| /* |
| * Dynamic DMA mapping support for AMD Hammer. |
| * |
| * Use the integrated AGP GART in the Hammer northbridge as an IOMMU for PCI. |
| * This allows to use PCI devices that only support 32bit addresses on systems |
| * with more than 4GB. |
| * |
| * See Documentation/DMA-mapping.txt for the interface specification. |
| * |
| * Copyright 2002 Andi Kleen, SuSE Labs. |
| */ |
| |
| #include <linux/config.h> |
| #include <linux/types.h> |
| #include <linux/ctype.h> |
| #include <linux/agp_backend.h> |
| #include <linux/init.h> |
| #include <linux/mm.h> |
| #include <linux/string.h> |
| #include <linux/spinlock.h> |
| #include <linux/pci.h> |
| #include <linux/module.h> |
| #include <linux/topology.h> |
| #include <linux/interrupt.h> |
| #include <linux/bitops.h> |
| #include <asm/atomic.h> |
| #include <asm/io.h> |
| #include <asm/mtrr.h> |
| #include <asm/pgtable.h> |
| #include <asm/proto.h> |
| #include <asm/cacheflush.h> |
| #include <asm/kdebug.h> |
| #include <asm/swiotlb.h> |
| #include <asm/dma.h> |
| |
| unsigned long iommu_bus_base; /* GART remapping area (physical) */ |
| static unsigned long iommu_size; /* size of remapping area bytes */ |
| static unsigned long iommu_pages; /* .. and in pages */ |
| |
| u32 *iommu_gatt_base; /* Remapping table */ |
| |
| /* If this is disabled the IOMMU will use an optimized flushing strategy |
| of only flushing when an mapping is reused. With it true the GART is flushed |
| for every mapping. Problem is that doing the lazy flush seems to trigger |
| bugs with some popular PCI cards, in particular 3ware (but has been also |
| also seen with Qlogic at least). */ |
| int iommu_fullflush = 1; |
| |
| #define MAX_NB 8 |
| |
| /* Allocation bitmap for the remapping area */ |
| static DEFINE_SPINLOCK(iommu_bitmap_lock); |
| static unsigned long *iommu_gart_bitmap; /* guarded by iommu_bitmap_lock */ |
| |
| static u32 gart_unmapped_entry; |
| |
| #define GPTE_VALID 1 |
| #define GPTE_COHERENT 2 |
| #define GPTE_ENCODE(x) \ |
| (((x) & 0xfffff000) | (((x) >> 32) << 4) | GPTE_VALID | GPTE_COHERENT) |
| #define GPTE_DECODE(x) (((x) & 0xfffff000) | (((u64)(x) & 0xff0) << 28)) |
| |
| #define to_pages(addr,size) \ |
| (round_up(((addr) & ~PAGE_MASK) + (size), PAGE_SIZE) >> PAGE_SHIFT) |
| |
| #define for_all_nb(dev) \ |
| dev = NULL; \ |
| while ((dev = pci_get_device(PCI_VENDOR_ID_AMD, 0x1103, dev))!=NULL)\ |
| if (dev->bus->number == 0 && \ |
| (PCI_SLOT(dev->devfn) >= 24) && (PCI_SLOT(dev->devfn) <= 31)) |
| |
| static struct pci_dev *northbridges[MAX_NB]; |
| static u32 northbridge_flush_word[MAX_NB]; |
| |
| #define EMERGENCY_PAGES 32 /* = 128KB */ |
| |
| #ifdef CONFIG_AGP |
| #define AGPEXTERN extern |
| #else |
| #define AGPEXTERN |
| #endif |
| |
| /* backdoor interface to AGP driver */ |
| AGPEXTERN int agp_memory_reserved; |
| AGPEXTERN __u32 *agp_gatt_table; |
| |
| static unsigned long next_bit; /* protected by iommu_bitmap_lock */ |
| static int need_flush; /* global flush state. set for each gart wrap */ |
| |
| static unsigned long alloc_iommu(int size) |
| { |
| unsigned long offset, flags; |
| |
| spin_lock_irqsave(&iommu_bitmap_lock, flags); |
| offset = find_next_zero_string(iommu_gart_bitmap,next_bit,iommu_pages,size); |
| if (offset == -1) { |
| need_flush = 1; |
| offset = find_next_zero_string(iommu_gart_bitmap,0,next_bit,size); |
| } |
| if (offset != -1) { |
| set_bit_string(iommu_gart_bitmap, offset, size); |
| next_bit = offset+size; |
| if (next_bit >= iommu_pages) { |
| next_bit = 0; |
| need_flush = 1; |
| } |
| } |
| if (iommu_fullflush) |
| need_flush = 1; |
| spin_unlock_irqrestore(&iommu_bitmap_lock, flags); |
| return offset; |
| } |
| |
| static void free_iommu(unsigned long offset, int size) |
| { |
| unsigned long flags; |
| spin_lock_irqsave(&iommu_bitmap_lock, flags); |
| __clear_bit_string(iommu_gart_bitmap, offset, size); |
| spin_unlock_irqrestore(&iommu_bitmap_lock, flags); |
| } |
| |
| /* |
| * Use global flush state to avoid races with multiple flushers. |
| */ |
| static void flush_gart(struct device *dev) |
| { |
| unsigned long flags; |
| int flushed = 0; |
| int i, max; |
| |
| spin_lock_irqsave(&iommu_bitmap_lock, flags); |
| if (need_flush) { |
| max = 0; |
| for (i = 0; i < MAX_NB; i++) { |
| if (!northbridges[i]) |
| continue; |
| pci_write_config_dword(northbridges[i], 0x9c, |
| northbridge_flush_word[i] | 1); |
| flushed++; |
| max = i; |
| } |
| for (i = 0; i <= max; i++) { |
| u32 w; |
| if (!northbridges[i]) |
| continue; |
| /* Make sure the hardware actually executed the flush. */ |
| do { |
| pci_read_config_dword(northbridges[i], 0x9c, &w); |
| } while (w & 1); |
| } |
| if (!flushed) |
| printk("nothing to flush?\n"); |
| need_flush = 0; |
| } |
| spin_unlock_irqrestore(&iommu_bitmap_lock, flags); |
| } |
| |
| |
| |
| #ifdef CONFIG_IOMMU_LEAK |
| |
| #define SET_LEAK(x) if (iommu_leak_tab) \ |
| iommu_leak_tab[x] = __builtin_return_address(0); |
| #define CLEAR_LEAK(x) if (iommu_leak_tab) \ |
| iommu_leak_tab[x] = NULL; |
| |
| /* Debugging aid for drivers that don't free their IOMMU tables */ |
| static void **iommu_leak_tab; |
| static int leak_trace; |
| int iommu_leak_pages = 20; |
| void dump_leak(void) |
| { |
| int i; |
| static int dump; |
| if (dump || !iommu_leak_tab) return; |
| dump = 1; |
| show_stack(NULL,NULL); |
| /* Very crude. dump some from the end of the table too */ |
| printk("Dumping %d pages from end of IOMMU:\n", iommu_leak_pages); |
| for (i = 0; i < iommu_leak_pages; i+=2) { |
| printk("%lu: ", iommu_pages-i); |
| printk_address((unsigned long) iommu_leak_tab[iommu_pages-i]); |
| printk("%c", (i+1)%2 == 0 ? '\n' : ' '); |
| } |
| printk("\n"); |
| } |
| #else |
| #define SET_LEAK(x) |
| #define CLEAR_LEAK(x) |
| #endif |
| |
| static void iommu_full(struct device *dev, size_t size, int dir) |
| { |
| /* |
| * Ran out of IOMMU space for this operation. This is very bad. |
| * Unfortunately the drivers cannot handle this operation properly. |
| * Return some non mapped prereserved space in the aperture and |
| * let the Northbridge deal with it. This will result in garbage |
| * in the IO operation. When the size exceeds the prereserved space |
| * memory corruption will occur or random memory will be DMAed |
| * out. Hopefully no network devices use single mappings that big. |
| */ |
| |
| printk(KERN_ERR |
| "PCI-DMA: Out of IOMMU space for %lu bytes at device %s\n", |
| size, dev->bus_id); |
| |
| if (size > PAGE_SIZE*EMERGENCY_PAGES) { |
| if (dir == PCI_DMA_FROMDEVICE || dir == PCI_DMA_BIDIRECTIONAL) |
| panic("PCI-DMA: Memory would be corrupted\n"); |
| if (dir == PCI_DMA_TODEVICE || dir == PCI_DMA_BIDIRECTIONAL) |
| panic(KERN_ERR "PCI-DMA: Random memory would be DMAed\n"); |
| } |
| |
| #ifdef CONFIG_IOMMU_LEAK |
| dump_leak(); |
| #endif |
| } |
| |
| static inline int need_iommu(struct device *dev, unsigned long addr, size_t size) |
| { |
| u64 mask = *dev->dma_mask; |
| int high = addr + size >= mask; |
| int mmu = high; |
| if (force_iommu) |
| mmu = 1; |
| return mmu; |
| } |
| |
| static inline int nonforced_iommu(struct device *dev, unsigned long addr, size_t size) |
| { |
| u64 mask = *dev->dma_mask; |
| int high = addr + size >= mask; |
| int mmu = high; |
| return mmu; |
| } |
| |
| /* Map a single continuous physical area into the IOMMU. |
| * Caller needs to check if the iommu is needed and flush. |
| */ |
| static dma_addr_t dma_map_area(struct device *dev, dma_addr_t phys_mem, |
| size_t size, int dir) |
| { |
| unsigned long npages = to_pages(phys_mem, size); |
| unsigned long iommu_page = alloc_iommu(npages); |
| int i; |
| if (iommu_page == -1) { |
| if (!nonforced_iommu(dev, phys_mem, size)) |
| return phys_mem; |
| if (panic_on_overflow) |
| panic("dma_map_area overflow %lu bytes\n", size); |
| iommu_full(dev, size, dir); |
| return bad_dma_address; |
| } |
| |
| for (i = 0; i < npages; i++) { |
| iommu_gatt_base[iommu_page + i] = GPTE_ENCODE(phys_mem); |
| SET_LEAK(iommu_page + i); |
| phys_mem += PAGE_SIZE; |
| } |
| return iommu_bus_base + iommu_page*PAGE_SIZE + (phys_mem & ~PAGE_MASK); |
| } |
| |
| static dma_addr_t gart_map_simple(struct device *dev, char *buf, |
| size_t size, int dir) |
| { |
| dma_addr_t map = dma_map_area(dev, virt_to_bus(buf), size, dir); |
| flush_gart(dev); |
| return map; |
| } |
| |
| /* Map a single area into the IOMMU */ |
| dma_addr_t gart_map_single(struct device *dev, void *addr, size_t size, int dir) |
| { |
| unsigned long phys_mem, bus; |
| |
| BUG_ON(dir == DMA_NONE); |
| |
| if (!dev) |
| dev = &fallback_dev; |
| |
| phys_mem = virt_to_phys(addr); |
| if (!need_iommu(dev, phys_mem, size)) |
| return phys_mem; |
| |
| bus = gart_map_simple(dev, addr, size, dir); |
| return bus; |
| } |
| |
| /* |
| * Wrapper for pci_unmap_single working with scatterlists. |
| */ |
| void gart_unmap_sg(struct device *dev, struct scatterlist *sg, int nents, int dir) |
| { |
| int i; |
| |
| for (i = 0; i < nents; i++) { |
| struct scatterlist *s = &sg[i]; |
| if (!s->dma_length || !s->length) |
| break; |
| dma_unmap_single(dev, s->dma_address, s->dma_length, dir); |
| } |
| } |
| |
| /* Fallback for dma_map_sg in case of overflow */ |
| static int dma_map_sg_nonforce(struct device *dev, struct scatterlist *sg, |
| int nents, int dir) |
| { |
| int i; |
| |
| #ifdef CONFIG_IOMMU_DEBUG |
| printk(KERN_DEBUG "dma_map_sg overflow\n"); |
| #endif |
| |
| for (i = 0; i < nents; i++ ) { |
| struct scatterlist *s = &sg[i]; |
| unsigned long addr = page_to_phys(s->page) + s->offset; |
| if (nonforced_iommu(dev, addr, s->length)) { |
| addr = dma_map_area(dev, addr, s->length, dir); |
| if (addr == bad_dma_address) { |
| if (i > 0) |
| gart_unmap_sg(dev, sg, i, dir); |
| nents = 0; |
| sg[0].dma_length = 0; |
| break; |
| } |
| } |
| s->dma_address = addr; |
| s->dma_length = s->length; |
| } |
| flush_gart(dev); |
| return nents; |
| } |
| |
| /* Map multiple scatterlist entries continuous into the first. */ |
| static int __dma_map_cont(struct scatterlist *sg, int start, int stopat, |
| struct scatterlist *sout, unsigned long pages) |
| { |
| unsigned long iommu_start = alloc_iommu(pages); |
| unsigned long iommu_page = iommu_start; |
| int i; |
| |
| if (iommu_start == -1) |
| return -1; |
| |
| for (i = start; i < stopat; i++) { |
| struct scatterlist *s = &sg[i]; |
| unsigned long pages, addr; |
| unsigned long phys_addr = s->dma_address; |
| |
| BUG_ON(i > start && s->offset); |
| if (i == start) { |
| *sout = *s; |
| sout->dma_address = iommu_bus_base; |
| sout->dma_address += iommu_page*PAGE_SIZE + s->offset; |
| sout->dma_length = s->length; |
| } else { |
| sout->dma_length += s->length; |
| } |
| |
| addr = phys_addr; |
| pages = to_pages(s->offset, s->length); |
| while (pages--) { |
| iommu_gatt_base[iommu_page] = GPTE_ENCODE(addr); |
| SET_LEAK(iommu_page); |
| addr += PAGE_SIZE; |
| iommu_page++; |
| } |
| } |
| BUG_ON(iommu_page - iommu_start != pages); |
| return 0; |
| } |
| |
| static inline int dma_map_cont(struct scatterlist *sg, int start, int stopat, |
| struct scatterlist *sout, |
| unsigned long pages, int need) |
| { |
| if (!need) { |
| BUG_ON(stopat - start != 1); |
| *sout = sg[start]; |
| sout->dma_length = sg[start].length; |
| return 0; |
| } |
| return __dma_map_cont(sg, start, stopat, sout, pages); |
| } |
| |
| /* |
| * DMA map all entries in a scatterlist. |
| * Merge chunks that have page aligned sizes into a continuous mapping. |
| */ |
| int gart_map_sg(struct device *dev, struct scatterlist *sg, int nents, int dir) |
| { |
| int i; |
| int out; |
| int start; |
| unsigned long pages = 0; |
| int need = 0, nextneed; |
| |
| BUG_ON(dir == DMA_NONE); |
| if (nents == 0) |
| return 0; |
| |
| if (!dev) |
| dev = &fallback_dev; |
| |
| out = 0; |
| start = 0; |
| for (i = 0; i < nents; i++) { |
| struct scatterlist *s = &sg[i]; |
| dma_addr_t addr = page_to_phys(s->page) + s->offset; |
| s->dma_address = addr; |
| BUG_ON(s->length == 0); |
| |
| nextneed = need_iommu(dev, addr, s->length); |
| |
| /* Handle the previous not yet processed entries */ |
| if (i > start) { |
| struct scatterlist *ps = &sg[i-1]; |
| /* Can only merge when the last chunk ends on a page |
| boundary and the new one doesn't have an offset. */ |
| if (!iommu_merge || !nextneed || !need || s->offset || |
| (ps->offset + ps->length) % PAGE_SIZE) { |
| if (dma_map_cont(sg, start, i, sg+out, pages, |
| need) < 0) |
| goto error; |
| out++; |
| pages = 0; |
| start = i; |
| } |
| } |
| |
| need = nextneed; |
| pages += to_pages(s->offset, s->length); |
| } |
| if (dma_map_cont(sg, start, i, sg+out, pages, need) < 0) |
| goto error; |
| out++; |
| flush_gart(dev); |
| if (out < nents) |
| sg[out].dma_length = 0; |
| return out; |
| |
| error: |
| flush_gart(NULL); |
| gart_unmap_sg(dev, sg, nents, dir); |
| /* When it was forced or merged try again in a dumb way */ |
| if (force_iommu || iommu_merge) { |
| out = dma_map_sg_nonforce(dev, sg, nents, dir); |
| if (out > 0) |
| return out; |
| } |
| if (panic_on_overflow) |
| panic("dma_map_sg: overflow on %lu pages\n", pages); |
| iommu_full(dev, pages << PAGE_SHIFT, dir); |
| for (i = 0; i < nents; i++) |
| sg[i].dma_address = bad_dma_address; |
| return 0; |
| } |
| |
| /* |
| * Free a DMA mapping. |
| */ |
| void gart_unmap_single(struct device *dev, dma_addr_t dma_addr, |
| size_t size, int direction) |
| { |
| unsigned long iommu_page; |
| int npages; |
| int i; |
| |
| if (dma_addr < iommu_bus_base + EMERGENCY_PAGES*PAGE_SIZE || |
| dma_addr >= iommu_bus_base + iommu_size) |
| return; |
| iommu_page = (dma_addr - iommu_bus_base)>>PAGE_SHIFT; |
| npages = to_pages(dma_addr, size); |
| for (i = 0; i < npages; i++) { |
| iommu_gatt_base[iommu_page + i] = gart_unmapped_entry; |
| CLEAR_LEAK(iommu_page + i); |
| } |
| free_iommu(iommu_page, npages); |
| } |
| |
| static int no_agp; |
| |
| static __init unsigned long check_iommu_size(unsigned long aper, u64 aper_size) |
| { |
| unsigned long a; |
| if (!iommu_size) { |
| iommu_size = aper_size; |
| if (!no_agp) |
| iommu_size /= 2; |
| } |
| |
| a = aper + iommu_size; |
| iommu_size -= round_up(a, LARGE_PAGE_SIZE) - a; |
| |
| if (iommu_size < 64*1024*1024) |
| printk(KERN_WARNING |
| "PCI-DMA: Warning: Small IOMMU %luMB. Consider increasing the AGP aperture in BIOS\n",iommu_size>>20); |
| |
| return iommu_size; |
| } |
| |
| static __init unsigned read_aperture(struct pci_dev *dev, u32 *size) |
| { |
| unsigned aper_size = 0, aper_base_32; |
| u64 aper_base; |
| unsigned aper_order; |
| |
| pci_read_config_dword(dev, 0x94, &aper_base_32); |
| pci_read_config_dword(dev, 0x90, &aper_order); |
| aper_order = (aper_order >> 1) & 7; |
| |
| aper_base = aper_base_32 & 0x7fff; |
| aper_base <<= 25; |
| |
| aper_size = (32 * 1024 * 1024) << aper_order; |
| if (aper_base + aper_size >= 0xffffffff || !aper_size) |
| aper_base = 0; |
| |
| *size = aper_size; |
| return aper_base; |
| } |
| |
| /* |
| * Private Northbridge GATT initialization in case we cannot use the |
| * AGP driver for some reason. |
| */ |
| static __init int init_k8_gatt(struct agp_kern_info *info) |
| { |
| struct pci_dev *dev; |
| void *gatt; |
| unsigned aper_base, new_aper_base; |
| unsigned aper_size, gatt_size, new_aper_size; |
| |
| printk(KERN_INFO "PCI-DMA: Disabling AGP.\n"); |
| aper_size = aper_base = info->aper_size = 0; |
| for_all_nb(dev) { |
| new_aper_base = read_aperture(dev, &new_aper_size); |
| if (!new_aper_base) |
| goto nommu; |
| |
| if (!aper_base) { |
| aper_size = new_aper_size; |
| aper_base = new_aper_base; |
| } |
| if (aper_size != new_aper_size || aper_base != new_aper_base) |
| goto nommu; |
| } |
| if (!aper_base) |
| goto nommu; |
| info->aper_base = aper_base; |
| info->aper_size = aper_size>>20; |
| |
| gatt_size = (aper_size >> PAGE_SHIFT) * sizeof(u32); |
| gatt = (void *)__get_free_pages(GFP_KERNEL, get_order(gatt_size)); |
| if (!gatt) |
| panic("Cannot allocate GATT table"); |
| memset(gatt, 0, gatt_size); |
| agp_gatt_table = gatt; |
| |
| for_all_nb(dev) { |
| u32 ctl; |
| u32 gatt_reg; |
| |
| gatt_reg = __pa(gatt) >> 12; |
| gatt_reg <<= 4; |
| pci_write_config_dword(dev, 0x98, gatt_reg); |
| pci_read_config_dword(dev, 0x90, &ctl); |
| |
| ctl |= 1; |
| ctl &= ~((1<<4) | (1<<5)); |
| |
| pci_write_config_dword(dev, 0x90, ctl); |
| } |
| flush_gart(NULL); |
| |
| printk("PCI-DMA: aperture base @ %x size %u KB\n",aper_base, aper_size>>10); |
| return 0; |
| |
| nommu: |
| /* Should not happen anymore */ |
| printk(KERN_ERR "PCI-DMA: More than 4GB of RAM and no IOMMU\n" |
| KERN_ERR "PCI-DMA: 32bit PCI IO may malfunction.\n"); |
| return -1; |
| } |
| |
| extern int agp_amd64_init(void); |
| |
| static struct dma_mapping_ops gart_dma_ops = { |
| .mapping_error = NULL, |
| .map_single = gart_map_single, |
| .map_simple = gart_map_simple, |
| .unmap_single = gart_unmap_single, |
| .sync_single_for_cpu = NULL, |
| .sync_single_for_device = NULL, |
| .sync_single_range_for_cpu = NULL, |
| .sync_single_range_for_device = NULL, |
| .sync_sg_for_cpu = NULL, |
| .sync_sg_for_device = NULL, |
| .map_sg = gart_map_sg, |
| .unmap_sg = gart_unmap_sg, |
| }; |
| |
| static int __init pci_iommu_init(void) |
| { |
| struct agp_kern_info info; |
| unsigned long aper_size; |
| unsigned long iommu_start; |
| struct pci_dev *dev; |
| unsigned long scratch; |
| long i; |
| |
| #ifndef CONFIG_AGP_AMD64 |
| no_agp = 1; |
| #else |
| /* Makefile puts PCI initialization via subsys_initcall first. */ |
| /* Add other K8 AGP bridge drivers here */ |
| no_agp = no_agp || |
| (agp_amd64_init() < 0) || |
| (agp_copy_info(agp_bridge, &info) < 0); |
| #endif |
| |
| if (swiotlb) |
| return -1; |
| |
| if (no_iommu || |
| (!force_iommu && end_pfn <= MAX_DMA32_PFN) || |
| !iommu_aperture || |
| (no_agp && init_k8_gatt(&info) < 0)) { |
| printk(KERN_INFO "PCI-DMA: Disabling IOMMU.\n"); |
| if (end_pfn > MAX_DMA32_PFN) { |
| printk(KERN_ERR "WARNING more than 4GB of memory " |
| "but IOMMU not compiled in.\n" |
| KERN_ERR "WARNING 32bit PCI may malfunction.\n" |
| KERN_ERR "You might want to enable " |
| "CONFIG_GART_IOMMU\n"); |
| } |
| return -1; |
| } |
| |
| printk(KERN_INFO "PCI-DMA: using GART IOMMU.\n"); |
| aper_size = info.aper_size * 1024 * 1024; |
| iommu_size = check_iommu_size(info.aper_base, aper_size); |
| iommu_pages = iommu_size >> PAGE_SHIFT; |
| |
| iommu_gart_bitmap = (void*)__get_free_pages(GFP_KERNEL, |
| get_order(iommu_pages/8)); |
| if (!iommu_gart_bitmap) |
| panic("Cannot allocate iommu bitmap\n"); |
| memset(iommu_gart_bitmap, 0, iommu_pages/8); |
| |
| #ifdef CONFIG_IOMMU_LEAK |
| if (leak_trace) { |
| iommu_leak_tab = (void *)__get_free_pages(GFP_KERNEL, |
| get_order(iommu_pages*sizeof(void *))); |
| if (iommu_leak_tab) |
| memset(iommu_leak_tab, 0, iommu_pages * 8); |
| else |
| printk("PCI-DMA: Cannot allocate leak trace area\n"); |
| } |
| #endif |
| |
| /* |
| * Out of IOMMU space handling. |
| * Reserve some invalid pages at the beginning of the GART. |
| */ |
| set_bit_string(iommu_gart_bitmap, 0, EMERGENCY_PAGES); |
| |
| agp_memory_reserved = iommu_size; |
| printk(KERN_INFO |
| "PCI-DMA: Reserving %luMB of IOMMU area in the AGP aperture\n", |
| iommu_size>>20); |
| |
| iommu_start = aper_size - iommu_size; |
| iommu_bus_base = info.aper_base + iommu_start; |
| bad_dma_address = iommu_bus_base; |
| iommu_gatt_base = agp_gatt_table + (iommu_start>>PAGE_SHIFT); |
| |
| /* |
| * Unmap the IOMMU part of the GART. The alias of the page is |
| * always mapped with cache enabled and there is no full cache |
| * coherency across the GART remapping. The unmapping avoids |
| * automatic prefetches from the CPU allocating cache lines in |
| * there. All CPU accesses are done via the direct mapping to |
| * the backing memory. The GART address is only used by PCI |
| * devices. |
| */ |
| clear_kernel_mapping((unsigned long)__va(iommu_bus_base), iommu_size); |
| |
| /* |
| * Try to workaround a bug (thanks to BenH) |
| * Set unmapped entries to a scratch page instead of 0. |
| * Any prefetches that hit unmapped entries won't get an bus abort |
| * then. |
| */ |
| scratch = get_zeroed_page(GFP_KERNEL); |
| if (!scratch) |
| panic("Cannot allocate iommu scratch page"); |
| gart_unmapped_entry = GPTE_ENCODE(__pa(scratch)); |
| for (i = EMERGENCY_PAGES; i < iommu_pages; i++) |
| iommu_gatt_base[i] = gart_unmapped_entry; |
| |
| for_all_nb(dev) { |
| u32 flag; |
| int cpu = PCI_SLOT(dev->devfn) - 24; |
| if (cpu >= MAX_NB) |
| continue; |
| northbridges[cpu] = dev; |
| pci_read_config_dword(dev, 0x9c, &flag); /* cache flush word */ |
| northbridge_flush_word[cpu] = flag; |
| } |
| |
| flush_gart(NULL); |
| |
| dma_ops = &gart_dma_ops; |
| |
| return 0; |
| } |
| |
| /* Must execute after PCI subsystem */ |
| fs_initcall(pci_iommu_init); |
| |
| void gart_parse_options(char *p) |
| { |
| int arg; |
| |
| #ifdef CONFIG_IOMMU_LEAK |
| if (!strncmp(p,"leak",4)) { |
| leak_trace = 1; |
| p += 4; |
| if (*p == '=') ++p; |
| if (isdigit(*p) && get_option(&p, &arg)) |
| iommu_leak_pages = arg; |
| } |
| #endif |
| if (isdigit(*p) && get_option(&p, &arg)) |
| iommu_size = arg; |
| if (!strncmp(p, "fullflush",8)) |
| iommu_fullflush = 1; |
| if (!strncmp(p, "nofullflush",11)) |
| iommu_fullflush = 0; |
| if (!strncmp(p,"noagp",5)) |
| no_agp = 1; |
| if (!strncmp(p, "noaperture",10)) |
| fix_aperture = 0; |
| /* duplicated from pci-dma.c */ |
| if (!strncmp(p,"force",5)) |
| iommu_aperture_allowed = 1; |
| if (!strncmp(p,"allowed",7)) |
| iommu_aperture_allowed = 1; |
| if (!strncmp(p, "memaper", 7)) { |
| fallback_aper_force = 1; |
| p += 7; |
| if (*p == '=') { |
| ++p; |
| if (get_option(&p, &arg)) |
| fallback_aper_order = arg; |
| } |
| } |
| } |