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