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 = &nommu_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 wants 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 /* Dummy device used for NULL arguments (normally ISA). */
47 struct device x86_dma_fallback_dev = {
48 .init_name = "fallback device",
49 .coherent_dma_mask = ISA_DMA_BIT_MASK,
50 .dma_mask = &x86_dma_fallback_dev.coherent_dma_mask,
52 EXPORT_SYMBOL(x86_dma_fallback_dev);
54 /* Number of entries preallocated for DMA-API debugging */
55 #define PREALLOC_DMA_DEBUG_ENTRIES 32768
57 int dma_set_mask(struct device *dev, u64 mask)
59 if (!dev->dma_mask || !dma_supported(dev, mask))
62 *dev->dma_mask = mask;
66 EXPORT_SYMBOL(dma_set_mask);
68 #if defined(CONFIG_X86_64) && !defined(CONFIG_NUMA)
69 static __initdata void *dma32_bootmem_ptr;
70 static unsigned long dma32_bootmem_size __initdata = (128ULL<<20);
72 static int __init parse_dma32_size_opt(char *p)
76 dma32_bootmem_size = memparse(p, &p);
79 early_param("dma32_size", parse_dma32_size_opt);
81 void __init dma32_reserve_bootmem(void)
83 unsigned long size, align;
84 if (max_pfn <= MAX_DMA32_PFN)
88 * check aperture_64.c allocate_aperture() for reason about
92 size = roundup(dma32_bootmem_size, align);
93 dma32_bootmem_ptr = __alloc_bootmem_nopanic(size, align,
96 * Kmemleak should not scan this block as it may not be mapped via the
97 * kernel direct mapping.
99 kmemleak_ignore(dma32_bootmem_ptr);
100 if (dma32_bootmem_ptr)
101 dma32_bootmem_size = size;
103 dma32_bootmem_size = 0;
105 static void __init dma32_free_bootmem(void)
108 if (max_pfn <= MAX_DMA32_PFN)
111 if (!dma32_bootmem_ptr)
114 free_bootmem(__pa(dma32_bootmem_ptr), dma32_bootmem_size);
116 dma32_bootmem_ptr = NULL;
117 dma32_bootmem_size = 0;
120 void __init dma32_reserve_bootmem(void)
123 static void __init dma32_free_bootmem(void)
129 void __init pci_iommu_alloc(void)
131 /* free the range so iommu could get some range less than 4G */
132 dma32_free_bootmem();
134 if (pci_swiotlb_detect())
137 gart_iommu_hole_init();
141 detect_intel_iommu();
143 /* needs to be called after gart_iommu_hole_init */
149 void *dma_generic_alloc_coherent(struct device *dev, size_t size,
150 dma_addr_t *dma_addr, gfp_t flag)
152 unsigned long dma_mask;
156 dma_mask = dma_alloc_coherent_mask(dev, flag);
160 page = alloc_pages_node(dev_to_node(dev), flag, get_order(size));
164 addr = page_to_phys(page);
165 if (addr + size > dma_mask) {
166 __free_pages(page, get_order(size));
168 if (dma_mask < DMA_BIT_MASK(32) && !(flag & GFP_DMA)) {
169 flag = (flag & ~GFP_DMA32) | GFP_DMA;
177 return page_address(page);
181 * See <Documentation/x86_64/boot-options.txt> for the iommu kernel parameter
184 static __init int iommu_setup(char *p)
192 if (!strncmp(p, "off", 3))
194 /* gart_parse_options has more force support */
195 if (!strncmp(p, "force", 5))
197 if (!strncmp(p, "noforce", 7)) {
202 if (!strncmp(p, "biomerge", 8)) {
206 if (!strncmp(p, "panic", 5))
207 panic_on_overflow = 1;
208 if (!strncmp(p, "nopanic", 7))
209 panic_on_overflow = 0;
210 if (!strncmp(p, "merge", 5)) {
214 if (!strncmp(p, "nomerge", 7))
216 if (!strncmp(p, "forcesac", 8))
218 if (!strncmp(p, "allowdac", 8))
220 if (!strncmp(p, "nodac", 5))
222 if (!strncmp(p, "usedac", 6)) {
226 #ifdef CONFIG_SWIOTLB
227 if (!strncmp(p, "soft", 4))
230 if (!strncmp(p, "pt", 2))
231 iommu_pass_through = 1;
233 gart_parse_options(p);
235 #ifdef CONFIG_CALGARY_IOMMU
236 if (!strncmp(p, "calgary", 7))
238 #endif /* CONFIG_CALGARY_IOMMU */
240 p += strcspn(p, ",");
246 early_param("iommu", iommu_setup);
248 int dma_supported(struct device *dev, u64 mask)
250 struct dma_map_ops *ops = get_dma_ops(dev);
253 if (mask > 0xffffffff && forbid_dac > 0) {
254 dev_info(dev, "PCI: Disallowing DAC for device\n");
259 if (ops->dma_supported)
260 return ops->dma_supported(dev, mask);
262 /* Copied from i386. Doesn't make much sense, because it will
263 only work for pci_alloc_coherent.
264 The caller just has to use GFP_DMA in this case. */
265 if (mask < DMA_BIT_MASK(24))
268 /* Tell the device to use SAC when IOMMU force is on. This
269 allows the driver to use cheaper accesses in some cases.
271 Problem with this is that if we overflow the IOMMU area and
272 return DAC as fallback address the device may not handle it
275 As a special case some controllers have a 39bit address
276 mode that is as efficient as 32bit (aic79xx). Don't force
277 SAC for these. Assume all masks <= 40 bits are of this
278 type. Normally this doesn't make any difference, but gives
279 more gentle handling of IOMMU overflow. */
280 if (iommu_sac_force && (mask >= DMA_BIT_MASK(40))) {
281 dev_info(dev, "Force SAC with mask %Lx\n", mask);
287 EXPORT_SYMBOL(dma_supported);
289 static int __init pci_iommu_init(void)
291 dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
294 dma_debug_add_bus(&pci_bus_type);
296 x86_init.iommu.iommu_init();
299 printk(KERN_INFO "PCI-DMA: "
300 "Using software bounce buffering for IO (SWIOTLB)\n");
301 swiotlb_print_info();
307 /* Must execute after PCI subsystem */
308 rootfs_initcall(pci_iommu_init);
311 /* Many VIA bridges seem to corrupt data for DAC. Disable it here */
313 static __devinit void via_no_dac(struct pci_dev *dev)
315 if ((dev->class >> 8) == PCI_CLASS_BRIDGE_PCI && forbid_dac == 0) {
316 dev_info(&dev->dev, "disabling DAC on VIA PCI bridge\n");
320 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_VIA, PCI_ANY_ID, via_no_dac);