1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2020 HiSilicon Limited.
4 */
5
6 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
7
8 #include <linux/debugfs.h>
9 #include <linux/delay.h>
10 #include <linux/device.h>
11 #include <linux/dma-mapping.h>
12 #include <linux/kernel.h>
13 #include <linux/kthread.h>
14 #include <linux/math64.h>
15 #include <linux/module.h>
16 #include <linux/pci.h>
17 #include <linux/platform_device.h>
18 #include <linux/slab.h>
19 #include <linux/timekeeping.h>
20
21 #define DMA_MAP_BENCHMARK _IOWR('d', 1, struct map_benchmark)
22 #define DMA_MAP_MAX_THREADS 1024
23 #define DMA_MAP_MAX_SECONDS 300
24 #define DMA_MAP_MAX_TRANS_DELAY (10 * NSEC_PER_MSEC)
25
26 #define DMA_MAP_BIDIRECTIONAL 0
27 #define DMA_MAP_TO_DEVICE 1
28 #define DMA_MAP_FROM_DEVICE 2
29
30 struct map_benchmark {
31 __u64 avg_map_100ns; /* average map latency in 100ns */
32 __u64 map_stddev; /* standard deviation of map latency */
33 __u64 avg_unmap_100ns; /* as above */
34 __u64 unmap_stddev;
35 __u32 threads; /* how many threads will do map/unmap in parallel */
36 __u32 seconds; /* how long the test will last */
37 __s32 node; /* which numa node this benchmark will run on */
38 __u32 dma_bits; /* DMA addressing capability */
39 __u32 dma_dir; /* DMA data direction */
40 __u32 dma_trans_ns; /* time for DMA transmission in ns */
41 __u32 granule; /* how many PAGE_SIZE will do map/unmap once a time */
42 __u8 expansion[76]; /* For future use */
43 };
44
45 struct map_benchmark_data {
46 struct map_benchmark bparam;
47 struct device *dev;
48 struct dentry *debugfs;
49 enum dma_data_direction dir;
50 atomic64_t sum_map_100ns;
51 atomic64_t sum_unmap_100ns;
52 atomic64_t sum_sq_map;
53 atomic64_t sum_sq_unmap;
54 atomic64_t loops;
55 };
56
map_benchmark_thread(void * data)57 static int map_benchmark_thread(void *data)
58 {
59 void *buf;
60 dma_addr_t dma_addr;
61 struct map_benchmark_data *map = data;
62 int npages = map->bparam.granule;
63 u64 size = npages * PAGE_SIZE;
64 int ret = 0;
65
66 buf = alloc_pages_exact(size, GFP_KERNEL);
67 if (!buf)
68 return -ENOMEM;
69
70 while (!kthread_should_stop()) {
71 u64 map_100ns, unmap_100ns, map_sq, unmap_sq;
72 ktime_t map_stime, map_etime, unmap_stime, unmap_etime;
73 ktime_t map_delta, unmap_delta;
74
75 /*
76 * for a non-coherent device, if we don't stain them in the
77 * cache, this will give an underestimate of the real-world
78 * overhead of BIDIRECTIONAL or TO_DEVICE mappings;
79 * 66 means evertything goes well! 66 is lucky.
80 */
81 if (map->dir != DMA_FROM_DEVICE)
82 memset(buf, 0x66, size);
83
84 map_stime = ktime_get();
85 dma_addr = dma_map_single(map->dev, buf, size, map->dir);
86 if (unlikely(dma_mapping_error(map->dev, dma_addr))) {
87 pr_err("dma_map_single failed on %s\n",
88 dev_name(map->dev));
89 ret = -ENOMEM;
90 goto out;
91 }
92 map_etime = ktime_get();
93 map_delta = ktime_sub(map_etime, map_stime);
94
95 /* Pretend DMA is transmitting */
96 ndelay(map->bparam.dma_trans_ns);
97
98 unmap_stime = ktime_get();
99 dma_unmap_single(map->dev, dma_addr, size, map->dir);
100 unmap_etime = ktime_get();
101 unmap_delta = ktime_sub(unmap_etime, unmap_stime);
102
103 /* calculate sum and sum of squares */
104
105 map_100ns = div64_ul(map_delta, 100);
106 unmap_100ns = div64_ul(unmap_delta, 100);
107 map_sq = map_100ns * map_100ns;
108 unmap_sq = unmap_100ns * unmap_100ns;
109
110 atomic64_add(map_100ns, &map->sum_map_100ns);
111 atomic64_add(unmap_100ns, &map->sum_unmap_100ns);
112 atomic64_add(map_sq, &map->sum_sq_map);
113 atomic64_add(unmap_sq, &map->sum_sq_unmap);
114 atomic64_inc(&map->loops);
115 }
116
117 out:
118 free_pages_exact(buf, size);
119 return ret;
120 }
121
do_map_benchmark(struct map_benchmark_data * map)122 static int do_map_benchmark(struct map_benchmark_data *map)
123 {
124 struct task_struct **tsk;
125 int threads = map->bparam.threads;
126 int node = map->bparam.node;
127 const cpumask_t *cpu_mask = cpumask_of_node(node);
128 u64 loops;
129 int ret = 0;
130 int i;
131
132 tsk = kmalloc_array(threads, sizeof(*tsk), GFP_KERNEL);
133 if (!tsk)
134 return -ENOMEM;
135
136 get_device(map->dev);
137
138 for (i = 0; i < threads; i++) {
139 tsk[i] = kthread_create_on_node(map_benchmark_thread, map,
140 map->bparam.node, "dma-map-benchmark/%d", i);
141 if (IS_ERR(tsk[i])) {
142 pr_err("create dma_map thread failed\n");
143 ret = PTR_ERR(tsk[i]);
144 goto out;
145 }
146
147 if (node != NUMA_NO_NODE)
148 kthread_bind_mask(tsk[i], cpu_mask);
149 }
150
151 /* clear the old value in the previous benchmark */
152 atomic64_set(&map->sum_map_100ns, 0);
153 atomic64_set(&map->sum_unmap_100ns, 0);
154 atomic64_set(&map->sum_sq_map, 0);
155 atomic64_set(&map->sum_sq_unmap, 0);
156 atomic64_set(&map->loops, 0);
157
158 for (i = 0; i < threads; i++) {
159 get_task_struct(tsk[i]);
160 wake_up_process(tsk[i]);
161 }
162
163 msleep_interruptible(map->bparam.seconds * 1000);
164
165 /* wait for the completion of benchmark threads */
166 for (i = 0; i < threads; i++) {
167 ret = kthread_stop(tsk[i]);
168 if (ret)
169 goto out;
170 }
171
172 loops = atomic64_read(&map->loops);
173 if (likely(loops > 0)) {
174 u64 map_variance, unmap_variance;
175 u64 sum_map = atomic64_read(&map->sum_map_100ns);
176 u64 sum_unmap = atomic64_read(&map->sum_unmap_100ns);
177 u64 sum_sq_map = atomic64_read(&map->sum_sq_map);
178 u64 sum_sq_unmap = atomic64_read(&map->sum_sq_unmap);
179
180 /* average latency */
181 map->bparam.avg_map_100ns = div64_u64(sum_map, loops);
182 map->bparam.avg_unmap_100ns = div64_u64(sum_unmap, loops);
183
184 /* standard deviation of latency */
185 map_variance = div64_u64(sum_sq_map, loops) -
186 map->bparam.avg_map_100ns *
187 map->bparam.avg_map_100ns;
188 unmap_variance = div64_u64(sum_sq_unmap, loops) -
189 map->bparam.avg_unmap_100ns *
190 map->bparam.avg_unmap_100ns;
191 map->bparam.map_stddev = int_sqrt64(map_variance);
192 map->bparam.unmap_stddev = int_sqrt64(unmap_variance);
193 }
194
195 out:
196 for (i = 0; i < threads; i++)
197 put_task_struct(tsk[i]);
198 put_device(map->dev);
199 kfree(tsk);
200 return ret;
201 }
202
map_benchmark_ioctl(struct file * file,unsigned int cmd,unsigned long arg)203 static long map_benchmark_ioctl(struct file *file, unsigned int cmd,
204 unsigned long arg)
205 {
206 struct map_benchmark_data *map = file->private_data;
207 void __user *argp = (void __user *)arg;
208 u64 old_dma_mask;
209 int ret;
210
211 if (copy_from_user(&map->bparam, argp, sizeof(map->bparam)))
212 return -EFAULT;
213
214 switch (cmd) {
215 case DMA_MAP_BENCHMARK:
216 if (map->bparam.threads == 0 ||
217 map->bparam.threads > DMA_MAP_MAX_THREADS) {
218 pr_err("invalid thread number\n");
219 return -EINVAL;
220 }
221
222 if (map->bparam.seconds == 0 ||
223 map->bparam.seconds > DMA_MAP_MAX_SECONDS) {
224 pr_err("invalid duration seconds\n");
225 return -EINVAL;
226 }
227
228 if (map->bparam.dma_trans_ns > DMA_MAP_MAX_TRANS_DELAY) {
229 pr_err("invalid transmission delay\n");
230 return -EINVAL;
231 }
232
233 if (map->bparam.node != NUMA_NO_NODE &&
234 !node_possible(map->bparam.node)) {
235 pr_err("invalid numa node\n");
236 return -EINVAL;
237 }
238
239 if (map->bparam.granule < 1 || map->bparam.granule > 1024) {
240 pr_err("invalid granule size\n");
241 return -EINVAL;
242 }
243
244 switch (map->bparam.dma_dir) {
245 case DMA_MAP_BIDIRECTIONAL:
246 map->dir = DMA_BIDIRECTIONAL;
247 break;
248 case DMA_MAP_FROM_DEVICE:
249 map->dir = DMA_FROM_DEVICE;
250 break;
251 case DMA_MAP_TO_DEVICE:
252 map->dir = DMA_TO_DEVICE;
253 break;
254 default:
255 pr_err("invalid DMA direction\n");
256 return -EINVAL;
257 }
258
259 old_dma_mask = dma_get_mask(map->dev);
260
261 ret = dma_set_mask(map->dev,
262 DMA_BIT_MASK(map->bparam.dma_bits));
263 if (ret) {
264 pr_err("failed to set dma_mask on device %s\n",
265 dev_name(map->dev));
266 return -EINVAL;
267 }
268
269 ret = do_map_benchmark(map);
270
271 /*
272 * restore the original dma_mask as many devices' dma_mask are
273 * set by architectures, acpi, busses. When we bind them back
274 * to their original drivers, those drivers shouldn't see
275 * dma_mask changed by benchmark
276 */
277 dma_set_mask(map->dev, old_dma_mask);
278 break;
279 default:
280 return -EINVAL;
281 }
282
283 if (copy_to_user(argp, &map->bparam, sizeof(map->bparam)))
284 return -EFAULT;
285
286 return ret;
287 }
288
289 static const struct file_operations map_benchmark_fops = {
290 .open = simple_open,
291 .unlocked_ioctl = map_benchmark_ioctl,
292 };
293
map_benchmark_remove_debugfs(void * data)294 static void map_benchmark_remove_debugfs(void *data)
295 {
296 struct map_benchmark_data *map = (struct map_benchmark_data *)data;
297
298 debugfs_remove(map->debugfs);
299 }
300
__map_benchmark_probe(struct device * dev)301 static int __map_benchmark_probe(struct device *dev)
302 {
303 struct dentry *entry;
304 struct map_benchmark_data *map;
305 int ret;
306
307 map = devm_kzalloc(dev, sizeof(*map), GFP_KERNEL);
308 if (!map)
309 return -ENOMEM;
310 map->dev = dev;
311
312 ret = devm_add_action(dev, map_benchmark_remove_debugfs, map);
313 if (ret) {
314 pr_err("Can't add debugfs remove action\n");
315 return ret;
316 }
317
318 /*
319 * we only permit a device bound with this driver, 2nd probe
320 * will fail
321 */
322 entry = debugfs_create_file("dma_map_benchmark", 0600, NULL, map,
323 &map_benchmark_fops);
324 if (IS_ERR(entry))
325 return PTR_ERR(entry);
326 map->debugfs = entry;
327
328 return 0;
329 }
330
map_benchmark_platform_probe(struct platform_device * pdev)331 static int map_benchmark_platform_probe(struct platform_device *pdev)
332 {
333 return __map_benchmark_probe(&pdev->dev);
334 }
335
336 static struct platform_driver map_benchmark_platform_driver = {
337 .driver = {
338 .name = "dma_map_benchmark",
339 },
340 .probe = map_benchmark_platform_probe,
341 };
342
343 static int
map_benchmark_pci_probe(struct pci_dev * pdev,const struct pci_device_id * id)344 map_benchmark_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
345 {
346 return __map_benchmark_probe(&pdev->dev);
347 }
348
349 static struct pci_driver map_benchmark_pci_driver = {
350 .name = "dma_map_benchmark",
351 .probe = map_benchmark_pci_probe,
352 };
353
map_benchmark_init(void)354 static int __init map_benchmark_init(void)
355 {
356 int ret;
357
358 ret = pci_register_driver(&map_benchmark_pci_driver);
359 if (ret)
360 return ret;
361
362 ret = platform_driver_register(&map_benchmark_platform_driver);
363 if (ret) {
364 pci_unregister_driver(&map_benchmark_pci_driver);
365 return ret;
366 }
367
368 return 0;
369 }
370
map_benchmark_cleanup(void)371 static void __exit map_benchmark_cleanup(void)
372 {
373 platform_driver_unregister(&map_benchmark_platform_driver);
374 pci_unregister_driver(&map_benchmark_pci_driver);
375 }
376
377 module_init(map_benchmark_init);
378 module_exit(map_benchmark_cleanup);
379
380 MODULE_AUTHOR("Barry Song <song.bao.hua@hisilicon.com>");
381 MODULE_DESCRIPTION("dma_map benchmark driver");
382 MODULE_LICENSE("GPL");
383
