From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751403AbdAVGUU (ORCPT ); Sun, 22 Jan 2017 01:20:20 -0500 Received: from mga03.intel.com ([134.134.136.65]:62719 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751299AbdAVGUC (ORCPT ); Sun, 22 Jan 2017 01:20:02 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.33,267,1477983600"; d="scan'208";a="925274308" From: Lu Baolu To: Greg Kroah-Hartman , Ingo Molnar Cc: Mathias Nyman , tglx@linutronix.de, peterz@infradead.org, linux-usb@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, Lu Baolu Subject: [PATCH v6 2/4] x86: add support for earlyprintk via USB3 debug port Date: Sun, 22 Jan 2017 14:19:33 +0800 Message-Id: <1485065975-27504-3-git-send-email-baolu.lu@linux.intel.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1485065975-27504-1-git-send-email-baolu.lu@linux.intel.com> References: <1485065975-27504-1-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/admin-guide/kernel-parameters.txt | 1 + arch/x86/kernel/early_printk.c | 5 +++++ arch/x86/kernel/setup.c | 4 ++++ 3 files changed, 10 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index be7c0d9..4bf6138 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -988,6 +988,7 @@ 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..0f08403 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_USB_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 4cfba94..1f27d91 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -70,6 +70,7 @@ #include #include +#include #include