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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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/pci.h>
30#include <linux/init.h>
31#include <linux/ioport.h>
32#include <linux/errno.h>
33
34#include "pci.h"
35
36/*
37 * We need to avoid collisions with `mirrored' VGA ports
38 * and other strange ISA hardware, so we always want the
39 * addresses to be allocated in the 0x000-0x0ff region
40 * modulo 0x400.
41 *
42 * Why? Because some silly external IO cards only decode
43 * the low 10 bits of the IO address. The 0x00-0xff region
44 * is reserved for motherboard devices that decode all 16
45 * bits, so it's ok to allocate at, say, 0x2800-0x28ff,
46 * but we want to try to avoid allocating at 0x2900-0x2bff
47 * which might have be mirrored at 0x0100-0x03ff..
48 */
49void
50pcibios_align_resource(void *data, struct resource *res,
51 unsigned long size, unsigned long align)
52{
53 if (res->flags & IORESOURCE_IO) {
54 unsigned long start = res->start;
55
56 if (start & 0x300) {
57 start = (start + 0x3ff) & ~0x3ff;
58 res->start = start;
59 }
60 }
61}
62
63
64/*
65 * Handle resources of PCI devices. If the world were perfect, we could
66 * just allocate all the resource regions and do nothing more. It isn't.
67 * On the other hand, we cannot just re-allocate all devices, as it would
68 * require us to know lots of host bridge internals. So we attempt to
69 * keep as much of the original configuration as possible, but tweak it
70 * when it's found to be wrong.
71 *
72 * Known BIOS problems we have to work around:
73 * - I/O or memory regions not configured
74 * - regions configured, but not enabled in the command register
75 * - bogus I/O addresses above 64K used
76 * - expansion ROMs left enabled (this may sound harmless, but given
77 * the fact the PCI specs explicitly allow address decoders to be
78 * shared between expansion ROMs and other resource regions, it's
79 * at least dangerous)
80 *
81 * Our solution:
82 * (1) Allocate resources for all buses behind PCI-to-PCI bridges.
83 * This gives us fixed barriers on where we can allocate.
84 * (2) Allocate resources for all enabled devices. If there is
85 * a collision, just mark the resource as unallocated. Also
86 * disable expansion ROMs during this step.
87 * (3) Try to allocate resources for disabled devices. If the
88 * resources were assigned correctly, everything goes well,
89 * if they weren't, they won't disturb allocation of other
90 * resources.
91 * (4) Assign new addresses to resources which were either
92 * not configured at all or misconfigured. If explicitly
93 * requested by the user, configure expansion ROM address
94 * as well.
95 */
96
97static void __init pcibios_allocate_bus_resources(struct list_head *bus_list)
98{
99 struct pci_bus *bus;
100 struct pci_dev *dev;
101 int idx;
102 struct resource *r, *pr;
103
104 /* Depth-First Search on bus tree */
105 list_for_each_entry(bus, bus_list, node) {
106 if ((dev = bus->self)) {
107 for (idx = PCI_BRIDGE_RESOURCES; idx < PCI_NUM_RESOURCES; idx++) {
108 r = &dev->resource[idx];
Ivan Kokshaysky299de032005-06-15 18:59:27 +0400109 if (!r->flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110 continue;
111 pr = pci_find_parent_resource(dev, r);
Ivan Kokshaysky299de032005-06-15 18:59:27 +0400112 if (!r->start || !pr || request_resource(pr, r) < 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113 printk(KERN_ERR "PCI: Cannot allocate resource region %d of bridge %s\n", idx, pci_name(dev));
Ivan Kokshaysky299de032005-06-15 18:59:27 +0400114 /* Something is wrong with the region.
115 Invalidate the resource to prevent child
116 resource allocations in this range. */
117 r->flags = 0;
118 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 }
120 }
121 pcibios_allocate_bus_resources(&bus->children);
122 }
123}
124
125static void __init pcibios_allocate_resources(int pass)
126{
127 struct pci_dev *dev = NULL;
128 int idx, disabled;
129 u16 command;
130 struct resource *r, *pr;
131
132 for_each_pci_dev(dev) {
133 pci_read_config_word(dev, PCI_COMMAND, &command);
134 for(idx = 0; idx < 6; idx++) {
135 r = &dev->resource[idx];
136 if (r->parent) /* Already allocated */
137 continue;
138 if (!r->start) /* Address not assigned at all */
139 continue;
140 if (r->flags & IORESOURCE_IO)
141 disabled = !(command & PCI_COMMAND_IO);
142 else
143 disabled = !(command & PCI_COMMAND_MEMORY);
144 if (pass == disabled) {
145 DBG("PCI: Resource %08lx-%08lx (f=%lx, d=%d, p=%d)\n",
146 r->start, r->end, r->flags, disabled, pass);
147 pr = pci_find_parent_resource(dev, r);
148 if (!pr || request_resource(pr, r) < 0) {
149 printk(KERN_ERR "PCI: Cannot allocate resource region %d of device %s\n", idx, pci_name(dev));
150 /* We'll assign a new address later */
151 r->end -= r->start;
152 r->start = 0;
153 }
154 }
155 }
156 if (!pass) {
157 r = &dev->resource[PCI_ROM_RESOURCE];
158 if (r->flags & IORESOURCE_ROM_ENABLE) {
159 /* Turn the ROM off, leave the resource region, but keep it unregistered. */
160 u32 reg;
161 DBG("PCI: Switching off ROM of %s\n", pci_name(dev));
162 r->flags &= ~IORESOURCE_ROM_ENABLE;
163 pci_read_config_dword(dev, dev->rom_base_reg, &reg);
164 pci_write_config_dword(dev, dev->rom_base_reg, reg & ~PCI_ROM_ADDRESS_ENABLE);
165 }
166 }
167 }
168}
169
170static int __init pcibios_assign_resources(void)
171{
172 struct pci_dev *dev = NULL;
Ivan Kokshaysky81d4af12005-08-30 18:48:52 +0400173 struct resource *r, *pr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174
Ivan Kokshaysky81d4af12005-08-30 18:48:52 +0400175 if (!(pci_probe & PCI_ASSIGN_ROMS)) {
176 /* Try to use BIOS settings for ROMs, otherwise let
177 pci_assign_unassigned_resources() allocate the new
178 addresses. */
179 for_each_pci_dev(dev) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180 r = &dev->resource[PCI_ROM_RESOURCE];
Ivan Kokshaysky81d4af12005-08-30 18:48:52 +0400181 if (!r->flags || !r->start)
182 continue;
183 pr = pci_find_parent_resource(dev, r);
184 if (!pr || request_resource(pr, r) < 0) {
185 r->end -= r->start;
186 r->start = 0;
187 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188 }
189 }
Ivan Kokshaysky81d4af12005-08-30 18:48:52 +0400190
191 pci_assign_unassigned_resources();
192
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193 return 0;
194}
195
196void __init pcibios_resource_survey(void)
197{
198 DBG("PCI: Allocating resources\n");
199 pcibios_allocate_bus_resources(&pci_root_buses);
200 pcibios_allocate_resources(0);
201 pcibios_allocate_resources(1);
202}
203
204/**
205 * called in fs_initcall (one below subsys_initcall),
206 * give a chance for motherboard reserve resources
207 */
208fs_initcall(pcibios_assign_resources);
209
210int pcibios_enable_resources(struct pci_dev *dev, int mask)
211{
212 u16 cmd, old_cmd;
213 int idx;
214 struct resource *r;
215
216 pci_read_config_word(dev, PCI_COMMAND, &cmd);
217 old_cmd = cmd;
Ivan Kokshaysky299de032005-06-15 18:59:27 +0400218 for(idx = 0; idx < PCI_NUM_RESOURCES; idx++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219 /* Only set up the requested stuff */
220 if (!(mask & (1<<idx)))
221 continue;
222
223 r = &dev->resource[idx];
Rajesh Shahed6d14f2005-11-23 15:44:59 -0800224 if (!(r->flags & (IORESOURCE_IO | IORESOURCE_MEM)))
225 continue;
226 if ((idx == PCI_ROM_RESOURCE) &&
227 (!(r->flags & IORESOURCE_ROM_ENABLE)))
228 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229 if (!r->start && r->end) {
230 printk(KERN_ERR "PCI: Device %s not available because of resource collisions\n", pci_name(dev));
231 return -EINVAL;
232 }
233 if (r->flags & IORESOURCE_IO)
234 cmd |= PCI_COMMAND_IO;
235 if (r->flags & IORESOURCE_MEM)
236 cmd |= PCI_COMMAND_MEMORY;
237 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238 if (cmd != old_cmd) {
239 printk("PCI: Enabling device %s (%04x -> %04x)\n", pci_name(dev), old_cmd, cmd);
240 pci_write_config_word(dev, PCI_COMMAND, cmd);
241 }
242 return 0;
243}
244
Rajesh Shah53e4d302006-05-03 15:27:47 -0700245void pcibios_disable_resources(struct pci_dev *dev)
246{
247 u16 cmd;
248
249 pci_read_config_word(dev, PCI_COMMAND, &cmd);
250 cmd &= ~(PCI_COMMAND_IO | PCI_COMMAND_MEMORY);
251 pci_write_config_word(dev, PCI_COMMAND, cmd);
252}
253
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254/*
255 * If we set up a device for bus mastering, we need to check the latency
256 * timer as certain crappy BIOSes forget to set it properly.
257 */
258unsigned int pcibios_max_latency = 255;
259
260void pcibios_set_master(struct pci_dev *dev)
261{
262 u8 lat;
263 pci_read_config_byte(dev, PCI_LATENCY_TIMER, &lat);
264 if (lat < 16)
265 lat = (64 <= pcibios_max_latency) ? 64 : pcibios_max_latency;
266 else if (lat > pcibios_max_latency)
267 lat = pcibios_max_latency;
268 else
269 return;
270 printk(KERN_DEBUG "PCI: Setting latency timer of device %s to %d\n", pci_name(dev), lat);
271 pci_write_config_byte(dev, PCI_LATENCY_TIMER, lat);
272}
273
274int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma,
275 enum pci_mmap_state mmap_state, int write_combine)
276{
277 unsigned long prot;
278
279 /* I/O space cannot be accessed via normal processor loads and
280 * stores on this platform.
281 */
282 if (mmap_state == pci_mmap_io)
283 return -EINVAL;
284
285 /* Leave vm_pgoff as-is, the PCI space address is the physical
286 * address on this platform.
287 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288 prot = pgprot_val(vma->vm_page_prot);
289 if (boot_cpu_data.x86 > 3)
290 prot |= _PAGE_PCD | _PAGE_PWT;
291 vma->vm_page_prot = __pgprot(prot);
292
293 /* Write-combine setting is ignored, it is changed via the mtrr
294 * interfaces on this platform.
295 */
Michael S. Tsirkin346d3882005-07-31 11:51:45 +0300296 if (io_remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
297 vma->vm_end - vma->vm_start,
298 vma->vm_page_prot))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299 return -EAGAIN;
300
301 return 0;
302}