Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756848AbdCUIDv (ORCPT ); Tue, 21 Mar 2017 04:03:51 -0400 Received: from mga04.intel.com ([192.55.52.120]:31012 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756260AbdCUICN (ORCPT ); Tue, 21 Mar 2017 04:02:13 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.36,198,1486454400"; d="scan'208";a="946522506" 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 v8 3/5] x86: add support for earlyprintk via USB3 debug port Date: Tue, 21 Mar 2017 16:01:31 +0800 Message-Id: <1490083293-3792-4-git-send-email-baolu.lu@linux.intel.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1490083293-3792-1-git-send-email-baolu.lu@linux.intel.com> References: <1490083293-3792-1-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 Content-Length: 2561 Lines: 77 Add support for earlyprintk by writing debug messages to the USB3 debug port. Users can use this type of early printk by specifying the kernel parameter of "earlyprintk=xdbc". This gives users a chance of providing debugging 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 2ba45ca..ea1293d 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -989,6 +989,7 @@ 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 e70204e..2600b1d 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -70,6 +70,7 @@ #include #include +#include #include