linux/arch/mips/lantiq/clk.c

166 lines
2.9 KiB
C

/*
* 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) 2010 Thomas Langer <thomas.langer@lantiq.com>
* Copyright (C) 2010 John Crispin <blogic@openwrt.org>
*/
#include <linux/io.h>
#include <linux/export.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/clk.h>
#include <linux/clkdev.h>
#include <linux/err.h>
#include <linux/list.h>
#include <asm/time.h>
#include <asm/irq.h>
#include <asm/div64.h>
#include <lantiq_soc.h>
#include "clk.h"
#include "prom.h"
/* lantiq socs have 3 static clocks */
static struct clk cpu_clk_generic[3];
void clkdev_add_static(unsigned long cpu, unsigned long fpi, unsigned long io)
{
cpu_clk_generic[0].rate = cpu;
cpu_clk_generic[1].rate = fpi;
cpu_clk_generic[2].rate = io;
}
struct clk *clk_get_cpu(void)
{
return &cpu_clk_generic[0];
}
struct clk *clk_get_fpi(void)
{
return &cpu_clk_generic[1];
}
EXPORT_SYMBOL_GPL(clk_get_fpi);
struct clk *clk_get_io(void)
{
return &cpu_clk_generic[2];
}
static inline int clk_good(struct clk *clk)
{
return clk && !IS_ERR(clk);
}
unsigned long clk_get_rate(struct clk *clk)
{
if (unlikely(!clk_good(clk)))
return 0;
if (clk->rate != 0)
return clk->rate;
if (clk->get_rate != NULL)
return clk->get_rate();
return 0;
}
EXPORT_SYMBOL(clk_get_rate);
int clk_set_rate(struct clk *clk, unsigned long rate)
{
if (unlikely(!clk_good(clk)))
return 0;
if (clk->rates && *clk->rates) {
unsigned long *r = clk->rates;
while (*r && (*r != rate))
r++;
if (!*r) {
pr_err("clk %s.%s: trying to set invalid rate %ld\n",
clk->cl.dev_id, clk->cl.con_id, rate);
return -1;
}
}
clk->rate = rate;
return 0;
}
EXPORT_SYMBOL(clk_set_rate);
int clk_enable(struct clk *clk)
{
if (unlikely(!clk_good(clk)))
return -1;
if (clk->enable)
return clk->enable(clk);
return -1;
}
EXPORT_SYMBOL(clk_enable);
void clk_disable(struct clk *clk)
{
if (unlikely(!clk_good(clk)))
return;
if (clk->disable)
clk->disable(clk);
}
EXPORT_SYMBOL(clk_disable);
int clk_activate(struct clk *clk)
{
if (unlikely(!clk_good(clk)))
return -1;
if (clk->activate)
return clk->activate(clk);
return -1;
}
EXPORT_SYMBOL(clk_activate);
void clk_deactivate(struct clk *clk)
{
if (unlikely(!clk_good(clk)))
return;
if (clk->deactivate)
clk->deactivate(clk);
}
EXPORT_SYMBOL(clk_deactivate);
static inline u32 get_counter_resolution(void)
{
u32 res;
__asm__ __volatile__(
".set push\n"
".set mips32r2\n"
"rdhwr %0, $3\n"
".set pop\n"
: "=&r" (res)
: /* no input */
: "memory");
return res;
}
void __init plat_time_init(void)
{
struct clk *clk;
ltq_soc_init();
clk = clk_get_cpu();
mips_hpt_frequency = clk_get_rate(clk) / get_counter_resolution();
write_c0_compare(read_c0_count());
pr_info("CPU Clock: %ldMHz\n", clk_get_rate(clk) / 1000000);
clk_put(clk);
}