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    SubjectRe: [PATCH 1/2] MIPS: Add basic support for Loongson1B (UPDATED)
    From
    >> diff --git a/arch/mips/include/asm/mach-loongson1/regs-clk.h b/arch/mips/include/asm/mach-loongson1/regs-clk.h
    >> new file mode 100644
    >> index 0000000..7a09d6a
    >> --- /dev/null
    >> +++ b/arch/mips/include/asm/mach-loongson1/regs-clk.h
    >> @@ -0,0 +1,32 @@
    >> +/*
    >> + * Copyright (c) 2011 Zhang, Keguang <keguang.zhang@gmail.com>
    >> + *
    >> + * Loongson1 Clock Register Definitions.
    >> + *
    >> + * 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.
    >> + */
    >> +
    >> +#ifndef __ASM_MACH_LOONGSON1_REGS_CLK_H
    >> +#define __ASM_MACH_LOONGSON1_REGS_CLK_H
    >> +
    >> +#define LS1_CLK_REG(x)         ((void __iomem *)(LOONGSON1_CLK_BASE + (x)))
    >
    > "volatile" keyword may be required for __iomem access, the same to the
    > following similar usage.
    >
    > Considering a scene is(LS1_XXX_REG(X) doesn't really exist):
    >
    > LS1_XXX_REG(X) = 0;              /* put cpu into idle and wait interrupt */
    > LS1_XXX_REG(X) = 7;              /* recover the cpu frequency to the highest */
    >
    > If no "volatile" keyword indicated, the above two lines will be
    > intelligently but wrongly removed by compiler.

    No -- please see Documentation/volatile-considered-harmful.txt,
    particularly the paragraph starting at line 49. This macro
    is only being used as an argument to __raw_readl,
    as it should be.

    Shane
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