From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from wr-out-0506.google.com (wr-out-0506.google.com [64.233.184.237]) by ozlabs.org (Postfix) with ESMTP id CF4AADDDFD for ; Thu, 22 Nov 2007 11:20:48 +1100 (EST) Received: by wr-out-0506.google.com with SMTP id 68so1007462wri for ; Wed, 21 Nov 2007 16:20:47 -0800 (PST) Message-ID: Date: Wed, 21 Nov 2007 17:20:46 -0700 From: "Grant Likely" Sender: glikely@secretlab.ca To: benh@kernel.crashing.org Subject: Re: [PATCH 12/14] powerpc: Add early udbg support for 40x processors In-Reply-To: <1195689601.6970.115.camel@pasglop> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 References: <20071121061555.55B06DDFA8@ozlabs.org> <1195689601.6970.115.camel@pasglop> Cc: linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 11/21/07, Benjamin Herrenschmidt wrote: > > On Wed, 2007-11-21 at 16:47 -0700, Grant Likely wrote: > > On 11/20/07, Benjamin Herrenschmidt wrote: > > > This adds some basic real mode based early udbg support for 40x > > > in order to debug things more easily > > > > > > Signed-off-by: Benjamin Herrenschmidt > > > --- > > > --- linux-work.orig/arch/powerpc/platforms/Kconfig.cputype 2007-11-21 12:50:16.000000000 +1100 > > > +++ linux-work/arch/powerpc/platforms/Kconfig.cputype 2007-11-21 12:50:18.000000000 +1100 > > > @@ -43,6 +43,7 @@ config 40x > > > bool "AMCC 40x" > > > select PPC_DCR_NATIVE > > > select WANT_DEVICE_TREE > > > + select PPC_UDBG_16550 > > > > Unfortunately, this isn't always true. The Xilinx Virtex parts us > > config 40x, but not all FPGA bitstreams have a 16550 serial port. > > Sometimes it's a uartlite instead. > > What does uartlite looks like ? fixed speed 4 registers: rx, tx, status & control rx & tx are... well... rx and tx registers status has a number of bits reporting fifos full/empty etc. control has three bits; reset tx, reset rx and interrupt enable. See the top of drivers/serial/uartlite.c Very simple stuff; but definitely not 16550. g. -- Grant Likely, B.Sc., P.Eng. Secret Lab Technologies Ltd. grant.likely@secretlab.ca (403) 399-0195