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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: Gabor Juhos <juhosg@openwrt.org>
Date: Thu, 24 Jan 2013 13:11:45 +0100
Cc: Ralf Baechle <ralf@linux-mips.org>, linux-mips@linux-mips.org
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2013.01.23. 13:05 keltezéssel, John Crispin írta:
> 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
> +
> +static inline void uart_w32(u32 val, unsigned reg)
> +{
> +     __raw_writel((val),
> +             (void __iomem *)(KSEG1ADDR(EARLY_UART_BASE) + 4 * (reg)));

Introducing a variable for the base address would make the code much more
readable. Additionaly, compared to the OpenWrt code this is not a macro anymore,
so the parentheses around 'val' and 'reg' are not needed.

> +}
> +
> +static inline u32 uart_r32(unsigned reg)
> +{
> +     return __raw_readl(
> +             (void __iomem *)(KSEG1ADDR(EARLY_UART_BASE) + 4 * (reg)));

Ditto.

> +}
> +
> +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);

There are some superfluous parentheses inside the conditions of the while
statements. Apart from that, the trailing semicolons will cause checkpatch 
errors.

-Gabor

-Gabor

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