1 /*
2 * arch/powerpc/sysdev/dart_iommu.c
3 *
4 * Copyright (C) 2004 Olof Johansson <olof@lixom.net>, IBM Corporation
5 * Copyright (C) 2005 Benjamin Herrenschmidt <benh@kernel.crashing.org>,
6 * IBM Corporation
7 *
8 * Based on pSeries_iommu.c:
9 * Copyright (C) 2001 Mike Corrigan & Dave Engebretsen, IBM Corporation
10 * Copyright (C) 2004 Olof Johansson <olof@lixom.net>, IBM Corporation
11 *
12 * Dynamic DMA mapping support, Apple U3, U4 & IBM CPC925 "DART" iommu.
13 *
14 *
15 * This program is free software; you can redistribute it and/or modify
16 * it under the terms of the GNU General Public License as published by
17 * the Free Software Foundation; either version 2 of the License, or
18 * (at your option) any later version.
19 *
20 * This program is distributed in the hope that it will be useful,
21 * but WITHOUT ANY WARRANTY; without even the implied warranty of
22 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
23 * GNU General Public License for more details.
24 *
25 * You should have received a copy of the GNU General Public License
26 * along with this program; if not, write to the Free Software
27 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
28 */
29
30 #include <linux/init.h>
31 #include <linux/types.h>
32 #include <linux/mm.h>
33 #include <linux/spinlock.h>
34 #include <linux/string.h>
35 #include <linux/pci.h>
36 #include <linux/dma-mapping.h>
37 #include <linux/vmalloc.h>
38 #include <linux/suspend.h>
39 #include <linux/memblock.h>
40 #include <linux/gfp.h>
41 #include <asm/io.h>
42 #include <asm/prom.h>
43 #include <asm/iommu.h>
44 #include <asm/pci-bridge.h>
45 #include <asm/machdep.h>
46 #include <asm/cacheflush.h>
47 #include <asm/ppc-pci.h>
48
49 #include "dart.h"
50
51 /* Physical base address and size of the DART table */
52 unsigned long dart_tablebase; /* exported to htab_initialize */
53 static unsigned long dart_tablesize;
54
55 /* Virtual base address of the DART table */
56 static u32 *dart_vbase;
57 #ifdef CONFIG_PM
58 static u32 *dart_copy;
59 #endif
60
61 /* Mapped base address for the dart */
62 static unsigned int __iomem *dart;
63
64 /* Dummy val that entries are set to when unused */
65 static unsigned int dart_emptyval;
66
67 static struct iommu_table iommu_table_dart;
68 static int iommu_table_dart_inited;
69 static int dart_dirty;
70 static int dart_is_u4;
71
72 #define DART_U4_BYPASS_BASE 0x8000000000ull
73
74 #define DBG(...)
75
76 static DEFINE_SPINLOCK(invalidate_lock);
77
dart_tlb_invalidate_all(void)78 static inline void dart_tlb_invalidate_all(void)
79 {
80 unsigned long l = 0;
81 unsigned int reg, inv_bit;
82 unsigned long limit;
83 unsigned long flags;
84
85 spin_lock_irqsave(&invalidate_lock, flags);
86
87 DBG("dart: flush\n");
88
89 /* To invalidate the DART, set the DARTCNTL_FLUSHTLB bit in the
90 * control register and wait for it to clear.
91 *
92 * Gotcha: Sometimes, the DART won't detect that the bit gets
93 * set. If so, clear it and set it again.
94 */
95
96 limit = 0;
97
98 inv_bit = dart_is_u4 ? DART_CNTL_U4_FLUSHTLB : DART_CNTL_U3_FLUSHTLB;
99 retry:
100 l = 0;
101 reg = DART_IN(DART_CNTL);
102 reg |= inv_bit;
103 DART_OUT(DART_CNTL, reg);
104
105 while ((DART_IN(DART_CNTL) & inv_bit) && l < (1L << limit))
106 l++;
107 if (l == (1L << limit)) {
108 if (limit < 4) {
109 limit++;
110 reg = DART_IN(DART_CNTL);
111 reg &= ~inv_bit;
112 DART_OUT(DART_CNTL, reg);
113 goto retry;
114 } else
115 panic("DART: TLB did not flush after waiting a long "
116 "time. Buggy U3 ?");
117 }
118
119 spin_unlock_irqrestore(&invalidate_lock, flags);
120 }
121
dart_tlb_invalidate_one(unsigned long bus_rpn)122 static inline void dart_tlb_invalidate_one(unsigned long bus_rpn)
123 {
124 unsigned int reg;
125 unsigned int l, limit;
126 unsigned long flags;
127
128 spin_lock_irqsave(&invalidate_lock, flags);
129
130 reg = DART_CNTL_U4_ENABLE | DART_CNTL_U4_IONE |
131 (bus_rpn & DART_CNTL_U4_IONE_MASK);
132 DART_OUT(DART_CNTL, reg);
133
134 limit = 0;
135 wait_more:
136 l = 0;
137 while ((DART_IN(DART_CNTL) & DART_CNTL_U4_IONE) && l < (1L << limit)) {
138 rmb();
139 l++;
140 }
141
142 if (l == (1L << limit)) {
143 if (limit < 4) {
144 limit++;
145 goto wait_more;
146 } else
147 panic("DART: TLB did not flush after waiting a long "
148 "time. Buggy U4 ?");
149 }
150
151 spin_unlock_irqrestore(&invalidate_lock, flags);
152 }
153
dart_flush(struct iommu_table * tbl)154 static void dart_flush(struct iommu_table *tbl)
155 {
156 mb();
157 if (dart_dirty) {
158 dart_tlb_invalidate_all();
159 dart_dirty = 0;
160 }
161 }
162
dart_build(struct iommu_table * tbl,long index,long npages,unsigned long uaddr,enum dma_data_direction direction,struct dma_attrs * attrs)163 static int dart_build(struct iommu_table *tbl, long index,
164 long npages, unsigned long uaddr,
165 enum dma_data_direction direction,
166 struct dma_attrs *attrs)
167 {
168 unsigned int *dp;
169 unsigned int rpn;
170 long l;
171
172 DBG("dart: build at: %lx, %lx, addr: %x\n", index, npages, uaddr);
173
174 dp = ((unsigned int*)tbl->it_base) + index;
175
176 /* On U3, all memory is contiguous, so we can move this
177 * out of the loop.
178 */
179 l = npages;
180 while (l--) {
181 rpn = __pa(uaddr) >> DART_PAGE_SHIFT;
182
183 *(dp++) = DARTMAP_VALID | (rpn & DARTMAP_RPNMASK);
184
185 uaddr += DART_PAGE_SIZE;
186 }
187
188 /* make sure all updates have reached memory */
189 mb();
190 in_be32((unsigned __iomem *)dp);
191 mb();
192
193 if (dart_is_u4) {
194 rpn = index;
195 while (npages--)
196 dart_tlb_invalidate_one(rpn++);
197 } else {
198 dart_dirty = 1;
199 }
200 return 0;
201 }
202
203
dart_free(struct iommu_table * tbl,long index,long npages)204 static void dart_free(struct iommu_table *tbl, long index, long npages)
205 {
206 unsigned int *dp;
207
208 /* We don't worry about flushing the TLB cache. The only drawback of
209 * not doing it is that we won't catch buggy device drivers doing
210 * bad DMAs, but then no 32-bit architecture ever does either.
211 */
212
213 DBG("dart: free at: %lx, %lx\n", index, npages);
214
215 dp = ((unsigned int *)tbl->it_base) + index;
216
217 while (npages--)
218 *(dp++) = dart_emptyval;
219 }
220
221
dart_init(struct device_node * dart_node)222 static int __init dart_init(struct device_node *dart_node)
223 {
224 unsigned int i;
225 unsigned long tmp, base, size;
226 struct resource r;
227
228 if (dart_tablebase == 0 || dart_tablesize == 0) {
229 printk(KERN_INFO "DART: table not allocated, using "
230 "direct DMA\n");
231 return -ENODEV;
232 }
233
234 if (of_address_to_resource(dart_node, 0, &r))
235 panic("DART: can't get register base ! ");
236
237 /* Make sure nothing from the DART range remains in the CPU cache
238 * from a previous mapping that existed before the kernel took
239 * over
240 */
241 flush_dcache_phys_range(dart_tablebase,
242 dart_tablebase + dart_tablesize);
243
244 /* Allocate a spare page to map all invalid DART pages. We need to do
245 * that to work around what looks like a problem with the HT bridge
246 * prefetching into invalid pages and corrupting data
247 */
248 tmp = memblock_alloc(DART_PAGE_SIZE, DART_PAGE_SIZE);
249 dart_emptyval = DARTMAP_VALID | ((tmp >> DART_PAGE_SHIFT) &
250 DARTMAP_RPNMASK);
251
252 /* Map in DART registers */
253 dart = ioremap(r.start, resource_size(&r));
254 if (dart == NULL)
255 panic("DART: Cannot map registers!");
256
257 /* Map in DART table */
258 dart_vbase = ioremap(__pa(dart_tablebase), dart_tablesize);
259
260 /* Fill initial table */
261 for (i = 0; i < dart_tablesize/4; i++)
262 dart_vbase[i] = dart_emptyval;
263
264 /* Initialize DART with table base and enable it. */
265 base = dart_tablebase >> DART_PAGE_SHIFT;
266 size = dart_tablesize >> DART_PAGE_SHIFT;
267 if (dart_is_u4) {
268 size &= DART_SIZE_U4_SIZE_MASK;
269 DART_OUT(DART_BASE_U4, base);
270 DART_OUT(DART_SIZE_U4, size);
271 DART_OUT(DART_CNTL, DART_CNTL_U4_ENABLE);
272 } else {
273 size &= DART_CNTL_U3_SIZE_MASK;
274 DART_OUT(DART_CNTL,
275 DART_CNTL_U3_ENABLE |
276 (base << DART_CNTL_U3_BASE_SHIFT) |
277 (size << DART_CNTL_U3_SIZE_SHIFT));
278 }
279
280 /* Invalidate DART to get rid of possible stale TLBs */
281 dart_tlb_invalidate_all();
282
283 printk(KERN_INFO "DART IOMMU initialized for %s type chipset\n",
284 dart_is_u4 ? "U4" : "U3");
285
286 return 0;
287 }
288
iommu_table_dart_setup(void)289 static void iommu_table_dart_setup(void)
290 {
291 iommu_table_dart.it_busno = 0;
292 iommu_table_dart.it_offset = 0;
293 /* it_size is in number of entries */
294 iommu_table_dart.it_size = dart_tablesize / sizeof(u32);
295 iommu_table_dart.it_page_shift = IOMMU_PAGE_SHIFT_4K;
296
297 /* Initialize the common IOMMU code */
298 iommu_table_dart.it_base = (unsigned long)dart_vbase;
299 iommu_table_dart.it_index = 0;
300 iommu_table_dart.it_blocksize = 1;
301 iommu_init_table(&iommu_table_dart, -1);
302
303 /* Reserve the last page of the DART to avoid possible prefetch
304 * past the DART mapped area
305 */
306 set_bit(iommu_table_dart.it_size - 1, iommu_table_dart.it_map);
307 }
308
dma_dev_setup_dart(struct device * dev)309 static void dma_dev_setup_dart(struct device *dev)
310 {
311 /* We only have one iommu table on the mac for now, which makes
312 * things simple. Setup all PCI devices to point to this table
313 */
314 if (get_dma_ops(dev) == &dma_direct_ops)
315 set_dma_offset(dev, DART_U4_BYPASS_BASE);
316 else
317 set_iommu_table_base(dev, &iommu_table_dart);
318 }
319
pci_dma_dev_setup_dart(struct pci_dev * dev)320 static void pci_dma_dev_setup_dart(struct pci_dev *dev)
321 {
322 dma_dev_setup_dart(&dev->dev);
323 }
324
pci_dma_bus_setup_dart(struct pci_bus * bus)325 static void pci_dma_bus_setup_dart(struct pci_bus *bus)
326 {
327 if (!iommu_table_dart_inited) {
328 iommu_table_dart_inited = 1;
329 iommu_table_dart_setup();
330 }
331 }
332
dart_device_on_pcie(struct device * dev)333 static bool dart_device_on_pcie(struct device *dev)
334 {
335 struct device_node *np = of_node_get(dev->of_node);
336
337 while(np) {
338 if (of_device_is_compatible(np, "U4-pcie") ||
339 of_device_is_compatible(np, "u4-pcie")) {
340 of_node_put(np);
341 return true;
342 }
343 np = of_get_next_parent(np);
344 }
345 return false;
346 }
347
dart_dma_set_mask(struct device * dev,u64 dma_mask)348 static int dart_dma_set_mask(struct device *dev, u64 dma_mask)
349 {
350 if (!dev->dma_mask || !dma_supported(dev, dma_mask))
351 return -EIO;
352
353 /* U4 supports a DART bypass, we use it for 64-bit capable
354 * devices to improve performances. However, that only works
355 * for devices connected to U4 own PCIe interface, not bridged
356 * through hypertransport. We need the device to support at
357 * least 40 bits of addresses.
358 */
359 if (dart_device_on_pcie(dev) && dma_mask >= DMA_BIT_MASK(40)) {
360 dev_info(dev, "Using 64-bit DMA iommu bypass\n");
361 set_dma_ops(dev, &dma_direct_ops);
362 } else {
363 dev_info(dev, "Using 32-bit DMA via iommu\n");
364 set_dma_ops(dev, &dma_iommu_ops);
365 }
366 dma_dev_setup_dart(dev);
367
368 *dev->dma_mask = dma_mask;
369 return 0;
370 }
371
iommu_init_early_dart(void)372 void __init iommu_init_early_dart(void)
373 {
374 struct device_node *dn;
375
376 /* Find the DART in the device-tree */
377 dn = of_find_compatible_node(NULL, "dart", "u3-dart");
378 if (dn == NULL) {
379 dn = of_find_compatible_node(NULL, "dart", "u4-dart");
380 if (dn == NULL)
381 return; /* use default direct_dma_ops */
382 dart_is_u4 = 1;
383 }
384
385 /* Initialize the DART HW */
386 if (dart_init(dn) != 0)
387 goto bail;
388
389 /* Setup low level TCE operations for the core IOMMU code */
390 ppc_md.tce_build = dart_build;
391 ppc_md.tce_free = dart_free;
392 ppc_md.tce_flush = dart_flush;
393
394 /* Setup bypass if supported */
395 if (dart_is_u4)
396 ppc_md.dma_set_mask = dart_dma_set_mask;
397
398 ppc_md.pci_dma_dev_setup = pci_dma_dev_setup_dart;
399 ppc_md.pci_dma_bus_setup = pci_dma_bus_setup_dart;
400
401 /* Setup pci_dma ops */
402 set_pci_dma_ops(&dma_iommu_ops);
403 return;
404
405 bail:
406 /* If init failed, use direct iommu and null setup functions */
407 ppc_md.pci_dma_dev_setup = NULL;
408 ppc_md.pci_dma_bus_setup = NULL;
409
410 /* Setup pci_dma ops */
411 set_pci_dma_ops(&dma_direct_ops);
412 }
413
414 #ifdef CONFIG_PM
iommu_dart_save(void)415 static void iommu_dart_save(void)
416 {
417 memcpy(dart_copy, dart_vbase, 2*1024*1024);
418 }
419
iommu_dart_restore(void)420 static void iommu_dart_restore(void)
421 {
422 memcpy(dart_vbase, dart_copy, 2*1024*1024);
423 dart_tlb_invalidate_all();
424 }
425
iommu_init_late_dart(void)426 static int __init iommu_init_late_dart(void)
427 {
428 unsigned long tbasepfn;
429 struct page *p;
430
431 /* if no dart table exists then we won't need to save it
432 * and the area has also not been reserved */
433 if (!dart_tablebase)
434 return 0;
435
436 tbasepfn = __pa(dart_tablebase) >> PAGE_SHIFT;
437 register_nosave_region_late(tbasepfn,
438 tbasepfn + ((1<<24) >> PAGE_SHIFT));
439
440 /* For suspend we need to copy the dart contents because
441 * it is not part of the regular mapping (see above) and
442 * thus not saved automatically. The memory for this copy
443 * must be allocated early because we need 2 MB. */
444 p = alloc_pages(GFP_KERNEL, 21 - PAGE_SHIFT);
445 BUG_ON(!p);
446 dart_copy = page_address(p);
447
448 ppc_md.iommu_save = iommu_dart_save;
449 ppc_md.iommu_restore = iommu_dart_restore;
450
451 return 0;
452 }
453
454 late_initcall(iommu_init_late_dart);
455 #endif
456
alloc_dart_table(void)457 void __init alloc_dart_table(void)
458 {
459 /* Only reserve DART space if machine has more than 1GB of RAM
460 * or if requested with iommu=on on cmdline.
461 *
462 * 1GB of RAM is picked as limit because some default devices
463 * (i.e. Airport Extreme) have 30 bit address range limits.
464 */
465
466 if (iommu_is_off)
467 return;
468
469 if (!iommu_force_on && memblock_end_of_DRAM() <= 0x40000000ull)
470 return;
471
472 /* 512 pages (2MB) is max DART tablesize. */
473 dart_tablesize = 1UL << 21;
474 /* 16MB (1 << 24) alignment. We allocate a full 16Mb chuck since we
475 * will blow up an entire large page anyway in the kernel mapping
476 */
477 dart_tablebase = (unsigned long)
478 __va(memblock_alloc_base(1UL<<24, 1UL<<24, 0x80000000L));
479 /*
480 * The DART space is later unmapped from the kernel linear mapping and
481 * accessing dart_tablebase during kmemleak scanning will fault.
482 */
483 kmemleak_no_scan((void *)dart_tablebase);
484
485 printk(KERN_INFO "DART table allocated at: %lx\n", dart_tablebase);
486 }
487