Merge tag 'for-linus-5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw...
[linux-2.6-microblaze.git] / drivers / char / hw_random / octeon-rng.c
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((__force 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((__force 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((__force 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(&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");