xref: /openbmc/linux/arch/x86/kernel/amd_nb.c (revision 9470114d)
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 
31 #define PCI_DEVICE_ID_AMD_17H_DF_F4		0x1464
32 #define PCI_DEVICE_ID_AMD_17H_M10H_DF_F4	0x15ec
33 #define PCI_DEVICE_ID_AMD_17H_M30H_DF_F4	0x1494
34 #define PCI_DEVICE_ID_AMD_17H_M60H_DF_F4	0x144c
35 #define PCI_DEVICE_ID_AMD_17H_M70H_DF_F4	0x1444
36 #define PCI_DEVICE_ID_AMD_17H_MA0H_DF_F4	0x1728
37 #define PCI_DEVICE_ID_AMD_19H_DF_F4		0x1654
38 #define PCI_DEVICE_ID_AMD_19H_M10H_DF_F4	0x14b1
39 #define PCI_DEVICE_ID_AMD_19H_M40H_DF_F4	0x167d
40 #define PCI_DEVICE_ID_AMD_19H_M50H_DF_F4	0x166e
41 #define PCI_DEVICE_ID_AMD_19H_M60H_DF_F4	0x14e4
42 #define PCI_DEVICE_ID_AMD_19H_M70H_DF_F4	0x14f4
43 #define PCI_DEVICE_ID_AMD_19H_M78H_DF_F4	0x12fc
44 #define PCI_DEVICE_ID_AMD_1AH_M00H_DF_F4	0x12c4
45 #define PCI_DEVICE_ID_AMD_MI200_DF_F4		0x14d4
46 
47 /* Protect the PCI config register pairs used for SMN. */
48 static DEFINE_MUTEX(smn_mutex);
49 
50 static u32 *flush_words;
51 
52 static const struct pci_device_id amd_root_ids[] = {
53 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_ROOT) },
54 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M10H_ROOT) },
55 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M30H_ROOT) },
56 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M60H_ROOT) },
57 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_MA0H_ROOT) },
58 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M10H_ROOT) },
59 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M40H_ROOT) },
60 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M60H_ROOT) },
61 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M70H_ROOT) },
62 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_1AH_M00H_ROOT) },
63 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_1AH_M20H_ROOT) },
64 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_MI200_ROOT) },
65 	{}
66 };
67 
68 #define PCI_DEVICE_ID_AMD_CNB17H_F4     0x1704
69 
70 static const struct pci_device_id amd_nb_misc_ids[] = {
71 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_K8_NB_MISC) },
72 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_10H_NB_MISC) },
73 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_NB_F3) },
74 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_M10H_F3) },
75 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_M30H_NB_F3) },
76 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_M60H_NB_F3) },
77 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_16H_NB_F3) },
78 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_16H_M30H_NB_F3) },
79 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_DF_F3) },
80 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M10H_DF_F3) },
81 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M30H_DF_F3) },
82 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M60H_DF_F3) },
83 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_MA0H_DF_F3) },
84 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_CNB17H_F3) },
85 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M70H_DF_F3) },
86 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_DF_F3) },
87 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M10H_DF_F3) },
88 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M40H_DF_F3) },
89 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M50H_DF_F3) },
90 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M60H_DF_F3) },
91 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M70H_DF_F3) },
92 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M78H_DF_F3) },
93 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_1AH_M00H_DF_F3) },
94 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_1AH_M20H_DF_F3) },
95 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_MI200_DF_F3) },
96 	{}
97 };
98 
99 static const struct pci_device_id amd_nb_link_ids[] = {
100 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_NB_F4) },
101 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_M30H_NB_F4) },
102 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_M60H_NB_F4) },
103 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_16H_NB_F4) },
104 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_16H_M30H_NB_F4) },
105 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_DF_F4) },
106 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M10H_DF_F4) },
107 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M30H_DF_F4) },
108 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M60H_DF_F4) },
109 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M70H_DF_F4) },
110 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_MA0H_DF_F4) },
111 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_DF_F4) },
112 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M10H_DF_F4) },
113 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M40H_DF_F4) },
114 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M50H_DF_F4) },
115 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M60H_DF_F4) },
116 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M70H_DF_F4) },
117 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M78H_DF_F4) },
118 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_CNB17H_F4) },
119 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_1AH_M00H_DF_F4) },
120 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_MI200_DF_F4) },
121 	{}
122 };
123 
124 static const struct pci_device_id hygon_root_ids[] = {
125 	{ PCI_DEVICE(PCI_VENDOR_ID_HYGON, PCI_DEVICE_ID_AMD_17H_ROOT) },
126 	{}
127 };
128 
129 static const struct pci_device_id hygon_nb_misc_ids[] = {
130 	{ PCI_DEVICE(PCI_VENDOR_ID_HYGON, PCI_DEVICE_ID_AMD_17H_DF_F3) },
131 	{}
132 };
133 
134 static const struct pci_device_id hygon_nb_link_ids[] = {
135 	{ PCI_DEVICE(PCI_VENDOR_ID_HYGON, PCI_DEVICE_ID_AMD_17H_DF_F4) },
136 	{}
137 };
138 
139 const struct amd_nb_bus_dev_range amd_nb_bus_dev_ranges[] __initconst = {
140 	{ 0x00, 0x18, 0x20 },
141 	{ 0xff, 0x00, 0x20 },
142 	{ 0xfe, 0x00, 0x20 },
143 	{ }
144 };
145 
146 static struct amd_northbridge_info amd_northbridges;
147 
148 u16 amd_nb_num(void)
149 {
150 	return amd_northbridges.num;
151 }
152 EXPORT_SYMBOL_GPL(amd_nb_num);
153 
154 bool amd_nb_has_feature(unsigned int feature)
155 {
156 	return ((amd_northbridges.flags & feature) == feature);
157 }
158 EXPORT_SYMBOL_GPL(amd_nb_has_feature);
159 
160 struct amd_northbridge *node_to_amd_nb(int node)
161 {
162 	return (node < amd_northbridges.num) ? &amd_northbridges.nb[node] : NULL;
163 }
164 EXPORT_SYMBOL_GPL(node_to_amd_nb);
165 
166 static struct pci_dev *next_northbridge(struct pci_dev *dev,
167 					const struct pci_device_id *ids)
168 {
169 	do {
170 		dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev);
171 		if (!dev)
172 			break;
173 	} while (!pci_match_id(ids, dev));
174 	return dev;
175 }
176 
177 static int __amd_smn_rw(u16 node, u32 address, u32 *value, bool write)
178 {
179 	struct pci_dev *root;
180 	int err = -ENODEV;
181 
182 	if (node >= amd_northbridges.num)
183 		goto out;
184 
185 	root = node_to_amd_nb(node)->root;
186 	if (!root)
187 		goto out;
188 
189 	mutex_lock(&smn_mutex);
190 
191 	err = pci_write_config_dword(root, 0x60, address);
192 	if (err) {
193 		pr_warn("Error programming SMN address 0x%x.\n", address);
194 		goto out_unlock;
195 	}
196 
197 	err = (write ? pci_write_config_dword(root, 0x64, *value)
198 		     : pci_read_config_dword(root, 0x64, value));
199 	if (err)
200 		pr_warn("Error %s SMN address 0x%x.\n",
201 			(write ? "writing to" : "reading from"), address);
202 
203 out_unlock:
204 	mutex_unlock(&smn_mutex);
205 
206 out:
207 	return err;
208 }
209 
210 int amd_smn_read(u16 node, u32 address, u32 *value)
211 {
212 	return __amd_smn_rw(node, address, value, false);
213 }
214 EXPORT_SYMBOL_GPL(amd_smn_read);
215 
216 int amd_smn_write(u16 node, u32 address, u32 value)
217 {
218 	return __amd_smn_rw(node, address, &value, true);
219 }
220 EXPORT_SYMBOL_GPL(amd_smn_write);
221 
222 
223 static int amd_cache_northbridges(void)
224 {
225 	const struct pci_device_id *misc_ids = amd_nb_misc_ids;
226 	const struct pci_device_id *link_ids = amd_nb_link_ids;
227 	const struct pci_device_id *root_ids = amd_root_ids;
228 	struct pci_dev *root, *misc, *link;
229 	struct amd_northbridge *nb;
230 	u16 roots_per_misc = 0;
231 	u16 misc_count = 0;
232 	u16 root_count = 0;
233 	u16 i, j;
234 
235 	if (amd_northbridges.num)
236 		return 0;
237 
238 	if (boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) {
239 		root_ids = hygon_root_ids;
240 		misc_ids = hygon_nb_misc_ids;
241 		link_ids = hygon_nb_link_ids;
242 	}
243 
244 	misc = NULL;
245 	while ((misc = next_northbridge(misc, misc_ids)))
246 		misc_count++;
247 
248 	if (!misc_count)
249 		return -ENODEV;
250 
251 	root = NULL;
252 	while ((root = next_northbridge(root, root_ids)))
253 		root_count++;
254 
255 	if (root_count) {
256 		roots_per_misc = root_count / misc_count;
257 
258 		/*
259 		 * There should be _exactly_ N roots for each DF/SMN
260 		 * interface.
261 		 */
262 		if (!roots_per_misc || (root_count % roots_per_misc)) {
263 			pr_info("Unsupported AMD DF/PCI configuration found\n");
264 			return -ENODEV;
265 		}
266 	}
267 
268 	nb = kcalloc(misc_count, sizeof(struct amd_northbridge), GFP_KERNEL);
269 	if (!nb)
270 		return -ENOMEM;
271 
272 	amd_northbridges.nb = nb;
273 	amd_northbridges.num = misc_count;
274 
275 	link = misc = root = NULL;
276 	for (i = 0; i < amd_northbridges.num; i++) {
277 		node_to_amd_nb(i)->root = root =
278 			next_northbridge(root, root_ids);
279 		node_to_amd_nb(i)->misc = misc =
280 			next_northbridge(misc, misc_ids);
281 		node_to_amd_nb(i)->link = link =
282 			next_northbridge(link, link_ids);
283 
284 		/*
285 		 * If there are more PCI root devices than data fabric/
286 		 * system management network interfaces, then the (N)
287 		 * PCI roots per DF/SMN interface are functionally the
288 		 * same (for DF/SMN access) and N-1 are redundant.  N-1
289 		 * PCI roots should be skipped per DF/SMN interface so
290 		 * the following DF/SMN interfaces get mapped to
291 		 * correct PCI roots.
292 		 */
293 		for (j = 1; j < roots_per_misc; j++)
294 			root = next_northbridge(root, root_ids);
295 	}
296 
297 	if (amd_gart_present())
298 		amd_northbridges.flags |= AMD_NB_GART;
299 
300 	/*
301 	 * Check for L3 cache presence.
302 	 */
303 	if (!cpuid_edx(0x80000006))
304 		return 0;
305 
306 	/*
307 	 * Some CPU families support L3 Cache Index Disable. There are some
308 	 * limitations because of E382 and E388 on family 0x10.
309 	 */
310 	if (boot_cpu_data.x86 == 0x10 &&
311 	    boot_cpu_data.x86_model >= 0x8 &&
312 	    (boot_cpu_data.x86_model > 0x9 ||
313 	     boot_cpu_data.x86_stepping >= 0x1))
314 		amd_northbridges.flags |= AMD_NB_L3_INDEX_DISABLE;
315 
316 	if (boot_cpu_data.x86 == 0x15)
317 		amd_northbridges.flags |= AMD_NB_L3_INDEX_DISABLE;
318 
319 	/* L3 cache partitioning is supported on family 0x15 */
320 	if (boot_cpu_data.x86 == 0x15)
321 		amd_northbridges.flags |= AMD_NB_L3_PARTITIONING;
322 
323 	return 0;
324 }
325 
326 /*
327  * Ignores subdevice/subvendor but as far as I can figure out
328  * they're useless anyways
329  */
330 bool __init early_is_amd_nb(u32 device)
331 {
332 	const struct pci_device_id *misc_ids = amd_nb_misc_ids;
333 	const struct pci_device_id *id;
334 	u32 vendor = device & 0xffff;
335 
336 	if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD &&
337 	    boot_cpu_data.x86_vendor != X86_VENDOR_HYGON)
338 		return false;
339 
340 	if (boot_cpu_data.x86_vendor == X86_VENDOR_HYGON)
341 		misc_ids = hygon_nb_misc_ids;
342 
343 	device >>= 16;
344 	for (id = misc_ids; id->vendor; id++)
345 		if (vendor == id->vendor && device == id->device)
346 			return true;
347 	return false;
348 }
349 
350 struct resource *amd_get_mmconfig_range(struct resource *res)
351 {
352 	u32 address;
353 	u64 base, msr;
354 	unsigned int segn_busn_bits;
355 
356 	if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD &&
357 	    boot_cpu_data.x86_vendor != X86_VENDOR_HYGON)
358 		return NULL;
359 
360 	/* assume all cpus from fam10h have mmconfig */
361 	if (boot_cpu_data.x86 < 0x10)
362 		return NULL;
363 
364 	address = MSR_FAM10H_MMIO_CONF_BASE;
365 	rdmsrl(address, msr);
366 
367 	/* mmconfig is not enabled */
368 	if (!(msr & FAM10H_MMIO_CONF_ENABLE))
369 		return NULL;
370 
371 	base = msr & (FAM10H_MMIO_CONF_BASE_MASK<<FAM10H_MMIO_CONF_BASE_SHIFT);
372 
373 	segn_busn_bits = (msr >> FAM10H_MMIO_CONF_BUSRANGE_SHIFT) &
374 			 FAM10H_MMIO_CONF_BUSRANGE_MASK;
375 
376 	res->flags = IORESOURCE_MEM;
377 	res->start = base;
378 	res->end = base + (1ULL<<(segn_busn_bits + 20)) - 1;
379 	return res;
380 }
381 
382 int amd_get_subcaches(int cpu)
383 {
384 	struct pci_dev *link = node_to_amd_nb(topology_die_id(cpu))->link;
385 	unsigned int mask;
386 
387 	if (!amd_nb_has_feature(AMD_NB_L3_PARTITIONING))
388 		return 0;
389 
390 	pci_read_config_dword(link, 0x1d4, &mask);
391 
392 	return (mask >> (4 * cpu_data(cpu).cpu_core_id)) & 0xf;
393 }
394 
395 int amd_set_subcaches(int cpu, unsigned long mask)
396 {
397 	static unsigned int reset, ban;
398 	struct amd_northbridge *nb = node_to_amd_nb(topology_die_id(cpu));
399 	unsigned int reg;
400 	int cuid;
401 
402 	if (!amd_nb_has_feature(AMD_NB_L3_PARTITIONING) || mask > 0xf)
403 		return -EINVAL;
404 
405 	/* if necessary, collect reset state of L3 partitioning and BAN mode */
406 	if (reset == 0) {
407 		pci_read_config_dword(nb->link, 0x1d4, &reset);
408 		pci_read_config_dword(nb->misc, 0x1b8, &ban);
409 		ban &= 0x180000;
410 	}
411 
412 	/* deactivate BAN mode if any subcaches are to be disabled */
413 	if (mask != 0xf) {
414 		pci_read_config_dword(nb->misc, 0x1b8, &reg);
415 		pci_write_config_dword(nb->misc, 0x1b8, reg & ~0x180000);
416 	}
417 
418 	cuid = cpu_data(cpu).cpu_core_id;
419 	mask <<= 4 * cuid;
420 	mask |= (0xf ^ (1 << cuid)) << 26;
421 
422 	pci_write_config_dword(nb->link, 0x1d4, mask);
423 
424 	/* reset BAN mode if L3 partitioning returned to reset state */
425 	pci_read_config_dword(nb->link, 0x1d4, &reg);
426 	if (reg == reset) {
427 		pci_read_config_dword(nb->misc, 0x1b8, &reg);
428 		reg &= ~0x180000;
429 		pci_write_config_dword(nb->misc, 0x1b8, reg | ban);
430 	}
431 
432 	return 0;
433 }
434 
435 static void amd_cache_gart(void)
436 {
437 	u16 i;
438 
439 	if (!amd_nb_has_feature(AMD_NB_GART))
440 		return;
441 
442 	flush_words = kmalloc_array(amd_northbridges.num, sizeof(u32), GFP_KERNEL);
443 	if (!flush_words) {
444 		amd_northbridges.flags &= ~AMD_NB_GART;
445 		pr_notice("Cannot initialize GART flush words, GART support disabled\n");
446 		return;
447 	}
448 
449 	for (i = 0; i != amd_northbridges.num; i++)
450 		pci_read_config_dword(node_to_amd_nb(i)->misc, 0x9c, &flush_words[i]);
451 }
452 
453 void amd_flush_garts(void)
454 {
455 	int flushed, i;
456 	unsigned long flags;
457 	static DEFINE_SPINLOCK(gart_lock);
458 
459 	if (!amd_nb_has_feature(AMD_NB_GART))
460 		return;
461 
462 	/*
463 	 * Avoid races between AGP and IOMMU. In theory it's not needed
464 	 * but I'm not sure if the hardware won't lose flush requests
465 	 * when another is pending. This whole thing is so expensive anyways
466 	 * that it doesn't matter to serialize more. -AK
467 	 */
468 	spin_lock_irqsave(&gart_lock, flags);
469 	flushed = 0;
470 	for (i = 0; i < amd_northbridges.num; i++) {
471 		pci_write_config_dword(node_to_amd_nb(i)->misc, 0x9c,
472 				       flush_words[i] | 1);
473 		flushed++;
474 	}
475 	for (i = 0; i < amd_northbridges.num; i++) {
476 		u32 w;
477 		/* Make sure the hardware actually executed the flush*/
478 		for (;;) {
479 			pci_read_config_dword(node_to_amd_nb(i)->misc,
480 					      0x9c, &w);
481 			if (!(w & 1))
482 				break;
483 			cpu_relax();
484 		}
485 	}
486 	spin_unlock_irqrestore(&gart_lock, flags);
487 	if (!flushed)
488 		pr_notice("nothing to flush?\n");
489 }
490 EXPORT_SYMBOL_GPL(amd_flush_garts);
491 
492 static void __fix_erratum_688(void *info)
493 {
494 #define MSR_AMD64_IC_CFG 0xC0011021
495 
496 	msr_set_bit(MSR_AMD64_IC_CFG, 3);
497 	msr_set_bit(MSR_AMD64_IC_CFG, 14);
498 }
499 
500 /* Apply erratum 688 fix so machines without a BIOS fix work. */
501 static __init void fix_erratum_688(void)
502 {
503 	struct pci_dev *F4;
504 	u32 val;
505 
506 	if (boot_cpu_data.x86 != 0x14)
507 		return;
508 
509 	if (!amd_northbridges.num)
510 		return;
511 
512 	F4 = node_to_amd_nb(0)->link;
513 	if (!F4)
514 		return;
515 
516 	if (pci_read_config_dword(F4, 0x164, &val))
517 		return;
518 
519 	if (val & BIT(2))
520 		return;
521 
522 	on_each_cpu(__fix_erratum_688, NULL, 0);
523 
524 	pr_info("x86/cpu/AMD: CPU erratum 688 worked around\n");
525 }
526 
527 static __init int init_amd_nbs(void)
528 {
529 	amd_cache_northbridges();
530 	amd_cache_gart();
531 
532 	fix_erratum_688();
533 
534 	return 0;
535 }
536 
537 /* This has to go after the PCI subsystem */
538 fs_initcall(init_amd_nbs);
539