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 */
cavium_rng_probe(struct pci_dev * pdev,const struct pci_device_id * id)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 */
cavium_rng_remove(struct pci_dev * pdev)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_LICENSE("GPL v2");
92