1/*
  2 * Copyright IBM Corp. 2012
  3 *
  4 * Author(s):
  5 *   Jan Glauber <jang@linux.vnet.ibm.com>
  6 */
  7
  8#include <linux/kernel.h>
  9#include <linux/slab.h>
 10#include <linux/export.h>
 11#include <linux/iommu-helper.h>
 12#include <linux/dma-mapping.h>
 13#include <linux/vmalloc.h>
 14#include <linux/pci.h>
 15#include <asm/pci_dma.h>
 16
 17static struct kmem_cache *dma_region_table_cache;
 18static struct kmem_cache *dma_page_table_cache;
 19
 20static unsigned long *dma_alloc_cpu_table(void)
 21{
 22	unsigned long *table, *entry;
 23
 24	table = kmem_cache_alloc(dma_region_table_cache, GFP_ATOMIC);
 25	if (!table)
 26		return NULL;
 27
 28	for (entry = table; entry < table + ZPCI_TABLE_ENTRIES; entry++)
 29		*entry = ZPCI_TABLE_INVALID | ZPCI_TABLE_PROTECTED;
 30	return table;
 31}
 32
 33static void dma_free_cpu_table(void *table)
 34{
 35	kmem_cache_free(dma_region_table_cache, table);
 36}
 37
 38static unsigned long *dma_alloc_page_table(void)
 39{
 40	unsigned long *table, *entry;
 41
 42	table = kmem_cache_alloc(dma_page_table_cache, GFP_ATOMIC);
 43	if (!table)
 44		return NULL;
 45
 46	for (entry = table; entry < table + ZPCI_PT_ENTRIES; entry++)
 47		*entry = ZPCI_PTE_INVALID | ZPCI_TABLE_PROTECTED;
 48	return table;
 49}
 50
 51static void dma_free_page_table(void *table)
 52{
 53	kmem_cache_free(dma_page_table_cache, table);
 54}
 55
 56static unsigned long *dma_get_seg_table_origin(unsigned long *entry)
 57{
 58	unsigned long *sto;
 59
 60	if (reg_entry_isvalid(*entry))
 61		sto = get_rt_sto(*entry);
 62	else {
 63		sto = dma_alloc_cpu_table();
 64		if (!sto)
 65			return NULL;
 66
 67		set_rt_sto(entry, sto);
 68		validate_rt_entry(entry);
 69		entry_clr_protected(entry);
 70	}
 71	return sto;
 72}
 73
 74static unsigned long *dma_get_page_table_origin(unsigned long *entry)
 75{
 76	unsigned long *pto;
 77
 78	if (reg_entry_isvalid(*entry))
 79		pto = get_st_pto(*entry);
 80	else {
 81		pto = dma_alloc_page_table();
 82		if (!pto)
 83			return NULL;
 84		set_st_pto(entry, pto);
 85		validate_st_entry(entry);
 86		entry_clr_protected(entry);
 87	}
 88	return pto;
 89}
 90
 91static unsigned long *dma_walk_cpu_trans(unsigned long *rto, dma_addr_t dma_addr)
 92{
 93	unsigned long *sto, *pto;
 94	unsigned int rtx, sx, px;
 95
 96	rtx = calc_rtx(dma_addr);
 97	sto = dma_get_seg_table_origin(&rto[rtx]);
 98	if (!sto)
 99		return NULL;
100
101	sx = calc_sx(dma_addr);
102	pto = dma_get_page_table_origin(&sto[sx]);
103	if (!pto)
104		return NULL;
105
106	px = calc_px(dma_addr);
107	return &pto[px];
108}
109
110static void dma_update_cpu_trans(struct zpci_dev *zdev, void *page_addr,
111				 dma_addr_t dma_addr, int flags)
112{
113	unsigned long *entry;
114
115	entry = dma_walk_cpu_trans(zdev->dma_table, dma_addr);
116	if (!entry) {
117		WARN_ON_ONCE(1);
118		return;
119	}
120
121	if (flags & ZPCI_PTE_INVALID) {
122		invalidate_pt_entry(entry);
123		return;
124	} else {
125		set_pt_pfaa(entry, page_addr);
126		validate_pt_entry(entry);
127	}
128
129	if (flags & ZPCI_TABLE_PROTECTED)
130		entry_set_protected(entry);
131	else
132		entry_clr_protected(entry);
133}
134
135static int dma_update_trans(struct zpci_dev *zdev, unsigned long pa,
136			    dma_addr_t dma_addr, size_t size, int flags)
137{
138	unsigned int nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
139	u8 *page_addr = (u8 *) (pa & PAGE_MASK);
140	dma_addr_t start_dma_addr = dma_addr;
141	unsigned long irq_flags;
142	int i, rc = 0;
143
144	if (!nr_pages)
145		return -EINVAL;
146
147	spin_lock_irqsave(&zdev->dma_table_lock, irq_flags);
148	if (!zdev->dma_table)
149		goto no_refresh;
150
151	for (i = 0; i < nr_pages; i++) {
152		dma_update_cpu_trans(zdev, page_addr, dma_addr, flags);
153		page_addr += PAGE_SIZE;
154		dma_addr += PAGE_SIZE;
155	}
156
157	/*
158	 * rpcit is not required to establish new translations when previously
159	 * invalid translation-table entries are validated, however it is
160	 * required when altering previously valid entries.
161	 */
162	if (!zdev->tlb_refresh &&
163	    ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID))
164		/*
165		 * TODO: also need to check that the old entry is indeed INVALID
166		 * and not only for one page but for the whole range...
167		 * -> now we WARN_ON in that case but with lazy unmap that
168		 * needs to be redone!
169		 */
170		goto no_refresh;
171
172	rc = zpci_refresh_trans((u64) zdev->fh << 32, start_dma_addr,
173				nr_pages * PAGE_SIZE);
174
175no_refresh:
176	spin_unlock_irqrestore(&zdev->dma_table_lock, irq_flags);
177	return rc;
178}
179
180static void dma_free_seg_table(unsigned long entry)
181{
182	unsigned long *sto = get_rt_sto(entry);
183	int sx;
184
185	for (sx = 0; sx < ZPCI_TABLE_ENTRIES; sx++)
186		if (reg_entry_isvalid(sto[sx]))
187			dma_free_page_table(get_st_pto(sto[sx]));
188
189	dma_free_cpu_table(sto);
190}
191
192static void dma_cleanup_tables(struct zpci_dev *zdev)
193{
194	unsigned long *table;
195	int rtx;
196
197	if (!zdev || !zdev->dma_table)
198		return;
199
200	table = zdev->dma_table;
201	for (rtx = 0; rtx < ZPCI_TABLE_ENTRIES; rtx++)
202		if (reg_entry_isvalid(table[rtx]))
203			dma_free_seg_table(table[rtx]);
204
205	dma_free_cpu_table(table);
206	zdev->dma_table = NULL;
207}
208
209static unsigned long __dma_alloc_iommu(struct zpci_dev *zdev,
210				       unsigned long start, int size)
211{
212	unsigned long boundary_size;
213
214	boundary_size = ALIGN(dma_get_seg_boundary(&zdev->pdev->dev) + 1,
215			      PAGE_SIZE) >> PAGE_SHIFT;
216	return iommu_area_alloc(zdev->iommu_bitmap, zdev->iommu_pages,
217				start, size, 0, boundary_size, 0);
218}
219
220static unsigned long dma_alloc_iommu(struct zpci_dev *zdev, int size)
221{
222	unsigned long offset, flags;
223
224	spin_lock_irqsave(&zdev->iommu_bitmap_lock, flags);
225	offset = __dma_alloc_iommu(zdev, zdev->next_bit, size);
226	if (offset == -1)
227		offset = __dma_alloc_iommu(zdev, 0, size);
228
229	if (offset != -1) {
230		zdev->next_bit = offset + size;
231		if (zdev->next_bit >= zdev->iommu_pages)
232			zdev->next_bit = 0;
233	}
234	spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags);
235	return offset;
236}
237
238static void dma_free_iommu(struct zpci_dev *zdev, unsigned long offset, int size)
239{
240	unsigned long flags;
241
242	spin_lock_irqsave(&zdev->iommu_bitmap_lock, flags);
243	if (!zdev->iommu_bitmap)
244		goto out;
245	bitmap_clear(zdev->iommu_bitmap, offset, size);
246	if (offset >= zdev->next_bit)
247		zdev->next_bit = offset + size;
248out:
249	spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags);
250}
251
252int dma_set_mask(struct device *dev, u64 mask)
253{
254	if (!dev->dma_mask || !dma_supported(dev, mask))
255		return -EIO;
256
257	*dev->dma_mask = mask;
258	return 0;
259}
260EXPORT_SYMBOL_GPL(dma_set_mask);
261
262static dma_addr_t s390_dma_map_pages(struct device *dev, struct page *page,
263				     unsigned long offset, size_t size,
264				     enum dma_data_direction direction,
265				     struct dma_attrs *attrs)
266{
267	struct zpci_dev *zdev = get_zdev(to_pci_dev(dev));
268	unsigned long nr_pages, iommu_page_index;
269	unsigned long pa = page_to_phys(page) + offset;
270	int flags = ZPCI_PTE_VALID;
271	dma_addr_t dma_addr;
272
273	/* This rounds up number of pages based on size and offset */
274	nr_pages = iommu_num_pages(pa, size, PAGE_SIZE);
275	iommu_page_index = dma_alloc_iommu(zdev, nr_pages);
276	if (iommu_page_index == -1)
277		goto out_err;
278
279	/* Use rounded up size */
280	size = nr_pages * PAGE_SIZE;
281
282	dma_addr = zdev->start_dma + iommu_page_index * PAGE_SIZE;
283	if (dma_addr + size > zdev->end_dma)
284		goto out_free;
285
286	if (direction == DMA_NONE || direction == DMA_TO_DEVICE)
287		flags |= ZPCI_TABLE_PROTECTED;
288
289	if (!dma_update_trans(zdev, pa, dma_addr, size, flags)) {
290		atomic64_add(nr_pages, &zdev->fmb->mapped_pages);
291		return dma_addr + (offset & ~PAGE_MASK);
292	}
293
294out_free:
295	dma_free_iommu(zdev, iommu_page_index, nr_pages);
296out_err:
297	zpci_err("map error:\n");
298	zpci_err_hex(&pa, sizeof(pa));
299	return DMA_ERROR_CODE;
300}
301
302static void s390_dma_unmap_pages(struct device *dev, dma_addr_t dma_addr,
303				 size_t size, enum dma_data_direction direction,
304				 struct dma_attrs *attrs)
305{
306	struct zpci_dev *zdev = get_zdev(to_pci_dev(dev));
307	unsigned long iommu_page_index;
308	int npages;
309
310	npages = iommu_num_pages(dma_addr, size, PAGE_SIZE);
311	dma_addr = dma_addr & PAGE_MASK;
312	if (dma_update_trans(zdev, 0, dma_addr, npages * PAGE_SIZE,
313			     ZPCI_TABLE_PROTECTED | ZPCI_PTE_INVALID)) {
314		zpci_err("unmap error:\n");
315		zpci_err_hex(&dma_addr, sizeof(dma_addr));
316	}
317
318	atomic64_add(npages, &zdev->fmb->unmapped_pages);
319	iommu_page_index = (dma_addr - zdev->start_dma) >> PAGE_SHIFT;
320	dma_free_iommu(zdev, iommu_page_index, npages);
321}
322
323static void *s390_dma_alloc(struct device *dev, size_t size,
324			    dma_addr_t *dma_handle, gfp_t flag,
325			    struct dma_attrs *attrs)
326{
327	struct zpci_dev *zdev = get_zdev(to_pci_dev(dev));
328	struct page *page;
329	unsigned long pa;
330	dma_addr_t map;
331
332	size = PAGE_ALIGN(size);
333	page = alloc_pages(flag, get_order(size));
334	if (!page)
335		return NULL;
336
337	pa = page_to_phys(page);
338	memset((void *) pa, 0, size);
339
340	map = s390_dma_map_pages(dev, page, pa % PAGE_SIZE,
341				 size, DMA_BIDIRECTIONAL, NULL);
342	if (dma_mapping_error(dev, map)) {
343		free_pages(pa, get_order(size));
344		return NULL;
345	}
346
347	atomic64_add(size / PAGE_SIZE, &zdev->fmb->allocated_pages);
348	if (dma_handle)
349		*dma_handle = map;
350	return (void *) pa;
351}
352
353static void s390_dma_free(struct device *dev, size_t size,
354			  void *pa, dma_addr_t dma_handle,
355			  struct dma_attrs *attrs)
356{
357	struct zpci_dev *zdev = get_zdev(to_pci_dev(dev));
358
359	size = PAGE_ALIGN(size);
360	atomic64_sub(size / PAGE_SIZE, &zdev->fmb->allocated_pages);
361	s390_dma_unmap_pages(dev, dma_handle, size, DMA_BIDIRECTIONAL, NULL);
362	free_pages((unsigned long) pa, get_order(size));
363}
364
365static int s390_dma_map_sg(struct device *dev, struct scatterlist *sg,
366			   int nr_elements, enum dma_data_direction dir,
367			   struct dma_attrs *attrs)
368{
369	int mapped_elements = 0;
370	struct scatterlist *s;
371	int i;
372
373	for_each_sg(sg, s, nr_elements, i) {
374		struct page *page = sg_page(s);
375		s->dma_address = s390_dma_map_pages(dev, page, s->offset,
376						    s->length, dir, NULL);
377		if (!dma_mapping_error(dev, s->dma_address)) {
378			s->dma_length = s->length;
379			mapped_elements++;
380		} else
381			goto unmap;
382	}
383out:
384	return mapped_elements;
385
386unmap:
387	for_each_sg(sg, s, mapped_elements, i) {
388		if (s->dma_address)
389			s390_dma_unmap_pages(dev, s->dma_address, s->dma_length,
390					     dir, NULL);
391		s->dma_address = 0;
392		s->dma_length = 0;
393	}
394	mapped_elements = 0;
395	goto out;
396}
397
398static void s390_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
399			      int nr_elements, enum dma_data_direction dir,
400			      struct dma_attrs *attrs)
401{
402	struct scatterlist *s;
403	int i;
404
405	for_each_sg(sg, s, nr_elements, i) {
406		s390_dma_unmap_pages(dev, s->dma_address, s->dma_length, dir, NULL);
407		s->dma_address = 0;
408		s->dma_length = 0;
409	}
410}
411
412int zpci_dma_init_device(struct zpci_dev *zdev)
413{
414	int rc;
415
416	spin_lock_init(&zdev->iommu_bitmap_lock);
417	spin_lock_init(&zdev->dma_table_lock);
418
419	zdev->dma_table = dma_alloc_cpu_table();
420	if (!zdev->dma_table) {
421		rc = -ENOMEM;
422		goto out_clean;
423	}
424
425	zdev->iommu_size = (unsigned long) high_memory - PAGE_OFFSET;
426	zdev->iommu_pages = zdev->iommu_size >> PAGE_SHIFT;
427	zdev->iommu_bitmap = vzalloc(zdev->iommu_pages / 8);
428	if (!zdev->iommu_bitmap) {
429		rc = -ENOMEM;
430		goto out_reg;
431	}
432
433	rc = zpci_register_ioat(zdev,
434				0,
435				zdev->start_dma + PAGE_OFFSET,
436				zdev->start_dma + zdev->iommu_size - 1,
437				(u64) zdev->dma_table);
438	if (rc)
439		goto out_reg;
440	return 0;
441
442out_reg:
443	dma_free_cpu_table(zdev->dma_table);
444out_clean:
445	return rc;
446}
447
448void zpci_dma_exit_device(struct zpci_dev *zdev)
449{
450	zpci_unregister_ioat(zdev, 0);
451	dma_cleanup_tables(zdev);
452	vfree(zdev->iommu_bitmap);
453	zdev->iommu_bitmap = NULL;
454	zdev->next_bit = 0;
455}
456
457static int __init dma_alloc_cpu_table_caches(void)
458{
459	dma_region_table_cache = kmem_cache_create("PCI_DMA_region_tables",
460					ZPCI_TABLE_SIZE, ZPCI_TABLE_ALIGN,
461					0, NULL);
462	if (!dma_region_table_cache)
463		return -ENOMEM;
464
465	dma_page_table_cache = kmem_cache_create("PCI_DMA_page_tables",
466					ZPCI_PT_SIZE, ZPCI_PT_ALIGN,
467					0, NULL);
468	if (!dma_page_table_cache) {
469		kmem_cache_destroy(dma_region_table_cache);
470		return -ENOMEM;
471	}
472	return 0;
473}
474
475int __init zpci_dma_init(void)
476{
477	return dma_alloc_cpu_table_caches();
478}
479
480void zpci_dma_exit(void)
481{
482	kmem_cache_destroy(dma_page_table_cache);
483	kmem_cache_destroy(dma_region_table_cache);
484}
485
486#define PREALLOC_DMA_DEBUG_ENTRIES	(1 << 16)
487
488static int __init dma_debug_do_init(void)
489{
490	dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
491	return 0;
492}
493fs_initcall(dma_debug_do_init);
494
495struct dma_map_ops s390_dma_ops = {
496	.alloc		= s390_dma_alloc,
497	.free		= s390_dma_free,
498	.map_sg		= s390_dma_map_sg,
499	.unmap_sg	= s390_dma_unmap_sg,
500	.map_page	= s390_dma_map_pages,
501	.unmap_page	= s390_dma_unmap_pages,
502	/* if we support direct DMA this must be conditional */
503	.is_phys	= 0,
504	/* dma_supported is unconditionally true without a callback */
505};
506EXPORT_SYMBOL_GPL(s390_dma_ops);