Date: Tue, 17 Jun 2014 08:10:00 +0200 From: Michael Tuexen <tuexen@freebsd.org> To: Jia-Shiun Li <jiashiun@gmail.com> Cc: "freebsd-arm@freebsd.org" <freebsd-arm@freebsd.org>, Andreas Schwarz <freebsd.asc@strcmp.org>, Ian Lepore <ian@freebsd.org> Subject: Re: FreeBSD doesn't boot anymore on RPi Message-ID: <D8F54FDE-FF4E-4107-B293-8BDC28A0E90B@freebsd.org> In-Reply-To: <CAHNYxxM9Yy0w0H9m3vMJ1ToeNkaW91%2B1unHVWqR1MG%2Bn1RsC3g@mail.gmail.com> References: <D8D9CAB0-A33C-45C5-AD17-E7C23F5309C8@fh-muenster.de> <44921fa0c7.323fafd0@mail.schwarzes.net> <A4EE9C49-DF7E-458F-9A69-C1B75FFA47CA@freebsd.org> <CAHNYxxM9Yy0w0H9m3vMJ1ToeNkaW91%2B1unHVWqR1MG%2Bn1RsC3g@mail.gmail.com>
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On 17 Jun 2014, at 06:44, Jia-Shiun Li <jiashiun@gmail.com> wrote: > On Mon, Jun 16, 2014 at 1:53 PM, Michael Tuexen <tuexen@freebsd.org> wrote: >> On 16 Jun 2014, at 03:04, Andreas Schwarz <freebsd.asc@strcmp.org> wrote: >>> On 21.05.14, Michael Tuexen wrote: >>> >>> Hi all, >>> >>>> I just built r266500 and when booting that on a Raspberry Pi the booting stalls >>>> after displaying Kernel args: (null). >>> >>> I run still in this problem, the last kernel which was working for me is r265403. Is this >>> a know problem? >> Yes, it is known. There were two problems, one is fixed now. The other problem >> is currently been worked on. Right now, you need to revert r266083 and should >> get a working kernel. If not, please let us know. >> > > adding ian@ and markm@. > > > Hi, > > looks ARM1176, aka RPi, has different register location for > performance counters. > > r266083 uses PMC registers defined at c9:c12~c14 of CP15. The location > is true for Cortex-A8[1] onward. For ARM11 which predated A8, however, > these registers are located at c15:c12[2]. c9:c12~c14 are undefined on > ARM1176. > > According to ARMARM, pre-ARM11 cores do not have PMC. So they must > have decided the debut location of PMC was not suitable anymore , and > moved to c9 afterward. > > For RPi I think it is simpler to exclude ARM11 in original code for > now. After making sure PMC registers on ARM11, despite different > location, are still suitable for the purpose, it can have dedicated > handling different from other cores. > > Other cores like pj4b and Krait may need additional check. > > [1] Ch.3.2.1 of Cortex-A8 TRM r3p2, > http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0344k/ch03s02s01.html > [2] Ch.3.2.1 of ARM1176jz-s TRM r0p7, > http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0333h/ch03s02s01.html Please have a look at the thread 'Re: svn commit: r266083 - in head/sys/arm: arm include' on current@freebsd.org. The patches being discussed there allow the RPI. Basically they use different registers on different platforms as you write. Best regards Michael > > -Jia-Shiun. >help
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