1// SPDX-License-Identifier: GPL-2.0
2/*
3 * PCI Backend - Handle special overlays for broken devices.
4 *
5 * Author: Ryan Wilson <hap9@epoch.ncsc.mil>
6 * Author: Chris Bookholt <hap10@epoch.ncsc.mil>
7 */
8
9#define dev_fmt(fmt) DRV_NAME ": " fmt
10
11#include <linux/kernel.h>
12#include <linux/pci.h>
13#include "pciback.h"
14#include "conf_space.h"
15#include "conf_space_quirks.h"
16
17LIST_HEAD(xen_pcibk_quirks);
18static inline const struct pci_device_id *
19match_one_device(const struct pci_device_id *id, const struct pci_dev *dev)
20{
21	if ((id->vendor == PCI_ANY_ID || id->vendor == dev->vendor) &&
22	    (id->device == PCI_ANY_ID || id->device == dev->device) &&
23	    (id->subvendor == PCI_ANY_ID ||
24				id->subvendor == dev->subsystem_vendor) &&
25	    (id->subdevice == PCI_ANY_ID ||
26				id->subdevice == dev->subsystem_device) &&
27	    !((id->class ^ dev->class) & id->class_mask))
28		return id;
29	return NULL;
30}
31
32static struct xen_pcibk_config_quirk *xen_pcibk_find_quirk(struct pci_dev *dev)
33{
34	struct xen_pcibk_config_quirk *tmp_quirk;
35
36	list_for_each_entry(tmp_quirk, &xen_pcibk_quirks, quirks_list)
37		if (match_one_device(&tmp_quirk->devid, dev) != NULL)
38			goto out;
39	tmp_quirk = NULL;
40	dev_printk(KERN_DEBUG, &dev->dev,
41		   "quirk didn't match any device known\n");
42out:
43	return tmp_quirk;
44}
45
46static inline void register_quirk(struct xen_pcibk_config_quirk *quirk)
47{
48	list_add_tail(&quirk->quirks_list, &xen_pcibk_quirks);
49}
50
51int xen_pcibk_field_is_dup(struct pci_dev *dev, unsigned int reg)
52{
53	int ret = 0;
54	struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
55	struct config_field_entry *cfg_entry;
56
57	list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {
58		if (OFFSET(cfg_entry) == reg) {
59			ret = 1;
60			break;
61		}
62	}
63	return ret;
64}
65
66int xen_pcibk_config_quirks_add_field(struct pci_dev *dev, struct config_field
67				    *field)
68{
69	int err = 0;
70
71	switch (field->size) {
72	case 1:
73		field->u.b.read = xen_pcibk_read_config_byte;
74		field->u.b.write = xen_pcibk_write_config_byte;
75		break;
76	case 2:
77		field->u.w.read = xen_pcibk_read_config_word;
78		field->u.w.write = xen_pcibk_write_config_word;
79		break;
80	case 4:
81		field->u.dw.read = xen_pcibk_read_config_dword;
82		field->u.dw.write = xen_pcibk_write_config_dword;
83		break;
84	default:
85		err = -EINVAL;
86		goto out;
87	}
88
89	xen_pcibk_config_add_field(dev, field);
90
91out:
92	return err;
93}
94
95int xen_pcibk_config_quirks_init(struct pci_dev *dev)
96{
97	struct xen_pcibk_config_quirk *quirk;
98	int ret = 0;
99
100	quirk = kzalloc(sizeof(*quirk), GFP_KERNEL);
101	if (!quirk) {
102		ret = -ENOMEM;
103		goto out;
104	}
105
106	quirk->devid.vendor = dev->vendor;
107	quirk->devid.device = dev->device;
108	quirk->devid.subvendor = dev->subsystem_vendor;
109	quirk->devid.subdevice = dev->subsystem_device;
110	quirk->devid.class = 0;
111	quirk->devid.class_mask = 0;
112	quirk->devid.driver_data = 0UL;
113
114	quirk->pdev = dev;
115
116	register_quirk(quirk);
117out:
118	return ret;
119}
120
121void xen_pcibk_config_field_free(struct config_field *field)
122{
123	kfree(field);
124}
125
126int xen_pcibk_config_quirk_release(struct pci_dev *dev)
127{
128	struct xen_pcibk_config_quirk *quirk;
129	int ret = 0;
130
131	quirk = xen_pcibk_find_quirk(dev);
132	if (!quirk) {
133		ret = -ENXIO;
134		goto out;
135	}
136
137	list_del(&quirk->quirks_list);
138	kfree(quirk);
139
140out:
141	return ret;
142}
143