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kernel/linux-rt-4.4.41/drivers/char/hw_random/ixp4xx-rng.c 1.63 KB
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  /*
   * drivers/char/hw_random/ixp4xx-rng.c
   *
   * RNG driver for Intel IXP4xx family of NPUs
   *
   * Author: Deepak Saxena <dsaxena@plexity.net>
   *
   * Copyright 2005 (c) MontaVista Software, Inc.
   *
   * Fixes by Michael Buesch
   *
   * This file is licensed under  the terms of the GNU General Public
   * License version 2. This program is licensed "as is" without any
   * warranty of any kind, whether express or implied.
   */
  
  #include <linux/kernel.h>
  #include <linux/types.h>
  #include <linux/module.h>
  #include <linux/moduleparam.h>
  #include <linux/init.h>
  #include <linux/bitops.h>
  #include <linux/hw_random.h>
  
  #include <asm/io.h>
  #include <mach/hardware.h>
  
  
  static int ixp4xx_rng_data_read(struct hwrng *rng, u32 *buffer)
  {
  	void __iomem * rng_base = (void __iomem *)rng->priv;
  
  	*buffer = __raw_readl(rng_base);
  
  	return 4;
  }
  
  static struct hwrng ixp4xx_rng_ops = {
  	.name		= "ixp4xx",
  	.data_read	= ixp4xx_rng_data_read,
  };
  
  static int __init ixp4xx_rng_init(void)
  {
  	void __iomem * rng_base;
  	int err;
  
  	if (!cpu_is_ixp46x()) /* includes IXP455 */
  		return -ENOSYS;
  
  	rng_base = ioremap(0x70002100, 4);
  	if (!rng_base)
  		return -ENOMEM;
  	ixp4xx_rng_ops.priv = (unsigned long)rng_base;
  	err = hwrng_register(&ixp4xx_rng_ops);
  	if (err)
  		iounmap(rng_base);
  
  	return err;
  }
  
  static void __exit ixp4xx_rng_exit(void)
  {
  	void __iomem * rng_base = (void __iomem *)ixp4xx_rng_ops.priv;
  
  	hwrng_unregister(&ixp4xx_rng_ops);
  	iounmap(rng_base);
  }
  
  module_init(ixp4xx_rng_init);
  module_exit(ixp4xx_rng_exit);
  
  MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
  MODULE_DESCRIPTION("H/W Pseudo-Random Number Generator (RNG) driver for IXP45x/46x");
  MODULE_LICENSE("GPL");