clockdomain.c

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/*
 * OMAP2/3/4 clockdomain framework functions
 *
 * Copyright (C) 2008-2011 Texas Instruments, Inc.
 * Copyright (C) 2008-2011 Nokia Corporation
 *
 * Written by Paul Walmsley and Jouni Högander
 * Added OMAP4 specific support by Abhijit Pagare <[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.
 */
#undef DEBUG

#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/list.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/delay.h>
#include <linux/clk.h>
#include <linux/limits.h>
#include <linux/err.h>

#include <linux/io.h>

#include <linux/bitops.h>

#include <plat/clock.h>
#include "clockdomain.h"

/* clkdm_list contains all registered struct clockdomains */
static LIST_HEAD(clkdm_list);

/* array of clockdomain deps to be added/removed when clkdm in hwsup mode */
static struct clkdm_autodep *autodeps;

static struct clkdm_ops *arch_clkdm;

/* Private functions */

static struct clockdomain *_clkdm_lookup(const char *name)
{
    struct clockdomain *clkdm, *temp_clkdm;

    if (!name)
        return NULL;

    clkdm = NULL;

    list_for_each_entry(temp_clkdm, &clkdm_list, node) {
        if (!strcmp(name, temp_clkdm->name)) {
            clkdm = temp_clkdm;
            break;
        }
    }

    return clkdm;
}

static int _clkdm_register(struct clockdomain *clkdm)
{
    struct powerdomain *pwrdm;

    if (!clkdm || !clkdm->name)
        return -EINVAL;

    pwrdm = pwrdm_lookup(clkdm->pwrdm.name);
    if (!pwrdm) {
        pr_err("clockdomain: %s: powerdomain %s does not exist\n",
            clkdm->name, clkdm->pwrdm.name);
        return -EINVAL;
    }
    clkdm->pwrdm.ptr = pwrdm;

    /* Verify that the clockdomain is not already registered */
    if (_clkdm_lookup(clkdm->name))
        return -EEXIST;

    list_add(&clkdm->node, &clkdm_list);

    pwrdm_add_clkdm(pwrdm, clkdm);

    spin_lock_init(&clkdm->lock);

    pr_debug("clockdomain: registered %s\n", clkdm->name);

    return 0;
}

/* _clkdm_deps_lookup - look up the specified clockdomain in a clkdm list */
static struct clkdm_dep *_clkdm_deps_lookup(struct clockdomain *clkdm,
                        struct clkdm_dep *deps)
{
    struct clkdm_dep *cd;

    if (!clkdm || !deps)
        return ERR_PTR(-EINVAL);

    for (cd = deps; cd->clkdm_name; cd++) {
        if (!cd->clkdm && cd->clkdm_name)
            cd->clkdm = _clkdm_lookup(cd->clkdm_name);

        if (cd->clkdm == clkdm)
            break;
    }

    if (!cd->clkdm_name)
        return ERR_PTR(-ENOENT);

    return cd;
}

/*
 * _autodep_lookup - resolve autodep clkdm names to clkdm pointers; store
 * @autodep: struct clkdm_autodep * to resolve
 *
 * Resolve autodep clockdomain names to clockdomain pointers via
 * clkdm_lookup() and store the pointers in the autodep structure.  An
 * "autodep" is a clockdomain sleep/wakeup dependency that is
 * automatically added and removed whenever clocks in the associated
 * clockdomain are enabled or disabled (respectively) when the
 * clockdomain is in hardware-supervised mode.  Meant to be called
 * once at clockdomain layer initialization, since these should remain
 * fixed for a particular architecture.  No return value.
 *
 * XXX autodeps are deprecated and should be removed at the earliest
 * opportunity
 */
static void _autodep_lookup(struct clkdm_autodep *autodep)
{
    struct clockdomain *clkdm;

    if (!autodep)
        return;

    clkdm = clkdm_lookup(autodep->clkdm.name);
    if (!clkdm) {
        pr_err("clockdomain: autodeps: clockdomain %s does not exist\n",
             autodep->clkdm.name);
        clkdm = ERR_PTR(-ENOENT);
    }
    autodep->clkdm.ptr = clkdm;
}

/*
 * _clkdm_add_autodeps - add auto sleepdeps/wkdeps to clkdm upon clock enable
 * @clkdm: struct clockdomain *
 *
 * Add the "autodep" sleep & wakeup dependencies to clockdomain 'clkdm'
 * in hardware-supervised mode.  Meant to be called from clock framework
 * when a clock inside clockdomain 'clkdm' is enabled.  No return value.
 *
 * XXX autodeps are deprecated and should be removed at the earliest
 * opportunity
 */
void _clkdm_add_autodeps(struct clockdomain *clkdm)
{
    struct clkdm_autodep *autodep;

    if (!autodeps || clkdm->flags & CLKDM_NO_AUTODEPS)
        return;

    for (autodep = autodeps; autodep->clkdm.ptr; autodep++) {
        if (IS_ERR(autodep->clkdm.ptr))
            continue;

        pr_debug("clockdomain: %s: adding %s sleepdep/wkdep\n",
             clkdm->name, autodep->clkdm.ptr->name);

        clkdm_add_sleepdep(clkdm, autodep->clkdm.ptr);
        clkdm_add_wkdep(clkdm, autodep->clkdm.ptr);
    }
}

/*
 * _clkdm_add_autodeps - remove auto sleepdeps/wkdeps from clkdm
 * @clkdm: struct clockdomain *
 *
 * Remove the "autodep" sleep & wakeup dependencies from clockdomain 'clkdm'
 * in hardware-supervised mode.  Meant to be called from clock framework
 * when a clock inside clockdomain 'clkdm' is disabled.  No return value.
 *
 * XXX autodeps are deprecated and should be removed at the earliest
 * opportunity
 */
void _clkdm_del_autodeps(struct clockdomain *clkdm)
{
    struct clkdm_autodep *autodep;

    if (!autodeps || clkdm->flags & CLKDM_NO_AUTODEPS)
        return;

    for (autodep = autodeps; autodep->clkdm.ptr; autodep++) {
        if (IS_ERR(autodep->clkdm.ptr))
            continue;

        pr_debug("clockdomain: %s: removing %s sleepdep/wkdep\n",
             clkdm->name, autodep->clkdm.ptr->name);

        clkdm_del_sleepdep(clkdm, autodep->clkdm.ptr);
        clkdm_del_wkdep(clkdm, autodep->clkdm.ptr);
    }
}

static void _resolve_clkdm_deps(struct clockdomain *clkdm,
                struct clkdm_dep *clkdm_deps)
{
    struct clkdm_dep *cd;

    for (cd = clkdm_deps; cd && cd->clkdm_name; cd++) {
        if (cd->clkdm)
            continue;
        cd->clkdm = _clkdm_lookup(cd->clkdm_name);

        WARN(!cd->clkdm, "clockdomain: %s: could not find clkdm %s while resolving dependencies - should never happen",
             clkdm->name, cd->clkdm_name);
    }
}

/* Public functions */

int clkdm_register_platform_funcs(struct clkdm_ops *co)
{
    if (!co)
        return -EINVAL;

    if (arch_clkdm)
        return -EEXIST;

    arch_clkdm = co;

    return 0;
};

int clkdm_register_clkdms(struct clockdomain **cs)
{
    struct clockdomain **c = NULL;

    if (!arch_clkdm)
        return -EACCES;

    if (!cs)
        return -EINVAL;

    for (c = cs; *c; c++)
        _clkdm_register(*c);

    return 0;
}

int clkdm_register_autodeps(struct clkdm_autodep *ia)
{
    struct clkdm_autodep *a = NULL;

    if (list_empty(&clkdm_list))
        return -EACCES;

    if (!ia)
        return -EINVAL;

    if (autodeps)
        return -EEXIST;

    autodeps = ia;
    for (a = autodeps; a->clkdm.ptr; a++)
        _autodep_lookup(a);

    return 0;
}

int clkdm_complete_init(void)
{
    struct clockdomain *clkdm;

    if (list_empty(&clkdm_list))
        return -EACCES;

    list_for_each_entry(clkdm, &clkdm_list, node) {
        if (clkdm->flags & CLKDM_CAN_FORCE_WAKEUP)
            clkdm_wakeup(clkdm);
        else if (clkdm->flags & CLKDM_CAN_DISABLE_AUTO)
            clkdm_deny_idle(clkdm);

        _resolve_clkdm_deps(clkdm, clkdm->wkdep_srcs);
        clkdm_clear_all_wkdeps(clkdm);

        _resolve_clkdm_deps(clkdm, clkdm->sleepdep_srcs);
        clkdm_clear_all_sleepdeps(clkdm);
    }

    return 0;
}

struct clockdomain *clkdm_lookup(const char *name)
{
    struct clockdomain *clkdm, *temp_clkdm;

    if (!name)
        return NULL;

    clkdm = NULL;

    list_for_each_entry(temp_clkdm, &clkdm_list, node) {
        if (!strcmp(name, temp_clkdm->name)) {
            clkdm = temp_clkdm;
            break;
        }
    }

    return clkdm;
}

int clkdm_for_each(int (*fn)(struct clockdomain *clkdm, void *user),
            void *user)
{
    struct clockdomain *clkdm;
    int ret = 0;

    if (!fn)
        return -EINVAL;

    list_for_each_entry(clkdm, &clkdm_list, node) {
        ret = (*fn)(clkdm, user);
        if (ret)
            break;
    }

    return ret;
}


struct powerdomain *clkdm_get_pwrdm(struct clockdomain *clkdm)
{
    if (!clkdm)
        return NULL;

    return clkdm->pwrdm.ptr;
}


/* Hardware clockdomain control */

int clkdm_add_wkdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
{
    struct clkdm_dep *cd;
    int ret = 0;

    if (!clkdm1 || !clkdm2)
        return -EINVAL;

    cd = _clkdm_deps_lookup(clkdm2, clkdm1->wkdep_srcs);
    if (IS_ERR(cd))
        ret = PTR_ERR(cd);

    if (!arch_clkdm || !arch_clkdm->clkdm_add_wkdep)
        ret = -EINVAL;

    if (ret) {
        pr_debug("clockdomain: hardware cannot set/clear wake up of %s when %s wakes up\n",
             clkdm1->name, clkdm2->name);
        return ret;
    }

    if (atomic_inc_return(&cd->wkdep_usecount) == 1) {
        pr_debug("clockdomain: hardware will wake up %s when %s wakes up\n",
             clkdm1->name, clkdm2->name);

        ret = arch_clkdm->clkdm_add_wkdep(clkdm1, clkdm2);
    }

    return ret;
}

int clkdm_del_wkdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
{
    struct clkdm_dep *cd;
    int ret = 0;

    if (!clkdm1 || !clkdm2)
        return -EINVAL;

    cd = _clkdm_deps_lookup(clkdm2, clkdm1->wkdep_srcs);
    if (IS_ERR(cd))
        ret = PTR_ERR(cd);

    if (!arch_clkdm || !arch_clkdm->clkdm_del_wkdep)
        ret = -EINVAL;

    if (ret) {
        pr_debug("clockdomain: hardware cannot set/clear wake up of %s when %s wakes up\n",
             clkdm1->name, clkdm2->name);
        return ret;
    }

    if (atomic_dec_return(&cd->wkdep_usecount) == 0) {
        pr_debug("clockdomain: hardware will no longer wake up %s after %s wakes up\n",
             clkdm1->name, clkdm2->name);

        ret = arch_clkdm->clkdm_del_wkdep(clkdm1, clkdm2);
    }

    return ret;
}

int clkdm_read_wkdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
{
    struct clkdm_dep *cd;
    int ret = 0;

    if (!clkdm1 || !clkdm2)
        return -EINVAL;

    cd = _clkdm_deps_lookup(clkdm2, clkdm1->wkdep_srcs);
    if (IS_ERR(cd))
        ret = PTR_ERR(cd);

    if (!arch_clkdm || !arch_clkdm->clkdm_read_wkdep)
        ret = -EINVAL;

    if (ret) {
        pr_debug("clockdomain: hardware cannot set/clear wake up of %s when %s wakes up\n",
             clkdm1->name, clkdm2->name);
        return ret;
    }

    /* XXX It's faster to return the atomic wkdep_usecount */
    return arch_clkdm->clkdm_read_wkdep(clkdm1, clkdm2);
}

int clkdm_clear_all_wkdeps(struct clockdomain *clkdm)
{
    if (!clkdm)
        return -EINVAL;

    if (!arch_clkdm || !arch_clkdm->clkdm_clear_all_wkdeps)
        return -EINVAL;

    return arch_clkdm->clkdm_clear_all_wkdeps(clkdm);
}

int clkdm_add_sleepdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
{
    struct clkdm_dep *cd;
    int ret = 0;

    if (!clkdm1 || !clkdm2)
        return -EINVAL;

    cd = _clkdm_deps_lookup(clkdm2, clkdm1->sleepdep_srcs);
    if (IS_ERR(cd))
        ret = PTR_ERR(cd);

    if (!arch_clkdm || !arch_clkdm->clkdm_add_sleepdep)
        ret = -EINVAL;

    if (ret) {
        pr_debug("clockdomain: hardware cannot set/clear sleep dependency affecting %s from %s\n",
             clkdm1->name, clkdm2->name);
        return ret;
    }

    if (atomic_inc_return(&cd->sleepdep_usecount) == 1) {
        pr_debug("clockdomain: will prevent %s from sleeping if %s is active\n",
             clkdm1->name, clkdm2->name);

        ret = arch_clkdm->clkdm_add_sleepdep(clkdm1, clkdm2);
    }

    return ret;
}

int clkdm_del_sleepdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
{
    struct clkdm_dep *cd;
    int ret = 0;

    if (!clkdm1 || !clkdm2)
        return -EINVAL;

    cd = _clkdm_deps_lookup(clkdm2, clkdm1->sleepdep_srcs);
    if (IS_ERR(cd))
        ret = PTR_ERR(cd);

    if (!arch_clkdm || !arch_clkdm->clkdm_del_sleepdep)
        ret = -EINVAL;

    if (ret) {
        pr_debug("clockdomain: hardware cannot set/clear sleep dependency affecting %s from %s\n",
             clkdm1->name, clkdm2->name);
        return ret;
    }

    if (atomic_dec_return(&cd->sleepdep_usecount) == 0) {
        pr_debug("clockdomain: will no longer prevent %s from sleeping if %s is active\n",
             clkdm1->name, clkdm2->name);

        ret = arch_clkdm->clkdm_del_sleepdep(clkdm1, clkdm2);
    }

    return ret;
}

int clkdm_read_sleepdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
{
    struct clkdm_dep *cd;
    int ret = 0;

    if (!clkdm1 || !clkdm2)
        return -EINVAL;

    cd = _clkdm_deps_lookup(clkdm2, clkdm1->sleepdep_srcs);
    if (IS_ERR(cd))
        ret = PTR_ERR(cd);

    if (!arch_clkdm || !arch_clkdm->clkdm_read_sleepdep)
        ret = -EINVAL;

    if (ret) {
        pr_debug("clockdomain: hardware cannot set/clear sleep dependency affecting %s from %s\n",
             clkdm1->name, clkdm2->name);
        return ret;
    }

    /* XXX It's faster to return the atomic sleepdep_usecount */
    return arch_clkdm->clkdm_read_sleepdep(clkdm1, clkdm2);
}

int clkdm_clear_all_sleepdeps(struct clockdomain *clkdm)
{
    if (!clkdm)
        return -EINVAL;

    if (!arch_clkdm || !arch_clkdm->clkdm_clear_all_sleepdeps)
        return -EINVAL;

    return arch_clkdm->clkdm_clear_all_sleepdeps(clkdm);
}

int clkdm_sleep(struct clockdomain *clkdm)
{
    int ret;
    unsigned long flags;

    if (!clkdm)
        return -EINVAL;

    if (!(clkdm->flags & CLKDM_CAN_FORCE_SLEEP)) {
        pr_debug("clockdomain: %s does not support forcing sleep via software\n",
             clkdm->name);
        return -EINVAL;
    }

    if (!arch_clkdm || !arch_clkdm->clkdm_sleep)
        return -EINVAL;

    pr_debug("clockdomain: forcing sleep on %s\n", clkdm->name);

    spin_lock_irqsave(&clkdm->lock, flags);
    clkdm->_flags &= ~_CLKDM_FLAG_HWSUP_ENABLED;
    ret = arch_clkdm->clkdm_sleep(clkdm);
    spin_unlock_irqrestore(&clkdm->lock, flags);
    return ret;
}

int clkdm_wakeup(struct clockdomain *clkdm)
{
    int ret;
    unsigned long flags;

    if (!clkdm)
        return -EINVAL;

    if (!(clkdm->flags & CLKDM_CAN_FORCE_WAKEUP)) {
        pr_debug("clockdomain: %s does not support forcing wakeup via software\n",
             clkdm->name);
        return -EINVAL;
    }

    if (!arch_clkdm || !arch_clkdm->clkdm_wakeup)
        return -EINVAL;

    pr_debug("clockdomain: forcing wakeup on %s\n", clkdm->name);

    spin_lock_irqsave(&clkdm->lock, flags);
    clkdm->_flags &= ~_CLKDM_FLAG_HWSUP_ENABLED;
    ret = arch_clkdm->clkdm_wakeup(clkdm);
    ret |= pwrdm_state_switch(clkdm->pwrdm.ptr);
    spin_unlock_irqrestore(&clkdm->lock, flags);
    return ret;
}

void clkdm_allow_idle(struct clockdomain *clkdm)
{
    unsigned long flags;

    if (!clkdm)
        return;

    if (!(clkdm->flags & CLKDM_CAN_ENABLE_AUTO)) {
        pr_debug("clock: %s: automatic idle transitions cannot be enabled\n",
             clkdm->name);
        return;
    }

    if (!arch_clkdm || !arch_clkdm->clkdm_allow_idle)
        return;

    pr_debug("clockdomain: enabling automatic idle transitions for %s\n",
         clkdm->name);

    spin_lock_irqsave(&clkdm->lock, flags);
    clkdm->_flags |= _CLKDM_FLAG_HWSUP_ENABLED;
    arch_clkdm->clkdm_allow_idle(clkdm);
    pwrdm_state_switch(clkdm->pwrdm.ptr);
    spin_unlock_irqrestore(&clkdm->lock, flags);
}

void clkdm_deny_idle(struct clockdomain *clkdm)
{
    unsigned long flags;

    if (!clkdm)
        return;

    if (!(clkdm->flags & CLKDM_CAN_DISABLE_AUTO)) {
        pr_debug("clockdomain: %s: automatic idle transitions cannot be disabled\n",
             clkdm->name);
        return;
    }

    if (!arch_clkdm || !arch_clkdm->clkdm_deny_idle)
        return;

    pr_debug("clockdomain: disabling automatic idle transitions for %s\n",
         clkdm->name);

    spin_lock_irqsave(&clkdm->lock, flags);
    clkdm->_flags &= ~_CLKDM_FLAG_HWSUP_ENABLED;
    arch_clkdm->clkdm_deny_idle(clkdm);
    pwrdm_state_switch(clkdm->pwrdm.ptr);
    spin_unlock_irqrestore(&clkdm->lock, flags);
}

bool clkdm_in_hwsup(struct clockdomain *clkdm)
{
    bool ret;
    unsigned long flags;

    if (!clkdm)
        return false;

    spin_lock_irqsave(&clkdm->lock, flags);
    ret = (clkdm->_flags & _CLKDM_FLAG_HWSUP_ENABLED) ? true : false;
    spin_unlock_irqrestore(&clkdm->lock, flags);

    return ret;
}

bool clkdm_missing_idle_reporting(struct clockdomain *clkdm)
{
    if (!clkdm)
        return false;

    return (clkdm->flags & CLKDM_MISSING_IDLE_REPORTING) ? true : false;
}

/* Clockdomain-to-clock/hwmod framework interface code */

static int _clkdm_clk_hwmod_enable(struct clockdomain *clkdm)
{
    unsigned long flags;

    if (!clkdm || !arch_clkdm || !arch_clkdm->clkdm_clk_enable)
        return -EINVAL;

    spin_lock_irqsave(&clkdm->lock, flags);

    /*
     * For arch's with no autodeps, clkcm_clk_enable
     * should be called for every clock instance or hwmod that is
     * enabled, so the clkdm can be force woken up.
     */
    if ((atomic_inc_return(&clkdm->usecount) > 1) && autodeps) {
        spin_unlock_irqrestore(&clkdm->lock, flags);
        return 0;
    }

    arch_clkdm->clkdm_clk_enable(clkdm);
    pwrdm_state_switch(clkdm->pwrdm.ptr);
    spin_unlock_irqrestore(&clkdm->lock, flags);

    pr_debug("clockdomain: %s: enabled\n", clkdm->name);

    return 0;
}

static int _clkdm_clk_hwmod_disable(struct clockdomain *clkdm)
{
    unsigned long flags;

    if (!clkdm || !arch_clkdm || !arch_clkdm->clkdm_clk_disable)
        return -EINVAL;

    spin_lock_irqsave(&clkdm->lock, flags);

    if (atomic_read(&clkdm->usecount) == 0) {
        spin_unlock_irqrestore(&clkdm->lock, flags);
        WARN_ON(1); /* underflow */
        return -ERANGE;
    }

    if (atomic_dec_return(&clkdm->usecount) > 0) {
        spin_unlock_irqrestore(&clkdm->lock, flags);
        return 0;
    }

    arch_clkdm->clkdm_clk_disable(clkdm);
    pwrdm_state_switch(clkdm->pwrdm.ptr);
    spin_unlock_irqrestore(&clkdm->lock, flags);

    pr_debug("clockdomain: %s: disabled\n", clkdm->name);

    return 0;
}

int clkdm_clk_enable(struct clockdomain *clkdm, struct clk *clk)
{
    /*
     * XXX Rewrite this code to maintain a list of enabled
     * downstream clocks for debugging purposes?
     */

    if (!clk)
        return -EINVAL;

    return _clkdm_clk_hwmod_enable(clkdm);
}

int clkdm_clk_disable(struct clockdomain *clkdm, struct clk *clk)
{
    /*
     * XXX Rewrite this code to maintain a list of enabled
     * downstream clocks for debugging purposes?
     */

    if (!clk)
        return -EINVAL;

    return _clkdm_clk_hwmod_disable(clkdm);
}

int clkdm_hwmod_enable(struct clockdomain *clkdm, struct omap_hwmod *oh)
{
    /* The clkdm attribute does not exist yet prior OMAP4 */
    if (cpu_is_omap24xx() || cpu_is_omap34xx())
        return 0;

    /*
     * XXX Rewrite this code to maintain a list of enabled
     * downstream hwmods for debugging purposes?
     */

    if (!oh)
        return -EINVAL;

    return _clkdm_clk_hwmod_enable(clkdm);
}

int clkdm_hwmod_disable(struct clockdomain *clkdm, struct omap_hwmod *oh)
{
    /* The clkdm attribute does not exist yet prior OMAP4 */
    if (cpu_is_omap24xx() || cpu_is_omap34xx())
        return 0;

    /*
     * XXX Rewrite this code to maintain a list of enabled
     * downstream hwmods for debugging purposes?
     */

    if (!oh)
        return -EINVAL;

    return _clkdm_clk_hwmod_disable(clkdm);
}