Date: Mon, 7 Oct 2013 13:15:16 -0700 From: Adrian Chadd <adrian@freebsd.org> To: Zbigniew Bodek <zbb@freebsd.org> Cc: "freebsd-arm@freebsd.org" <freebsd-arm@freebsd.org>, freebsd-current <freebsd-current@freebsd.org>, "freebsd-embedded@freebsd.org" <freebsd-embedded@freebsd.org> Subject: Re: Changes to UART ns8250 Message-ID: <CAJ-VmokZHvLpUvvD9s8ES0PT%2BE1oVfHWhdbiXF77osBOK2_Yqg@mail.gmail.com> In-Reply-To: <CALF_Tx=AwVnr0d75-K-yu97iVgmTJC7aaABoix73zHD%2B5eKJnQ@mail.gmail.com> References: <CALF_Tx=AwVnr0d75-K-yu97iVgmTJC7aaABoix73zHD%2B5eKJnQ@mail.gmail.com>
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Hi, You should add: * a loop counter, to break out after a while; * a DELAY(1) or something. -adrian On 7 October 2013 12:54, Zbigniew Bodek <zbb@freebsd.org> wrote: > Hello. > > I would like to present a patch for ns8250 serial that I would like to > commit in the near future (if there are no objections). > > The patch is fixing newest DesignWare UART with busy detection. > During frequency divisors configuration when UART is busy transferring or > receiving data, line control register manipulation will not take effect. > Therefore, we will not set divisor latch access bit and we will corrupt LCR > instead of configuring divisors. > It is necessary to wait until UART finishes all transfers to proceed with > the configuration. > > This was detected on Armada XP as UART fails on this issue 100/100 > attempts. > The patch was tested by kevlo@ and me and it works on our Armada XP - > based > systems. > > Please send your comment or remarks if there are any. > > Best regards > Zbigniew Bodek > > _______________________________________________ > freebsd-current@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-current > To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org" >
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