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/*
* include/asm-arm/arch-ns9xxx/clock.h
*
* Copyright (C) 2007 by Digi International Inc.
* All rights reserved.
*
* 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.
*/
#ifndef __ASM_ARCH_CLOCK_H
#define __ASM_ARCH_CLOCK_H
#include <asm/arch-ns9xxx/regs-sys.h>
#define CRYSTAL 29491200 /* Hz */
/* The HRM calls this value f_vco */
static inline u32 ns9xxx_systemclock(void) __attribute__((const));
static inline u32 ns9xxx_systemclock(void)
{
u32 pll = __raw_readl(SYS_PLL);
/*
* The system clock should be a multiple of HZ * TIMERCLOCKSELECT (in
* time.c).
*
* The following values are given:
* - TIMERCLOCKSELECT == 2^i for an i in {0 .. 6}
* - CRYSTAL == 29491200 == 2^17 * 3^2 * 5^2
* - ND in {0 .. 31}
* - FS in {0 .. 3}
*
* Assuming the worst, we consider:
* - TIMERCLOCKSELECT == 64
* - ND == 0
* - FS == 3
*
* So HZ should be a divisor of:
* (CRYSTAL * (ND + 1) >> FS) / TIMERCLOCKSELECT
* == (2^17 * 3^2 * 5^2 * 1 >> 3) / 64
* == 2^8 * 3^2 * 5^2
* == 57600
*
* Currently HZ is defined to be 100 for this platform.
*
* Fine.
*/
return CRYSTAL * (REGGETIM(pll, SYS_PLL, ND) + 1)
>> REGGETIM(pll, SYS_PLL, FS);
}
static inline u32 ns9xxx_cpuclock(void) __attribute__((const));
static inline u32 ns9xxx_cpuclock(void)
{
return ns9xxx_systemclock() / 2;
}
static inline u32 ns9xxx_ahbclock(void) __attribute__((const));
static inline u32 ns9xxx_ahbclock(void)
{
return ns9xxx_systemclock() / 4;
}
static inline u32 ns9xxx_bbusclock(void) __attribute__((const));
static inline u32 ns9xxx_bbusclock(void)
{
return ns9xxx_systemclock() / 8;
}
#endif /* ifndef __ASM_ARCH_CLOCK_H */
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