arch/powerpc/sysdev/dart_iommu.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * arch/powerpc/sysdev/dart_iommu.c
   4  *
   5  * Copyright (C) 2004 Olof Johansson <olof@lixom.net>, IBM Corporation
   6  * Copyright (C) 2005 Benjamin Herrenschmidt <benh@kernel.crashing.org>,
   7  *                    IBM Corporation
   8  *
   9  * Based on pSeries_iommu.c:
  10  * Copyright (C) 2001 Mike Corrigan & Dave Engebretsen, IBM Corporation
  11  * Copyright (C) 2004 Olof Johansson <olof@lixom.net>, IBM Corporation
  12  *
  13  * Dynamic DMA mapping support, Apple U3, U4 & IBM CPC925 "DART" iommu.
  14  */
  15
  16 #include <linux/init.h>
  17 #include <linux/types.h>
  18 #include <linux/mm.h>
  19 #include <linux/spinlock.h>
  20 #include <linux/string.h>
  21 #include <linux/pci.h>
  22 #include <linux/dma-mapping.h>
  23 #include <linux/vmalloc.h>
  24 #include <linux/suspend.h>
  25 #include <linux/memblock.h>
  26 #include <linux/gfp.h>
  27 #include <linux/kmemleak.h>
  28 #include <asm/io.h>
  29 #include <asm/prom.h>
  30 #include <asm/iommu.h>
  31 #include <asm/pci-bridge.h>
  32 #include <asm/machdep.h>
  33 #include <asm/cacheflush.h>
  34 #include <asm/ppc-pci.h>
  35
  36 #include "dart.h"
  37
  38 /* DART table address and size */
  39 static u32 *dart_tablebase;
  40 static unsigned long dart_tablesize;
  41
  42 /* Mapped base address for the dart */
  43 static unsigned int __iomem *dart;
  44
  45 /* Dummy val that entries are set to when unused */
  46 static unsigned int dart_emptyval;
  47
  48 static struct iommu_table iommu_table_dart;
  49 static int iommu_table_dart_inited;
  50 static int dart_dirty;
  51 static int dart_is_u4;
  52
  53 #define DART_U4_BYPASS_BASE     0x8000000000ull
  54
  55 #define DBG(...)
  56
  57 static DEFINE_SPINLOCK(invalidate_lock);
  58
  59 static inline void dart_tlb_invalidate_all(void)
  60 {
  61         unsigned long l = 0;
  62         unsigned int reg, inv_bit;
  63         unsigned long limit;
  64         unsigned long flags;
  65
  66         spin_lock_irqsave(&invalidate_lock, flags);
  67
  68         DBG("dart: flush\n");
  69
  70         /* To invalidate the DART, set the DARTCNTL_FLUSHTLB bit in the
  71          * control register and wait for it to clear.
  72          *
  73          * Gotcha: Sometimes, the DART won't detect that the bit gets
  74          * set. If so, clear it and set it again.
  75          */
  76
  77         limit = 0;
  78
  79         inv_bit = dart_is_u4 ? DART_CNTL_U4_FLUSHTLB : DART_CNTL_U3_FLUSHTLB;
  80 retry:
  81         l = 0;
  82         reg = DART_IN(DART_CNTL);
  83         reg |= inv_bit;
  84         DART_OUT(DART_CNTL, reg);
  85
  86         while ((DART_IN(DART_CNTL) & inv_bit) && l < (1L << limit))
  87                 l++;
  88         if (l == (1L << limit)) {
  89                 if (limit < 4) {
  90                         limit++;
  91                         reg = DART_IN(DART_CNTL);
  92                         reg &= ~inv_bit;
  93                         DART_OUT(DART_CNTL, reg);
  94                         goto retry;
  95                 } else
  96                         panic("DART: TLB did not flush after waiting a long "
  97                               "time. Buggy U3 ?");
  98         }
  99
 100         spin_unlock_irqrestore(&invalidate_lock, flags);
 101 }
 102
 103 static inline void dart_tlb_invalidate_one(unsigned long bus_rpn)
 104 {
 105         unsigned int reg;
 106         unsigned int l, limit;
 107         unsigned long flags;
 108
 109         spin_lock_irqsave(&invalidate_lock, flags);
 110
 111         reg = DART_CNTL_U4_ENABLE | DART_CNTL_U4_IONE |
 112                 (bus_rpn & DART_CNTL_U4_IONE_MASK);
 113         DART_OUT(DART_CNTL, reg);
 114
 115         limit = 0;
 116 wait_more:
 117         l = 0;
 118         while ((DART_IN(DART_CNTL) & DART_CNTL_U4_IONE) && l < (1L << limit)) {
 119                 rmb();
 120                 l++;
 121         }
 122
 123         if (l == (1L << limit)) {
 124                 if (limit < 4) {
 125                         limit++;
 126                         goto wait_more;
 127                 } else
 128                         panic("DART: TLB did not flush after waiting a long "
 129                               "time. Buggy U4 ?");
 130         }
 131
 132         spin_unlock_irqrestore(&invalidate_lock, flags);
 133 }
 134
 135 static void dart_cache_sync(unsigned int *base, unsigned int count)
 136 {
 137         /*
 138          * We add 1 to the number of entries to flush, following a
 139          * comment in Darwin indicating that the memory controller
 140          * can prefetch unmapped memory under some circumstances.
 141          */
 142         unsigned long start = (unsigned long)base;
 143         unsigned long end = start + (count + 1) * sizeof(unsigned int);
 144         unsigned int tmp;
 145
 146         /* Perform a standard cache flush */
 147         flush_inval_dcache_range(start, end);
 148
 149         /*
 150          * Perform the sequence described in the CPC925 manual to
 151          * ensure all the data gets to a point the cache incoherent
 152          * DART hardware will see.
 153          */
 154         asm volatile(" sync;"
 155                      " isync;"
 156                      " dcbf 0,%1;"
 157                      " sync;"
 158                      " isync;"
 159                      " lwz %0,0(%1);"
 160                      " isync" : "=r" (tmp) : "r" (end) : "memory");
 161 }
 162
 163 static void dart_flush(struct iommu_table *tbl)
 164 {
 165         mb();
 166         if (dart_dirty) {
 167                 dart_tlb_invalidate_all();
 168                 dart_dirty = 0;
 169         }
 170 }
 171
 172 static int dart_build(struct iommu_table *tbl, long index,
 173                        long npages, unsigned long uaddr,
 174                        enum dma_data_direction direction,
 175                        unsigned long attrs)
 176 {
 177         unsigned int *dp, *orig_dp;
 178         unsigned int rpn;
 179         long l;
 180
 181         DBG("dart: build at: %lx, %lx, addr: %x\n", index, npages, uaddr);
 182
 183         orig_dp = dp = ((unsigned int*)tbl->it_base) + index;
 184
 185         /* On U3, all memory is contiguous, so we can move this
 186          * out of the loop.
 187          */
 188         l = npages;
 189         while (l--) {
 190                 rpn = __pa(uaddr) >> DART_PAGE_SHIFT;
 191
 192                 *(dp++) = DARTMAP_VALID | (rpn & DARTMAP_RPNMASK);
 193
 194                 uaddr += DART_PAGE_SIZE;
 195         }
 196         dart_cache_sync(orig_dp, npages);
 197
 198         if (dart_is_u4) {
 199                 rpn = index;
 200                 while (npages--)
 201                         dart_tlb_invalidate_one(rpn++);
 202         } else {
 203                 dart_dirty = 1;
 204         }
 205         return 0;
 206 }
 207
 208
 209 static void dart_free(struct iommu_table *tbl, long index, long npages)
 210 {
 211         unsigned int *dp, *orig_dp;
 212         long orig_npages = npages;
 213
 214         /* We don't worry about flushing the TLB cache. The only drawback of
 215          * not doing it is that we won't catch buggy device drivers doing
 216          * bad DMAs, but then no 32-bit architecture ever does either.
 217          */
 218
 219         DBG("dart: free at: %lx, %lx\n", index, npages);
 220
 221         orig_dp = dp  = ((unsigned int *)tbl->it_base) + index;
 222
 223         while (npages--)
 224                 *(dp++) = dart_emptyval;
 225
 226         dart_cache_sync(orig_dp, orig_npages);
 227 }
 228
 229 static void allocate_dart(void)
 230 {
 231         unsigned long tmp;
 232
 233         /* 512 pages (2MB) is max DART tablesize. */
 234         dart_tablesize = 1UL << 21;
 235
 236         /*
 237          * 16MB (1 << 24) alignment. We allocate a full 16Mb chuck since we
 238          * will blow up an entire large page anyway in the kernel mapping.
 239          */
 240         dart_tablebase = memblock_alloc_try_nid_raw(SZ_16M, SZ_16M,
 241                                         MEMBLOCK_LOW_LIMIT, SZ_2G,
 242                                         NUMA_NO_NODE);
 243         if (!dart_tablebase)
 244                 panic("Failed to allocate 16MB below 2GB for DART table\n");
 245
 246         /* There is no point scanning the DART space for leaks*/
 247         kmemleak_no_scan((void *)dart_tablebase);
 248
 249         /* Allocate a spare page to map all invalid DART pages. We need to do
 250          * that to work around what looks like a problem with the HT bridge
 251          * prefetching into invalid pages and corrupting data
 252          */
 253         tmp = memblock_phys_alloc(DART_PAGE_SIZE, DART_PAGE_SIZE);
 254         if (!tmp)
 255                 panic("DART: table allocation failed\n");
 256
 257         dart_emptyval = DARTMAP_VALID | ((tmp >> DART_PAGE_SHIFT) &
 258                                          DARTMAP_RPNMASK);
 259
 260         printk(KERN_INFO "DART table allocated at: %p\n", dart_tablebase);
 261 }
 262
 263 static int __init dart_init(struct device_node *dart_node)
 264 {
 265         unsigned int i;
 266         unsigned long base, size;
 267         struct resource r;
 268
 269         /* IOMMU disabled by the user ? bail out */
 270         if (iommu_is_off)
 271                 return -ENODEV;
 272
 273         /*
 274          * Only use the DART if the machine has more than 1GB of RAM
 275          * or if requested with iommu=on on cmdline.
 276          *
 277          * 1GB of RAM is picked as limit because some default devices
 278          * (i.e. Airport Extreme) have 30 bit address range limits.
 279          */
 280
 281         if (!iommu_force_on && memblock_end_of_DRAM() <= 0x40000000ull)
 282                 return -ENODEV;
 283
 284         /* Get DART registers */
 285         if (of_address_to_resource(dart_node, 0, &r))
 286                 panic("DART: can't get register base ! ");
 287
 288         /* Map in DART registers */
 289         dart = ioremap(r.start, resource_size(&r));
 290         if (dart == NULL)
 291                 panic("DART: Cannot map registers!");
 292
 293         /* Allocate the DART and dummy page */
 294         allocate_dart();
 295
 296         /* Fill initial table */
 297         for (i = 0; i < dart_tablesize/4; i++)
 298                 dart_tablebase[i] = dart_emptyval;
 299
 300         /* Push to memory */
 301         dart_cache_sync(dart_tablebase, dart_tablesize / sizeof(u32));
 302
 303         /* Initialize DART with table base and enable it. */
 304         base = ((unsigned long)dart_tablebase) >> DART_PAGE_SHIFT;
 305         size = dart_tablesize >> DART_PAGE_SHIFT;
 306         if (dart_is_u4) {
 307                 size &= DART_SIZE_U4_SIZE_MASK;
 308                 DART_OUT(DART_BASE_U4, base);
 309                 DART_OUT(DART_SIZE_U4, size);
 310                 DART_OUT(DART_CNTL, DART_CNTL_U4_ENABLE);
 311         } else {
 312                 size &= DART_CNTL_U3_SIZE_MASK;
 313                 DART_OUT(DART_CNTL,
 314                          DART_CNTL_U3_ENABLE |
 315                          (base << DART_CNTL_U3_BASE_SHIFT) |
 316                          (size << DART_CNTL_U3_SIZE_SHIFT));
 317         }
 318
 319         /* Invalidate DART to get rid of possible stale TLBs */
 320         dart_tlb_invalidate_all();
 321
 322         printk(KERN_INFO "DART IOMMU initialized for %s type chipset\n",
 323                dart_is_u4 ? "U4" : "U3");
 324
 325         return 0;
 326 }
 327
 328 static struct iommu_table_ops iommu_dart_ops = {
 329         .set = dart_build,
 330         .clear = dart_free,
 331         .flush = dart_flush,
 332 };
 333
 334 static void iommu_table_dart_setup(void)
 335 {
 336         iommu_table_dart.it_busno = 0;
 337         iommu_table_dart.it_offset = 0;
 338         /* it_size is in number of entries */
 339         iommu_table_dart.it_size = dart_tablesize / sizeof(u32);
 340         iommu_table_dart.it_page_shift = IOMMU_PAGE_SHIFT_4K;
 341
 342         /* Initialize the common IOMMU code */
 343         iommu_table_dart.it_base = (unsigned long)dart_tablebase;
 344         iommu_table_dart.it_index = 0;
 345         iommu_table_dart.it_blocksize = 1;
 346         iommu_table_dart.it_ops = &iommu_dart_ops;
 347         iommu_init_table(&iommu_table_dart, -1);
 348
 349         /* Reserve the last page of the DART to avoid possible prefetch
 350          * past the DART mapped area
 351          */
 352         set_bit(iommu_table_dart.it_size - 1, iommu_table_dart.it_map);
 353 }
 354
 355 static void pci_dma_bus_setup_dart(struct pci_bus *bus)
 356 {
 357         if (!iommu_table_dart_inited) {
 358                 iommu_table_dart_inited = 1;
 359                 iommu_table_dart_setup();
 360         }
 361 }
 362
 363 static bool dart_device_on_pcie(struct device *dev)
 364 {
 365         struct device_node *np = of_node_get(dev->of_node);
 366
 367         while(np) {
 368                 if (of_device_is_compatible(np, "U4-pcie") ||
 369                     of_device_is_compatible(np, "u4-pcie")) {
 370                         of_node_put(np);
 371                         return true;
 372                 }
 373                 np = of_get_next_parent(np);
 374         }
 375         return false;
 376 }
 377
 378 static void pci_dma_dev_setup_dart(struct pci_dev *dev)
 379 {
 380         if (dart_is_u4 && dart_device_on_pcie(&dev->dev))
 381                 dev->dev.archdata.dma_offset = DART_U4_BYPASS_BASE;
 382         set_iommu_table_base(&dev->dev, &iommu_table_dart);
 383 }
 384
 385 static bool iommu_bypass_supported_dart(struct pci_dev *dev, u64 mask)
 386 {
 387         return dart_is_u4 &&
 388                 dart_device_on_pcie(&dev->dev) &&
 389                 mask >= DMA_BIT_MASK(40);
 390 }
 391
 392 void __init iommu_init_early_dart(struct pci_controller_ops *controller_ops)
 393 {
 394         struct device_node *dn;
 395
 396         /* Find the DART in the device-tree */
 397         dn = of_find_compatible_node(NULL, "dart", "u3-dart");
 398         if (dn == NULL) {
 399                 dn = of_find_compatible_node(NULL, "dart", "u4-dart");
 400                 if (dn == NULL)
 401                         return; /* use default direct_dma_ops */
 402                 dart_is_u4 = 1;
 403         }
 404
 405         /* Initialize the DART HW */
 406         if (dart_init(dn) != 0)
 407                 return;
 408
 409         /*
 410          * U4 supports a DART bypass, we use it for 64-bit capable devices to
 411          * improve performance.  However, that only works for devices connected
 412          * to the U4 own PCIe interface, not bridged through hypertransport.
 413          * We need the device to support at least 40 bits of addresses.
 414          */
 415         controller_ops->dma_dev_setup = pci_dma_dev_setup_dart;
 416         controller_ops->dma_bus_setup = pci_dma_bus_setup_dart;
 417         controller_ops->iommu_bypass_supported = iommu_bypass_supported_dart;
 418
 419         /* Setup pci_dma ops */
 420         set_pci_dma_ops(&dma_iommu_ops);
 421 }
 422
 423 #ifdef CONFIG_PM
 424 static void iommu_dart_restore(void)
 425 {
 426         dart_cache_sync(dart_tablebase, dart_tablesize / sizeof(u32));
 427         dart_tlb_invalidate_all();
 428 }
 429
 430 static int __init iommu_init_late_dart(void)
 431 {
 432         if (!dart_tablebase)
 433                 return 0;
 434
 435         ppc_md.iommu_restore = iommu_dart_restore;
 436
 437         return 0;
 438 }
 439
 440 late_initcall(iommu_init_late_dart);
 441 #endif /* CONFIG_PM */