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