diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/i386/pci/i386.c |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'arch/i386/pci/i386.c')
-rw-r--r-- | arch/i386/pci/i386.c | 304 |
1 files changed, 304 insertions, 0 deletions
diff --git a/arch/i386/pci/i386.c b/arch/i386/pci/i386.c new file mode 100644 index 00000000000..c205ea7e233 --- /dev/null +++ b/arch/i386/pci/i386.c @@ -0,0 +1,304 @@ +/* + * 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 "pci.h" + +/* + * 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.. + */ +void +pcibios_align_resource(void *data, struct resource *res, + unsigned long size, unsigned long align) +{ + if (res->flags & IORESOURCE_IO) { + unsigned long start = res->start; + + if (start & 0x300) { + start = (start + 0x3ff) & ~0x3ff; + res->start = start; + } + } +} + + +/* + * 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, *pr; + + /* 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->start) + continue; + pr = pci_find_parent_resource(dev, r); + if (!pr || request_resource(pr, r) < 0) + printk(KERN_ERR "PCI: Cannot allocate resource region %d of bridge %s\n", idx, pci_name(dev)); + } + } + pcibios_allocate_bus_resources(&bus->children); + } +} + +static void __init pcibios_allocate_resources(int pass) +{ + struct pci_dev *dev = NULL; + int idx, disabled; + u16 command; + struct resource *r, *pr; + + for_each_pci_dev(dev) { + pci_read_config_word(dev, PCI_COMMAND, &command); + for(idx = 0; idx < 6; 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) { + DBG("PCI: Resource %08lx-%08lx (f=%lx, d=%d, p=%d)\n", + r->start, r->end, r->flags, disabled, pass); + pr = pci_find_parent_resource(dev, r); + if (!pr || request_resource(pr, r) < 0) { + printk(KERN_ERR "PCI: Cannot allocate resource region %d of device %s\n", idx, pci_name(dev)); + /* 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; + DBG("PCI: Switching off ROM of %s\n", pci_name(dev)); + 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; + int idx; + struct resource *r; + + for_each_pci_dev(dev) { + int class = dev->class >> 8; + + /* Don't touch classless devices and host bridges */ + if (!class || class == PCI_CLASS_BRIDGE_HOST) + continue; + + for(idx=0; idx<6; idx++) { + r = &dev->resource[idx]; + + /* + * Don't touch IDE controllers and I/O ports of video cards! + */ + if ((class == PCI_CLASS_STORAGE_IDE && idx < 4) || + (class == PCI_CLASS_DISPLAY_VGA && (r->flags & IORESOURCE_IO))) + continue; + + /* + * We shall assign a new address to this resource, either because + * the BIOS forgot to do so or because we have decided the old + * address was unusable for some reason. + */ + if (!r->start && r->end) + pci_assign_resource(dev, idx); + } + + if (pci_probe & PCI_ASSIGN_ROMS) { + r = &dev->resource[PCI_ROM_RESOURCE]; + r->end -= r->start; + r->start = 0; + if (r->end) + pci_assign_resource(dev, PCI_ROM_RESOURCE); + } + } + 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); +} + +/** + * called in fs_initcall (one below subsys_initcall), + * give a chance for motherboard reserve resources + */ +fs_initcall(pcibios_assign_resources); + +int pcibios_enable_resources(struct pci_dev *dev, int mask) +{ + u16 cmd, old_cmd; + int idx; + struct resource *r; + + pci_read_config_word(dev, PCI_COMMAND, &cmd); + old_cmd = cmd; + for(idx=0; idx<6; idx++) { + /* Only set up the requested stuff */ + if (!(mask & (1<<idx))) + continue; + + r = &dev->resource[idx]; + if (!r->start && r->end) { + printk(KERN_ERR "PCI: Device %s not available because of resource collisions\n", pci_name(dev)); + return -EINVAL; + } + if (r->flags & IORESOURCE_IO) + cmd |= PCI_COMMAND_IO; + if (r->flags & IORESOURCE_MEM) + cmd |= PCI_COMMAND_MEMORY; + } + if (dev->resource[PCI_ROM_RESOURCE].start) + cmd |= PCI_COMMAND_MEMORY; + if (cmd != old_cmd) { + printk("PCI: Enabling device %s (%04x -> %04x)\n", pci_name(dev), old_cmd, cmd); + pci_write_config_word(dev, PCI_COMMAND, cmd); + } + return 0; +} + +/* + * 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; + printk(KERN_DEBUG "PCI: Setting latency timer of device %s to %d\n", pci_name(dev), lat); + pci_write_config_byte(dev, PCI_LATENCY_TIMER, lat); +} + +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; + + /* Leave vm_pgoff as-is, the PCI space address is the physical + * address on this platform. + */ + vma->vm_flags |= (VM_SHM | VM_LOCKED | VM_IO); + + prot = pgprot_val(vma->vm_page_prot); + if (boot_cpu_data.x86 > 3) + prot |= _PAGE_PCD | _PAGE_PWT; + vma->vm_page_prot = __pgprot(prot); + + /* Write-combine setting is ignored, it is changed via the mtrr + * interfaces on this platform. + */ + if (remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff, + vma->vm_end - vma->vm_start, + vma->vm_page_prot)) + return -EAGAIN; + + return 0; +} |