From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from yw-out-2324.google.com (yw-out-2324.google.com [74.125.46.31]) by ozlabs.org (Postfix) with ESMTP id 9DC63DDE41 for ; Tue, 18 Nov 2008 11:56:42 +1100 (EST) Received: by yw-out-2324.google.com with SMTP id 5so1081308ywh.39 for ; Mon, 17 Nov 2008 16:56:41 -0800 (PST) Message-ID: Date: Mon, 17 Nov 2008 18:56:41 -0600 From: "Timur Tabi" Sender: timur.tabi@gmail.com To: linuxppc-dev@ozlabs.org Subject: Some udbg questions MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , I'm adding udbg support to my console driver, and I've noticed that there is not much consistency on how the various platforms implement udbg support. So I have a few questions: 1. What is the point of implementing udbg_getc? What does the console do with any characters it receives this early? 2. In my driver's udbg initialization function, should I be able to parse the device tree to get parameters? 3. What about command-line parameters? 4. The LPAR and PMAC platforms call register_early_udbg_console (in the udbg_init_debug_lpar and pmac_init_early functions, respectively), but none of the other platforms do. It appears that the other platforms rely on setup_32.c and setup_64.c to call this function. What's so special about LPAR and PMAC? 5. Some platforms (like mv64x60) use the ppc_md.init_early function to initialize the early console. Others update function udbg_early_init() in udbg.c instead. Why do some platforms do it one way, and other platforms do it the other way? Which way is preferred? -- Timur Tabi Linux kernel developer at Freescale