drivers/char/hw_random/cavium-rng.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 #define THUNDERX_RNM_ENT_EN     0x1
  19 #define THUNDERX_RNM_RNG_EN     0x2
  20
  21 struct cavium_rng_pf {
  22         void __iomem *control_status;
  23 };
  24
  25 /* Enable the RNG hardware and activate the VF */
  26 static int cavium_rng_probe(struct pci_dev *pdev,
  27                         const struct pci_device_id *id)
  28 {
  29         struct  cavium_rng_pf *rng;
  30         int     iov_err;
  31
  32         rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL);
  33         if (!rng)
  34                 return -ENOMEM;
  35
  36         /*Map the RNG control */
  37         rng->control_status = pcim_iomap(pdev, 0, 0);
  38         if (!rng->control_status) {
  39                 dev_err(&pdev->dev,
  40                         "Error iomap failed retrieving control_status.\n");
  41                 return -ENOMEM;
  42         }
  43
  44         /* Enable the RNG hardware and entropy source */
  45         writeq(THUNDERX_RNM_RNG_EN | THUNDERX_RNM_ENT_EN,
  46                 rng->control_status);
  47
  48         pci_set_drvdata(pdev, rng);
  49
  50         /* Enable the Cavium RNG as a VF */
  51         iov_err = pci_enable_sriov(pdev, 1);
  52         if (iov_err != 0) {
  53                 /* Disable the RNG hardware and entropy source */
  54                 writeq(0, rng->control_status);
  55                 dev_err(&pdev->dev,
  56                         "Error initializing RNG virtual function,(%i).\n",
  57                         iov_err);
  58                 return iov_err;
  59         }
  60
  61         return 0;
  62 }
  63
  64 /* Disable VF and RNG Hardware */
  65 static void cavium_rng_remove(struct pci_dev *pdev)
  66 {
  67         struct cavium_rng_pf *rng;
  68
  69         rng = pci_get_drvdata(pdev);
  70
  71         /* Remove the VF */
  72         pci_disable_sriov(pdev);
  73
  74         /* Disable the RNG hardware and entropy source */
  75         writeq(0, rng->control_status);
  76 }
  77
  78 static const struct pci_device_id cavium_rng_pf_id_table[] = {
  79         { PCI_DEVICE(PCI_VENDOR_ID_CAVIUM, 0xa018), 0, 0, 0}, /* Thunder RNM */
  80         {0,},
  81 };
  82
  83 MODULE_DEVICE_TABLE(pci, cavium_rng_pf_id_table);
  84
  85 static struct pci_driver cavium_rng_pf_driver = {
  86         .name           = "cavium_rng_pf",
  87         .id_table       = cavium_rng_pf_id_table,
  88         .probe          = cavium_rng_probe,
  89         .remove         = cavium_rng_remove,
  90 };
  91
  92 module_pci_driver(cavium_rng_pf_driver);
  93 MODULE_AUTHOR("Omer Khaliq <okhaliq@caviumnetworks.com>");
  94 MODULE_LICENSE("GPL");