Merge remote-tracking branch 'upstream/master' into kvm-devel

[linux-2.6/kvm.git] / arch / arm / mach-omap2 / powerdomain.c

/*
 * OMAP powerdomain control
 *
 * Copyright (C) 2007-2008 Texas Instruments, Inc.
 * Copyright (C) 2007-2011 Nokia Corporation
 *
 * Written by Paul Walmsley
 * Added OMAP4 specific support by Abhijit Pagare <abhijitpagare@ti.com>
 * State counting code by Tero Kristo <tero.kristo@nokia.com>
 *
 * 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/types.h>
#include <linux/list.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <trace/events/power.h>

#include "cm2xxx_3xxx.h"
#include "prcm44xx.h"
#include "cm44xx.h"
#include "prm2xxx_3xxx.h"
#include "prm44xx.h"

#include <asm/cpu.h>
#include <plat/cpu.h>
#include "powerdomain.h"
#include "clockdomain.h"
#include <plat/prcm.h>

#include "pm.h"

#define PWRDM_TRACE_STATES_FLAG (1<<31)

enum {
        PWRDM_STATE_NOW = 0,
        PWRDM_STATE_PREV,
};


/* pwrdm_list contains all registered struct powerdomains */
static LIST_HEAD(pwrdm_list);

static struct pwrdm_ops *arch_pwrdm;

/* Private functions */

static struct powerdomain *_pwrdm_lookup(const char *name)
{
        struct powerdomain *pwrdm, *temp_pwrdm;

        pwrdm = NULL;

        list_for_each_entry(temp_pwrdm, &pwrdm_list, node) {
                if (!strcmp(name, temp_pwrdm->name)) {
                        pwrdm = temp_pwrdm;
                        break;
                }
        }

        return pwrdm;
}

/**
 * _pwrdm_register - register a powerdomain
 * @pwrdm: struct powerdomain * to register
 *
 * Adds a powerdomain to the internal powerdomain list.  Returns
 * -EINVAL if given a null pointer, -EEXIST if a powerdomain is
 * already registered by the provided name, or 0 upon success.
 */
static int _pwrdm_register(struct powerdomain *pwrdm)
{
        int i;

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

        if (!omap_chip_is(pwrdm->omap_chip))
                return -EINVAL;

        if (cpu_is_omap44xx() &&
            pwrdm->prcm_partition == OMAP4430_INVALID_PRCM_PARTITION) {
                pr_err("powerdomain: %s: missing OMAP4 PRCM partition ID\n",
                       pwrdm->name);
                return -EINVAL;
        }

        if (_pwrdm_lookup(pwrdm->name))
                return -EEXIST;

        list_add(&pwrdm->node, &pwrdm_list);

        /* Initialize the powerdomain's state counter */
        for (i = 0; i < PWRDM_MAX_PWRSTS; i++)
                pwrdm->state_counter[i] = 0;

        pwrdm->ret_logic_off_counter = 0;
        for (i = 0; i < pwrdm->banks; i++)
                pwrdm->ret_mem_off_counter[i] = 0;

        pwrdm_wait_transition(pwrdm);
        pwrdm->state = pwrdm_read_pwrst(pwrdm);
        pwrdm->state_counter[pwrdm->state] = 1;

        pr_debug("powerdomain: registered %s\n", pwrdm->name);

        return 0;
}

static void _update_logic_membank_counters(struct powerdomain *pwrdm)
{
        int i;
        u8 prev_logic_pwrst, prev_mem_pwrst;

        prev_logic_pwrst = pwrdm_read_prev_logic_pwrst(pwrdm);
        if ((pwrdm->pwrsts_logic_ret == PWRSTS_OFF_RET) &&
            (prev_logic_pwrst == PWRDM_POWER_OFF))
                pwrdm->ret_logic_off_counter++;

        for (i = 0; i < pwrdm->banks; i++) {
                prev_mem_pwrst = pwrdm_read_prev_mem_pwrst(pwrdm, i);

                if ((pwrdm->pwrsts_mem_ret[i] == PWRSTS_OFF_RET) &&
                    (prev_mem_pwrst == PWRDM_POWER_OFF))
                        pwrdm->ret_mem_off_counter[i]++;
        }
}

static int _pwrdm_state_switch(struct powerdomain *pwrdm, int flag)
{

        int prev, state, trace_state = 0;

        if (pwrdm == NULL)
                return -EINVAL;

        state = pwrdm_read_pwrst(pwrdm);

        switch (flag) {
        case PWRDM_STATE_NOW:
                prev = pwrdm->state;
                break;
        case PWRDM_STATE_PREV:
                prev = pwrdm_read_prev_pwrst(pwrdm);
                if (pwrdm->state != prev)
                        pwrdm->state_counter[prev]++;
                if (prev == PWRDM_POWER_RET)
                        _update_logic_membank_counters(pwrdm);
                /*
                 * If the power domain did not hit the desired state,
                 * generate a trace event with both the desired and hit states
                 */
                if (state != prev) {
                        trace_state = (PWRDM_TRACE_STATES_FLAG |
                                       ((state & OMAP_POWERSTATE_MASK) << 8) |
                                       ((prev & OMAP_POWERSTATE_MASK) << 0));
                        trace_power_domain_target(pwrdm->name, trace_state,
                                                  smp_processor_id());
                }
                break;
        default:
                return -EINVAL;
        }

        if (state != prev)
                pwrdm->state_counter[state]++;

        pm_dbg_update_time(pwrdm, prev);

        pwrdm->state = state;

        return 0;
}

static int _pwrdm_pre_transition_cb(struct powerdomain *pwrdm, void *unused)
{
        pwrdm_clear_all_prev_pwrst(pwrdm);
        _pwrdm_state_switch(pwrdm, PWRDM_STATE_NOW);
        return 0;
}

static int _pwrdm_post_transition_cb(struct powerdomain *pwrdm, void *unused)
{
        _pwrdm_state_switch(pwrdm, PWRDM_STATE_PREV);
        return 0;
}

/* Public functions */

/**
 * pwrdm_init - set up the powerdomain layer
 * @pwrdms: array of struct powerdomain pointers to register
 * @custom_funcs: func pointers for arch specific implementations
 *
 * Loop through the array of powerdomains @pwrdms, registering all
 * that are available on the current CPU.  Also, program all
 * powerdomain target state as ON; this is to prevent domains from
 * hitting low power states (if bootloader has target states set to
 * something other than ON) and potentially even losing context while
 * PM is not fully initialized.  The PM late init code can then program
 * the desired target state for all the power domains.  No return
 * value.
 */
void pwrdm_init(struct powerdomain **pwrdms, struct pwrdm_ops *custom_funcs)
{
        struct powerdomain **p = NULL;
        struct powerdomain *temp_p;

        if (!custom_funcs)
                WARN(1, "powerdomain: No custom pwrdm functions registered\n");
        else
                arch_pwrdm = custom_funcs;

        if (pwrdms) {
                for (p = pwrdms; *p; p++)
                        _pwrdm_register(*p);
        }

        list_for_each_entry(temp_p, &pwrdm_list, node)
                pwrdm_set_next_pwrst(temp_p, PWRDM_POWER_ON);
}

/**
 * pwrdm_lookup - look up a powerdomain by name, return a pointer
 * @name: name of powerdomain
 *
 * Find a registered powerdomain by its name @name.  Returns a pointer
 * to the struct powerdomain if found, or NULL otherwise.
 */
struct powerdomain *pwrdm_lookup(const char *name)
{
        struct powerdomain *pwrdm;

        if (!name)
                return NULL;

        pwrdm = _pwrdm_lookup(name);

        return pwrdm;
}

/**
 * pwrdm_for_each - call function on each registered clockdomain
 * @fn: callback function *
 *
 * Call the supplied function @fn for each registered powerdomain.
 * The callback function @fn can return anything but 0 to bail out
 * early from the iterator.  Returns the last return value of the
 * callback function, which should be 0 for success or anything else
 * to indicate failure; or -EINVAL if the function pointer is null.
 */
int pwrdm_for_each(int (*fn)(struct powerdomain *pwrdm, void *user),
                   void *user)
{
        struct powerdomain *temp_pwrdm;
        int ret = 0;

        if (!fn)
                return -EINVAL;

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

        return ret;
}

/**
 * pwrdm_add_clkdm - add a clockdomain to a powerdomain
 * @pwrdm: struct powerdomain * to add the clockdomain to
 * @clkdm: struct clockdomain * to associate with a powerdomain
 *
 * Associate the clockdomain @clkdm with a powerdomain @pwrdm.  This
 * enables the use of pwrdm_for_each_clkdm().  Returns -EINVAL if
 * presented with invalid pointers; -ENOMEM if memory could not be allocated;
 * or 0 upon success.
 */
int pwrdm_add_clkdm(struct powerdomain *pwrdm, struct clockdomain *clkdm)
{
        int i;
        int ret = -EINVAL;

        if (!pwrdm || !clkdm)
                return -EINVAL;

        pr_debug("powerdomain: associating clockdomain %s with powerdomain "
                 "%s\n", clkdm->name, pwrdm->name);

        for (i = 0; i < PWRDM_MAX_CLKDMS; i++) {
                if (!pwrdm->pwrdm_clkdms[i])
                        break;
#ifdef DEBUG
                if (pwrdm->pwrdm_clkdms[i] == clkdm) {
                        ret = -EINVAL;
                        goto pac_exit;
                }
#endif
        }

        if (i == PWRDM_MAX_CLKDMS) {
                pr_debug("powerdomain: increase PWRDM_MAX_CLKDMS for "
                         "pwrdm %s clkdm %s\n", pwrdm->name, clkdm->name);
                WARN_ON(1);
                ret = -ENOMEM;
                goto pac_exit;
        }

        pwrdm->pwrdm_clkdms[i] = clkdm;

        ret = 0;

pac_exit:
        return ret;
}

/**
 * pwrdm_del_clkdm - remove a clockdomain from a powerdomain
 * @pwrdm: struct powerdomain * to add the clockdomain to
 * @clkdm: struct clockdomain * to associate with a powerdomain
 *
 * Dissociate the clockdomain @clkdm from the powerdomain
 * @pwrdm. Returns -EINVAL if presented with invalid pointers; -ENOENT
 * if @clkdm was not associated with the powerdomain, or 0 upon
 * success.
 */
int pwrdm_del_clkdm(struct powerdomain *pwrdm, struct clockdomain *clkdm)
{
        int ret = -EINVAL;
        int i;

        if (!pwrdm || !clkdm)
                return -EINVAL;

        pr_debug("powerdomain: dissociating clockdomain %s from powerdomain "
                 "%s\n", clkdm->name, pwrdm->name);

        for (i = 0; i < PWRDM_MAX_CLKDMS; i++)
                if (pwrdm->pwrdm_clkdms[i] == clkdm)
                        break;

        if (i == PWRDM_MAX_CLKDMS) {
                pr_debug("powerdomain: clkdm %s not associated with pwrdm "
                         "%s ?!\n", clkdm->name, pwrdm->name);
                ret = -ENOENT;
                goto pdc_exit;
        }

        pwrdm->pwrdm_clkdms[i] = NULL;

        ret = 0;

pdc_exit:
        return ret;
}

/**
 * pwrdm_for_each_clkdm - call function on each clkdm in a pwrdm
 * @pwrdm: struct powerdomain * to iterate over
 * @fn: callback function *
 *
 * Call the supplied function @fn for each clockdomain in the powerdomain
 * @pwrdm.  The callback function can return anything but 0 to bail
 * out early from the iterator.  Returns -EINVAL if presented with
 * invalid pointers; or passes along the last return value of the
 * callback function, which should be 0 for success or anything else
 * to indicate failure.
 */
int pwrdm_for_each_clkdm(struct powerdomain *pwrdm,
                         int (*fn)(struct powerdomain *pwrdm,
                                   struct clockdomain *clkdm))
{
        int ret = 0;
        int i;

        if (!fn)
                return -EINVAL;

        for (i = 0; i < PWRDM_MAX_CLKDMS && !ret; i++)
                ret = (*fn)(pwrdm, pwrdm->pwrdm_clkdms[i]);

        return ret;
}

/**
 * pwrdm_get_mem_bank_count - get number of memory banks in this powerdomain
 * @pwrdm: struct powerdomain *
 *
 * Return the number of controllable memory banks in powerdomain @pwrdm,
 * starting with 1.  Returns -EINVAL if the powerdomain pointer is null.
 */
int pwrdm_get_mem_bank_count(struct powerdomain *pwrdm)
{
        if (!pwrdm)
                return -EINVAL;

        return pwrdm->banks;
}

/**
 * pwrdm_set_next_pwrst - set next powerdomain power state
 * @pwrdm: struct powerdomain * to set
 * @pwrst: one of the PWRDM_POWER_* macros
 *
 * Set the powerdomain @pwrdm's next power state to @pwrst.  The powerdomain
 * may not enter this state immediately if the preconditions for this state
 * have not been satisfied.  Returns -EINVAL if the powerdomain pointer is
 * null or if the power state is invalid for the powerdomin, or returns 0
 * upon success.
 */
int pwrdm_set_next_pwrst(struct powerdomain *pwrdm, u8 pwrst)
{
        int ret = -EINVAL;

        if (!pwrdm)
                return -EINVAL;

        if (!(pwrdm->pwrsts & (1 << pwrst)))
                return -EINVAL;

        pr_debug("powerdomain: setting next powerstate for %s to %0x\n",
                 pwrdm->name, pwrst);

        if (arch_pwrdm && arch_pwrdm->pwrdm_set_next_pwrst) {
                /* Trace the pwrdm desired target state */
                trace_power_domain_target(pwrdm->name, pwrst,
                                          smp_processor_id());
                /* Program the pwrdm desired target state */
                ret = arch_pwrdm->pwrdm_set_next_pwrst(pwrdm, pwrst);
        }

        return ret;
}

/**
 * pwrdm_read_next_pwrst - get next powerdomain power state
 * @pwrdm: struct powerdomain * to get power state
 *
 * Return the powerdomain @pwrdm's next power state.  Returns -EINVAL
 * if the powerdomain pointer is null or returns the next power state
 * upon success.
 */
int pwrdm_read_next_pwrst(struct powerdomain *pwrdm)
{
        int ret = -EINVAL;

        if (!pwrdm)
                return -EINVAL;

        if (arch_pwrdm && arch_pwrdm->pwrdm_read_next_pwrst)
                ret = arch_pwrdm->pwrdm_read_next_pwrst(pwrdm);

        return ret;
}

/**
 * pwrdm_read_pwrst - get current powerdomain power state
 * @pwrdm: struct powerdomain * to get power state
 *
 * Return the powerdomain @pwrdm's current power state. Returns -EINVAL
 * if the powerdomain pointer is null or returns the current power state
 * upon success.
 */
int pwrdm_read_pwrst(struct powerdomain *pwrdm)
{
        int ret = -EINVAL;

        if (!pwrdm)
                return -EINVAL;

        if (arch_pwrdm && arch_pwrdm->pwrdm_read_pwrst)
                ret = arch_pwrdm->pwrdm_read_pwrst(pwrdm);

        return ret;
}

/**
 * pwrdm_read_prev_pwrst - get previous powerdomain power state
 * @pwrdm: struct powerdomain * to get previous power state
 *
 * Return the powerdomain @pwrdm's previous power state.  Returns -EINVAL
 * if the powerdomain pointer is null or returns the previous power state
 * upon success.
 */
int pwrdm_read_prev_pwrst(struct powerdomain *pwrdm)
{
        int ret = -EINVAL;

        if (!pwrdm)
                return -EINVAL;

        if (arch_pwrdm && arch_pwrdm->pwrdm_read_prev_pwrst)
                ret = arch_pwrdm->pwrdm_read_prev_pwrst(pwrdm);

        return ret;
}

/**
 * pwrdm_set_logic_retst - set powerdomain logic power state upon retention
 * @pwrdm: struct powerdomain * to set
 * @pwrst: one of the PWRDM_POWER_* macros
 *
 * Set the next power state @pwrst that the logic portion of the
 * powerdomain @pwrdm will enter when the powerdomain enters retention.
 * This will be either RETENTION or OFF, if supported.  Returns
 * -EINVAL if the powerdomain pointer is null or the target power
 * state is not not supported, or returns 0 upon success.
 */
int pwrdm_set_logic_retst(struct powerdomain *pwrdm, u8 pwrst)
{
        int ret = -EINVAL;

        if (!pwrdm)
                return -EINVAL;

        if (!(pwrdm->pwrsts_logic_ret & (1 << pwrst)))
                return -EINVAL;

        pr_debug("powerdomain: setting next logic powerstate for %s to %0x\n",
                 pwrdm->name, pwrst);

        if (arch_pwrdm && arch_pwrdm->pwrdm_set_logic_retst)
                ret = arch_pwrdm->pwrdm_set_logic_retst(pwrdm, pwrst);

        return ret;
}

/**
 * pwrdm_set_mem_onst - set memory power state while powerdomain ON
 * @pwrdm: struct powerdomain * to set
 * @bank: memory bank number to set (0-3)
 * @pwrst: one of the PWRDM_POWER_* macros
 *
 * Set the next power state @pwrst that memory bank @bank of the
 * powerdomain @pwrdm will enter when the powerdomain enters the ON
 * state.  @bank will be a number from 0 to 3, and represents different
 * types of memory, depending on the powerdomain.  Returns -EINVAL if
 * the powerdomain pointer is null or the target power state is not
 * not supported for this memory bank, -EEXIST if the target memory
 * bank does not exist or is not controllable, or returns 0 upon
 * success.
 */
int pwrdm_set_mem_onst(struct powerdomain *pwrdm, u8 bank, u8 pwrst)
{
        int ret = -EINVAL;

        if (!pwrdm)
                return -EINVAL;

        if (pwrdm->banks < (bank + 1))
                return -EEXIST;

        if (!(pwrdm->pwrsts_mem_on[bank] & (1 << pwrst)))
                return -EINVAL;

        pr_debug("powerdomain: setting next memory powerstate for domain %s "
                 "bank %0x while pwrdm-ON to %0x\n", pwrdm->name, bank, pwrst);

        if (arch_pwrdm && arch_pwrdm->pwrdm_set_mem_onst)
                ret = arch_pwrdm->pwrdm_set_mem_onst(pwrdm, bank, pwrst);

        return ret;
}

/**
 * pwrdm_set_mem_retst - set memory power state while powerdomain in RET
 * @pwrdm: struct powerdomain * to set
 * @bank: memory bank number to set (0-3)
 * @pwrst: one of the PWRDM_POWER_* macros
 *
 * Set the next power state @pwrst that memory bank @bank of the
 * powerdomain @pwrdm will enter when the powerdomain enters the
 * RETENTION state.  Bank will be a number from 0 to 3, and represents
 * different types of memory, depending on the powerdomain.  @pwrst
 * will be either RETENTION or OFF, if supported.  Returns -EINVAL if
 * the powerdomain pointer is null or the target power state is not
 * not supported for this memory bank, -EEXIST if the target memory
 * bank does not exist or is not controllable, or returns 0 upon
 * success.
 */
int pwrdm_set_mem_retst(struct powerdomain *pwrdm, u8 bank, u8 pwrst)
{
        int ret = -EINVAL;

        if (!pwrdm)
                return -EINVAL;

        if (pwrdm->banks < (bank + 1))
                return -EEXIST;

        if (!(pwrdm->pwrsts_mem_ret[bank] & (1 << pwrst)))
                return -EINVAL;

        pr_debug("powerdomain: setting next memory powerstate for domain %s "
                 "bank %0x while pwrdm-RET to %0x\n", pwrdm->name, bank, pwrst);

        if (arch_pwrdm && arch_pwrdm->pwrdm_set_mem_retst)
                ret = arch_pwrdm->pwrdm_set_mem_retst(pwrdm, bank, pwrst);

        return ret;
}

/**
 * pwrdm_read_logic_pwrst - get current powerdomain logic retention power state
 * @pwrdm: struct powerdomain * to get current logic retention power state
 *
 * Return the power state that the logic portion of powerdomain @pwrdm
 * will enter when the powerdomain enters retention.  Returns -EINVAL
 * if the powerdomain pointer is null or returns the logic retention
 * power state upon success.
 */
int pwrdm_read_logic_pwrst(struct powerdomain *pwrdm)
{
        int ret = -EINVAL;

        if (!pwrdm)
                return -EINVAL;

        if (arch_pwrdm && arch_pwrdm->pwrdm_read_logic_pwrst)
                ret = arch_pwrdm->pwrdm_read_logic_pwrst(pwrdm);

        return ret;
}

/**
 * pwrdm_read_prev_logic_pwrst - get previous powerdomain logic power state
 * @pwrdm: struct powerdomain * to get previous logic power state
 *
 * Return the powerdomain @pwrdm's previous logic power state.  Returns
 * -EINVAL if the powerdomain pointer is null or returns the previous
 * logic power state upon success.
 */
int pwrdm_read_prev_logic_pwrst(struct powerdomain *pwrdm)
{
        int ret = -EINVAL;

        if (!pwrdm)
                return -EINVAL;

        if (arch_pwrdm && arch_pwrdm->pwrdm_read_prev_logic_pwrst)
                ret = arch_pwrdm->pwrdm_read_prev_logic_pwrst(pwrdm);

        return ret;
}

/**
 * pwrdm_read_logic_retst - get next powerdomain logic power state
 * @pwrdm: struct powerdomain * to get next logic power state
 *
 * Return the powerdomain pwrdm's logic power state.  Returns -EINVAL
 * if the powerdomain pointer is null or returns the next logic
 * power state upon success.
 */
int pwrdm_read_logic_retst(struct powerdomain *pwrdm)
{
        int ret = -EINVAL;

        if (!pwrdm)
                return -EINVAL;

        if (arch_pwrdm && arch_pwrdm->pwrdm_read_logic_retst)
                ret = arch_pwrdm->pwrdm_read_logic_retst(pwrdm);

        return ret;
}

/**
 * pwrdm_read_mem_pwrst - get current memory bank power state
 * @pwrdm: struct powerdomain * to get current memory bank power state
 * @bank: memory bank number (0-3)
 *
 * Return the powerdomain @pwrdm's current memory power state for bank
 * @bank.  Returns -EINVAL if the powerdomain pointer is null, -EEXIST if
 * the target memory bank does not exist or is not controllable, or
 * returns the current memory power state upon success.
 */
int pwrdm_read_mem_pwrst(struct powerdomain *pwrdm, u8 bank)
{
        int ret = -EINVAL;

        if (!pwrdm)
                return ret;

        if (pwrdm->banks < (bank + 1))
                return ret;

        if (pwrdm->flags & PWRDM_HAS_MPU_QUIRK)
                bank = 1;

        if (arch_pwrdm && arch_pwrdm->pwrdm_read_mem_pwrst)
                ret = arch_pwrdm->pwrdm_read_mem_pwrst(pwrdm, bank);

        return ret;
}

/**
 * pwrdm_read_prev_mem_pwrst - get previous memory bank power state
 * @pwrdm: struct powerdomain * to get previous memory bank power state
 * @bank: memory bank number (0-3)
 *
 * Return the powerdomain @pwrdm's previous memory power state for
 * bank @bank.  Returns -EINVAL if the powerdomain pointer is null,
 * -EEXIST if the target memory bank does not exist or is not
 * controllable, or returns the previous memory power state upon
 * success.
 */
int pwrdm_read_prev_mem_pwrst(struct powerdomain *pwrdm, u8 bank)
{
        int ret = -EINVAL;

        if (!pwrdm)
                return ret;

        if (pwrdm->banks < (bank + 1))
                return ret;

        if (pwrdm->flags & PWRDM_HAS_MPU_QUIRK)
                bank = 1;

        if (arch_pwrdm && arch_pwrdm->pwrdm_read_prev_mem_pwrst)
                ret = arch_pwrdm->pwrdm_read_prev_mem_pwrst(pwrdm, bank);

        return ret;
}

/**
 * pwrdm_read_mem_retst - get next memory bank power state
 * @pwrdm: struct powerdomain * to get mext memory bank power state
 * @bank: memory bank number (0-3)
 *
 * Return the powerdomain pwrdm's next memory power state for bank
 * x.  Returns -EINVAL if the powerdomain pointer is null, -EEXIST if
 * the target memory bank does not exist or is not controllable, or
 * returns the next memory power state upon success.
 */
int pwrdm_read_mem_retst(struct powerdomain *pwrdm, u8 bank)
{
        int ret = -EINVAL;

        if (!pwrdm)
                return ret;

        if (pwrdm->banks < (bank + 1))
                return ret;

        if (arch_pwrdm && arch_pwrdm->pwrdm_read_mem_retst)
                ret = arch_pwrdm->pwrdm_read_mem_retst(pwrdm, bank);

        return ret;
}

/**
 * pwrdm_clear_all_prev_pwrst - clear previous powerstate register for a pwrdm
 * @pwrdm: struct powerdomain * to clear
 *
 * Clear the powerdomain's previous power state register @pwrdm.
 * Clears the entire register, including logic and memory bank
 * previous power states.  Returns -EINVAL if the powerdomain pointer
 * is null, or returns 0 upon success.
 */
int pwrdm_clear_all_prev_pwrst(struct powerdomain *pwrdm)
{
        int ret = -EINVAL;

        if (!pwrdm)
                return ret;

        /*
         * XXX should get the powerdomain's current state here;
         * warn & fail if it is not ON.
         */

        pr_debug("powerdomain: clearing previous power state reg for %s\n",
                 pwrdm->name);

        if (arch_pwrdm && arch_pwrdm->pwrdm_clear_all_prev_pwrst)
                ret = arch_pwrdm->pwrdm_clear_all_prev_pwrst(pwrdm);

        return ret;
}

/**
 * pwrdm_enable_hdwr_sar - enable automatic hardware SAR for a pwrdm
 * @pwrdm: struct powerdomain *
 *
 * Enable automatic context save-and-restore upon power state change
 * for some devices in the powerdomain @pwrdm.  Warning: this only
 * affects a subset of devices in a powerdomain; check the TRM
 * closely.  Returns -EINVAL if the powerdomain pointer is null or if
 * the powerdomain does not support automatic save-and-restore, or
 * returns 0 upon success.
 */
int pwrdm_enable_hdwr_sar(struct powerdomain *pwrdm)
{
        int ret = -EINVAL;

        if (!pwrdm)
                return ret;

        if (!(pwrdm->flags & PWRDM_HAS_HDWR_SAR))
                return ret;

        pr_debug("powerdomain: %s: setting SAVEANDRESTORE bit\n",
                 pwrdm->name);

        if (arch_pwrdm && arch_pwrdm->pwrdm_enable_hdwr_sar)
                ret = arch_pwrdm->pwrdm_enable_hdwr_sar(pwrdm);

        return ret;
}

/**
 * pwrdm_disable_hdwr_sar - disable automatic hardware SAR for a pwrdm
 * @pwrdm: struct powerdomain *
 *
 * Disable automatic context save-and-restore upon power state change
 * for some devices in the powerdomain @pwrdm.  Warning: this only
 * affects a subset of devices in a powerdomain; check the TRM
 * closely.  Returns -EINVAL if the powerdomain pointer is null or if
 * the powerdomain does not support automatic save-and-restore, or
 * returns 0 upon success.
 */
int pwrdm_disable_hdwr_sar(struct powerdomain *pwrdm)
{
        int ret = -EINVAL;

        if (!pwrdm)
                return ret;

        if (!(pwrdm->flags & PWRDM_HAS_HDWR_SAR))
                return ret;

        pr_debug("powerdomain: %s: clearing SAVEANDRESTORE bit\n",
                 pwrdm->name);

        if (arch_pwrdm && arch_pwrdm->pwrdm_disable_hdwr_sar)
                ret = arch_pwrdm->pwrdm_disable_hdwr_sar(pwrdm);

        return ret;
}

/**
 * pwrdm_has_hdwr_sar - test whether powerdomain supports hardware SAR
 * @pwrdm: struct powerdomain *
 *
 * Returns 1 if powerdomain @pwrdm supports hardware save-and-restore
 * for some devices, or 0 if it does not.
 */
bool pwrdm_has_hdwr_sar(struct powerdomain *pwrdm)
{
        return (pwrdm && pwrdm->flags & PWRDM_HAS_HDWR_SAR) ? 1 : 0;
}

/**
 * pwrdm_set_lowpwrstchange - Request a low power state change
 * @pwrdm: struct powerdomain *
 *
 * Allows a powerdomain to transtion to a lower power sleep state
 * from an existing sleep state without waking up the powerdomain.
 * Returns -EINVAL if the powerdomain pointer is null or if the
 * powerdomain does not support LOWPOWERSTATECHANGE, or returns 0
 * upon success.
 */
int pwrdm_set_lowpwrstchange(struct powerdomain *pwrdm)
{
        int ret = -EINVAL;

        if (!pwrdm)
                return -EINVAL;

        if (!(pwrdm->flags & PWRDM_HAS_LOWPOWERSTATECHANGE))
                return -EINVAL;

        pr_debug("powerdomain: %s: setting LOWPOWERSTATECHANGE bit\n",
                 pwrdm->name);

        if (arch_pwrdm && arch_pwrdm->pwrdm_set_lowpwrstchange)
                ret = arch_pwrdm->pwrdm_set_lowpwrstchange(pwrdm);

        return ret;
}

/**
 * pwrdm_wait_transition - wait for powerdomain power transition to finish
 * @pwrdm: struct powerdomain * to wait for
 *
 * If the powerdomain @pwrdm is in the process of a state transition,
 * spin until it completes the power transition, or until an iteration
 * bailout value is reached. Returns -EINVAL if the powerdomain
 * pointer is null, -EAGAIN if the bailout value was reached, or
 * returns 0 upon success.
 */
int pwrdm_wait_transition(struct powerdomain *pwrdm)
{
        int ret = -EINVAL;

        if (!pwrdm)
                return -EINVAL;

        if (arch_pwrdm && arch_pwrdm->pwrdm_wait_transition)
                ret = arch_pwrdm->pwrdm_wait_transition(pwrdm);

        return ret;
}

int pwrdm_state_switch(struct powerdomain *pwrdm)
{
        return _pwrdm_state_switch(pwrdm, PWRDM_STATE_NOW);
}

int pwrdm_clkdm_state_switch(struct clockdomain *clkdm)
{
        if (clkdm != NULL && clkdm->pwrdm.ptr != NULL) {
                pwrdm_wait_transition(clkdm->pwrdm.ptr);
                return pwrdm_state_switch(clkdm->pwrdm.ptr);
        }

        return -EINVAL;
}

int pwrdm_pre_transition(void)
{
        pwrdm_for_each(_pwrdm_pre_transition_cb, NULL);
        return 0;
}

int pwrdm_post_transition(void)
{
        pwrdm_for_each(_pwrdm_post_transition_cb, NULL);
        return 0;
}

/**
 * pwrdm_get_context_loss_count - get powerdomain's context loss count
 * @pwrdm: struct powerdomain * to wait for
 *
 * Context loss count is the sum of powerdomain off-mode counter, the
 * logic off counter and the per-bank memory off counter.  Returns 0
 * (and WARNs) upon error, otherwise, returns the context loss count.
 */
u32 pwrdm_get_context_loss_count(struct powerdomain *pwrdm)
{
        int i, count;

        if (!pwrdm) {
                WARN(1, "powerdomain: %s: pwrdm is null\n", __func__);
                return 0;
        }

        count = pwrdm->state_counter[PWRDM_POWER_OFF];
        count += pwrdm->ret_logic_off_counter;

        for (i = 0; i < pwrdm->banks; i++)
                count += pwrdm->ret_mem_off_counter[i];

        pr_debug("powerdomain: %s: context loss count = %u\n",
                 pwrdm->name, count);

        return count;
}

/**
 * pwrdm_can_ever_lose_context - can this powerdomain ever lose context?
 * @pwrdm: struct powerdomain *
 *
 * Given a struct powerdomain * @pwrdm, returns 1 if the powerdomain
 * can lose either memory or logic context or if @pwrdm is invalid, or
 * returns 0 otherwise.  This function is not concerned with how the
 * powerdomain registers are programmed (i.e., to go off or not); it's
 * concerned with whether it's ever possible for this powerdomain to
 * go off while some other part of the chip is active.  This function
 * assumes that every powerdomain can go to either ON or INACTIVE.
 */
bool pwrdm_can_ever_lose_context(struct powerdomain *pwrdm)
{
        int i;

        if (IS_ERR_OR_NULL(pwrdm)) {
                pr_debug("powerdomain: %s: invalid powerdomain pointer\n",
                         __func__);
                return 1;
        }

        if (pwrdm->pwrsts & PWRSTS_OFF)
                return 1;

        if (pwrdm->pwrsts & PWRSTS_RET) {
                if (pwrdm->pwrsts_logic_ret & PWRSTS_OFF)
                        return 1;

                for (i = 0; i < pwrdm->banks; i++)
                        if (pwrdm->pwrsts_mem_ret[i] & PWRSTS_OFF)
                                return 1;
        }

        for (i = 0; i < pwrdm->banks; i++)
                if (pwrdm->pwrsts_mem_on[i] & PWRSTS_OFF)
                        return 1;

        return 0;
}