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/*
* arch/sh/kernel/trace-clock.c
*
* Trace clock for SuperH.
*
* Copyright (C) 2010 STMicroelectronics Ltd
*
* Author: Giuseppe Cavallaro <peppe.cavallaro@st.com>
*
* Note: currently only tested and supported on SH4 CPU
* (TODO: tests on other SuperH architectures).
*/
#include <linux/module.h>
#include <linux/clocksource.h>
#include <asm/clock.h>
static struct clocksource *clksrc;
/* In case of the TMU, for SH4 architectures, it returns
* the value of timer counter register (TCNT). */
u32 sh_read_timer_count(void)
{
u32 value = 0;
if (likely(clksrc))
value = (u32) clksrc->read(clksrc);
return value;
}
/* Get the clock rate for the timer (e.g. TMU for SH4) */
u64 sh_get_clock_frequency(void)
{
u64 rate = 0;
struct clk *clk;
clk = clk_get(NULL, "module_clk");
if (likely(clk))
rate = clk_get_rate(clk) / 4;
return rate;
}
/* Get the clock source needed to read the timer counter.
* For example a TMU channel for SH4 architectures. */
static __init int init_sh_clocksource(void)
{
clksrc = clocksource_get_next();
if (unlikely(!clksrc))
pr_err("%s: no clocksource found\n", __func__);
return 0;
}
early_initcall(init_sh_clocksource);
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