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clock.c

/* linux/arch/arm/plat-s3c24xx/clock.c
 *
 * Copyright 2004-2005 Simtec Electronics
 *    Ben Dooks <ben@simtec.co.uk>
 *
 * S3C24XX Core clock control support
 *
 * Based on, and code from linux/arch/arm/mach-versatile/clock.c
 **
 **  Copyright (C) 2004 ARM Limited.
 **  Written by Deep Blue Solutions Limited.
 *
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/sysdev.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/clk.h>
#include <linux/spinlock.h>
#include <linux/io.h>
#if defined(CONFIG_DEBUG_FS)
#include <linux/debugfs.h>
#endif

#include <mach/hardware.h>
#include <asm/irq.h>

#include <plat/cpu-freq.h>

#include <plat/clock.h>
#include <plat/cpu.h>

#include <linux/serial_core.h>
#include <plat/regs-serial.h> /* for s3c24xx_uart_devs */

/* clock information */

static LIST_HEAD(clocks);

/* We originally used an mutex here, but some contexts (see resume)
 * are calling functions such as clk_set_parent() with IRQs disabled
 * causing an BUG to be triggered.
 */
DEFINE_SPINLOCK(clocks_lock);

/* enable and disable calls for use with the clk struct */

static int clk_null_enable(struct clk *clk, int enable)
{
      return 0;
}

static int dev_is_s3c_uart(struct device *dev)
{
      struct platform_device **pdev = s3c24xx_uart_devs;
      int i;
      for (i = 0; i < ARRAY_SIZE(s3c24xx_uart_devs); i++, pdev++)
            if (*pdev && dev == &(*pdev)->dev)
                  return 1;
      return 0;
}

/*
 * Serial drivers call get_clock() very early, before platform bus
 * has been set up, this requires a special check to let them get
 * a proper clock
 */

static int dev_is_platform_device(struct device *dev)
{
      return dev->bus == &platform_bus_type ||
             (dev->bus == NULL && dev_is_s3c_uart(dev));
}

/* Clock API calls */

struct clk *clk_get(struct device *dev, const char *id)
{
      struct clk *p;
      struct clk *clk = ERR_PTR(-ENOENT);
      int idno;

      if (dev == NULL || !dev_is_platform_device(dev))
            idno = -1;
      else
            idno = to_platform_device(dev)->id;

      spin_lock(&clocks_lock);

      list_for_each_entry(p, &clocks, list) {
            if (p->id == idno &&
                strcmp(id, p->name) == 0 &&
                try_module_get(p->owner)) {
                  clk = p;
                  break;
            }
      }

      /* check for the case where a device was supplied, but the
       * clock that was being searched for is not device specific */

      if (IS_ERR(clk)) {
            list_for_each_entry(p, &clocks, list) {
                  if (p->id == -1 && strcmp(id, p->name) == 0 &&
                      try_module_get(p->owner)) {
                        clk = p;
                        break;
                  }
            }
      }

      spin_unlock(&clocks_lock);
      return clk;
}

void clk_put(struct clk *clk)
{
      module_put(clk->owner);
}

int clk_enable(struct clk *clk)
{
      if (IS_ERR(clk) || clk == NULL)
            return -EINVAL;

      clk_enable(clk->parent);

      spin_lock(&clocks_lock);

      if ((clk->usage++) == 0)
            (clk->enable)(clk, 1);

      spin_unlock(&clocks_lock);
      return 0;
}

void clk_disable(struct clk *clk)
{
      if (IS_ERR(clk) || clk == NULL)
            return;

      spin_lock(&clocks_lock);

      if ((--clk->usage) == 0)
            (clk->enable)(clk, 0);

      spin_unlock(&clocks_lock);
      clk_disable(clk->parent);
}


unsigned long clk_get_rate(struct clk *clk)
{
      if (IS_ERR(clk))
            return 0;

      if (clk->rate != 0)
            return clk->rate;

      if (clk->ops != NULL && clk->ops->get_rate != NULL)
            return (clk->ops->get_rate)(clk);

      if (clk->parent != NULL)
            return clk_get_rate(clk->parent);

      return clk->rate;
}

long clk_round_rate(struct clk *clk, unsigned long rate)
{
      if (!IS_ERR(clk) && clk->ops && clk->ops->round_rate)
            return (clk->ops->round_rate)(clk, rate);

      return rate;
}

int clk_set_rate(struct clk *clk, unsigned long rate)
{
      int ret;

      if (IS_ERR(clk))
            return -EINVAL;

      /* We do not default just do a clk->rate = rate as
       * the clock may have been made this way by choice.
       */

      WARN_ON(clk->ops == NULL);
      WARN_ON(clk->ops && clk->ops->set_rate == NULL);

      if (clk->ops == NULL || clk->ops->set_rate == NULL)
            return -EINVAL;

      spin_lock(&clocks_lock);
      ret = (clk->ops->set_rate)(clk, rate);
      spin_unlock(&clocks_lock);

      return ret;
}

struct clk *clk_get_parent(struct clk *clk)
{
      return clk->parent;
}

int clk_set_parent(struct clk *clk, struct clk *parent)
{
      int ret = 0;

      if (IS_ERR(clk))
            return -EINVAL;

      spin_lock(&clocks_lock);

      if (clk->ops && clk->ops->set_parent)
            ret = (clk->ops->set_parent)(clk, parent);

      spin_unlock(&clocks_lock);

      return ret;
}

EXPORT_SYMBOL(clk_get);
EXPORT_SYMBOL(clk_put);
EXPORT_SYMBOL(clk_enable);
EXPORT_SYMBOL(clk_disable);
EXPORT_SYMBOL(clk_get_rate);
EXPORT_SYMBOL(clk_round_rate);
EXPORT_SYMBOL(clk_set_rate);
EXPORT_SYMBOL(clk_get_parent);
EXPORT_SYMBOL(clk_set_parent);

/* base clocks */

int clk_default_setrate(struct clk *clk, unsigned long rate)
{
      clk->rate = rate;
      return 0;
}

struct clk_ops clk_ops_def_setrate = {
      .set_rate   = clk_default_setrate,
};

struct clk clk_xtal = {
      .name       = "xtal",
      .id         = -1,
      .rate       = 0,
      .parent           = NULL,
      .ctrlbit    = 0,
};

struct clk clk_ext = {
      .name       = "ext",
      .id         = -1,
};

struct clk clk_epll = {
      .name       = "epll",
      .id         = -1,
};

struct clk clk_mpll = {
      .name       = "mpll",
      .id         = -1,
      .ops        = &clk_ops_def_setrate,
};

struct clk clk_upll = {
      .name       = "upll",
      .id         = -1,
      .parent           = NULL,
      .ctrlbit    = 0,
};

struct clk clk_f = {
      .name       = "fclk",
      .id         = -1,
      .rate       = 0,
      .parent           = &clk_mpll,
      .ctrlbit    = 0,
};

struct clk clk_h = {
      .name       = "hclk",
      .id         = -1,
      .rate       = 0,
      .parent           = NULL,
      .ctrlbit    = 0,
      .ops        = &clk_ops_def_setrate,
};

struct clk clk_p = {
      .name       = "pclk",
      .id         = -1,
      .rate       = 0,
      .parent           = NULL,
      .ctrlbit    = 0,
      .ops        = &clk_ops_def_setrate,
};

struct clk clk_usb_bus = {
      .name       = "usb-bus",
      .id         = -1,
      .rate       = 0,
      .parent           = &clk_upll,
};


struct clk s3c24xx_uclk = {
      .name       = "uclk",
      .id         = -1,
};

/* initialise the clock system */

/**
 * s3c24xx_register_clock() - register a clock
 * @clk: The clock to register
 *
 * Add the specified clock to the list of clocks known by the system.
 */
int s3c24xx_register_clock(struct clk *clk)
{
      if (clk->enable == NULL)
            clk->enable = clk_null_enable;

      /* add to the list of available clocks */

      /* Quick check to see if this clock has already been registered. */
      BUG_ON(clk->list.prev != clk->list.next);

      spin_lock(&clocks_lock);
      list_add(&clk->list, &clocks);
      spin_unlock(&clocks_lock);

      return 0;
}

/**
 * s3c24xx_register_clocks() - register an array of clock pointers
 * @clks: Pointer to an array of struct clk pointers
 * @nr_clks: The number of clocks in the @clks array.
 *
 * Call s3c24xx_register_clock() for all the clock pointers contained
 * in the @clks list. Returns the number of failures.
 */
int s3c24xx_register_clocks(struct clk **clks, int nr_clks)
{
      int fails = 0;

      for (; nr_clks > 0; nr_clks--, clks++) {
            if (s3c24xx_register_clock(*clks) < 0) {
                  struct clk *clk = *clks;
                  printk(KERN_ERR "%s: failed to register %p: %s\n",
                         __func__, clk, clk->name);
                  fails++;
            }
      }

      return fails;
}

/**
 * s3c_register_clocks() - register an array of clocks
 * @clkp: Pointer to the first clock in the array.
 * @nr_clks: Number of clocks to register.
 *
 * Call s3c24xx_register_clock() on the @clkp array given, printing an
 * error if it fails to register the clock (unlikely).
 */
void __init s3c_register_clocks(struct clk *clkp, int nr_clks)
{
      int ret;

      for (; nr_clks > 0; nr_clks--, clkp++) {
            ret = s3c24xx_register_clock(clkp);

            if (ret < 0) {
                  printk(KERN_ERR "Failed to register clock %s (%d)\n",
                         clkp->name, ret);
            }
      }
}

/**
 * s3c_disable_clocks() - disable an array of clocks
 * @clkp: Pointer to the first clock in the array.
 * @nr_clks: Number of clocks to register.
 *
 * for internal use only at initialisation time. disable the clocks in the
 * @clkp array.
 */

void __init s3c_disable_clocks(struct clk *clkp, int nr_clks)
{
      for (; nr_clks > 0; nr_clks--, clkp++)
            (clkp->enable)(clkp, 0);
}

/* initialise all the clocks */

int __init s3c24xx_register_baseclocks(unsigned long xtal)
{
      printk(KERN_INFO "S3C24XX Clocks, Copyright 2004 Simtec Electronics\n");

      clk_xtal.rate = xtal;

      /* register our clocks */

      if (s3c24xx_register_clock(&clk_xtal) < 0)
            printk(KERN_ERR "failed to register master xtal\n");

      if (s3c24xx_register_clock(&clk_mpll) < 0)
            printk(KERN_ERR "failed to register mpll clock\n");

      if (s3c24xx_register_clock(&clk_upll) < 0)
            printk(KERN_ERR "failed to register upll clock\n");

      if (s3c24xx_register_clock(&clk_f) < 0)
            printk(KERN_ERR "failed to register cpu fclk\n");

      if (s3c24xx_register_clock(&clk_h) < 0)
            printk(KERN_ERR "failed to register cpu hclk\n");

      if (s3c24xx_register_clock(&clk_p) < 0)
            printk(KERN_ERR "failed to register cpu pclk\n");

      return 0;
}

#if defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS)
/* debugfs support to trace clock tree hierarchy and attributes */

static struct dentry *clk_debugfs_root;

static int clk_debugfs_register_one(struct clk *c)
{
      int err;
      struct dentry *d, *child, *child_tmp;
      struct clk *pa = c->parent;
      char s[255];
      char *p = s;

      p += sprintf(p, "%s", c->name);

      if (c->id >= 0)
            sprintf(p, ":%d", c->id);

      d = debugfs_create_dir(s, pa ? pa->dent : clk_debugfs_root);
      if (!d)
            return -ENOMEM;

      c->dent = d;

      d = debugfs_create_u8("usecount", S_IRUGO, c->dent, (u8 *)&c->usage);
      if (!d) {
            err = -ENOMEM;
            goto err_out;
      }

      d = debugfs_create_u32("rate", S_IRUGO, c->dent, (u32 *)&c->rate);
      if (!d) {
            err = -ENOMEM;
            goto err_out;
      }
      return 0;

err_out:
      d = c->dent;
      list_for_each_entry_safe(child, child_tmp, &d->d_subdirs, d_u.d_child)
            debugfs_remove(child);
      debugfs_remove(c->dent);
      return err;
}

static int clk_debugfs_register(struct clk *c)
{
      int err;
      struct clk *pa = c->parent;

      if (pa && !pa->dent) {
            err = clk_debugfs_register(pa);
            if (err)
                  return err;
      }

      if (!c->dent) {
            err = clk_debugfs_register_one(c);
            if (err)
                  return err;
      }
      return 0;
}

static int __init clk_debugfs_init(void)
{
      struct clk *c;
      struct dentry *d;
      int err;

      d = debugfs_create_dir("clock", NULL);
      if (!d)
            return -ENOMEM;
      clk_debugfs_root = d;

      list_for_each_entry(c, &clocks, list) {
            err = clk_debugfs_register(c);
            if (err)
                  goto err_out;
      }
      return 0;

err_out:
      debugfs_remove_recursive(clk_debugfs_root);
      return err;
}
late_initcall(clk_debugfs_init);

#endif /* defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS) */

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