1 #include <linux/dma-mapping.h>
2 #include <linux/dma-debug.h>
3 #include <linux/dmar.h>
4 #include <linux/bootmem.h>
6 #include <linux/kmemleak.h>
10 #include <asm/iommu.h>
12 #include <asm/calgary.h>
13 #include <asm/amd_iommu.h>
14 #include <asm/x86_init.h>
16 static int forbid_dac __read_mostly;
18 struct dma_map_ops *dma_ops;
19 EXPORT_SYMBOL(dma_ops);
21 static int iommu_sac_force __read_mostly;
23 #ifdef CONFIG_IOMMU_DEBUG
24 int panic_on_overflow __read_mostly = 1;
25 int force_iommu __read_mostly = 1;
27 int panic_on_overflow __read_mostly = 0;
28 int force_iommu __read_mostly = 0;
31 int iommu_merge __read_mostly = 0;
33 int no_iommu __read_mostly;
34 /* Set this to 1 if there is a HW IOMMU in the system */
35 int iommu_detected __read_mostly = 0;
38 * This variable becomes 1 if iommu=pt is passed on the kernel command line.
39 * If this variable is 1, IOMMU implementations do no DMA translation for
40 * devices and allow every device to access to whole physical memory. This is
41 * useful if a user want to use an IOMMU only for KVM device assignment to
42 * guests and not for driver dma translation.
44 int iommu_pass_through __read_mostly;
46 dma_addr_t bad_dma_address __read_mostly = 0;
47 EXPORT_SYMBOL(bad_dma_address);
49 /* Dummy device used for NULL arguments (normally ISA). Better would
50 be probably a smaller DMA mask, but this is bug-to-bug compatible
52 struct device x86_dma_fallback_dev = {
53 .init_name = "fallback device",
54 .coherent_dma_mask = DMA_BIT_MASK(32),
55 .dma_mask = &x86_dma_fallback_dev.coherent_dma_mask,
57 EXPORT_SYMBOL(x86_dma_fallback_dev);
59 /* Number of entries preallocated for DMA-API debugging */
60 #define PREALLOC_DMA_DEBUG_ENTRIES 32768
62 int dma_set_mask(struct device *dev, u64 mask)
64 if (!dev->dma_mask || !dma_supported(dev, mask))
67 *dev->dma_mask = mask;
71 EXPORT_SYMBOL(dma_set_mask);
74 static __initdata void *dma32_bootmem_ptr;
75 static unsigned long dma32_bootmem_size __initdata = (128ULL<<20);
77 static int __init parse_dma32_size_opt(char *p)
81 dma32_bootmem_size = memparse(p, &p);
84 early_param("dma32_size", parse_dma32_size_opt);
86 void __init dma32_reserve_bootmem(void)
88 unsigned long size, align;
89 if (max_pfn <= MAX_DMA32_PFN)
93 * check aperture_64.c allocate_aperture() for reason about
97 size = roundup(dma32_bootmem_size, align);
98 dma32_bootmem_ptr = __alloc_bootmem_nopanic(size, align,
101 * Kmemleak should not scan this block as it may not be mapped via the
102 * kernel direct mapping.
104 kmemleak_ignore(dma32_bootmem_ptr);
105 if (dma32_bootmem_ptr)
106 dma32_bootmem_size = size;
108 dma32_bootmem_size = 0;
110 static void __init dma32_free_bootmem(void)
113 if (max_pfn <= MAX_DMA32_PFN)
116 if (!dma32_bootmem_ptr)
119 free_bootmem(__pa(dma32_bootmem_ptr), dma32_bootmem_size);
121 dma32_bootmem_ptr = NULL;
122 dma32_bootmem_size = 0;
126 void __init pci_iommu_alloc(void)
129 /* free the range so iommu could get some range less than 4G */
130 dma32_free_bootmem();
132 dma_ops = &nommu_dma_ops;
134 if (pci_swiotlb_init())
137 gart_iommu_hole_init();
141 detect_intel_iommu();
143 /* needs to be called after gart_iommu_hole_init */
147 void *dma_generic_alloc_coherent(struct device *dev, size_t size,
148 dma_addr_t *dma_addr, gfp_t flag)
150 unsigned long dma_mask;
154 dma_mask = dma_alloc_coherent_mask(dev, flag);
158 page = alloc_pages_node(dev_to_node(dev), flag, get_order(size));
162 addr = page_to_phys(page);
163 if (addr + size > dma_mask) {
164 __free_pages(page, get_order(size));
166 if (dma_mask < DMA_BIT_MASK(32) && !(flag & GFP_DMA)) {
167 flag = (flag & ~GFP_DMA32) | GFP_DMA;
175 return page_address(page);
179 * See <Documentation/x86_64/boot-options.txt> for the iommu kernel parameter
182 static __init int iommu_setup(char *p)
190 if (!strncmp(p, "off", 3))
192 /* gart_parse_options has more force support */
193 if (!strncmp(p, "force", 5))
195 if (!strncmp(p, "noforce", 7)) {
200 if (!strncmp(p, "biomerge", 8)) {
204 if (!strncmp(p, "panic", 5))
205 panic_on_overflow = 1;
206 if (!strncmp(p, "nopanic", 7))
207 panic_on_overflow = 0;
208 if (!strncmp(p, "merge", 5)) {
212 if (!strncmp(p, "nomerge", 7))
214 if (!strncmp(p, "forcesac", 8))
216 if (!strncmp(p, "allowdac", 8))
218 if (!strncmp(p, "nodac", 5))
220 if (!strncmp(p, "usedac", 6)) {
224 #ifdef CONFIG_SWIOTLB
225 if (!strncmp(p, "soft", 4))
228 if (!strncmp(p, "pt", 2))
229 iommu_pass_through = 1;
231 gart_parse_options(p);
233 #ifdef CONFIG_CALGARY_IOMMU
234 if (!strncmp(p, "calgary", 7))
236 #endif /* CONFIG_CALGARY_IOMMU */
238 p += strcspn(p, ",");
244 early_param("iommu", iommu_setup);
246 int dma_supported(struct device *dev, u64 mask)
248 struct dma_map_ops *ops = get_dma_ops(dev);
251 if (mask > 0xffffffff && forbid_dac > 0) {
252 dev_info(dev, "PCI: Disallowing DAC for device\n");
257 if (ops->dma_supported)
258 return ops->dma_supported(dev, mask);
260 /* Copied from i386. Doesn't make much sense, because it will
261 only work for pci_alloc_coherent.
262 The caller just has to use GFP_DMA in this case. */
263 if (mask < DMA_BIT_MASK(24))
266 /* Tell the device to use SAC when IOMMU force is on. This
267 allows the driver to use cheaper accesses in some cases.
269 Problem with this is that if we overflow the IOMMU area and
270 return DAC as fallback address the device may not handle it
273 As a special case some controllers have a 39bit address
274 mode that is as efficient as 32bit (aic79xx). Don't force
275 SAC for these. Assume all masks <= 40 bits are of this
276 type. Normally this doesn't make any difference, but gives
277 more gentle handling of IOMMU overflow. */
278 if (iommu_sac_force && (mask >= DMA_BIT_MASK(40))) {
279 dev_info(dev, "Force SAC with mask %Lx\n", mask);
285 EXPORT_SYMBOL(dma_supported);
287 static int __init pci_iommu_init(void)
289 dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
292 dma_debug_add_bus(&pci_bus_type);
294 x86_init.iommu.iommu_init();
297 printk(KERN_INFO "PCI-DMA: "
298 "Using software bounce buffering for IO (SWIOTLB)\n");
299 swiotlb_print_info();
305 /* Must execute after PCI subsystem */
306 rootfs_initcall(pci_iommu_init);
309 /* Many VIA bridges seem to corrupt data for DAC. Disable it here */
311 static __devinit void via_no_dac(struct pci_dev *dev)
313 if ((dev->class >> 8) == PCI_CLASS_BRIDGE_PCI && forbid_dac == 0) {
314 dev_info(&dev->dev, "disabling DAC on VIA PCI bridge\n");
318 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_VIA, PCI_ANY_ID, via_no_dac);