From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1163042AbcKAE7y (ORCPT ); Tue, 1 Nov 2016 00:59:54 -0400 Received: from mga07.intel.com ([134.134.136.100]:30696 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1162990AbcKAE7u (ORCPT ); Tue, 1 Nov 2016 00:59:50 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.31,430,1473145200"; d="scan'208";a="26337625" From: Lu Baolu To: Greg Kroah-Hartman Cc: Mathias Nyman , Ingo Molnar , linux-usb@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, Lu Baolu Subject: [PATCH v4 2/4] x86: add support for earlyprintk via USB3 debug port Date: Tue, 1 Nov 2016 12:59:12 +0800 Message-Id: <1477976354-13291-3-git-send-email-baolu.lu@linux.intel.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1477976354-13291-1-git-send-email-baolu.lu@linux.intel.com> References: <1477976354-13291-1-git-send-email-baolu.lu@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add support for early printk by writing debug messages to the USB3 debug port. Users can use this type of early printk by specifying kernel parameter of "earlyprintk=xdbc". This gives users a chance of providing debug output. The hardware for USB3 debug port requires DMA memory blocks. This requires to delay setting up debugging hardware and registering boot console until the memblocks are filled. Cc: Ingo Molnar Cc: x86@kernel.org Signed-off-by: Lu Baolu --- Documentation/kernel-parameters.txt | 1 + arch/x86/kernel/early_printk.c | 5 +++++ arch/x86/kernel/setup.c | 7 +++++++ 3 files changed, 13 insertions(+) diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 37babf9..99b64b3 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1178,6 +1178,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted. earlyprintk=ttySn[,baudrate] earlyprintk=dbgp[debugController#] earlyprintk=pciserial,bus:device.function[,baudrate] + earlyprintk=xdbc[xhciController#] earlyprintk is useful when the kernel crashes before the normal console is initialized. It is not enabled by diff --git a/arch/x86/kernel/early_printk.c b/arch/x86/kernel/early_printk.c index 8a12199..c4031b9 100644 --- a/arch/x86/kernel/early_printk.c +++ b/arch/x86/kernel/early_printk.c @@ -17,6 +17,7 @@ #include #include #include +#include #include #include #include @@ -381,6 +382,10 @@ static int __init setup_early_printk(char *buf) if (!strncmp(buf, "efi", 3)) early_console_register(&early_efi_console, keep); #endif +#ifdef CONFIG_EARLY_PRINTK_XDBC + if (!strncmp(buf, "xdbc", 4)) + early_xdbc_parse_parameter(buf + 4); +#endif buf++; } diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index 9c337b0..09d4a56 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -70,6 +70,8 @@ #include #include +#include + #include