1/*
2 * Hardware Random Number Generator support for Cavium Networks
3 * Octeon processor family.
4 *
5 * This file is subject to the terms and conditions of the GNU General Public
6 * License.  See the file "COPYING" in the main directory of this archive
7 * for more details.
8 *
9 * Copyright (C) 2009 Cavium Networks
10 */
11
12#include <linux/module.h>
13#include <linux/platform_device.h>
14#include <linux/device.h>
15#include <linux/hw_random.h>
16#include <linux/io.h>
17#include <linux/gfp.h>
18
19#include <asm/octeon/octeon.h>
20#include <asm/octeon/cvmx-rnm-defs.h>
21
22struct octeon_rng {
23	struct hwrng ops;
24	void __iomem *control_status;
25	void __iomem *result;
26};
27
28static int octeon_rng_init(struct hwrng *rng)
29{
30	union cvmx_rnm_ctl_status ctl;
31	struct octeon_rng *p = container_of(rng, struct octeon_rng, ops);
32
33	ctl.u64 = 0;
34	ctl.s.ent_en = 1; /* Enable the entropy source.  */
35	ctl.s.rng_en = 1; /* Enable the RNG hardware.  */
36	cvmx_write_csr((u64)p->control_status, ctl.u64);
37	return 0;
38}
39
40static void octeon_rng_cleanup(struct hwrng *rng)
41{
42	union cvmx_rnm_ctl_status ctl;
43	struct octeon_rng *p = container_of(rng, struct octeon_rng, ops);
44
45	ctl.u64 = 0;
46	/* Disable everything.  */
47	cvmx_write_csr((u64)p->control_status, ctl.u64);
48}
49
50static int octeon_rng_data_read(struct hwrng *rng, u32 *data)
51{
52	struct octeon_rng *p = container_of(rng, struct octeon_rng, ops);
53
54	*data = cvmx_read64_uint32((u64)p->result);
55	return sizeof(u32);
56}
57
58static int octeon_rng_probe(struct platform_device *pdev)
59{
60	struct resource *res_ports;
61	struct resource *res_result;
62	struct octeon_rng *rng;
63	int ret;
64	struct hwrng ops = {
65		.name = "octeon",
66		.init = octeon_rng_init,
67		.cleanup = octeon_rng_cleanup,
68		.data_read = octeon_rng_data_read
69	};
70
71	rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL);
72	if (!rng)
73		return -ENOMEM;
74
75	res_ports = platform_get_resource(pdev, IORESOURCE_MEM, 0);
76	if (!res_ports)
77		return -ENOENT;
78
79	res_result = platform_get_resource(pdev, IORESOURCE_MEM, 1);
80	if (!res_result)
81		return -ENOENT;
82
83
84	rng->control_status = devm_ioremap_nocache(&pdev->dev,
85						   res_ports->start,
86						   sizeof(u64));
87	if (!rng->control_status)
88		return -ENOENT;
89
90	rng->result = devm_ioremap_nocache(&pdev->dev,
91					   res_result->start,
92					   sizeof(u64));
93	if (!rng->result)
94		return -ENOENT;
95
96	rng->ops = ops;
97
98	platform_set_drvdata(pdev, &rng->ops);
99	ret = hwrng_register(&rng->ops);
100	if (ret)
101		return -ENOENT;
102
103	dev_info(&pdev->dev, "Octeon Random Number Generator\n");
104
105	return 0;
106}
107
108static int octeon_rng_remove(struct platform_device *pdev)
109{
110	struct hwrng *rng = platform_get_drvdata(pdev);
111
112	hwrng_unregister(rng);
113
114	return 0;
115}
116
117static struct platform_driver octeon_rng_driver = {
118	.driver = {
119		.name		= "octeon_rng",
120	},
121	.probe		= octeon_rng_probe,
122	.remove		= octeon_rng_remove,
123};
124
125module_platform_driver(octeon_rng_driver);
126
127MODULE_AUTHOR("David Daney");
128MODULE_LICENSE("GPL");
129