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 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 /* 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);
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;
121 void __init pci_iommu_alloc(void)
124 /* free the range so iommu could get some range less than 4G */
125 dma32_free_bootmem();
127 if (pci_swiotlb_detect())
130 gart_iommu_hole_init();
134 detect_intel_iommu();
136 /* needs to be called after gart_iommu_hole_init */
142 void *dma_generic_alloc_coherent(struct device *dev, size_t size,
143 dma_addr_t *dma_addr, gfp_t flag)
145 unsigned long dma_mask;
149 dma_mask = dma_alloc_coherent_mask(dev, flag);
153 page = alloc_pages_node(dev_to_node(dev), flag, get_order(size));
157 addr = page_to_phys(page);
158 if (addr + size > dma_mask) {
159 __free_pages(page, get_order(size));
161 if (dma_mask < DMA_BIT_MASK(32) && !(flag & GFP_DMA)) {
162 flag = (flag & ~GFP_DMA32) | GFP_DMA;
170 return page_address(page);
174 * See <Documentation/x86_64/boot-options.txt> for the iommu kernel parameter
177 static __init int iommu_setup(char *p)
185 if (!strncmp(p, "off", 3))
187 /* gart_parse_options has more force support */
188 if (!strncmp(p, "force", 5))
190 if (!strncmp(p, "noforce", 7)) {
195 if (!strncmp(p, "biomerge", 8)) {
199 if (!strncmp(p, "panic", 5))
200 panic_on_overflow = 1;
201 if (!strncmp(p, "nopanic", 7))
202 panic_on_overflow = 0;
203 if (!strncmp(p, "merge", 5)) {
207 if (!strncmp(p, "nomerge", 7))
209 if (!strncmp(p, "forcesac", 8))
211 if (!strncmp(p, "allowdac", 8))
213 if (!strncmp(p, "nodac", 5))
215 if (!strncmp(p, "usedac", 6)) {
219 #ifdef CONFIG_SWIOTLB
220 if (!strncmp(p, "soft", 4))
223 if (!strncmp(p, "pt", 2))
224 iommu_pass_through = 1;
226 gart_parse_options(p);
228 #ifdef CONFIG_CALGARY_IOMMU
229 if (!strncmp(p, "calgary", 7))
231 #endif /* CONFIG_CALGARY_IOMMU */
233 p += strcspn(p, ",");
239 early_param("iommu", iommu_setup);
241 int dma_supported(struct device *dev, u64 mask)
243 struct dma_map_ops *ops = get_dma_ops(dev);
246 if (mask > 0xffffffff && forbid_dac > 0) {
247 dev_info(dev, "PCI: Disallowing DAC for device\n");
252 if (ops->dma_supported)
253 return ops->dma_supported(dev, mask);
255 /* Copied from i386. Doesn't make much sense, because it will
256 only work for pci_alloc_coherent.
257 The caller just has to use GFP_DMA in this case. */
258 if (mask < DMA_BIT_MASK(24))
261 /* Tell the device to use SAC when IOMMU force is on. This
262 allows the driver to use cheaper accesses in some cases.
264 Problem with this is that if we overflow the IOMMU area and
265 return DAC as fallback address the device may not handle it
268 As a special case some controllers have a 39bit address
269 mode that is as efficient as 32bit (aic79xx). Don't force
270 SAC for these. Assume all masks <= 40 bits are of this
271 type. Normally this doesn't make any difference, but gives
272 more gentle handling of IOMMU overflow. */
273 if (iommu_sac_force && (mask >= DMA_BIT_MASK(40))) {
274 dev_info(dev, "Force SAC with mask %Lx\n", mask);
280 EXPORT_SYMBOL(dma_supported);
282 static int __init pci_iommu_init(void)
284 dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
287 dma_debug_add_bus(&pci_bus_type);
289 x86_init.iommu.iommu_init();
292 printk(KERN_INFO "PCI-DMA: "
293 "Using software bounce buffering for IO (SWIOTLB)\n");
294 swiotlb_print_info();
300 /* Must execute after PCI subsystem */
301 rootfs_initcall(pci_iommu_init);
304 /* Many VIA bridges seem to corrupt data for DAC. Disable it here */
306 static __devinit void via_no_dac(struct pci_dev *dev)
308 if ((dev->class >> 8) == PCI_CLASS_BRIDGE_PCI && forbid_dac == 0) {
309 dev_info(&dev->dev, "disabling DAC on VIA PCI bridge\n");
313 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_VIA, PCI_ANY_ID, via_no_dac);