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
22 struct octeon_rng {
23 struct hwrng ops;
24 void __iomem *control_status;
25 void __iomem *result;
26 };
27
octeon_rng_init(struct hwrng * rng)28 static 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((__force u64)p->control_status, ctl.u64);
37 return 0;
38 }
39
octeon_rng_cleanup(struct hwrng * rng)40 static 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((__force u64)p->control_status, ctl.u64);
48 }
49
octeon_rng_data_read(struct hwrng * rng,u32 * data)50 static 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((__force u64)p->result);
55 return sizeof(u32);
56 }
57
octeon_rng_probe(struct platform_device * pdev)58 static 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(&pdev->dev,
85 res_ports->start,
86 sizeof(u64));
87 if (!rng->control_status)
88 return -ENOENT;
89
90 rng->result = devm_ioremap(&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 = devm_hwrng_register(&pdev->dev, &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
108 static struct platform_driver octeon_rng_driver = {
109 .driver = {
110 .name = "octeon_rng",
111 },
112 .probe = octeon_rng_probe,
113 };
114
115 module_platform_driver(octeon_rng_driver);
116
117 MODULE_AUTHOR("David Daney");
118 MODULE_LICENSE("GPL");
119