Date: Mon, 7 Apr 2014 18:41:16 -0700 From: Tim Kientzle <kientzle@freebsd.org> To: Xuebing Wang <xbing6@gmail.com> Cc: freebsd-arm@freebsd.org Subject: Re: [BeagleBone Black Test PATCH 0/2] port latest u-boot Message-ID: <C38629E3-59AC-4100-8748-01FF3F4FBC69@freebsd.org> In-Reply-To: <1396862732-4961-1-git-send-email-xbing6@gmail.com>
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On Apr 7, 2014, at 2:25 AM, Xuebing Wang <xbing6@gmail.com> wrote: > Hi Tim and all, > > This is for discussion only. Would you please advice? > > This is motivated by trying to increase CPU frequency for BeagleBone Black. > > AM335x cpufreq is not supported yet. In order to achieve the goal to increase > CPU freq, I am thinking of a 2-step approach: > 1) port latest u-boot, which have cpufreq better organized > 2) tweak u-boot opp/freq later Setting the processor frequency after the OS is running is not difficult. The AM335x TRM shows exactly how to do it. I would not change U-Boot but rather implement a FreeBSD driver that exposed a read/write sysctl to reprogram the CPU frequency. Getting powerd to work with this should be straightforward. Timhelp
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