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/* linux/arch/arm/plat-samsung/clock-clksrc.c
*
* Copyright 2008 Simtec Electronics
* Ben Dooks <ben@simtec.co.uk>
* http://armlinux.simtec.co.uk/
*
* 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.
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/sysdev.h>
#include <linux/io.h>
#include <plat/clock.h>
#include <plat/clock-clksrc.h>
#include <plat/cpu-freq.h>
static inline struct clksrc_clk *to_clksrc(struct clk *clk)
{
return container_of(clk, struct clksrc_clk, clk);
}
static inline u32 bit_mask(u32 shift, u32 nr_bits)
{
u32 mask = 0xffffffff >> (32 - nr_bits);
return mask << shift;
}
static unsigned long s3c_getrate_clksrc(struct clk *clk)
{
struct clksrc_clk *sclk = to_clksrc(clk);
unsigned long rate = clk_get_rate(clk->parent);
u32 clkdiv = __raw_readl(sclk->reg_div.reg);
u32 mask = bit_mask(sclk->reg_div.shift, sclk->reg_div.size);
clkdiv &= mask;
clkdiv >>= sclk->reg_div.shift;
clkdiv++;
rate /= clkdiv;
return rate;
}
static int s3c_setrate_clksrc(struct clk *clk, unsigned long rate)
{
struct clksrc_clk *sclk = to_clksrc(clk);
void __iomem *reg = sclk->reg_div.reg;
unsigned int div;
u32 mask = bit_mask(sclk->reg_div.shift, sclk->reg_div.size);
u32 val;
rate = clk_round_rate(clk, rate);
div = clk_get_rate(clk->parent) / rate;
if (div > (1 << sclk->reg_div.size))
return -EINVAL;
val = __raw_readl(reg);
val &= ~mask;
val |= (div - 1) << sclk->reg_div.shift;
__raw_writel(val, reg);
return 0;
}
static int s3c_setparent_clksrc(struct clk *clk, struct clk *parent)
{
struct clksrc_clk *sclk = to_clksrc(clk);
struct clksrc_sources *srcs = sclk->sources;
u32 clksrc = __raw_readl(sclk->reg_src.reg);
u32 mask = bit_mask(sclk->reg_src.shift, sclk->reg_src.size);
int src_nr = -1;
int ptr;
for (ptr = 0; ptr < srcs->nr_sources; ptr++)
if (srcs->sources[ptr] == parent) {
src_nr = ptr;
break;
}
if (src_nr >= 0) {
clk->parent = parent;
clksrc &= ~mask;
clksrc |= src_nr << sclk->reg_src.shift;
__raw_writel(clksrc, sclk->reg_src.reg);
return 0;
}
return -EINVAL;
}
static unsigned long s3c_roundrate_clksrc(struct clk *clk,
unsigned long rate)
{
struct clksrc_clk *sclk = to_clksrc(clk);
unsigned long parent_rate = clk_get_rate(clk->parent);
int max_div = 1 << sclk->reg_div.size;
int div;
if (rate >= parent_rate)
rate = parent_rate;
else {
div = parent_rate / rate;
if (parent_rate % rate)
div++;
if (div == 0)
div = 1;
if (div > max_div)
div = max_div;
rate = parent_rate / div;
}
return rate;
}
/* Clock initialisation code */
void __init_or_cpufreq s3c_set_clksrc(struct clksrc_clk *clk, bool announce)
{
struct clksrc_sources *srcs = clk->sources;
u32 mask = bit_mask(clk->reg_src.shift, clk->reg_src.size);
u32 clksrc;
if (!clk->reg_src.reg) {
if (!clk->clk.parent)
printk(KERN_ERR "%s: no parent clock specified\n",
clk->clk.name);
return;
}
clksrc = __raw_readl(clk->reg_src.reg);
clksrc &= mask;
clksrc >>= clk->reg_src.shift;
if (clksrc > srcs->nr_sources || !srcs->sources[clksrc]) {
printk(KERN_ERR "%s: bad source %d\n",
clk->clk.name, clksrc);
return;
}
clk->clk.parent = srcs->sources[clksrc];
if (announce)
printk(KERN_INFO "%s: source is %s (%d), rate is %ld\n",
clk->clk.name, clk->clk.parent->name, clksrc,
clk_get_rate(&clk->clk));
}
static struct clk_ops clksrc_ops = {
.set_parent = s3c_setparent_clksrc,
.get_rate = s3c_getrate_clksrc,
.set_rate = s3c_setrate_clksrc,
.round_rate = s3c_roundrate_clksrc,
};
static struct clk_ops clksrc_ops_nodiv = {
.set_parent = s3c_setparent_clksrc,
};
static struct clk_ops clksrc_ops_nosrc = {
.get_rate = s3c_getrate_clksrc,
.set_rate = s3c_setrate_clksrc,
.round_rate = s3c_roundrate_clksrc,
};
void __init s3c_register_clksrc(struct clksrc_clk *clksrc, int size)
{
int ret;
for (; size > 0; size--, clksrc++) {
if (!clksrc->reg_div.reg && !clksrc->reg_src.reg)
printk(KERN_ERR "%s: clock %s has no registers set\n",
__func__, clksrc->clk.name);
/* fill in the default functions */
if (!clksrc->clk.ops) {
if (!clksrc->reg_div.reg)
clksrc->clk.ops = &clksrc_ops_nodiv;
else if (!clksrc->reg_src.reg)
clksrc->clk.ops = &clksrc_ops_nosrc;
else
clksrc->clk.ops = &clksrc_ops;
}
/* setup the clocksource, but do not announce it
* as it may be re-set by the setup routines
* called after the rest of the clocks have been
* registered
*/
s3c_set_clksrc(clksrc, false);
ret = s3c24xx_register_clock(&clksrc->clk);
if (ret < 0) {
printk(KERN_ERR "%s: failed to register %s (%d)\n",
__func__, clksrc->clk.name, ret);
}
}
}
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