Date: Sun, 10 Feb 2013 09:02:53 -0800 From: Adrian Chadd <adrian@freebsd.org> To: Oleksandr Tymoshenko <gonzo@bluezbox.com> Cc: Tim Kientzle <tim@kientzle.com>, freebsd-arm@freebsd.org Subject: Re: Raspberry Pi No Login Message-ID: <CAJ-Vmon70OoAkEOqEOCwmDmPUrcOwDMq72nQHC1NHk7yd_wM6g@mail.gmail.com> In-Reply-To: <5116F226.7010204@bluezbox.com> References: <09931DEF-C90A-4E72-B5EE-02BB0C6A8588@kobudo.homeunix.net> <F9B0FF68-05F7-40FA-9150-CD0D602ADF9B@kientzle.com> <CALCpEUFNCojMLx2_90iKDyCoezdt3TgFYQ-EXafNhVCevN9OsQ@mail.gmail.com> <5109A3F2.7010508@bluezbox.com> <5116F226.7010204@bluezbox.com>
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Hey, nice catch! Adrian (hardware is fun!) On 9 February 2013 17:04, Oleksandr Tymoshenko <gonzo@bluezbox.com> wrote: > On 1/30/2013 2:51 PM, Oleksandr Tymoshenko wrote: >> >> On 1/30/2013 2:25 PM, hiren panchasara wrote: >>> >>> On Wed, Jan 30, 2013 at 9:15 AM, Tim Kientzle <tim@kientzle.com> wrote: >>>> >>>> On Jan 30, 2013, at 7:42 AM, Neal Nelson wrote: >>>> >>>>> HI. >>>>> >>>>> I'm able to build a bootable FreeBSD image using the beaglebone >>>>> scripts, which I understand is the accepted way at the moment. >>>>> >>>>> The problem I have is that everything seems to be going nicely, but I >>>>> never get a login prompt. The last thing I see, after the ssh key generation >>>>> stuff, is a line showing the date, then nothing. This is true using Current >>>>> as of today (2012-01-30). >>>>> >>>>> I've had this problem for some time now as every image I build using >>>>> this process has the same problem. If anyone has an idea as to what I'm >>>>> doing wrong, I'd be very grateful. >>>> >>>> Look at the kernel boot messages for the SD card >>>> check. >>>> >>>> Is it probing at 25MHz or 50MHz? >>>> >>>> I haven't tried RPi in a little while, but last time I did >>>> there was an erratic bug which caused the SD card >>>> to sometimes get probed at 50MHz and be non-functional. >>>> >>>> I believe some people worked around this by trying >>>> different cards or maybe it's been fixed in the >>>> SD driver by now? >>> >>> Not sure if its fixed in the driver now but I got around the frequency >>> problem by the patch available at: >>> http://www.peach.ne.jp/archives/rpi/patch/ >>> >>> Basically its setting freq to 25MHz instead of default 50MHz in >>> bcm2835_sdhci.c >> >> >> The patch works around the issue although it does address several issues >> with FreeBSD's >> generic mmc driver. Namely: driver does not check for return value for >> functions that read >> card's CSD, SCR or the result of switch command. CSD and SCR register >> contain card-specific >> information drivers uses to tune its operations. So when register read >> command silently >> fails driver uses partially valid data and hence its behavior might or >> might not manifest >> problems. >> >> Now the interesting part is why these commands fail. SDHCI controller >> returns Data CRC >> errors when executing them. It happens fairly early in initialization >> sequence so at that point >> card operates at 400KHz and should not have problem like this. > > > Today I went all scientific on this issue and plugged logic analyzer > to SD card using SparkFun's SD Sniffer[1]. What I found was that on > power up SDHCI controller starts operating at frequency of 190KHz but > shortly after it, before any data is read via DATA line, it switches to > 8MHz. So I capped minimum frequency for SDHCI driver at 8MHz and got > RPi into endless reboot cycle. Lo and behold: it's been almost two > hours and so far no Data CRC Error interrupts. > > Patch: http://people.freebsd.org/~gonzo/arm/patches/rpi-sdhci.diff > > Description: > - Do not silently ignore failure of "Read CSD" and "Read SCR" > commands since data returned by them is essential for further > initialization > - Properly calculate minimum frequency for SDHCI 3.00 and higher > - Add new method to SDHCI interface for setting driver-specific > minimum frequency. Provide default implementation. > - Cap minimum frequency at 8MHz for Raspberry Pi's SDHC > > I'd appreciate reviews and testing. There is one debug printf that > will be removed from final version. > > [1] https://www.sparkfun.com/products/11468 > > > _______________________________________________ > freebsd-arm@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-arm > To unsubscribe, send any mail to "freebsd-arm-unsubscribe@freebsd.org"
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