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mailbox.c

/*
 * Mailbox reservation modules for DSP
 *
 * Copyright (C) 2006 Nokia Corporation
 * Written by: Hiroshi DOYU <Hiroshi.DOYU@nokia.com>
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */

#include <linux/kernel.h>
#include <linux/resource.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <mach/mailbox.h>
#include <mach/irqs.h>
#include <asm/io.h>

#define MAILBOX_ARM2DSP1            0x00
#define MAILBOX_ARM2DSP1b           0x04
#define MAILBOX_DSP2ARM1            0x08
#define MAILBOX_DSP2ARM1b           0x0c
#define MAILBOX_DSP2ARM2            0x10
#define MAILBOX_DSP2ARM2b           0x14
#define MAILBOX_ARM2DSP1_Flag       0x18
#define MAILBOX_DSP2ARM1_Flag       0x1c
#define MAILBOX_DSP2ARM2_Flag       0x20

unsigned long mbox_base;

struct omap_mbox1_fifo {
      unsigned long cmd;
      unsigned long data;
      unsigned long flag;
};

struct omap_mbox1_priv {
      struct omap_mbox1_fifo tx_fifo;
      struct omap_mbox1_fifo rx_fifo;
};

static inline int mbox_read_reg(unsigned int reg)
{
      return __raw_readw(mbox_base + reg);
}

static inline void mbox_write_reg(unsigned int val, unsigned int reg)
{
      __raw_writew(val, mbox_base + reg);
}

/* msg */
static mbox_msg_t omap1_mbox_fifo_read(struct omap_mbox *mbox)
{
      struct omap_mbox1_fifo *fifo =
            &((struct omap_mbox1_priv *)mbox->priv)->rx_fifo;
      mbox_msg_t msg;

      msg = mbox_read_reg(fifo->data);
      msg |= ((mbox_msg_t) mbox_read_reg(fifo->cmd)) << 16;

      return msg;
}

static void
omap1_mbox_fifo_write(struct omap_mbox *mbox, mbox_msg_t msg)
{
      struct omap_mbox1_fifo *fifo =
            &((struct omap_mbox1_priv *)mbox->priv)->tx_fifo;

      mbox_write_reg(msg & 0xffff, fifo->data);
      mbox_write_reg(msg >> 16, fifo->cmd);
}

static int omap1_mbox_fifo_empty(struct omap_mbox *mbox)
{
      return 0;
}

static int omap1_mbox_fifo_full(struct omap_mbox *mbox)
{
      struct omap_mbox1_fifo *fifo =
            &((struct omap_mbox1_priv *)mbox->priv)->rx_fifo;

      return (mbox_read_reg(fifo->flag));
}

/* irq */
static void
omap1_mbox_enable_irq(struct omap_mbox *mbox, omap_mbox_type_t irq)
{
      if (irq == IRQ_RX)
            enable_irq(mbox->irq);
}

static void
omap1_mbox_disable_irq(struct omap_mbox *mbox, omap_mbox_type_t irq)
{
      if (irq == IRQ_RX)
            disable_irq(mbox->irq);
}

static int
omap1_mbox_is_irq(struct omap_mbox *mbox, omap_mbox_type_t irq)
{
      if (irq == IRQ_TX)
            return 0;
      return 1;
}

static struct omap_mbox_ops omap1_mbox_ops = {
      .type       = OMAP_MBOX_TYPE1,
      .fifo_read  = omap1_mbox_fifo_read,
      .fifo_write = omap1_mbox_fifo_write,
      .fifo_empty = omap1_mbox_fifo_empty,
      .fifo_full  = omap1_mbox_fifo_full,
      .enable_irq = omap1_mbox_enable_irq,
      .disable_irq      = omap1_mbox_disable_irq,
      .is_irq           = omap1_mbox_is_irq,
};

/* FIXME: the following struct should be created automatically by the user id */

/* DSP */
static struct omap_mbox1_priv omap1_mbox_dsp_priv = {
      .tx_fifo = {
            .cmd  = MAILBOX_ARM2DSP1b,
            .data = MAILBOX_ARM2DSP1,
            .flag = MAILBOX_ARM2DSP1_Flag,
      },
      .rx_fifo = {
            .cmd  = MAILBOX_DSP2ARM1b,
            .data = MAILBOX_DSP2ARM1,
            .flag = MAILBOX_DSP2ARM1_Flag,
      },
};

struct omap_mbox mbox_dsp_info = {
      .name = "dsp",
      .ops  = &omap1_mbox_ops,
      .priv = &omap1_mbox_dsp_priv,
};
EXPORT_SYMBOL(mbox_dsp_info);

static int __init omap1_mbox_probe(struct platform_device *pdev)
{
      struct resource *res;
      int ret = 0;

      if (pdev->num_resources != 2) {
            dev_err(&pdev->dev, "invalid number of resources: %d\n",
                  pdev->num_resources);
            return -ENODEV;
      }

      /* MBOX base */
      res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
      if (unlikely(!res)) {
            dev_err(&pdev->dev, "invalid mem resource\n");
            return -ENODEV;
      }
      mbox_base = res->start;

      /* DSP IRQ */
      res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
      if (unlikely(!res)) {
            dev_err(&pdev->dev, "invalid irq resource\n");
            return -ENODEV;
      }
      mbox_dsp_info.irq = res->start;

      ret = omap_mbox_register(&mbox_dsp_info);

      return ret;
}

static int omap1_mbox_remove(struct platform_device *pdev)
{
      omap_mbox_unregister(&mbox_dsp_info);

      return 0;
}

static struct platform_driver omap1_mbox_driver = {
      .probe      = omap1_mbox_probe,
      .remove     = omap1_mbox_remove,
      .driver     = {
            .name = "mailbox",
      },
};

static int __init omap1_mbox_init(void)
{
      return platform_driver_register(&omap1_mbox_driver);
}

static void __exit omap1_mbox_exit(void)
{
      platform_driver_unregister(&omap1_mbox_driver);
}

module_init(omap1_mbox_init);
module_exit(omap1_mbox_exit);

MODULE_LICENSE("GPL");

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