From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from canuck.infradead.org (canuck.infradead.org [209.217.80.40]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id 30243DE15B for ; Sun, 8 Jul 2007 00:59:15 +1000 (EST) Subject: Re: [PATCH] Handle reg-shift property for of_serial ports From: David Woodhouse To: Arnd Bergmann , wmb@firmworks.com In-Reply-To: <200707071410.14998.arnd@arndb.de> References: <1183784308.3066.16.camel@shinybook.infradead.org> <200707071410.14998.arnd@arndb.de> Content-Type: text/plain Date: Sat, 07 Jul 2007 10:59:39 -0400 Message-Id: <1183820379.3066.40.camel@shinybook.infradead.org> Mime-Version: 1.0 Cc: linuxppc-dev@ozlabs.org, paulus@samba.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Sat, 2007-07-07 at 14:10 +0200, Arnd Bergmann wrote: > On Saturday 07 July 2007, David Woodhouse wrote: > > > > The MV64660 has reg-shift==2 for its otherwise 16550-compatible uarts. > > While the bootwrapper copes with this, of_serial.c doesn't. (The udbg > > code doesn't either, but I'll fix that later). > > > > Signed-off-by: David Woodhouse > > Acked-by: Arnd Bergmann > > Given the existence of the boards, it looks correct to do this. > However, I wonder if it was correct for the MV64660 to claim > compatibily witn ns16550 if the programming model is not exactly > the same. The official OF serial port bindings don't mention the > reg-shift property, so it maybe would have been better to have > a different value for the "compatible" property, in order not > to confuse existing operating systems that implement the standard. Well, so far this only exists in the hacked-up device tree for my bootwrapper; not in any real firmware. If a reg-shift property is the wrong way to do it, we can change it. I got the reg-shift thing from Mark's code in arch/powerpc/boot/ns16550.c, which handles it that way for the bootwrapper (although I don't see any device-tree blobs which use it, apart from mine). -- dwmw2