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spba.c

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/*
 * Copyright 2004-2009 Freescale Semiconductor, Inc. All Rights Reserved.
 */

/*
 * The code contained herein is licensed under the GNU General Public
 * License. You may obtain a copy of the GNU General Public License
 * Version 2 or later at the following locations:
 *
 * http://www.opensource.org/licenses/gpl-license.html
 * http://www.gnu.org/copyleft/gpl.html
 */

#include <linux/types.h>
#include <linux/clk.h>
#include <linux/module.h>
#include <linux/io.h>
#include <mach/hardware.h>
#include <mach/spba.h>

/*!
 * @file plat-mxc/spba.c
 *
 * @brief This file contains the SPBA API implementation details.
 *
 * @ingroup SPBA
 */

static DEFINE_SPINLOCK(spba_lock);

#define SPBA_MASTER_MIN                 1
#define SPBA_MASTER_MAX                 7

/*!
 * the base addresses for the SPBA modules
 */
00037 static unsigned long spba_base = (unsigned long)IO_ADDRESS(SPBA_CTRL_BASE_ADDR);

/*!
 * SPBA clock
 */
00042 static struct clk *spba_clk;
/*!
 * This function allows the three masters (A, B, C) to take ownership of a
 * shared peripheral.
 *
 * @param  mod          specified module as defined in \b enum \b #spba_module
 * @param  master       one of more (or-ed together) masters as defined in \b enum \b #spba_masters
 *
 * @return 0 if successful; -1 otherwise.
 */
00052 int spba_take_ownership(int mod, int master)
{
      unsigned long spba_flags;
      __u32 rtn_val = -1;

      if (master < SPBA_MASTER_MIN || master > SPBA_MASTER_MAX) {
            printk("spba_take_ownership() invalide master= %d\n", master);
            BUG();            /* oops */
      }

      if (spba_clk == NULL)
            spba_clk = clk_get(NULL, "spba_clk");

      clk_enable(spba_clk);

      spin_lock_irqsave(&spba_lock, spba_flags);
      __raw_writel(master, spba_base + mod);

      if ((__raw_readl(spba_base + mod) & MXC_SPBA_RAR_MASK) == master) {
            rtn_val = 0;
      }

      spin_unlock_irqrestore(&spba_lock, spba_flags);

      clk_disable(spba_clk);
      return rtn_val;
}

/*!
 * This function releases the ownership for a shared peripheral.
 *
 * @param  mod          specified module as defined in \b enum \b #spba_module
 * @param  master       one of more (or-ed together) masters as defined in \b enum \b #spba_masters
 *
 * @return 0 if successful; -1 otherwise.
 */
00088 int spba_rel_ownership(int mod, int master)
{
      unsigned long spba_flags;
      volatile unsigned long rar;

      if (master < SPBA_MASTER_MIN || master > SPBA_MASTER_MAX) {
            printk("spba_take_ownership() invalide master= %d\n", master);
            BUG();            /* oops */
      }

      if (spba_clk == NULL)
            spba_clk = clk_get(NULL, "spba_clk");

      clk_enable(spba_clk);

      if ((__raw_readl(spba_base + mod) & master) == 0) {
            clk_disable(spba_clk);
            return 0;   /* does not own it */
      }

      spin_lock_irqsave(&spba_lock, spba_flags);

      /* Since only the last 3 bits are writeable, doesn't need to mask off
         bits 31-3 */
      rar = __raw_readl(spba_base + mod) & (~master);
      __raw_writel(rar, spba_base + mod);

      if ((__raw_readl(spba_base + mod) & master) != 0) {
            spin_unlock_irqrestore(&spba_lock, spba_flags);
            clk_disable(spba_clk);
            return -1;
      }

      spin_unlock_irqrestore(&spba_lock, spba_flags);

      clk_disable(spba_clk);

      return 0;
}

EXPORT_SYMBOL(spba_take_ownership);
EXPORT_SYMBOL(spba_rel_ownership);

MODULE_AUTHOR("Freescale Semiconductor, Inc.");
MODULE_DESCRIPTION("SPBA");
MODULE_LICENSE("GPL");

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