1 /*
2 * Copyright 2014 IBM Corp.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
8 */
9
10 #include <linux/spinlock.h>
11 #include <linux/module.h>
12 #include <linux/export.h>
13 #include <linux/kernel.h>
14 #include <linux/bitmap.h>
15 #include <linux/sched.h>
16 #include <linux/poll.h>
17 #include <linux/pid.h>
18 #include <linux/fs.h>
19 #include <linux/mm.h>
20 #include <linux/slab.h>
21 #include <asm/cputable.h>
22 #include <asm/current.h>
23 #include <asm/copro.h>
24
25 #include "cxl.h"
26
27 #define CXL_NUM_MINORS 256 /* Total to reserve */
28 #define CXL_DEV_MINORS 13 /* 1 control + 4 AFUs * 3 (dedicated/master/shared) */
29
30 #define CXL_CARD_MINOR(adapter) (adapter->adapter_num * CXL_DEV_MINORS)
31 #define CXL_AFU_MINOR_D(afu) (CXL_CARD_MINOR(afu->adapter) + 1 + (3 * afu->slice))
32 #define CXL_AFU_MINOR_M(afu) (CXL_AFU_MINOR_D(afu) + 1)
33 #define CXL_AFU_MINOR_S(afu) (CXL_AFU_MINOR_D(afu) + 2)
34 #define CXL_AFU_MKDEV_D(afu) MKDEV(MAJOR(cxl_dev), CXL_AFU_MINOR_D(afu))
35 #define CXL_AFU_MKDEV_M(afu) MKDEV(MAJOR(cxl_dev), CXL_AFU_MINOR_M(afu))
36 #define CXL_AFU_MKDEV_S(afu) MKDEV(MAJOR(cxl_dev), CXL_AFU_MINOR_S(afu))
37
38 #define CXL_DEVT_ADAPTER(dev) (MINOR(dev) / CXL_DEV_MINORS)
39 #define CXL_DEVT_AFU(dev) ((MINOR(dev) % CXL_DEV_MINORS - 1) / 3)
40
41 #define CXL_DEVT_IS_CARD(dev) (MINOR(dev) % CXL_DEV_MINORS == 0)
42
43 static dev_t cxl_dev;
44
45 static struct class *cxl_class;
46
__afu_open(struct inode * inode,struct file * file,bool master)47 static int __afu_open(struct inode *inode, struct file *file, bool master)
48 {
49 struct cxl *adapter;
50 struct cxl_afu *afu;
51 struct cxl_context *ctx;
52 int adapter_num = CXL_DEVT_ADAPTER(inode->i_rdev);
53 int slice = CXL_DEVT_AFU(inode->i_rdev);
54 int rc = -ENODEV;
55
56 pr_devel("afu_open afu%i.%i\n", slice, adapter_num);
57
58 if (!(adapter = get_cxl_adapter(adapter_num)))
59 return -ENODEV;
60
61 if (slice > adapter->slices)
62 goto err_put_adapter;
63
64 spin_lock(&adapter->afu_list_lock);
65 if (!(afu = adapter->afu[slice])) {
66 spin_unlock(&adapter->afu_list_lock);
67 goto err_put_adapter;
68 }
69 get_device(&afu->dev);
70 spin_unlock(&adapter->afu_list_lock);
71
72 if (!afu->current_mode)
73 goto err_put_afu;
74
75 if (!(ctx = cxl_context_alloc())) {
76 rc = -ENOMEM;
77 goto err_put_afu;
78 }
79
80 if ((rc = cxl_context_init(ctx, afu, master, inode->i_mapping)))
81 goto err_put_afu;
82
83 pr_devel("afu_open pe: %i\n", ctx->pe);
84 file->private_data = ctx;
85 cxl_ctx_get();
86
87 /* Our ref on the AFU will now hold the adapter */
88 put_device(&adapter->dev);
89
90 return 0;
91
92 err_put_afu:
93 put_device(&afu->dev);
94 err_put_adapter:
95 put_device(&adapter->dev);
96 return rc;
97 }
afu_open(struct inode * inode,struct file * file)98 static int afu_open(struct inode *inode, struct file *file)
99 {
100 return __afu_open(inode, file, false);
101 }
102
afu_master_open(struct inode * inode,struct file * file)103 static int afu_master_open(struct inode *inode, struct file *file)
104 {
105 return __afu_open(inode, file, true);
106 }
107
afu_release(struct inode * inode,struct file * file)108 static int afu_release(struct inode *inode, struct file *file)
109 {
110 struct cxl_context *ctx = file->private_data;
111
112 pr_devel("%s: closing cxl file descriptor. pe: %i\n",
113 __func__, ctx->pe);
114 cxl_context_detach(ctx);
115
116 mutex_lock(&ctx->mapping_lock);
117 ctx->mapping = NULL;
118 mutex_unlock(&ctx->mapping_lock);
119
120 put_device(&ctx->afu->dev);
121
122 /*
123 * At this this point all bottom halfs have finished and we should be
124 * getting no more IRQs from the hardware for this context. Once it's
125 * removed from the IDR (and RCU synchronised) it's safe to free the
126 * sstp and context.
127 */
128 cxl_context_free(ctx);
129
130 cxl_ctx_put();
131 return 0;
132 }
133
afu_ioctl_start_work(struct cxl_context * ctx,struct cxl_ioctl_start_work __user * uwork)134 static long afu_ioctl_start_work(struct cxl_context *ctx,
135 struct cxl_ioctl_start_work __user *uwork)
136 {
137 struct cxl_ioctl_start_work work;
138 u64 amr = 0;
139 int rc;
140
141 pr_devel("%s: pe: %i\n", __func__, ctx->pe);
142
143 mutex_lock(&ctx->status_mutex);
144 if (ctx->status != OPENED) {
145 rc = -EIO;
146 goto out;
147 }
148
149 if (copy_from_user(&work, uwork,
150 sizeof(struct cxl_ioctl_start_work))) {
151 rc = -EFAULT;
152 goto out;
153 }
154
155 /*
156 * if any of the reserved fields are set or any of the unused
157 * flags are set it's invalid
158 */
159 if (work.reserved1 || work.reserved2 || work.reserved3 ||
160 work.reserved4 || work.reserved5 || work.reserved6 ||
161 (work.flags & ~CXL_START_WORK_ALL)) {
162 rc = -EINVAL;
163 goto out;
164 }
165
166 if (!(work.flags & CXL_START_WORK_NUM_IRQS))
167 work.num_interrupts = ctx->afu->pp_irqs;
168 else if ((work.num_interrupts < ctx->afu->pp_irqs) ||
169 (work.num_interrupts > ctx->afu->irqs_max)) {
170 rc = -EINVAL;
171 goto out;
172 }
173 if ((rc = afu_register_irqs(ctx, work.num_interrupts)))
174 goto out;
175
176 if (work.flags & CXL_START_WORK_AMR)
177 amr = work.amr & mfspr(SPRN_UAMOR);
178
179 /*
180 * We grab the PID here and not in the file open to allow for the case
181 * where a process (master, some daemon, etc) has opened the chardev on
182 * behalf of another process, so the AFU's mm gets bound to the process
183 * that performs this ioctl and not the process that opened the file.
184 */
185 ctx->pid = get_pid(get_task_pid(current, PIDTYPE_PID));
186
187 if ((rc = cxl_attach_process(ctx, false, work.work_element_descriptor,
188 amr)))
189 goto out;
190
191 ctx->status = STARTED;
192 rc = 0;
193 out:
194 mutex_unlock(&ctx->status_mutex);
195 return rc;
196 }
afu_ioctl_process_element(struct cxl_context * ctx,int __user * upe)197 static long afu_ioctl_process_element(struct cxl_context *ctx,
198 int __user *upe)
199 {
200 pr_devel("%s: pe: %i\n", __func__, ctx->pe);
201
202 if (copy_to_user(upe, &ctx->pe, sizeof(__u32)))
203 return -EFAULT;
204
205 return 0;
206 }
207
afu_ioctl(struct file * file,unsigned int cmd,unsigned long arg)208 static long afu_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
209 {
210 struct cxl_context *ctx = file->private_data;
211
212 if (ctx->status == CLOSED)
213 return -EIO;
214
215 pr_devel("afu_ioctl\n");
216 switch (cmd) {
217 case CXL_IOCTL_START_WORK:
218 return afu_ioctl_start_work(ctx, (struct cxl_ioctl_start_work __user *)arg);
219 case CXL_IOCTL_GET_PROCESS_ELEMENT:
220 return afu_ioctl_process_element(ctx, (__u32 __user *)arg);
221 }
222 return -EINVAL;
223 }
224
afu_compat_ioctl(struct file * file,unsigned int cmd,unsigned long arg)225 static long afu_compat_ioctl(struct file *file, unsigned int cmd,
226 unsigned long arg)
227 {
228 return afu_ioctl(file, cmd, arg);
229 }
230
afu_mmap(struct file * file,struct vm_area_struct * vm)231 static int afu_mmap(struct file *file, struct vm_area_struct *vm)
232 {
233 struct cxl_context *ctx = file->private_data;
234
235 /* AFU must be started before we can MMIO */
236 if (ctx->status != STARTED)
237 return -EIO;
238
239 return cxl_context_iomap(ctx, vm);
240 }
241
afu_poll(struct file * file,struct poll_table_struct * poll)242 static unsigned int afu_poll(struct file *file, struct poll_table_struct *poll)
243 {
244 struct cxl_context *ctx = file->private_data;
245 int mask = 0;
246 unsigned long flags;
247
248
249 poll_wait(file, &ctx->wq, poll);
250
251 pr_devel("afu_poll wait done pe: %i\n", ctx->pe);
252
253 spin_lock_irqsave(&ctx->lock, flags);
254 if (ctx->pending_irq || ctx->pending_fault ||
255 ctx->pending_afu_err)
256 mask |= POLLIN | POLLRDNORM;
257 else if (ctx->status == CLOSED)
258 /* Only error on closed when there are no futher events pending
259 */
260 mask |= POLLERR;
261 spin_unlock_irqrestore(&ctx->lock, flags);
262
263 pr_devel("afu_poll pe: %i returning %#x\n", ctx->pe, mask);
264
265 return mask;
266 }
267
ctx_event_pending(struct cxl_context * ctx)268 static inline int ctx_event_pending(struct cxl_context *ctx)
269 {
270 return (ctx->pending_irq || ctx->pending_fault ||
271 ctx->pending_afu_err || (ctx->status == CLOSED));
272 }
273
afu_read(struct file * file,char __user * buf,size_t count,loff_t * off)274 static ssize_t afu_read(struct file *file, char __user *buf, size_t count,
275 loff_t *off)
276 {
277 struct cxl_context *ctx = file->private_data;
278 struct cxl_event event;
279 unsigned long flags;
280 int rc;
281 DEFINE_WAIT(wait);
282
283 if (count < CXL_READ_MIN_SIZE)
284 return -EINVAL;
285
286 spin_lock_irqsave(&ctx->lock, flags);
287
288 for (;;) {
289 prepare_to_wait(&ctx->wq, &wait, TASK_INTERRUPTIBLE);
290 if (ctx_event_pending(ctx))
291 break;
292
293 if (file->f_flags & O_NONBLOCK) {
294 rc = -EAGAIN;
295 goto out;
296 }
297
298 if (signal_pending(current)) {
299 rc = -ERESTARTSYS;
300 goto out;
301 }
302
303 spin_unlock_irqrestore(&ctx->lock, flags);
304 pr_devel("afu_read going to sleep...\n");
305 schedule();
306 pr_devel("afu_read woken up\n");
307 spin_lock_irqsave(&ctx->lock, flags);
308 }
309
310 finish_wait(&ctx->wq, &wait);
311
312 memset(&event, 0, sizeof(event));
313 event.header.process_element = ctx->pe;
314 event.header.size = sizeof(struct cxl_event_header);
315 if (ctx->pending_irq) {
316 pr_devel("afu_read delivering AFU interrupt\n");
317 event.header.size += sizeof(struct cxl_event_afu_interrupt);
318 event.header.type = CXL_EVENT_AFU_INTERRUPT;
319 event.irq.irq = find_first_bit(ctx->irq_bitmap, ctx->irq_count) + 1;
320 clear_bit(event.irq.irq - 1, ctx->irq_bitmap);
321 if (bitmap_empty(ctx->irq_bitmap, ctx->irq_count))
322 ctx->pending_irq = false;
323 } else if (ctx->pending_fault) {
324 pr_devel("afu_read delivering data storage fault\n");
325 event.header.size += sizeof(struct cxl_event_data_storage);
326 event.header.type = CXL_EVENT_DATA_STORAGE;
327 event.fault.addr = ctx->fault_addr;
328 event.fault.dsisr = ctx->fault_dsisr;
329 ctx->pending_fault = false;
330 } else if (ctx->pending_afu_err) {
331 pr_devel("afu_read delivering afu error\n");
332 event.header.size += sizeof(struct cxl_event_afu_error);
333 event.header.type = CXL_EVENT_AFU_ERROR;
334 event.afu_error.error = ctx->afu_err;
335 ctx->pending_afu_err = false;
336 } else if (ctx->status == CLOSED) {
337 pr_devel("afu_read fatal error\n");
338 spin_unlock_irqrestore(&ctx->lock, flags);
339 return -EIO;
340 } else
341 WARN(1, "afu_read must be buggy\n");
342
343 spin_unlock_irqrestore(&ctx->lock, flags);
344
345 if (copy_to_user(buf, &event, event.header.size))
346 return -EFAULT;
347 return event.header.size;
348
349 out:
350 finish_wait(&ctx->wq, &wait);
351 spin_unlock_irqrestore(&ctx->lock, flags);
352 return rc;
353 }
354
355 static const struct file_operations afu_fops = {
356 .owner = THIS_MODULE,
357 .open = afu_open,
358 .poll = afu_poll,
359 .read = afu_read,
360 .release = afu_release,
361 .unlocked_ioctl = afu_ioctl,
362 .compat_ioctl = afu_compat_ioctl,
363 .mmap = afu_mmap,
364 };
365
366 static const struct file_operations afu_master_fops = {
367 .owner = THIS_MODULE,
368 .open = afu_master_open,
369 .poll = afu_poll,
370 .read = afu_read,
371 .release = afu_release,
372 .unlocked_ioctl = afu_ioctl,
373 .compat_ioctl = afu_compat_ioctl,
374 .mmap = afu_mmap,
375 };
376
377
cxl_devnode(struct device * dev,umode_t * mode)378 static char *cxl_devnode(struct device *dev, umode_t *mode)
379 {
380 if (CXL_DEVT_IS_CARD(dev->devt)) {
381 /*
382 * These minor numbers will eventually be used to program the
383 * PSL and AFUs once we have dynamic reprogramming support
384 */
385 return NULL;
386 }
387 return kasprintf(GFP_KERNEL, "cxl/%s", dev_name(dev));
388 }
389
390 extern struct class *cxl_class;
391
cxl_add_chardev(struct cxl_afu * afu,dev_t devt,struct cdev * cdev,struct device ** chardev,char * postfix,char * desc,const struct file_operations * fops)392 static int cxl_add_chardev(struct cxl_afu *afu, dev_t devt, struct cdev *cdev,
393 struct device **chardev, char *postfix, char *desc,
394 const struct file_operations *fops)
395 {
396 struct device *dev;
397 int rc;
398
399 cdev_init(cdev, fops);
400 if ((rc = cdev_add(cdev, devt, 1))) {
401 dev_err(&afu->dev, "Unable to add %s chardev: %i\n", desc, rc);
402 return rc;
403 }
404
405 dev = device_create(cxl_class, &afu->dev, devt, afu,
406 "afu%i.%i%s", afu->adapter->adapter_num, afu->slice, postfix);
407 if (IS_ERR(dev)) {
408 dev_err(&afu->dev, "Unable to create %s chardev in sysfs: %i\n", desc, rc);
409 rc = PTR_ERR(dev);
410 goto err;
411 }
412
413 *chardev = dev;
414
415 return 0;
416 err:
417 cdev_del(cdev);
418 return rc;
419 }
420
cxl_chardev_d_afu_add(struct cxl_afu * afu)421 int cxl_chardev_d_afu_add(struct cxl_afu *afu)
422 {
423 return cxl_add_chardev(afu, CXL_AFU_MKDEV_D(afu), &afu->afu_cdev_d,
424 &afu->chardev_d, "d", "dedicated",
425 &afu_master_fops); /* Uses master fops */
426 }
427
cxl_chardev_m_afu_add(struct cxl_afu * afu)428 int cxl_chardev_m_afu_add(struct cxl_afu *afu)
429 {
430 return cxl_add_chardev(afu, CXL_AFU_MKDEV_M(afu), &afu->afu_cdev_m,
431 &afu->chardev_m, "m", "master",
432 &afu_master_fops);
433 }
434
cxl_chardev_s_afu_add(struct cxl_afu * afu)435 int cxl_chardev_s_afu_add(struct cxl_afu *afu)
436 {
437 return cxl_add_chardev(afu, CXL_AFU_MKDEV_S(afu), &afu->afu_cdev_s,
438 &afu->chardev_s, "s", "shared",
439 &afu_fops);
440 }
441
cxl_chardev_afu_remove(struct cxl_afu * afu)442 void cxl_chardev_afu_remove(struct cxl_afu *afu)
443 {
444 if (afu->chardev_d) {
445 cdev_del(&afu->afu_cdev_d);
446 device_unregister(afu->chardev_d);
447 afu->chardev_d = NULL;
448 }
449 if (afu->chardev_m) {
450 cdev_del(&afu->afu_cdev_m);
451 device_unregister(afu->chardev_m);
452 afu->chardev_m = NULL;
453 }
454 if (afu->chardev_s) {
455 cdev_del(&afu->afu_cdev_s);
456 device_unregister(afu->chardev_s);
457 afu->chardev_s = NULL;
458 }
459 }
460
cxl_register_afu(struct cxl_afu * afu)461 int cxl_register_afu(struct cxl_afu *afu)
462 {
463 afu->dev.class = cxl_class;
464
465 return device_register(&afu->dev);
466 }
467
cxl_register_adapter(struct cxl * adapter)468 int cxl_register_adapter(struct cxl *adapter)
469 {
470 adapter->dev.class = cxl_class;
471
472 /*
473 * Future: When we support dynamically reprogramming the PSL & AFU we
474 * will expose the interface to do that via a chardev:
475 * adapter->dev.devt = CXL_CARD_MKDEV(adapter);
476 */
477
478 return device_register(&adapter->dev);
479 }
480
cxl_file_init(void)481 int __init cxl_file_init(void)
482 {
483 int rc;
484
485 /*
486 * If these change we really need to update API. Either change some
487 * flags or update API version number CXL_API_VERSION.
488 */
489 BUILD_BUG_ON(CXL_API_VERSION != 1);
490 BUILD_BUG_ON(sizeof(struct cxl_ioctl_start_work) != 64);
491 BUILD_BUG_ON(sizeof(struct cxl_event_header) != 8);
492 BUILD_BUG_ON(sizeof(struct cxl_event_afu_interrupt) != 8);
493 BUILD_BUG_ON(sizeof(struct cxl_event_data_storage) != 32);
494 BUILD_BUG_ON(sizeof(struct cxl_event_afu_error) != 16);
495
496 if ((rc = alloc_chrdev_region(&cxl_dev, 0, CXL_NUM_MINORS, "cxl"))) {
497 pr_err("Unable to allocate CXL major number: %i\n", rc);
498 return rc;
499 }
500
501 pr_devel("CXL device allocated, MAJOR %i\n", MAJOR(cxl_dev));
502
503 cxl_class = class_create(THIS_MODULE, "cxl");
504 if (IS_ERR(cxl_class)) {
505 pr_err("Unable to create CXL class\n");
506 rc = PTR_ERR(cxl_class);
507 goto err;
508 }
509 cxl_class->devnode = cxl_devnode;
510
511 return 0;
512
513 err:
514 unregister_chrdev_region(cxl_dev, CXL_NUM_MINORS);
515 return rc;
516 }
517
cxl_file_exit(void)518 void cxl_file_exit(void)
519 {
520 unregister_chrdev_region(cxl_dev, CXL_NUM_MINORS);
521 class_destroy(cxl_class);
522 }
523