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-rw-r--r--arch/x86/pci/i386.c409
1 files changed, 409 insertions, 0 deletions
diff --git a/arch/x86/pci/i386.c b/arch/x86/pci/i386.c
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+// 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, &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();
+}
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