cpu-freq.c

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/* linux/arch/arm/plat-s3c24xx/cpu-freq.c
 *
 * Copyright (c) 2006-2008 Simtec Electronics
 *  http://armlinux.simtec.co.uk/
 *  Ben Dooks <[email protected]>
 *
 * 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/device.h>
#include <linux/sysfs.h>
#include <linux/slab.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;

#ifdef CONFIG_CPU_FREQ_S3C24XX_DEBUGFS
struct s3c_cpufreq_config *s3c_cpufreq_getconfig(void)
{
    return &cpu_cur;
}

struct s3c_iotimings *s3c_cpufreq_getiotimings(void)
{
    return &s3c24xx_iotiming;
}
#endif /* CONFIG_CPU_FREQ_S3C24XX_DEBUGFS */

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)
{
    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 immediately 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))

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);

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;
}