[mirror_ubuntu-artful-kernel.git] / drivers / char / hw_random / geode-rng.c

/*
 * RNG driver for AMD Geode RNGs
 *
 * Copyright 2005 (c) MontaVista Software, Inc.
 *
 * with the majority of the code coming from:
 *
 * Hardware driver for the Intel/AMD/VIA Random Number Generators (RNG)
 * (c) Copyright 2003 Red Hat Inc <jgarzik@redhat.com>
 *
 * derived from
 *
 * Hardware driver for the AMD 768 Random Number Generator (RNG)
 * (c) Copyright 2001 Red Hat Inc
 *
 * derived from
 *
 * Hardware driver for Intel i810 Random Number Generator (RNG)
 * Copyright 2000,2001 Jeff Garzik <jgarzik@pobox.com>
 * Copyright 2000,2001 Philipp Rumpf <prumpf@mandrakesoft.com>
 *
 * 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/module.h>
#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/hw_random.h>
#include <linux/delay.h>
#include <asm/io.h>


#define PFX	KBUILD_MODNAME ": "

#define GEODE_RNG_DATA_REG   0x50
#define GEODE_RNG_STATUS_REG 0x54

/*
 * Data for PCI driver interface
 *
 * This data only exists for exporting the supported
 * PCI ids via MODULE_DEVICE_TABLE.  We do not actually
 * register a pci_driver, because someone else might one day
 * want to register another driver on the same PCI id.
 */
static const struct pci_device_id pci_tbl[] = {
	{ PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_LX_AES), 0, },
	{ 0, },	/* terminate list */
};
MODULE_DEVICE_TABLE(pci, pci_tbl);


static int geode_rng_data_read(struct hwrng *rng, u32 *data)
{
	void __iomem *mem = (void __iomem *)rng->priv;

	*data = readl(mem + GEODE_RNG_DATA_REG);

	return 4;
}

static int geode_rng_data_present(struct hwrng *rng, int wait)
{
	void __iomem *mem = (void __iomem *)rng->priv;
	int data, i;

	for (i = 0; i < 20; i++) {
		data = !!(readl(mem + GEODE_RNG_STATUS_REG));
		if (data || !wait)
			break;
		udelay(10);
	}
	return data;
}


static struct hwrng geode_rng = {
	.name		= "geode",
	.data_present	= geode_rng_data_present,
	.data_read	= geode_rng_data_read,
};


static int __init mod_init(void)
{
	int err = -ENODEV;
	struct pci_dev *pdev = NULL;
	const struct pci_device_id *ent;
	void __iomem *mem;
	unsigned long rng_base;

	for_each_pci_dev(pdev) {
		ent = pci_match_id(pci_tbl, pdev);
		if (ent)
			goto found;
	}
	/* Device not found. */
	goto out;

found:
	rng_base = pci_resource_start(pdev, 0);
	if (rng_base == 0)
		goto out;
	err = -ENOMEM;
	mem = ioremap(rng_base, 0x58);
	if (!mem)
		goto out;
	geode_rng.priv = (unsigned long)mem;

	pr_info("AMD Geode RNG detected\n");
	err = hwrng_register(&geode_rng);
	if (err) {
		pr_err(PFX "RNG registering failed (%d)\n",
		       err);
		goto err_unmap;
	}
out:
	return err;

err_unmap:
	iounmap(mem);
	goto out;
}

static void __exit mod_exit(void)
{
	void __iomem *mem = (void __iomem *)geode_rng.priv;

	hwrng_unregister(&geode_rng);
	iounmap(mem);
}

module_init(mod_init);
module_exit(mod_exit);

MODULE_DESCRIPTION("H/W RNG driver for AMD Geode LX CPUs");
MODULE_LICENSE("GPL");
Commit	Line	Data
ef5d8627 MB	1	/*
	2	* RNG driver for AMD Geode RNGs
	3	*
	4	* Copyright 2005 (c) MontaVista Software, Inc.
	5	*
	6	* with the majority of the code coming from:
	7	*
	8	* Hardware driver for the Intel/AMD/VIA Random Number Generators (RNG)
	9	* (c) Copyright 2003 Red Hat Inc <jgarzik@redhat.com>
	10	*
	11	* derived from
	12	*
	13	* Hardware driver for the AMD 768 Random Number Generator (RNG)
77122d0b	14	* (c) Copyright 2001 Red Hat Inc
ef5d8627 MB	15	*
	16	* derived from
	17	*
	18	* Hardware driver for Intel i810 Random Number Generator (RNG)
	19	* Copyright 2000,2001 Jeff Garzik <jgarzik@pobox.com>
	20	* Copyright 2000,2001 Philipp Rumpf <prumpf@mandrakesoft.com>
	21	*
	22	* This file is licensed under the terms of the GNU General Public
	23	* License version 2. This program is licensed "as is" without any
	24	* warranty of any kind, whether express or implied.
	25	*/
	26
	27	#include <linux/module.h>
	28	#include <linux/kernel.h>
	29	#include <linux/pci.h>
	30	#include <linux/hw_random.h>
984e976f	31	#include <linux/delay.h>
ef5d8627 MB	32	#include <asm/io.h>
	33
	34
	35	#define PFX KBUILD_MODNAME ": "
	36
	37	#define GEODE_RNG_DATA_REG 0x50
	38	#define GEODE_RNG_STATUS_REG 0x54
	39
	40	/*
	41	* Data for PCI driver interface
	42	*
	43	* This data only exists for exporting the supported
	44	* PCI ids via MODULE_DEVICE_TABLE. We do not actually
	45	* register a pci_driver, because someone else might one day
	46	* want to register another driver on the same PCI id.
	47	*/
	48	static const struct pci_device_id pci_tbl[] = {
409a7363	49	{ PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_LX_AES), 0, },
ef5d8627 MB	50	{ 0, }, /* terminate list */
	51	};
	52	MODULE_DEVICE_TABLE(pci, pci_tbl);
	53
	54
	55	static int geode_rng_data_read(struct hwrng rng, u32 data)
	56	{
	57	void __iomem mem = (void __iomem )rng->priv;
	58
	59	*data = readl(mem + GEODE_RNG_DATA_REG);
	60
	61	return 4;
	62	}
	63
984e976f	64	static int geode_rng_data_present(struct hwrng *rng, int wait)
ef5d8627 MB	65	{
ef5d8627 MB	66	void __iomem mem = (void __iomem )rng->priv;
984e976f	67	int data, i;
ef5d8627	68
984e976f PM	69	for (i = 0; i < 20; i++) {
	70	data = !!(readl(mem + GEODE_RNG_STATUS_REG));
	71	if (data \|\| !wait)
	72	break;
	73	udelay(10);
	74	}
	75	return data;
ef5d8627 MB	76	}
	77
	78
	79	static struct hwrng geode_rng = {
	80	.name = "geode",
	81	.data_present = geode_rng_data_present,
	82	.data_read = geode_rng_data_read,
	83	};
	84
	85
	86	static int __init mod_init(void)
	87	{
	88	int err = -ENODEV;
	89	struct pci_dev *pdev = NULL;
	90	const struct pci_device_id *ent;
	91	void __iomem *mem;
	92	unsigned long rng_base;
	93
	94	for_each_pci_dev(pdev) {
	95	ent = pci_match_id(pci_tbl, pdev);
	96	if (ent)
	97	goto found;
	98	}
	99	/* Device not found. */
	100	goto out;
	101
	102	found:
	103	rng_base = pci_resource_start(pdev, 0);
	104	if (rng_base == 0)
	105	goto out;
	106	err = -ENOMEM;
	107	mem = ioremap(rng_base, 0x58);
	108	if (!mem)
	109	goto out;
	110	geode_rng.priv = (unsigned long)mem;
	111
7a1ae9c0	112	pr_info("AMD Geode RNG detected\n");
ef5d8627 MB	113	err = hwrng_register(&geode_rng);
ef5d8627 MB	114	if (err) {
7a1ae9c0	115	pr_err(PFX "RNG registering failed (%d)\n",
ef5d8627	116	err);
072d3d1a	117	goto err_unmap;
ef5d8627 MB	118	}
	119	out:
	120	return err;
072d3d1a MB	121
	122	err_unmap:
	123	iounmap(mem);
	124	goto out;
ef5d8627 MB	125	}
	126
	127	static void __exit mod_exit(void)
	128	{
	129	void __iomem mem = (void __iomem )geode_rng.priv;
	130
	131	hwrng_unregister(&geode_rng);
	132	iounmap(mem);
	133	}
	134
56fb5fe9	135	module_init(mod_init);
ef5d8627 MB	136	module_exit(mod_exit);
	137
	138	MODULE_DESCRIPTION("H/W RNG driver for AMD Geode LX CPUs");
	139	MODULE_LICENSE("GPL");