release/src-rt-6.x.4708/linux/linux-2.6.36/arch/x86/kernel/pci-dma.c

   1 #include <linux/dma-mapping.h>
   2 #include <linux/dma-debug.h>
   3 #include <linux/dmar.h>
   4 #include <linux/bootmem.h>
   5 #include <linux/gfp.h>
   6 #include <linux/pci.h>
   7 #include <linux/kmemleak.h>
   8
   9 #include <asm/proto.h>
  10 #include <asm/dma.h>
  11 #include <asm/iommu.h>
  12 #include <asm/gart.h>
  13 #include <asm/calgary.h>
  14 #include <asm/amd_iommu.h>
  15 #include <asm/x86_init.h>
  16 #include <asm/xen/swiotlb-xen.h>
  17
  18 static int forbid_dac __read_mostly;
  19
  20 struct dma_map_ops *dma_ops = &nommu_dma_ops;
  21 EXPORT_SYMBOL(dma_ops);
  22
  23 static int iommu_sac_force __read_mostly;
  24
  25 #ifdef CONFIG_IOMMU_DEBUG
  26 int panic_on_overflow __read_mostly = 1;
  27 int force_iommu __read_mostly = 1;
  28 #else
  29 int panic_on_overflow __read_mostly = 0;
  30 int force_iommu __read_mostly = 0;
  31 #endif
  32
  33 int iommu_merge __read_mostly = 0;
  34
  35 int no_iommu __read_mostly;
  36 /* Set this to 1 if there is a HW IOMMU in the system */
  37 int iommu_detected __read_mostly = 0;
  38
  39 /*
  40  * This variable becomes 1 if iommu=pt is passed on the kernel command line.
  41  * If this variable is 1, IOMMU implementations do no DMA translation for
  42  * devices and allow every device to access to whole physical memory. This is
  43  * useful if a user wants to use an IOMMU only for KVM device assignment to
  44  * guests and not for driver dma translation.
  45  */
  46 int iommu_pass_through __read_mostly;
  47
  48 /* Dummy device used for NULL arguments (normally ISA). */
  49 struct device x86_dma_fallback_dev = {
  50         .init_name = "fallback device",
  51         .coherent_dma_mask = ISA_DMA_BIT_MASK,
  52         .dma_mask = &x86_dma_fallback_dev.coherent_dma_mask,
  53 };
  54 EXPORT_SYMBOL(x86_dma_fallback_dev);
  55
  56 /* Number of entries preallocated for DMA-API debugging */
  57 #define PREALLOC_DMA_DEBUG_ENTRIES       32768
  58
  59 int dma_set_mask(struct device *dev, u64 mask)
  60 {
  61         if (!dev->dma_mask || !dma_supported(dev, mask))
  62                 return -EIO;
  63
  64         *dev->dma_mask = mask;
  65
  66         return 0;
  67 }
  68 EXPORT_SYMBOL(dma_set_mask);
  69
  70 #if defined(CONFIG_X86_64) && !defined(CONFIG_NUMA)
  71 static __initdata void *dma32_bootmem_ptr;
  72 static unsigned long dma32_bootmem_size __initdata = (128ULL<<20);
  73
  74 static int __init parse_dma32_size_opt(char *p)
  75 {
  76         if (!p)
  77                 return -EINVAL;
  78         dma32_bootmem_size = memparse(p, &p);
  79         return 0;
  80 }
  81 early_param("dma32_size", parse_dma32_size_opt);
  82
  83 void __init dma32_reserve_bootmem(void)
  84 {
  85         unsigned long size, align;
  86         if (max_pfn <= MAX_DMA32_PFN)
  87                 return;
  88
  89         /*
  90          * check aperture_64.c allocate_aperture() for reason about
  91          * using 512M as goal
  92          */
  93         align = 64ULL<<20;
  94         size = roundup(dma32_bootmem_size, align);
  95         dma32_bootmem_ptr = __alloc_bootmem_nopanic(size, align,
  96                                  512ULL<<20);
  97         /*
  98          * Kmemleak should not scan this block as it may not be mapped via the
  99          * kernel direct mapping.
 100          */
 101         kmemleak_ignore(dma32_bootmem_ptr);
 102         if (dma32_bootmem_ptr)
 103                 dma32_bootmem_size = size;
 104         else
 105                 dma32_bootmem_size = 0;
 106 }
 107 static void __init dma32_free_bootmem(void)
 108 {
 109
 110         if (max_pfn <= MAX_DMA32_PFN)
 111                 return;
 112
 113         if (!dma32_bootmem_ptr)
 114                 return;
 115
 116         free_bootmem(__pa(dma32_bootmem_ptr), dma32_bootmem_size);
 117
 118         dma32_bootmem_ptr = NULL;
 119         dma32_bootmem_size = 0;
 120 }
 121 #else
 122 void __init dma32_reserve_bootmem(void)
 123 {
 124 }
 125 static void __init dma32_free_bootmem(void)
 126 {
 127 }
 128
 129 #endif
 130
 131 void __init pci_iommu_alloc(void)
 132 {
 133         /* free the range so iommu could get some range less than 4G */
 134         dma32_free_bootmem();
 135
 136         if (pci_xen_swiotlb_detect() || pci_swiotlb_detect())
 137                 goto out;
 138
 139         gart_iommu_hole_init();
 140
 141         detect_calgary();
 142
 143         detect_intel_iommu();
 144
 145         /* needs to be called after gart_iommu_hole_init */
 146         amd_iommu_detect();
 147 out:
 148         pci_xen_swiotlb_init();
 149
 150         pci_swiotlb_init();
 151 }
 152
 153 void *dma_generic_alloc_coherent(struct device *dev, size_t size,
 154                                  dma_addr_t *dma_addr, gfp_t flag)
 155 {
 156         unsigned long dma_mask;
 157         struct page *page;
 158         dma_addr_t addr;
 159
 160         dma_mask = dma_alloc_coherent_mask(dev, flag);
 161
 162         flag |= __GFP_ZERO;
 163 again:
 164         page = alloc_pages_node(dev_to_node(dev), flag, get_order(size));
 165         if (!page)
 166                 return NULL;
 167
 168         addr = page_to_phys(page);
 169         if (addr + size > dma_mask) {
 170                 __free_pages(page, get_order(size));
 171
 172                 if (dma_mask < DMA_BIT_MASK(32) && !(flag & GFP_DMA)) {
 173                         flag = (flag & ~GFP_DMA32) | GFP_DMA;
 174                         goto again;
 175                 }
 176
 177                 return NULL;
 178         }
 179
 180         *dma_addr = addr;
 181         return page_address(page);
 182 }
 183
 184 /*
 185  * See <Documentation/x86_64/boot-options.txt> for the iommu kernel parameter
 186  * documentation.
 187  */
 188 static __init int iommu_setup(char *p)
 189 {
 190         iommu_merge = 1;
 191
 192         if (!p)
 193                 return -EINVAL;
 194
 195         while (*p) {
 196                 if (!strncmp(p, "off", 3))
 197                         no_iommu = 1;
 198                 /* gart_parse_options has more force support */
 199                 if (!strncmp(p, "force", 5))
 200                         force_iommu = 1;
 201                 if (!strncmp(p, "noforce", 7)) {
 202                         iommu_merge = 0;
 203                         force_iommu = 0;
 204                 }
 205
 206                 if (!strncmp(p, "biomerge", 8)) {
 207                         iommu_merge = 1;
 208                         force_iommu = 1;
 209                 }
 210                 if (!strncmp(p, "panic", 5))
 211                         panic_on_overflow = 1;
 212                 if (!strncmp(p, "nopanic", 7))
 213                         panic_on_overflow = 0;
 214                 if (!strncmp(p, "merge", 5)) {
 215                         iommu_merge = 1;
 216                         force_iommu = 1;
 217                 }
 218                 if (!strncmp(p, "nomerge", 7))
 219                         iommu_merge = 0;
 220                 if (!strncmp(p, "forcesac", 8))
 221                         iommu_sac_force = 1;
 222                 if (!strncmp(p, "allowdac", 8))
 223                         forbid_dac = 0;
 224                 if (!strncmp(p, "nodac", 5))
 225                         forbid_dac = 1;
 226                 if (!strncmp(p, "usedac", 6)) {
 227                         forbid_dac = -1;
 228                         return 1;
 229                 }
 230 #ifdef CONFIG_SWIOTLB
 231                 if (!strncmp(p, "soft", 4))
 232                         swiotlb = 1;
 233 #endif
 234                 if (!strncmp(p, "pt", 2))
 235                         iommu_pass_through = 1;
 236
 237                 gart_parse_options(p);
 238
 239 #ifdef CONFIG_CALGARY_IOMMU
 240                 if (!strncmp(p, "calgary", 7))
 241                         use_calgary = 1;
 242 #endif /* CONFIG_CALGARY_IOMMU */
 243
 244                 p += strcspn(p, ",");
 245                 if (*p == ',')
 246                         ++p;
 247         }
 248         return 0;
 249 }
 250 early_param("iommu", iommu_setup);
 251
 252 int dma_supported(struct device *dev, u64 mask)
 253 {
 254         struct dma_map_ops *ops = get_dma_ops(dev);
 255
 256 #ifdef CONFIG_PCI
 257         if (mask > 0xffffffff && forbid_dac > 0) {
 258                 dev_info(dev, "PCI: Disallowing DAC for device\n");
 259                 return 0;
 260         }
 261 #endif
 262
 263         if (ops->dma_supported)
 264                 return ops->dma_supported(dev, mask);
 265
 266         /* Copied from i386. Doesn't make much sense, because it will
 267            only work for pci_alloc_coherent.
 268            The caller just has to use GFP_DMA in this case. */
 269         if (mask < DMA_BIT_MASK(24))
 270                 return 0;
 271
 272         /* Tell the device to use SAC when IOMMU force is on.  This
 273            allows the driver to use cheaper accesses in some cases.
 274
 275            Problem with this is that if we overflow the IOMMU area and
 276            return DAC as fallback address the device may not handle it
 277            correctly.
 278
 279            As a special case some controllers have a 39bit address
 280            mode that is as efficient as 32bit (aic79xx). Don't force
 281            SAC for these.  Assume all masks <= 40 bits are of this
 282            type. Normally this doesn't make any difference, but gives
 283            more gentle handling of IOMMU overflow. */
 284         if (iommu_sac_force && (mask >= DMA_BIT_MASK(40))) {
 285                 dev_info(dev, "Force SAC with mask %Lx\n", mask);
 286                 return 0;
 287         }
 288
 289         return 1;
 290 }
 291 EXPORT_SYMBOL(dma_supported);
 292
 293 static int __init pci_iommu_init(void)
 294 {
 295         dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
 296
 297 #ifdef CONFIG_PCI
 298         dma_debug_add_bus(&pci_bus_type);
 299 #endif
 300         x86_init.iommu.iommu_init();
 301
 302         if (swiotlb || xen_swiotlb) {
 303                 printk(KERN_INFO "PCI-DMA: "
 304                        "Using software bounce buffering for IO (SWIOTLB)\n");
 305                 swiotlb_print_info();
 306         } else
 307                 swiotlb_free();
 308
 309         return 0;
 310 }
 311 /* Must execute after PCI subsystem */
 312 rootfs_initcall(pci_iommu_init);
 313
 314 #ifdef CONFIG_PCI
 315 /* Many VIA bridges seem to corrupt data for DAC. Disable it here */
 316
 317 static __devinit void via_no_dac(struct pci_dev *dev)
 318 {
 319         if ((dev->class >> 8) == PCI_CLASS_BRIDGE_PCI && forbid_dac == 0) {
 320                 dev_info(&dev->dev, "disabling DAC on VIA PCI bridge\n");
 321                 forbid_dac = 1;
 322         }
 323 }
 324 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_VIA, PCI_ANY_ID, via_no_dac);
 325 #endif