diff options
author | Ben Dooks <ben@simtec.co.uk> | 2009-07-30 23:23:21 +0100 |
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committer | Ben Dooks <ben-linux@fluff.org> | 2009-07-30 23:22:51 +0100 |
commit | 2e4ea6e8209e0c1d93c69c34c32002337b3f747e (patch) | |
tree | 11f2a4291e5cfbc7444d225eedd415bc9e9d23a9 /arch/arm/plat-s3c24xx/cpu-freq.c | |
parent | b0e66522f4d86713b0450255210e26c4f11ee86b (diff) | |
download | kernel_samsung_tuna-2e4ea6e8209e0c1d93c69c34c32002337b3f747e.zip kernel_samsung_tuna-2e4ea6e8209e0c1d93c69c34c32002337b3f747e.tar.gz kernel_samsung_tuna-2e4ea6e8209e0c1d93c69c34c32002337b3f747e.tar.bz2 |
ARM: S3C24XX: CPUFREQ: Add core support.
Add the core of the support for enabling the CPUFreq driver on
all S3C24XX based systems.
Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Diffstat (limited to 'arch/arm/plat-s3c24xx/cpu-freq.c')
-rw-r--r-- | arch/arm/plat-s3c24xx/cpu-freq.c | 704 |
1 files changed, 704 insertions, 0 deletions
diff --git a/arch/arm/plat-s3c24xx/cpu-freq.c b/arch/arm/plat-s3c24xx/cpu-freq.c new file mode 100644 index 0000000..40ff7e2 --- /dev/null +++ b/arch/arm/plat-s3c24xx/cpu-freq.c @@ -0,0 +1,704 @@ +/* linux/arch/arm/plat-s3c24xx/cpu-freq.c + * + * Copyright (c) 2006,2007,2008 Simtec Electronics + * http://armlinux.simtec.co.uk/ + * Ben Dooks <ben@simtec.co.uk> + * + * S3C24XX CPU Frequency scaling + * + * 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/interrupt.h> +#include <linux/ioport.h> +#include <linux/cpufreq.h> +#include <linux/cpu.h> +#include <linux/clk.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/sysdev.h> +#include <linux/kobject.h> +#include <linux/sysfs.h> + +#include <asm/mach/arch.h> +#include <asm/mach/map.h> + +#include <plat/cpu.h> +#include <plat/clock.h> +#include <plat/cpu-freq-core.h> + +#include <mach/regs-clock.h> + +/* note, cpufreq support deals in kHz, no Hz */ + +static struct cpufreq_driver s3c24xx_driver; +static struct s3c_cpufreq_config cpu_cur; +static struct s3c_iotimings s3c24xx_iotiming; +static struct cpufreq_frequency_table *pll_reg; +static unsigned int last_target = ~0; +static unsigned int ftab_size; +static struct cpufreq_frequency_table *ftab; + +static struct clk *_clk_mpll; +static struct clk *_clk_xtal; +static struct clk *clk_fclk; +static struct clk *clk_hclk; +static struct clk *clk_pclk; +static struct clk *clk_arm; + +static void s3c_cpufreq_getcur(struct s3c_cpufreq_config *cfg) +{ + unsigned long fclk, pclk, hclk, armclk; + + cfg->freq.fclk = fclk = clk_get_rate(clk_fclk); + cfg->freq.hclk = hclk = clk_get_rate(clk_hclk); + cfg->freq.pclk = pclk = clk_get_rate(clk_pclk); + cfg->freq.armclk = armclk = clk_get_rate(clk_arm); + + cfg->pll.index = __raw_readl(S3C2410_MPLLCON); + cfg->pll.frequency = fclk; + + cfg->freq.hclk_tns = 1000000000 / (cfg->freq.hclk / 10); + + cfg->divs.h_divisor = fclk / hclk; + cfg->divs.p_divisor = fclk / pclk; +} + +static inline void s3c_cpufreq_calc(struct s3c_cpufreq_config *cfg) +{ + unsigned long pll = cfg->pll.frequency; + + cfg->freq.fclk = pll; + cfg->freq.hclk = pll / cfg->divs.h_divisor; + cfg->freq.pclk = pll / cfg->divs.p_divisor; + + /* convert hclk into 10ths of nanoseconds for io calcs */ + cfg->freq.hclk_tns = 1000000000 / (cfg->freq.hclk / 10); +} + +static inline int closer(unsigned int target, unsigned int n, unsigned int c) +{ + int diff_cur = abs(target - c); + int diff_new = abs(target - n); + + return (diff_new < diff_cur); +} + +static void s3c_cpufreq_show(const char *pfx, + struct s3c_cpufreq_config *cfg) +{ + s3c_freq_dbg("%s: Fvco=%u, F=%lu, A=%lu, H=%lu (%u), P=%lu (%u)\n", + pfx, cfg->pll.frequency, cfg->freq.fclk, cfg->freq.armclk, + cfg->freq.hclk, cfg->divs.h_divisor, + cfg->freq.pclk, cfg->divs.p_divisor); +} + +/* functions to wrapper the driver info calls to do the cpu specific work */ + +static void s3c_cpufreq_setio(struct s3c_cpufreq_config *cfg) +{ + if (cfg->info->set_iotiming) + (cfg->info->set_iotiming)(cfg, &s3c24xx_iotiming); +} + +static int s3c_cpufreq_calcio(struct s3c_cpufreq_config *cfg) +{ + if (cfg->info->calc_iotiming) + return (cfg->info->calc_iotiming)(cfg, &s3c24xx_iotiming); + + return 0; +} + +static void s3c_cpufreq_setrefresh(struct s3c_cpufreq_config *cfg) +{ + (cfg->info->set_refresh)(cfg); +} + +static void s3c_cpufreq_setdivs(struct s3c_cpufreq_config *cfg) +{ + (cfg->info->set_divs)(cfg); +} + +static int s3c_cpufreq_calcdivs(struct s3c_cpufreq_config *cfg) +{ + return (cfg->info->calc_divs)(cfg); +} + +static void s3c_cpufreq_setfvco(struct s3c_cpufreq_config *cfg) +{ + (cfg->info->set_fvco)(cfg); +} + +static inline void s3c_cpufreq_resume_clocks(void) +{ + cpu_cur.info->resume_clocks(); +} + +static inline void s3c_cpufreq_updateclk(struct clk *clk, + unsigned int freq) +{ + clk_set_rate(clk, freq); +} + +static int s3c_cpufreq_settarget(struct cpufreq_policy *policy, + unsigned int target_freq, + struct cpufreq_frequency_table *pll) +{ + struct s3c_cpufreq_freqs freqs; + struct s3c_cpufreq_config cpu_new; + unsigned long flags; + + cpu_new = cpu_cur; /* copy new from current */ + + s3c_cpufreq_show("cur", &cpu_cur); + + /* TODO - check for DMA currently outstanding */ + + cpu_new.pll = pll ? *pll : cpu_cur.pll; + + if (pll) + freqs.pll_changing = 1; + + /* update our frequencies */ + + cpu_new.freq.armclk = target_freq; + cpu_new.freq.fclk = cpu_new.pll.frequency; + + if (s3c_cpufreq_calcdivs(&cpu_new) < 0) { + printk(KERN_ERR "no divisors for %d\n", target_freq); + goto err_notpossible; + } + + s3c_freq_dbg("%s: got divs\n", __func__); + + s3c_cpufreq_calc(&cpu_new); + + s3c_freq_dbg("%s: calculated frequencies for new\n", __func__); + + if (cpu_new.freq.hclk != cpu_cur.freq.hclk) { + if (s3c_cpufreq_calcio(&cpu_new) < 0) { + printk(KERN_ERR "%s: no IO timings\n", __func__); + goto err_notpossible; + } + } + + s3c_cpufreq_show("new", &cpu_new); + + /* setup our cpufreq parameters */ + + freqs.old = cpu_cur.freq; + freqs.new = cpu_new.freq; + + freqs.freqs.cpu = 0; + freqs.freqs.old = cpu_cur.freq.armclk / 1000; + freqs.freqs.new = cpu_new.freq.armclk / 1000; + + /* update f/h/p clock settings before we issue the change + * notification, so that drivers do not need to do anything + * special if they want to recalculate on CPUFREQ_PRECHANGE. */ + + s3c_cpufreq_updateclk(_clk_mpll, cpu_new.pll.frequency); + s3c_cpufreq_updateclk(clk_fclk, cpu_new.freq.fclk); + s3c_cpufreq_updateclk(clk_hclk, cpu_new.freq.hclk); + s3c_cpufreq_updateclk(clk_pclk, cpu_new.freq.pclk); + + /* start the frequency change */ + + if (policy) + cpufreq_notify_transition(&freqs.freqs, CPUFREQ_PRECHANGE); + + /* If hclk is staying the same, then we do not need to + * re-write the IO or the refresh timings whilst we are changing + * speed. */ + + local_irq_save(flags); + + /* is our memory clock slowing down? */ + if (cpu_new.freq.hclk < cpu_cur.freq.hclk) { + s3c_cpufreq_setrefresh(&cpu_new); + s3c_cpufreq_setio(&cpu_new); + } + + if (cpu_new.freq.fclk == cpu_cur.freq.fclk) { + /* not changing PLL, just set the divisors */ + + s3c_cpufreq_setdivs(&cpu_new); + } else { + if (cpu_new.freq.fclk < cpu_cur.freq.fclk) { + /* slow the cpu down, then set divisors */ + + s3c_cpufreq_setfvco(&cpu_new); + s3c_cpufreq_setdivs(&cpu_new); + } else { + /* set the divisors, then speed up */ + + s3c_cpufreq_setdivs(&cpu_new); + s3c_cpufreq_setfvco(&cpu_new); + } + } + + /* did our memory clock speed up */ + if (cpu_new.freq.hclk > cpu_cur.freq.hclk) { + s3c_cpufreq_setrefresh(&cpu_new); + s3c_cpufreq_setio(&cpu_new); + } + + /* update our current settings */ + cpu_cur = cpu_new; + + local_irq_restore(flags); + + /* notify everyone we've done this */ + if (policy) + cpufreq_notify_transition(&freqs.freqs, CPUFREQ_POSTCHANGE); + + s3c_freq_dbg("%s: finished\n", __func__); + return 0; + + err_notpossible: + printk(KERN_ERR "no compatible settings for %d\n", target_freq); + return -EINVAL; +} + +/* s3c_cpufreq_target + * + * called by the cpufreq core to adjust the frequency that the CPU + * is currently running at. + */ + +static int s3c_cpufreq_target(struct cpufreq_policy *policy, + unsigned int target_freq, + unsigned int relation) +{ + struct cpufreq_frequency_table *pll; + unsigned int index; + + /* avoid repeated calls which cause a needless amout of duplicated + * logging output (and CPU time as the calculation process is + * done) */ + if (target_freq == last_target) + return 0; + + last_target = target_freq; + + s3c_freq_dbg("%s: policy %p, target %u, relation %u\n", + __func__, policy, target_freq, relation); + + if (ftab) { + if (cpufreq_frequency_table_target(policy, ftab, + target_freq, relation, + &index)) { + s3c_freq_dbg("%s: table failed\n", __func__); + return -EINVAL; + } + + s3c_freq_dbg("%s: adjust %d to entry %d (%u)\n", __func__, + target_freq, index, ftab[index].frequency); + target_freq = ftab[index].frequency; + } + + target_freq *= 1000; /* convert target to Hz */ + + /* find the settings for our new frequency */ + + if (!pll_reg || cpu_cur.lock_pll) { + /* either we've not got any PLL values, or we've locked + * to the current one. */ + pll = NULL; + } else { + struct cpufreq_policy tmp_policy; + int ret; + + /* we keep the cpu pll table in Hz, to ensure we get an + * accurate value for the PLL output. */ + + tmp_policy.min = policy->min * 1000; + tmp_policy.max = policy->max * 1000; + tmp_policy.cpu = policy->cpu; + + /* cpufreq_frequency_table_target uses a pointer to 'index' + * which is the number of the table entry, not the value of + * the table entry's index field. */ + + ret = cpufreq_frequency_table_target(&tmp_policy, pll_reg, + target_freq, relation, + &index); + + if (ret < 0) { + printk(KERN_ERR "%s: no PLL available\n", __func__); + goto err_notpossible; + } + + pll = pll_reg + index; + + s3c_freq_dbg("%s: target %u => %u\n", + __func__, target_freq, pll->frequency); + + target_freq = pll->frequency; + } + + return s3c_cpufreq_settarget(policy, target_freq, pll); + + err_notpossible: + printk(KERN_ERR "no compatible settings for %d\n", target_freq); + return -EINVAL; +} + +static unsigned int s3c_cpufreq_get(unsigned int cpu) +{ + return clk_get_rate(clk_arm) / 1000; +} + +struct clk *s3c_cpufreq_clk_get(struct device *dev, const char *name) +{ + struct clk *clk; + + clk = clk_get(dev, name); + if (IS_ERR(clk)) + printk(KERN_ERR "cpufreq: failed to get clock '%s'\n", name); + + return clk; +} + +static int s3c_cpufreq_init(struct cpufreq_policy *policy) +{ + printk(KERN_INFO "%s: initialising policy %p\n", __func__, policy); + + if (policy->cpu != 0) + return -EINVAL; + + policy->cur = s3c_cpufreq_get(0); + policy->min = policy->cpuinfo.min_freq = 0; + policy->max = policy->cpuinfo.max_freq = cpu_cur.info->max.fclk / 1000; + policy->governor = CPUFREQ_DEFAULT_GOVERNOR; + + /* feed the latency information from the cpu driver */ + policy->cpuinfo.transition_latency = cpu_cur.info->latency; + + if (ftab) + cpufreq_frequency_table_cpuinfo(policy, ftab); + + return 0; +} + +static __init int s3c_cpufreq_initclks(void) +{ + _clk_mpll = s3c_cpufreq_clk_get(NULL, "mpll"); + _clk_xtal = s3c_cpufreq_clk_get(NULL, "xtal"); + clk_fclk = s3c_cpufreq_clk_get(NULL, "fclk"); + clk_hclk = s3c_cpufreq_clk_get(NULL, "hclk"); + clk_pclk = s3c_cpufreq_clk_get(NULL, "pclk"); + clk_arm = s3c_cpufreq_clk_get(NULL, "armclk"); + + if (IS_ERR(clk_fclk) || IS_ERR(clk_hclk) || IS_ERR(clk_pclk) || + IS_ERR(_clk_mpll) || IS_ERR(clk_arm) || IS_ERR(_clk_xtal)) { + printk(KERN_ERR "%s: could not get clock(s)\n", __func__); + return -ENOENT; + } + + printk(KERN_INFO "%s: clocks f=%lu,h=%lu,p=%lu,a=%lu\n", __func__, + clk_get_rate(clk_fclk) / 1000, + clk_get_rate(clk_hclk) / 1000, + clk_get_rate(clk_pclk) / 1000, + clk_get_rate(clk_arm) / 1000); + + return 0; +} + +static int s3c_cpufreq_verify(struct cpufreq_policy *policy) +{ + if (policy->cpu != 0) + return -EINVAL; + + return 0; +} + +#ifdef CONFIG_PM +static struct cpufreq_frequency_table suspend_pll; +static unsigned int suspend_freq; + +static int s3c_cpufreq_suspend(struct cpufreq_policy *policy, pm_message_t pmsg) +{ + suspend_pll.frequency = clk_get_rate(_clk_mpll); + suspend_pll.index = __raw_readl(S3C2410_MPLLCON); + suspend_freq = s3c_cpufreq_get(0) * 1000; + + return 0; +} + +static int s3c_cpufreq_resume(struct cpufreq_policy *policy) +{ + int ret; + + s3c_freq_dbg("%s: resuming with policy %p\n", __func__, policy); + + last_target = ~0; /* invalidate last_target setting */ + + /* first, find out what speed we resumed at. */ + s3c_cpufreq_resume_clocks(); + + /* whilst we will be called later on, we try and re-set the + * cpu frequencies as soon as possible so that we do not end + * up resuming devices and then immediatley having to re-set + * a number of settings once these devices have restarted. + * + * as a note, it is expected devices are not used until they + * have been un-suspended and at that time they should have + * used the updated clock settings. + */ + + ret = s3c_cpufreq_settarget(NULL, suspend_freq, &suspend_pll); + if (ret) { + printk(KERN_ERR "%s: failed to reset pll/freq\n", __func__); + return ret; + } + + return 0; +} +#else +#define s3c_cpufreq_resume NULL +#define s3c_cpufreq_suspend NULL +#endif + +static struct cpufreq_driver s3c24xx_driver = { + .flags = CPUFREQ_STICKY, + .verify = s3c_cpufreq_verify, + .target = s3c_cpufreq_target, + .get = s3c_cpufreq_get, + .init = s3c_cpufreq_init, + .suspend = s3c_cpufreq_suspend, + .resume = s3c_cpufreq_resume, + .name = "s3c24xx", +}; + + +int __init s3c_cpufreq_register(struct s3c_cpufreq_info *info) +{ + if (!info || !info->name) { + printk(KERN_ERR "%s: failed to pass valid information\n", + __func__); + return -EINVAL; + } + + printk(KERN_INFO "S3C24XX CPU Frequency driver, %s cpu support\n", + info->name); + + /* check our driver info has valid data */ + + BUG_ON(info->set_refresh == NULL); + BUG_ON(info->set_divs == NULL); + BUG_ON(info->calc_divs == NULL); + + /* info->set_fvco is optional, depending on whether there + * is a need to set the clock code. */ + + cpu_cur.info = info; + + /* Note, driver registering should probably update locktime */ + + return 0; +} + +int __init s3c_cpufreq_setboard(struct s3c_cpufreq_board *board) +{ + struct s3c_cpufreq_board *ours; + + if (!board) { + printk(KERN_INFO "%s: no board data\n", __func__); + return -EINVAL; + } + + /* Copy the board information so that each board can make this + * initdata. */ + + ours = kzalloc(sizeof(struct s3c_cpufreq_board), GFP_KERNEL); + if (ours == NULL) { + printk(KERN_ERR "%s: no memory\n", __func__); + return -ENOMEM; + } + + *ours = *board; + cpu_cur.board = ours; + + return 0; +} + +int __init s3c_cpufreq_auto_io(void) +{ + int ret; + + if (!cpu_cur.info->get_iotiming) { + printk(KERN_ERR "%s: get_iotiming undefined\n", __func__); + return -ENOENT; + } + + printk(KERN_INFO "%s: working out IO settings\n", __func__); + + ret = (cpu_cur.info->get_iotiming)(&cpu_cur, &s3c24xx_iotiming); + if (ret) + printk(KERN_ERR "%s: failed to get timings\n", __func__); + + return ret; +} + +/* if one or is zero, then return the other, otherwise return the min */ +#define do_min(_a, _b) ((_a) == 0 ? (_b) : (_b) == 0 ? (_a) : min(_a, _b)) + +/** + * s3c_cpufreq_freq_min - find the minimum settings for the given freq. + * @dst: The destination structure + * @a: One argument. + * @b: The other argument. + * + * Create a minimum of each frequency entry in the 'struct s3c_freq', + * unless the entry is zero when it is ignored and the non-zero argument + * used. + */ +static void s3c_cpufreq_freq_min(struct s3c_freq *dst, + struct s3c_freq *a, struct s3c_freq *b) +{ + dst->fclk = do_min(a->fclk, b->fclk); + dst->hclk = do_min(a->hclk, b->hclk); + dst->pclk = do_min(a->pclk, b->pclk); + dst->armclk = do_min(a->armclk, b->armclk); +} + +static inline u32 calc_locktime(u32 freq, u32 time_us) +{ + u32 result; + + result = freq * time_us; + result = DIV_ROUND_UP(result, 1000 * 1000); + + return result; +} + +static void s3c_cpufreq_update_loctkime(void) +{ + unsigned int bits = cpu_cur.info->locktime_bits; + u32 rate = (u32)clk_get_rate(_clk_xtal); + u32 val; + + if (bits == 0) { + WARN_ON(1); + return; + } + + val = calc_locktime(rate, cpu_cur.info->locktime_u) << bits; + val |= calc_locktime(rate, cpu_cur.info->locktime_m); + + printk(KERN_INFO "%s: new locktime is 0x%08x\n", __func__, val); + __raw_writel(val, S3C2410_LOCKTIME); +} + +static int s3c_cpufreq_build_freq(void) +{ + int size, ret; + + if (!cpu_cur.info->calc_freqtable) + return -EINVAL; + + kfree(ftab); + ftab = NULL; + + size = cpu_cur.info->calc_freqtable(&cpu_cur, NULL, 0); + size++; + + ftab = kmalloc(sizeof(struct cpufreq_frequency_table) * size, GFP_KERNEL); + if (!ftab) { + printk(KERN_ERR "%s: no memory for tables\n", __func__); + return -ENOMEM; + } + + ftab_size = size; + + ret = cpu_cur.info->calc_freqtable(&cpu_cur, ftab, size); + s3c_cpufreq_addfreq(ftab, ret, size, CPUFREQ_TABLE_END); + + return 0; +} + +static int __init s3c_cpufreq_initcall(void) +{ + int ret = 0; + + if (cpu_cur.info && cpu_cur.board) { + ret = s3c_cpufreq_initclks(); + if (ret) + goto out; + + /* get current settings */ + s3c_cpufreq_getcur(&cpu_cur); + s3c_cpufreq_show("cur", &cpu_cur); + + if (cpu_cur.board->auto_io) { + ret = s3c_cpufreq_auto_io(); + if (ret) { + printk(KERN_ERR "%s: failed to get io timing\n", + __func__); + goto out; + } + } + + if (cpu_cur.board->need_io && !cpu_cur.info->set_iotiming) { + printk(KERN_ERR "%s: no IO support registered\n", + __func__); + ret = -EINVAL; + goto out; + } + + if (!cpu_cur.info->need_pll) + cpu_cur.lock_pll = 1; + + s3c_cpufreq_update_loctkime(); + + s3c_cpufreq_freq_min(&cpu_cur.max, &cpu_cur.board->max, + &cpu_cur.info->max); + + if (cpu_cur.info->calc_freqtable) + s3c_cpufreq_build_freq(); + + ret = cpufreq_register_driver(&s3c24xx_driver); + } + + out: + return ret; +} + +late_initcall(s3c_cpufreq_initcall); + +/** + * s3c_plltab_register - register CPU PLL table. + * @plls: The list of PLL entries. + * @plls_no: The size of the PLL entries @plls. + * + * Register the given set of PLLs with the system. + */ +int __init s3c_plltab_register(struct cpufreq_frequency_table *plls, + unsigned int plls_no) +{ + struct cpufreq_frequency_table *vals; + unsigned int size; + + size = sizeof(struct cpufreq_frequency_table) * (plls_no + 1); + + vals = kmalloc(size, GFP_KERNEL); + if (vals) { + memcpy(vals, plls, size); + pll_reg = vals; + + /* write a terminating entry, we don't store it in the + * table that is stored in the kernel */ + vals += plls_no; + vals->frequency = CPUFREQ_TABLE_END; + + printk(KERN_INFO "cpufreq: %d PLL entries\n", plls_no); + } else + printk(KERN_ERR "cpufreq: no memory for PLL tables\n"); + + return vals ? 0 : -ENOMEM; +} |