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As pointed out in the following thread, the CLOCK_TICK_RATE setting for IXP4xx is incorrect b/c the HW ignores the lowest 2 bits of the LATCH value. http://lists.arm.linux.org.uk/pipermail/linux-arm-kernel/2005-August/030950.html Tnx to George Anziger and Egil Hjelmeland for finding the issue. Signed-off-by: Deepak Saxena <dsaxena@plexity.net> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
16 lines
399 B
C
16 lines
399 B
C
/*
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* linux/include/asm-arm/arch-ixp4xx/timex.h
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*
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*/
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#include <asm/hardware.h>
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/*
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* We use IXP425 General purpose timer for our timer needs, it runs at
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* 66.66... MHz. We do a convulted calculation of CLOCK_TICK_RATE b/c the
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* timer register ignores the bottom 2 bits of the LATCH value.
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*/
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#define FREQ 66666666
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#define CLOCK_TICK_RATE (((FREQ / HZ & ~IXP4XX_OST_RELOAD_MASK) + 1) * HZ)
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