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
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 (vmap_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
58 static int process_ISA_OF_ranges(struct device_node *isa_node,
59 unsigned long phb_io_base_phys)
60 {
61 unsigned int size;
62 struct of_range_parser parser;
63 struct of_range range;
64
65 if (of_range_parser_init(&parser, isa_node))
66 goto inval_range;
67
68 for_each_of_range(&parser, &range) {
69 if ((range.flags & ISA_SPACE_MASK) != ISA_SPACE_IO)
70 continue;
71
72 if (range.cpu_addr == OF_BAD_ADDR) {
73 pr_err("ISA: Bad CPU mapping: %s\n", __func__);
74 return -EINVAL;
75 }
76
77 /* We need page alignment */
78 if ((range.bus_addr & ~PAGE_MASK) || (range.cpu_addr & ~PAGE_MASK)) {
79 pr_warn("ISA: bridge %pOF has non aligned IO range\n", isa_node);
80 return -EINVAL;
81 }
82
83 /* Align size and make sure it's cropped to 64K */
84 size = PAGE_ALIGN(range.size);
85 if (size > 0x10000)
86 size = 0x10000;
87
88 if (!phb_io_base_phys)
89 phb_io_base_phys = range.cpu_addr;
90
91 remap_isa_base(phb_io_base_phys, size);
92 return 0;
93 }
94
95 inval_range:
96 if (phb_io_base_phys) {
97 pr_err("no ISA IO ranges or unexpected isa range, mapping 64k\n");
98 remap_isa_base(phb_io_base_phys, 0x10000);
99 return 0;
100 }
101 return -EINVAL;
102 }
103
104
105 /**
106 * isa_bridge_find_early - Find and map the ISA IO space early before
107 * main PCI discovery. This is optionally called by
108 * the arch code when adding PCI PHBs to get early
109 * access to ISA IO ports
110 */
111 void __init isa_bridge_find_early(struct pci_controller *hose)
112 {
113 struct device_node *np, *parent = NULL, *tmp;
114
115 /* If we already have an ISA bridge, bail off */
116 if (isa_bridge_devnode != NULL)
117 return;
118
119 /* For each "isa" node in the system. Note : we do a search by
120 * type and not by name. It might be better to do by name but that's
121 * what the code used to do and I don't want to break too much at
122 * once. We can look into changing that separately
123 */
124 for_each_node_by_type(np, "isa") {
125 /* Look for our hose being a parent */
126 for (parent = of_get_parent(np); parent;) {
127 if (parent == hose->dn) {
128 of_node_put(parent);
129 break;
130 }
131 tmp = parent;
132 parent = of_get_parent(parent);
133 of_node_put(tmp);
134 }
135 if (parent != NULL)
136 break;
137 }
138 if (np == NULL)
139 return;
140 isa_bridge_devnode = np;
141
142 /* Now parse the "ranges" property and setup the ISA mapping */
143 process_ISA_OF_ranges(np, hose->io_base_phys);
144
145 /* Set the global ISA io base to indicate we have an ISA bridge */
146 isa_io_base = ISA_IO_BASE;
147
148 pr_debug("ISA bridge (early) is %pOF\n", np);
149 }
150
151 /**
152 * isa_bridge_find_early - Find and map the ISA IO space early before
153 * main PCI discovery. This is optionally called by
154 * the arch code when adding PCI PHBs to get early
155 * access to ISA IO ports
156 */
157 void __init isa_bridge_init_non_pci(struct device_node *np)
158 {
159 int ret;
160
161 /* If we already have an ISA bridge, bail off */
162 if (isa_bridge_devnode != NULL)
163 return;
164
165 ret = process_ISA_OF_ranges(np, 0);
166 if (ret)
167 return;
168
169 /* Got it */
170 isa_bridge_devnode = np;
171
172 /* Set the global ISA io base to indicate we have an ISA bridge
173 * and map it
174 */
175 isa_io_base = ISA_IO_BASE;
176
177 pr_debug("ISA: Non-PCI bridge is %pOF\n", np);
178 }
179
180 /**
181 * isa_bridge_find_late - Find and map the ISA IO space upon discovery of
182 * a new ISA bridge
183 */
184 static void isa_bridge_find_late(struct pci_dev *pdev,
185 struct device_node *devnode)
186 {
187 struct pci_controller *hose = pci_bus_to_host(pdev->bus);
188
189 /* Store ISA device node and PCI device */
190 isa_bridge_devnode = of_node_get(devnode);
191 isa_bridge_pcidev = pdev;
192
193 /* Now parse the "ranges" property and setup the ISA mapping */
194 process_ISA_OF_ranges(devnode, hose->io_base_phys);
195
196 /* Set the global ISA io base to indicate we have an ISA bridge */
197 isa_io_base = ISA_IO_BASE;
198
199 pr_debug("ISA bridge (late) is %pOF on %s\n",
200 devnode, pci_name(pdev));
201 }
202
203 /**
204 * isa_bridge_remove - Remove/unmap an ISA bridge
205 */
206 static void isa_bridge_remove(void)
207 {
208 pr_debug("ISA bridge removed !\n");
209
210 /* Clear the global ISA io base to indicate that we have no more
211 * ISA bridge. Note that drivers don't quite handle that, though
212 * we should probably do something about it. But do we ever really
213 * have ISA bridges being removed on machines using legacy devices ?
214 */
215 isa_io_base = ISA_IO_BASE;
216
217 /* Clear references to the bridge */
218 of_node_put(isa_bridge_devnode);
219 isa_bridge_devnode = NULL;
220 isa_bridge_pcidev = NULL;
221
222 /* Unmap the ISA area */
223 vunmap_range(ISA_IO_BASE, ISA_IO_BASE + 0x10000);
224 }
225
226 /**
227 * isa_bridge_notify - Get notified of PCI devices addition/removal
228 */
229 static int isa_bridge_notify(struct notifier_block *nb, unsigned long action,
230 void *data)
231 {
232 struct device *dev = data;
233 struct pci_dev *pdev = to_pci_dev(dev);
234 struct device_node *devnode = pci_device_to_OF_node(pdev);
235
236 switch(action) {
237 case BUS_NOTIFY_ADD_DEVICE:
238 /* Check if we have an early ISA device, without PCI dev */
239 if (isa_bridge_devnode && isa_bridge_devnode == devnode &&
240 !isa_bridge_pcidev) {
241 pr_debug("ISA bridge PCI attached: %s\n",
242 pci_name(pdev));
243 isa_bridge_pcidev = pdev;
244 }
245
246 /* Check if we have no ISA device, and this happens to be one,
247 * register it as such if it has an OF device
248 */
249 if (!isa_bridge_devnode && of_node_is_type(devnode, "isa"))
250 isa_bridge_find_late(pdev, devnode);
251
252 return 0;
253 case BUS_NOTIFY_DEL_DEVICE:
254 /* Check if this our existing ISA device */
255 if (pdev == isa_bridge_pcidev ||
256 (devnode && devnode == isa_bridge_devnode))
257 isa_bridge_remove();
258 return 0;
259 }
260 return 0;
261 }
262
263 static struct notifier_block isa_bridge_notifier = {
264 .notifier_call = isa_bridge_notify
265 };
266
267 /**
268 * isa_bridge_init - register to be notified of ISA bridge addition/removal
269 *
270 */
271 static int __init isa_bridge_init(void)
272 {
273 bus_register_notifier(&pci_bus_type, &isa_bridge_notifier);
274 return 0;
275 }
276 arch_initcall(isa_bridge_init);
277
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