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 <linux/kmemleak.h>
42 #include <asm/io.h>
43 #include <asm/prom.h>
44 #include <asm/iommu.h>
45 #include <asm/pci-bridge.h>
46 #include <asm/machdep.h>
47 #include <asm/cacheflush.h>
48 #include <asm/ppc-pci.h>
49
50 #include "dart.h"
51
52 /* DART table address and size */
53 static u32 *dart_tablebase;
54 static unsigned long dart_tablesize;
55
56 /* Mapped base address for the dart */
57 static unsigned int __iomem *dart;
58
59 /* Dummy val that entries are set to when unused */
60 static unsigned int dart_emptyval;
61
62 static struct iommu_table iommu_table_dart;
63 static int iommu_table_dart_inited;
64 static int dart_dirty;
65 static int dart_is_u4;
66
67 #define DART_U4_BYPASS_BASE 0x8000000000ull
68
69 #define DBG(...)
70
71 static DEFINE_SPINLOCK(invalidate_lock);
72
dart_tlb_invalidate_all(void)73 static inline void dart_tlb_invalidate_all(void)
74 {
75 unsigned long l = 0;
76 unsigned int reg, inv_bit;
77 unsigned long limit;
78 unsigned long flags;
79
80 spin_lock_irqsave(&invalidate_lock, flags);
81
82 DBG("dart: flush\n");
83
84 /* To invalidate the DART, set the DARTCNTL_FLUSHTLB bit in the
85 * control register and wait for it to clear.
86 *
87 * Gotcha: Sometimes, the DART won't detect that the bit gets
88 * set. If so, clear it and set it again.
89 */
90
91 limit = 0;
92
93 inv_bit = dart_is_u4 ? DART_CNTL_U4_FLUSHTLB : DART_CNTL_U3_FLUSHTLB;
94 retry:
95 l = 0;
96 reg = DART_IN(DART_CNTL);
97 reg |= inv_bit;
98 DART_OUT(DART_CNTL, reg);
99
100 while ((DART_IN(DART_CNTL) & inv_bit) && l < (1L << limit))
101 l++;
102 if (l == (1L << limit)) {
103 if (limit < 4) {
104 limit++;
105 reg = DART_IN(DART_CNTL);
106 reg &= ~inv_bit;
107 DART_OUT(DART_CNTL, reg);
108 goto retry;
109 } else
110 panic("DART: TLB did not flush after waiting a long "
111 "time. Buggy U3 ?");
112 }
113
114 spin_unlock_irqrestore(&invalidate_lock, flags);
115 }
116
dart_tlb_invalidate_one(unsigned long bus_rpn)117 static inline void dart_tlb_invalidate_one(unsigned long bus_rpn)
118 {
119 unsigned int reg;
120 unsigned int l, limit;
121 unsigned long flags;
122
123 spin_lock_irqsave(&invalidate_lock, flags);
124
125 reg = DART_CNTL_U4_ENABLE | DART_CNTL_U4_IONE |
126 (bus_rpn & DART_CNTL_U4_IONE_MASK);
127 DART_OUT(DART_CNTL, reg);
128
129 limit = 0;
130 wait_more:
131 l = 0;
132 while ((DART_IN(DART_CNTL) & DART_CNTL_U4_IONE) && l < (1L << limit)) {
133 rmb();
134 l++;
135 }
136
137 if (l == (1L << limit)) {
138 if (limit < 4) {
139 limit++;
140 goto wait_more;
141 } else
142 panic("DART: TLB did not flush after waiting a long "
143 "time. Buggy U4 ?");
144 }
145
146 spin_unlock_irqrestore(&invalidate_lock, flags);
147 }
148
dart_cache_sync(unsigned int * base,unsigned int count)149 static void dart_cache_sync(unsigned int *base, unsigned int count)
150 {
151 /*
152 * We add 1 to the number of entries to flush, following a
153 * comment in Darwin indicating that the memory controller
154 * can prefetch unmapped memory under some circumstances.
155 */
156 unsigned long start = (unsigned long)base;
157 unsigned long end = start + (count + 1) * sizeof(unsigned int);
158 unsigned int tmp;
159
160 /* Perform a standard cache flush */
161 flush_inval_dcache_range(start, end);
162
163 /*
164 * Perform the sequence described in the CPC925 manual to
165 * ensure all the data gets to a point the cache incoherent
166 * DART hardware will see.
167 */
168 asm volatile(" sync;"
169 " isync;"
170 " dcbf 0,%1;"
171 " sync;"
172 " isync;"
173 " lwz %0,0(%1);"
174 " isync" : "=r" (tmp) : "r" (end) : "memory");
175 }
176
dart_flush(struct iommu_table * tbl)177 static void dart_flush(struct iommu_table *tbl)
178 {
179 mb();
180 if (dart_dirty) {
181 dart_tlb_invalidate_all();
182 dart_dirty = 0;
183 }
184 }
185
dart_build(struct iommu_table * tbl,long index,long npages,unsigned long uaddr,enum dma_data_direction direction,unsigned long attrs)186 static int dart_build(struct iommu_table *tbl, long index,
187 long npages, unsigned long uaddr,
188 enum dma_data_direction direction,
189 unsigned long attrs)
190 {
191 unsigned int *dp, *orig_dp;
192 unsigned int rpn;
193 long l;
194
195 DBG("dart: build at: %lx, %lx, addr: %x\n", index, npages, uaddr);
196
197 orig_dp = dp = ((unsigned int*)tbl->it_base) + index;
198
199 /* On U3, all memory is contiguous, so we can move this
200 * out of the loop.
201 */
202 l = npages;
203 while (l--) {
204 rpn = __pa(uaddr) >> DART_PAGE_SHIFT;
205
206 *(dp++) = DARTMAP_VALID | (rpn & DARTMAP_RPNMASK);
207
208 uaddr += DART_PAGE_SIZE;
209 }
210 dart_cache_sync(orig_dp, npages);
211
212 if (dart_is_u4) {
213 rpn = index;
214 while (npages--)
215 dart_tlb_invalidate_one(rpn++);
216 } else {
217 dart_dirty = 1;
218 }
219 return 0;
220 }
221
222
dart_free(struct iommu_table * tbl,long index,long npages)223 static void dart_free(struct iommu_table *tbl, long index, long npages)
224 {
225 unsigned int *dp, *orig_dp;
226 long orig_npages = npages;
227
228 /* We don't worry about flushing the TLB cache. The only drawback of
229 * not doing it is that we won't catch buggy device drivers doing
230 * bad DMAs, but then no 32-bit architecture ever does either.
231 */
232
233 DBG("dart: free at: %lx, %lx\n", index, npages);
234
235 orig_dp = dp = ((unsigned int *)tbl->it_base) + index;
236
237 while (npages--)
238 *(dp++) = dart_emptyval;
239
240 dart_cache_sync(orig_dp, orig_npages);
241 }
242
allocate_dart(void)243 static void allocate_dart(void)
244 {
245 unsigned long tmp;
246
247 /* 512 pages (2MB) is max DART tablesize. */
248 dart_tablesize = 1UL << 21;
249
250 /*
251 * 16MB (1 << 24) alignment. We allocate a full 16Mb chuck since we
252 * will blow up an entire large page anyway in the kernel mapping.
253 */
254 dart_tablebase = __va(memblock_alloc_base(1UL<<24,
255 1UL<<24, 0x80000000L));
256
257 /* There is no point scanning the DART space for leaks*/
258 kmemleak_no_scan((void *)dart_tablebase);
259
260 /* Allocate a spare page to map all invalid DART pages. We need to do
261 * that to work around what looks like a problem with the HT bridge
262 * prefetching into invalid pages and corrupting data
263 */
264 tmp = memblock_alloc(DART_PAGE_SIZE, DART_PAGE_SIZE);
265 dart_emptyval = DARTMAP_VALID | ((tmp >> DART_PAGE_SHIFT) &
266 DARTMAP_RPNMASK);
267
268 printk(KERN_INFO "DART table allocated at: %p\n", dart_tablebase);
269 }
270
dart_init(struct device_node * dart_node)271 static int __init dart_init(struct device_node *dart_node)
272 {
273 unsigned int i;
274 unsigned long base, size;
275 struct resource r;
276
277 /* IOMMU disabled by the user ? bail out */
278 if (iommu_is_off)
279 return -ENODEV;
280
281 /*
282 * Only use the DART if the machine has more than 1GB of RAM
283 * or if requested with iommu=on on cmdline.
284 *
285 * 1GB of RAM is picked as limit because some default devices
286 * (i.e. Airport Extreme) have 30 bit address range limits.
287 */
288
289 if (!iommu_force_on && memblock_end_of_DRAM() <= 0x40000000ull)
290 return -ENODEV;
291
292 /* Get DART registers */
293 if (of_address_to_resource(dart_node, 0, &r))
294 panic("DART: can't get register base ! ");
295
296 /* Map in DART registers */
297 dart = ioremap(r.start, resource_size(&r));
298 if (dart == NULL)
299 panic("DART: Cannot map registers!");
300
301 /* Allocate the DART and dummy page */
302 allocate_dart();
303
304 /* Fill initial table */
305 for (i = 0; i < dart_tablesize/4; i++)
306 dart_tablebase[i] = dart_emptyval;
307
308 /* Push to memory */
309 dart_cache_sync(dart_tablebase, dart_tablesize / sizeof(u32));
310
311 /* Initialize DART with table base and enable it. */
312 base = ((unsigned long)dart_tablebase) >> DART_PAGE_SHIFT;
313 size = dart_tablesize >> DART_PAGE_SHIFT;
314 if (dart_is_u4) {
315 size &= DART_SIZE_U4_SIZE_MASK;
316 DART_OUT(DART_BASE_U4, base);
317 DART_OUT(DART_SIZE_U4, size);
318 DART_OUT(DART_CNTL, DART_CNTL_U4_ENABLE);
319 } else {
320 size &= DART_CNTL_U3_SIZE_MASK;
321 DART_OUT(DART_CNTL,
322 DART_CNTL_U3_ENABLE |
323 (base << DART_CNTL_U3_BASE_SHIFT) |
324 (size << DART_CNTL_U3_SIZE_SHIFT));
325 }
326
327 /* Invalidate DART to get rid of possible stale TLBs */
328 dart_tlb_invalidate_all();
329
330 printk(KERN_INFO "DART IOMMU initialized for %s type chipset\n",
331 dart_is_u4 ? "U4" : "U3");
332
333 return 0;
334 }
335
336 static struct iommu_table_ops iommu_dart_ops = {
337 .set = dart_build,
338 .clear = dart_free,
339 .flush = dart_flush,
340 };
341
iommu_table_dart_setup(void)342 static void iommu_table_dart_setup(void)
343 {
344 iommu_table_dart.it_busno = 0;
345 iommu_table_dart.it_offset = 0;
346 /* it_size is in number of entries */
347 iommu_table_dart.it_size = dart_tablesize / sizeof(u32);
348 iommu_table_dart.it_page_shift = IOMMU_PAGE_SHIFT_4K;
349
350 /* Initialize the common IOMMU code */
351 iommu_table_dart.it_base = (unsigned long)dart_tablebase;
352 iommu_table_dart.it_index = 0;
353 iommu_table_dart.it_blocksize = 1;
354 iommu_table_dart.it_ops = &iommu_dart_ops;
355 iommu_init_table(&iommu_table_dart, -1);
356
357 /* Reserve the last page of the DART to avoid possible prefetch
358 * past the DART mapped area
359 */
360 set_bit(iommu_table_dart.it_size - 1, iommu_table_dart.it_map);
361 }
362
pci_dma_dev_setup_dart(struct pci_dev * dev)363 static void pci_dma_dev_setup_dart(struct pci_dev *dev)
364 {
365 if (dart_is_u4)
366 set_dma_offset(&dev->dev, DART_U4_BYPASS_BASE);
367 set_iommu_table_base(&dev->dev, &iommu_table_dart);
368 }
369
pci_dma_bus_setup_dart(struct pci_bus * bus)370 static void pci_dma_bus_setup_dart(struct pci_bus *bus)
371 {
372 if (!iommu_table_dart_inited) {
373 iommu_table_dart_inited = 1;
374 iommu_table_dart_setup();
375 }
376 }
377
dart_device_on_pcie(struct device * dev)378 static bool dart_device_on_pcie(struct device *dev)
379 {
380 struct device_node *np = of_node_get(dev->of_node);
381
382 while(np) {
383 if (of_device_is_compatible(np, "U4-pcie") ||
384 of_device_is_compatible(np, "u4-pcie")) {
385 of_node_put(np);
386 return true;
387 }
388 np = of_get_next_parent(np);
389 }
390 return false;
391 }
392
dart_dma_set_mask(struct device * dev,u64 dma_mask)393 static int dart_dma_set_mask(struct device *dev, u64 dma_mask)
394 {
395 if (!dev->dma_mask || !dma_supported(dev, dma_mask))
396 return -EIO;
397
398 /* U4 supports a DART bypass, we use it for 64-bit capable
399 * devices to improve performances. However, that only works
400 * for devices connected to U4 own PCIe interface, not bridged
401 * through hypertransport. We need the device to support at
402 * least 40 bits of addresses.
403 */
404 if (dart_device_on_pcie(dev) && dma_mask >= DMA_BIT_MASK(40)) {
405 dev_info(dev, "Using 64-bit DMA iommu bypass\n");
406 set_dma_ops(dev, &dma_nommu_ops);
407 } else {
408 dev_info(dev, "Using 32-bit DMA via iommu\n");
409 set_dma_ops(dev, &dma_iommu_ops);
410 }
411
412 *dev->dma_mask = dma_mask;
413 return 0;
414 }
415
iommu_init_early_dart(struct pci_controller_ops * controller_ops)416 void __init iommu_init_early_dart(struct pci_controller_ops *controller_ops)
417 {
418 struct device_node *dn;
419
420 /* Find the DART in the device-tree */
421 dn = of_find_compatible_node(NULL, "dart", "u3-dart");
422 if (dn == NULL) {
423 dn = of_find_compatible_node(NULL, "dart", "u4-dart");
424 if (dn == NULL)
425 return; /* use default direct_dma_ops */
426 dart_is_u4 = 1;
427 }
428
429 /* Initialize the DART HW */
430 if (dart_init(dn) != 0)
431 goto bail;
432
433 /* Setup bypass if supported */
434 if (dart_is_u4)
435 ppc_md.dma_set_mask = dart_dma_set_mask;
436
437 controller_ops->dma_dev_setup = pci_dma_dev_setup_dart;
438 controller_ops->dma_bus_setup = pci_dma_bus_setup_dart;
439
440 /* Setup pci_dma ops */
441 set_pci_dma_ops(&dma_iommu_ops);
442 return;
443
444 bail:
445 /* If init failed, use direct iommu and null setup functions */
446 controller_ops->dma_dev_setup = NULL;
447 controller_ops->dma_bus_setup = NULL;
448
449 /* Setup pci_dma ops */
450 set_pci_dma_ops(&dma_nommu_ops);
451 }
452
453 #ifdef CONFIG_PM
iommu_dart_restore(void)454 static void iommu_dart_restore(void)
455 {
456 dart_cache_sync(dart_tablebase, dart_tablesize / sizeof(u32));
457 dart_tlb_invalidate_all();
458 }
459
iommu_init_late_dart(void)460 static int __init iommu_init_late_dart(void)
461 {
462 if (!dart_tablebase)
463 return 0;
464
465 ppc_md.iommu_restore = iommu_dart_restore;
466
467 return 0;
468 }
469
470 late_initcall(iommu_init_late_dart);
471 #endif /* CONFIG_PM */
472
