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 
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((u64)p->control_status, ctl.u64);
37 	return 0;
38 }
39 
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((u64)p->control_status, ctl.u64);
48 }
49 
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((u64)p->result);
55 	return sizeof(u32);
56 }
57 
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_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 
108 static int __exit 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 
117 static struct platform_driver octeon_rng_driver = {
118 	.driver = {
119 		.name		= "octeon_rng",
120 	},
121 	.probe		= octeon_rng_probe,
122 	.remove		= __exit_p(octeon_rng_remove),
123 };
124 
125 module_platform_driver(octeon_rng_driver);
126 
127 MODULE_AUTHOR("David Daney");
128 MODULE_LICENSE("GPL");
129