From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Fri, 05 Feb 2010 15:31:54 +0100 (CET) Received: from mail-bw0-f226.google.com ([209.85.218.226]:65145 "EHLO mail-bw0-f226.google.com" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S1492671Ab0BEObu (ORCPT ); Fri, 5 Feb 2010 15:31:50 +0100 Received: by bwz26 with SMTP id 26so2930219bwz.27 for ; Fri, 05 Feb 2010 06:31:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:sender:date:from:to:cc :subject:message-id:x-mailer:mime-version:content-type :content-transfer-encoding; bh=MTLGAMuDiiCeZcUH3iOiJOiWEydDfWUmjVK4EuKv60Y=; b=LzzuIqSfVNXTU96aMd/QMq9ttaDxx2tCLIo8/wbGCrDrj3jEPHi0DRHwucZyeCcnIw QgDwF1ZZNDcCyX4Jiu07QNfN7rbNvfEEOdby27jubPHT+NwSdeAI3HROHVneEIsUVFw7 EGZ7gEXS3irOjo7d2tBiLHtMINZ99zDQnbVzg= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=sender:date:from:to:cc:subject:message-id:x-mailer:mime-version :content-type:content-transfer-encoding; b=ihFkemBDStS6n6fvcI8yEnfh/F1MtTDJAxIN6cfaie123x8CCbwWO2awXFLvX7W4WF GJUyzvEjs4F0vh2xpwKw9gyCTwx6vFxRGveb1OIsujMXrGQdn967e3fjzijL3XlrtnQW CCEzZzi7YCci9bS8fJxfEDD9A/4HbkqH1CnPg= Received: by 10.204.156.204 with SMTP id y12mr1807566bkw.3.1265380304539; Fri, 05 Feb 2010 06:31:44 -0800 (PST) Received: from ypsilon.skybright.jp (sannin29006.nirai.ne.jp [203.160.29.6]) by mx.google.com with ESMTPS id 16sm641571bwz.7.2010.02.05.06.31.40 (version=TLSv1/SSLv3 cipher=RC4-MD5); Fri, 05 Feb 2010 06:31:42 -0800 (PST) Date: Fri, 5 Feb 2010 23:28:57 +0900 From: Yoichi Yuasa To: Ralf Baechle Cc: yuasa@linux-mips.org, linux-mips Subject: [PATCH 1/2] MIPS: add 8250/16550 serial early printk driver Message-Id: <20100205232857.eb65967f.yuasa@linux-mips.org> X-Mailer: Sylpheed 2.7.1 (GTK+ 2.16.6; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 25878 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: yuasa@linux-mips.org Precedence: bulk X-list: linux-mips Signed-off-by: Yoichi Yuasa --- arch/mips/Kconfig.debug | 8 ++++ arch/mips/include/asm/setup.h | 9 ++++ arch/mips/kernel/Makefile | 1 + arch/mips/kernel/early_printk_8250.c | 68 ++++++++++++++++++++++++++++++++++ 4 files changed, 86 insertions(+), 0 deletions(-) create mode 100644 arch/mips/kernel/early_printk_8250.c diff --git a/arch/mips/Kconfig.debug b/arch/mips/Kconfig.debug index 32a010d..f5d739c 100644 --- a/arch/mips/Kconfig.debug +++ b/arch/mips/Kconfig.debug @@ -20,6 +20,14 @@ config EARLY_PRINTK doesn't cooperate with an X server. You should normally say N here, unless you want to debug such a crash. +config EARLY_PRINTK_8250 + bool "8250/16550 and compatible serial early printk driver" + depends on EARLY_PRINTK + default n + help + If you say Y here, it will be possible to use a 8250/16550 serial + port as the boot console. + config CMDLINE_BOOL bool "Built-in kernel command line" default n diff --git a/arch/mips/include/asm/setup.h b/arch/mips/include/asm/setup.h index 50511aa..7395b7f 100644 --- a/arch/mips/include/asm/setup.h +++ b/arch/mips/include/asm/setup.h @@ -5,6 +5,15 @@ #ifdef __KERNEL__ extern void setup_early_printk(void); + +#ifdef CONFIG_EARLY_PRINTK_8250 +extern void setup_8250_early_printk_port(unsigned long base, + unsigned int reg_shift, unsigned int timeout); +#else +static inline void setup_8250_early_printk_port(unsigned long base, + unsigned int reg_shift, unsigned int timeout) {} +#endif + #endif /* __KERNEL__ */ #endif /* __SETUP_H */ diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile index 9326af5..03fc037 100644 --- a/arch/mips/kernel/Makefile +++ b/arch/mips/kernel/Makefile @@ -93,6 +93,7 @@ obj-$(CONFIG_GPIO_TXX9) += gpio_txx9.o obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o obj-$(CONFIG_EARLY_PRINTK) += early_printk.o +obj-$(CONFIG_EARLY_PRINTK_8250) += early_printk_8250.o CFLAGS_cpu-bugs64.o = $(shell if $(CC) $(KBUILD_CFLAGS) -Wa,-mdaddi -c -o /dev/null -xc /dev/null >/dev/null 2>&1; then echo "-DHAVE_AS_SET_DADDI"; fi) diff --git a/arch/mips/kernel/early_printk_8250.c b/arch/mips/kernel/early_printk_8250.c new file mode 100644 index 0000000..6faf8fd --- /dev/null +++ b/arch/mips/kernel/early_printk_8250.c @@ -0,0 +1,68 @@ +/* + * 8250/16550-type serial ports prom_putchar() + * + * Copyright (C) 2010 Yoichi Yuasa + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ +#include +#include +#include + +static unsigned long serial8250_base; +static unsigned int serial8250_reg_shift; +static unsigned int serial8250_tx_timeout; + +void setup_8250_early_printk_port(unsigned long base, unsigned int reg_shift, + unsigned int timeout) +{ + serial8250_base = base; + serial8250_reg_shift = reg_shift; + serial8250_tx_timeout = timeout; +} + +static inline u8 serial_in(int offset) +{ + return readb((void __iomem *)serial8250_base + + (offset << serial8250_reg_shift)); +} + +static inline void serial_out(int offset, char value) +{ + writeb(value, (void __iomem *)serial8250_base + + (offset << serial8250_reg_shift)); +} + +void prom_putchar(char c) +{ + unsigned int timeout; + int status, bits; + + if (!serial8250_base) + return; + + timeout = serial8250_tx_timeout; + bits = UART_LSR_TEMT | UART_LSR_THRE; + + do { + status = serial_in(UART_LSR); + + if (--timeout == 0) + break; + } while ((status & bits) != bits); + + if (timeout) + serial_out(UART_TX, c); +} -- 1.6.6.1