[mirror_ubuntu-zesty-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/delay.h>
#include <linux/hw_random.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>

#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)
{
	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) {
			rng_base = pci_resource_start(pdev, 0);
			if (rng_base == 0)
				return -ENODEV;

			mem = devm_ioremap(&pdev->dev, rng_base, 0x58);
			if (!mem)
				return -ENOMEM;
			geode_rng.priv = (unsigned long)mem;

			pr_info("AMD Geode RNG detected\n");
			return devm_hwrng_register(&pdev->dev, &geode_rng);
		}
	}

	/* Device not found. */
	return -ENODEV;
}

static void __exit mod_exit(void)
{
}

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
e9afc746 PM	27	#include <linux/delay.h>
	28	#include <linux/hw_random.h>
	29	#include <linux/io.h>
ef5d8627	30	#include <linux/kernel.h>
e9afc746	31	#include <linux/module.h>
ef5d8627	32	#include <linux/pci.h>
ef5d8627	33
ef5d8627 MB	34	#define GEODE_RNG_DATA_REG 0x50
	35	#define GEODE_RNG_STATUS_REG 0x54
	36
	37	/*
	38	* Data for PCI driver interface
	39	*
	40	* This data only exists for exporting the supported
	41	* PCI ids via MODULE_DEVICE_TABLE. We do not actually
	42	* register a pci_driver, because someone else might one day
	43	* want to register another driver on the same PCI id.
	44	*/
	45	static const struct pci_device_id pci_tbl[] = {
409a7363	46	{ PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_LX_AES), 0, },
ef5d8627 MB	47	{ 0, }, /* terminate list */
	48	};
	49	MODULE_DEVICE_TABLE(pci, pci_tbl);
	50
	51
	52	static int geode_rng_data_read(struct hwrng rng, u32 data)
	53	{
	54	void __iomem mem = (void __iomem )rng->priv;
	55
	56	*data = readl(mem + GEODE_RNG_DATA_REG);
	57
	58	return 4;
	59	}
	60
984e976f	61	static int geode_rng_data_present(struct hwrng *rng, int wait)
ef5d8627 MB	62	{
ef5d8627 MB	63	void __iomem mem = (void __iomem )rng->priv;
984e976f	64	int data, i;
ef5d8627	65
984e976f PM	66	for (i = 0; i < 20; i++) {
	67	data = !!(readl(mem + GEODE_RNG_STATUS_REG));
	68	if (data \|\| !wait)
	69	break;
	70	udelay(10);
	71	}
	72	return data;
ef5d8627 MB	73	}
	74
	75
	76	static struct hwrng geode_rng = {
	77	.name = "geode",
	78	.data_present = geode_rng_data_present,
	79	.data_read = geode_rng_data_read,
	80	};
	81
	82
	83	static int __init mod_init(void)
	84	{
ef5d8627 MB	85	struct pci_dev *pdev = NULL;
	86	const struct pci_device_id *ent;
	87	void __iomem *mem;
	88	unsigned long rng_base;
	89
	90	for_each_pci_dev(pdev) {
	91	ent = pci_match_id(pci_tbl, pdev);
6e9b5e76 PM	92	if (ent) {
	93	rng_base = pci_resource_start(pdev, 0);
	94	if (rng_base == 0)
	95	return -ENODEV;
	96
	97	mem = devm_ioremap(&pdev->dev, rng_base, 0x58);
104a32e8 WY	98	if (!mem)
104a32e8 WY	99	return -ENOMEM;
6e9b5e76 PM	100	geode_rng.priv = (unsigned long)mem;
	101
	102	pr_info("AMD Geode RNG detected\n");
	103	return devm_hwrng_register(&pdev->dev, &geode_rng);
	104	}
ef5d8627	105	}
072d3d1a	106
6e9b5e76 PM	107	/* Device not found. */
6e9b5e76 PM	108	return -ENODEV;
ef5d8627 MB	109	}
	110
	111	static void __exit mod_exit(void)
	112	{
ef5d8627 MB	113	}
ef5d8627 MB	114
56fb5fe9	115	module_init(mod_init);
ef5d8627 MB	116	module_exit(mod_exit);
	117
	118	MODULE_DESCRIPTION("H/W RNG driver for AMD Geode LX CPUs");
	119	MODULE_LICENSE("GPL");