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