linux-mips
[Top] [All Lists]

Re: [RFC 08/11] MIPS: ralink: adds early_printk support

To: John Crispin <blogic@openwrt.org>
Subject: Re: [RFC 08/11] MIPS: ralink: adds early_printk support
From: Florian Fainelli <florian@openwrt.org>
Date: Wed, 23 Jan 2013 20:23:20 +0100
Cc: Ralf Baechle <ralf@linux-mips.org>, linux-mips@linux-mips.org
Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=x-received:sender:message-id:date:from:organization:user-agent :mime-version:to:cc:subject:references:in-reply-to:content-type :content-transfer-encoding; bh=KwK1dDsTRPwm/KCnDfPB4NAt8hYkX+GWdqzwh+uD3FM=; b=udBM7oYLArnyBOH39UcTIPsCK1KcZ7hSkSLmdMk/aGmWm62IyjD7Mzj03ATgTnBGEV DpJS9sMTHasf+5+POiBMnP/Ga7QD8BSf1Mis8SM6IUQDsDa+KD2AF/O1bNSkEdGTaGw9 c7BeZtIYJIXV8VpsdA/rVwS0enLwxjVpwlbwzX9YoCvC9XKVBpe3dR29y/a7WglVC7FU dDG4bATgjH0EUWCYrwK0ZE3nAMGWPF5EbwFzKA7yKKs6FhTYRsYPrlIF1Gym8m6jmH+k FdrvkAZscdsKHj/5j3RS3QVbXBPX+Lfn3l1Fh1tQBASXQFRh5cwn8aMjHHw8Ftq8aLPR se+g==
In-reply-to: <1358942755-25371-9-git-send-email-blogic@openwrt.org>
List-archive: <http://www.linux-mips.org/archives/linux-mips/>
List-help: <mailto:ecartis@linux-mips.org?Subject=help>
List-id: linux-mips <linux-mips.eddie.linux-mips.org>
List-owner: <mailto:ralf@linux-mips.org>
List-post: <mailto:linux-mips@linux-mips.org>
List-software: Ecartis version 1.0.0
List-subscribe: <mailto:ecartis@linux-mips.org?subject=subscribe%20linux-mips>
List-unsubscribe: <mailto:ecartis@linux-mips.org?subject=unsubscribe%20linux-mips>
Organization: OpenWrt
References: <1358942755-25371-1-git-send-email-blogic@openwrt.org> <1358942755-25371-9-git-send-email-blogic@openwrt.org>
Sender: linux-mips-bounce@linux-mips.org
User-agent: Mozilla/5.0 (Windows NT 5.1; rv:17.0) Gecko/20130107 Thunderbird/17.0.2
Hey John,

Le 23/01/2013 13:05, John Crispin a écrit :
Add the code needed to make early printk work.

Signed-off-by: John Crispin <blogic@openwrt.org>
---
  arch/mips/ralink/early_printk.c |   43 +++++++++++++++++++++++++++++++++++++++
  1 file changed, 43 insertions(+)
  create mode 100644 arch/mips/ralink/early_printk.c

diff --git a/arch/mips/ralink/early_printk.c b/arch/mips/ralink/early_printk.c
new file mode 100644
index 0000000..c610084
--- /dev/null
+++ b/arch/mips/ralink/early_printk.c
@@ -0,0 +1,43 @@
+/*
+ *  This program is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License version 2 as published
+ *  by the Free Software Foundation.
+ *
+ *  Copyright (C) 2011-2012 Gabor Juhos <juhosg@openwrt.org>
+ */
+
+#include <linux/io.h>
+#include <linux/serial_reg.h>
+
+#include <asm/addrspace.h>
+
+/* UART registers */
+#define EARLY_UART_BASE         0x10000c00
+
+#define UART_REG_RX             0
+#define UART_REG_TX             1
+#define UART_REG_IER            2
+#define UART_REG_IIR            3
+#define UART_REG_FCR            4
+#define UART_REG_LCR            5
+#define UART_REG_MCR            6
+#define UART_REG_LSR            7

Is that really required considering that you already include serial_reg.h and could use defines from there?

At some point I think that we might be able to come up with a some kind of generic 8250 earlyprintk code where people just tell what's the base address of their UART. Something like:

#define UART_BASE       KSEG1ADDR(MY_UART_BASE)
#include <asm/8250-earlyprintk.h>

+
+static inline void uart_w32(u32 val, unsigned reg)
+{
+       __raw_writel((val),
+               (void __iomem *)(KSEG1ADDR(EARLY_UART_BASE) + 4 * (reg)));
+}
+
+static inline u32 uart_r32(unsigned reg)
+{
+       return __raw_readl(
+               (void __iomem *)(KSEG1ADDR(EARLY_UART_BASE) + 4 * (reg)));
+}
+
+void prom_putchar(unsigned char ch)
+{
+       while (((uart_r32(UART_REG_LSR)) & UART_LSR_THRE) == 0);
+       uart_w32(UART_REG_TX, ch);
+       while (((uart_r32(UART_REG_LSR)) & UART_LSR_THRE) == 0);
+}



<Prev in Thread] Current Thread [Next in Thread>