From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754295Ab0IMGtG (ORCPT ); Mon, 13 Sep 2010 02:49:06 -0400 Received: from mga03.intel.com ([143.182.124.21]:40484 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752713Ab0IMGtB (ORCPT ); Mon, 13 Sep 2010 02:49:01 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.56,358,1280732400"; d="scan'208";a="323825518" From: Feng Tang To: linux-kernel@vger.kernel.org Cc: mingo@elte.hu, alan@linux.intel.com, greg@kroah.com, Feng Tang , x86 maintainers Subject: [PATCH v3 4/4] x86, earlyprintk: add hsu early console for Intel Medfield platform Date: Mon, 13 Sep 2010 15:08:56 +0800 Message-Id: <1284361736-23011-5-git-send-email-feng.tang@intel.com> X-Mailer: git-send-email 1.7.0.4 In-Reply-To: <1284361736-23011-1-git-send-email-feng.tang@intel.com> References: <1284361736-23011-1-git-send-email-feng.tang@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Intel Medfield platform has a high speed UART device, which could act as a early console. To enable early printk of HSU console, simply add "earlyprintk=hsu" in kernel command line. Currently we put the code in the early_printk_mrst.c as it is also for Intel MID platforms like the mrst early console Signed-off-by: Feng Tang Cc: x86 maintainers Signed-off-by: Alan Cox --- arch/x86/include/asm/mrst.h | 3 + arch/x86/kernel/early_printk.c | 6 ++ arch/x86/kernel/early_printk_mrst.c | 89 ++++++++++++++++++++++++++++++++++- 3 files changed, 97 insertions(+), 1 deletions(-) diff --git a/arch/x86/include/asm/mrst.h b/arch/x86/include/asm/mrst.h index d0ea5bc..4a711a6 100644 --- a/arch/x86/include/asm/mrst.h +++ b/arch/x86/include/asm/mrst.h @@ -47,4 +47,7 @@ extern enum mrst_timer_options mrst_timer_options; extern struct console early_mrst_console; extern void mrst_early_console_init(void); + +extern struct console early_hsu_console; +extern void hsu_early_console_init(void); #endif /* _ASM_X86_MRST_H */ diff --git a/arch/x86/kernel/early_printk.c b/arch/x86/kernel/early_printk.c index 6082463..4572f25 100644 --- a/arch/x86/kernel/early_printk.c +++ b/arch/x86/kernel/early_printk.c @@ -245,6 +245,12 @@ static int __init setup_early_printk(char *buf) mrst_early_console_init(); early_console_register(&early_mrst_console, keep); } + + if (!strncmp(buf, "hsu", 3)) { + hsu_early_console_init(); + early_console_register(&early_hsu_console, keep); + } + #endif buf++; } diff --git a/arch/x86/kernel/early_printk_mrst.c b/arch/x86/kernel/early_printk_mrst.c index 05d27e1..65df603 100644 --- a/arch/x86/kernel/early_printk_mrst.c +++ b/arch/x86/kernel/early_printk_mrst.c @@ -1,5 +1,5 @@ /* - * early_printk_mrst.c - spi-uart early printk for Intel Moorestown platform + * early_printk_mrst.c - early consoles for Intel MID platforms * * Copyright (c) 2008-2010, Intel Corporation * @@ -9,9 +9,19 @@ * of the License. */ +/* + * This file implements two early consoles named mrst and hsu. + * mrst is based on Maxim3110 spi-uart device, it exists in both + * Moorestown and Medfield platforms, while hsu is based on a High + * Speed UART device which only exists in the Medfield platform + */ + +#include +#include #include #include #include +#include #include #include @@ -230,3 +240,80 @@ struct console early_mrst_console = { .flags = CON_PRINTBUFFER, .index = -1, }; + +/* + * Following is the early console based on Medfield HSU (High + * Speed UART) device. + */ +#define HSU_PORT2_PADDR 0xffa28180 + +static void __iomem *phsu; + +void hsu_early_console_init(void) +{ + u8 lcr; + + phsu = (void *)set_fixmap_offset_nocache(FIX_EARLYCON_MEM_BASE, + HSU_PORT2_PADDR); + + /* Disable FIFO */ + writeb(0x0, phsu + UART_FCR); + + /* Set to default 115200 bps, 8n1 */ + lcr = readb(phsu + UART_LCR); + writeb((0x80 | lcr), phsu + UART_LCR); + writeb(0x18, phsu + UART_DLL); + writeb(lcr, phsu + UART_LCR); + writel(0x3600, phsu + UART_MUL*4); + + writeb(0x8, phsu + UART_MCR); + writeb(0x7, phsu + UART_FCR); + writeb(0x3, phsu + UART_LCR); + + /* Clear IRQ status */ + readb(phsu + UART_LSR); + readb(phsu + UART_RX); + readb(phsu + UART_IIR); + readb(phsu + UART_MSR); + + /* Enable FIFO */ + writeb(0x7, phsu + UART_FCR); +} + +#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE) + +static void early_hsu_putc(char ch) +{ + unsigned int timeout = 10000; /* 10ms */ + u8 status; + + while (--timeout) { + status = readb(phsu + UART_LSR); + if (status & BOTH_EMPTY) + break; + udelay(1); + } + + /* Only write the char when there was no timeout */ + if (timeout) + writeb(ch, phsu + UART_TX); +} + +static void early_hsu_write(struct console *con, const char *str, unsigned n) +{ + int i; + + for (i = 0; i < n && *str; i++) { + if (*str == '\n') + early_hsu_putc('\r'); + early_hsu_putc(*str); + str++; + } +} + +struct console early_hsu_console = { + .name = "earlyhsu", + .write = early_hsu_write, + .flags = CON_PRINTBUFFER, + .index = -1, +}; -- 1.7.0.4