PCI: Pull PCI 'latency timer' setup up into the core
[linux-3.10.git] / arch / mn10300 / unit-asb2305 / pci-asb2305.c
1 /* ASB2305 PCI resource stuff
2  *
3  * Copyright (C) 2001 Red Hat, Inc. All Rights Reserved.
4  * Written by David Howells (dhowells@redhat.com)
5  * - Derived from arch/i386/pci-i386.c
6  *   - Copyright 1997--2000 Martin Mares <mj@suse.cz>
7  *
8  * This program is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU General Public Licence
10  * as published by the Free Software Foundation; either version
11  * 2 of the Licence, or (at your option) any later version.
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 #include "pci-asb2305.h"
20
21 /*
22  * We need to avoid collisions with `mirrored' VGA ports
23  * and other strange ISA hardware, so we always want the
24  * addresses to be allocated in the 0x000-0x0ff region
25  * modulo 0x400.
26  *
27  * Why? Because some silly external IO cards only decode
28  * the low 10 bits of the IO address. The 0x00-0xff region
29  * is reserved for motherboard devices that decode all 16
30  * bits, so it's ok to allocate at, say, 0x2800-0x28ff,
31  * but we want to try to avoid allocating at 0x2900-0x2bff
32  * which might have be mirrored at 0x0100-0x03ff..
33  */
34 resource_size_t pcibios_align_resource(void *data, const struct resource *res,
35                                 resource_size_t size, resource_size_t align)
36 {
37         resource_size_t start = res->start;
38
39 #if 0
40         struct pci_dev *dev = data;
41
42         printk(KERN_DEBUG
43                "### PCIBIOS_ALIGN_RESOURCE(%s,,{%08lx-%08lx,%08lx},%lx)\n",
44                pci_name(dev),
45                res->start,
46                res->end,
47                res->flags,
48                size
49                );
50 #endif
51
52         if ((res->flags & IORESOURCE_IO) && (start & 0x300))
53                 start = (start + 0x3ff) & ~0x3ff;
54
55         return start;
56 }
57
58
59 /*
60  *  Handle resources of PCI devices.  If the world were perfect, we could
61  *  just allocate all the resource regions and do nothing more.  It isn't.
62  *  On the other hand, we cannot just re-allocate all devices, as it would
63  *  require us to know lots of host bridge internals.  So we attempt to
64  *  keep as much of the original configuration as possible, but tweak it
65  *  when it's found to be wrong.
66  *
67  *  Known BIOS problems we have to work around:
68  *      - I/O or memory regions not configured
69  *      - regions configured, but not enabled in the command register
70  *      - bogus I/O addresses above 64K used
71  *      - expansion ROMs left enabled (this may sound harmless, but given
72  *        the fact the PCI specs explicitly allow address decoders to be
73  *        shared between expansion ROMs and other resource regions, it's
74  *        at least dangerous)
75  *
76  *  Our solution:
77  *      (1) Allocate resources for all buses behind PCI-to-PCI bridges.
78  *          This gives us fixed barriers on where we can allocate.
79  *      (2) Allocate resources for all enabled devices.  If there is
80  *          a collision, just mark the resource as unallocated. Also
81  *          disable expansion ROMs during this step.
82  *      (3) Try to allocate resources for disabled devices.  If the
83  *          resources were assigned correctly, everything goes well,
84  *          if they weren't, they won't disturb allocation of other
85  *          resources.
86  *      (4) Assign new addresses to resources which were either
87  *          not configured at all or misconfigured.  If explicitly
88  *          requested by the user, configure expansion ROM address
89  *          as well.
90  */
91 static void __init pcibios_allocate_bus_resources(struct list_head *bus_list)
92 {
93         struct pci_bus *bus;
94         struct pci_dev *dev;
95         int idx;
96         struct resource *r;
97
98         /* Depth-First Search on bus tree */
99         list_for_each_entry(bus, bus_list, node) {
100                 dev = bus->self;
101                 if (dev) {
102                         for (idx = PCI_BRIDGE_RESOURCES;
103                              idx < PCI_NUM_RESOURCES;
104                              idx++) {
105                                 r = &dev->resource[idx];
106                                 if (!r->flags)
107                                         continue;
108                                 if (!r->start ||
109                                     pci_claim_resource(dev, idx) < 0) {
110                                         printk(KERN_ERR "PCI:"
111                                                " Cannot allocate resource"
112                                                " region %d of bridge %s\n",
113                                                idx, pci_name(dev));
114                                         /* Something is wrong with the region.
115                                          * Invalidate the resource to prevent
116                                          * child resource allocations in this
117                                          * range. */
118                                         r->start = r->end = 0;
119                                         r->flags = 0;
120                                 }
121                         }
122                 }
123                 pcibios_allocate_bus_resources(&bus->children);
124         }
125 }
126
127 static void __init pcibios_allocate_resources(int pass)
128 {
129         struct pci_dev *dev = NULL;
130         int idx, disabled;
131         u16 command;
132         struct resource *r;
133
134         for_each_pci_dev(dev) {
135                 pci_read_config_word(dev, PCI_COMMAND, &command);
136                 for (idx = 0; idx < 6; idx++) {
137                         r = &dev->resource[idx];
138                         if (r->parent)          /* Already allocated */
139                                 continue;
140                         if (!r->start)          /* Address not assigned */
141                                 continue;
142                         if (r->flags & IORESOURCE_IO)
143                                 disabled = !(command & PCI_COMMAND_IO);
144                         else
145                                 disabled = !(command & PCI_COMMAND_MEMORY);
146                         if (pass == disabled) {
147                                 DBG("PCI[%s]: Resource %08lx-%08lx"
148                                     " (f=%lx, d=%d, p=%d)\n",
149                                     pci_name(dev), r->start, r->end, r->flags,
150                                     disabled, pass);
151                                 if (pci_claim_resource(dev, idx) < 0) {
152                                         printk(KERN_ERR "PCI:"
153                                                " Cannot allocate resource"
154                                                " region %d of device %s\n",
155                                                idx, pci_name(dev));
156                                         /* We'll assign a new address later */
157                                         r->end -= r->start;
158                                         r->start = 0;
159                                 }
160                         }
161                 }
162                 if (!pass) {
163                         r = &dev->resource[PCI_ROM_RESOURCE];
164                         if (r->flags & IORESOURCE_ROM_ENABLE) {
165                                 /* Turn the ROM off, leave the resource region,
166                                  * but keep it unregistered. */
167                                 u32 reg;
168                                 DBG("PCI: Switching off ROM of %s\n",
169                                     pci_name(dev));
170                                 r->flags &= ~IORESOURCE_ROM_ENABLE;
171                                 pci_read_config_dword(
172                                         dev, dev->rom_base_reg, &reg);
173                                 pci_write_config_dword(
174                                         dev, dev->rom_base_reg,
175                                         reg & ~PCI_ROM_ADDRESS_ENABLE);
176                         }
177                 }
178         }
179 }
180
181 static int __init pcibios_assign_resources(void)
182 {
183         struct pci_dev *dev = NULL;
184         struct resource *r;
185
186         if (!(pci_probe & PCI_ASSIGN_ROMS)) {
187                 /* Try to use BIOS settings for ROMs, otherwise let
188                    pci_assign_unassigned_resources() allocate the new
189                    addresses. */
190                 for_each_pci_dev(dev) {
191                         r = &dev->resource[PCI_ROM_RESOURCE];
192                         if (!r->flags || !r->start)
193                                 continue;
194                         if (pci_claim_resource(dev, PCI_ROM_RESOURCE) < 0) {
195                                 r->end -= r->start;
196                                 r->start = 0;
197                         }
198                 }
199         }
200
201         pci_assign_unassigned_resources();
202
203         return 0;
204 }
205
206 fs_initcall(pcibios_assign_resources);
207
208 void __init pcibios_resource_survey(void)
209 {
210         DBG("PCI: Allocating resources\n");
211         pcibios_allocate_bus_resources(&pci_root_buses);
212         pcibios_allocate_resources(0);
213         pcibios_allocate_resources(1);
214 }
215
216 void pcibios_set_master(struct pci_dev *dev)
217 {
218         u8 lat;
219
220         pci_read_config_byte(dev, PCI_LATENCY_TIMER, &lat);
221
222         if (lat < 16)
223                 lat = (64 <= pcibios_max_latency) ? 64 : pcibios_max_latency;
224         else if (lat > pcibios_max_latency)
225                 lat = pcibios_max_latency;
226         else
227                 return;
228
229         pci_write_config_byte(dev, PCI_LATENCY_TIMER, lat);
230 }
231
232 int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma,
233                         enum pci_mmap_state mmap_state, int write_combine)
234 {
235         unsigned long prot;
236
237         /* Leave vm_pgoff as-is, the PCI space address is the physical
238          * address on this platform.
239          */
240         vma->vm_flags |= VM_LOCKED | VM_IO;
241
242         prot = pgprot_val(vma->vm_page_prot);
243         prot &= ~_PAGE_CACHE;
244         vma->vm_page_prot = __pgprot(prot);
245
246         /* Write-combine setting is ignored */
247         if (io_remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
248                                vma->vm_end - vma->vm_start,
249                                vma->vm_page_prot))
250                 return -EAGAIN;
251
252         return 0;
253 }