drivers/char/hw_random/cavium-rng.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Hardware Random Number Generator support.
   4  * Cavium Thunder, Marvell OcteonTx/Tx2 processor families.
   5  *
   6  * Copyright (C) 2016 Cavium, Inc.
   7  */
   8
   9 #include <linux/hw_random.h>
  10 #include <linux/io.h>
  11 #include <linux/module.h>
  12 #include <linux/pci.h>
  13 #include <linux/pci_ids.h>
  14
  15 #define THUNDERX_RNM_ENT_EN     0x1
  16 #define THUNDERX_RNM_RNG_EN     0x2
  17
  18 struct cavium_rng_pf {
  19         void __iomem *control_status;
  20 };
  21
  22 /* Enable the RNG hardware and activate the VF */
  23 static int cavium_rng_probe(struct pci_dev *pdev,
  24                         const struct pci_device_id *id)
  25 {
  26         struct  cavium_rng_pf *rng;
  27         int     iov_err;
  28
  29         rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL);
  30         if (!rng)
  31                 return -ENOMEM;
  32
  33         /*Map the RNG control */
  34         rng->control_status = pcim_iomap(pdev, 0, 0);
  35         if (!rng->control_status) {
  36                 dev_err(&pdev->dev,
  37                         "Error iomap failed retrieving control_status.\n");
  38                 return -ENOMEM;
  39         }
  40
  41         /* Enable the RNG hardware and entropy source */
  42         writeq(THUNDERX_RNM_RNG_EN | THUNDERX_RNM_ENT_EN,
  43                 rng->control_status);
  44
  45         pci_set_drvdata(pdev, rng);
  46
  47         /* Enable the Cavium RNG as a VF */
  48         iov_err = pci_enable_sriov(pdev, 1);
  49         if (iov_err != 0) {
  50                 /* Disable the RNG hardware and entropy source */
  51                 writeq(0, rng->control_status);
  52                 dev_err(&pdev->dev,
  53                         "Error initializing RNG virtual function,(%i).\n",
  54                         iov_err);
  55                 return iov_err;
  56         }
  57
  58         return 0;
  59 }
  60
  61 /* Disable VF and RNG Hardware */
  62 static void cavium_rng_remove(struct pci_dev *pdev)
  63 {
  64         struct cavium_rng_pf *rng;
  65
  66         rng = pci_get_drvdata(pdev);
  67
  68         /* Remove the VF */
  69         pci_disable_sriov(pdev);
  70
  71         /* Disable the RNG hardware and entropy source */
  72         writeq(0, rng->control_status);
  73 }
  74
  75 static const struct pci_device_id cavium_rng_pf_id_table[] = {
  76         { PCI_DEVICE(PCI_VENDOR_ID_CAVIUM, 0xa018), 0, 0, 0}, /* Thunder RNM */
  77         {0,},
  78 };
  79
  80 MODULE_DEVICE_TABLE(pci, cavium_rng_pf_id_table);
  81
  82 static struct pci_driver cavium_rng_pf_driver = {
  83         .name           = "cavium_rng_pf",
  84         .id_table       = cavium_rng_pf_id_table,
  85         .probe          = cavium_rng_probe,
  86         .remove         = cavium_rng_remove,
  87 };
  88
  89 module_pci_driver(cavium_rng_pf_driver);
  90 MODULE_AUTHOR("Omer Khaliq <okhaliq@caviumnetworks.com>");
  91 MODULE_DESCRIPTION("Cavium ThunderX Random Number Generator support");
  92 MODULE_LICENSE("GPL v2");