cpufreq_32.c

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/*
 *  Copyright (C) 2002 - 2005 Benjamin Herrenschmidt <[email protected]>
 *  Copyright (C) 2004        John Steele Scott <[email protected]>
 *
 * 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.
 *
 * TODO: Need a big cleanup here. Basically, we need to have different
 * cpufreq_driver structures for the different type of HW instead of the
 * current mess. We also need to better deal with the detection of the
 * type of machine.
 *
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/adb.h>
#include <linux/pmu.h>
#include <linux/cpufreq.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/hardirq.h>
#include <asm/prom.h>
#include <asm/machdep.h>
#include <asm/irq.h>
#include <asm/pmac_feature.h>
#include <asm/mmu_context.h>
#include <asm/sections.h>
#include <asm/cputable.h>
#include <asm/time.h>
#include <asm/mpic.h>
#include <asm/keylargo.h>
#include <asm/switch_to.h>

/* WARNING !!! This will cause calibrate_delay() to be called,
 * but this is an __init function ! So you MUST go edit
 * init/main.c to make it non-init before enabling DEBUG_FREQ
 */
#undef DEBUG_FREQ

extern void low_choose_7447a_dfs(int dfs);
extern void low_choose_750fx_pll(int pll);
extern void low_sleep_handler(void);

/*
 * Currently, PowerMac cpufreq supports only high & low frequencies
 * that are set by the firmware
 */
static unsigned int low_freq;
static unsigned int hi_freq;
static unsigned int cur_freq;
static unsigned int sleep_freq;

/*
 * Different models uses different mechanisms to switch the frequency
 */
static int (*set_speed_proc)(int low_speed);
static unsigned int (*get_speed_proc)(void);

/*
 * Some definitions used by the various speedprocs
 */
static u32 voltage_gpio;
static u32 frequency_gpio;
static u32 slew_done_gpio;
static int no_schedule;
static int has_cpu_l2lve;
static int is_pmu_based;

/* There are only two frequency states for each processor. Values
 * are in kHz for the time being.
 */
#define CPUFREQ_HIGH                  0
#define CPUFREQ_LOW                   1

static struct cpufreq_frequency_table pmac_cpu_freqs[] = {
    {CPUFREQ_HIGH,      0},
    {CPUFREQ_LOW,       0},
    {0,         CPUFREQ_TABLE_END},
};

static struct freq_attr* pmac_cpu_freqs_attr[] = {
    &cpufreq_freq_attr_scaling_available_freqs,
    NULL,
};

static inline void local_delay(unsigned long ms)
{
    if (no_schedule)
        mdelay(ms);
    else
        msleep(ms);
}

#ifdef DEBUG_FREQ
static inline void debug_calc_bogomips(void)
{
    /* This will cause a recalc of bogomips and display the
     * result. We backup/restore the value to avoid affecting the
     * core cpufreq framework's own calculation.
     */
    unsigned long save_lpj = loops_per_jiffy;
    calibrate_delay();
    loops_per_jiffy = save_lpj;
}
#endif /* DEBUG_FREQ */

/* Switch CPU speed under 750FX CPU control
 */
static int cpu_750fx_cpu_speed(int low_speed)
{
    u32 hid2;

    if (low_speed == 0) {
        /* ramping up, set voltage first */
        pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x05);
        /* Make sure we sleep for at least 1ms */
        local_delay(10);

        /* tweak L2 for high voltage */
        if (has_cpu_l2lve) {
            hid2 = mfspr(SPRN_HID2);
            hid2 &= ~0x2000;
            mtspr(SPRN_HID2, hid2);
        }
    }
#ifdef CONFIG_6xx
    low_choose_750fx_pll(low_speed);
#endif
    if (low_speed == 1) {
        /* tweak L2 for low voltage */
        if (has_cpu_l2lve) {
            hid2 = mfspr(SPRN_HID2);
            hid2 |= 0x2000;
            mtspr(SPRN_HID2, hid2);
        }

        /* ramping down, set voltage last */
        pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x04);
        local_delay(10);
    }

    return 0;
}

static unsigned int cpu_750fx_get_cpu_speed(void)
{
    if (mfspr(SPRN_HID1) & HID1_PS)
        return low_freq;
    else
        return hi_freq;
}

/* Switch CPU speed using DFS */
static int dfs_set_cpu_speed(int low_speed)
{
    if (low_speed == 0) {
        /* ramping up, set voltage first */
        pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x05);
        /* Make sure we sleep for at least 1ms */
        local_delay(1);
    }

    /* set frequency */
#ifdef CONFIG_6xx
    low_choose_7447a_dfs(low_speed);
#endif
    udelay(100);

    if (low_speed == 1) {
        /* ramping down, set voltage last */
        pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x04);
        local_delay(1);
    }

    return 0;
}

static unsigned int dfs_get_cpu_speed(void)
{
    if (mfspr(SPRN_HID1) & HID1_DFS)
        return low_freq;
    else
        return hi_freq;
}


/* Switch CPU speed using slewing GPIOs
 */
static int gpios_set_cpu_speed(int low_speed)
{
    int gpio, timeout = 0;

    /* If ramping up, set voltage first */
    if (low_speed == 0) {
        pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x05);
        /* Delay is way too big but it's ok, we schedule */
        local_delay(10);
    }

    /* Set frequency */
    gpio =  pmac_call_feature(PMAC_FTR_READ_GPIO, NULL, frequency_gpio, 0);
    if (low_speed == ((gpio & 0x01) == 0))
        goto skip;

    pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, frequency_gpio,
              low_speed ? 0x04 : 0x05);
    udelay(200);
    do {
        if (++timeout > 100)
            break;
        local_delay(1);
        gpio = pmac_call_feature(PMAC_FTR_READ_GPIO, NULL, slew_done_gpio, 0);
    } while((gpio & 0x02) == 0);
 skip:
    /* If ramping down, set voltage last */
    if (low_speed == 1) {
        pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x04);
        /* Delay is way too big but it's ok, we schedule */
        local_delay(10);
    }

#ifdef DEBUG_FREQ
    debug_calc_bogomips();
#endif

    return 0;
}

/* Switch CPU speed under PMU control
 */
static int pmu_set_cpu_speed(int low_speed)
{
    struct adb_request req;
    unsigned long save_l2cr;
    unsigned long save_l3cr;
    unsigned int pic_prio;
    unsigned long flags;

    preempt_disable();

#ifdef DEBUG_FREQ
    printk(KERN_DEBUG "HID1, before: %x\n", mfspr(SPRN_HID1));
#endif
    pmu_suspend();

    /* Disable all interrupt sources on openpic */
    pic_prio = mpic_cpu_get_priority();
    mpic_cpu_set_priority(0xf);

    /* Make sure the decrementer won't interrupt us */
    asm volatile("mtdec %0" : : "r" (0x7fffffff));
    /* Make sure any pending DEC interrupt occurring while we did
     * the above didn't re-enable the DEC */
    mb();
    asm volatile("mtdec %0" : : "r" (0x7fffffff));

    /* We can now disable MSR_EE */
    local_irq_save(flags);

    /* Giveup the FPU & vec */
    enable_kernel_fp();

#ifdef CONFIG_ALTIVEC
    if (cpu_has_feature(CPU_FTR_ALTIVEC))
        enable_kernel_altivec();
#endif /* CONFIG_ALTIVEC */

    /* Save & disable L2 and L3 caches */
    save_l3cr = _get_L3CR();    /* (returns -1 if not available) */
    save_l2cr = _get_L2CR();    /* (returns -1 if not available) */

    /* Send the new speed command. My assumption is that this command
     * will cause PLL_CFG[0..3] to be changed next time CPU goes to sleep
     */
    pmu_request(&req, NULL, 6, PMU_CPU_SPEED, 'W', 'O', 'O', 'F', low_speed);
    while (!req.complete)
        pmu_poll();

    /* Prepare the northbridge for the speed transition */
    pmac_call_feature(PMAC_FTR_SLEEP_STATE,NULL,1,1);

    /* Call low level code to backup CPU state and recover from
     * hardware reset
     */
    low_sleep_handler();

    /* Restore the northbridge */
    pmac_call_feature(PMAC_FTR_SLEEP_STATE,NULL,1,0);

    /* Restore L2 cache */
    if (save_l2cr != 0xffffffff && (save_l2cr & L2CR_L2E) != 0)
        _set_L2CR(save_l2cr);
    /* Restore L3 cache */
    if (save_l3cr != 0xffffffff && (save_l3cr & L3CR_L3E) != 0)
        _set_L3CR(save_l3cr);

    /* Restore userland MMU context */
    switch_mmu_context(NULL, current->active_mm);

#ifdef DEBUG_FREQ
    printk(KERN_DEBUG "HID1, after: %x\n", mfspr(SPRN_HID1));
#endif

    /* Restore low level PMU operations */
    pmu_unlock();

    /*
     * Restore decrementer; we'll take a decrementer interrupt
     * as soon as interrupts are re-enabled and the generic
     * clockevents code will reprogram it with the right value.
     */
    set_dec(1);

    /* Restore interrupts */
    mpic_cpu_set_priority(pic_prio);

    /* Let interrupts flow again ... */
    local_irq_restore(flags);

#ifdef DEBUG_FREQ
    debug_calc_bogomips();
#endif

    pmu_resume();

    preempt_enable();

    return 0;
}

static int do_set_cpu_speed(int speed_mode, int notify)
{
    struct cpufreq_freqs freqs;
    unsigned long l3cr;
    static unsigned long prev_l3cr;

    freqs.old = cur_freq;
    freqs.new = (speed_mode == CPUFREQ_HIGH) ? hi_freq : low_freq;
    freqs.cpu = smp_processor_id();

    if (freqs.old == freqs.new)
        return 0;

    if (notify)
        cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
    if (speed_mode == CPUFREQ_LOW &&
        cpu_has_feature(CPU_FTR_L3CR)) {
        l3cr = _get_L3CR();
        if (l3cr & L3CR_L3E) {
            prev_l3cr = l3cr;
            _set_L3CR(0);
        }
    }
    set_speed_proc(speed_mode == CPUFREQ_LOW);
    if (speed_mode == CPUFREQ_HIGH &&
        cpu_has_feature(CPU_FTR_L3CR)) {
        l3cr = _get_L3CR();
        if ((prev_l3cr & L3CR_L3E) && l3cr != prev_l3cr)
            _set_L3CR(prev_l3cr);
    }
    if (notify)
        cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
    cur_freq = (speed_mode == CPUFREQ_HIGH) ? hi_freq : low_freq;

    return 0;
}

static unsigned int pmac_cpufreq_get_speed(unsigned int cpu)
{
    return cur_freq;
}

static int pmac_cpufreq_verify(struct cpufreq_policy *policy)
{
    return cpufreq_frequency_table_verify(policy, pmac_cpu_freqs);
}

static int pmac_cpufreq_target( struct cpufreq_policy *policy,
                    unsigned int target_freq,
                    unsigned int relation)
{
    unsigned int    newstate = 0;
    int     rc;

    if (cpufreq_frequency_table_target(policy, pmac_cpu_freqs,
            target_freq, relation, &newstate))
        return -EINVAL;

    rc = do_set_cpu_speed(newstate, 1);

    ppc_proc_freq = cur_freq * 1000ul;
    return rc;
}

static int pmac_cpufreq_cpu_init(struct cpufreq_policy *policy)
{
    if (policy->cpu != 0)
        return -ENODEV;

    policy->cpuinfo.transition_latency  = CPUFREQ_ETERNAL;
    policy->cur = cur_freq;

    cpufreq_frequency_table_get_attr(pmac_cpu_freqs, policy->cpu);
    return cpufreq_frequency_table_cpuinfo(policy, pmac_cpu_freqs);
}

static u32 read_gpio(struct device_node *np)
{
    const u32 *reg = of_get_property(np, "reg", NULL);
    u32 offset;

    if (reg == NULL)
        return 0;
    /* That works for all keylargos but shall be fixed properly
     * some day... The problem is that it seems we can't rely
     * on the "reg" property of the GPIO nodes, they are either
     * relative to the base of KeyLargo or to the base of the
     * GPIO space, and the device-tree doesn't help.
     */
    offset = *reg;
    if (offset < KEYLARGO_GPIO_LEVELS0)
        offset += KEYLARGO_GPIO_LEVELS0;
    return offset;
}

static int pmac_cpufreq_suspend(struct cpufreq_policy *policy)
{
    /* Ok, this could be made a bit smarter, but let's be robust for now. We
     * always force a speed change to high speed before sleep, to make sure
     * we have appropriate voltage and/or bus speed for the wakeup process,
     * and to make sure our loops_per_jiffies are "good enough", that is will
     * not cause too short delays if we sleep in low speed and wake in high
     * speed..
     */
    no_schedule = 1;
    sleep_freq = cur_freq;
    if (cur_freq == low_freq && !is_pmu_based)
        do_set_cpu_speed(CPUFREQ_HIGH, 0);
    return 0;
}

static int pmac_cpufreq_resume(struct cpufreq_policy *policy)
{
    /* If we resume, first check if we have a get() function */
    if (get_speed_proc)
        cur_freq = get_speed_proc();
    else
        cur_freq = 0;

    /* We don't, hrm... we don't really know our speed here, best
     * is that we force a switch to whatever it was, which is
     * probably high speed due to our suspend() routine
     */
    do_set_cpu_speed(sleep_freq == low_freq ?
             CPUFREQ_LOW : CPUFREQ_HIGH, 0);

    ppc_proc_freq = cur_freq * 1000ul;

    no_schedule = 0;
    return 0;
}

static struct cpufreq_driver pmac_cpufreq_driver = {
    .verify     = pmac_cpufreq_verify,
    .target     = pmac_cpufreq_target,
    .get        = pmac_cpufreq_get_speed,
    .init       = pmac_cpufreq_cpu_init,
    .suspend    = pmac_cpufreq_suspend,
    .resume     = pmac_cpufreq_resume,
    .flags      = CPUFREQ_PM_NO_WARN,
    .attr       = pmac_cpu_freqs_attr,
    .name       = "powermac",
    .owner      = THIS_MODULE,
};


static int pmac_cpufreq_init_MacRISC3(struct device_node *cpunode)
{
    struct device_node *volt_gpio_np = of_find_node_by_name(NULL,
                                "voltage-gpio");
    struct device_node *freq_gpio_np = of_find_node_by_name(NULL,
                                "frequency-gpio");
    struct device_node *slew_done_gpio_np = of_find_node_by_name(NULL,
                                     "slewing-done");
    const u32 *value;

    /*
     * Check to see if it's GPIO driven or PMU only
     *
     * The way we extract the GPIO address is slightly hackish, but it
     * works well enough for now. We need to abstract the whole GPIO
     * stuff sooner or later anyway
     */

    if (volt_gpio_np)
        voltage_gpio = read_gpio(volt_gpio_np);
    if (freq_gpio_np)
        frequency_gpio = read_gpio(freq_gpio_np);
    if (slew_done_gpio_np)
        slew_done_gpio = read_gpio(slew_done_gpio_np);

    /* If we use the frequency GPIOs, calculate the min/max speeds based
     * on the bus frequencies
     */
    if (frequency_gpio && slew_done_gpio) {
        int lenp, rc;
        const u32 *freqs, *ratio;

        freqs = of_get_property(cpunode, "bus-frequencies", &lenp);
        lenp /= sizeof(u32);
        if (freqs == NULL || lenp != 2) {
            printk(KERN_ERR "cpufreq: bus-frequencies incorrect or missing\n");
            return 1;
        }
        ratio = of_get_property(cpunode, "processor-to-bus-ratio*2",
                        NULL);
        if (ratio == NULL) {
            printk(KERN_ERR "cpufreq: processor-to-bus-ratio*2 missing\n");
            return 1;
        }

        /* Get the min/max bus frequencies */
        low_freq = min(freqs[0], freqs[1]);
        hi_freq = max(freqs[0], freqs[1]);

        /* Grrrr.. It _seems_ that the device-tree is lying on the low bus
         * frequency, it claims it to be around 84Mhz on some models while
         * it appears to be approx. 101Mhz on all. Let's hack around here...
         * fortunately, we don't need to be too precise
         */
        if (low_freq < 98000000)
            low_freq = 101000000;

        /* Convert those to CPU core clocks */
        low_freq = (low_freq * (*ratio)) / 2000;
        hi_freq = (hi_freq * (*ratio)) / 2000;

        /* Now we get the frequencies, we read the GPIO to see what is out current
         * speed
         */
        rc = pmac_call_feature(PMAC_FTR_READ_GPIO, NULL, frequency_gpio, 0);
        cur_freq = (rc & 0x01) ? hi_freq : low_freq;

        set_speed_proc = gpios_set_cpu_speed;
        return 1;
    }

    /* If we use the PMU, look for the min & max frequencies in the
     * device-tree
     */
    value = of_get_property(cpunode, "min-clock-frequency", NULL);
    if (!value)
        return 1;
    low_freq = (*value) / 1000;
    /* The PowerBook G4 12" (PowerBook6,1) has an error in the device-tree
     * here */
    if (low_freq < 100000)
        low_freq *= 10;

    value = of_get_property(cpunode, "max-clock-frequency", NULL);
    if (!value)
        return 1;
    hi_freq = (*value) / 1000;
    set_speed_proc = pmu_set_cpu_speed;
    is_pmu_based = 1;

    return 0;
}

static int pmac_cpufreq_init_7447A(struct device_node *cpunode)
{
    struct device_node *volt_gpio_np;

    if (of_get_property(cpunode, "dynamic-power-step", NULL) == NULL)
        return 1;

    volt_gpio_np = of_find_node_by_name(NULL, "cpu-vcore-select");
    if (volt_gpio_np)
        voltage_gpio = read_gpio(volt_gpio_np);
    if (!voltage_gpio){
        printk(KERN_ERR "cpufreq: missing cpu-vcore-select gpio\n");
        return 1;
    }

    /* OF only reports the high frequency */
    hi_freq = cur_freq;
    low_freq = cur_freq/2;

    /* Read actual frequency from CPU */
    cur_freq = dfs_get_cpu_speed();
    set_speed_proc = dfs_set_cpu_speed;
    get_speed_proc = dfs_get_cpu_speed;

    return 0;
}

static int pmac_cpufreq_init_750FX(struct device_node *cpunode)
{
    struct device_node *volt_gpio_np;
    u32 pvr;
    const u32 *value;

    if (of_get_property(cpunode, "dynamic-power-step", NULL) == NULL)
        return 1;

    hi_freq = cur_freq;
    value = of_get_property(cpunode, "reduced-clock-frequency", NULL);
    if (!value)
        return 1;
    low_freq = (*value) / 1000;

    volt_gpio_np = of_find_node_by_name(NULL, "cpu-vcore-select");
    if (volt_gpio_np)
        voltage_gpio = read_gpio(volt_gpio_np);

    pvr = mfspr(SPRN_PVR);
    has_cpu_l2lve = !((pvr & 0xf00) == 0x100);

    set_speed_proc = cpu_750fx_cpu_speed;
    get_speed_proc = cpu_750fx_get_cpu_speed;
    cur_freq = cpu_750fx_get_cpu_speed();

    return 0;
}

/* Currently, we support the following machines:
 *
 *  - Titanium PowerBook 1Ghz (PMU based, 667Mhz & 1Ghz)
 *  - Titanium PowerBook 800 (PMU based, 667Mhz & 800Mhz)
 *  - Titanium PowerBook 400 (PMU based, 300Mhz & 400Mhz)
 *  - Titanium PowerBook 500 (PMU based, 300Mhz & 500Mhz)
 *  - iBook2 500/600 (PMU based, 400Mhz & 500/600Mhz)
 *  - iBook2 700 (CPU based, 400Mhz & 700Mhz, support low voltage)
 *  - Recent MacRISC3 laptops
 *  - All new machines with 7447A CPUs
 */
static int __init pmac_cpufreq_setup(void)
{
    struct device_node  *cpunode;
    const u32       *value;

    if (strstr(cmd_line, "nocpufreq"))
        return 0;

    /* Assume only one CPU */
    cpunode = of_find_node_by_type(NULL, "cpu");
    if (!cpunode)
        goto out;

    /* Get current cpu clock freq */
    value = of_get_property(cpunode, "clock-frequency", NULL);
    if (!value)
        goto out;
    cur_freq = (*value) / 1000;

    /*  Check for 7447A based MacRISC3 */
    if (of_machine_is_compatible("MacRISC3") &&
        of_get_property(cpunode, "dynamic-power-step", NULL) &&
        PVR_VER(mfspr(SPRN_PVR)) == 0x8003) {
        pmac_cpufreq_init_7447A(cpunode);
    /* Check for other MacRISC3 machines */
    } else if (of_machine_is_compatible("PowerBook3,4") ||
           of_machine_is_compatible("PowerBook3,5") ||
           of_machine_is_compatible("MacRISC3")) {
        pmac_cpufreq_init_MacRISC3(cpunode);
    /* Else check for iBook2 500/600 */
    } else if (of_machine_is_compatible("PowerBook4,1")) {
        hi_freq = cur_freq;
        low_freq = 400000;
        set_speed_proc = pmu_set_cpu_speed;
        is_pmu_based = 1;
    }
    /* Else check for TiPb 550 */
    else if (of_machine_is_compatible("PowerBook3,3") && cur_freq == 550000) {
        hi_freq = cur_freq;
        low_freq = 500000;
        set_speed_proc = pmu_set_cpu_speed;
        is_pmu_based = 1;
    }
    /* Else check for TiPb 400 & 500 */
    else if (of_machine_is_compatible("PowerBook3,2")) {
        /* We only know about the 400 MHz and the 500Mhz model
         * they both have 300 MHz as low frequency
         */
        if (cur_freq < 350000 || cur_freq > 550000)
            goto out;
        hi_freq = cur_freq;
        low_freq = 300000;
        set_speed_proc = pmu_set_cpu_speed;
        is_pmu_based = 1;
    }
    /* Else check for 750FX */
    else if (PVR_VER(mfspr(SPRN_PVR)) == 0x7000)
        pmac_cpufreq_init_750FX(cpunode);
out:
    of_node_put(cpunode);
    if (set_speed_proc == NULL)
        return -ENODEV;

    pmac_cpu_freqs[CPUFREQ_LOW].frequency = low_freq;
    pmac_cpu_freqs[CPUFREQ_HIGH].frequency = hi_freq;
    ppc_proc_freq = cur_freq * 1000ul;

    printk(KERN_INFO "Registering PowerMac CPU frequency driver\n");
    printk(KERN_INFO "Low: %d Mhz, High: %d Mhz, Boot: %d Mhz\n",
           low_freq/1000, hi_freq/1000, cur_freq/1000);

    return cpufreq_register_driver(&pmac_cpufreq_driver);
}

module_init(pmac_cpufreq_setup);