/* * Low-Level PCI Access for i386 machines * * Copyright 1993, 1994 Drew Eckhardt * Visionary Computing * (Unix and Linux consulting and custom programming) * Drew@Colorado.EDU * +1 (303) 786-7975 * * Drew's work was sponsored by: * iX Multiuser Multitasking Magazine * Hannover, Germany * hm@ix.de * * Copyright 1997--2000 Martin Mares <mj@ucw.cz> * * For more information, please consult the following manuals (look at * http://www.pcisig.com/ for how to get them): * * PCI BIOS Specification * PCI Local Bus Specification * PCI to PCI Bridge Specification * PCI System Design Guide * */ #include <linux/types.h> #include <linux/kernel.h> #include <linux/pci.h> #include <linux/init.h> #include <linux/ioport.h> #include <linux/errno.h> #include <linux/bootmem.h> #include <asm/pat.h> #include <asm/e820.h> #include <asm/pci_x86.h> #include <asm/io_apic.h> static int skip_isa_ioresource_align(struct pci_dev *dev) { if ((pci_probe & PCI_CAN_SKIP_ISA_ALIGN) && !(dev->bus->bridge_ctl & PCI_BRIDGE_CTL_ISA)) return 1; return 0; } /* * We need to avoid collisions with `mirrored' VGA ports * and other strange ISA hardware, so we always want the * addresses to be allocated in the 0x000-0x0ff region * modulo 0x400. * * Why? Because some silly external IO cards only decode * the low 10 bits of the IO address. The 0x00-0xff region * is reserved for motherboard devices that decode all 16 * bits, so it's ok to allocate at, say, 0x2800-0x28ff, * but we want to try to avoid allocating at 0x2900-0x2bff * which might have be mirrored at 0x0100-0x03ff.. */ resource_size_t pcibios_align_resource(void *data, const struct resource *res, resource_size_t size, resource_size_t align) { struct pci_dev *dev = data; resource_size_t start = res->start; if (res->flags & IORESOURCE_IO) { if (skip_isa_ioresource_align(dev)) return start; if (start & 0x300) start = (start + 0x3ff) & ~0x3ff; } return start; } EXPORT_SYMBOL(pcibios_align_resource); /* * Handle resources of PCI devices. If the world were perfect, we could * just allocate all the resource regions and do nothing more. It isn't. * On the other hand, we cannot just re-allocate all devices, as it would * require us to know lots of host bridge internals. So we attempt to * keep as much of the original configuration as possible, but tweak it * when it's found to be wrong. * * Known BIOS problems we have to work around: * - I/O or memory regions not configured * - regions configured, but not enabled in the command register * - bogus I/O addresses above 64K used * - expansion ROMs left enabled (this may sound harmless, but given * the fact the PCI specs explicitly allow address decoders to be * shared between expansion ROMs and other resource regions, it's * at least dangerous) * * Our solution: * (1) Allocate resources for all buses behind PCI-to-PCI bridges. * This gives us fixed barriers on where we can allocate. * (2) Allocate resources for all enabled devices. If there is * a collision, just mark the resource as unallocated. Also * disable expansion ROMs during this step. * (3) Try to allocate resources for disabled devices. If the * resources were assigned correctly, everything goes well, * if they weren't, they won't disturb allocation of other * resources. * (4) Assign new addresses to resources which were either * not configured at all or misconfigured. If explicitly * requested by the user, configure expansion ROM address * as well. */ static void __init pcibios_allocate_bus_resources(struct list_head *bus_list) { struct pci_bus *bus; struct pci_dev *dev; int idx; struct resource *r; /* Depth-First Search on bus tree */ list_for_each_entry(bus, bus_list, node) { if ((dev = bus->self)) { for (idx = PCI_BRIDGE_RESOURCES; idx < PCI_NUM_RESOURCES; idx++) { r = &dev->resource[idx]; if (!r->flags) continue; if (!r->start || pci_claim_resource(dev, idx) < 0) { dev_info(&dev->dev, "can't reserve window %pR\n", r); /* * Something is wrong with the region. * Invalidate the resource to prevent * child resource allocations in this * range. */ r->flags = 0; } } } pcibios_allocate_bus_resources(&bus->children); } } struct pci_check_idx_range { int start; int end; }; static void __init pcibios_allocate_resources(int pass) { struct pci_dev *dev = NULL; int idx, disabled, i; u16 command; struct resource *r; struct pci_check_idx_range idx_range[] = { { PCI_STD_RESOURCES, PCI_STD_RESOURCE_END }, #ifdef CONFIG_PCI_IOV { PCI_IOV_RESOURCES, PCI_IOV_RESOURCE_END }, #endif }; for_each_pci_dev(dev) { pci_read_config_word(dev, PCI_COMMAND, &command); for (i = 0; i < ARRAY_SIZE(idx_range); i++) for (idx = idx_range[i].start; idx <= idx_range[i].end; idx++) { r = &dev->resource[idx]; if (r->parent) /* Already allocated */ continue; if (!r->start) /* Address not assigned at all */ continue; if (r->flags & IORESOURCE_IO) disabled = !(command & PCI_COMMAND_IO); else disabled = !(command & PCI_COMMAND_MEMORY); if (pass == disabled) { dev_dbg(&dev->dev, "BAR %d: reserving %pr (d=%d, p=%d)\n", idx, r, disabled, pass); if (pci_claim_resource(dev, idx) < 0) { dev_info(&dev->dev, "can't reserve %pR\n", r); /* We'll assign a new address later */ r->end -= r->start; r->start = 0; } } } if (!pass) { r = &dev->resource[PCI_ROM_RESOURCE]; if (r->flags & IORESOURCE_ROM_ENABLE) { /* Turn the ROM off, leave the resource region, * but keep it unregistered. */ u32 reg; dev_dbg(&dev->dev, "disabling ROM %pR\n", r); r->flags &= ~IORESOURCE_ROM_ENABLE; pci_read_config_dword(dev, dev->rom_base_reg, ®); pci_write_config_dword(dev, dev->rom_base_reg, reg & ~PCI_ROM_ADDRESS_ENABLE); } } } } static int __init pcibios_assign_resources(void) { struct pci_dev *dev = NULL; struct resource *r; if (!(pci_probe & PCI_ASSIGN_ROMS)) { /* * Try to use BIOS settings for ROMs, otherwise let * pci_assign_unassigned_resources() allocate the new * addresses. */ for_each_pci_dev(dev) { r = &dev->resource[PCI_ROM_RESOURCE]; if (!r->flags || !r->start) continue; if (pci_claim_resource(dev, PCI_ROM_RESOURCE) < 0) { r->end -= r->start; r->start = 0; } } } pci_assign_unassigned_resources(); return 0; } void __init pcibios_resource_survey(void) { DBG("PCI: Allocating resources\n"); pcibios_allocate_bus_resources(&pci_root_buses); pcibios_allocate_resources(0); pcibios_allocate_resources(1); e820_reserve_resources_late(); /* * Insert the IO APIC resources after PCI initialization has * occured to handle IO APICS that are mapped in on a BAR in * PCI space, but before trying to assign unassigned pci res. */ ioapic_insert_resources(); } /** * called in fs_initcall (one below subsys_initcall), * give a chance for motherboard reserve resources */ fs_initcall(pcibios_assign_resources); /* * If we set up a device for bus mastering, we need to check the latency * timer as certain crappy BIOSes forget to set it properly. */ unsigned int pcibios_max_latency = 255; void pcibios_set_master(struct pci_dev *dev) { u8 lat; pci_read_config_byte(dev, PCI_LATENCY_TIMER, &lat); if (lat < 16) lat = (64 <= pcibios_max_latency) ? 64 : pcibios_max_latency; else if (lat > pcibios_max_latency) lat = pcibios_max_latency; else return; dev_printk(KERN_DEBUG, &dev->dev, "setting latency timer to %d\n", lat); pci_write_config_byte(dev, PCI_LATENCY_TIMER, lat); } static const struct vm_operations_struct pci_mmap_ops = { .access = generic_access_phys, }; int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma, enum pci_mmap_state mmap_state, int write_combine) { unsigned long prot; /* I/O space cannot be accessed via normal processor loads and * stores on this platform. */ if (mmap_state == pci_mmap_io) return -EINVAL; prot = pgprot_val(vma->vm_page_prot); /* * Return error if pat is not enabled and write_combine is requested. * Caller can followup with UC MINUS request and add a WC mtrr if there * is a free mtrr slot. */ if (!pat_enabled && write_combine) return -EINVAL; if (pat_enabled && write_combine) prot |= _PAGE_CACHE_WC; else if (pat_enabled || boot_cpu_data.x86 > 3) /* * ioremap() and ioremap_nocache() defaults to UC MINUS for now. * To avoid attribute conflicts, request UC MINUS here * aswell. */ prot |= _PAGE_CACHE_UC_MINUS; vma->vm_page_prot = __pgprot(prot); if (io_remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff, vma->vm_end - vma->vm_start, vma->vm_page_prot)) return -EAGAIN; vma->vm_ops = &pci_mmap_ops; return 0; }