diff options
Diffstat (limited to 'arch/x86/pci/i386.c')
| -rw-r--r-- | arch/x86/pci/i386.c | 409 |
1 files changed, 409 insertions, 0 deletions
diff --git a/arch/x86/pci/i386.c b/arch/x86/pci/i386.c new file mode 100644 index 000000000..f2f4a5d50 --- /dev/null +++ b/arch/x86/pci/i386.c @@ -0,0 +1,409 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * 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/export.h> +#include <linux/pci.h> +#include <linux/init.h> +#include <linux/ioport.h> +#include <linux/errno.h> +#include <linux/memblock.h> + +#include <asm/memtype.h> +#include <asm/e820/api.h> +#include <asm/pci_x86.h> +#include <asm/io_apic.h> + + +/* + * This list of dynamic mappings is for temporarily maintaining + * original BIOS BAR addresses for possible reinstatement. + */ +struct pcibios_fwaddrmap { + struct list_head list; + struct pci_dev *dev; + resource_size_t fw_addr[DEVICE_COUNT_RESOURCE]; +}; + +static LIST_HEAD(pcibios_fwaddrmappings); +static DEFINE_SPINLOCK(pcibios_fwaddrmap_lock); +static bool pcibios_fw_addr_done; + +/* Must be called with 'pcibios_fwaddrmap_lock' lock held. */ +static struct pcibios_fwaddrmap *pcibios_fwaddrmap_lookup(struct pci_dev *dev) +{ + struct pcibios_fwaddrmap *map; + + lockdep_assert_held(&pcibios_fwaddrmap_lock); + + list_for_each_entry(map, &pcibios_fwaddrmappings, list) + if (map->dev == dev) + return map; + + return NULL; +} + +static void +pcibios_save_fw_addr(struct pci_dev *dev, int idx, resource_size_t fw_addr) +{ + unsigned long flags; + struct pcibios_fwaddrmap *map; + + if (pcibios_fw_addr_done) + return; + + spin_lock_irqsave(&pcibios_fwaddrmap_lock, flags); + map = pcibios_fwaddrmap_lookup(dev); + if (!map) { + spin_unlock_irqrestore(&pcibios_fwaddrmap_lock, flags); + map = kzalloc(sizeof(*map), GFP_KERNEL); + if (!map) + return; + + map->dev = pci_dev_get(dev); + map->fw_addr[idx] = fw_addr; + INIT_LIST_HEAD(&map->list); + + spin_lock_irqsave(&pcibios_fwaddrmap_lock, flags); + list_add_tail(&map->list, &pcibios_fwaddrmappings); + } else + map->fw_addr[idx] = fw_addr; + spin_unlock_irqrestore(&pcibios_fwaddrmap_lock, flags); +} + +resource_size_t pcibios_retrieve_fw_addr(struct pci_dev *dev, int idx) +{ + unsigned long flags; + struct pcibios_fwaddrmap *map; + resource_size_t fw_addr = 0; + + if (pcibios_fw_addr_done) + return 0; + + spin_lock_irqsave(&pcibios_fwaddrmap_lock, flags); + map = pcibios_fwaddrmap_lookup(dev); + if (map) + fw_addr = map->fw_addr[idx]; + spin_unlock_irqrestore(&pcibios_fwaddrmap_lock, flags); + + return fw_addr; +} + +static void __init pcibios_fw_addr_list_del(void) +{ + unsigned long flags; + struct pcibios_fwaddrmap *entry, *next; + + spin_lock_irqsave(&pcibios_fwaddrmap_lock, flags); + list_for_each_entry_safe(entry, next, &pcibios_fwaddrmappings, list) { + list_del(&entry->list); + pci_dev_put(entry->dev); + kfree(entry); + } + spin_unlock_irqrestore(&pcibios_fwaddrmap_lock, flags); + pcibios_fw_addr_done = true; +} + +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; + } else if (res->flags & IORESOURCE_MEM) { + /* The low 1MB range is reserved for ISA cards */ + if (start < BIOS_END) + start = BIOS_END; + } + 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) + * - bad resource sizes or overlaps with other regions + * + * 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 pcibios_allocate_bridge_resources(struct pci_dev *dev) +{ + int idx; + struct resource *r; + + for (idx = PCI_BRIDGE_RESOURCES; idx < PCI_NUM_RESOURCES; idx++) { + r = &dev->resource[idx]; + if (!r->flags) + continue; + if (r->parent) /* Already allocated */ + continue; + if (!r->start || pci_claim_bridge_resource(dev, idx) < 0) { + /* + * Something is wrong with the region. + * Invalidate the resource to prevent + * child resource allocations in this + * range. + */ + r->start = r->end = 0; + r->flags = 0; + } + } +} + +static void pcibios_allocate_bus_resources(struct pci_bus *bus) +{ + struct pci_bus *child; + + /* Depth-First Search on bus tree */ + if (bus->self) + pcibios_allocate_bridge_resources(bus->self); + list_for_each_entry(child, &bus->children, node) + pcibios_allocate_bus_resources(child); +} + +struct pci_check_idx_range { + int start; + int end; +}; + +static void pcibios_allocate_dev_resources(struct pci_dev *dev, int pass) +{ + 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 + }; + + 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) { + if (r->flags & IORESOURCE_PCI_FIXED) { + dev_info(&dev->dev, "BAR %d %pR is immovable\n", + idx, r); + } else { + /* We'll assign a new address later */ + pcibios_save_fw_addr(dev, + idx, r->start); + 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 void pcibios_allocate_resources(struct pci_bus *bus, int pass) +{ + struct pci_dev *dev; + struct pci_bus *child; + + list_for_each_entry(dev, &bus->devices, bus_list) { + pcibios_allocate_dev_resources(dev, pass); + + child = dev->subordinate; + if (child) + pcibios_allocate_resources(child, pass); + } +} + +static void pcibios_allocate_dev_rom_resource(struct pci_dev *dev) +{ + struct resource *r; + + /* + * Try to use BIOS settings for ROMs, otherwise let + * pci_assign_unassigned_resources() allocate the new + * addresses. + */ + r = &dev->resource[PCI_ROM_RESOURCE]; + if (!r->flags || !r->start) + return; + if (r->parent) /* Already allocated */ + return; + + if (pci_claim_resource(dev, PCI_ROM_RESOURCE) < 0) { + r->end -= r->start; + r->start = 0; + } +} +static void pcibios_allocate_rom_resources(struct pci_bus *bus) +{ + struct pci_dev *dev; + struct pci_bus *child; + + list_for_each_entry(dev, &bus->devices, bus_list) { + pcibios_allocate_dev_rom_resource(dev); + + child = dev->subordinate; + if (child) + pcibios_allocate_rom_resources(child); + } +} + +static int __init pcibios_assign_resources(void) +{ + struct pci_bus *bus; + + if (!(pci_probe & PCI_ASSIGN_ROMS)) + list_for_each_entry(bus, &pci_root_buses, node) + pcibios_allocate_rom_resources(bus); + + pci_assign_unassigned_resources(); + pcibios_fw_addr_list_del(); + + return 0; +} + +/* + * This is an fs_initcall (one below subsys_initcall) in order to reserve + * resources properly. + */ +fs_initcall(pcibios_assign_resources); + +void pcibios_resource_survey_bus(struct pci_bus *bus) +{ + dev_printk(KERN_DEBUG, &bus->dev, "Allocating resources\n"); + + pcibios_allocate_bus_resources(bus); + + pcibios_allocate_resources(bus, 0); + pcibios_allocate_resources(bus, 1); + + if (!(pci_probe & PCI_ASSIGN_ROMS)) + pcibios_allocate_rom_resources(bus); +} + +void __init pcibios_resource_survey(void) +{ + struct pci_bus *bus; + + DBG("PCI: Allocating resources\n"); + + list_for_each_entry(bus, &pci_root_buses, node) + pcibios_allocate_bus_resources(bus); + + list_for_each_entry(bus, &pci_root_buses, node) + pcibios_allocate_resources(bus, 0); + list_for_each_entry(bus, &pci_root_buses, node) + pcibios_allocate_resources(bus, 1); + + e820__reserve_resources_late(); + /* + * Insert the IO APIC resources after PCI initialization has + * occurred 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(); +} |