1 /* 2 * Low-Level PCI Access for i386 machines 3 * 4 * Copyright 1993, 1994 Drew Eckhardt 5 * Visionary Computing 6 * (Unix and Linux consulting and custom programming) 7 * Drew@Colorado.EDU 8 * +1 (303) 786-7975 9 * 10 * Drew's work was sponsored by: 11 * iX Multiuser Multitasking Magazine 12 * Hannover, Germany 13 * hm@ix.de 14 * 15 * Copyright 1997--2000 Martin Mares <mj@ucw.cz> 16 * 17 * For more information, please consult the following manuals (look at 18 * http://www.pcisig.com/ for how to get them): 19 * 20 * PCI BIOS Specification 21 * PCI Local Bus Specification 22 * PCI to PCI Bridge Specification 23 * PCI System Design Guide 24 * 25 */ 26 27 #include <linux/types.h> 28 #include <linux/kernel.h> 29 #include <linux/export.h> 30 #include <linux/pci.h> 31 #include <linux/init.h> 32 #include <linux/ioport.h> 33 #include <linux/errno.h> 34 #include <linux/bootmem.h> 35 36 #include <asm/pat.h> 37 #include <asm/e820/api.h> 38 #include <asm/pci_x86.h> 39 #include <asm/io_apic.h> 40 41 42 /* 43 * This list of dynamic mappings is for temporarily maintaining 44 * original BIOS BAR addresses for possible reinstatement. 45 */ 46 struct pcibios_fwaddrmap { 47 struct list_head list; 48 struct pci_dev *dev; 49 resource_size_t fw_addr[DEVICE_COUNT_RESOURCE]; 50 }; 51 52 static LIST_HEAD(pcibios_fwaddrmappings); 53 static DEFINE_SPINLOCK(pcibios_fwaddrmap_lock); 54 static bool pcibios_fw_addr_done; 55 56 /* Must be called with 'pcibios_fwaddrmap_lock' lock held. */ 57 static struct pcibios_fwaddrmap *pcibios_fwaddrmap_lookup(struct pci_dev *dev) 58 { 59 struct pcibios_fwaddrmap *map; 60 61 WARN_ON_SMP(!spin_is_locked(&pcibios_fwaddrmap_lock)); 62 63 list_for_each_entry(map, &pcibios_fwaddrmappings, list) 64 if (map->dev == dev) 65 return map; 66 67 return NULL; 68 } 69 70 static void 71 pcibios_save_fw_addr(struct pci_dev *dev, int idx, resource_size_t fw_addr) 72 { 73 unsigned long flags; 74 struct pcibios_fwaddrmap *map; 75 76 if (pcibios_fw_addr_done) 77 return; 78 79 spin_lock_irqsave(&pcibios_fwaddrmap_lock, flags); 80 map = pcibios_fwaddrmap_lookup(dev); 81 if (!map) { 82 spin_unlock_irqrestore(&pcibios_fwaddrmap_lock, flags); 83 map = kzalloc(sizeof(*map), GFP_KERNEL); 84 if (!map) 85 return; 86 87 map->dev = pci_dev_get(dev); 88 map->fw_addr[idx] = fw_addr; 89 INIT_LIST_HEAD(&map->list); 90 91 spin_lock_irqsave(&pcibios_fwaddrmap_lock, flags); 92 list_add_tail(&map->list, &pcibios_fwaddrmappings); 93 } else 94 map->fw_addr[idx] = fw_addr; 95 spin_unlock_irqrestore(&pcibios_fwaddrmap_lock, flags); 96 } 97 98 resource_size_t pcibios_retrieve_fw_addr(struct pci_dev *dev, int idx) 99 { 100 unsigned long flags; 101 struct pcibios_fwaddrmap *map; 102 resource_size_t fw_addr = 0; 103 104 if (pcibios_fw_addr_done) 105 return 0; 106 107 spin_lock_irqsave(&pcibios_fwaddrmap_lock, flags); 108 map = pcibios_fwaddrmap_lookup(dev); 109 if (map) 110 fw_addr = map->fw_addr[idx]; 111 spin_unlock_irqrestore(&pcibios_fwaddrmap_lock, flags); 112 113 return fw_addr; 114 } 115 116 static void __init pcibios_fw_addr_list_del(void) 117 { 118 unsigned long flags; 119 struct pcibios_fwaddrmap *entry, *next; 120 121 spin_lock_irqsave(&pcibios_fwaddrmap_lock, flags); 122 list_for_each_entry_safe(entry, next, &pcibios_fwaddrmappings, list) { 123 list_del(&entry->list); 124 pci_dev_put(entry->dev); 125 kfree(entry); 126 } 127 spin_unlock_irqrestore(&pcibios_fwaddrmap_lock, flags); 128 pcibios_fw_addr_done = true; 129 } 130 131 static int 132 skip_isa_ioresource_align(struct pci_dev *dev) { 133 134 if ((pci_probe & PCI_CAN_SKIP_ISA_ALIGN) && 135 !(dev->bus->bridge_ctl & PCI_BRIDGE_CTL_ISA)) 136 return 1; 137 return 0; 138 } 139 140 /* 141 * We need to avoid collisions with `mirrored' VGA ports 142 * and other strange ISA hardware, so we always want the 143 * addresses to be allocated in the 0x000-0x0ff region 144 * modulo 0x400. 145 * 146 * Why? Because some silly external IO cards only decode 147 * the low 10 bits of the IO address. The 0x00-0xff region 148 * is reserved for motherboard devices that decode all 16 149 * bits, so it's ok to allocate at, say, 0x2800-0x28ff, 150 * but we want to try to avoid allocating at 0x2900-0x2bff 151 * which might have be mirrored at 0x0100-0x03ff.. 152 */ 153 resource_size_t 154 pcibios_align_resource(void *data, const struct resource *res, 155 resource_size_t size, resource_size_t align) 156 { 157 struct pci_dev *dev = data; 158 resource_size_t start = res->start; 159 160 if (res->flags & IORESOURCE_IO) { 161 if (skip_isa_ioresource_align(dev)) 162 return start; 163 if (start & 0x300) 164 start = (start + 0x3ff) & ~0x3ff; 165 } else if (res->flags & IORESOURCE_MEM) { 166 /* The low 1MB range is reserved for ISA cards */ 167 if (start < BIOS_END) 168 start = BIOS_END; 169 } 170 return start; 171 } 172 EXPORT_SYMBOL(pcibios_align_resource); 173 174 /* 175 * Handle resources of PCI devices. If the world were perfect, we could 176 * just allocate all the resource regions and do nothing more. It isn't. 177 * On the other hand, we cannot just re-allocate all devices, as it would 178 * require us to know lots of host bridge internals. So we attempt to 179 * keep as much of the original configuration as possible, but tweak it 180 * when it's found to be wrong. 181 * 182 * Known BIOS problems we have to work around: 183 * - I/O or memory regions not configured 184 * - regions configured, but not enabled in the command register 185 * - bogus I/O addresses above 64K used 186 * - expansion ROMs left enabled (this may sound harmless, but given 187 * the fact the PCI specs explicitly allow address decoders to be 188 * shared between expansion ROMs and other resource regions, it's 189 * at least dangerous) 190 * - bad resource sizes or overlaps with other regions 191 * 192 * Our solution: 193 * (1) Allocate resources for all buses behind PCI-to-PCI bridges. 194 * This gives us fixed barriers on where we can allocate. 195 * (2) Allocate resources for all enabled devices. If there is 196 * a collision, just mark the resource as unallocated. Also 197 * disable expansion ROMs during this step. 198 * (3) Try to allocate resources for disabled devices. If the 199 * resources were assigned correctly, everything goes well, 200 * if they weren't, they won't disturb allocation of other 201 * resources. 202 * (4) Assign new addresses to resources which were either 203 * not configured at all or misconfigured. If explicitly 204 * requested by the user, configure expansion ROM address 205 * as well. 206 */ 207 208 static void pcibios_allocate_bridge_resources(struct pci_dev *dev) 209 { 210 int idx; 211 struct resource *r; 212 213 for (idx = PCI_BRIDGE_RESOURCES; idx < PCI_NUM_RESOURCES; idx++) { 214 r = &dev->resource[idx]; 215 if (!r->flags) 216 continue; 217 if (r->parent) /* Already allocated */ 218 continue; 219 if (!r->start || pci_claim_bridge_resource(dev, idx) < 0) { 220 /* 221 * Something is wrong with the region. 222 * Invalidate the resource to prevent 223 * child resource allocations in this 224 * range. 225 */ 226 r->start = r->end = 0; 227 r->flags = 0; 228 } 229 } 230 } 231 232 static void pcibios_allocate_bus_resources(struct pci_bus *bus) 233 { 234 struct pci_bus *child; 235 236 /* Depth-First Search on bus tree */ 237 if (bus->self) 238 pcibios_allocate_bridge_resources(bus->self); 239 list_for_each_entry(child, &bus->children, node) 240 pcibios_allocate_bus_resources(child); 241 } 242 243 struct pci_check_idx_range { 244 int start; 245 int end; 246 }; 247 248 static void pcibios_allocate_dev_resources(struct pci_dev *dev, int pass) 249 { 250 int idx, disabled, i; 251 u16 command; 252 struct resource *r; 253 254 struct pci_check_idx_range idx_range[] = { 255 { PCI_STD_RESOURCES, PCI_STD_RESOURCE_END }, 256 #ifdef CONFIG_PCI_IOV 257 { PCI_IOV_RESOURCES, PCI_IOV_RESOURCE_END }, 258 #endif 259 }; 260 261 pci_read_config_word(dev, PCI_COMMAND, &command); 262 for (i = 0; i < ARRAY_SIZE(idx_range); i++) 263 for (idx = idx_range[i].start; idx <= idx_range[i].end; idx++) { 264 r = &dev->resource[idx]; 265 if (r->parent) /* Already allocated */ 266 continue; 267 if (!r->start) /* Address not assigned at all */ 268 continue; 269 if (r->flags & IORESOURCE_IO) 270 disabled = !(command & PCI_COMMAND_IO); 271 else 272 disabled = !(command & PCI_COMMAND_MEMORY); 273 if (pass == disabled) { 274 dev_dbg(&dev->dev, 275 "BAR %d: reserving %pr (d=%d, p=%d)\n", 276 idx, r, disabled, pass); 277 if (pci_claim_resource(dev, idx) < 0) { 278 if (r->flags & IORESOURCE_PCI_FIXED) { 279 dev_info(&dev->dev, "BAR %d %pR is immovable\n", 280 idx, r); 281 } else { 282 /* We'll assign a new address later */ 283 pcibios_save_fw_addr(dev, 284 idx, r->start); 285 r->end -= r->start; 286 r->start = 0; 287 } 288 } 289 } 290 } 291 if (!pass) { 292 r = &dev->resource[PCI_ROM_RESOURCE]; 293 if (r->flags & IORESOURCE_ROM_ENABLE) { 294 /* Turn the ROM off, leave the resource region, 295 * but keep it unregistered. */ 296 u32 reg; 297 dev_dbg(&dev->dev, "disabling ROM %pR\n", r); 298 r->flags &= ~IORESOURCE_ROM_ENABLE; 299 pci_read_config_dword(dev, dev->rom_base_reg, ®); 300 pci_write_config_dword(dev, dev->rom_base_reg, 301 reg & ~PCI_ROM_ADDRESS_ENABLE); 302 } 303 } 304 } 305 306 static void pcibios_allocate_resources(struct pci_bus *bus, int pass) 307 { 308 struct pci_dev *dev; 309 struct pci_bus *child; 310 311 list_for_each_entry(dev, &bus->devices, bus_list) { 312 pcibios_allocate_dev_resources(dev, pass); 313 314 child = dev->subordinate; 315 if (child) 316 pcibios_allocate_resources(child, pass); 317 } 318 } 319 320 static void pcibios_allocate_dev_rom_resource(struct pci_dev *dev) 321 { 322 struct resource *r; 323 324 /* 325 * Try to use BIOS settings for ROMs, otherwise let 326 * pci_assign_unassigned_resources() allocate the new 327 * addresses. 328 */ 329 r = &dev->resource[PCI_ROM_RESOURCE]; 330 if (!r->flags || !r->start) 331 return; 332 if (r->parent) /* Already allocated */ 333 return; 334 335 if (pci_claim_resource(dev, PCI_ROM_RESOURCE) < 0) { 336 r->end -= r->start; 337 r->start = 0; 338 } 339 } 340 static void pcibios_allocate_rom_resources(struct pci_bus *bus) 341 { 342 struct pci_dev *dev; 343 struct pci_bus *child; 344 345 list_for_each_entry(dev, &bus->devices, bus_list) { 346 pcibios_allocate_dev_rom_resource(dev); 347 348 child = dev->subordinate; 349 if (child) 350 pcibios_allocate_rom_resources(child); 351 } 352 } 353 354 static int __init pcibios_assign_resources(void) 355 { 356 struct pci_bus *bus; 357 358 if (!(pci_probe & PCI_ASSIGN_ROMS)) 359 list_for_each_entry(bus, &pci_root_buses, node) 360 pcibios_allocate_rom_resources(bus); 361 362 pci_assign_unassigned_resources(); 363 pcibios_fw_addr_list_del(); 364 365 return 0; 366 } 367 368 /** 369 * called in fs_initcall (one below subsys_initcall), 370 * give a chance for motherboard reserve resources 371 */ 372 fs_initcall(pcibios_assign_resources); 373 374 void pcibios_resource_survey_bus(struct pci_bus *bus) 375 { 376 dev_printk(KERN_DEBUG, &bus->dev, "Allocating resources\n"); 377 378 pcibios_allocate_bus_resources(bus); 379 380 pcibios_allocate_resources(bus, 0); 381 pcibios_allocate_resources(bus, 1); 382 383 if (!(pci_probe & PCI_ASSIGN_ROMS)) 384 pcibios_allocate_rom_resources(bus); 385 } 386 387 void __init pcibios_resource_survey(void) 388 { 389 struct pci_bus *bus; 390 391 DBG("PCI: Allocating resources\n"); 392 393 list_for_each_entry(bus, &pci_root_buses, node) 394 pcibios_allocate_bus_resources(bus); 395 396 list_for_each_entry(bus, &pci_root_buses, node) 397 pcibios_allocate_resources(bus, 0); 398 list_for_each_entry(bus, &pci_root_buses, node) 399 pcibios_allocate_resources(bus, 1); 400 401 e820__reserve_resources_late(); 402 /* 403 * Insert the IO APIC resources after PCI initialization has 404 * occurred to handle IO APICS that are mapped in on a BAR in 405 * PCI space, but before trying to assign unassigned pci res. 406 */ 407 ioapic_insert_resources(); 408 } 409