From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Tomoya MORINAGA <tomoya.rohm@gmail.com>
Cc: Darren Hart <dvhart@linux.intel.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Feng Tang <feng.tang@intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Alan Cox <alan@linux.intel.com>,
linux-serial@vger.kernel.org
Subject: Re: [PATCH 0/4] pch_uart: Cleanups, board quirks, and user uartclk parameter
Date: Wed, 22 Feb 2012 08:58:30 +0000 [thread overview]
Message-ID: <20120222085830.1ed8c25e@pyramind.ukuu.org.uk> (raw)
In-Reply-To: <CANKRQni9E6NO39MFSak6MjQ0DtmQeviGo966Ex9ZUvai56wCjg@mail.gmail.com>
> > assume a 192 MHz clock on all boards. The problem with this approach is
> > that the CLKCFG register may have been set to something other than the
> > 192MHz configuration by the firmware.
So you can use the early PCI hooks or even bash the register directly in
your early bootup code. You won't be the only early boot console that
does this sort of thing. There are even people bitbanging PCI I²C
interfaces at boot time for such purpose.
> So, I think default uart_clock 192MHz setting is better than Darren's opinion.
It's certainly easier to maintain, but it would be good to know if the
setting can be written or retrieved directly in the early console setup
using the early PCI ops or similar.
Alan
Alan
next prev parent reply other threads:[~2012-02-22 8:58 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-22 1:59 [PATCH 0/4] pch_uart: Cleanups, board quirks, and user uartclk parameter Darren Hart
2012-02-22 1:59 ` [PATCH 1/4] pch_uart: Use uartclk instead of base_baud Darren Hart
2012-02-22 1:59 ` [PATCH 2/4] pch_uart: Add Fish River Island II uart clock quirks Darren Hart
2012-02-22 8:52 ` Alan Cox
2012-02-22 9:46 ` Darren Hart
2012-02-24 21:53 ` Greg Kroah-Hartman
2012-02-24 22:25 ` Darren Hart
2012-02-24 23:39 ` Greg Kroah-Hartman
2012-02-22 1:59 ` [PATCH 3/4] pch_uart: Add user_uartclk parameter Darren Hart
2012-02-22 1:59 ` [PATCH 4/4] pch_uart: Use existing default_baud in setup_console Darren Hart
2012-02-22 3:10 ` [PATCH 0/4] pch_uart: Cleanups, board quirks, and user uartclk parameter Tomoya MORINAGA
2012-02-22 3:36 ` Darren Hart
2012-02-22 4:26 ` Tomoya MORINAGA
2012-02-22 6:39 ` Darren Hart
2012-02-22 8:16 ` Tomoya MORINAGA
2012-02-22 8:59 ` Darren Hart
2012-02-22 9:25 ` Feng Tang
2012-02-22 8:58 ` Alan Cox [this message]
2012-02-22 9:55 ` Darren Hart
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