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 struct cavium_rng {
19 	struct hwrng ops;
20 	void __iomem *result;
21 };
22 
23 /* Read data from the RNG unit */
24 static 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 */
43 static 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 = hwrng_register(&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 /* Remove the VF */
80 static void  cavium_rng_remove_vf(struct pci_dev *pdev)
81 {
82 	struct cavium_rng *rng;
83 
84 	rng = pci_get_drvdata(pdev);
85 	hwrng_unregister(&rng->ops);
86 }
87 
88 static const struct pci_device_id cavium_rng_vf_id_table[] = {
89 	{ PCI_DEVICE(PCI_VENDOR_ID_CAVIUM, 0xa033), 0, 0, 0},
90 	{0,},
91 };
92 MODULE_DEVICE_TABLE(pci, cavium_rng_vf_id_table);
93 
94 static struct pci_driver cavium_rng_vf_driver = {
95 	.name		= "cavium_rng_vf",
96 	.id_table	= cavium_rng_vf_id_table,
97 	.probe		= cavium_rng_probe_vf,
98 	.remove		= cavium_rng_remove_vf,
99 };
100 module_pci_driver(cavium_rng_vf_driver);
101 
102 MODULE_AUTHOR("Omer Khaliq <okhaliq@caviumnetworks.com>");
103 MODULE_LICENSE("GPL");
104