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 #include <linux/of_irq.h>
27 
28 #include <asm/iommu.h>
29 #include <asm/dma.h>
30 #include <asm/vio.h>
31 #include <asm/prom.h>
32 #include <asm/firmware.h>
33 #include <asm/tce.h>
34 #include <asm/page.h>
35 #include <asm/hvcall.h>
36 #include <asm/machdep.h>
37 
38 static struct vio_dev vio_bus_device  = { /* fake "parent" device */
39 	.name = "vio",
40 	.type = "",
41 	.dev.init_name = "vio",
42 	.dev.bus = &vio_bus_type,
43 };
44 
45 #ifdef CONFIG_PPC_SMLPAR
46 /**
47  * vio_cmo_pool - A pool of IO memory for CMO use
48  *
49  * @size: The size of the pool in bytes
50  * @free: The amount of free memory in the pool
51  */
52 struct vio_cmo_pool {
53 	size_t size;
54 	size_t free;
55 };
56 
57 /* How many ms to delay queued balance work */
58 #define VIO_CMO_BALANCE_DELAY 100
59 
60 /* Portion out IO memory to CMO devices by this chunk size */
61 #define VIO_CMO_BALANCE_CHUNK 131072
62 
63 /**
64  * vio_cmo_dev_entry - A device that is CMO-enabled and requires entitlement
65  *
66  * @vio_dev: struct vio_dev pointer
67  * @list: pointer to other devices on bus that are being tracked
68  */
69 struct vio_cmo_dev_entry {
70 	struct vio_dev *viodev;
71 	struct list_head list;
72 };
73 
74 /**
75  * vio_cmo - VIO bus accounting structure for CMO entitlement
76  *
77  * @lock: spinlock for entire structure
78  * @balance_q: work queue for balancing system entitlement
79  * @device_list: list of CMO-enabled devices requiring entitlement
80  * @entitled: total system entitlement in bytes
81  * @reserve: pool of memory from which devices reserve entitlement, incl. spare
82  * @excess: pool of excess entitlement not needed for device reserves or spare
83  * @spare: IO memory for device hotplug functionality
84  * @min: minimum necessary for system operation
85  * @desired: desired memory for system operation
86  * @curr: bytes currently allocated
87  * @high: high water mark for IO data usage
88  */
89 static struct vio_cmo {
90 	spinlock_t lock;
91 	struct delayed_work balance_q;
92 	struct list_head device_list;
93 	size_t entitled;
94 	struct vio_cmo_pool reserve;
95 	struct vio_cmo_pool excess;
96 	size_t spare;
97 	size_t min;
98 	size_t desired;
99 	size_t curr;
100 	size_t high;
101 } vio_cmo;
102 
103 /**
104  * vio_cmo_OF_devices - Count the number of OF devices that have DMA windows
105  */
106 static int vio_cmo_num_OF_devs(void)
107 {
108 	struct device_node *node_vroot;
109 	int count = 0;
110 
111 	/*
112 	 * Count the number of vdevice entries with an
113 	 * ibm,my-dma-window OF property
114 	 */
115 	node_vroot = of_find_node_by_name(NULL, "vdevice");
116 	if (node_vroot) {
117 		struct device_node *of_node;
118 		struct property *prop;
119 
120 		for_each_child_of_node(node_vroot, of_node) {
121 			prop = of_find_property(of_node, "ibm,my-dma-window",
122 			                       NULL);
123 			if (prop)
124 				count++;
125 		}
126 	}
127 	of_node_put(node_vroot);
128 	return count;
129 }
130 
131 /**
132  * vio_cmo_alloc - allocate IO memory for CMO-enable devices
133  *
134  * @viodev: VIO device requesting IO memory
135  * @size: size of allocation requested
136  *
137  * Allocations come from memory reserved for the devices and any excess
138  * IO memory available to all devices.  The spare pool used to service
139  * hotplug must be equal to %VIO_CMO_MIN_ENT for the excess pool to be
140  * made available.
141  *
142  * Return codes:
143  *  0 for successful allocation and -ENOMEM for a failure
144  */
145 static inline int vio_cmo_alloc(struct vio_dev *viodev, size_t size)
146 {
147 	unsigned long flags;
148 	size_t reserve_free = 0;
149 	size_t excess_free = 0;
150 	int ret = -ENOMEM;
151 
152 	spin_lock_irqsave(&vio_cmo.lock, flags);
153 
154 	/* Determine the amount of free entitlement available in reserve */
155 	if (viodev->cmo.entitled > viodev->cmo.allocated)
156 		reserve_free = viodev->cmo.entitled - viodev->cmo.allocated;
157 
158 	/* If spare is not fulfilled, the excess pool can not be used. */
159 	if (vio_cmo.spare >= VIO_CMO_MIN_ENT)
160 		excess_free = vio_cmo.excess.free;
161 
162 	/* The request can be satisfied */
163 	if ((reserve_free + excess_free) >= size) {
164 		vio_cmo.curr += size;
165 		if (vio_cmo.curr > vio_cmo.high)
166 			vio_cmo.high = vio_cmo.curr;
167 		viodev->cmo.allocated += size;
168 		size -= min(reserve_free, size);
169 		vio_cmo.excess.free -= size;
170 		ret = 0;
171 	}
172 
173 	spin_unlock_irqrestore(&vio_cmo.lock, flags);
174 	return ret;
175 }
176 
177 /**
178  * vio_cmo_dealloc - deallocate IO memory from CMO-enable devices
179  * @viodev: VIO device freeing IO memory
180  * @size: size of deallocation
181  *
182  * IO memory is freed by the device back to the correct memory pools.
183  * The spare pool is replenished first from either memory pool, then
184  * the reserve pool is used to reduce device entitlement, the excess
185  * pool is used to increase the reserve pool toward the desired entitlement
186  * target, and then the remaining memory is returned to the pools.
187  *
188  */
189 static inline void vio_cmo_dealloc(struct vio_dev *viodev, size_t size)
190 {
191 	unsigned long flags;
192 	size_t spare_needed = 0;
193 	size_t excess_freed = 0;
194 	size_t reserve_freed = size;
195 	size_t tmp;
196 	int balance = 0;
197 
198 	spin_lock_irqsave(&vio_cmo.lock, flags);
199 	vio_cmo.curr -= size;
200 
201 	/* Amount of memory freed from the excess pool */
202 	if (viodev->cmo.allocated > viodev->cmo.entitled) {
203 		excess_freed = min(reserve_freed, (viodev->cmo.allocated -
204 		                                   viodev->cmo.entitled));
205 		reserve_freed -= excess_freed;
206 	}
207 
208 	/* Remove allocation from device */
209 	viodev->cmo.allocated -= (reserve_freed + excess_freed);
210 
211 	/* Spare is a subset of the reserve pool, replenish it first. */
212 	spare_needed = VIO_CMO_MIN_ENT - vio_cmo.spare;
213 
214 	/*
215 	 * Replenish the spare in the reserve pool from the excess pool.
216 	 * This moves entitlement into the reserve pool.
217 	 */
218 	if (spare_needed && excess_freed) {
219 		tmp = min(excess_freed, spare_needed);
220 		vio_cmo.excess.size -= tmp;
221 		vio_cmo.reserve.size += tmp;
222 		vio_cmo.spare += tmp;
223 		excess_freed -= tmp;
224 		spare_needed -= tmp;
225 		balance = 1;
226 	}
227 
228 	/*
229 	 * Replenish the spare in the reserve pool from the reserve pool.
230 	 * This removes entitlement from the device down to VIO_CMO_MIN_ENT,
231 	 * if needed, and gives it to the spare pool. The amount of used
232 	 * memory in this pool does not change.
233 	 */
234 	if (spare_needed && reserve_freed) {
235 		tmp = min3(spare_needed, reserve_freed, (viodev->cmo.entitled - VIO_CMO_MIN_ENT));
236 
237 		vio_cmo.spare += tmp;
238 		viodev->cmo.entitled -= tmp;
239 		reserve_freed -= tmp;
240 		spare_needed -= tmp;
241 		balance = 1;
242 	}
243 
244 	/*
245 	 * Increase the reserve pool until the desired allocation is met.
246 	 * Move an allocation freed from the excess pool into the reserve
247 	 * pool and schedule a balance operation.
248 	 */
249 	if (excess_freed && (vio_cmo.desired > vio_cmo.reserve.size)) {
250 		tmp = min(excess_freed, (vio_cmo.desired - vio_cmo.reserve.size));
251 
252 		vio_cmo.excess.size -= tmp;
253 		vio_cmo.reserve.size += tmp;
254 		excess_freed -= tmp;
255 		balance = 1;
256 	}
257 
258 	/* Return memory from the excess pool to that pool */
259 	if (excess_freed)
260 		vio_cmo.excess.free += excess_freed;
261 
262 	if (balance)
263 		schedule_delayed_work(&vio_cmo.balance_q, VIO_CMO_BALANCE_DELAY);
264 	spin_unlock_irqrestore(&vio_cmo.lock, flags);
265 }
266 
267 /**
268  * vio_cmo_entitlement_update - Manage system entitlement changes
269  *
270  * @new_entitlement: new system entitlement to attempt to accommodate
271  *
272  * Increases in entitlement will be used to fulfill the spare entitlement
273  * and the rest is given to the excess pool.  Decreases, if they are
274  * possible, come from the excess pool and from unused device entitlement
275  *
276  * Returns: 0 on success, -ENOMEM when change can not be made
277  */
278 int vio_cmo_entitlement_update(size_t new_entitlement)
279 {
280 	struct vio_dev *viodev;
281 	struct vio_cmo_dev_entry *dev_ent;
282 	unsigned long flags;
283 	size_t avail, delta, tmp;
284 
285 	spin_lock_irqsave(&vio_cmo.lock, flags);
286 
287 	/* Entitlement increases */
288 	if (new_entitlement > vio_cmo.entitled) {
289 		delta = new_entitlement - vio_cmo.entitled;
290 
291 		/* Fulfill spare allocation */
292 		if (vio_cmo.spare < VIO_CMO_MIN_ENT) {
293 			tmp = min(delta, (VIO_CMO_MIN_ENT - vio_cmo.spare));
294 			vio_cmo.spare += tmp;
295 			vio_cmo.reserve.size += tmp;
296 			delta -= tmp;
297 		}
298 
299 		/* Remaining new allocation goes to the excess pool */
300 		vio_cmo.entitled += delta;
301 		vio_cmo.excess.size += delta;
302 		vio_cmo.excess.free += delta;
303 
304 		goto out;
305 	}
306 
307 	/* Entitlement decreases */
308 	delta = vio_cmo.entitled - new_entitlement;
309 	avail = vio_cmo.excess.free;
310 
311 	/*
312 	 * Need to check how much unused entitlement each device can
313 	 * sacrifice to fulfill entitlement change.
314 	 */
315 	list_for_each_entry(dev_ent, &vio_cmo.device_list, list) {
316 		if (avail >= delta)
317 			break;
318 
319 		viodev = dev_ent->viodev;
320 		if ((viodev->cmo.entitled > viodev->cmo.allocated) &&
321 		    (viodev->cmo.entitled > VIO_CMO_MIN_ENT))
322 				avail += viodev->cmo.entitled -
323 				         max_t(size_t, viodev->cmo.allocated,
324 				               VIO_CMO_MIN_ENT);
325 	}
326 
327 	if (delta <= avail) {
328 		vio_cmo.entitled -= delta;
329 
330 		/* Take entitlement from the excess pool first */
331 		tmp = min(vio_cmo.excess.free, delta);
332 		vio_cmo.excess.size -= tmp;
333 		vio_cmo.excess.free -= tmp;
334 		delta -= tmp;
335 
336 		/*
337 		 * Remove all but VIO_CMO_MIN_ENT bytes from devices
338 		 * until entitlement change is served
339 		 */
340 		list_for_each_entry(dev_ent, &vio_cmo.device_list, list) {
341 			if (!delta)
342 				break;
343 
344 			viodev = dev_ent->viodev;
345 			tmp = 0;
346 			if ((viodev->cmo.entitled > viodev->cmo.allocated) &&
347 			    (viodev->cmo.entitled > VIO_CMO_MIN_ENT))
348 				tmp = viodev->cmo.entitled -
349 				      max_t(size_t, viodev->cmo.allocated,
350 				            VIO_CMO_MIN_ENT);
351 			viodev->cmo.entitled -= min(tmp, delta);
352 			delta -= min(tmp, delta);
353 		}
354 	} else {
355 		spin_unlock_irqrestore(&vio_cmo.lock, flags);
356 		return -ENOMEM;
357 	}
358 
359 out:
360 	schedule_delayed_work(&vio_cmo.balance_q, 0);
361 	spin_unlock_irqrestore(&vio_cmo.lock, flags);
362 	return 0;
363 }
364 
365 /**
366  * vio_cmo_balance - Balance entitlement among devices
367  *
368  * @work: work queue structure for this operation
369  *
370  * Any system entitlement above the minimum needed for devices, or
371  * already allocated to devices, can be distributed to the devices.
372  * The list of devices is iterated through to recalculate the desired
373  * entitlement level and to determine how much entitlement above the
374  * minimum entitlement is allocated to devices.
375  *
376  * Small chunks of the available entitlement are given to devices until
377  * their requirements are fulfilled or there is no entitlement left to give.
378  * Upon completion sizes of the reserve and excess pools are calculated.
379  *
380  * The system minimum entitlement level is also recalculated here.
381  * Entitlement will be reserved for devices even after vio_bus_remove to
382  * accommodate reloading the driver.  The OF tree is walked to count the
383  * number of devices present and this will remove entitlement for devices
384  * that have actually left the system after having vio_bus_remove called.
385  */
386 static void vio_cmo_balance(struct work_struct *work)
387 {
388 	struct vio_cmo *cmo;
389 	struct vio_dev *viodev;
390 	struct vio_cmo_dev_entry *dev_ent;
391 	unsigned long flags;
392 	size_t avail = 0, level, chunk, need;
393 	int devcount = 0, fulfilled;
394 
395 	cmo = container_of(work, struct vio_cmo, balance_q.work);
396 
397 	spin_lock_irqsave(&vio_cmo.lock, flags);
398 
399 	/* Calculate minimum entitlement and fulfill spare */
400 	cmo->min = vio_cmo_num_OF_devs() * VIO_CMO_MIN_ENT;
401 	BUG_ON(cmo->min > cmo->entitled);
402 	cmo->spare = min_t(size_t, VIO_CMO_MIN_ENT, (cmo->entitled - cmo->min));
403 	cmo->min += cmo->spare;
404 	cmo->desired = cmo->min;
405 
406 	/*
407 	 * Determine how much entitlement is available and reset device
408 	 * entitlements
409 	 */
410 	avail = cmo->entitled - cmo->spare;
411 	list_for_each_entry(dev_ent, &vio_cmo.device_list, list) {
412 		viodev = dev_ent->viodev;
413 		devcount++;
414 		viodev->cmo.entitled = VIO_CMO_MIN_ENT;
415 		cmo->desired += (viodev->cmo.desired - VIO_CMO_MIN_ENT);
416 		avail -= max_t(size_t, viodev->cmo.allocated, VIO_CMO_MIN_ENT);
417 	}
418 
419 	/*
420 	 * Having provided each device with the minimum entitlement, loop
421 	 * over the devices portioning out the remaining entitlement
422 	 * until there is nothing left.
423 	 */
424 	level = VIO_CMO_MIN_ENT;
425 	while (avail) {
426 		fulfilled = 0;
427 		list_for_each_entry(dev_ent, &vio_cmo.device_list, list) {
428 			viodev = dev_ent->viodev;
429 
430 			if (viodev->cmo.desired <= level) {
431 				fulfilled++;
432 				continue;
433 			}
434 
435 			/*
436 			 * Give the device up to VIO_CMO_BALANCE_CHUNK
437 			 * bytes of entitlement, but do not exceed the
438 			 * desired level of entitlement for the device.
439 			 */
440 			chunk = min_t(size_t, avail, VIO_CMO_BALANCE_CHUNK);
441 			chunk = min(chunk, (viodev->cmo.desired -
442 			                    viodev->cmo.entitled));
443 			viodev->cmo.entitled += chunk;
444 
445 			/*
446 			 * If the memory for this entitlement increase was
447 			 * already allocated to the device it does not come
448 			 * from the available pool being portioned out.
449 			 */
450 			need = max(viodev->cmo.allocated, viodev->cmo.entitled)-
451 			       max(viodev->cmo.allocated, level);
452 			avail -= need;
453 
454 		}
455 		if (fulfilled == devcount)
456 			break;
457 		level += VIO_CMO_BALANCE_CHUNK;
458 	}
459 
460 	/* Calculate new reserve and excess pool sizes */
461 	cmo->reserve.size = cmo->min;
462 	cmo->excess.free = 0;
463 	cmo->excess.size = 0;
464 	need = 0;
465 	list_for_each_entry(dev_ent, &vio_cmo.device_list, list) {
466 		viodev = dev_ent->viodev;
467 		/* Calculated reserve size above the minimum entitlement */
468 		if (viodev->cmo.entitled)
469 			cmo->reserve.size += (viodev->cmo.entitled -
470 			                      VIO_CMO_MIN_ENT);
471 		/* Calculated used excess entitlement */
472 		if (viodev->cmo.allocated > viodev->cmo.entitled)
473 			need += viodev->cmo.allocated - viodev->cmo.entitled;
474 	}
475 	cmo->excess.size = cmo->entitled - cmo->reserve.size;
476 	cmo->excess.free = cmo->excess.size - need;
477 
478 	cancel_delayed_work(to_delayed_work(work));
479 	spin_unlock_irqrestore(&vio_cmo.lock, flags);
480 }
481 
482 static void *vio_dma_iommu_alloc_coherent(struct device *dev, size_t size,
483 					  dma_addr_t *dma_handle, gfp_t flag,
484 					  unsigned long attrs)
485 {
486 	struct vio_dev *viodev = to_vio_dev(dev);
487 	void *ret;
488 
489 	if (vio_cmo_alloc(viodev, roundup(size, PAGE_SIZE))) {
490 		atomic_inc(&viodev->cmo.allocs_failed);
491 		return NULL;
492 	}
493 
494 	ret = iommu_alloc_coherent(dev, get_iommu_table_base(dev), size,
495 				    dma_handle, dev->coherent_dma_mask, flag,
496 				    dev_to_node(dev));
497 	if (unlikely(ret == NULL)) {
498 		vio_cmo_dealloc(viodev, roundup(size, PAGE_SIZE));
499 		atomic_inc(&viodev->cmo.allocs_failed);
500 	}
501 
502 	return ret;
503 }
504 
505 static void vio_dma_iommu_free_coherent(struct device *dev, size_t size,
506 					void *vaddr, dma_addr_t dma_handle,
507 					unsigned long attrs)
508 {
509 	struct vio_dev *viodev = to_vio_dev(dev);
510 
511 	iommu_free_coherent(get_iommu_table_base(dev), size, vaddr, dma_handle);
512 	vio_cmo_dealloc(viodev, roundup(size, PAGE_SIZE));
513 }
514 
515 static dma_addr_t vio_dma_iommu_map_page(struct device *dev, struct page *page,
516                                          unsigned long offset, size_t size,
517                                          enum dma_data_direction direction,
518                                          unsigned long attrs)
519 {
520 	struct vio_dev *viodev = to_vio_dev(dev);
521 	struct iommu_table *tbl = get_iommu_table_base(dev);
522 	dma_addr_t ret = DMA_MAPPING_ERROR;
523 
524 	if (vio_cmo_alloc(viodev, roundup(size, IOMMU_PAGE_SIZE(tbl))))
525 		goto out_fail;
526 	ret = iommu_map_page(dev, tbl, page, offset, size, dma_get_mask(dev),
527 			direction, attrs);
528 	if (unlikely(ret == DMA_MAPPING_ERROR))
529 		goto out_deallocate;
530 	return ret;
531 
532 out_deallocate:
533 	vio_cmo_dealloc(viodev, roundup(size, IOMMU_PAGE_SIZE(tbl)));
534 out_fail:
535 	atomic_inc(&viodev->cmo.allocs_failed);
536 	return DMA_MAPPING_ERROR;
537 }
538 
539 static void vio_dma_iommu_unmap_page(struct device *dev, dma_addr_t dma_handle,
540 				     size_t size,
541 				     enum dma_data_direction direction,
542 				     unsigned long attrs)
543 {
544 	struct vio_dev *viodev = to_vio_dev(dev);
545 	struct iommu_table *tbl = get_iommu_table_base(dev);
546 
547 	iommu_unmap_page(tbl, dma_handle, size, direction, attrs);
548 	vio_cmo_dealloc(viodev, roundup(size, IOMMU_PAGE_SIZE(tbl)));
549 }
550 
551 static int vio_dma_iommu_map_sg(struct device *dev, struct scatterlist *sglist,
552                                 int nelems, enum dma_data_direction direction,
553                                 unsigned long attrs)
554 {
555 	struct vio_dev *viodev = to_vio_dev(dev);
556 	struct iommu_table *tbl = get_iommu_table_base(dev);
557 	struct scatterlist *sgl;
558 	int ret, count;
559 	size_t alloc_size = 0;
560 
561 	for_each_sg(sglist, sgl, nelems, count)
562 		alloc_size += roundup(sgl->length, IOMMU_PAGE_SIZE(tbl));
563 
564 	ret = vio_cmo_alloc(viodev, alloc_size);
565 	if (ret)
566 		goto out_fail;
567 	ret = ppc_iommu_map_sg(dev, tbl, sglist, nelems, dma_get_mask(dev),
568 			direction, attrs);
569 	if (unlikely(!ret))
570 		goto out_deallocate;
571 
572 	for_each_sg(sglist, sgl, ret, count)
573 		alloc_size -= roundup(sgl->dma_length, IOMMU_PAGE_SIZE(tbl));
574 	if (alloc_size)
575 		vio_cmo_dealloc(viodev, alloc_size);
576 	return ret;
577 
578 out_deallocate:
579 	vio_cmo_dealloc(viodev, alloc_size);
580 out_fail:
581 	atomic_inc(&viodev->cmo.allocs_failed);
582 	return ret;
583 }
584 
585 static void vio_dma_iommu_unmap_sg(struct device *dev,
586 		struct scatterlist *sglist, int nelems,
587 		enum dma_data_direction direction,
588 		unsigned long attrs)
589 {
590 	struct vio_dev *viodev = to_vio_dev(dev);
591 	struct iommu_table *tbl = get_iommu_table_base(dev);
592 	struct scatterlist *sgl;
593 	size_t alloc_size = 0;
594 	int count;
595 
596 	for_each_sg(sglist, sgl, nelems, count)
597 		alloc_size += roundup(sgl->dma_length, IOMMU_PAGE_SIZE(tbl));
598 
599 	ppc_iommu_unmap_sg(tbl, sglist, nelems, direction, attrs);
600 	vio_cmo_dealloc(viodev, alloc_size);
601 }
602 
603 static const struct dma_map_ops vio_dma_mapping_ops = {
604 	.alloc             = vio_dma_iommu_alloc_coherent,
605 	.free              = vio_dma_iommu_free_coherent,
606 	.map_sg            = vio_dma_iommu_map_sg,
607 	.unmap_sg          = vio_dma_iommu_unmap_sg,
608 	.map_page          = vio_dma_iommu_map_page,
609 	.unmap_page        = vio_dma_iommu_unmap_page,
610 	.dma_supported     = dma_iommu_dma_supported,
611 	.get_required_mask = dma_iommu_get_required_mask,
612 	.mmap		   = dma_common_mmap,
613 	.get_sgtable	   = dma_common_get_sgtable,
614 	.alloc_pages	   = dma_common_alloc_pages,
615 	.free_pages	   = dma_common_free_pages,
616 };
617 
618 /**
619  * vio_cmo_set_dev_desired - Set desired entitlement for a device
620  *
621  * @viodev: struct vio_dev for device to alter
622  * @desired: new desired entitlement level in bytes
623  *
624  * For use by devices to request a change to their entitlement at runtime or
625  * through sysfs.  The desired entitlement level is changed and a balancing
626  * of system resources is scheduled to run in the future.
627  */
628 void vio_cmo_set_dev_desired(struct vio_dev *viodev, size_t desired)
629 {
630 	unsigned long flags;
631 	struct vio_cmo_dev_entry *dev_ent;
632 	int found = 0;
633 
634 	if (!firmware_has_feature(FW_FEATURE_CMO))
635 		return;
636 
637 	spin_lock_irqsave(&vio_cmo.lock, flags);
638 	if (desired < VIO_CMO_MIN_ENT)
639 		desired = VIO_CMO_MIN_ENT;
640 
641 	/*
642 	 * Changes will not be made for devices not in the device list.
643 	 * If it is not in the device list, then no driver is loaded
644 	 * for the device and it can not receive entitlement.
645 	 */
646 	list_for_each_entry(dev_ent, &vio_cmo.device_list, list)
647 		if (viodev == dev_ent->viodev) {
648 			found = 1;
649 			break;
650 		}
651 	if (!found) {
652 		spin_unlock_irqrestore(&vio_cmo.lock, flags);
653 		return;
654 	}
655 
656 	/* Increase/decrease in desired device entitlement */
657 	if (desired >= viodev->cmo.desired) {
658 		/* Just bump the bus and device values prior to a balance*/
659 		vio_cmo.desired += desired - viodev->cmo.desired;
660 		viodev->cmo.desired = desired;
661 	} else {
662 		/* Decrease bus and device values for desired entitlement */
663 		vio_cmo.desired -= viodev->cmo.desired - desired;
664 		viodev->cmo.desired = desired;
665 		/*
666 		 * If less entitlement is desired than current entitlement, move
667 		 * any reserve memory in the change region to the excess pool.
668 		 */
669 		if (viodev->cmo.entitled > desired) {
670 			vio_cmo.reserve.size -= viodev->cmo.entitled - desired;
671 			vio_cmo.excess.size += viodev->cmo.entitled - desired;
672 			/*
673 			 * If entitlement moving from the reserve pool to the
674 			 * excess pool is currently unused, add to the excess
675 			 * free counter.
676 			 */
677 			if (viodev->cmo.allocated < viodev->cmo.entitled)
678 				vio_cmo.excess.free += viodev->cmo.entitled -
679 				                       max(viodev->cmo.allocated, desired);
680 			viodev->cmo.entitled = desired;
681 		}
682 	}
683 	schedule_delayed_work(&vio_cmo.balance_q, 0);
684 	spin_unlock_irqrestore(&vio_cmo.lock, flags);
685 }
686 
687 /**
688  * vio_cmo_bus_probe - Handle CMO specific bus probe activities
689  *
690  * @viodev - Pointer to struct vio_dev for device
691  *
692  * Determine the devices IO memory entitlement needs, attempting
693  * to satisfy the system minimum entitlement at first and scheduling
694  * a balance operation to take care of the rest at a later time.
695  *
696  * Returns: 0 on success, -EINVAL when device doesn't support CMO, and
697  *          -ENOMEM when entitlement is not available for device or
698  *          device entry.
699  *
700  */
701 static int vio_cmo_bus_probe(struct vio_dev *viodev)
702 {
703 	struct vio_cmo_dev_entry *dev_ent;
704 	struct device *dev = &viodev->dev;
705 	struct iommu_table *tbl;
706 	struct vio_driver *viodrv = to_vio_driver(dev->driver);
707 	unsigned long flags;
708 	size_t size;
709 	bool dma_capable = false;
710 
711 	tbl = get_iommu_table_base(dev);
712 
713 	/* A device requires entitlement if it has a DMA window property */
714 	switch (viodev->family) {
715 	case VDEVICE:
716 		if (of_get_property(viodev->dev.of_node,
717 					"ibm,my-dma-window", NULL))
718 			dma_capable = true;
719 		break;
720 	case PFO:
721 		dma_capable = false;
722 		break;
723 	default:
724 		dev_warn(dev, "unknown device family: %d\n", viodev->family);
725 		BUG();
726 		break;
727 	}
728 
729 	/* Configure entitlement for the device. */
730 	if (dma_capable) {
731 		/* Check that the driver is CMO enabled and get desired DMA */
732 		if (!viodrv->get_desired_dma) {
733 			dev_err(dev, "%s: device driver does not support CMO\n",
734 			        __func__);
735 			return -EINVAL;
736 		}
737 
738 		viodev->cmo.desired =
739 			IOMMU_PAGE_ALIGN(viodrv->get_desired_dma(viodev), tbl);
740 		if (viodev->cmo.desired < VIO_CMO_MIN_ENT)
741 			viodev->cmo.desired = VIO_CMO_MIN_ENT;
742 		size = VIO_CMO_MIN_ENT;
743 
744 		dev_ent = kmalloc(sizeof(struct vio_cmo_dev_entry),
745 		                  GFP_KERNEL);
746 		if (!dev_ent)
747 			return -ENOMEM;
748 
749 		dev_ent->viodev = viodev;
750 		spin_lock_irqsave(&vio_cmo.lock, flags);
751 		list_add(&dev_ent->list, &vio_cmo.device_list);
752 	} else {
753 		viodev->cmo.desired = 0;
754 		size = 0;
755 		spin_lock_irqsave(&vio_cmo.lock, flags);
756 	}
757 
758 	/*
759 	 * If the needs for vio_cmo.min have not changed since they
760 	 * were last set, the number of devices in the OF tree has
761 	 * been constant and the IO memory for this is already in
762 	 * the reserve pool.
763 	 */
764 	if (vio_cmo.min == ((vio_cmo_num_OF_devs() + 1) *
765 	                    VIO_CMO_MIN_ENT)) {
766 		/* Updated desired entitlement if device requires it */
767 		if (size)
768 			vio_cmo.desired += (viodev->cmo.desired -
769 		                        VIO_CMO_MIN_ENT);
770 	} else {
771 		size_t tmp;
772 
773 		tmp = vio_cmo.spare + vio_cmo.excess.free;
774 		if (tmp < size) {
775 			dev_err(dev, "%s: insufficient free "
776 			        "entitlement to add device. "
777 			        "Need %lu, have %lu\n", __func__,
778 				size, (vio_cmo.spare + tmp));
779 			spin_unlock_irqrestore(&vio_cmo.lock, flags);
780 			return -ENOMEM;
781 		}
782 
783 		/* Use excess pool first to fulfill request */
784 		tmp = min(size, vio_cmo.excess.free);
785 		vio_cmo.excess.free -= tmp;
786 		vio_cmo.excess.size -= tmp;
787 		vio_cmo.reserve.size += tmp;
788 
789 		/* Use spare if excess pool was insufficient */
790 		vio_cmo.spare -= size - tmp;
791 
792 		/* Update bus accounting */
793 		vio_cmo.min += size;
794 		vio_cmo.desired += viodev->cmo.desired;
795 	}
796 	spin_unlock_irqrestore(&vio_cmo.lock, flags);
797 	return 0;
798 }
799 
800 /**
801  * vio_cmo_bus_remove - Handle CMO specific bus removal activities
802  *
803  * @viodev - Pointer to struct vio_dev for device
804  *
805  * Remove the device from the cmo device list.  The minimum entitlement
806  * will be reserved for the device as long as it is in the system.  The
807  * rest of the entitlement the device had been allocated will be returned
808  * to the system.
809  */
810 static void vio_cmo_bus_remove(struct vio_dev *viodev)
811 {
812 	struct vio_cmo_dev_entry *dev_ent;
813 	unsigned long flags;
814 	size_t tmp;
815 
816 	spin_lock_irqsave(&vio_cmo.lock, flags);
817 	if (viodev->cmo.allocated) {
818 		dev_err(&viodev->dev, "%s: device had %lu bytes of IO "
819 		        "allocated after remove operation.\n",
820 		        __func__, viodev->cmo.allocated);
821 		BUG();
822 	}
823 
824 	/*
825 	 * Remove the device from the device list being maintained for
826 	 * CMO enabled devices.
827 	 */
828 	list_for_each_entry(dev_ent, &vio_cmo.device_list, list)
829 		if (viodev == dev_ent->viodev) {
830 			list_del(&dev_ent->list);
831 			kfree(dev_ent);
832 			break;
833 		}
834 
835 	/*
836 	 * Devices may not require any entitlement and they do not need
837 	 * to be processed.  Otherwise, return the device's entitlement
838 	 * back to the pools.
839 	 */
840 	if (viodev->cmo.entitled) {
841 		/*
842 		 * This device has not yet left the OF tree, it's
843 		 * minimum entitlement remains in vio_cmo.min and
844 		 * vio_cmo.desired
845 		 */
846 		vio_cmo.desired -= (viodev->cmo.desired - VIO_CMO_MIN_ENT);
847 
848 		/*
849 		 * Save min allocation for device in reserve as long
850 		 * as it exists in OF tree as determined by later
851 		 * balance operation
852 		 */
853 		viodev->cmo.entitled -= VIO_CMO_MIN_ENT;
854 
855 		/* Replenish spare from freed reserve pool */
856 		if (viodev->cmo.entitled && (vio_cmo.spare < VIO_CMO_MIN_ENT)) {
857 			tmp = min(viodev->cmo.entitled, (VIO_CMO_MIN_ENT -
858 			                                 vio_cmo.spare));
859 			vio_cmo.spare += tmp;
860 			viodev->cmo.entitled -= tmp;
861 		}
862 
863 		/* Remaining reserve goes to excess pool */
864 		vio_cmo.excess.size += viodev->cmo.entitled;
865 		vio_cmo.excess.free += viodev->cmo.entitled;
866 		vio_cmo.reserve.size -= viodev->cmo.entitled;
867 
868 		/*
869 		 * Until the device is removed it will keep a
870 		 * minimum entitlement; this will guarantee that
871 		 * a module unload/load will result in a success.
872 		 */
873 		viodev->cmo.entitled = VIO_CMO_MIN_ENT;
874 		viodev->cmo.desired = VIO_CMO_MIN_ENT;
875 		atomic_set(&viodev->cmo.allocs_failed, 0);
876 	}
877 
878 	spin_unlock_irqrestore(&vio_cmo.lock, flags);
879 }
880 
881 static void vio_cmo_set_dma_ops(struct vio_dev *viodev)
882 {
883 	set_dma_ops(&viodev->dev, &vio_dma_mapping_ops);
884 }
885 
886 /**
887  * vio_cmo_bus_init - CMO entitlement initialization at bus init time
888  *
889  * Set up the reserve and excess entitlement pools based on available
890  * system entitlement and the number of devices in the OF tree that
891  * require entitlement in the reserve pool.
892  */
893 static void vio_cmo_bus_init(void)
894 {
895 	struct hvcall_mpp_data mpp_data;
896 	int err;
897 
898 	memset(&vio_cmo, 0, sizeof(struct vio_cmo));
899 	spin_lock_init(&vio_cmo.lock);
900 	INIT_LIST_HEAD(&vio_cmo.device_list);
901 	INIT_DELAYED_WORK(&vio_cmo.balance_q, vio_cmo_balance);
902 
903 	/* Get current system entitlement */
904 	err = h_get_mpp(&mpp_data);
905 
906 	/*
907 	 * On failure, continue with entitlement set to 0, will panic()
908 	 * later when spare is reserved.
909 	 */
910 	if (err != H_SUCCESS) {
911 		printk(KERN_ERR "%s: unable to determine system IO "\
912 		       "entitlement. (%d)\n", __func__, err);
913 		vio_cmo.entitled = 0;
914 	} else {
915 		vio_cmo.entitled = mpp_data.entitled_mem;
916 	}
917 
918 	/* Set reservation and check against entitlement */
919 	vio_cmo.spare = VIO_CMO_MIN_ENT;
920 	vio_cmo.reserve.size = vio_cmo.spare;
921 	vio_cmo.reserve.size += (vio_cmo_num_OF_devs() *
922 	                         VIO_CMO_MIN_ENT);
923 	if (vio_cmo.reserve.size > vio_cmo.entitled) {
924 		printk(KERN_ERR "%s: insufficient system entitlement\n",
925 		       __func__);
926 		panic("%s: Insufficient system entitlement", __func__);
927 	}
928 
929 	/* Set the remaining accounting variables */
930 	vio_cmo.excess.size = vio_cmo.entitled - vio_cmo.reserve.size;
931 	vio_cmo.excess.free = vio_cmo.excess.size;
932 	vio_cmo.min = vio_cmo.reserve.size;
933 	vio_cmo.desired = vio_cmo.reserve.size;
934 }
935 
936 /* sysfs device functions and data structures for CMO */
937 
938 #define viodev_cmo_rd_attr(name)                                        \
939 static ssize_t cmo_##name##_show(struct device *dev,                    \
940                                         struct device_attribute *attr,  \
941                                          char *buf)                     \
942 {                                                                       \
943 	return sprintf(buf, "%lu\n", to_vio_dev(dev)->cmo.name);        \
944 }
945 
946 static ssize_t cmo_allocs_failed_show(struct device *dev,
947 		struct device_attribute *attr, char *buf)
948 {
949 	struct vio_dev *viodev = to_vio_dev(dev);
950 	return sprintf(buf, "%d\n", atomic_read(&viodev->cmo.allocs_failed));
951 }
952 
953 static ssize_t cmo_allocs_failed_store(struct device *dev,
954 		struct device_attribute *attr, const char *buf, size_t count)
955 {
956 	struct vio_dev *viodev = to_vio_dev(dev);
957 	atomic_set(&viodev->cmo.allocs_failed, 0);
958 	return count;
959 }
960 
961 static ssize_t cmo_desired_store(struct device *dev,
962 		struct device_attribute *attr, const char *buf, size_t count)
963 {
964 	struct vio_dev *viodev = to_vio_dev(dev);
965 	size_t new_desired;
966 	int ret;
967 
968 	ret = kstrtoul(buf, 10, &new_desired);
969 	if (ret)
970 		return ret;
971 
972 	vio_cmo_set_dev_desired(viodev, new_desired);
973 	return count;
974 }
975 
976 viodev_cmo_rd_attr(desired);
977 viodev_cmo_rd_attr(entitled);
978 viodev_cmo_rd_attr(allocated);
979 
980 static ssize_t name_show(struct device *, struct device_attribute *, char *);
981 static ssize_t devspec_show(struct device *, struct device_attribute *, char *);
982 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
983 			     char *buf);
984 
985 static struct device_attribute dev_attr_name;
986 static struct device_attribute dev_attr_devspec;
987 static struct device_attribute dev_attr_modalias;
988 
989 static DEVICE_ATTR_RO(cmo_entitled);
990 static DEVICE_ATTR_RO(cmo_allocated);
991 static DEVICE_ATTR_RW(cmo_desired);
992 static DEVICE_ATTR_RW(cmo_allocs_failed);
993 
994 static struct attribute *vio_cmo_dev_attrs[] = {
995 	&dev_attr_name.attr,
996 	&dev_attr_devspec.attr,
997 	&dev_attr_modalias.attr,
998 	&dev_attr_cmo_entitled.attr,
999 	&dev_attr_cmo_allocated.attr,
1000 	&dev_attr_cmo_desired.attr,
1001 	&dev_attr_cmo_allocs_failed.attr,
1002 	NULL,
1003 };
1004 ATTRIBUTE_GROUPS(vio_cmo_dev);
1005 
1006 /* sysfs bus functions and data structures for CMO */
1007 
1008 #define viobus_cmo_rd_attr(name)                                        \
1009 static ssize_t cmo_bus_##name##_show(struct bus_type *bt, char *buf)    \
1010 {                                                                       \
1011 	return sprintf(buf, "%lu\n", vio_cmo.name);                     \
1012 }                                                                       \
1013 static struct bus_attribute bus_attr_cmo_bus_##name =			\
1014 	__ATTR(cmo_##name, S_IRUGO, cmo_bus_##name##_show, NULL)
1015 
1016 #define viobus_cmo_pool_rd_attr(name, var)                              \
1017 static ssize_t                                                          \
1018 cmo_##name##_##var##_show(struct bus_type *bt, char *buf)               \
1019 {                                                                       \
1020 	return sprintf(buf, "%lu\n", vio_cmo.name.var);                 \
1021 }                                                                       \
1022 static BUS_ATTR_RO(cmo_##name##_##var)
1023 
1024 viobus_cmo_rd_attr(entitled);
1025 viobus_cmo_rd_attr(spare);
1026 viobus_cmo_rd_attr(min);
1027 viobus_cmo_rd_attr(desired);
1028 viobus_cmo_rd_attr(curr);
1029 viobus_cmo_pool_rd_attr(reserve, size);
1030 viobus_cmo_pool_rd_attr(excess, size);
1031 viobus_cmo_pool_rd_attr(excess, free);
1032 
1033 static ssize_t cmo_high_show(struct bus_type *bt, char *buf)
1034 {
1035 	return sprintf(buf, "%lu\n", vio_cmo.high);
1036 }
1037 
1038 static ssize_t cmo_high_store(struct bus_type *bt, const char *buf,
1039 			      size_t count)
1040 {
1041 	unsigned long flags;
1042 
1043 	spin_lock_irqsave(&vio_cmo.lock, flags);
1044 	vio_cmo.high = vio_cmo.curr;
1045 	spin_unlock_irqrestore(&vio_cmo.lock, flags);
1046 
1047 	return count;
1048 }
1049 static BUS_ATTR_RW(cmo_high);
1050 
1051 static struct attribute *vio_bus_attrs[] = {
1052 	&bus_attr_cmo_bus_entitled.attr,
1053 	&bus_attr_cmo_bus_spare.attr,
1054 	&bus_attr_cmo_bus_min.attr,
1055 	&bus_attr_cmo_bus_desired.attr,
1056 	&bus_attr_cmo_bus_curr.attr,
1057 	&bus_attr_cmo_high.attr,
1058 	&bus_attr_cmo_reserve_size.attr,
1059 	&bus_attr_cmo_excess_size.attr,
1060 	&bus_attr_cmo_excess_free.attr,
1061 	NULL,
1062 };
1063 ATTRIBUTE_GROUPS(vio_bus);
1064 
1065 static void __init vio_cmo_sysfs_init(void)
1066 {
1067 	vio_bus_type.dev_groups = vio_cmo_dev_groups;
1068 	vio_bus_type.bus_groups = vio_bus_groups;
1069 }
1070 #else /* CONFIG_PPC_SMLPAR */
1071 int vio_cmo_entitlement_update(size_t new_entitlement) { return 0; }
1072 void vio_cmo_set_dev_desired(struct vio_dev *viodev, size_t desired) {}
1073 static int vio_cmo_bus_probe(struct vio_dev *viodev) { return 0; }
1074 static void vio_cmo_bus_remove(struct vio_dev *viodev) {}
1075 static void vio_cmo_set_dma_ops(struct vio_dev *viodev) {}
1076 static void vio_cmo_bus_init(void) {}
1077 static void __init vio_cmo_sysfs_init(void) { }
1078 #endif /* CONFIG_PPC_SMLPAR */
1079 EXPORT_SYMBOL(vio_cmo_entitlement_update);
1080 EXPORT_SYMBOL(vio_cmo_set_dev_desired);
1081 
1082 
1083 /*
1084  * Platform Facilities Option (PFO) support
1085  */
1086 
1087 /**
1088  * vio_h_cop_sync - Perform a synchronous PFO co-processor operation
1089  *
1090  * @vdev - Pointer to a struct vio_dev for device
1091  * @op - Pointer to a struct vio_pfo_op for the operation parameters
1092  *
1093  * Calls the hypervisor to synchronously perform the PFO operation
1094  * described in @op.  In the case of a busy response from the hypervisor,
1095  * the operation will be re-submitted indefinitely unless a non-zero timeout
1096  * is specified or an error occurs. The timeout places a limit on when to
1097  * stop re-submitting a operation, the total time can be exceeded if an
1098  * operation is in progress.
1099  *
1100  * If op->hcall_ret is not NULL, this will be set to the return from the
1101  * last h_cop_op call or it will be 0 if an error not involving the h_call
1102  * was encountered.
1103  *
1104  * Returns:
1105  *	0 on success,
1106  *	-EINVAL if the h_call fails due to an invalid parameter,
1107  *	-E2BIG if the h_call can not be performed synchronously,
1108  *	-EBUSY if a timeout is specified and has elapsed,
1109  *	-EACCES if the memory area for data/status has been rescinded, or
1110  *	-EPERM if a hardware fault has been indicated
1111  */
1112 int vio_h_cop_sync(struct vio_dev *vdev, struct vio_pfo_op *op)
1113 {
1114 	struct device *dev = &vdev->dev;
1115 	unsigned long deadline = 0;
1116 	long hret = 0;
1117 	int ret = 0;
1118 
1119 	if (op->timeout)
1120 		deadline = jiffies + msecs_to_jiffies(op->timeout);
1121 
1122 	while (true) {
1123 		hret = plpar_hcall_norets(H_COP, op->flags,
1124 				vdev->resource_id,
1125 				op->in, op->inlen, op->out,
1126 				op->outlen, op->csbcpb);
1127 
1128 		if (hret == H_SUCCESS ||
1129 		    (hret != H_NOT_ENOUGH_RESOURCES &&
1130 		     hret != H_BUSY && hret != H_RESOURCE) ||
1131 		    (op->timeout && time_after(deadline, jiffies)))
1132 			break;
1133 
1134 		dev_dbg(dev, "%s: hcall ret(%ld), retrying.\n", __func__, hret);
1135 	}
1136 
1137 	switch (hret) {
1138 	case H_SUCCESS:
1139 		ret = 0;
1140 		break;
1141 	case H_OP_MODE:
1142 	case H_TOO_BIG:
1143 		ret = -E2BIG;
1144 		break;
1145 	case H_RESCINDED:
1146 		ret = -EACCES;
1147 		break;
1148 	case H_HARDWARE:
1149 		ret = -EPERM;
1150 		break;
1151 	case H_NOT_ENOUGH_RESOURCES:
1152 	case H_RESOURCE:
1153 	case H_BUSY:
1154 		ret = -EBUSY;
1155 		break;
1156 	default:
1157 		ret = -EINVAL;
1158 		break;
1159 	}
1160 
1161 	if (ret)
1162 		dev_dbg(dev, "%s: Sync h_cop_op failure (ret:%d) (hret:%ld)\n",
1163 				__func__, ret, hret);
1164 
1165 	op->hcall_err = hret;
1166 	return ret;
1167 }
1168 EXPORT_SYMBOL(vio_h_cop_sync);
1169 
1170 static struct iommu_table *vio_build_iommu_table(struct vio_dev *dev)
1171 {
1172 	const __be32 *dma_window;
1173 	struct iommu_table *tbl;
1174 	unsigned long offset, size;
1175 
1176 	dma_window = of_get_property(dev->dev.of_node,
1177 				  "ibm,my-dma-window", NULL);
1178 	if (!dma_window)
1179 		return NULL;
1180 
1181 	tbl = kzalloc(sizeof(*tbl), GFP_KERNEL);
1182 	if (tbl == NULL)
1183 		return NULL;
1184 
1185 	kref_init(&tbl->it_kref);
1186 
1187 	of_parse_dma_window(dev->dev.of_node, dma_window,
1188 			    &tbl->it_index, &offset, &size);
1189 
1190 	/* TCE table size - measured in tce entries */
1191 	tbl->it_page_shift = IOMMU_PAGE_SHIFT_4K;
1192 	tbl->it_size = size >> tbl->it_page_shift;
1193 	/* offset for VIO should always be 0 */
1194 	tbl->it_offset = offset >> tbl->it_page_shift;
1195 	tbl->it_busno = 0;
1196 	tbl->it_type = TCE_VB;
1197 	tbl->it_blocksize = 16;
1198 
1199 	if (firmware_has_feature(FW_FEATURE_LPAR))
1200 		tbl->it_ops = &iommu_table_lpar_multi_ops;
1201 	else
1202 		tbl->it_ops = &iommu_table_pseries_ops;
1203 
1204 	return iommu_init_table(tbl, -1, 0, 0);
1205 }
1206 
1207 /**
1208  * vio_match_device: - Tell if a VIO device has a matching
1209  *			VIO device id structure.
1210  * @ids:	array of VIO device id structures to search in
1211  * @dev:	the VIO device structure to match against
1212  *
1213  * Used by a driver to check whether a VIO device present in the
1214  * system is in its list of supported devices. Returns the matching
1215  * vio_device_id structure or NULL if there is no match.
1216  */
1217 static const struct vio_device_id *vio_match_device(
1218 		const struct vio_device_id *ids, const struct vio_dev *dev)
1219 {
1220 	while (ids->type[0] != '\0') {
1221 		if ((strncmp(dev->type, ids->type, strlen(ids->type)) == 0) &&
1222 		    of_device_is_compatible(dev->dev.of_node,
1223 					 ids->compat))
1224 			return ids;
1225 		ids++;
1226 	}
1227 	return NULL;
1228 }
1229 
1230 /*
1231  * Convert from struct device to struct vio_dev and pass to driver.
1232  * dev->driver has already been set by generic code because vio_bus_match
1233  * succeeded.
1234  */
1235 static int vio_bus_probe(struct device *dev)
1236 {
1237 	struct vio_dev *viodev = to_vio_dev(dev);
1238 	struct vio_driver *viodrv = to_vio_driver(dev->driver);
1239 	const struct vio_device_id *id;
1240 	int error = -ENODEV;
1241 
1242 	if (!viodrv->probe)
1243 		return error;
1244 
1245 	id = vio_match_device(viodrv->id_table, viodev);
1246 	if (id) {
1247 		memset(&viodev->cmo, 0, sizeof(viodev->cmo));
1248 		if (firmware_has_feature(FW_FEATURE_CMO)) {
1249 			error = vio_cmo_bus_probe(viodev);
1250 			if (error)
1251 				return error;
1252 		}
1253 		error = viodrv->probe(viodev, id);
1254 		if (error && firmware_has_feature(FW_FEATURE_CMO))
1255 			vio_cmo_bus_remove(viodev);
1256 	}
1257 
1258 	return error;
1259 }
1260 
1261 /* convert from struct device to struct vio_dev and pass to driver. */
1262 static void vio_bus_remove(struct device *dev)
1263 {
1264 	struct vio_dev *viodev = to_vio_dev(dev);
1265 	struct vio_driver *viodrv = to_vio_driver(dev->driver);
1266 	struct device *devptr;
1267 
1268 	/*
1269 	 * Hold a reference to the device after the remove function is called
1270 	 * to allow for CMO accounting cleanup for the device.
1271 	 */
1272 	devptr = get_device(dev);
1273 
1274 	if (viodrv->remove)
1275 		viodrv->remove(viodev);
1276 
1277 	if (firmware_has_feature(FW_FEATURE_CMO))
1278 		vio_cmo_bus_remove(viodev);
1279 
1280 	put_device(devptr);
1281 }
1282 
1283 static void vio_bus_shutdown(struct device *dev)
1284 {
1285 	struct vio_dev *viodev = to_vio_dev(dev);
1286 	struct vio_driver *viodrv;
1287 
1288 	if (dev->driver) {
1289 		viodrv = to_vio_driver(dev->driver);
1290 		if (viodrv->shutdown)
1291 			viodrv->shutdown(viodev);
1292 		else if (kexec_in_progress)
1293 			vio_bus_remove(dev);
1294 	}
1295 }
1296 
1297 /**
1298  * vio_register_driver: - Register a new vio driver
1299  * @viodrv:	The vio_driver structure to be registered.
1300  */
1301 int __vio_register_driver(struct vio_driver *viodrv, struct module *owner,
1302 			  const char *mod_name)
1303 {
1304 	// vio_bus_type is only initialised for pseries
1305 	if (!machine_is(pseries))
1306 		return -ENODEV;
1307 
1308 	pr_debug("%s: driver %s registering\n", __func__, viodrv->name);
1309 
1310 	/* fill in 'struct driver' fields */
1311 	viodrv->driver.name = viodrv->name;
1312 	viodrv->driver.pm = viodrv->pm;
1313 	viodrv->driver.bus = &vio_bus_type;
1314 	viodrv->driver.owner = owner;
1315 	viodrv->driver.mod_name = mod_name;
1316 
1317 	return driver_register(&viodrv->driver);
1318 }
1319 EXPORT_SYMBOL(__vio_register_driver);
1320 
1321 /**
1322  * vio_unregister_driver - Remove registration of vio driver.
1323  * @viodrv:	The vio_driver struct to be removed form registration
1324  */
1325 void vio_unregister_driver(struct vio_driver *viodrv)
1326 {
1327 	driver_unregister(&viodrv->driver);
1328 }
1329 EXPORT_SYMBOL(vio_unregister_driver);
1330 
1331 /* vio_dev refcount hit 0 */
1332 static void vio_dev_release(struct device *dev)
1333 {
1334 	struct iommu_table *tbl = get_iommu_table_base(dev);
1335 
1336 	if (tbl)
1337 		iommu_tce_table_put(tbl);
1338 	of_node_put(dev->of_node);
1339 	kfree(to_vio_dev(dev));
1340 }
1341 
1342 /**
1343  * vio_register_device_node: - Register a new vio device.
1344  * @of_node:	The OF node for this device.
1345  *
1346  * Creates and initializes a vio_dev structure from the data in
1347  * of_node and adds it to the list of virtual devices.
1348  * Returns a pointer to the created vio_dev or NULL if node has
1349  * NULL device_type or compatible fields.
1350  */
1351 struct vio_dev *vio_register_device_node(struct device_node *of_node)
1352 {
1353 	struct vio_dev *viodev;
1354 	struct device_node *parent_node;
1355 	const __be32 *prop;
1356 	enum vio_dev_family family;
1357 
1358 	/*
1359 	 * Determine if this node is a under the /vdevice node or under the
1360 	 * /ibm,platform-facilities node.  This decides the device's family.
1361 	 */
1362 	parent_node = of_get_parent(of_node);
1363 	if (parent_node) {
1364 		if (of_node_is_type(parent_node, "ibm,platform-facilities"))
1365 			family = PFO;
1366 		else if (of_node_is_type(parent_node, "vdevice"))
1367 			family = VDEVICE;
1368 		else {
1369 			pr_warn("%s: parent(%pOF) of %pOFn not recognized.\n",
1370 					__func__,
1371 					parent_node,
1372 					of_node);
1373 			of_node_put(parent_node);
1374 			return NULL;
1375 		}
1376 		of_node_put(parent_node);
1377 	} else {
1378 		pr_warn("%s: could not determine the parent of node %pOFn.\n",
1379 				__func__, of_node);
1380 		return NULL;
1381 	}
1382 
1383 	if (family == PFO) {
1384 		if (of_get_property(of_node, "interrupt-controller", NULL)) {
1385 			pr_debug("%s: Skipping the interrupt controller %pOFn.\n",
1386 					__func__, of_node);
1387 			return NULL;
1388 		}
1389 	}
1390 
1391 	/* allocate a vio_dev for this node */
1392 	viodev = kzalloc(sizeof(struct vio_dev), GFP_KERNEL);
1393 	if (viodev == NULL) {
1394 		pr_warn("%s: allocation failure for VIO device.\n", __func__);
1395 		return NULL;
1396 	}
1397 
1398 	/* we need the 'device_type' property, in order to match with drivers */
1399 	viodev->family = family;
1400 	if (viodev->family == VDEVICE) {
1401 		unsigned int unit_address;
1402 
1403 		viodev->type = of_node_get_device_type(of_node);
1404 		if (!viodev->type) {
1405 			pr_warn("%s: node %pOFn is missing the 'device_type' "
1406 					"property.\n", __func__, of_node);
1407 			goto out;
1408 		}
1409 
1410 		prop = of_get_property(of_node, "reg", NULL);
1411 		if (prop == NULL) {
1412 			pr_warn("%s: node %pOFn missing 'reg'\n",
1413 					__func__, of_node);
1414 			goto out;
1415 		}
1416 		unit_address = of_read_number(prop, 1);
1417 		dev_set_name(&viodev->dev, "%x", unit_address);
1418 		viodev->irq = irq_of_parse_and_map(of_node, 0);
1419 		viodev->unit_address = unit_address;
1420 	} else {
1421 		/* PFO devices need their resource_id for submitting COP_OPs
1422 		 * This is an optional field for devices, but is required when
1423 		 * performing synchronous ops */
1424 		prop = of_get_property(of_node, "ibm,resource-id", NULL);
1425 		if (prop != NULL)
1426 			viodev->resource_id = of_read_number(prop, 1);
1427 
1428 		dev_set_name(&viodev->dev, "%pOFn", of_node);
1429 		viodev->type = dev_name(&viodev->dev);
1430 		viodev->irq = 0;
1431 	}
1432 
1433 	viodev->name = of_node->name;
1434 	viodev->dev.of_node = of_node_get(of_node);
1435 
1436 	set_dev_node(&viodev->dev, of_node_to_nid(of_node));
1437 
1438 	/* init generic 'struct device' fields: */
1439 	viodev->dev.parent = &vio_bus_device.dev;
1440 	viodev->dev.bus = &vio_bus_type;
1441 	viodev->dev.release = vio_dev_release;
1442 
1443 	if (of_get_property(viodev->dev.of_node, "ibm,my-dma-window", NULL)) {
1444 		if (firmware_has_feature(FW_FEATURE_CMO))
1445 			vio_cmo_set_dma_ops(viodev);
1446 		else
1447 			set_dma_ops(&viodev->dev, &dma_iommu_ops);
1448 
1449 		set_iommu_table_base(&viodev->dev,
1450 				     vio_build_iommu_table(viodev));
1451 
1452 		/* needed to ensure proper operation of coherent allocations
1453 		 * later, in case driver doesn't set it explicitly */
1454 		viodev->dev.coherent_dma_mask = DMA_BIT_MASK(64);
1455 		viodev->dev.dma_mask = &viodev->dev.coherent_dma_mask;
1456 	}
1457 
1458 	/* register with generic device framework */
1459 	if (device_register(&viodev->dev)) {
1460 		printk(KERN_ERR "%s: failed to register device %s\n",
1461 				__func__, dev_name(&viodev->dev));
1462 		put_device(&viodev->dev);
1463 		return NULL;
1464 	}
1465 
1466 	return viodev;
1467 
1468 out:	/* Use this exit point for any return prior to device_register */
1469 	kfree(viodev);
1470 
1471 	return NULL;
1472 }
1473 EXPORT_SYMBOL(vio_register_device_node);
1474 
1475 /*
1476  * vio_bus_scan_for_devices - Scan OF and register each child device
1477  * @root_name - OF node name for the root of the subtree to search.
1478  *		This must be non-NULL
1479  *
1480  * Starting from the root node provide, register the device node for
1481  * each child beneath the root.
1482  */
1483 static void __init vio_bus_scan_register_devices(char *root_name)
1484 {
1485 	struct device_node *node_root, *node_child;
1486 
1487 	if (!root_name)
1488 		return;
1489 
1490 	node_root = of_find_node_by_name(NULL, root_name);
1491 	if (node_root) {
1492 
1493 		/*
1494 		 * Create struct vio_devices for each virtual device in
1495 		 * the device tree. Drivers will associate with them later.
1496 		 */
1497 		node_child = of_get_next_child(node_root, NULL);
1498 		while (node_child) {
1499 			vio_register_device_node(node_child);
1500 			node_child = of_get_next_child(node_root, node_child);
1501 		}
1502 		of_node_put(node_root);
1503 	}
1504 }
1505 
1506 /**
1507  * vio_bus_init: - Initialize the virtual IO bus
1508  */
1509 static int __init vio_bus_init(void)
1510 {
1511 	int err;
1512 
1513 	if (firmware_has_feature(FW_FEATURE_CMO))
1514 		vio_cmo_sysfs_init();
1515 
1516 	err = bus_register(&vio_bus_type);
1517 	if (err) {
1518 		printk(KERN_ERR "failed to register VIO bus\n");
1519 		return err;
1520 	}
1521 
1522 	/*
1523 	 * The fake parent of all vio devices, just to give us
1524 	 * a nice directory
1525 	 */
1526 	err = device_register(&vio_bus_device.dev);
1527 	if (err) {
1528 		printk(KERN_WARNING "%s: device_register returned %i\n",
1529 				__func__, err);
1530 		return err;
1531 	}
1532 
1533 	if (firmware_has_feature(FW_FEATURE_CMO))
1534 		vio_cmo_bus_init();
1535 
1536 	return 0;
1537 }
1538 machine_postcore_initcall(pseries, vio_bus_init);
1539 
1540 static int __init vio_device_init(void)
1541 {
1542 	vio_bus_scan_register_devices("vdevice");
1543 	vio_bus_scan_register_devices("ibm,platform-facilities");
1544 
1545 	return 0;
1546 }
1547 machine_device_initcall(pseries, vio_device_init);
1548 
1549 static ssize_t name_show(struct device *dev,
1550 		struct device_attribute *attr, char *buf)
1551 {
1552 	return sprintf(buf, "%s\n", to_vio_dev(dev)->name);
1553 }
1554 static DEVICE_ATTR_RO(name);
1555 
1556 static ssize_t devspec_show(struct device *dev,
1557 		struct device_attribute *attr, char *buf)
1558 {
1559 	struct device_node *of_node = dev->of_node;
1560 
1561 	return sprintf(buf, "%pOF\n", of_node);
1562 }
1563 static DEVICE_ATTR_RO(devspec);
1564 
1565 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
1566 			     char *buf)
1567 {
1568 	const struct vio_dev *vio_dev = to_vio_dev(dev);
1569 	struct device_node *dn;
1570 	const char *cp;
1571 
1572 	dn = dev->of_node;
1573 	if (!dn) {
1574 		strcpy(buf, "\n");
1575 		return strlen(buf);
1576 	}
1577 	cp = of_get_property(dn, "compatible", NULL);
1578 	if (!cp) {
1579 		strcpy(buf, "\n");
1580 		return strlen(buf);
1581 	}
1582 
1583 	return sprintf(buf, "vio:T%sS%s\n", vio_dev->type, cp);
1584 }
1585 static DEVICE_ATTR_RO(modalias);
1586 
1587 static struct attribute *vio_dev_attrs[] = {
1588 	&dev_attr_name.attr,
1589 	&dev_attr_devspec.attr,
1590 	&dev_attr_modalias.attr,
1591 	NULL,
1592 };
1593 ATTRIBUTE_GROUPS(vio_dev);
1594 
1595 void vio_unregister_device(struct vio_dev *viodev)
1596 {
1597 	device_unregister(&viodev->dev);
1598 	if (viodev->family == VDEVICE)
1599 		irq_dispose_mapping(viodev->irq);
1600 }
1601 EXPORT_SYMBOL(vio_unregister_device);
1602 
1603 static int vio_bus_match(struct device *dev, struct device_driver *drv)
1604 {
1605 	const struct vio_dev *vio_dev = to_vio_dev(dev);
1606 	struct vio_driver *vio_drv = to_vio_driver(drv);
1607 	const struct vio_device_id *ids = vio_drv->id_table;
1608 
1609 	return (ids != NULL) && (vio_match_device(ids, vio_dev) != NULL);
1610 }
1611 
1612 static int vio_hotplug(const struct device *dev, struct kobj_uevent_env *env)
1613 {
1614 	const struct vio_dev *vio_dev = to_vio_dev(dev);
1615 	const struct device_node *dn;
1616 	const char *cp;
1617 
1618 	dn = dev->of_node;
1619 	if (!dn)
1620 		return -ENODEV;
1621 	cp = of_get_property(dn, "compatible", NULL);
1622 	if (!cp)
1623 		return -ENODEV;
1624 
1625 	add_uevent_var(env, "MODALIAS=vio:T%sS%s", vio_dev->type, cp);
1626 	return 0;
1627 }
1628 
1629 struct bus_type vio_bus_type = {
1630 	.name = "vio",
1631 	.dev_groups = vio_dev_groups,
1632 	.uevent = vio_hotplug,
1633 	.match = vio_bus_match,
1634 	.probe = vio_bus_probe,
1635 	.remove = vio_bus_remove,
1636 	.shutdown = vio_bus_shutdown,
1637 };
1638 
1639 /**
1640  * vio_get_attribute: - get attribute for virtual device
1641  * @vdev:	The vio device to get property.
1642  * @which:	The property/attribute to be extracted.
1643  * @length:	Pointer to length of returned data size (unused if NULL).
1644  *
1645  * Calls prom.c's of_get_property() to return the value of the
1646  * attribute specified by @which
1647 */
1648 const void *vio_get_attribute(struct vio_dev *vdev, char *which, int *length)
1649 {
1650 	return of_get_property(vdev->dev.of_node, which, length);
1651 }
1652 EXPORT_SYMBOL(vio_get_attribute);
1653 
1654 /* vio_find_name() - internal because only vio.c knows how we formatted the
1655  * kobject name
1656  */
1657 static struct vio_dev *vio_find_name(const char *name)
1658 {
1659 	struct device *found;
1660 
1661 	found = bus_find_device_by_name(&vio_bus_type, NULL, name);
1662 	if (!found)
1663 		return NULL;
1664 
1665 	return to_vio_dev(found);
1666 }
1667 
1668 /**
1669  * vio_find_node - find an already-registered vio_dev
1670  * @vnode: device_node of the virtual device we're looking for
1671  *
1672  * Takes a reference to the embedded struct device which needs to be dropped
1673  * after use.
1674  */
1675 struct vio_dev *vio_find_node(struct device_node *vnode)
1676 {
1677 	char kobj_name[20];
1678 	struct device_node *vnode_parent;
1679 
1680 	vnode_parent = of_get_parent(vnode);
1681 	if (!vnode_parent)
1682 		return NULL;
1683 
1684 	/* construct the kobject name from the device node */
1685 	if (of_node_is_type(vnode_parent, "vdevice")) {
1686 		const __be32 *prop;
1687 
1688 		prop = of_get_property(vnode, "reg", NULL);
1689 		if (!prop)
1690 			goto out;
1691 		snprintf(kobj_name, sizeof(kobj_name), "%x",
1692 			 (uint32_t)of_read_number(prop, 1));
1693 	} else if (of_node_is_type(vnode_parent, "ibm,platform-facilities"))
1694 		snprintf(kobj_name, sizeof(kobj_name), "%pOFn", vnode);
1695 	else
1696 		goto out;
1697 
1698 	of_node_put(vnode_parent);
1699 	return vio_find_name(kobj_name);
1700 out:
1701 	of_node_put(vnode_parent);
1702 	return NULL;
1703 }
1704 EXPORT_SYMBOL(vio_find_node);
1705 
1706 int vio_enable_interrupts(struct vio_dev *dev)
1707 {
1708 	int rc = h_vio_signal(dev->unit_address, VIO_IRQ_ENABLE);
1709 	if (rc != H_SUCCESS)
1710 		printk(KERN_ERR "vio: Error 0x%x enabling interrupts\n", rc);
1711 	return rc;
1712 }
1713 EXPORT_SYMBOL(vio_enable_interrupts);
1714 
1715 int vio_disable_interrupts(struct vio_dev *dev)
1716 {
1717 	int rc = h_vio_signal(dev->unit_address, VIO_IRQ_DISABLE);
1718 	if (rc != H_SUCCESS)
1719 		printk(KERN_ERR "vio: Error 0x%x disabling interrupts\n", rc);
1720 	return rc;
1721 }
1722 EXPORT_SYMBOL(vio_disable_interrupts);
1723 
1724 static int __init vio_init(void)
1725 {
1726 	dma_debug_add_bus(&vio_bus_type);
1727 	return 0;
1728 }
1729 machine_fs_initcall(pseries, vio_init);
1730