diff options
Diffstat (limited to 'arch/arm/plat-samsung/clock-clksrc.c')
| -rw-r--r-- | arch/arm/plat-samsung/clock-clksrc.c | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/arch/arm/plat-samsung/clock-clksrc.c b/arch/arm/plat-samsung/clock-clksrc.c new file mode 100644 index 00000000000..ae8b8507663 --- /dev/null +++ b/arch/arm/plat-samsung/clock-clksrc.c @@ -0,0 +1,212 @@ +/* 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); + } + } +} |