1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * IBM PowerPC Virtual I/O Infrastructure Support.
4  *
5  *    Copyright (c) 2003,2008 IBM Corp.
6  *     Dave Engebretsen engebret@us.ibm.com
7  *     Santiago Leon santil@us.ibm.com
8  *     Hollis Blanchard <hollisb@us.ibm.com>
9  *     Stephen Rothwell
10  *     Robert Jennings <rcjenn@us.ibm.com>
11  */
12 
13 #include <linux/cpu.h>
14 #include <linux/types.h>
15 #include <linux/delay.h>
16 #include <linux/stat.h>
17 #include <linux/device.h>
18 #include <linux/init.h>
19 #include <linux/slab.h>
20 #include <linux/console.h>
21 #include <linux/export.h>
22 #include <linux/mm.h>
23 #include <linux/dma-map-ops.h>
24 #include <linux/kobject.h>
25 #include <linux/kexec.h>
26 
27 #include <asm/iommu.h>
28 #include <asm/dma.h>
29 #include <asm/vio.h>
30 #include <asm/prom.h>
31 #include <asm/firmware.h>
32 #include <asm/tce.h>
33 #include <asm/page.h>
34 #include <asm/hvcall.h>
35 #include <asm/machdep.h>
36 
37 static struct vio_dev vio_bus_device  = { /* fake "parent" device */
38 	.name = "vio",
39 	.type = "",
40 	.dev.init_name = "vio",
41 	.dev.bus = &vio_bus_type,
42 };
43 
44 #ifdef CONFIG_PPC_SMLPAR
45 /**
46  * vio_cmo_pool - A pool of IO memory for CMO use
47  *
48  * @size: The size of the pool in bytes
49  * @free: The amount of free memory in the pool
50  */
51 struct vio_cmo_pool {
52 	size_t size;
53 	size_t free;
54 };
55 
56 /* How many ms to delay queued balance work */
57 #define VIO_CMO_BALANCE_DELAY 100
58 
59 /* Portion out IO memory to CMO devices by this chunk size */
60 #define VIO_CMO_BALANCE_CHUNK 131072
61 
62 /**
63  * vio_cmo_dev_entry - A device that is CMO-enabled and requires entitlement
64  *
65  * @vio_dev: struct vio_dev pointer
66  * @list: pointer to other devices on bus that are being tracked
67  */
68 struct vio_cmo_dev_entry {
69 	struct vio_dev *viodev;
70 	struct list_head list;
71 };
72 
73 /**
74  * vio_cmo - VIO bus accounting structure for CMO entitlement
75  *
76  * @lock: spinlock for entire structure
77  * @balance_q: work queue for balancing system entitlement
78  * @device_list: list of CMO-enabled devices requiring entitlement
79  * @entitled: total system entitlement in bytes
80  * @reserve: pool of memory from which devices reserve entitlement, incl. spare
81  * @excess: pool of excess entitlement not needed for device reserves or spare
82  * @spare: IO memory for device hotplug functionality
83  * @min: minimum necessary for system operation
84  * @desired: desired memory for system operation
85  * @curr: bytes currently allocated
86  * @high: high water mark for IO data usage
87  */
88 static struct vio_cmo {
89 	spinlock_t lock;
90 	struct delayed_work balance_q;
91 	struct list_head device_list;
92 	size_t entitled;
93 	struct vio_cmo_pool reserve;
94 	struct vio_cmo_pool excess;
95 	size_t spare;
96 	size_t min;
97 	size_t desired;
98 	size_t curr;
99 	size_t high;
100 } vio_cmo;
101 
102 /**
103  * vio_cmo_OF_devices - Count the number of OF devices that have DMA windows
104  */
105 static int vio_cmo_num_OF_devs(void)
106 {
107 	struct device_node *node_vroot;
108 	int count = 0;
109 
110 	/*
111 	 * Count the number of vdevice entries with an
112 	 * ibm,my-dma-window OF property
113 	 */
114 	node_vroot = of_find_node_by_name(NULL, "vdevice");
115 	if (node_vroot) {
116 		struct device_node *of_node;
117 		struct property *prop;
118 
119 		for_each_child_of_node(node_vroot, of_node) {
120 			prop = of_find_property(of_node, "ibm,my-dma-window",
121 			                       NULL);
122 			if (prop)
123 				count++;
124 		}
125 	}
126 	of_node_put(node_vroot);
127 	return count;
128 }
129 
130 /**
131  * vio_cmo_alloc - allocate IO memory for CMO-enable devices
132  *
133  * @viodev: VIO device requesting IO memory
134  * @size: size of allocation requested
135  *
136  * Allocations come from memory reserved for the devices and any excess
137  * IO memory available to all devices.  The spare pool used to service
138  * hotplug must be equal to %VIO_CMO_MIN_ENT for the excess pool to be
139  * made available.
140  *
141  * Return codes:
142  *  0 for successful allocation and -ENOMEM for a failure
143  */
144 static inline int vio_cmo_alloc(struct vio_dev *viodev, size_t size)
145 {
146 	unsigned long flags;
147 	size_t reserve_free = 0;
148 	size_t excess_free = 0;
149 	int ret = -ENOMEM;
150 
151 	spin_lock_irqsave(&vio_cmo.lock, flags);
152 
153 	/* Determine the amount of free entitlement available in reserve */
154 	if (viodev->cmo.entitled > viodev->cmo.allocated)
155 		reserve_free = viodev->cmo.entitled - viodev->cmo.allocated;
156 
157 	/* If spare is not fulfilled, the excess pool can not be used. */
158 	if (vio_cmo.spare >= VIO_CMO_MIN_ENT)
159 		excess_free = vio_cmo.excess.free;
160 
161 	/* The request can be satisfied */
162 	if ((reserve_free + excess_free) >= size) {
163 		vio_cmo.curr += size;
164 		if (vio_cmo.curr > vio_cmo.high)
165 			vio_cmo.high = vio_cmo.curr;
166 		viodev->cmo.allocated += size;
167 		size -= min(reserve_free, size);
168 		vio_cmo.excess.free -= size;
169 		ret = 0;
170 	}
171 
172 	spin_unlock_irqrestore(&vio_cmo.lock, flags);
173 	return ret;
174 }
175 
176 /**
177  * vio_cmo_dealloc - deallocate IO memory from CMO-enable devices
178  * @viodev: VIO device freeing IO memory
179  * @size: size of deallocation
180  *
181  * IO memory is freed by the device back to the correct memory pools.
182  * The spare pool is replenished first from either memory pool, then
183  * the reserve pool is used to reduce device entitlement, the excess
184  * pool is used to increase the reserve pool toward the desired entitlement
185  * target, and then the remaining memory is returned to the pools.
186  *
187  */
188 static inline void vio_cmo_dealloc(struct vio_dev *viodev, size_t size)
189 {
190 	unsigned long flags;
191 	size_t spare_needed = 0;
192 	size_t excess_freed = 0;
193 	size_t reserve_freed = size;
194 	size_t tmp;
195 	int balance = 0;
196 
197 	spin_lock_irqsave(&vio_cmo.lock, flags);
198 	vio_cmo.curr -= size;
199 
200 	/* Amount of memory freed from the excess pool */
201 	if (viodev->cmo.allocated > viodev->cmo.entitled) {
202 		excess_freed = min(reserve_freed, (viodev->cmo.allocated -
203 		                                   viodev->cmo.entitled));
204 		reserve_freed -= excess_freed;
205 	}
206 
207 	/* Remove allocation from device */
208 	viodev->cmo.allocated -= (reserve_freed + excess_freed);
209 
210 	/* Spare is a subset of the reserve pool, replenish it first. */
211 	spare_needed = VIO_CMO_MIN_ENT - vio_cmo.spare;
212 
213 	/*
214 	 * Replenish the spare in the reserve pool from the excess pool.
215 	 * This moves entitlement into the reserve pool.
216 	 */
217 	if (spare_needed && excess_freed) {
218 		tmp = min(excess_freed, spare_needed);
219 		vio_cmo.excess.size -= tmp;
220 		vio_cmo.reserve.size += tmp;
221 		vio_cmo.spare += tmp;
222 		excess_freed -= tmp;
223 		spare_needed -= tmp;
224 		balance = 1;
225 	}
226 
227 	/*
228 	 * Replenish the spare in the reserve pool from the reserve pool.
229 	 * This removes entitlement from the device down to VIO_CMO_MIN_ENT,
230 	 * if needed, and gives it to the spare pool. The amount of used
231 	 * memory in this pool does not change.
232 	 */
233 	if (spare_needed && reserve_freed) {
234 		tmp = min3(spare_needed, reserve_freed, (viodev->cmo.entitled - VIO_CMO_MIN_ENT));
235 
236 		vio_cmo.spare += tmp;
237 		viodev->cmo.entitled -= tmp;
238 		reserve_freed -= tmp;
239 		spare_needed -= tmp;
240 		balance = 1;
241 	}
242 
243 	/*
244 	 * Increase the reserve pool until the desired allocation is met.
245 	 * Move an allocation freed from the excess pool into the reserve
246 	 * pool and schedule a balance operation.
247 	 */
248 	if (excess_freed && (vio_cmo.desired > vio_cmo.reserve.size)) {
249 		tmp = min(excess_freed, (vio_cmo.desired - vio_cmo.reserve.size));
250 
251 		vio_cmo.excess.size -= tmp;
252 		vio_cmo.reserve.size += tmp;
253 		excess_freed -= tmp;
254 		balance = 1;
255 	}
256 
257 	/* Return memory from the excess pool to that pool */
258 	if (excess_freed)
259 		vio_cmo.excess.free += excess_freed;
260 
261 	if (balance)
262 		schedule_delayed_work(&vio_cmo.balance_q, VIO_CMO_BALANCE_DELAY);
263 	spin_unlock_irqrestore(&vio_cmo.lock, flags);
264 }
265 
266 /**
267  * vio_cmo_entitlement_update - Manage system entitlement changes
268  *
269  * @new_entitlement: new system entitlement to attempt to accommodate
270  *
271  * Increases in entitlement will be used to fulfill the spare entitlement
272  * and the rest is given to the excess pool.  Decreases, if they are
273  * possible, come from the excess pool and from unused device entitlement
274  *
275  * Returns: 0 on success, -ENOMEM when change can not be made
276  */
277 int vio_cmo_entitlement_update(size_t new_entitlement)
278 {
279 	struct vio_dev *viodev;
280 	struct vio_cmo_dev_entry *dev_ent;
281 	unsigned long flags;
282 	size_t avail, delta, tmp;
283 
284 	spin_lock_irqsave(&vio_cmo.lock, flags);
285 
286 	/* Entitlement increases */
287 	if (new_entitlement > vio_cmo.entitled) {
288 		delta = new_entitlement - vio_cmo.entitled;
289 
290 		/* Fulfill spare allocation */
291 		if (vio_cmo.spare < VIO_CMO_MIN_ENT) {
292 			tmp = min(delta, (VIO_CMO_MIN_ENT - vio_cmo.spare));
293 			vio_cmo.spare += tmp;
294 			vio_cmo.reserve.size += tmp;
295 			delta -= tmp;
296 		}
297 
298 		/* Remaining new allocation goes to the excess pool */
299 		vio_cmo.entitled += delta;
300 		vio_cmo.excess.size += delta;
301 		vio_cmo.excess.free += delta;
302 
303 		goto out;
304 	}
305 
306 	/* Entitlement decreases */
307 	delta = vio_cmo.entitled - new_entitlement;
308 	avail = vio_cmo.excess.free;
309 
310 	/*
311 	 * Need to check how much unused entitlement each device can
312 	 * sacrifice to fulfill entitlement change.
313 	 */
314 	list_for_each_entry(dev_ent, &vio_cmo.device_list, list) {
315 		if (avail >= delta)
316 			break;
317 
318 		viodev = dev_ent->viodev;
319 		if ((viodev->cmo.entitled > viodev->cmo.allocated) &&
320 		    (viodev->cmo.entitled > VIO_CMO_MIN_ENT))
321 				avail += viodev->cmo.entitled -
322 				         max_t(size_t, viodev->cmo.allocated,
323 				               VIO_CMO_MIN_ENT);
324 	}
325 
326 	if (delta <= avail) {
327 		vio_cmo.entitled -= delta;
328 
329 		/* Take entitlement from the excess pool first */
330 		tmp = min(vio_cmo.excess.free, delta);
331 		vio_cmo.excess.size -= tmp;
332 		vio_cmo.excess.free -= tmp;
333 		delta -= tmp;
334 
335 		/*
336 		 * Remove all but VIO_CMO_MIN_ENT bytes from devices
337 		 * until entitlement change is served
338 		 */
339 		list_for_each_entry(dev_ent, &vio_cmo.device_list, list) {
340 			if (!delta)
341 				break;
342 
343 			viodev = dev_ent->viodev;
344 			tmp = 0;
345 			if ((viodev->cmo.entitled > viodev->cmo.allocated) &&
346 			    (viodev->cmo.entitled > VIO_CMO_MIN_ENT))
347 				tmp = viodev->cmo.entitled -
348 				      max_t(size_t, viodev->cmo.allocated,
349 				            VIO_CMO_MIN_ENT);
350 			viodev->cmo.entitled -= min(tmp, delta);
351 			delta -= min(tmp, delta);
352 		}
353 	} else {
354 		spin_unlock_irqrestore(&vio_cmo.lock, flags);
355 		return -ENOMEM;
356 	}
357 
358 out:
359 	schedule_delayed_work(&vio_cmo.balance_q, 0);
360 	spin_unlock_irqrestore(&vio_cmo.lock, flags);
361 	return 0;
362 }
363 
364 /**
365  * vio_cmo_balance - Balance entitlement among devices
366  *
367  * @work: work queue structure for this operation
368  *
369  * Any system entitlement above the minimum needed for devices, or
370  * already allocated to devices, can be distributed to the devices.
371  * The list of devices is iterated through to recalculate the desired
372  * entitlement level and to determine how much entitlement above the
373  * minimum entitlement is allocated to devices.
374  *
375  * Small chunks of the available entitlement are given to devices until
376  * their requirements are fulfilled or there is no entitlement left to give.
377  * Upon completion sizes of the reserve and excess pools are calculated.
378  *
379  * The system minimum entitlement level is also recalculated here.
380  * Entitlement will be reserved for devices even after vio_bus_remove to
381  * accommodate reloading the driver.  The OF tree is walked to count the
382  * number of devices present and this will remove entitlement for devices
383  * that have actually left the system after having vio_bus_remove called.
384  */
385 static void vio_cmo_balance(struct work_struct *work)
386 {
387 	struct vio_cmo *cmo;
388 	struct vio_dev *viodev;
389 	struct vio_cmo_dev_entry *dev_ent;
390 	unsigned long flags;
391 	size_t avail = 0, level, chunk, need;
392 	int devcount = 0, fulfilled;
393 
394 	cmo = container_of(work, struct vio_cmo, balance_q.work);
395 
396 	spin_lock_irqsave(&vio_cmo.lock, flags);
397 
398 	/* Calculate minimum entitlement and fulfill spare */
399 	cmo->min = vio_cmo_num_OF_devs() * VIO_CMO_MIN_ENT;
400 	BUG_ON(cmo->min > cmo->entitled);
401 	cmo->spare = min_t(size_t, VIO_CMO_MIN_ENT, (cmo->entitled - cmo->min));
402 	cmo->min += cmo->spare;
403 	cmo->desired = cmo->min;
404 
405 	/*
406 	 * Determine how much entitlement is available and reset device
407 	 * entitlements
408 	 */
409 	avail = cmo->entitled - cmo->spare;
410 	list_for_each_entry(dev_ent, &vio_cmo.device_list, list) {
411 		viodev = dev_ent->viodev;
412 		devcount++;
413 		viodev->cmo.entitled = VIO_CMO_MIN_ENT;
414 		cmo->desired += (viodev->cmo.desired - VIO_CMO_MIN_ENT);
415 		avail -= max_t(size_t, viodev->cmo.allocated, VIO_CMO_MIN_ENT);
416 	}
417 
418 	/*
419 	 * Having provided each device with the minimum entitlement, loop
420 	 * over the devices portioning out the remaining entitlement
421 	 * until there is nothing left.
422 	 */
423 	level = VIO_CMO_MIN_ENT;
424 	while (avail) {
425 		fulfilled = 0;
426 		list_for_each_entry(dev_ent, &vio_cmo.device_list, list) {
427 			viodev = dev_ent->viodev;
428 
429 			if (viodev->cmo.desired <= level) {
430 				fulfilled++;
431 				continue;
432 			}
433 
434 			/*
435 			 * Give the device up to VIO_CMO_BALANCE_CHUNK
436 			 * bytes of entitlement, but do not exceed the
437 			 * desired level of entitlement for the device.
438 			 */
439 			chunk = min_t(size_t, avail, VIO_CMO_BALANCE_CHUNK);
440 			chunk = min(chunk, (viodev->cmo.desired -
441 			                    viodev->cmo.entitled));
442 			viodev->cmo.entitled += chunk;
443 
444 			/*
445 			 * If the memory for this entitlement increase was
446 			 * already allocated to the device it does not come
447 			 * from the available pool being portioned out.
448 			 */
449 			need = max(viodev->cmo.allocated, viodev->cmo.entitled)-
450 			       max(viodev->cmo.allocated, level);
451 			avail -= need;
452 
453 		}
454 		if (fulfilled == devcount)
455 			break;
456 		level += VIO_CMO_BALANCE_CHUNK;
457 	}
458 
459 	/* Calculate new reserve and excess pool sizes */
460 	cmo->reserve.size = cmo->min;
461 	cmo->excess.free = 0;
462 	cmo->excess.size = 0;
463 	need = 0;
464 	list_for_each_entry(dev_ent, &vio_cmo.device_list, list) {
465 		viodev = dev_ent->viodev;
466 		/* Calculated reserve size above the minimum entitlement */
467 		if (viodev->cmo.entitled)
468 			cmo->reserve.size += (viodev->cmo.entitled -
469 			                      VIO_CMO_MIN_ENT);
470 		/* Calculated used excess entitlement */
471 		if (viodev->cmo.allocated > viodev->cmo.entitled)
472 			need += viodev->cmo.allocated - viodev->cmo.entitled;
473 	}
474 	cmo->excess.size = cmo->entitled - cmo->reserve.size;
475 	cmo->excess.free = cmo->excess.size - need;
476 
477 	cancel_delayed_work(to_delayed_work(work));
478 	spin_unlock_irqrestore(&vio_cmo.lock, flags);
479 }
480 
481 static void *vio_dma_iommu_alloc_coherent(struct device *dev, size_t size,
482 					  dma_addr_t *dma_handle, gfp_t flag,
483 					  unsigned long attrs)
484 {
485 	struct vio_dev *viodev = to_vio_dev(dev);
486 	void *ret;
487 
488 	if (vio_cmo_alloc(viodev, roundup(size, PAGE_SIZE))) {
489 		atomic_inc(&viodev->cmo.allocs_failed);
490 		return NULL;
491 	}
492 
493 	ret = iommu_alloc_coherent(dev, get_iommu_table_base(dev), size,
494 				    dma_handle, dev->coherent_dma_mask, flag,
495 				    dev_to_node(dev));
496 	if (unlikely(ret == NULL)) {
497 		vio_cmo_dealloc(viodev, roundup(size, PAGE_SIZE));
498 		atomic_inc(&viodev->cmo.allocs_failed);
499 	}
500 
501 	return ret;
502 }
503 
504 static void vio_dma_iommu_free_coherent(struct device *dev, size_t size,
505 					void *vaddr, dma_addr_t dma_handle,
506 					unsigned long attrs)
507 {
508 	struct vio_dev *viodev = to_vio_dev(dev);
509 
510 	iommu_free_coherent(get_iommu_table_base(dev), size, vaddr, dma_handle);
511 	vio_cmo_dealloc(viodev, roundup(size, PAGE_SIZE));
512 }
513 
514 static dma_addr_t vio_dma_iommu_map_page(struct device *dev, struct page *page,
515                                          unsigned long offset, size_t size,
516                                          enum dma_data_direction direction,
517                                          unsigned long attrs)
518 {
519 	struct vio_dev *viodev = to_vio_dev(dev);
520 	struct iommu_table *tbl = get_iommu_table_base(dev);
521 	dma_addr_t ret = DMA_MAPPING_ERROR;
522 
523 	if (vio_cmo_alloc(viodev, roundup(size, IOMMU_PAGE_SIZE(tbl))))
524 		goto out_fail;
525 	ret = iommu_map_page(dev, tbl, page, offset, size, dma_get_mask(dev),
526 			direction, attrs);
527 	if (unlikely(ret == DMA_MAPPING_ERROR))
528 		goto out_deallocate;
529 	return ret;
530 
531 out_deallocate:
532 	vio_cmo_dealloc(viodev, roundup(size, IOMMU_PAGE_SIZE(tbl)));
533 out_fail:
534 	atomic_inc(&viodev->cmo.allocs_failed);
535 	return DMA_MAPPING_ERROR;
536 }
537 
538 static void vio_dma_iommu_unmap_page(struct device *dev, dma_addr_t dma_handle,
539 				     size_t size,
540 				     enum dma_data_direction direction,
541 				     unsigned long attrs)
542 {
543 	struct vio_dev *viodev = to_vio_dev(dev);
544 	struct iommu_table *tbl = get_iommu_table_base(dev);
545 
546 	iommu_unmap_page(tbl, dma_handle, size, direction, attrs);
547 	vio_cmo_dealloc(viodev, roundup(size, IOMMU_PAGE_SIZE(tbl)));
548 }
549 
550 static int vio_dma_iommu_map_sg(struct device *dev, struct scatterlist *sglist,
551                                 int nelems, enum dma_data_direction direction,
552                                 unsigned long attrs)
553 {
554 	struct vio_dev *viodev = to_vio_dev(dev);
555 	struct iommu_table *tbl = get_iommu_table_base(dev);
556 	struct scatterlist *sgl;
557 	int ret, count;
558 	size_t alloc_size = 0;
559 
560 	for_each_sg(sglist, sgl, nelems, count)
561 		alloc_size += roundup(sgl->length, IOMMU_PAGE_SIZE(tbl));
562 
563 	ret = vio_cmo_alloc(viodev, alloc_size);
564 	if (ret)
565 		goto out_fail;
566 	ret = ppc_iommu_map_sg(dev, tbl, sglist, nelems, dma_get_mask(dev),
567 			direction, attrs);
568 	if (unlikely(!ret))
569 		goto out_deallocate;
570 
571 	for_each_sg(sglist, sgl, ret, count)
572 		alloc_size -= roundup(sgl->dma_length, IOMMU_PAGE_SIZE(tbl));
573 	if (alloc_size)
574 		vio_cmo_dealloc(viodev, alloc_size);
575 	return ret;
576 
577 out_deallocate:
578 	vio_cmo_dealloc(viodev, alloc_size);
579 out_fail:
580 	atomic_inc(&viodev->cmo.allocs_failed);
581 	return ret;
582 }
583 
584 static void vio_dma_iommu_unmap_sg(struct device *dev,
585 		struct scatterlist *sglist, int nelems,
586 		enum dma_data_direction direction,
587 		unsigned long attrs)
588 {
589 	struct vio_dev *viodev = to_vio_dev(dev);
590 	struct iommu_table *tbl = get_iommu_table_base(dev);
591 	struct scatterlist *sgl;
592 	size_t alloc_size = 0;
593 	int count;
594 
595 	for_each_sg(sglist, sgl, nelems, count)
596 		alloc_size += roundup(sgl->dma_length, IOMMU_PAGE_SIZE(tbl));
597 
598 	ppc_iommu_unmap_sg(tbl, sglist, nelems, direction, attrs);
599 	vio_cmo_dealloc(viodev, alloc_size);
600 }
601 
602 static const struct dma_map_ops vio_dma_mapping_ops = {
603 	.alloc             = vio_dma_iommu_alloc_coherent,
604 	.free              = vio_dma_iommu_free_coherent,
605 	.map_sg            = vio_dma_iommu_map_sg,
606 	.unmap_sg          = vio_dma_iommu_unmap_sg,
607 	.map_page          = vio_dma_iommu_map_page,
608 	.unmap_page        = vio_dma_iommu_unmap_page,
609 	.dma_supported     = dma_iommu_dma_supported,
610 	.get_required_mask = dma_iommu_get_required_mask,
611 	.mmap		   = dma_common_mmap,
612 	.get_sgtable	   = dma_common_get_sgtable,
613 	.alloc_pages	   = dma_common_alloc_pages,
614 	.free_pages	   = dma_common_free_pages,
615 };
616 
617 /**
618  * vio_cmo_set_dev_desired - Set desired entitlement for a device
619  *
620  * @viodev: struct vio_dev for device to alter
621  * @desired: new desired entitlement level in bytes
622  *
623  * For use by devices to request a change to their entitlement at runtime or
624  * through sysfs.  The desired entitlement level is changed and a balancing
625  * of system resources is scheduled to run in the future.
626  */
627 void vio_cmo_set_dev_desired(struct vio_dev *viodev, size_t desired)
628 {
629 	unsigned long flags;
630 	struct vio_cmo_dev_entry *dev_ent;
631 	int found = 0;
632 
633 	if (!firmware_has_feature(FW_FEATURE_CMO))
634 		return;
635 
636 	spin_lock_irqsave(&vio_cmo.lock, flags);
637 	if (desired < VIO_CMO_MIN_ENT)
638 		desired = VIO_CMO_MIN_ENT;
639 
640 	/*
641 	 * Changes will not be made for devices not in the device list.
642 	 * If it is not in the device list, then no driver is loaded
643 	 * for the device and it can not receive entitlement.
644 	 */
645 	list_for_each_entry(dev_ent, &vio_cmo.device_list, list)
646 		if (viodev == dev_ent->viodev) {
647 			found = 1;
648 			break;
649 		}
650 	if (!found) {
651 		spin_unlock_irqrestore(&vio_cmo.lock, flags);
652 		return;
653 	}
654 
655 	/* Increase/decrease in desired device entitlement */
656 	if (desired >= viodev->cmo.desired) {
657 		/* Just bump the bus and device values prior to a balance*/
658 		vio_cmo.desired += desired - viodev->cmo.desired;
659 		viodev->cmo.desired = desired;
660 	} else {
661 		/* Decrease bus and device values for desired entitlement */
662 		vio_cmo.desired -= viodev->cmo.desired - desired;
663 		viodev->cmo.desired = desired;
664 		/*
665 		 * If less entitlement is desired than current entitlement, move
666 		 * any reserve memory in the change region to the excess pool.
667 		 */
668 		if (viodev->cmo.entitled > desired) {
669 			vio_cmo.reserve.size -= viodev->cmo.entitled - desired;
670 			vio_cmo.excess.size += viodev->cmo.entitled - desired;
671 			/*
672 			 * If entitlement moving from the reserve pool to the
673 			 * excess pool is currently unused, add to the excess
674 			 * free counter.
675 			 */
676 			if (viodev->cmo.allocated < viodev->cmo.entitled)
677 				vio_cmo.excess.free += viodev->cmo.entitled -
678 				                       max(viodev->cmo.allocated, desired);
679 			viodev->cmo.entitled = desired;
680 		}
681 	}
682 	schedule_delayed_work(&vio_cmo.balance_q, 0);
683 	spin_unlock_irqrestore(&vio_cmo.lock, flags);
684 }
685 
686 /**
687  * vio_cmo_bus_probe - Handle CMO specific bus probe activities
688  *
689  * @viodev - Pointer to struct vio_dev for device
690  *
691  * Determine the devices IO memory entitlement needs, attempting
692  * to satisfy the system minimum entitlement at first and scheduling
693  * a balance operation to take care of the rest at a later time.
694  *
695  * Returns: 0 on success, -EINVAL when device doesn't support CMO, and
696  *          -ENOMEM when entitlement is not available for device or
697  *          device entry.
698  *
699  */
700 static int vio_cmo_bus_probe(struct vio_dev *viodev)
701 {
702 	struct vio_cmo_dev_entry *dev_ent;
703 	struct device *dev = &viodev->dev;
704 	struct iommu_table *tbl;
705 	struct vio_driver *viodrv = to_vio_driver(dev->driver);
706 	unsigned long flags;
707 	size_t size;
708 	bool dma_capable = false;
709 
710 	tbl = get_iommu_table_base(dev);
711 
712 	/* A device requires entitlement if it has a DMA window property */
713 	switch (viodev->family) {
714 	case VDEVICE:
715 		if (of_get_property(viodev->dev.of_node,
716 					"ibm,my-dma-window", NULL))
717 			dma_capable = true;
718 		break;
719 	case PFO:
720 		dma_capable = false;
721 		break;
722 	default:
723 		dev_warn(dev, "unknown device family: %d\n", viodev->family);
724 		BUG();
725 		break;
726 	}
727 
728 	/* Configure entitlement for the device. */
729 	if (dma_capable) {
730 		/* Check that the driver is CMO enabled and get desired DMA */
731 		if (!viodrv->get_desired_dma) {
732 			dev_err(dev, "%s: device driver does not support CMO\n",
733 			        __func__);
734 			return -EINVAL;
735 		}
736 
737 		viodev->cmo.desired =
738 			IOMMU_PAGE_ALIGN(viodrv->get_desired_dma(viodev), tbl);
739 		if (viodev->cmo.desired < VIO_CMO_MIN_ENT)
740 			viodev->cmo.desired = VIO_CMO_MIN_ENT;
741 		size = VIO_CMO_MIN_ENT;
742 
743 		dev_ent = kmalloc(sizeof(struct vio_cmo_dev_entry),
744 		                  GFP_KERNEL);
745 		if (!dev_ent)
746 			return -ENOMEM;
747 
748 		dev_ent->viodev = viodev;
749 		spin_lock_irqsave(&vio_cmo.lock, flags);
750 		list_add(&dev_ent->list, &vio_cmo.device_list);
751 	} else {
752 		viodev->cmo.desired = 0;
753 		size = 0;
754 		spin_lock_irqsave(&vio_cmo.lock, flags);
755 	}
756 
757 	/*
758 	 * If the needs for vio_cmo.min have not changed since they
759 	 * were last set, the number of devices in the OF tree has
760 	 * been constant and the IO memory for this is already in
761 	 * the reserve pool.
762 	 */
763 	if (vio_cmo.min == ((vio_cmo_num_OF_devs() + 1) *
764 	                    VIO_CMO_MIN_ENT)) {
765 		/* Updated desired entitlement if device requires it */
766 		if (size)
767 			vio_cmo.desired += (viodev->cmo.desired -
768 		                        VIO_CMO_MIN_ENT);
769 	} else {
770 		size_t tmp;
771 
772 		tmp = vio_cmo.spare + vio_cmo.excess.free;
773 		if (tmp < size) {
774 			dev_err(dev, "%s: insufficient free "
775 			        "entitlement to add device. "
776 			        "Need %lu, have %lu\n", __func__,
777 				size, (vio_cmo.spare + tmp));
778 			spin_unlock_irqrestore(&vio_cmo.lock, flags);
779 			return -ENOMEM;
780 		}
781 
782 		/* Use excess pool first to fulfill request */
783 		tmp = min(size, vio_cmo.excess.free);
784 		vio_cmo.excess.free -= tmp;
785 		vio_cmo.excess.size -= tmp;
786 		vio_cmo.reserve.size += tmp;
787 
788 		/* Use spare if excess pool was insufficient */
789 		vio_cmo.spare -= size - tmp;
790 
791 		/* Update bus accounting */
792 		vio_cmo.min += size;
793 		vio_cmo.desired += viodev->cmo.desired;
794 	}
795 	spin_unlock_irqrestore(&vio_cmo.lock, flags);
796 	return 0;
797 }
798 
799 /**
800  * vio_cmo_bus_remove - Handle CMO specific bus removal activities
801  *
802  * @viodev - Pointer to struct vio_dev for device
803  *
804  * Remove the device from the cmo device list.  The minimum entitlement
805  * will be reserved for the device as long as it is in the system.  The
806  * rest of the entitlement the device had been allocated will be returned
807  * to the system.
808  */
809 static void vio_cmo_bus_remove(struct vio_dev *viodev)
810 {
811 	struct vio_cmo_dev_entry *dev_ent;
812 	unsigned long flags;
813 	size_t tmp;
814 
815 	spin_lock_irqsave(&vio_cmo.lock, flags);
816 	if (viodev->cmo.allocated) {
817 		dev_err(&viodev->dev, "%s: device had %lu bytes of IO "
818 		        "allocated after remove operation.\n",
819 		        __func__, viodev->cmo.allocated);
820 		BUG();
821 	}
822 
823 	/*
824 	 * Remove the device from the device list being maintained for
825 	 * CMO enabled devices.
826 	 */
827 	list_for_each_entry(dev_ent, &vio_cmo.device_list, list)
828 		if (viodev == dev_ent->viodev) {
829 			list_del(&dev_ent->list);
830 			kfree(dev_ent);
831 			break;
832 		}
833 
834 	/*
835 	 * Devices may not require any entitlement and they do not need
836 	 * to be processed.  Otherwise, return the device's entitlement
837 	 * back to the pools.
838 	 */
839 	if (viodev->cmo.entitled) {
840 		/*
841 		 * This device has not yet left the OF tree, it's
842 		 * minimum entitlement remains in vio_cmo.min and
843 		 * vio_cmo.desired
844 		 */
845 		vio_cmo.desired -= (viodev->cmo.desired - VIO_CMO_MIN_ENT);
846 
847 		/*
848 		 * Save min allocation for device in reserve as long
849 		 * as it exists in OF tree as determined by later
850 		 * balance operation
851 		 */
852 		viodev->cmo.entitled -= VIO_CMO_MIN_ENT;
853 
854 		/* Replenish spare from freed reserve pool */
855 		if (viodev->cmo.entitled && (vio_cmo.spare < VIO_CMO_MIN_ENT)) {
856 			tmp = min(viodev->cmo.entitled, (VIO_CMO_MIN_ENT -
857 			                                 vio_cmo.spare));
858 			vio_cmo.spare += tmp;
859 			viodev->cmo.entitled -= tmp;
860 		}
861 
862 		/* Remaining reserve goes to excess pool */
863 		vio_cmo.excess.size += viodev->cmo.entitled;
864 		vio_cmo.excess.free += viodev->cmo.entitled;
865 		vio_cmo.reserve.size -= viodev->cmo.entitled;
866 
867 		/*
868 		 * Until the device is removed it will keep a
869 		 * minimum entitlement; this will guarantee that
870 		 * a module unload/load will result in a success.
871 		 */
872 		viodev->cmo.entitled = VIO_CMO_MIN_ENT;
873 		viodev->cmo.desired = VIO_CMO_MIN_ENT;
874 		atomic_set(&viodev->cmo.allocs_failed, 0);
875 	}
876 
877 	spin_unlock_irqrestore(&vio_cmo.lock, flags);
878 }
879 
880 static void vio_cmo_set_dma_ops(struct vio_dev *viodev)
881 {
882 	set_dma_ops(&viodev->dev, &vio_dma_mapping_ops);
883 }
884 
885 /**
886  * vio_cmo_bus_init - CMO entitlement initialization at bus init time
887  *
888  * Set up the reserve and excess entitlement pools based on available
889  * system entitlement and the number of devices in the OF tree that
890  * require entitlement in the reserve pool.
891  */
892 static void vio_cmo_bus_init(void)
893 {
894 	struct hvcall_mpp_data mpp_data;
895 	int err;
896 
897 	memset(&vio_cmo, 0, sizeof(struct vio_cmo));
898 	spin_lock_init(&vio_cmo.lock);
899 	INIT_LIST_HEAD(&vio_cmo.device_list);
900 	INIT_DELAYED_WORK(&vio_cmo.balance_q, vio_cmo_balance);
901 
902 	/* Get current system entitlement */
903 	err = h_get_mpp(&mpp_data);
904 
905 	/*
906 	 * On failure, continue with entitlement set to 0, will panic()
907 	 * later when spare is reserved.
908 	 */
909 	if (err != H_SUCCESS) {
910 		printk(KERN_ERR "%s: unable to determine system IO "\
911 		       "entitlement. (%d)\n", __func__, err);
912 		vio_cmo.entitled = 0;
913 	} else {
914 		vio_cmo.entitled = mpp_data.entitled_mem;
915 	}
916 
917 	/* Set reservation and check against entitlement */
918 	vio_cmo.spare = VIO_CMO_MIN_ENT;
919 	vio_cmo.reserve.size = vio_cmo.spare;
920 	vio_cmo.reserve.size += (vio_cmo_num_OF_devs() *
921 	                         VIO_CMO_MIN_ENT);
922 	if (vio_cmo.reserve.size > vio_cmo.entitled) {
923 		printk(KERN_ERR "%s: insufficient system entitlement\n",
924 		       __func__);
925 		panic("%s: Insufficient system entitlement", __func__);
926 	}
927 
928 	/* Set the remaining accounting variables */
929 	vio_cmo.excess.size = vio_cmo.entitled - vio_cmo.reserve.size;
930 	vio_cmo.excess.free = vio_cmo.excess.size;
931 	vio_cmo.min = vio_cmo.reserve.size;
932 	vio_cmo.desired = vio_cmo.reserve.size;
933 }
934 
935 /* sysfs device functions and data structures for CMO */
936 
937 #define viodev_cmo_rd_attr(name)                                        \
938 static ssize_t cmo_##name##_show(struct device *dev,                    \
939                                         struct device_attribute *attr,  \
940                                          char *buf)                     \
941 {                                                                       \
942 	return sprintf(buf, "%lu\n", to_vio_dev(dev)->cmo.name);        \
943 }
944 
945 static ssize_t cmo_allocs_failed_show(struct device *dev,
946 		struct device_attribute *attr, char *buf)
947 {
948 	struct vio_dev *viodev = to_vio_dev(dev);
949 	return sprintf(buf, "%d\n", atomic_read(&viodev->cmo.allocs_failed));
950 }
951 
952 static ssize_t cmo_allocs_failed_store(struct device *dev,
953 		struct device_attribute *attr, const char *buf, size_t count)
954 {
955 	struct vio_dev *viodev = to_vio_dev(dev);
956 	atomic_set(&viodev->cmo.allocs_failed, 0);
957 	return count;
958 }
959 
960 static ssize_t cmo_desired_store(struct device *dev,
961 		struct device_attribute *attr, const char *buf, size_t count)
962 {
963 	struct vio_dev *viodev = to_vio_dev(dev);
964 	size_t new_desired;
965 	int ret;
966 
967 	ret = kstrtoul(buf, 10, &new_desired);
968 	if (ret)
969 		return ret;
970 
971 	vio_cmo_set_dev_desired(viodev, new_desired);
972 	return count;
973 }
974 
975 viodev_cmo_rd_attr(desired);
976 viodev_cmo_rd_attr(entitled);
977 viodev_cmo_rd_attr(allocated);
978 
979 static ssize_t name_show(struct device *, struct device_attribute *, char *);
980 static ssize_t devspec_show(struct device *, struct device_attribute *, char *);
981 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
982 			     char *buf);
983 
984 static struct device_attribute dev_attr_name;
985 static struct device_attribute dev_attr_devspec;
986 static struct device_attribute dev_attr_modalias;
987 
988 static DEVICE_ATTR_RO(cmo_entitled);
989 static DEVICE_ATTR_RO(cmo_allocated);
990 static DEVICE_ATTR_RW(cmo_desired);
991 static DEVICE_ATTR_RW(cmo_allocs_failed);
992 
993 static struct attribute *vio_cmo_dev_attrs[] = {
994 	&dev_attr_name.attr,
995 	&dev_attr_devspec.attr,
996 	&dev_attr_modalias.attr,
997 	&dev_attr_cmo_entitled.attr,
998 	&dev_attr_cmo_allocated.attr,
999 	&dev_attr_cmo_desired.attr,
1000 	&dev_attr_cmo_allocs_failed.attr,
1001 	NULL,
1002 };
1003 ATTRIBUTE_GROUPS(vio_cmo_dev);
1004 
1005 /* sysfs bus functions and data structures for CMO */
1006 
1007 #define viobus_cmo_rd_attr(name)                                        \
1008 static ssize_t cmo_bus_##name##_show(struct bus_type *bt, char *buf)    \
1009 {                                                                       \
1010 	return sprintf(buf, "%lu\n", vio_cmo.name);                     \
1011 }                                                                       \
1012 static struct bus_attribute bus_attr_cmo_bus_##name =			\
1013 	__ATTR(cmo_##name, S_IRUGO, cmo_bus_##name##_show, NULL)
1014 
1015 #define viobus_cmo_pool_rd_attr(name, var)                              \
1016 static ssize_t                                                          \
1017 cmo_##name##_##var##_show(struct bus_type *bt, char *buf)               \
1018 {                                                                       \
1019 	return sprintf(buf, "%lu\n", vio_cmo.name.var);                 \
1020 }                                                                       \
1021 static BUS_ATTR_RO(cmo_##name##_##var)
1022 
1023 viobus_cmo_rd_attr(entitled);
1024 viobus_cmo_rd_attr(spare);
1025 viobus_cmo_rd_attr(min);
1026 viobus_cmo_rd_attr(desired);
1027 viobus_cmo_rd_attr(curr);
1028 viobus_cmo_pool_rd_attr(reserve, size);
1029 viobus_cmo_pool_rd_attr(excess, size);
1030 viobus_cmo_pool_rd_attr(excess, free);
1031 
1032 static ssize_t cmo_high_show(struct bus_type *bt, char *buf)
1033 {
1034 	return sprintf(buf, "%lu\n", vio_cmo.high);
1035 }
1036 
1037 static ssize_t cmo_high_store(struct bus_type *bt, const char *buf,
1038 			      size_t count)
1039 {
1040 	unsigned long flags;
1041 
1042 	spin_lock_irqsave(&vio_cmo.lock, flags);
1043 	vio_cmo.high = vio_cmo.curr;
1044 	spin_unlock_irqrestore(&vio_cmo.lock, flags);
1045 
1046 	return count;
1047 }
1048 static BUS_ATTR_RW(cmo_high);
1049 
1050 static struct attribute *vio_bus_attrs[] = {
1051 	&bus_attr_cmo_bus_entitled.attr,
1052 	&bus_attr_cmo_bus_spare.attr,
1053 	&bus_attr_cmo_bus_min.attr,
1054 	&bus_attr_cmo_bus_desired.attr,
1055 	&bus_attr_cmo_bus_curr.attr,
1056 	&bus_attr_cmo_high.attr,
1057 	&bus_attr_cmo_reserve_size.attr,
1058 	&bus_attr_cmo_excess_size.attr,
1059 	&bus_attr_cmo_excess_free.attr,
1060 	NULL,
1061 };
1062 ATTRIBUTE_GROUPS(vio_bus);
1063 
1064 static void __init vio_cmo_sysfs_init(void)
1065 {
1066 	vio_bus_type.dev_groups = vio_cmo_dev_groups;
1067 	vio_bus_type.bus_groups = vio_bus_groups;
1068 }
1069 #else /* CONFIG_PPC_SMLPAR */
1070 int vio_cmo_entitlement_update(size_t new_entitlement) { return 0; }
1071 void vio_cmo_set_dev_desired(struct vio_dev *viodev, size_t desired) {}
1072 static int vio_cmo_bus_probe(struct vio_dev *viodev) { return 0; }
1073 static void vio_cmo_bus_remove(struct vio_dev *viodev) {}
1074 static void vio_cmo_set_dma_ops(struct vio_dev *viodev) {}
1075 static void vio_cmo_bus_init(void) {}
1076 static void __init vio_cmo_sysfs_init(void) { }
1077 #endif /* CONFIG_PPC_SMLPAR */
1078 EXPORT_SYMBOL(vio_cmo_entitlement_update);
1079 EXPORT_SYMBOL(vio_cmo_set_dev_desired);
1080 
1081 
1082 /*
1083  * Platform Facilities Option (PFO) support
1084  */
1085 
1086 /**
1087  * vio_h_cop_sync - Perform a synchronous PFO co-processor operation
1088  *
1089  * @vdev - Pointer to a struct vio_dev for device
1090  * @op - Pointer to a struct vio_pfo_op for the operation parameters
1091  *
1092  * Calls the hypervisor to synchronously perform the PFO operation
1093  * described in @op.  In the case of a busy response from the hypervisor,
1094  * the operation will be re-submitted indefinitely unless a non-zero timeout
1095  * is specified or an error occurs. The timeout places a limit on when to
1096  * stop re-submitting a operation, the total time can be exceeded if an
1097  * operation is in progress.
1098  *
1099  * If op->hcall_ret is not NULL, this will be set to the return from the
1100  * last h_cop_op call or it will be 0 if an error not involving the h_call
1101  * was encountered.
1102  *
1103  * Returns:
1104  *	0 on success,
1105  *	-EINVAL if the h_call fails due to an invalid parameter,
1106  *	-E2BIG if the h_call can not be performed synchronously,
1107  *	-EBUSY if a timeout is specified and has elapsed,
1108  *	-EACCES if the memory area for data/status has been rescinded, or
1109  *	-EPERM if a hardware fault has been indicated
1110  */
1111 int vio_h_cop_sync(struct vio_dev *vdev, struct vio_pfo_op *op)
1112 {
1113 	struct device *dev = &vdev->dev;
1114 	unsigned long deadline = 0;
1115 	long hret = 0;
1116 	int ret = 0;
1117 
1118 	if (op->timeout)
1119 		deadline = jiffies + msecs_to_jiffies(op->timeout);
1120 
1121 	while (true) {
1122 		hret = plpar_hcall_norets(H_COP, op->flags,
1123 				vdev->resource_id,
1124 				op->in, op->inlen, op->out,
1125 				op->outlen, op->csbcpb);
1126 
1127 		if (hret == H_SUCCESS ||
1128 		    (hret != H_NOT_ENOUGH_RESOURCES &&
1129 		     hret != H_BUSY && hret != H_RESOURCE) ||
1130 		    (op->timeout && time_after(deadline, jiffies)))
1131 			break;
1132 
1133 		dev_dbg(dev, "%s: hcall ret(%ld), retrying.\n", __func__, hret);
1134 	}
1135 
1136 	switch (hret) {
1137 	case H_SUCCESS:
1138 		ret = 0;
1139 		break;
1140 	case H_OP_MODE:
1141 	case H_TOO_BIG:
1142 		ret = -E2BIG;
1143 		break;
1144 	case H_RESCINDED:
1145 		ret = -EACCES;
1146 		break;
1147 	case H_HARDWARE:
1148 		ret = -EPERM;
1149 		break;
1150 	case H_NOT_ENOUGH_RESOURCES:
1151 	case H_RESOURCE:
1152 	case H_BUSY:
1153 		ret = -EBUSY;
1154 		break;
1155 	default:
1156 		ret = -EINVAL;
1157 		break;
1158 	}
1159 
1160 	if (ret)
1161 		dev_dbg(dev, "%s: Sync h_cop_op failure (ret:%d) (hret:%ld)\n",
1162 				__func__, ret, hret);
1163 
1164 	op->hcall_err = hret;
1165 	return ret;
1166 }
1167 EXPORT_SYMBOL(vio_h_cop_sync);
1168 
1169 static struct iommu_table *vio_build_iommu_table(struct vio_dev *dev)
1170 {
1171 	const __be32 *dma_window;
1172 	struct iommu_table *tbl;
1173 	unsigned long offset, size;
1174 
1175 	dma_window = of_get_property(dev->dev.of_node,
1176 				  "ibm,my-dma-window", NULL);
1177 	if (!dma_window)
1178 		return NULL;
1179 
1180 	tbl = kzalloc(sizeof(*tbl), GFP_KERNEL);
1181 	if (tbl == NULL)
1182 		return NULL;
1183 
1184 	kref_init(&tbl->it_kref);
1185 
1186 	of_parse_dma_window(dev->dev.of_node, dma_window,
1187 			    &tbl->it_index, &offset, &size);
1188 
1189 	/* TCE table size - measured in tce entries */
1190 	tbl->it_page_shift = IOMMU_PAGE_SHIFT_4K;
1191 	tbl->it_size = size >> tbl->it_page_shift;
1192 	/* offset for VIO should always be 0 */
1193 	tbl->it_offset = offset >> tbl->it_page_shift;
1194 	tbl->it_busno = 0;
1195 	tbl->it_type = TCE_VB;
1196 	tbl->it_blocksize = 16;
1197 
1198 	if (firmware_has_feature(FW_FEATURE_LPAR))
1199 		tbl->it_ops = &iommu_table_lpar_multi_ops;
1200 	else
1201 		tbl->it_ops = &iommu_table_pseries_ops;
1202 
1203 	return iommu_init_table(tbl, -1, 0, 0);
1204 }
1205 
1206 /**
1207  * vio_match_device: - Tell if a VIO device has a matching
1208  *			VIO device id structure.
1209  * @ids:	array of VIO device id structures to search in
1210  * @dev:	the VIO device structure to match against
1211  *
1212  * Used by a driver to check whether a VIO device present in the
1213  * system is in its list of supported devices. Returns the matching
1214  * vio_device_id structure or NULL if there is no match.
1215  */
1216 static const struct vio_device_id *vio_match_device(
1217 		const struct vio_device_id *ids, const struct vio_dev *dev)
1218 {
1219 	while (ids->type[0] != '\0') {
1220 		if ((strncmp(dev->type, ids->type, strlen(ids->type)) == 0) &&
1221 		    of_device_is_compatible(dev->dev.of_node,
1222 					 ids->compat))
1223 			return ids;
1224 		ids++;
1225 	}
1226 	return NULL;
1227 }
1228 
1229 /*
1230  * Convert from struct device to struct vio_dev and pass to driver.
1231  * dev->driver has already been set by generic code because vio_bus_match
1232  * succeeded.
1233  */
1234 static int vio_bus_probe(struct device *dev)
1235 {
1236 	struct vio_dev *viodev = to_vio_dev(dev);
1237 	struct vio_driver *viodrv = to_vio_driver(dev->driver);
1238 	const struct vio_device_id *id;
1239 	int error = -ENODEV;
1240 
1241 	if (!viodrv->probe)
1242 		return error;
1243 
1244 	id = vio_match_device(viodrv->id_table, viodev);
1245 	if (id) {
1246 		memset(&viodev->cmo, 0, sizeof(viodev->cmo));
1247 		if (firmware_has_feature(FW_FEATURE_CMO)) {
1248 			error = vio_cmo_bus_probe(viodev);
1249 			if (error)
1250 				return error;
1251 		}
1252 		error = viodrv->probe(viodev, id);
1253 		if (error && firmware_has_feature(FW_FEATURE_CMO))
1254 			vio_cmo_bus_remove(viodev);
1255 	}
1256 
1257 	return error;
1258 }
1259 
1260 /* convert from struct device to struct vio_dev and pass to driver. */
1261 static void vio_bus_remove(struct device *dev)
1262 {
1263 	struct vio_dev *viodev = to_vio_dev(dev);
1264 	struct vio_driver *viodrv = to_vio_driver(dev->driver);
1265 	struct device *devptr;
1266 
1267 	/*
1268 	 * Hold a reference to the device after the remove function is called
1269 	 * to allow for CMO accounting cleanup for the device.
1270 	 */
1271 	devptr = get_device(dev);
1272 
1273 	if (viodrv->remove)
1274 		viodrv->remove(viodev);
1275 
1276 	if (firmware_has_feature(FW_FEATURE_CMO))
1277 		vio_cmo_bus_remove(viodev);
1278 
1279 	put_device(devptr);
1280 }
1281 
1282 static void vio_bus_shutdown(struct device *dev)
1283 {
1284 	struct vio_dev *viodev = to_vio_dev(dev);
1285 	struct vio_driver *viodrv;
1286 
1287 	if (dev->driver) {
1288 		viodrv = to_vio_driver(dev->driver);
1289 		if (viodrv->shutdown)
1290 			viodrv->shutdown(viodev);
1291 		else if (kexec_in_progress)
1292 			vio_bus_remove(dev);
1293 	}
1294 }
1295 
1296 /**
1297  * vio_register_driver: - Register a new vio driver
1298  * @viodrv:	The vio_driver structure to be registered.
1299  */
1300 int __vio_register_driver(struct vio_driver *viodrv, struct module *owner,
1301 			  const char *mod_name)
1302 {
1303 	// vio_bus_type is only initialised for pseries
1304 	if (!machine_is(pseries))
1305 		return -ENODEV;
1306 
1307 	pr_debug("%s: driver %s registering\n", __func__, viodrv->name);
1308 
1309 	/* fill in 'struct driver' fields */
1310 	viodrv->driver.name = viodrv->name;
1311 	viodrv->driver.pm = viodrv->pm;
1312 	viodrv->driver.bus = &vio_bus_type;
1313 	viodrv->driver.owner = owner;
1314 	viodrv->driver.mod_name = mod_name;
1315 
1316 	return driver_register(&viodrv->driver);
1317 }
1318 EXPORT_SYMBOL(__vio_register_driver);
1319 
1320 /**
1321  * vio_unregister_driver - Remove registration of vio driver.
1322  * @viodrv:	The vio_driver struct to be removed form registration
1323  */
1324 void vio_unregister_driver(struct vio_driver *viodrv)
1325 {
1326 	driver_unregister(&viodrv->driver);
1327 }
1328 EXPORT_SYMBOL(vio_unregister_driver);
1329 
1330 /* vio_dev refcount hit 0 */
1331 static void vio_dev_release(struct device *dev)
1332 {
1333 	struct iommu_table *tbl = get_iommu_table_base(dev);
1334 
1335 	if (tbl)
1336 		iommu_tce_table_put(tbl);
1337 	of_node_put(dev->of_node);
1338 	kfree(to_vio_dev(dev));
1339 }
1340 
1341 /**
1342  * vio_register_device_node: - Register a new vio device.
1343  * @of_node:	The OF node for this device.
1344  *
1345  * Creates and initializes a vio_dev structure from the data in
1346  * of_node and adds it to the list of virtual devices.
1347  * Returns a pointer to the created vio_dev or NULL if node has
1348  * NULL device_type or compatible fields.
1349  */
1350 struct vio_dev *vio_register_device_node(struct device_node *of_node)
1351 {
1352 	struct vio_dev *viodev;
1353 	struct device_node *parent_node;
1354 	const __be32 *prop;
1355 	enum vio_dev_family family;
1356 
1357 	/*
1358 	 * Determine if this node is a under the /vdevice node or under the
1359 	 * /ibm,platform-facilities node.  This decides the device's family.
1360 	 */
1361 	parent_node = of_get_parent(of_node);
1362 	if (parent_node) {
1363 		if (of_node_is_type(parent_node, "ibm,platform-facilities"))
1364 			family = PFO;
1365 		else if (of_node_is_type(parent_node, "vdevice"))
1366 			family = VDEVICE;
1367 		else {
1368 			pr_warn("%s: parent(%pOF) of %pOFn not recognized.\n",
1369 					__func__,
1370 					parent_node,
1371 					of_node);
1372 			of_node_put(parent_node);
1373 			return NULL;
1374 		}
1375 		of_node_put(parent_node);
1376 	} else {
1377 		pr_warn("%s: could not determine the parent of node %pOFn.\n",
1378 				__func__, of_node);
1379 		return NULL;
1380 	}
1381 
1382 	if (family == PFO) {
1383 		if (of_get_property(of_node, "interrupt-controller", NULL)) {
1384 			pr_debug("%s: Skipping the interrupt controller %pOFn.\n",
1385 					__func__, of_node);
1386 			return NULL;
1387 		}
1388 	}
1389 
1390 	/* allocate a vio_dev for this node */
1391 	viodev = kzalloc(sizeof(struct vio_dev), GFP_KERNEL);
1392 	if (viodev == NULL) {
1393 		pr_warn("%s: allocation failure for VIO device.\n", __func__);
1394 		return NULL;
1395 	}
1396 
1397 	/* we need the 'device_type' property, in order to match with drivers */
1398 	viodev->family = family;
1399 	if (viodev->family == VDEVICE) {
1400 		unsigned int unit_address;
1401 
1402 		viodev->type = of_node_get_device_type(of_node);
1403 		if (!viodev->type) {
1404 			pr_warn("%s: node %pOFn is missing the 'device_type' "
1405 					"property.\n", __func__, of_node);
1406 			goto out;
1407 		}
1408 
1409 		prop = of_get_property(of_node, "reg", NULL);
1410 		if (prop == NULL) {
1411 			pr_warn("%s: node %pOFn missing 'reg'\n",
1412 					__func__, of_node);
1413 			goto out;
1414 		}
1415 		unit_address = of_read_number(prop, 1);
1416 		dev_set_name(&viodev->dev, "%x", unit_address);
1417 		viodev->irq = irq_of_parse_and_map(of_node, 0);
1418 		viodev->unit_address = unit_address;
1419 	} else {
1420 		/* PFO devices need their resource_id for submitting COP_OPs
1421 		 * This is an optional field for devices, but is required when
1422 		 * performing synchronous ops */
1423 		prop = of_get_property(of_node, "ibm,resource-id", NULL);
1424 		if (prop != NULL)
1425 			viodev->resource_id = of_read_number(prop, 1);
1426 
1427 		dev_set_name(&viodev->dev, "%pOFn", of_node);
1428 		viodev->type = dev_name(&viodev->dev);
1429 		viodev->irq = 0;
1430 	}
1431 
1432 	viodev->name = of_node->name;
1433 	viodev->dev.of_node = of_node_get(of_node);
1434 
1435 	set_dev_node(&viodev->dev, of_node_to_nid(of_node));
1436 
1437 	/* init generic 'struct device' fields: */
1438 	viodev->dev.parent = &vio_bus_device.dev;
1439 	viodev->dev.bus = &vio_bus_type;
1440 	viodev->dev.release = vio_dev_release;
1441 
1442 	if (of_get_property(viodev->dev.of_node, "ibm,my-dma-window", NULL)) {
1443 		if (firmware_has_feature(FW_FEATURE_CMO))
1444 			vio_cmo_set_dma_ops(viodev);
1445 		else
1446 			set_dma_ops(&viodev->dev, &dma_iommu_ops);
1447 
1448 		set_iommu_table_base(&viodev->dev,
1449 				     vio_build_iommu_table(viodev));
1450 
1451 		/* needed to ensure proper operation of coherent allocations
1452 		 * later, in case driver doesn't set it explicitly */
1453 		viodev->dev.coherent_dma_mask = DMA_BIT_MASK(64);
1454 		viodev->dev.dma_mask = &viodev->dev.coherent_dma_mask;
1455 	}
1456 
1457 	/* register with generic device framework */
1458 	if (device_register(&viodev->dev)) {
1459 		printk(KERN_ERR "%s: failed to register device %s\n",
1460 				__func__, dev_name(&viodev->dev));
1461 		put_device(&viodev->dev);
1462 		return NULL;
1463 	}
1464 
1465 	return viodev;
1466 
1467 out:	/* Use this exit point for any return prior to device_register */
1468 	kfree(viodev);
1469 
1470 	return NULL;
1471 }
1472 EXPORT_SYMBOL(vio_register_device_node);
1473 
1474 /*
1475  * vio_bus_scan_for_devices - Scan OF and register each child device
1476  * @root_name - OF node name for the root of the subtree to search.
1477  *		This must be non-NULL
1478  *
1479  * Starting from the root node provide, register the device node for
1480  * each child beneath the root.
1481  */
1482 static void __init vio_bus_scan_register_devices(char *root_name)
1483 {
1484 	struct device_node *node_root, *node_child;
1485 
1486 	if (!root_name)
1487 		return;
1488 
1489 	node_root = of_find_node_by_name(NULL, root_name);
1490 	if (node_root) {
1491 
1492 		/*
1493 		 * Create struct vio_devices for each virtual device in
1494 		 * the device tree. Drivers will associate with them later.
1495 		 */
1496 		node_child = of_get_next_child(node_root, NULL);
1497 		while (node_child) {
1498 			vio_register_device_node(node_child);
1499 			node_child = of_get_next_child(node_root, node_child);
1500 		}
1501 		of_node_put(node_root);
1502 	}
1503 }
1504 
1505 /**
1506  * vio_bus_init: - Initialize the virtual IO bus
1507  */
1508 static int __init vio_bus_init(void)
1509 {
1510 	int err;
1511 
1512 	if (firmware_has_feature(FW_FEATURE_CMO))
1513 		vio_cmo_sysfs_init();
1514 
1515 	err = bus_register(&vio_bus_type);
1516 	if (err) {
1517 		printk(KERN_ERR "failed to register VIO bus\n");
1518 		return err;
1519 	}
1520 
1521 	/*
1522 	 * The fake parent of all vio devices, just to give us
1523 	 * a nice directory
1524 	 */
1525 	err = device_register(&vio_bus_device.dev);
1526 	if (err) {
1527 		printk(KERN_WARNING "%s: device_register returned %i\n",
1528 				__func__, err);
1529 		return err;
1530 	}
1531 
1532 	if (firmware_has_feature(FW_FEATURE_CMO))
1533 		vio_cmo_bus_init();
1534 
1535 	return 0;
1536 }
1537 machine_postcore_initcall(pseries, vio_bus_init);
1538 
1539 static int __init vio_device_init(void)
1540 {
1541 	vio_bus_scan_register_devices("vdevice");
1542 	vio_bus_scan_register_devices("ibm,platform-facilities");
1543 
1544 	return 0;
1545 }
1546 machine_device_initcall(pseries, vio_device_init);
1547 
1548 static ssize_t name_show(struct device *dev,
1549 		struct device_attribute *attr, char *buf)
1550 {
1551 	return sprintf(buf, "%s\n", to_vio_dev(dev)->name);
1552 }
1553 static DEVICE_ATTR_RO(name);
1554 
1555 static ssize_t devspec_show(struct device *dev,
1556 		struct device_attribute *attr, char *buf)
1557 {
1558 	struct device_node *of_node = dev->of_node;
1559 
1560 	return sprintf(buf, "%pOF\n", of_node);
1561 }
1562 static DEVICE_ATTR_RO(devspec);
1563 
1564 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
1565 			     char *buf)
1566 {
1567 	const struct vio_dev *vio_dev = to_vio_dev(dev);
1568 	struct device_node *dn;
1569 	const char *cp;
1570 
1571 	dn = dev->of_node;
1572 	if (!dn) {
1573 		strcpy(buf, "\n");
1574 		return strlen(buf);
1575 	}
1576 	cp = of_get_property(dn, "compatible", NULL);
1577 	if (!cp) {
1578 		strcpy(buf, "\n");
1579 		return strlen(buf);
1580 	}
1581 
1582 	return sprintf(buf, "vio:T%sS%s\n", vio_dev->type, cp);
1583 }
1584 static DEVICE_ATTR_RO(modalias);
1585 
1586 static struct attribute *vio_dev_attrs[] = {
1587 	&dev_attr_name.attr,
1588 	&dev_attr_devspec.attr,
1589 	&dev_attr_modalias.attr,
1590 	NULL,
1591 };
1592 ATTRIBUTE_GROUPS(vio_dev);
1593 
1594 void vio_unregister_device(struct vio_dev *viodev)
1595 {
1596 	device_unregister(&viodev->dev);
1597 	if (viodev->family == VDEVICE)
1598 		irq_dispose_mapping(viodev->irq);
1599 }
1600 EXPORT_SYMBOL(vio_unregister_device);
1601 
1602 static int vio_bus_match(struct device *dev, struct device_driver *drv)
1603 {
1604 	const struct vio_dev *vio_dev = to_vio_dev(dev);
1605 	struct vio_driver *vio_drv = to_vio_driver(drv);
1606 	const struct vio_device_id *ids = vio_drv->id_table;
1607 
1608 	return (ids != NULL) && (vio_match_device(ids, vio_dev) != NULL);
1609 }
1610 
1611 static int vio_hotplug(struct device *dev, struct kobj_uevent_env *env)
1612 {
1613 	const struct vio_dev *vio_dev = to_vio_dev(dev);
1614 	struct device_node *dn;
1615 	const char *cp;
1616 
1617 	dn = dev->of_node;
1618 	if (!dn)
1619 		return -ENODEV;
1620 	cp = of_get_property(dn, "compatible", NULL);
1621 	if (!cp)
1622 		return -ENODEV;
1623 
1624 	add_uevent_var(env, "MODALIAS=vio:T%sS%s", vio_dev->type, cp);
1625 	return 0;
1626 }
1627 
1628 struct bus_type vio_bus_type = {
1629 	.name = "vio",
1630 	.dev_groups = vio_dev_groups,
1631 	.uevent = vio_hotplug,
1632 	.match = vio_bus_match,
1633 	.probe = vio_bus_probe,
1634 	.remove = vio_bus_remove,
1635 	.shutdown = vio_bus_shutdown,
1636 };
1637 
1638 /**
1639  * vio_get_attribute: - get attribute for virtual device
1640  * @vdev:	The vio device to get property.
1641  * @which:	The property/attribute to be extracted.
1642  * @length:	Pointer to length of returned data size (unused if NULL).
1643  *
1644  * Calls prom.c's of_get_property() to return the value of the
1645  * attribute specified by @which
1646 */
1647 const void *vio_get_attribute(struct vio_dev *vdev, char *which, int *length)
1648 {
1649 	return of_get_property(vdev->dev.of_node, which, length);
1650 }
1651 EXPORT_SYMBOL(vio_get_attribute);
1652 
1653 /* vio_find_name() - internal because only vio.c knows how we formatted the
1654  * kobject name
1655  */
1656 static struct vio_dev *vio_find_name(const char *name)
1657 {
1658 	struct device *found;
1659 
1660 	found = bus_find_device_by_name(&vio_bus_type, NULL, name);
1661 	if (!found)
1662 		return NULL;
1663 
1664 	return to_vio_dev(found);
1665 }
1666 
1667 /**
1668  * vio_find_node - find an already-registered vio_dev
1669  * @vnode: device_node of the virtual device we're looking for
1670  *
1671  * Takes a reference to the embedded struct device which needs to be dropped
1672  * after use.
1673  */
1674 struct vio_dev *vio_find_node(struct device_node *vnode)
1675 {
1676 	char kobj_name[20];
1677 	struct device_node *vnode_parent;
1678 
1679 	vnode_parent = of_get_parent(vnode);
1680 	if (!vnode_parent)
1681 		return NULL;
1682 
1683 	/* construct the kobject name from the device node */
1684 	if (of_node_is_type(vnode_parent, "vdevice")) {
1685 		const __be32 *prop;
1686 
1687 		prop = of_get_property(vnode, "reg", NULL);
1688 		if (!prop)
1689 			goto out;
1690 		snprintf(kobj_name, sizeof(kobj_name), "%x",
1691 			 (uint32_t)of_read_number(prop, 1));
1692 	} else if (of_node_is_type(vnode_parent, "ibm,platform-facilities"))
1693 		snprintf(kobj_name, sizeof(kobj_name), "%pOFn", vnode);
1694 	else
1695 		goto out;
1696 
1697 	of_node_put(vnode_parent);
1698 	return vio_find_name(kobj_name);
1699 out:
1700 	of_node_put(vnode_parent);
1701 	return NULL;
1702 }
1703 EXPORT_SYMBOL(vio_find_node);
1704 
1705 int vio_enable_interrupts(struct vio_dev *dev)
1706 {
1707 	int rc = h_vio_signal(dev->unit_address, VIO_IRQ_ENABLE);
1708 	if (rc != H_SUCCESS)
1709 		printk(KERN_ERR "vio: Error 0x%x enabling interrupts\n", rc);
1710 	return rc;
1711 }
1712 EXPORT_SYMBOL(vio_enable_interrupts);
1713 
1714 int vio_disable_interrupts(struct vio_dev *dev)
1715 {
1716 	int rc = h_vio_signal(dev->unit_address, VIO_IRQ_DISABLE);
1717 	if (rc != H_SUCCESS)
1718 		printk(KERN_ERR "vio: Error 0x%x disabling interrupts\n", rc);
1719 	return rc;
1720 }
1721 EXPORT_SYMBOL(vio_disable_interrupts);
1722 
1723 static int __init vio_init(void)
1724 {
1725 	dma_debug_add_bus(&vio_bus_type);
1726 	return 0;
1727 }
1728 machine_fs_initcall(pseries, vio_init);
1729