1/* pci-frv.c: low-level PCI access routines 2 * 3 * Copyright (C) 2003-5 Red Hat, Inc. All Rights Reserved. 4 * Written by David Howells (dhowells@redhat.com) 5 * - Derived from the i386 equivalent stuff 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License 9 * as published by the Free Software Foundation; either version 10 * 2 of the License, or (at your option) any later version. 11 */ 12 13#include <linux/types.h> 14#include <linux/kernel.h> 15#include <linux/pci.h> 16#include <linux/init.h> 17#include <linux/ioport.h> 18#include <linux/errno.h> 19 20#include "pci-frv.h" 21 22/* 23 * We need to avoid collisions with `mirrored' VGA ports 24 * and other strange ISA hardware, so we always want the 25 * addresses to be allocated in the 0x000-0x0ff region 26 * modulo 0x400. 27 * 28 * Why? Because some silly external IO cards only decode 29 * the low 10 bits of the IO address. The 0x00-0xff region 30 * is reserved for motherboard devices that decode all 16 31 * bits, so it's ok to allocate at, say, 0x2800-0x28ff, 32 * but we want to try to avoid allocating at 0x2900-0x2bff 33 * which might have be mirrored at 0x0100-0x03ff.. 34 */ 35resource_size_t 36pcibios_align_resource(void *data, const struct resource *res, 37 resource_size_t size, resource_size_t align) 38{ 39 resource_size_t start = res->start; 40 41 if ((res->flags & IORESOURCE_IO) && (start & 0x300)) 42 start = (start + 0x3ff) & ~0x3ff; 43 44 return start; 45} 46 47 48/* 49 * Handle resources of PCI devices. If the world were perfect, we could 50 * just allocate all the resource regions and do nothing more. It isn't. 51 * On the other hand, we cannot just re-allocate all devices, as it would 52 * require us to know lots of host bridge internals. So we attempt to 53 * keep as much of the original configuration as possible, but tweak it 54 * when it's found to be wrong. 55 * 56 * Known BIOS problems we have to work around: 57 * - I/O or memory regions not configured 58 * - regions configured, but not enabled in the command register 59 * - bogus I/O addresses above 64K used 60 * - expansion ROMs left enabled (this may sound harmless, but given 61 * the fact the PCI specs explicitly allow address decoders to be 62 * shared between expansion ROMs and other resource regions, it's 63 * at least dangerous) 64 * 65 * Our solution: 66 * (1) Allocate resources for all buses behind PCI-to-PCI bridges. 67 * This gives us fixed barriers on where we can allocate. 68 * (2) Allocate resources for all enabled devices. If there is 69 * a collision, just mark the resource as unallocated. Also 70 * disable expansion ROMs during this step. 71 * (3) Try to allocate resources for disabled devices. If the 72 * resources were assigned correctly, everything goes well, 73 * if they weren't, they won't disturb allocation of other 74 * resources. 75 * (4) Assign new addresses to resources which were either 76 * not configured at all or misconfigured. If explicitly 77 * requested by the user, configure expansion ROM address 78 * as well. 79 */ 80 81static void __init pcibios_allocate_bus_resources(struct list_head *bus_list) 82{ 83 struct list_head *ln; 84 struct pci_bus *bus; 85 struct pci_dev *dev; 86 int idx; 87 struct resource *r; 88 89 /* Depth-First Search on bus tree */ 90 for (ln=bus_list->next; ln != bus_list; ln=ln->next) { 91 bus = pci_bus_b(ln); 92 if ((dev = bus->self)) { 93 for (idx = PCI_BRIDGE_RESOURCES; idx < PCI_NUM_RESOURCES; idx++) { 94 r = &dev->resource[idx]; 95 if (!r->start) 96 continue; 97 pci_claim_resource(dev, idx); 98 } 99 } 100 pcibios_allocate_bus_resources(&bus->children); 101 } 102} 103 104static void __init pcibios_allocate_resources(int pass) 105{ 106 struct pci_dev *dev = NULL; 107 int idx, disabled; 108 u16 command; 109 struct resource *r; 110 111 for_each_pci_dev(dev) { 112 pci_read_config_word(dev, PCI_COMMAND, &command); 113 for(idx = 0; idx < 6; idx++) { 114 r = &dev->resource[idx]; 115 if (r->parent) /* Already allocated */ 116 continue; 117 if (!r->start) /* Address not assigned at all */ 118 continue; 119 if (r->flags & IORESOURCE_IO) 120 disabled = !(command & PCI_COMMAND_IO); 121 else 122 disabled = !(command & PCI_COMMAND_MEMORY); 123 if (pass == disabled) { 124 DBG("PCI: Resource %08lx-%08lx (f=%lx, d=%d, p=%d)\n", 125 r->start, r->end, r->flags, disabled, pass); 126 if (pci_claim_resource(dev, idx) < 0) { 127 /* We'll assign a new address later */ 128 r->end -= r->start; 129 r->start = 0; 130 } 131 } 132 } 133 if (!pass) { 134 r = &dev->resource[PCI_ROM_RESOURCE]; 135 if (r->flags & IORESOURCE_ROM_ENABLE) { 136 /* Turn the ROM off, leave the resource region, but keep it unregistered. */ 137 u32 reg; 138 DBG("PCI: Switching off ROM of %s\n", pci_name(dev)); 139 r->flags &= ~IORESOURCE_ROM_ENABLE; 140 pci_read_config_dword(dev, dev->rom_base_reg, ®); 141 pci_write_config_dword(dev, dev->rom_base_reg, reg & ~PCI_ROM_ADDRESS_ENABLE); 142 } 143 } 144 } 145} 146 147static void __init pcibios_assign_resources(void) 148{ 149 struct pci_dev *dev = NULL; 150 int idx; 151 struct resource *r; 152 153 for_each_pci_dev(dev) { 154 int class = dev->class >> 8; 155 156 /* Don't touch classless devices and host bridges */ 157 if (!class || class == PCI_CLASS_BRIDGE_HOST) 158 continue; 159 160 for(idx=0; idx<6; idx++) { 161 r = &dev->resource[idx]; 162 163 /* 164 * Don't touch IDE controllers and I/O ports of video cards! 165 */ 166 if ((class == PCI_CLASS_STORAGE_IDE && idx < 4) || 167 (class == PCI_CLASS_DISPLAY_VGA && (r->flags & IORESOURCE_IO))) 168 continue; 169 170 /* 171 * We shall assign a new address to this resource, either because 172 * the BIOS forgot to do so or because we have decided the old 173 * address was unusable for some reason. 174 */ 175 if (!r->start && r->end) 176 pci_assign_resource(dev, idx); 177 } 178 179 if (pci_probe & PCI_ASSIGN_ROMS) { 180 r = &dev->resource[PCI_ROM_RESOURCE]; 181 r->end -= r->start; 182 r->start = 0; 183 if (r->end) 184 pci_assign_resource(dev, PCI_ROM_RESOURCE); 185 } 186 } 187} 188 189void __init pcibios_resource_survey(void) 190{ 191 DBG("PCI: Allocating resources\n"); 192 pcibios_allocate_bus_resources(&pci_root_buses); 193 pcibios_allocate_resources(0); 194 pcibios_allocate_resources(1); 195 pcibios_assign_resources(); 196} 197