/*
   * Copyright (C) 2004 IBM Corporation
   *
   * Authors:
   * Leendert van Doorn <leendert@watson.ibm.com>
   * Dave Safford <safford@watson.ibm.com>
   * Reiner Sailer <sailer@watson.ibm.com>
   * Kylene Hall <kjhall@us.ibm.com>
   *

   * Maintained by: <tpmdd-devel@lists.sourceforge.net>

   *
   * Device driver for TCG/TCPA TPM (trusted platform module).
   * Specifications at www.trustedcomputinggroup.org	 
   *
   * 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, version 2 of the
   * License.
   * 
   */
  
  #include "tpm.h"

  #include "tpm_atmel.h"

  
  /* write status bits */

  enum tpm_atmel_write_status {
  	ATML_STATUS_ABORT = 0x01,
  	ATML_STATUS_LASTBYTE = 0x04
  };

  /* read status bits */

  enum tpm_atmel_read_status {
  	ATML_STATUS_BUSY = 0x01,
  	ATML_STATUS_DATA_AVAIL = 0x02,
  	ATML_STATUS_REWRITE = 0x04,
  	ATML_STATUS_READY = 0x08
  };

  static int tpm_atml_recv(struct tpm_chip *chip, u8 *buf, size_t count)

  {

  	struct tpm_atmel_priv *priv = dev_get_drvdata(&chip->dev);

  	u8 status, *hdr = buf;
  	u32 size;
  	int i;
  	__be32 *native_size;
  
  	/* start reading header */
  	if (count < 6)
  		return -EIO;
  
  	for (i = 0; i < 6; i++) {

  		status = ioread8(priv->iobase + 1);

  		if ((status & ATML_STATUS_DATA_AVAIL) == 0) {

  			dev_err(&chip->dev, "error reading header
  ");

  			return -EIO;
  		}

  		*buf++ = ioread8(priv->iobase);

  	}
  
  	/* size of the data received */
  	native_size = (__force __be32 *) (hdr + 2);
  	size = be32_to_cpu(*native_size);
  
  	if (count < size) {

  		dev_err(&chip->dev,

  			"Recv size(%d) less than available space
  ", size);
  		for (; i < size; i++) {	/* clear the waiting data anyway */

  			status = ioread8(priv->iobase + 1);

  			if ((status & ATML_STATUS_DATA_AVAIL) == 0) {

  				dev_err(&chip->dev, "error reading data
  ");

  				return -EIO;
  			}
  		}
  		return -EIO;
  	}
  
  	/* read all the data available */
  	for (; i < size; i++) {

  		status = ioread8(priv->iobase + 1);

  		if ((status & ATML_STATUS_DATA_AVAIL) == 0) {

  			dev_err(&chip->dev, "error reading data
  ");

  			return -EIO;
  		}

  		*buf++ = ioread8(priv->iobase);

  	}
  
  	/* make sure data available is gone */

  	status = ioread8(priv->iobase + 1);

  	if (status & ATML_STATUS_DATA_AVAIL) {

  		dev_err(&chip->dev, "data available is stuck
  ");

  		return -EIO;
  	}
  
  	return size;
  }

  static int tpm_atml_send(struct tpm_chip *chip, u8 *buf, size_t count)

  {

  	struct tpm_atmel_priv *priv = dev_get_drvdata(&chip->dev);

  	int i;

  	dev_dbg(&chip->dev, "tpm_atml_send:
  ");

  	for (i = 0; i < count; i++) {

  		dev_dbg(&chip->dev, "%d 0x%x(%d)
  ",  i, buf[i], buf[i]);

  		iowrite8(buf[i], priv->iobase);

  	}
  
  	return count;
  }
  
  static void tpm_atml_cancel(struct tpm_chip *chip)
  {

  	struct tpm_atmel_priv *priv = dev_get_drvdata(&chip->dev);

  
  	iowrite8(ATML_STATUS_ABORT, priv->iobase + 1);

  }

  static u8 tpm_atml_status(struct tpm_chip *chip)
  {

  	struct tpm_atmel_priv *priv = dev_get_drvdata(&chip->dev);

  
  	return ioread8(priv->iobase + 1);

  }

  static bool tpm_atml_req_canceled(struct tpm_chip *chip, u8 status)
  {
  	return (status == ATML_STATUS_READY);
  }

  static const struct tpm_class_ops tpm_atmel = {

  	.recv = tpm_atml_recv,
  	.send = tpm_atml_send,
  	.cancel = tpm_atml_cancel,

  	.status = tpm_atml_status,

  	.req_complete_mask = ATML_STATUS_BUSY | ATML_STATUS_DATA_AVAIL,
  	.req_complete_val = ATML_STATUS_DATA_AVAIL,

  	.req_canceled = tpm_atml_req_canceled,

  };

  static struct platform_device *pdev;

  static void atml_plat_remove(void)

  {

  	struct tpm_chip *chip = dev_get_drvdata(&pdev->dev);

  	struct tpm_atmel_priv *priv = dev_get_drvdata(&chip->dev);

  	if (chip) {

  		tpm_chip_unregister(chip);

  		if (priv->have_region)

  			atmel_release_region(priv->base, priv->region_size);

  		atmel_put_base_addr(priv->iobase);

  		platform_device_unregister(pdev);

  	}
  }

  static SIMPLE_DEV_PM_OPS(tpm_atml_pm, tpm_pm_suspend, tpm_pm_resume);

  static struct platform_driver atml_drv = {
  	.driver = {
  		.name = "tpm_atmel",

  		.pm		= &tpm_atml_pm,

  	},

  };
  
  static int __init init_atmel(void)

  {

  	int rc = 0;

  	void __iomem *iobase = NULL;
  	int have_region, region_size;
  	unsigned long base;
  	struct  tpm_chip *chip;

  	struct tpm_atmel_priv *priv;

  	rc = platform_driver_register(&atml_drv);

  	if (rc)
  		return rc;

  	if ((iobase = atmel_get_base_addr(&base, &region_size)) == NULL) {

  		rc = -ENODEV;
  		goto err_unreg_drv;

  	}

  	have_region =

  	    (atmel_request_region

  	     (base, region_size, "tpm_atmel0") == NULL) ? 0 : 1;

  	pdev = platform_device_register_simple("tpm_atmel", -1, NULL, 0);
  	if (IS_ERR(pdev)) {

  		rc = PTR_ERR(pdev);
  		goto err_rel_reg;

  	}

  	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
  	if (!priv) {
  		rc = -ENOMEM;
  		goto err_unreg_dev;
  	}

  	priv->iobase = iobase;

  	priv->base = base;

  	priv->have_region = have_region;
  	priv->region_size = region_size;

  	chip = tpmm_chip_alloc(&pdev->dev, &tpm_atmel);
  	if (IS_ERR(chip)) {
  		rc = PTR_ERR(chip);

  		goto err_unreg_dev;

  	}

  	dev_set_drvdata(&chip->dev, priv);

  	rc = tpm_chip_register(chip);
  	if (rc)
  		goto err_unreg_dev;

  	return 0;

  
  err_unreg_dev:
  	platform_device_unregister(pdev);
  err_rel_reg:

  	atmel_put_base_addr(iobase);
  	if (have_region)
  		atmel_release_region(base,
  				     region_size);

  err_unreg_drv:

  	platform_driver_unregister(&atml_drv);

  	return rc;

  }
  
  static void __exit cleanup_atmel(void)
  {

  	platform_driver_unregister(&atml_drv);

  	atml_plat_remove();

  }
  
  module_init(init_atmel);
  module_exit(cleanup_atmel);
  
  MODULE_AUTHOR("Leendert van Doorn (leendert@watson.ibm.com)");
  MODULE_DESCRIPTION("TPM Driver");
  MODULE_VERSION("2.0");
  MODULE_LICENSE("GPL");