xref: /netbsd-src/sys/external/bsd/drm2/dist/drm/amd/amdkfd/kfd_topology.c (revision 4d342c046e3288fb5a1edcd33cfec48c41c80664)
1 /*	$NetBSD: kfd_topology.c,v 1.2 2018/08/27 04:58:20 riastradh Exp $	*/
2 
3 /*
4  * Copyright 2014 Advanced Micro Devices, Inc.
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a
7  * copy of this software and associated documentation files (the "Software"),
8  * to deal in the Software without restriction, including without limitation
9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
10  * and/or sell copies of the Software, and to permit persons to whom the
11  * Software is furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice shall be included in
14  * all copies or substantial portions of the Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
19  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
20  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
21  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
22  * OTHER DEALINGS IN THE SOFTWARE.
23  */
24 
25 #include <sys/cdefs.h>
26 __KERNEL_RCSID(0, "$NetBSD: kfd_topology.c,v 1.2 2018/08/27 04:58:20 riastradh Exp $");
27 
28 #include <linux/types.h>
29 #include <linux/kernel.h>
30 #include <linux/pci.h>
31 #include <linux/errno.h>
32 #include <linux/acpi.h>
33 #include <linux/hash.h>
34 #include <linux/cpufreq.h>
35 #include <linux/log2.h>
36 
37 #include "kfd_priv.h"
38 #include "kfd_crat.h"
39 #include "kfd_topology.h"
40 
41 static struct list_head topology_device_list;
42 static int topology_crat_parsed;
43 static struct kfd_system_properties sys_props;
44 
45 static DECLARE_RWSEM(topology_lock);
46 
47 struct kfd_dev *kfd_device_by_id(uint32_t gpu_id)
48 {
49 	struct kfd_topology_device *top_dev;
50 	struct kfd_dev *device = NULL;
51 
52 	down_read(&topology_lock);
53 
54 	list_for_each_entry(top_dev, &topology_device_list, list)
55 		if (top_dev->gpu_id == gpu_id) {
56 			device = top_dev->gpu;
57 			break;
58 		}
59 
60 	up_read(&topology_lock);
61 
62 	return device;
63 }
64 
65 struct kfd_dev *kfd_device_by_pci_dev(const struct pci_dev *pdev)
66 {
67 	struct kfd_topology_device *top_dev;
68 	struct kfd_dev *device = NULL;
69 
70 	down_read(&topology_lock);
71 
72 	list_for_each_entry(top_dev, &topology_device_list, list)
73 		if (top_dev->gpu->pdev == pdev) {
74 			device = top_dev->gpu;
75 			break;
76 		}
77 
78 	up_read(&topology_lock);
79 
80 	return device;
81 }
82 
83 static int kfd_topology_get_crat_acpi(void *crat_image, size_t *size)
84 {
85 	struct acpi_table_header *crat_table;
86 	acpi_status status;
87 
88 	if (!size)
89 		return -EINVAL;
90 
91 	/*
92 	 * Fetch the CRAT table from ACPI
93 	 */
94 	status = acpi_get_table(CRAT_SIGNATURE, 0, &crat_table);
95 	if (status == AE_NOT_FOUND) {
96 		pr_warn("CRAT table not found\n");
97 		return -ENODATA;
98 	} else if (ACPI_FAILURE(status)) {
99 		const char *err = acpi_format_exception(status);
100 
101 		pr_err("CRAT table error: %s\n", err);
102 		return -EINVAL;
103 	}
104 
105 	if (*size >= crat_table->length && crat_image != NULL)
106 		memcpy(crat_image, crat_table, crat_table->length);
107 
108 	*size = crat_table->length;
109 
110 	return 0;
111 }
112 
113 static void kfd_populated_cu_info_cpu(struct kfd_topology_device *dev,
114 		struct crat_subtype_computeunit *cu)
115 {
116 	BUG_ON(!dev);
117 	BUG_ON(!cu);
118 
119 	dev->node_props.cpu_cores_count = cu->num_cpu_cores;
120 	dev->node_props.cpu_core_id_base = cu->processor_id_low;
121 	if (cu->hsa_capability & CRAT_CU_FLAGS_IOMMU_PRESENT)
122 		dev->node_props.capability |= HSA_CAP_ATS_PRESENT;
123 
124 	pr_info("CU CPU: cores=%d id_base=%d\n", cu->num_cpu_cores,
125 			cu->processor_id_low);
126 }
127 
128 static void kfd_populated_cu_info_gpu(struct kfd_topology_device *dev,
129 		struct crat_subtype_computeunit *cu)
130 {
131 	BUG_ON(!dev);
132 	BUG_ON(!cu);
133 
134 	dev->node_props.simd_id_base = cu->processor_id_low;
135 	dev->node_props.simd_count = cu->num_simd_cores;
136 	dev->node_props.lds_size_in_kb = cu->lds_size_in_kb;
137 	dev->node_props.max_waves_per_simd = cu->max_waves_simd;
138 	dev->node_props.wave_front_size = cu->wave_front_size;
139 	dev->node_props.mem_banks_count = cu->num_banks;
140 	dev->node_props.array_count = cu->num_arrays;
141 	dev->node_props.cu_per_simd_array = cu->num_cu_per_array;
142 	dev->node_props.simd_per_cu = cu->num_simd_per_cu;
143 	dev->node_props.max_slots_scratch_cu = cu->max_slots_scatch_cu;
144 	if (cu->hsa_capability & CRAT_CU_FLAGS_HOT_PLUGGABLE)
145 		dev->node_props.capability |= HSA_CAP_HOT_PLUGGABLE;
146 	pr_info("CU GPU: simds=%d id_base=%d\n", cu->num_simd_cores,
147 				cu->processor_id_low);
148 }
149 
150 /* kfd_parse_subtype_cu is called when the topology mutex is already acquired */
151 static int kfd_parse_subtype_cu(struct crat_subtype_computeunit *cu)
152 {
153 	struct kfd_topology_device *dev;
154 	int i = 0;
155 
156 	BUG_ON(!cu);
157 
158 	pr_info("Found CU entry in CRAT table with proximity_domain=%d caps=%x\n",
159 			cu->proximity_domain, cu->hsa_capability);
160 	list_for_each_entry(dev, &topology_device_list, list) {
161 		if (cu->proximity_domain == i) {
162 			if (cu->flags & CRAT_CU_FLAGS_CPU_PRESENT)
163 				kfd_populated_cu_info_cpu(dev, cu);
164 
165 			if (cu->flags & CRAT_CU_FLAGS_GPU_PRESENT)
166 				kfd_populated_cu_info_gpu(dev, cu);
167 			break;
168 		}
169 		i++;
170 	}
171 
172 	return 0;
173 }
174 
175 /*
176  * kfd_parse_subtype_mem is called when the topology mutex is
177  * already acquired
178  */
179 static int kfd_parse_subtype_mem(struct crat_subtype_memory *mem)
180 {
181 	struct kfd_mem_properties *props;
182 	struct kfd_topology_device *dev;
183 	int i = 0;
184 
185 	BUG_ON(!mem);
186 
187 	pr_info("Found memory entry in CRAT table with proximity_domain=%d\n",
188 			mem->promixity_domain);
189 	list_for_each_entry(dev, &topology_device_list, list) {
190 		if (mem->promixity_domain == i) {
191 			props = kfd_alloc_struct(props);
192 			if (props == NULL)
193 				return -ENOMEM;
194 
195 			if (dev->node_props.cpu_cores_count == 0)
196 				props->heap_type = HSA_MEM_HEAP_TYPE_FB_PRIVATE;
197 			else
198 				props->heap_type = HSA_MEM_HEAP_TYPE_SYSTEM;
199 
200 			if (mem->flags & CRAT_MEM_FLAGS_HOT_PLUGGABLE)
201 				props->flags |= HSA_MEM_FLAGS_HOT_PLUGGABLE;
202 			if (mem->flags & CRAT_MEM_FLAGS_NON_VOLATILE)
203 				props->flags |= HSA_MEM_FLAGS_NON_VOLATILE;
204 
205 			props->size_in_bytes =
206 				((uint64_t)mem->length_high << 32) +
207 							mem->length_low;
208 			props->width = mem->width;
209 
210 			dev->mem_bank_count++;
211 			list_add_tail(&props->list, &dev->mem_props);
212 
213 			break;
214 		}
215 		i++;
216 	}
217 
218 	return 0;
219 }
220 
221 /*
222  * kfd_parse_subtype_cache is called when the topology mutex
223  * is already acquired
224  */
225 static int kfd_parse_subtype_cache(struct crat_subtype_cache *cache)
226 {
227 	struct kfd_cache_properties *props;
228 	struct kfd_topology_device *dev;
229 	uint32_t id;
230 
231 	BUG_ON(!cache);
232 
233 	id = cache->processor_id_low;
234 
235 	pr_info("Found cache entry in CRAT table with processor_id=%d\n", id);
236 	list_for_each_entry(dev, &topology_device_list, list)
237 		if (id == dev->node_props.cpu_core_id_base ||
238 		    id == dev->node_props.simd_id_base) {
239 			props = kfd_alloc_struct(props);
240 			if (props == NULL)
241 				return -ENOMEM;
242 
243 			props->processor_id_low = id;
244 			props->cache_level = cache->cache_level;
245 			props->cache_size = cache->cache_size;
246 			props->cacheline_size = cache->cache_line_size;
247 			props->cachelines_per_tag = cache->lines_per_tag;
248 			props->cache_assoc = cache->associativity;
249 			props->cache_latency = cache->cache_latency;
250 
251 			if (cache->flags & CRAT_CACHE_FLAGS_DATA_CACHE)
252 				props->cache_type |= HSA_CACHE_TYPE_DATA;
253 			if (cache->flags & CRAT_CACHE_FLAGS_INST_CACHE)
254 				props->cache_type |= HSA_CACHE_TYPE_INSTRUCTION;
255 			if (cache->flags & CRAT_CACHE_FLAGS_CPU_CACHE)
256 				props->cache_type |= HSA_CACHE_TYPE_CPU;
257 			if (cache->flags & CRAT_CACHE_FLAGS_SIMD_CACHE)
258 				props->cache_type |= HSA_CACHE_TYPE_HSACU;
259 
260 			dev->cache_count++;
261 			dev->node_props.caches_count++;
262 			list_add_tail(&props->list, &dev->cache_props);
263 
264 			break;
265 		}
266 
267 	return 0;
268 }
269 
270 /*
271  * kfd_parse_subtype_iolink is called when the topology mutex
272  * is already acquired
273  */
274 static int kfd_parse_subtype_iolink(struct crat_subtype_iolink *iolink)
275 {
276 	struct kfd_iolink_properties *props;
277 	struct kfd_topology_device *dev;
278 	uint32_t i = 0;
279 	uint32_t id_from;
280 	uint32_t id_to;
281 
282 	BUG_ON(!iolink);
283 
284 	id_from = iolink->proximity_domain_from;
285 	id_to = iolink->proximity_domain_to;
286 
287 	pr_info("Found IO link entry in CRAT table with id_from=%d\n", id_from);
288 	list_for_each_entry(dev, &topology_device_list, list) {
289 		if (id_from == i) {
290 			props = kfd_alloc_struct(props);
291 			if (props == NULL)
292 				return -ENOMEM;
293 
294 			props->node_from = id_from;
295 			props->node_to = id_to;
296 			props->ver_maj = iolink->version_major;
297 			props->ver_min = iolink->version_minor;
298 
299 			/*
300 			 * weight factor (derived from CDIR), currently always 1
301 			 */
302 			props->weight = 1;
303 
304 			props->min_latency = iolink->minimum_latency;
305 			props->max_latency = iolink->maximum_latency;
306 			props->min_bandwidth = iolink->minimum_bandwidth_mbs;
307 			props->max_bandwidth = iolink->maximum_bandwidth_mbs;
308 			props->rec_transfer_size =
309 					iolink->recommended_transfer_size;
310 
311 			dev->io_link_count++;
312 			dev->node_props.io_links_count++;
313 			list_add_tail(&props->list, &dev->io_link_props);
314 
315 			break;
316 		}
317 		i++;
318 	}
319 
320 	return 0;
321 }
322 
323 static int kfd_parse_subtype(struct crat_subtype_generic *sub_type_hdr)
324 {
325 	struct crat_subtype_computeunit *cu;
326 	struct crat_subtype_memory *mem;
327 	struct crat_subtype_cache *cache;
328 	struct crat_subtype_iolink *iolink;
329 	int ret = 0;
330 
331 	BUG_ON(!sub_type_hdr);
332 
333 	switch (sub_type_hdr->type) {
334 	case CRAT_SUBTYPE_COMPUTEUNIT_AFFINITY:
335 		cu = (struct crat_subtype_computeunit *)sub_type_hdr;
336 		ret = kfd_parse_subtype_cu(cu);
337 		break;
338 	case CRAT_SUBTYPE_MEMORY_AFFINITY:
339 		mem = (struct crat_subtype_memory *)sub_type_hdr;
340 		ret = kfd_parse_subtype_mem(mem);
341 		break;
342 	case CRAT_SUBTYPE_CACHE_AFFINITY:
343 		cache = (struct crat_subtype_cache *)sub_type_hdr;
344 		ret = kfd_parse_subtype_cache(cache);
345 		break;
346 	case CRAT_SUBTYPE_TLB_AFFINITY:
347 		/*
348 		 * For now, nothing to do here
349 		 */
350 		pr_info("Found TLB entry in CRAT table (not processing)\n");
351 		break;
352 	case CRAT_SUBTYPE_CCOMPUTE_AFFINITY:
353 		/*
354 		 * For now, nothing to do here
355 		 */
356 		pr_info("Found CCOMPUTE entry in CRAT table (not processing)\n");
357 		break;
358 	case CRAT_SUBTYPE_IOLINK_AFFINITY:
359 		iolink = (struct crat_subtype_iolink *)sub_type_hdr;
360 		ret = kfd_parse_subtype_iolink(iolink);
361 		break;
362 	default:
363 		pr_warn("Unknown subtype (%d) in CRAT\n",
364 				sub_type_hdr->type);
365 	}
366 
367 	return ret;
368 }
369 
370 static void kfd_release_topology_device(struct kfd_topology_device *dev)
371 {
372 	struct kfd_mem_properties *mem;
373 	struct kfd_cache_properties *cache;
374 	struct kfd_iolink_properties *iolink;
375 
376 	BUG_ON(!dev);
377 
378 	list_del(&dev->list);
379 
380 	while (dev->mem_props.next != &dev->mem_props) {
381 		mem = container_of(dev->mem_props.next,
382 				struct kfd_mem_properties, list);
383 		list_del(&mem->list);
384 		kfree(mem);
385 	}
386 
387 	while (dev->cache_props.next != &dev->cache_props) {
388 		cache = container_of(dev->cache_props.next,
389 				struct kfd_cache_properties, list);
390 		list_del(&cache->list);
391 		kfree(cache);
392 	}
393 
394 	while (dev->io_link_props.next != &dev->io_link_props) {
395 		iolink = container_of(dev->io_link_props.next,
396 				struct kfd_iolink_properties, list);
397 		list_del(&iolink->list);
398 		kfree(iolink);
399 	}
400 
401 	kfree(dev);
402 
403 	sys_props.num_devices--;
404 }
405 
406 static void kfd_release_live_view(void)
407 {
408 	struct kfd_topology_device *dev;
409 
410 	while (topology_device_list.next != &topology_device_list) {
411 		dev = container_of(topology_device_list.next,
412 				 struct kfd_topology_device, list);
413 		kfd_release_topology_device(dev);
414 }
415 
416 	memset(&sys_props, 0, sizeof(sys_props));
417 }
418 
419 static struct kfd_topology_device *kfd_create_topology_device(void)
420 {
421 	struct kfd_topology_device *dev;
422 
423 	dev = kfd_alloc_struct(dev);
424 	if (dev == NULL) {
425 		pr_err("No memory to allocate a topology device");
426 		return NULL;
427 	}
428 
429 	INIT_LIST_HEAD(&dev->mem_props);
430 	INIT_LIST_HEAD(&dev->cache_props);
431 	INIT_LIST_HEAD(&dev->io_link_props);
432 
433 	list_add_tail(&dev->list, &topology_device_list);
434 	sys_props.num_devices++;
435 
436 	return dev;
437 }
438 
439 static int kfd_parse_crat_table(void *crat_image)
440 {
441 	struct kfd_topology_device *top_dev;
442 	struct crat_subtype_generic *sub_type_hdr;
443 	uint16_t node_id;
444 	int ret;
445 	struct crat_header *crat_table = (struct crat_header *)crat_image;
446 	uint16_t num_nodes;
447 	uint32_t image_len;
448 
449 	if (!crat_image)
450 		return -EINVAL;
451 
452 	num_nodes = crat_table->num_domains;
453 	image_len = crat_table->length;
454 
455 	pr_info("Parsing CRAT table with %d nodes\n", num_nodes);
456 
457 	for (node_id = 0; node_id < num_nodes; node_id++) {
458 		top_dev = kfd_create_topology_device();
459 		if (!top_dev) {
460 			kfd_release_live_view();
461 			return -ENOMEM;
462 		}
463 	}
464 
465 	sys_props.platform_id =
466 		(*((uint64_t *)crat_table->oem_id)) & CRAT_OEMID_64BIT_MASK;
467 	sys_props.platform_oem = *((uint64_t *)crat_table->oem_table_id);
468 	sys_props.platform_rev = crat_table->revision;
469 
470 	sub_type_hdr = (struct crat_subtype_generic *)(crat_table+1);
471 	while ((char *)sub_type_hdr + sizeof(struct crat_subtype_generic) <
472 			((char *)crat_image) + image_len) {
473 		if (sub_type_hdr->flags & CRAT_SUBTYPE_FLAGS_ENABLED) {
474 			ret = kfd_parse_subtype(sub_type_hdr);
475 			if (ret != 0) {
476 				kfd_release_live_view();
477 				return ret;
478 			}
479 		}
480 
481 		sub_type_hdr = (typeof(sub_type_hdr))((char *)sub_type_hdr +
482 				sub_type_hdr->length);
483 	}
484 
485 	sys_props.generation_count++;
486 	topology_crat_parsed = 1;
487 
488 	return 0;
489 }
490 
491 
492 #define sysfs_show_gen_prop(buffer, fmt, ...) \
493 		snprintf(buffer, PAGE_SIZE, "%s"fmt, buffer, __VA_ARGS__)
494 #define sysfs_show_32bit_prop(buffer, name, value) \
495 		sysfs_show_gen_prop(buffer, "%s %u\n", name, value)
496 #define sysfs_show_64bit_prop(buffer, name, value) \
497 		sysfs_show_gen_prop(buffer, "%s %llu\n", name, value)
498 #define sysfs_show_32bit_val(buffer, value) \
499 		sysfs_show_gen_prop(buffer, "%u\n", value)
500 #define sysfs_show_str_val(buffer, value) \
501 		sysfs_show_gen_prop(buffer, "%s\n", value)
502 
503 static ssize_t sysprops_show(struct kobject *kobj, struct attribute *attr,
504 		char *buffer)
505 {
506 	ssize_t ret;
507 
508 	/* Making sure that the buffer is an empty string */
509 	buffer[0] = 0;
510 
511 	if (attr == &sys_props.attr_genid) {
512 		ret = sysfs_show_32bit_val(buffer, sys_props.generation_count);
513 	} else if (attr == &sys_props.attr_props) {
514 		sysfs_show_64bit_prop(buffer, "platform_oem",
515 				sys_props.platform_oem);
516 		sysfs_show_64bit_prop(buffer, "platform_id",
517 				sys_props.platform_id);
518 		ret = sysfs_show_64bit_prop(buffer, "platform_rev",
519 				sys_props.platform_rev);
520 	} else {
521 		ret = -EINVAL;
522 	}
523 
524 	return ret;
525 }
526 
527 static void kfd_topology_kobj_release(struct kobject *kobj)
528 {
529 	kfree(kobj);
530 }
531 
532 static const struct sysfs_ops sysprops_ops = {
533 	.show = sysprops_show,
534 };
535 
536 static struct kobj_type sysprops_type = {
537 	.release = kfd_topology_kobj_release,
538 	.sysfs_ops = &sysprops_ops,
539 };
540 
541 static ssize_t iolink_show(struct kobject *kobj, struct attribute *attr,
542 		char *buffer)
543 {
544 	ssize_t ret;
545 	struct kfd_iolink_properties *iolink;
546 
547 	/* Making sure that the buffer is an empty string */
548 	buffer[0] = 0;
549 
550 	iolink = container_of(attr, struct kfd_iolink_properties, attr);
551 	sysfs_show_32bit_prop(buffer, "type", iolink->iolink_type);
552 	sysfs_show_32bit_prop(buffer, "version_major", iolink->ver_maj);
553 	sysfs_show_32bit_prop(buffer, "version_minor", iolink->ver_min);
554 	sysfs_show_32bit_prop(buffer, "node_from", iolink->node_from);
555 	sysfs_show_32bit_prop(buffer, "node_to", iolink->node_to);
556 	sysfs_show_32bit_prop(buffer, "weight", iolink->weight);
557 	sysfs_show_32bit_prop(buffer, "min_latency", iolink->min_latency);
558 	sysfs_show_32bit_prop(buffer, "max_latency", iolink->max_latency);
559 	sysfs_show_32bit_prop(buffer, "min_bandwidth", iolink->min_bandwidth);
560 	sysfs_show_32bit_prop(buffer, "max_bandwidth", iolink->max_bandwidth);
561 	sysfs_show_32bit_prop(buffer, "recommended_transfer_size",
562 			iolink->rec_transfer_size);
563 	ret = sysfs_show_32bit_prop(buffer, "flags", iolink->flags);
564 
565 	return ret;
566 }
567 
568 static const struct sysfs_ops iolink_ops = {
569 	.show = iolink_show,
570 };
571 
572 static struct kobj_type iolink_type = {
573 	.release = kfd_topology_kobj_release,
574 	.sysfs_ops = &iolink_ops,
575 };
576 
577 static ssize_t mem_show(struct kobject *kobj, struct attribute *attr,
578 		char *buffer)
579 {
580 	ssize_t ret;
581 	struct kfd_mem_properties *mem;
582 
583 	/* Making sure that the buffer is an empty string */
584 	buffer[0] = 0;
585 
586 	mem = container_of(attr, struct kfd_mem_properties, attr);
587 	sysfs_show_32bit_prop(buffer, "heap_type", mem->heap_type);
588 	sysfs_show_64bit_prop(buffer, "size_in_bytes", mem->size_in_bytes);
589 	sysfs_show_32bit_prop(buffer, "flags", mem->flags);
590 	sysfs_show_32bit_prop(buffer, "width", mem->width);
591 	ret = sysfs_show_32bit_prop(buffer, "mem_clk_max", mem->mem_clk_max);
592 
593 	return ret;
594 }
595 
596 static const struct sysfs_ops mem_ops = {
597 	.show = mem_show,
598 };
599 
600 static struct kobj_type mem_type = {
601 	.release = kfd_topology_kobj_release,
602 	.sysfs_ops = &mem_ops,
603 };
604 
605 static ssize_t kfd_cache_show(struct kobject *kobj, struct attribute *attr,
606 		char *buffer)
607 {
608 	ssize_t ret;
609 	uint32_t i;
610 	struct kfd_cache_properties *cache;
611 
612 	/* Making sure that the buffer is an empty string */
613 	buffer[0] = 0;
614 
615 	cache = container_of(attr, struct kfd_cache_properties, attr);
616 	sysfs_show_32bit_prop(buffer, "processor_id_low",
617 			cache->processor_id_low);
618 	sysfs_show_32bit_prop(buffer, "level", cache->cache_level);
619 	sysfs_show_32bit_prop(buffer, "size", cache->cache_size);
620 	sysfs_show_32bit_prop(buffer, "cache_line_size", cache->cacheline_size);
621 	sysfs_show_32bit_prop(buffer, "cache_lines_per_tag",
622 			cache->cachelines_per_tag);
623 	sysfs_show_32bit_prop(buffer, "association", cache->cache_assoc);
624 	sysfs_show_32bit_prop(buffer, "latency", cache->cache_latency);
625 	sysfs_show_32bit_prop(buffer, "type", cache->cache_type);
626 	snprintf(buffer, PAGE_SIZE, "%ssibling_map ", buffer);
627 	for (i = 0; i < KFD_TOPOLOGY_CPU_SIBLINGS; i++)
628 		ret = snprintf(buffer, PAGE_SIZE, "%s%d%s",
629 				buffer, cache->sibling_map[i],
630 				(i == KFD_TOPOLOGY_CPU_SIBLINGS-1) ?
631 						"\n" : ",");
632 
633 	return ret;
634 }
635 
636 static const struct sysfs_ops cache_ops = {
637 	.show = kfd_cache_show,
638 };
639 
640 static struct kobj_type cache_type = {
641 	.release = kfd_topology_kobj_release,
642 	.sysfs_ops = &cache_ops,
643 };
644 
645 static ssize_t node_show(struct kobject *kobj, struct attribute *attr,
646 		char *buffer)
647 {
648 	struct kfd_topology_device *dev;
649 	char public_name[KFD_TOPOLOGY_PUBLIC_NAME_SIZE];
650 	uint32_t i;
651 	uint32_t log_max_watch_addr;
652 
653 	/* Making sure that the buffer is an empty string */
654 	buffer[0] = 0;
655 
656 	if (strcmp(attr->name, "gpu_id") == 0) {
657 		dev = container_of(attr, struct kfd_topology_device,
658 				attr_gpuid);
659 		return sysfs_show_32bit_val(buffer, dev->gpu_id);
660 	}
661 
662 	if (strcmp(attr->name, "name") == 0) {
663 		dev = container_of(attr, struct kfd_topology_device,
664 				attr_name);
665 		for (i = 0; i < KFD_TOPOLOGY_PUBLIC_NAME_SIZE; i++) {
666 			public_name[i] =
667 					(char)dev->node_props.marketing_name[i];
668 			if (dev->node_props.marketing_name[i] == 0)
669 				break;
670 		}
671 		public_name[KFD_TOPOLOGY_PUBLIC_NAME_SIZE-1] = 0x0;
672 		return sysfs_show_str_val(buffer, public_name);
673 	}
674 
675 	dev = container_of(attr, struct kfd_topology_device,
676 			attr_props);
677 	sysfs_show_32bit_prop(buffer, "cpu_cores_count",
678 			dev->node_props.cpu_cores_count);
679 	sysfs_show_32bit_prop(buffer, "simd_count",
680 			dev->node_props.simd_count);
681 
682 	if (dev->mem_bank_count < dev->node_props.mem_banks_count) {
683 		pr_warn("kfd: mem_banks_count truncated from %d to %d\n",
684 				dev->node_props.mem_banks_count,
685 				dev->mem_bank_count);
686 		sysfs_show_32bit_prop(buffer, "mem_banks_count",
687 				dev->mem_bank_count);
688 	} else {
689 		sysfs_show_32bit_prop(buffer, "mem_banks_count",
690 				dev->node_props.mem_banks_count);
691 	}
692 
693 	sysfs_show_32bit_prop(buffer, "caches_count",
694 			dev->node_props.caches_count);
695 	sysfs_show_32bit_prop(buffer, "io_links_count",
696 			dev->node_props.io_links_count);
697 	sysfs_show_32bit_prop(buffer, "cpu_core_id_base",
698 			dev->node_props.cpu_core_id_base);
699 	sysfs_show_32bit_prop(buffer, "simd_id_base",
700 			dev->node_props.simd_id_base);
701 	sysfs_show_32bit_prop(buffer, "max_waves_per_simd",
702 			dev->node_props.max_waves_per_simd);
703 	sysfs_show_32bit_prop(buffer, "lds_size_in_kb",
704 			dev->node_props.lds_size_in_kb);
705 	sysfs_show_32bit_prop(buffer, "gds_size_in_kb",
706 			dev->node_props.gds_size_in_kb);
707 	sysfs_show_32bit_prop(buffer, "wave_front_size",
708 			dev->node_props.wave_front_size);
709 	sysfs_show_32bit_prop(buffer, "array_count",
710 			dev->node_props.array_count);
711 	sysfs_show_32bit_prop(buffer, "simd_arrays_per_engine",
712 			dev->node_props.simd_arrays_per_engine);
713 	sysfs_show_32bit_prop(buffer, "cu_per_simd_array",
714 			dev->node_props.cu_per_simd_array);
715 	sysfs_show_32bit_prop(buffer, "simd_per_cu",
716 			dev->node_props.simd_per_cu);
717 	sysfs_show_32bit_prop(buffer, "max_slots_scratch_cu",
718 			dev->node_props.max_slots_scratch_cu);
719 	sysfs_show_32bit_prop(buffer, "vendor_id",
720 			dev->node_props.vendor_id);
721 	sysfs_show_32bit_prop(buffer, "device_id",
722 			dev->node_props.device_id);
723 	sysfs_show_32bit_prop(buffer, "location_id",
724 			dev->node_props.location_id);
725 
726 	if (dev->gpu) {
727 		log_max_watch_addr =
728 			__ilog2_u32(dev->gpu->device_info->num_of_watch_points);
729 
730 		if (log_max_watch_addr) {
731 			dev->node_props.capability |=
732 					HSA_CAP_WATCH_POINTS_SUPPORTED;
733 
734 			dev->node_props.capability |=
735 				((log_max_watch_addr <<
736 					HSA_CAP_WATCH_POINTS_TOTALBITS_SHIFT) &
737 				HSA_CAP_WATCH_POINTS_TOTALBITS_MASK);
738 		}
739 
740 		sysfs_show_32bit_prop(buffer, "max_engine_clk_fcompute",
741 			dev->gpu->kfd2kgd->get_max_engine_clock_in_mhz(
742 					dev->gpu->kgd));
743 
744 		sysfs_show_64bit_prop(buffer, "local_mem_size",
745 				(unsigned long long int) 0);
746 
747 		sysfs_show_32bit_prop(buffer, "fw_version",
748 			dev->gpu->kfd2kgd->get_fw_version(
749 						dev->gpu->kgd,
750 						KGD_ENGINE_MEC1));
751 		sysfs_show_32bit_prop(buffer, "capability",
752 				dev->node_props.capability);
753 	}
754 
755 	return sysfs_show_32bit_prop(buffer, "max_engine_clk_ccompute",
756 					cpufreq_quick_get_max(0)/1000);
757 }
758 
759 static const struct sysfs_ops node_ops = {
760 	.show = node_show,
761 };
762 
763 static struct kobj_type node_type = {
764 	.release = kfd_topology_kobj_release,
765 	.sysfs_ops = &node_ops,
766 };
767 
768 static void kfd_remove_sysfs_file(struct kobject *kobj, struct attribute *attr)
769 {
770 	sysfs_remove_file(kobj, attr);
771 	kobject_del(kobj);
772 	kobject_put(kobj);
773 }
774 
775 static void kfd_remove_sysfs_node_entry(struct kfd_topology_device *dev)
776 {
777 	struct kfd_iolink_properties *iolink;
778 	struct kfd_cache_properties *cache;
779 	struct kfd_mem_properties *mem;
780 
781 	BUG_ON(!dev);
782 
783 	if (dev->kobj_iolink) {
784 		list_for_each_entry(iolink, &dev->io_link_props, list)
785 			if (iolink->kobj) {
786 				kfd_remove_sysfs_file(iolink->kobj,
787 							&iolink->attr);
788 				iolink->kobj = NULL;
789 			}
790 		kobject_del(dev->kobj_iolink);
791 		kobject_put(dev->kobj_iolink);
792 		dev->kobj_iolink = NULL;
793 	}
794 
795 	if (dev->kobj_cache) {
796 		list_for_each_entry(cache, &dev->cache_props, list)
797 			if (cache->kobj) {
798 				kfd_remove_sysfs_file(cache->kobj,
799 							&cache->attr);
800 				cache->kobj = NULL;
801 			}
802 		kobject_del(dev->kobj_cache);
803 		kobject_put(dev->kobj_cache);
804 		dev->kobj_cache = NULL;
805 	}
806 
807 	if (dev->kobj_mem) {
808 		list_for_each_entry(mem, &dev->mem_props, list)
809 			if (mem->kobj) {
810 				kfd_remove_sysfs_file(mem->kobj, &mem->attr);
811 				mem->kobj = NULL;
812 			}
813 		kobject_del(dev->kobj_mem);
814 		kobject_put(dev->kobj_mem);
815 		dev->kobj_mem = NULL;
816 	}
817 
818 	if (dev->kobj_node) {
819 		sysfs_remove_file(dev->kobj_node, &dev->attr_gpuid);
820 		sysfs_remove_file(dev->kobj_node, &dev->attr_name);
821 		sysfs_remove_file(dev->kobj_node, &dev->attr_props);
822 		kobject_del(dev->kobj_node);
823 		kobject_put(dev->kobj_node);
824 		dev->kobj_node = NULL;
825 	}
826 }
827 
828 static int kfd_build_sysfs_node_entry(struct kfd_topology_device *dev,
829 		uint32_t id)
830 {
831 	struct kfd_iolink_properties *iolink;
832 	struct kfd_cache_properties *cache;
833 	struct kfd_mem_properties *mem;
834 	int ret;
835 	uint32_t i;
836 
837 	BUG_ON(!dev);
838 
839 	/*
840 	 * Creating the sysfs folders
841 	 */
842 	BUG_ON(dev->kobj_node);
843 	dev->kobj_node = kfd_alloc_struct(dev->kobj_node);
844 	if (!dev->kobj_node)
845 		return -ENOMEM;
846 
847 	ret = kobject_init_and_add(dev->kobj_node, &node_type,
848 			sys_props.kobj_nodes, "%d", id);
849 	if (ret < 0)
850 		return ret;
851 
852 	dev->kobj_mem = kobject_create_and_add("mem_banks", dev->kobj_node);
853 	if (!dev->kobj_mem)
854 		return -ENOMEM;
855 
856 	dev->kobj_cache = kobject_create_and_add("caches", dev->kobj_node);
857 	if (!dev->kobj_cache)
858 		return -ENOMEM;
859 
860 	dev->kobj_iolink = kobject_create_and_add("io_links", dev->kobj_node);
861 	if (!dev->kobj_iolink)
862 		return -ENOMEM;
863 
864 	/*
865 	 * Creating sysfs files for node properties
866 	 */
867 	dev->attr_gpuid.name = "gpu_id";
868 	dev->attr_gpuid.mode = KFD_SYSFS_FILE_MODE;
869 	sysfs_attr_init(&dev->attr_gpuid);
870 	dev->attr_name.name = "name";
871 	dev->attr_name.mode = KFD_SYSFS_FILE_MODE;
872 	sysfs_attr_init(&dev->attr_name);
873 	dev->attr_props.name = "properties";
874 	dev->attr_props.mode = KFD_SYSFS_FILE_MODE;
875 	sysfs_attr_init(&dev->attr_props);
876 	ret = sysfs_create_file(dev->kobj_node, &dev->attr_gpuid);
877 	if (ret < 0)
878 		return ret;
879 	ret = sysfs_create_file(dev->kobj_node, &dev->attr_name);
880 	if (ret < 0)
881 		return ret;
882 	ret = sysfs_create_file(dev->kobj_node, &dev->attr_props);
883 	if (ret < 0)
884 		return ret;
885 
886 	i = 0;
887 	list_for_each_entry(mem, &dev->mem_props, list) {
888 		mem->kobj = kzalloc(sizeof(struct kobject), GFP_KERNEL);
889 		if (!mem->kobj)
890 			return -ENOMEM;
891 		ret = kobject_init_and_add(mem->kobj, &mem_type,
892 				dev->kobj_mem, "%d", i);
893 		if (ret < 0)
894 			return ret;
895 
896 		mem->attr.name = "properties";
897 		mem->attr.mode = KFD_SYSFS_FILE_MODE;
898 		sysfs_attr_init(&mem->attr);
899 		ret = sysfs_create_file(mem->kobj, &mem->attr);
900 		if (ret < 0)
901 			return ret;
902 		i++;
903 	}
904 
905 	i = 0;
906 	list_for_each_entry(cache, &dev->cache_props, list) {
907 		cache->kobj = kzalloc(sizeof(struct kobject), GFP_KERNEL);
908 		if (!cache->kobj)
909 			return -ENOMEM;
910 		ret = kobject_init_and_add(cache->kobj, &cache_type,
911 				dev->kobj_cache, "%d", i);
912 		if (ret < 0)
913 			return ret;
914 
915 		cache->attr.name = "properties";
916 		cache->attr.mode = KFD_SYSFS_FILE_MODE;
917 		sysfs_attr_init(&cache->attr);
918 		ret = sysfs_create_file(cache->kobj, &cache->attr);
919 		if (ret < 0)
920 			return ret;
921 		i++;
922 	}
923 
924 	i = 0;
925 	list_for_each_entry(iolink, &dev->io_link_props, list) {
926 		iolink->kobj = kzalloc(sizeof(struct kobject), GFP_KERNEL);
927 		if (!iolink->kobj)
928 			return -ENOMEM;
929 		ret = kobject_init_and_add(iolink->kobj, &iolink_type,
930 				dev->kobj_iolink, "%d", i);
931 		if (ret < 0)
932 			return ret;
933 
934 		iolink->attr.name = "properties";
935 		iolink->attr.mode = KFD_SYSFS_FILE_MODE;
936 		sysfs_attr_init(&iolink->attr);
937 		ret = sysfs_create_file(iolink->kobj, &iolink->attr);
938 		if (ret < 0)
939 			return ret;
940 		i++;
941 }
942 
943 	return 0;
944 }
945 
946 static int kfd_build_sysfs_node_tree(void)
947 {
948 	struct kfd_topology_device *dev;
949 	int ret;
950 	uint32_t i = 0;
951 
952 	list_for_each_entry(dev, &topology_device_list, list) {
953 		ret = kfd_build_sysfs_node_entry(dev, i);
954 		if (ret < 0)
955 			return ret;
956 		i++;
957 	}
958 
959 	return 0;
960 }
961 
962 static void kfd_remove_sysfs_node_tree(void)
963 {
964 	struct kfd_topology_device *dev;
965 
966 	list_for_each_entry(dev, &topology_device_list, list)
967 		kfd_remove_sysfs_node_entry(dev);
968 }
969 
970 static int kfd_topology_update_sysfs(void)
971 {
972 	int ret;
973 
974 	pr_info("Creating topology SYSFS entries\n");
975 	if (sys_props.kobj_topology == NULL) {
976 		sys_props.kobj_topology =
977 				kfd_alloc_struct(sys_props.kobj_topology);
978 		if (!sys_props.kobj_topology)
979 			return -ENOMEM;
980 
981 		ret = kobject_init_and_add(sys_props.kobj_topology,
982 				&sysprops_type,  &kfd_device->kobj,
983 				"topology");
984 		if (ret < 0)
985 			return ret;
986 
987 		sys_props.kobj_nodes = kobject_create_and_add("nodes",
988 				sys_props.kobj_topology);
989 		if (!sys_props.kobj_nodes)
990 			return -ENOMEM;
991 
992 		sys_props.attr_genid.name = "generation_id";
993 		sys_props.attr_genid.mode = KFD_SYSFS_FILE_MODE;
994 		sysfs_attr_init(&sys_props.attr_genid);
995 		ret = sysfs_create_file(sys_props.kobj_topology,
996 				&sys_props.attr_genid);
997 		if (ret < 0)
998 			return ret;
999 
1000 		sys_props.attr_props.name = "system_properties";
1001 		sys_props.attr_props.mode = KFD_SYSFS_FILE_MODE;
1002 		sysfs_attr_init(&sys_props.attr_props);
1003 		ret = sysfs_create_file(sys_props.kobj_topology,
1004 				&sys_props.attr_props);
1005 		if (ret < 0)
1006 			return ret;
1007 	}
1008 
1009 	kfd_remove_sysfs_node_tree();
1010 
1011 	return kfd_build_sysfs_node_tree();
1012 }
1013 
1014 static void kfd_topology_release_sysfs(void)
1015 {
1016 	kfd_remove_sysfs_node_tree();
1017 	if (sys_props.kobj_topology) {
1018 		sysfs_remove_file(sys_props.kobj_topology,
1019 				&sys_props.attr_genid);
1020 		sysfs_remove_file(sys_props.kobj_topology,
1021 				&sys_props.attr_props);
1022 		if (sys_props.kobj_nodes) {
1023 			kobject_del(sys_props.kobj_nodes);
1024 			kobject_put(sys_props.kobj_nodes);
1025 			sys_props.kobj_nodes = NULL;
1026 		}
1027 		kobject_del(sys_props.kobj_topology);
1028 		kobject_put(sys_props.kobj_topology);
1029 		sys_props.kobj_topology = NULL;
1030 	}
1031 }
1032 
1033 int kfd_topology_init(void)
1034 {
1035 	void *crat_image = NULL;
1036 	size_t image_size = 0;
1037 	int ret;
1038 
1039 	/*
1040 	 * Initialize the head for the topology device list
1041 	 */
1042 	INIT_LIST_HEAD(&topology_device_list);
1043 	init_rwsem(&topology_lock);
1044 	topology_crat_parsed = 0;
1045 
1046 	memset(&sys_props, 0, sizeof(sys_props));
1047 
1048 	/*
1049 	 * Get the CRAT image from the ACPI
1050 	 */
1051 	ret = kfd_topology_get_crat_acpi(crat_image, &image_size);
1052 	if (ret == 0 && image_size > 0) {
1053 		pr_info("Found CRAT image with size=%zd\n", image_size);
1054 		crat_image = kmalloc(image_size, GFP_KERNEL);
1055 		if (!crat_image) {
1056 			ret = -ENOMEM;
1057 			pr_err("No memory for allocating CRAT image\n");
1058 			goto err;
1059 		}
1060 		ret = kfd_topology_get_crat_acpi(crat_image, &image_size);
1061 
1062 		if (ret == 0) {
1063 			down_write(&topology_lock);
1064 			ret = kfd_parse_crat_table(crat_image);
1065 			if (ret == 0)
1066 				ret = kfd_topology_update_sysfs();
1067 			up_write(&topology_lock);
1068 		} else {
1069 			pr_err("Couldn't get CRAT table size from ACPI\n");
1070 		}
1071 		kfree(crat_image);
1072 	} else if (ret == -ENODATA) {
1073 		ret = 0;
1074 	} else {
1075 		pr_err("Couldn't get CRAT table size from ACPI\n");
1076 	}
1077 
1078 err:
1079 	pr_info("Finished initializing topology ret=%d\n", ret);
1080 	return ret;
1081 }
1082 
1083 void kfd_topology_shutdown(void)
1084 {
1085 	kfd_topology_release_sysfs();
1086 	kfd_release_live_view();
1087 }
1088 
1089 static void kfd_debug_print_topology(void)
1090 {
1091 	struct kfd_topology_device *dev;
1092 	uint32_t i = 0;
1093 
1094 	pr_info("DEBUG PRINT OF TOPOLOGY:");
1095 	list_for_each_entry(dev, &topology_device_list, list) {
1096 		pr_info("Node: %d\n", i);
1097 		pr_info("\tGPU assigned: %s\n", (dev->gpu ? "yes" : "no"));
1098 		pr_info("\tCPU count: %d\n", dev->node_props.cpu_cores_count);
1099 		pr_info("\tSIMD count: %d", dev->node_props.simd_count);
1100 		i++;
1101 	}
1102 }
1103 
1104 static uint32_t kfd_generate_gpu_id(struct kfd_dev *gpu)
1105 {
1106 	uint32_t hashout;
1107 	uint32_t buf[7];
1108 	int i;
1109 
1110 	if (!gpu)
1111 		return 0;
1112 
1113 	buf[0] = gpu->pdev->devfn;
1114 	buf[1] = gpu->pdev->subsystem_vendor;
1115 	buf[2] = gpu->pdev->subsystem_device;
1116 	buf[3] = gpu->pdev->device;
1117 	buf[4] = gpu->pdev->bus->number;
1118 	buf[5] = (uint32_t)(gpu->kfd2kgd->get_vmem_size(gpu->kgd)
1119 			& 0xffffffff);
1120 	buf[6] = (uint32_t)(gpu->kfd2kgd->get_vmem_size(gpu->kgd) >> 32);
1121 
1122 	for (i = 0, hashout = 0; i < 7; i++)
1123 		hashout ^= hash_32(buf[i], KFD_GPU_ID_HASH_WIDTH);
1124 
1125 	return hashout;
1126 }
1127 
1128 static struct kfd_topology_device *kfd_assign_gpu(struct kfd_dev *gpu)
1129 {
1130 	struct kfd_topology_device *dev;
1131 	struct kfd_topology_device *out_dev = NULL;
1132 
1133 	BUG_ON(!gpu);
1134 
1135 	list_for_each_entry(dev, &topology_device_list, list)
1136 		if (dev->gpu == NULL && dev->node_props.simd_count > 0) {
1137 			dev->gpu = gpu;
1138 			out_dev = dev;
1139 			break;
1140 		}
1141 
1142 	return out_dev;
1143 }
1144 
1145 static void kfd_notify_gpu_change(uint32_t gpu_id, int arrival)
1146 {
1147 	/*
1148 	 * TODO: Generate an event for thunk about the arrival/removal
1149 	 * of the GPU
1150 	 */
1151 }
1152 
1153 int kfd_topology_add_device(struct kfd_dev *gpu)
1154 {
1155 	uint32_t gpu_id;
1156 	struct kfd_topology_device *dev;
1157 	int res;
1158 
1159 	BUG_ON(!gpu);
1160 
1161 	gpu_id = kfd_generate_gpu_id(gpu);
1162 
1163 	pr_debug("kfd: Adding new GPU (ID: 0x%x) to topology\n", gpu_id);
1164 
1165 	down_write(&topology_lock);
1166 	/*
1167 	 * Try to assign the GPU to existing topology device (generated from
1168 	 * CRAT table
1169 	 */
1170 	dev = kfd_assign_gpu(gpu);
1171 	if (!dev) {
1172 		pr_info("GPU was not found in the current topology. Extending.\n");
1173 		kfd_debug_print_topology();
1174 		dev = kfd_create_topology_device();
1175 		if (!dev) {
1176 			res = -ENOMEM;
1177 			goto err;
1178 		}
1179 		dev->gpu = gpu;
1180 
1181 		/*
1182 		 * TODO: Make a call to retrieve topology information from the
1183 		 * GPU vBIOS
1184 		 */
1185 
1186 		/*
1187 		 * Update the SYSFS tree, since we added another topology device
1188 		 */
1189 		if (kfd_topology_update_sysfs() < 0)
1190 			kfd_topology_release_sysfs();
1191 
1192 	}
1193 
1194 	dev->gpu_id = gpu_id;
1195 	gpu->id = gpu_id;
1196 	dev->node_props.vendor_id = gpu->pdev->vendor;
1197 	dev->node_props.device_id = gpu->pdev->device;
1198 	dev->node_props.location_id = (gpu->pdev->bus->number << 24) +
1199 			(gpu->pdev->devfn & 0xffffff);
1200 	/*
1201 	 * TODO: Retrieve max engine clock values from KGD
1202 	 */
1203 
1204 	if (dev->gpu->device_info->asic_family == CHIP_CARRIZO) {
1205 		dev->node_props.capability |= HSA_CAP_DOORBELL_PACKET_TYPE;
1206 		pr_info("amdkfd: adding doorbell packet type capability\n");
1207 	}
1208 
1209 	res = 0;
1210 
1211 err:
1212 	up_write(&topology_lock);
1213 
1214 	if (res == 0)
1215 		kfd_notify_gpu_change(gpu_id, 1);
1216 
1217 	return res;
1218 }
1219 
1220 int kfd_topology_remove_device(struct kfd_dev *gpu)
1221 {
1222 	struct kfd_topology_device *dev;
1223 	uint32_t gpu_id;
1224 	int res = -ENODEV;
1225 
1226 	BUG_ON(!gpu);
1227 
1228 	down_write(&topology_lock);
1229 
1230 	list_for_each_entry(dev, &topology_device_list, list)
1231 		if (dev->gpu == gpu) {
1232 			gpu_id = dev->gpu_id;
1233 			kfd_remove_sysfs_node_entry(dev);
1234 			kfd_release_topology_device(dev);
1235 			res = 0;
1236 			if (kfd_topology_update_sysfs() < 0)
1237 				kfd_topology_release_sysfs();
1238 			break;
1239 		}
1240 
1241 	up_write(&topology_lock);
1242 
1243 	if (res == 0)
1244 		kfd_notify_gpu_change(gpu_id, 0);
1245 
1246 	return res;
1247 }
1248 
1249 /*
1250  * When idx is out of bounds, the function will return NULL
1251  */
1252 struct kfd_dev *kfd_topology_enum_kfd_devices(uint8_t idx)
1253 {
1254 
1255 	struct kfd_topology_device *top_dev;
1256 	struct kfd_dev *device = NULL;
1257 	uint8_t device_idx = 0;
1258 
1259 	down_read(&topology_lock);
1260 
1261 	list_for_each_entry(top_dev, &topology_device_list, list) {
1262 		if (device_idx == idx) {
1263 			device = top_dev->gpu;
1264 			break;
1265 		}
1266 
1267 		device_idx++;
1268 	}
1269 
1270 	up_read(&topology_lock);
1271 
1272 	return device;
1273 
1274 }
1275