTRyyYxHRG1SE5C28OZhnu8g689T4NuywWyZCI0 2qgiQMQ2YqLMeV0Yrpp1atwJrNy/JR+XcyR7HYQk8GCJvWBhcUWKOVLwMzfeyKsh TJiFjVqSNQAEcs7kI7Nmc37SKig8XyO7zMlBNFmlfhXkT00vA1VVi5sxXcRnua/Q HY60M8QVmAq4TxYvWt/KbdjBXx+cr0fuuIkEf7zu8FJaBWnSHMR4Z2n3He3H4dr3 Rxxz13FcScZy7+W/eYf7e8VZv606EUiJ3kpFLjDkBZ9ZBtopZF+LVwNOm7XJGAYF tfRDa+hXoRBP+QNPw+jl0vRK/ieEhHUhkbsRHcnTHLmNwg7X6Kamk769nkynM8hM RauCP25spYPBJoqktGRi7nr1rm3Yf/L1p0bDa51HHdDnPVRQ1ok9VHn9SAZn6mTl 0LHk4t07AY8rXqgOw4w0zC3VuUaqHJjLlFN9IMf8rnkVhQsO1e/aaVPTLWMBfUkC GluFvkNYa0vsKjLZFDq5Eh+IOGINULCDO9YALxijUwRBxS3yhlAu2YoYdExcGfmV qsUYgEjQ0ojga26qOshO =Uply -----END PGP SIGNATURE----- --=-=-=-- -- 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