1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Routines for tracking a legacy ISA bridge
4 *
5 * Copyrigh 2007 Benjamin Herrenschmidt <benh@kernel.crashing.org>, IBM Corp.
6 *
7 * Some bits and pieces moved over from pci_64.c
8 *
9 * Copyrigh 2003 Anton Blanchard <anton@au.ibm.com>, IBM Corp.
10 */
11
12 #define DEBUG
13
14 #include <linux/kernel.h>
15 #include <linux/pci.h>
16 #include <linux/string.h>
17 #include <linux/export.h>
18 #include <linux/init.h>
19 #include <linux/mm.h>
20 #include <linux/notifier.h>
21 #include <linux/of_address.h>
22 #include <linux/vmalloc.h>
23
24 #include <asm/processor.h>
25 #include <asm/io.h>
26 #include <asm/pci-bridge.h>
27 #include <asm/machdep.h>
28 #include <asm/ppc-pci.h>
29 #include <asm/isa-bridge.h>
30
31 unsigned long isa_io_base; /* NULL if no ISA bus */
32 EXPORT_SYMBOL(isa_io_base);
33
34 /* Cached ISA bridge dev. */
35 static struct device_node *isa_bridge_devnode;
36 struct pci_dev *isa_bridge_pcidev;
37 EXPORT_SYMBOL_GPL(isa_bridge_pcidev);
38
39 #define ISA_SPACE_MASK 0x1
40 #define ISA_SPACE_IO 0x1
41
remap_isa_base(phys_addr_t pa,unsigned long size)42 static void remap_isa_base(phys_addr_t pa, unsigned long size)
43 {
44 WARN_ON_ONCE(ISA_IO_BASE & ~PAGE_MASK);
45 WARN_ON_ONCE(pa & ~PAGE_MASK);
46 WARN_ON_ONCE(size & ~PAGE_MASK);
47
48 if (slab_is_available()) {
49 if (ioremap_page_range(ISA_IO_BASE, ISA_IO_BASE + size, pa,
50 pgprot_noncached(PAGE_KERNEL)))
51 vunmap_range(ISA_IO_BASE, ISA_IO_BASE + size);
52 } else {
53 early_ioremap_range(ISA_IO_BASE, pa, size,
54 pgprot_noncached(PAGE_KERNEL));
55 }
56 }
57
pci_process_ISA_OF_ranges(struct device_node * isa_node,unsigned long phb_io_base_phys)58 static void pci_process_ISA_OF_ranges(struct device_node *isa_node,
59 unsigned long phb_io_base_phys)
60 {
61 /* We should get some saner parsing here and remove these structs */
62 struct pci_address {
63 u32 a_hi;
64 u32 a_mid;
65 u32 a_lo;
66 };
67
68 struct isa_address {
69 u32 a_hi;
70 u32 a_lo;
71 };
72
73 struct isa_range {
74 struct isa_address isa_addr;
75 struct pci_address pci_addr;
76 unsigned int size;
77 };
78
79 const struct isa_range *range;
80 unsigned long pci_addr;
81 unsigned int isa_addr;
82 unsigned int size;
83 int rlen = 0;
84
85 range = of_get_property(isa_node, "ranges", &rlen);
86 if (range == NULL || (rlen < sizeof(struct isa_range)))
87 goto inval_range;
88
89 /* From "ISA Binding to 1275"
90 * The ranges property is laid out as an array of elements,
91 * each of which comprises:
92 * cells 0 - 1: an ISA address
93 * cells 2 - 4: a PCI address
94 * (size depending on dev->n_addr_cells)
95 * cell 5: the size of the range
96 */
97 if ((range->isa_addr.a_hi & ISA_SPACE_MASK) != ISA_SPACE_IO) {
98 range++;
99 rlen -= sizeof(struct isa_range);
100 if (rlen < sizeof(struct isa_range))
101 goto inval_range;
102 }
103 if ((range->isa_addr.a_hi & ISA_SPACE_MASK) != ISA_SPACE_IO)
104 goto inval_range;
105
106 isa_addr = range->isa_addr.a_lo;
107 pci_addr = (unsigned long) range->pci_addr.a_mid << 32 |
108 range->pci_addr.a_lo;
109
110 /* Assume these are both zero. Note: We could fix that and
111 * do a proper parsing instead ... oh well, that will do for
112 * now as nobody uses fancy mappings for ISA bridges
113 */
114 if ((pci_addr != 0) || (isa_addr != 0)) {
115 printk(KERN_ERR "unexpected isa to pci mapping: %s\n",
116 __func__);
117 return;
118 }
119
120 /* Align size and make sure it's cropped to 64K */
121 size = PAGE_ALIGN(range->size);
122 if (size > 0x10000)
123 size = 0x10000;
124
125 remap_isa_base(phb_io_base_phys, size);
126 return;
127
128 inval_range:
129 printk(KERN_ERR "no ISA IO ranges or unexpected isa range, "
130 "mapping 64k\n");
131 remap_isa_base(phb_io_base_phys, 0x10000);
132 }
133
134
135 /**
136 * isa_bridge_find_early - Find and map the ISA IO space early before
137 * main PCI discovery. This is optionally called by
138 * the arch code when adding PCI PHBs to get early
139 * access to ISA IO ports
140 */
isa_bridge_find_early(struct pci_controller * hose)141 void __init isa_bridge_find_early(struct pci_controller *hose)
142 {
143 struct device_node *np, *parent = NULL, *tmp;
144
145 /* If we already have an ISA bridge, bail off */
146 if (isa_bridge_devnode != NULL)
147 return;
148
149 /* For each "isa" node in the system. Note : we do a search by
150 * type and not by name. It might be better to do by name but that's
151 * what the code used to do and I don't want to break too much at
152 * once. We can look into changing that separately
153 */
154 for_each_node_by_type(np, "isa") {
155 /* Look for our hose being a parent */
156 for (parent = of_get_parent(np); parent;) {
157 if (parent == hose->dn) {
158 of_node_put(parent);
159 break;
160 }
161 tmp = parent;
162 parent = of_get_parent(parent);
163 of_node_put(tmp);
164 }
165 if (parent != NULL)
166 break;
167 }
168 if (np == NULL)
169 return;
170 isa_bridge_devnode = np;
171
172 /* Now parse the "ranges" property and setup the ISA mapping */
173 pci_process_ISA_OF_ranges(np, hose->io_base_phys);
174
175 /* Set the global ISA io base to indicate we have an ISA bridge */
176 isa_io_base = ISA_IO_BASE;
177
178 pr_debug("ISA bridge (early) is %pOF\n", np);
179 }
180
181 /**
182 * isa_bridge_find_early - Find and map the ISA IO space early before
183 * main PCI discovery. This is optionally called by
184 * the arch code when adding PCI PHBs to get early
185 * access to ISA IO ports
186 */
isa_bridge_init_non_pci(struct device_node * np)187 void __init isa_bridge_init_non_pci(struct device_node *np)
188 {
189 const __be32 *ranges, *pbasep = NULL;
190 int rlen, i, rs;
191 u32 na, ns, pna;
192 u64 cbase, pbase, size = 0;
193
194 /* If we already have an ISA bridge, bail off */
195 if (isa_bridge_devnode != NULL)
196 return;
197
198 pna = of_n_addr_cells(np);
199 if (of_property_read_u32(np, "#address-cells", &na) ||
200 of_property_read_u32(np, "#size-cells", &ns)) {
201 pr_warn("ISA: Non-PCI bridge %pOF is missing address format\n",
202 np);
203 return;
204 }
205
206 /* Check it's a supported address format */
207 if (na != 2 || ns != 1) {
208 pr_warn("ISA: Non-PCI bridge %pOF has unsupported address format\n",
209 np);
210 return;
211 }
212 rs = na + ns + pna;
213
214 /* Grab the ranges property */
215 ranges = of_get_property(np, "ranges", &rlen);
216 if (ranges == NULL || rlen < rs) {
217 pr_warn("ISA: Non-PCI bridge %pOF has absent or invalid ranges\n",
218 np);
219 return;
220 }
221
222 /* Parse it. We are only looking for IO space */
223 for (i = 0; (i + rs - 1) < rlen; i += rs) {
224 if (be32_to_cpup(ranges + i) != 1)
225 continue;
226 cbase = be32_to_cpup(ranges + i + 1);
227 size = of_read_number(ranges + i + na + pna, ns);
228 pbasep = ranges + i + na;
229 break;
230 }
231
232 /* Got something ? */
233 if (!size || !pbasep) {
234 pr_warn("ISA: Non-PCI bridge %pOF has no usable IO range\n",
235 np);
236 return;
237 }
238
239 /* Align size and make sure it's cropped to 64K */
240 size = PAGE_ALIGN(size);
241 if (size > 0x10000)
242 size = 0x10000;
243
244 /* Map pbase */
245 pbase = of_translate_address(np, pbasep);
246 if (pbase == OF_BAD_ADDR) {
247 pr_warn("ISA: Non-PCI bridge %pOF failed to translate IO base\n",
248 np);
249 return;
250 }
251
252 /* We need page alignment */
253 if ((cbase & ~PAGE_MASK) || (pbase & ~PAGE_MASK)) {
254 pr_warn("ISA: Non-PCI bridge %pOF has non aligned IO range\n",
255 np);
256 return;
257 }
258
259 /* Got it */
260 isa_bridge_devnode = np;
261
262 /* Set the global ISA io base to indicate we have an ISA bridge
263 * and map it
264 */
265 isa_io_base = ISA_IO_BASE;
266 remap_isa_base(pbase, size);
267
268 pr_debug("ISA: Non-PCI bridge is %pOF\n", np);
269 }
270
271 /**
272 * isa_bridge_find_late - Find and map the ISA IO space upon discovery of
273 * a new ISA bridge
274 */
isa_bridge_find_late(struct pci_dev * pdev,struct device_node * devnode)275 static void isa_bridge_find_late(struct pci_dev *pdev,
276 struct device_node *devnode)
277 {
278 struct pci_controller *hose = pci_bus_to_host(pdev->bus);
279
280 /* Store ISA device node and PCI device */
281 isa_bridge_devnode = of_node_get(devnode);
282 isa_bridge_pcidev = pdev;
283
284 /* Now parse the "ranges" property and setup the ISA mapping */
285 pci_process_ISA_OF_ranges(devnode, hose->io_base_phys);
286
287 /* Set the global ISA io base to indicate we have an ISA bridge */
288 isa_io_base = ISA_IO_BASE;
289
290 pr_debug("ISA bridge (late) is %pOF on %s\n",
291 devnode, pci_name(pdev));
292 }
293
294 /**
295 * isa_bridge_remove - Remove/unmap an ISA bridge
296 */
isa_bridge_remove(void)297 static void isa_bridge_remove(void)
298 {
299 pr_debug("ISA bridge removed !\n");
300
301 /* Clear the global ISA io base to indicate that we have no more
302 * ISA bridge. Note that drivers don't quite handle that, though
303 * we should probably do something about it. But do we ever really
304 * have ISA bridges being removed on machines using legacy devices ?
305 */
306 isa_io_base = ISA_IO_BASE;
307
308 /* Clear references to the bridge */
309 of_node_put(isa_bridge_devnode);
310 isa_bridge_devnode = NULL;
311 isa_bridge_pcidev = NULL;
312
313 /* Unmap the ISA area */
314 vunmap_range(ISA_IO_BASE, ISA_IO_BASE + 0x10000);
315 }
316
317 /**
318 * isa_bridge_notify - Get notified of PCI devices addition/removal
319 */
isa_bridge_notify(struct notifier_block * nb,unsigned long action,void * data)320 static int isa_bridge_notify(struct notifier_block *nb, unsigned long action,
321 void *data)
322 {
323 struct device *dev = data;
324 struct pci_dev *pdev = to_pci_dev(dev);
325 struct device_node *devnode = pci_device_to_OF_node(pdev);
326
327 switch(action) {
328 case BUS_NOTIFY_ADD_DEVICE:
329 /* Check if we have an early ISA device, without PCI dev */
330 if (isa_bridge_devnode && isa_bridge_devnode == devnode &&
331 !isa_bridge_pcidev) {
332 pr_debug("ISA bridge PCI attached: %s\n",
333 pci_name(pdev));
334 isa_bridge_pcidev = pdev;
335 }
336
337 /* Check if we have no ISA device, and this happens to be one,
338 * register it as such if it has an OF device
339 */
340 if (!isa_bridge_devnode && of_node_is_type(devnode, "isa"))
341 isa_bridge_find_late(pdev, devnode);
342
343 return 0;
344 case BUS_NOTIFY_DEL_DEVICE:
345 /* Check if this our existing ISA device */
346 if (pdev == isa_bridge_pcidev ||
347 (devnode && devnode == isa_bridge_devnode))
348 isa_bridge_remove();
349 return 0;
350 }
351 return 0;
352 }
353
354 static struct notifier_block isa_bridge_notifier = {
355 .notifier_call = isa_bridge_notify
356 };
357
358 /**
359 * isa_bridge_init - register to be notified of ISA bridge addition/removal
360 *
361 */
isa_bridge_init(void)362 static int __init isa_bridge_init(void)
363 {
364 bus_register_notifier(&pci_bus_type, &isa_bridge_notifier);
365 return 0;
366 }
367 arch_initcall(isa_bridge_init);
368