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/*
* 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/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/clk.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"
struct clk {
const char *name;
unsigned long rate;
unsigned long (*get_rate) (void);
};
static struct clk *cpu_clk;
static int cpu_clk_cnt;
/* lantiq socs have 3 static clocks */
static struct clk cpu_clk_generic[] = {
{
.name = "cpu",
.get_rate = ltq_get_cpu_hz,
}, {
.name = "fpi",
.get_rate = ltq_get_fpi_hz,
}, {
.name = "io",
.get_rate = ltq_get_io_region_clock,
},
};
static struct resource ltq_cgu_resource = {
.name = "cgu",
.start = LTQ_CGU_BASE_ADDR,
.end = LTQ_CGU_BASE_ADDR + LTQ_CGU_SIZE - 1,
.flags = IORESOURCE_MEM,
};
/* remapped clock register range */
void __iomem *ltq_cgu_membase;
void clk_init(void)
{
cpu_clk = cpu_clk_generic;
cpu_clk_cnt = ARRAY_SIZE(cpu_clk_generic);
}
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);
struct clk *clk_get(struct device *dev, const char *id)
{
int i;
for (i = 0; i < cpu_clk_cnt; i++)
if (!strcmp(id, cpu_clk[i].name))
return &cpu_clk[i];
BUG();
return ERR_PTR(-ENOENT);
}
EXPORT_SYMBOL(clk_get);
void clk_put(struct clk *clk)
{
/* not used */
}
EXPORT_SYMBOL(clk_put);
static inline u32 ltq_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;
if (insert_resource(&iomem_resource, <q_cgu_resource) < 0)
panic("Failed to insert cgu memory\n");
if (request_mem_region(ltq_cgu_resource.start,
resource_size(<q_cgu_resource), "cgu") < 0)
panic("Failed to request cgu memory\n");
ltq_cgu_membase = ioremap_nocache(ltq_cgu_resource.start,
resource_size(<q_cgu_resource));
if (!ltq_cgu_membase) {
pr_err("Failed to remap cgu memory\n");
unreachable();
}
clk = clk_get(0, "cpu");
mips_hpt_frequency = clk_get_rate(clk) / ltq_get_counter_resolution();
write_c0_compare(read_c0_count());
clk_put(clk);
}
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