LXR linux/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
  18struct cavium_rng {
  19        struct hwrng ops;
  20        void __iomem *result;
  21};
  22
  23/* Read data from the RNG unit */
  24static 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 */
  43static 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
  80static const struct pci_device_id cavium_rng_vf_id_table[] = {
  81        { PCI_DEVICE(PCI_VENDOR_ID_CAVIUM, 0xa033), 0, 0, 0},
  82        {0,},
  83};
  84MODULE_DEVICE_TABLE(pci, cavium_rng_vf_id_table);
  85
  86static 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};
  91module_pci_driver(cavium_rng_vf_driver);
  92
  93MODULE_AUTHOR("Omer Khaliq <okhaliq@caviumnetworks.com>");
  94MODULE_LICENSE("GPL");
  95