xref: /linux/arch/x86/kernel/amd_nb.c (revision 23c996fc2bc1978a02c64eddb90b4ab5d309c8df)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Shared support code for AMD K8 northbridges and derivatives.
4  * Copyright 2006 Andi Kleen, SUSE Labs.
5  */
6 
7 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8 
9 #include <linux/types.h>
10 #include <linux/slab.h>
11 #include <linux/init.h>
12 #include <linux/errno.h>
13 #include <linux/export.h>
14 #include <linux/spinlock.h>
15 #include <linux/pci_ids.h>
16 #include <asm/amd_nb.h>
17 
18 #define PCI_DEVICE_ID_AMD_17H_ROOT		0x1450
19 #define PCI_DEVICE_ID_AMD_17H_M10H_ROOT		0x15d0
20 #define PCI_DEVICE_ID_AMD_17H_M30H_ROOT		0x1480
21 #define PCI_DEVICE_ID_AMD_17H_M60H_ROOT		0x1630
22 #define PCI_DEVICE_ID_AMD_17H_MA0H_ROOT		0x14b5
23 #define PCI_DEVICE_ID_AMD_19H_M10H_ROOT		0x14a4
24 #define PCI_DEVICE_ID_AMD_19H_M40H_ROOT		0x14b5
25 #define PCI_DEVICE_ID_AMD_19H_M60H_ROOT		0x14d8
26 #define PCI_DEVICE_ID_AMD_19H_M70H_ROOT		0x14e8
27 #define PCI_DEVICE_ID_AMD_1AH_M00H_ROOT		0x153a
28 #define PCI_DEVICE_ID_AMD_1AH_M20H_ROOT		0x1507
29 #define PCI_DEVICE_ID_AMD_MI200_ROOT		0x14bb
30 #define PCI_DEVICE_ID_AMD_MI300_ROOT		0x14f8
31 
32 #define PCI_DEVICE_ID_AMD_17H_DF_F4		0x1464
33 #define PCI_DEVICE_ID_AMD_17H_M10H_DF_F4	0x15ec
34 #define PCI_DEVICE_ID_AMD_17H_M30H_DF_F4	0x1494
35 #define PCI_DEVICE_ID_AMD_17H_M60H_DF_F4	0x144c
36 #define PCI_DEVICE_ID_AMD_17H_M70H_DF_F4	0x1444
37 #define PCI_DEVICE_ID_AMD_17H_MA0H_DF_F4	0x1728
38 #define PCI_DEVICE_ID_AMD_19H_DF_F4		0x1654
39 #define PCI_DEVICE_ID_AMD_19H_M10H_DF_F4	0x14b1
40 #define PCI_DEVICE_ID_AMD_19H_M40H_DF_F4	0x167d
41 #define PCI_DEVICE_ID_AMD_19H_M50H_DF_F4	0x166e
42 #define PCI_DEVICE_ID_AMD_19H_M60H_DF_F4	0x14e4
43 #define PCI_DEVICE_ID_AMD_19H_M70H_DF_F4	0x14f4
44 #define PCI_DEVICE_ID_AMD_19H_M78H_DF_F4	0x12fc
45 #define PCI_DEVICE_ID_AMD_1AH_M00H_DF_F4	0x12c4
46 #define PCI_DEVICE_ID_AMD_MI200_DF_F4		0x14d4
47 #define PCI_DEVICE_ID_AMD_MI300_DF_F4		0x152c
48 
49 /* Protect the PCI config register pairs used for SMN. */
50 static DEFINE_MUTEX(smn_mutex);
51 
52 static u32 *flush_words;
53 
54 static const struct pci_device_id amd_root_ids[] = {
55 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_ROOT) },
56 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M10H_ROOT) },
57 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M30H_ROOT) },
58 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M60H_ROOT) },
59 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_MA0H_ROOT) },
60 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M10H_ROOT) },
61 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M40H_ROOT) },
62 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M60H_ROOT) },
63 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M70H_ROOT) },
64 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_1AH_M00H_ROOT) },
65 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_1AH_M20H_ROOT) },
66 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_MI200_ROOT) },
67 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_MI300_ROOT) },
68 	{}
69 };
70 
71 #define PCI_DEVICE_ID_AMD_CNB17H_F4     0x1704
72 
73 static const struct pci_device_id amd_nb_misc_ids[] = {
74 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_K8_NB_MISC) },
75 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_10H_NB_MISC) },
76 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_NB_F3) },
77 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_M10H_F3) },
78 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_M30H_NB_F3) },
79 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_M60H_NB_F3) },
80 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_16H_NB_F3) },
81 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_16H_M30H_NB_F3) },
82 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_DF_F3) },
83 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M10H_DF_F3) },
84 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M30H_DF_F3) },
85 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M60H_DF_F3) },
86 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_MA0H_DF_F3) },
87 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_CNB17H_F3) },
88 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M70H_DF_F3) },
89 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_DF_F3) },
90 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M10H_DF_F3) },
91 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M40H_DF_F3) },
92 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M50H_DF_F3) },
93 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M60H_DF_F3) },
94 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M70H_DF_F3) },
95 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M78H_DF_F3) },
96 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_1AH_M00H_DF_F3) },
97 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_1AH_M20H_DF_F3) },
98 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_1AH_M70H_DF_F3) },
99 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_MI200_DF_F3) },
100 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_MI300_DF_F3) },
101 	{}
102 };
103 
104 static const struct pci_device_id amd_nb_link_ids[] = {
105 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_NB_F4) },
106 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_M30H_NB_F4) },
107 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_M60H_NB_F4) },
108 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_16H_NB_F4) },
109 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_16H_M30H_NB_F4) },
110 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_DF_F4) },
111 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M10H_DF_F4) },
112 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M30H_DF_F4) },
113 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M60H_DF_F4) },
114 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M70H_DF_F4) },
115 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_MA0H_DF_F4) },
116 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_DF_F4) },
117 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M10H_DF_F4) },
118 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M40H_DF_F4) },
119 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M50H_DF_F4) },
120 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M60H_DF_F4) },
121 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M70H_DF_F4) },
122 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M78H_DF_F4) },
123 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_CNB17H_F4) },
124 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_1AH_M00H_DF_F4) },
125 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_MI200_DF_F4) },
126 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_MI300_DF_F4) },
127 	{}
128 };
129 
130 static const struct pci_device_id hygon_root_ids[] = {
131 	{ PCI_DEVICE(PCI_VENDOR_ID_HYGON, PCI_DEVICE_ID_AMD_17H_ROOT) },
132 	{}
133 };
134 
135 static const struct pci_device_id hygon_nb_misc_ids[] = {
136 	{ PCI_DEVICE(PCI_VENDOR_ID_HYGON, PCI_DEVICE_ID_AMD_17H_DF_F3) },
137 	{}
138 };
139 
140 static const struct pci_device_id hygon_nb_link_ids[] = {
141 	{ PCI_DEVICE(PCI_VENDOR_ID_HYGON, PCI_DEVICE_ID_AMD_17H_DF_F4) },
142 	{}
143 };
144 
145 const struct amd_nb_bus_dev_range amd_nb_bus_dev_ranges[] __initconst = {
146 	{ 0x00, 0x18, 0x20 },
147 	{ 0xff, 0x00, 0x20 },
148 	{ 0xfe, 0x00, 0x20 },
149 	{ }
150 };
151 
152 static struct amd_northbridge_info amd_northbridges;
153 
154 u16 amd_nb_num(void)
155 {
156 	return amd_northbridges.num;
157 }
158 EXPORT_SYMBOL_GPL(amd_nb_num);
159 
160 bool amd_nb_has_feature(unsigned int feature)
161 {
162 	return ((amd_northbridges.flags & feature) == feature);
163 }
164 EXPORT_SYMBOL_GPL(amd_nb_has_feature);
165 
166 struct amd_northbridge *node_to_amd_nb(int node)
167 {
168 	return (node < amd_northbridges.num) ? &amd_northbridges.nb[node] : NULL;
169 }
170 EXPORT_SYMBOL_GPL(node_to_amd_nb);
171 
172 static struct pci_dev *next_northbridge(struct pci_dev *dev,
173 					const struct pci_device_id *ids)
174 {
175 	do {
176 		dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev);
177 		if (!dev)
178 			break;
179 	} while (!pci_match_id(ids, dev));
180 	return dev;
181 }
182 
183 static int __amd_smn_rw(u16 node, u32 address, u32 *value, bool write)
184 {
185 	struct pci_dev *root;
186 	int err = -ENODEV;
187 
188 	if (node >= amd_northbridges.num)
189 		goto out;
190 
191 	root = node_to_amd_nb(node)->root;
192 	if (!root)
193 		goto out;
194 
195 	mutex_lock(&smn_mutex);
196 
197 	err = pci_write_config_dword(root, 0x60, address);
198 	if (err) {
199 		pr_warn("Error programming SMN address 0x%x.\n", address);
200 		goto out_unlock;
201 	}
202 
203 	err = (write ? pci_write_config_dword(root, 0x64, *value)
204 		     : pci_read_config_dword(root, 0x64, value));
205 	if (err)
206 		pr_warn("Error %s SMN address 0x%x.\n",
207 			(write ? "writing to" : "reading from"), address);
208 
209 out_unlock:
210 	mutex_unlock(&smn_mutex);
211 
212 out:
213 	return err;
214 }
215 
216 int amd_smn_read(u16 node, u32 address, u32 *value)
217 {
218 	return __amd_smn_rw(node, address, value, false);
219 }
220 EXPORT_SYMBOL_GPL(amd_smn_read);
221 
222 int amd_smn_write(u16 node, u32 address, u32 value)
223 {
224 	return __amd_smn_rw(node, address, &value, true);
225 }
226 EXPORT_SYMBOL_GPL(amd_smn_write);
227 
228 
229 static int amd_cache_northbridges(void)
230 {
231 	const struct pci_device_id *misc_ids = amd_nb_misc_ids;
232 	const struct pci_device_id *link_ids = amd_nb_link_ids;
233 	const struct pci_device_id *root_ids = amd_root_ids;
234 	struct pci_dev *root, *misc, *link;
235 	struct amd_northbridge *nb;
236 	u16 roots_per_misc = 0;
237 	u16 misc_count = 0;
238 	u16 root_count = 0;
239 	u16 i, j;
240 
241 	if (amd_northbridges.num)
242 		return 0;
243 
244 	if (boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) {
245 		root_ids = hygon_root_ids;
246 		misc_ids = hygon_nb_misc_ids;
247 		link_ids = hygon_nb_link_ids;
248 	}
249 
250 	misc = NULL;
251 	while ((misc = next_northbridge(misc, misc_ids)))
252 		misc_count++;
253 
254 	if (!misc_count)
255 		return -ENODEV;
256 
257 	root = NULL;
258 	while ((root = next_northbridge(root, root_ids)))
259 		root_count++;
260 
261 	if (root_count) {
262 		roots_per_misc = root_count / misc_count;
263 
264 		/*
265 		 * There should be _exactly_ N roots for each DF/SMN
266 		 * interface.
267 		 */
268 		if (!roots_per_misc || (root_count % roots_per_misc)) {
269 			pr_info("Unsupported AMD DF/PCI configuration found\n");
270 			return -ENODEV;
271 		}
272 	}
273 
274 	nb = kcalloc(misc_count, sizeof(struct amd_northbridge), GFP_KERNEL);
275 	if (!nb)
276 		return -ENOMEM;
277 
278 	amd_northbridges.nb = nb;
279 	amd_northbridges.num = misc_count;
280 
281 	link = misc = root = NULL;
282 	for (i = 0; i < amd_northbridges.num; i++) {
283 		node_to_amd_nb(i)->root = root =
284 			next_northbridge(root, root_ids);
285 		node_to_amd_nb(i)->misc = misc =
286 			next_northbridge(misc, misc_ids);
287 		node_to_amd_nb(i)->link = link =
288 			next_northbridge(link, link_ids);
289 
290 		/*
291 		 * If there are more PCI root devices than data fabric/
292 		 * system management network interfaces, then the (N)
293 		 * PCI roots per DF/SMN interface are functionally the
294 		 * same (for DF/SMN access) and N-1 are redundant.  N-1
295 		 * PCI roots should be skipped per DF/SMN interface so
296 		 * the following DF/SMN interfaces get mapped to
297 		 * correct PCI roots.
298 		 */
299 		for (j = 1; j < roots_per_misc; j++)
300 			root = next_northbridge(root, root_ids);
301 	}
302 
303 	if (amd_gart_present())
304 		amd_northbridges.flags |= AMD_NB_GART;
305 
306 	/*
307 	 * Check for L3 cache presence.
308 	 */
309 	if (!cpuid_edx(0x80000006))
310 		return 0;
311 
312 	/*
313 	 * Some CPU families support L3 Cache Index Disable. There are some
314 	 * limitations because of E382 and E388 on family 0x10.
315 	 */
316 	if (boot_cpu_data.x86 == 0x10 &&
317 	    boot_cpu_data.x86_model >= 0x8 &&
318 	    (boot_cpu_data.x86_model > 0x9 ||
319 	     boot_cpu_data.x86_stepping >= 0x1))
320 		amd_northbridges.flags |= AMD_NB_L3_INDEX_DISABLE;
321 
322 	if (boot_cpu_data.x86 == 0x15)
323 		amd_northbridges.flags |= AMD_NB_L3_INDEX_DISABLE;
324 
325 	/* L3 cache partitioning is supported on family 0x15 */
326 	if (boot_cpu_data.x86 == 0x15)
327 		amd_northbridges.flags |= AMD_NB_L3_PARTITIONING;
328 
329 	return 0;
330 }
331 
332 /*
333  * Ignores subdevice/subvendor but as far as I can figure out
334  * they're useless anyways
335  */
336 bool __init early_is_amd_nb(u32 device)
337 {
338 	const struct pci_device_id *misc_ids = amd_nb_misc_ids;
339 	const struct pci_device_id *id;
340 	u32 vendor = device & 0xffff;
341 
342 	if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD &&
343 	    boot_cpu_data.x86_vendor != X86_VENDOR_HYGON)
344 		return false;
345 
346 	if (boot_cpu_data.x86_vendor == X86_VENDOR_HYGON)
347 		misc_ids = hygon_nb_misc_ids;
348 
349 	device >>= 16;
350 	for (id = misc_ids; id->vendor; id++)
351 		if (vendor == id->vendor && device == id->device)
352 			return true;
353 	return false;
354 }
355 
356 struct resource *amd_get_mmconfig_range(struct resource *res)
357 {
358 	u32 address;
359 	u64 base, msr;
360 	unsigned int segn_busn_bits;
361 
362 	if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD &&
363 	    boot_cpu_data.x86_vendor != X86_VENDOR_HYGON)
364 		return NULL;
365 
366 	/* assume all cpus from fam10h have mmconfig */
367 	if (boot_cpu_data.x86 < 0x10)
368 		return NULL;
369 
370 	address = MSR_FAM10H_MMIO_CONF_BASE;
371 	rdmsrl(address, msr);
372 
373 	/* mmconfig is not enabled */
374 	if (!(msr & FAM10H_MMIO_CONF_ENABLE))
375 		return NULL;
376 
377 	base = msr & (FAM10H_MMIO_CONF_BASE_MASK<<FAM10H_MMIO_CONF_BASE_SHIFT);
378 
379 	segn_busn_bits = (msr >> FAM10H_MMIO_CONF_BUSRANGE_SHIFT) &
380 			 FAM10H_MMIO_CONF_BUSRANGE_MASK;
381 
382 	res->flags = IORESOURCE_MEM;
383 	res->start = base;
384 	res->end = base + (1ULL<<(segn_busn_bits + 20)) - 1;
385 	return res;
386 }
387 
388 int amd_get_subcaches(int cpu)
389 {
390 	struct pci_dev *link = node_to_amd_nb(topology_amd_node_id(cpu))->link;
391 	unsigned int mask;
392 
393 	if (!amd_nb_has_feature(AMD_NB_L3_PARTITIONING))
394 		return 0;
395 
396 	pci_read_config_dword(link, 0x1d4, &mask);
397 
398 	return (mask >> (4 * cpu_data(cpu).topo.core_id)) & 0xf;
399 }
400 
401 int amd_set_subcaches(int cpu, unsigned long mask)
402 {
403 	static unsigned int reset, ban;
404 	struct amd_northbridge *nb = node_to_amd_nb(topology_amd_node_id(cpu));
405 	unsigned int reg;
406 	int cuid;
407 
408 	if (!amd_nb_has_feature(AMD_NB_L3_PARTITIONING) || mask > 0xf)
409 		return -EINVAL;
410 
411 	/* if necessary, collect reset state of L3 partitioning and BAN mode */
412 	if (reset == 0) {
413 		pci_read_config_dword(nb->link, 0x1d4, &reset);
414 		pci_read_config_dword(nb->misc, 0x1b8, &ban);
415 		ban &= 0x180000;
416 	}
417 
418 	/* deactivate BAN mode if any subcaches are to be disabled */
419 	if (mask != 0xf) {
420 		pci_read_config_dword(nb->misc, 0x1b8, &reg);
421 		pci_write_config_dword(nb->misc, 0x1b8, reg & ~0x180000);
422 	}
423 
424 	cuid = cpu_data(cpu).topo.core_id;
425 	mask <<= 4 * cuid;
426 	mask |= (0xf ^ (1 << cuid)) << 26;
427 
428 	pci_write_config_dword(nb->link, 0x1d4, mask);
429 
430 	/* reset BAN mode if L3 partitioning returned to reset state */
431 	pci_read_config_dword(nb->link, 0x1d4, &reg);
432 	if (reg == reset) {
433 		pci_read_config_dword(nb->misc, 0x1b8, &reg);
434 		reg &= ~0x180000;
435 		pci_write_config_dword(nb->misc, 0x1b8, reg | ban);
436 	}
437 
438 	return 0;
439 }
440 
441 static void amd_cache_gart(void)
442 {
443 	u16 i;
444 
445 	if (!amd_nb_has_feature(AMD_NB_GART))
446 		return;
447 
448 	flush_words = kmalloc_array(amd_northbridges.num, sizeof(u32), GFP_KERNEL);
449 	if (!flush_words) {
450 		amd_northbridges.flags &= ~AMD_NB_GART;
451 		pr_notice("Cannot initialize GART flush words, GART support disabled\n");
452 		return;
453 	}
454 
455 	for (i = 0; i != amd_northbridges.num; i++)
456 		pci_read_config_dword(node_to_amd_nb(i)->misc, 0x9c, &flush_words[i]);
457 }
458 
459 void amd_flush_garts(void)
460 {
461 	int flushed, i;
462 	unsigned long flags;
463 	static DEFINE_SPINLOCK(gart_lock);
464 
465 	if (!amd_nb_has_feature(AMD_NB_GART))
466 		return;
467 
468 	/*
469 	 * Avoid races between AGP and IOMMU. In theory it's not needed
470 	 * but I'm not sure if the hardware won't lose flush requests
471 	 * when another is pending. This whole thing is so expensive anyways
472 	 * that it doesn't matter to serialize more. -AK
473 	 */
474 	spin_lock_irqsave(&gart_lock, flags);
475 	flushed = 0;
476 	for (i = 0; i < amd_northbridges.num; i++) {
477 		pci_write_config_dword(node_to_amd_nb(i)->misc, 0x9c,
478 				       flush_words[i] | 1);
479 		flushed++;
480 	}
481 	for (i = 0; i < amd_northbridges.num; i++) {
482 		u32 w;
483 		/* Make sure the hardware actually executed the flush*/
484 		for (;;) {
485 			pci_read_config_dword(node_to_amd_nb(i)->misc,
486 					      0x9c, &w);
487 			if (!(w & 1))
488 				break;
489 			cpu_relax();
490 		}
491 	}
492 	spin_unlock_irqrestore(&gart_lock, flags);
493 	if (!flushed)
494 		pr_notice("nothing to flush?\n");
495 }
496 EXPORT_SYMBOL_GPL(amd_flush_garts);
497 
498 static void __fix_erratum_688(void *info)
499 {
500 #define MSR_AMD64_IC_CFG 0xC0011021
501 
502 	msr_set_bit(MSR_AMD64_IC_CFG, 3);
503 	msr_set_bit(MSR_AMD64_IC_CFG, 14);
504 }
505 
506 /* Apply erratum 688 fix so machines without a BIOS fix work. */
507 static __init void fix_erratum_688(void)
508 {
509 	struct pci_dev *F4;
510 	u32 val;
511 
512 	if (boot_cpu_data.x86 != 0x14)
513 		return;
514 
515 	if (!amd_northbridges.num)
516 		return;
517 
518 	F4 = node_to_amd_nb(0)->link;
519 	if (!F4)
520 		return;
521 
522 	if (pci_read_config_dword(F4, 0x164, &val))
523 		return;
524 
525 	if (val & BIT(2))
526 		return;
527 
528 	on_each_cpu(__fix_erratum_688, NULL, 0);
529 
530 	pr_info("x86/cpu/AMD: CPU erratum 688 worked around\n");
531 }
532 
533 static __init int init_amd_nbs(void)
534 {
535 	amd_cache_northbridges();
536 	amd_cache_gart();
537 
538 	fix_erratum_688();
539 
540 	return 0;
541 }
542 
543 /* This has to go after the PCI subsystem */
544 fs_initcall(init_amd_nbs);
545