drivers/char/hw_random/cavium-rng-vf.c

   1 /*
   2  * Hardware Random Number Generator support for Cavium, Inc.
   3  * Thunder 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) 2016 Cavium, Inc.
  10  */
  11
  12 #include <linux/hw_random.h>
  13 #include <linux/io.h>
  14 #include <linux/module.h>
  15 #include <linux/pci.h>
  16 #include <linux/pci_ids.h>
  17
  18 struct cavium_rng {
  19         struct hwrng ops;
  20         void __iomem *result;
  21 };
  22
  23 /* Read data from the RNG unit */
  24 static int cavium_rng_read(struct hwrng *rng, void *dat, size_t max, bool wait)
  25 {
  26         struct cavium_rng *p = container_of(rng, struct cavium_rng, ops);
  27         unsigned int size = max;
  28
  29         while (size >= 8) {
  30                 *((u64 *)dat) = readq(p->result);
  31                 size -= 8;
  32                 dat += 8;
  33         }
  34         while (size > 0) {
  35                 *((u8 *)dat) = readb(p->result);
  36                 size--;
  37                 dat++;
  38         }
  39         return max;
  40 }
  41
  42 /* Map Cavium RNG to an HWRNG object */
  43 static int cavium_rng_probe_vf(struct   pci_dev         *pdev,
  44                          const struct   pci_device_id   *id)
  45 {
  46         struct  cavium_rng *rng;
  47         int     ret;
  48
  49         rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL);
  50         if (!rng)
  51                 return -ENOMEM;
  52
  53         /* Map the RNG result */
  54         rng->result = pcim_iomap(pdev, 0, 0);
  55         if (!rng->result) {
  56                 dev_err(&pdev->dev, "Error iomap failed retrieving result.\n");
  57                 return -ENOMEM;
  58         }
  59
  60         rng->ops.name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
  61                                        "cavium-rng-%s", dev_name(&pdev->dev));
  62         if (!rng->ops.name)
  63                 return -ENOMEM;
  64
  65         rng->ops.read    = cavium_rng_read;
  66         rng->ops.quality = 1000;
  67
  68         pci_set_drvdata(pdev, rng);
  69
  70         ret = devm_hwrng_register(&pdev->dev, &rng->ops);
  71         if (ret) {
  72                 dev_err(&pdev->dev, "Error registering device as HWRNG.\n");
  73                 return ret;
  74         }
  75
  76         return 0;
  77 }
  78
  79
  80 static const struct pci_device_id cavium_rng_vf_id_table[] = {
  81         { PCI_DEVICE(PCI_VENDOR_ID_CAVIUM, 0xa033), 0, 0, 0},
  82         {0,},
  83 };
  84 MODULE_DEVICE_TABLE(pci, cavium_rng_vf_id_table);
  85
  86 static struct pci_driver cavium_rng_vf_driver = {
  87         .name           = "cavium_rng_vf",
  88         .id_table       = cavium_rng_vf_id_table,
  89         .probe          = cavium_rng_probe_vf,
  90 };
  91 module_pci_driver(cavium_rng_vf_driver);
  92
  93 MODULE_AUTHOR("Omer Khaliq <okhaliq@caviumnetworks.com>");
  94 MODULE_LICENSE("GPL");