1// SPDX-License-Identifier: GPL-2.0
2#include <linux/sched.h>
3#include <linux/mm.h>
4#include <linux/uaccess.h>
5#include <linux/mmzone.h>
6#include <linux/ioport.h>
7#include <linux/seq_file.h>
8#include <linux/console.h>
9#include <linux/init.h>
10#include <linux/edd.h>
11#include <linux/dmi.h>
12#include <linux/pfn.h>
13#include <linux/pci.h>
14#include <linux/export.h>
15
16#include <asm/probe_roms.h>
17#include <asm/pci-direct.h>
18#include <asm/e820/api.h>
19#include <asm/mmzone.h>
20#include <asm/setup.h>
21#include <asm/sections.h>
22#include <asm/io.h>
23#include <asm/setup_arch.h>
24#include <asm/sev.h>
25
26static struct resource system_rom_resource = {
27	.name	= "System ROM",
28	.start	= 0xf0000,
29	.end	= 0xfffff,
30	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
31};
32
33static struct resource extension_rom_resource = {
34	.name	= "Extension ROM",
35	.start	= 0xe0000,
36	.end	= 0xeffff,
37	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
38};
39
40static struct resource adapter_rom_resources[] = { {
41	.name 	= "Adapter ROM",
42	.start	= 0xc8000,
43	.end	= 0,
44	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
45}, {
46	.name 	= "Adapter ROM",
47	.start	= 0,
48	.end	= 0,
49	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
50}, {
51	.name 	= "Adapter ROM",
52	.start	= 0,
53	.end	= 0,
54	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
55}, {
56	.name 	= "Adapter ROM",
57	.start	= 0,
58	.end	= 0,
59	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
60}, {
61	.name 	= "Adapter ROM",
62	.start	= 0,
63	.end	= 0,
64	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
65}, {
66	.name 	= "Adapter ROM",
67	.start	= 0,
68	.end	= 0,
69	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
70} };
71
72static struct resource video_rom_resource = {
73	.name 	= "Video ROM",
74	.start	= 0xc0000,
75	.end	= 0xc7fff,
76	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
77};
78
79/* does this oprom support the given pci device, or any of the devices
80 * that the driver supports?
81 */
82static bool match_id(struct pci_dev *pdev, unsigned short vendor, unsigned short device)
83{
84	struct pci_driver *drv = to_pci_driver(pdev->dev.driver);
85	const struct pci_device_id *id;
86
87	if (pdev->vendor == vendor && pdev->device == device)
88		return true;
89
90	for (id = drv ? drv->id_table : NULL; id && id->vendor; id++)
91		if (id->vendor == vendor && id->device == device)
92			break;
93
94	return id && id->vendor;
95}
96
97static bool probe_list(struct pci_dev *pdev, unsigned short vendor,
98		       const void *rom_list)
99{
100	unsigned short device;
101
102	do {
103		if (get_kernel_nofault(device, rom_list) != 0)
104			device = 0;
105
106		if (device && match_id(pdev, vendor, device))
107			break;
108
109		rom_list += 2;
110	} while (device);
111
112	return !!device;
113}
114
115static struct resource *find_oprom(struct pci_dev *pdev)
116{
117	struct resource *oprom = NULL;
118	int i;
119
120	for (i = 0; i < ARRAY_SIZE(adapter_rom_resources); i++) {
121		struct resource *res = &adapter_rom_resources[i];
122		unsigned short offset, vendor, device, list, rev;
123		const void *rom;
124
125		if (res->end == 0)
126			break;
127
128		rom = isa_bus_to_virt(res->start);
129		if (get_kernel_nofault(offset, rom + 0x18) != 0)
130			continue;
131
132		if (get_kernel_nofault(vendor, rom + offset + 0x4) != 0)
133			continue;
134
135		if (get_kernel_nofault(device, rom + offset + 0x6) != 0)
136			continue;
137
138		if (match_id(pdev, vendor, device)) {
139			oprom = res;
140			break;
141		}
142
143		if (get_kernel_nofault(list, rom + offset + 0x8) == 0 &&
144		    get_kernel_nofault(rev, rom + offset + 0xc) == 0 &&
145		    rev >= 3 && list &&
146		    probe_list(pdev, vendor, rom + offset + list)) {
147			oprom = res;
148			break;
149		}
150	}
151
152	return oprom;
153}
154
155void __iomem *pci_map_biosrom(struct pci_dev *pdev)
156{
157	struct resource *oprom = find_oprom(pdev);
158
159	if (!oprom)
160		return NULL;
161
162	return ioremap(oprom->start, resource_size(oprom));
163}
164EXPORT_SYMBOL(pci_map_biosrom);
165
166void pci_unmap_biosrom(void __iomem *image)
167{
168	iounmap(image);
169}
170EXPORT_SYMBOL(pci_unmap_biosrom);
171
172size_t pci_biosrom_size(struct pci_dev *pdev)
173{
174	struct resource *oprom = find_oprom(pdev);
175
176	return oprom ? resource_size(oprom) : 0;
177}
178EXPORT_SYMBOL(pci_biosrom_size);
179
180#define ROMSIGNATURE 0xaa55
181
182static int __init romsignature(const unsigned char *rom)
183{
184	const unsigned short * const ptr = (const unsigned short *)rom;
185	unsigned short sig;
186
187	return get_kernel_nofault(sig, ptr) == 0 && sig == ROMSIGNATURE;
188}
189
190static int __init romchecksum(const unsigned char *rom, unsigned long length)
191{
192	unsigned char sum, c;
193
194	for (sum = 0; length && get_kernel_nofault(c, rom++) == 0; length--)
195		sum += c;
196	return !length && !sum;
197}
198
199void __init probe_roms(void)
200{
201	unsigned long start, length, upper;
202	const unsigned char *rom;
203	unsigned char c;
204	int i;
205
206	/* video rom */
207	upper = adapter_rom_resources[0].start;
208	for (start = video_rom_resource.start; start < upper; start += 2048) {
209		rom = isa_bus_to_virt(start);
210		if (!romsignature(rom))
211			continue;
212
213		video_rom_resource.start = start;
214
215		if (get_kernel_nofault(c, rom + 2) != 0)
216			continue;
217
218		/* 0 < length <= 0x7f * 512, historically */
219		length = c * 512;
220
221		/* if checksum okay, trust length byte */
222		if (length && romchecksum(rom, length))
223			video_rom_resource.end = start + length - 1;
224
225		request_resource(&iomem_resource, &video_rom_resource);
226		break;
227	}
228
229	start = (video_rom_resource.end + 1 + 2047) & ~2047UL;
230	if (start < upper)
231		start = upper;
232
233	/* system rom */
234	request_resource(&iomem_resource, &system_rom_resource);
235	upper = system_rom_resource.start;
236
237	/* check for extension rom (ignore length byte!) */
238	rom = isa_bus_to_virt(extension_rom_resource.start);
239	if (romsignature(rom)) {
240		length = resource_size(&extension_rom_resource);
241		if (romchecksum(rom, length)) {
242			request_resource(&iomem_resource, &extension_rom_resource);
243			upper = extension_rom_resource.start;
244		}
245	}
246
247	/* check for adapter roms on 2k boundaries */
248	for (i = 0; i < ARRAY_SIZE(adapter_rom_resources) && start < upper; start += 2048) {
249		rom = isa_bus_to_virt(start);
250		if (!romsignature(rom))
251			continue;
252
253		if (get_kernel_nofault(c, rom + 2) != 0)
254			continue;
255
256		/* 0 < length <= 0x7f * 512, historically */
257		length = c * 512;
258
259		/* but accept any length that fits if checksum okay */
260		if (!length || start + length > upper || !romchecksum(rom, length))
261			continue;
262
263		adapter_rom_resources[i].start = start;
264		adapter_rom_resources[i].end = start + length - 1;
265		request_resource(&iomem_resource, &adapter_rom_resources[i]);
266
267		start = adapter_rom_resources[i++].end & ~2047UL;
268	}
269}
270
271