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");
95