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