1/*
2 * Routines for tracking a legacy ISA bridge
3 *
4 * Copyrigh 2007 Benjamin Herrenschmidt <benh@kernel.crashing.org>, IBM Corp.
5 *
6 * Some bits and pieces moved over from pci_64.c
7 *
8 * Copyrigh 2003 Anton Blanchard <anton@au.ibm.com>, IBM Corp.
9 *
10 *      This program is free software; you can redistribute it and/or
11 *      modify it under the terms of the GNU General Public License
12 *      as published by the Free Software Foundation; either version
13 *      2 of the License, or (at your option) any later version.
14 */
15
16#define DEBUG
17
18#include <linux/kernel.h>
19#include <linux/pci.h>
20#include <linux/string.h>
21#include <linux/export.h>
22#include <linux/init.h>
23#include <linux/mm.h>
24#include <linux/notifier.h>
25
26#include <asm/processor.h>
27#include <asm/io.h>
28#include <asm/prom.h>
29#include <asm/pci-bridge.h>
30#include <asm/machdep.h>
31#include <asm/ppc-pci.h>
32
33unsigned long isa_io_base;	/* NULL if no ISA bus */
34EXPORT_SYMBOL(isa_io_base);
35
36/* Cached ISA bridge dev. */
37static struct device_node *isa_bridge_devnode;
38struct pci_dev *isa_bridge_pcidev;
39EXPORT_SYMBOL_GPL(isa_bridge_pcidev);
40
41#define ISA_SPACE_MASK 0x1
42#define ISA_SPACE_IO 0x1
43
44static void pci_process_ISA_OF_ranges(struct device_node *isa_node,
45				      unsigned long phb_io_base_phys)
46{
47	/* We should get some saner parsing here and remove these structs */
48	struct pci_address {
49		u32 a_hi;
50		u32 a_mid;
51		u32 a_lo;
52	};
53
54	struct isa_address {
55		u32 a_hi;
56		u32 a_lo;
57	};
58
59	struct isa_range {
60		struct isa_address isa_addr;
61		struct pci_address pci_addr;
62		unsigned int size;
63	};
64
65	const struct isa_range *range;
66	unsigned long pci_addr;
67	unsigned int isa_addr;
68	unsigned int size;
69	int rlen = 0;
70
71	range = of_get_property(isa_node, "ranges", &rlen);
72	if (range == NULL || (rlen < sizeof(struct isa_range)))
73		goto inval_range;
74
75	/* From "ISA Binding to 1275"
76	 * The ranges property is laid out as an array of elements,
77	 * each of which comprises:
78	 *   cells 0 - 1:	an ISA address
79	 *   cells 2 - 4:	a PCI address
80	 *			(size depending on dev->n_addr_cells)
81	 *   cell 5:		the size of the range
82	 */
83	if ((range->isa_addr.a_hi & ISA_SPACE_MASK) != ISA_SPACE_IO) {
84		range++;
85		rlen -= sizeof(struct isa_range);
86		if (rlen < sizeof(struct isa_range))
87			goto inval_range;
88	}
89	if ((range->isa_addr.a_hi & ISA_SPACE_MASK) != ISA_SPACE_IO)
90		goto inval_range;
91
92	isa_addr = range->isa_addr.a_lo;
93	pci_addr = (unsigned long) range->pci_addr.a_mid << 32 |
94		range->pci_addr.a_lo;
95
96	/* Assume these are both zero. Note: We could fix that and
97	 * do a proper parsing instead ... oh well, that will do for
98	 * now as nobody uses fancy mappings for ISA bridges
99	 */
100	if ((pci_addr != 0) || (isa_addr != 0)) {
101		printk(KERN_ERR "unexpected isa to pci mapping: %s\n",
102		       __func__);
103		return;
104	}
105
106	/* Align size and make sure it's cropped to 64K */
107	size = PAGE_ALIGN(range->size);
108	if (size > 0x10000)
109		size = 0x10000;
110
111	__ioremap_at(phb_io_base_phys, (void *)ISA_IO_BASE,
112		     size, _PAGE_NO_CACHE|_PAGE_GUARDED);
113	return;
114
115inval_range:
116	printk(KERN_ERR "no ISA IO ranges or unexpected isa range, "
117	       "mapping 64k\n");
118	__ioremap_at(phb_io_base_phys, (void *)ISA_IO_BASE,
119		     0x10000, _PAGE_NO_CACHE|_PAGE_GUARDED);
120}
121
122
123/**
124 * isa_bridge_find_early - Find and map the ISA IO space early before
125 *                         main PCI discovery. This is optionally called by
126 *                         the arch code when adding PCI PHBs to get early
127 *                         access to ISA IO ports
128 */
129void __init isa_bridge_find_early(struct pci_controller *hose)
130{
131	struct device_node *np, *parent = NULL, *tmp;
132
133	/* If we already have an ISA bridge, bail off */
134	if (isa_bridge_devnode != NULL)
135		return;
136
137	/* For each "isa" node in the system. Note : we do a search by
138	 * type and not by name. It might be better to do by name but that's
139	 * what the code used to do and I don't want to break too much at
140	 * once. We can look into changing that separately
141	 */
142	for_each_node_by_type(np, "isa") {
143		/* Look for our hose being a parent */
144		for (parent = of_get_parent(np); parent;) {
145			if (parent == hose->dn) {
146				of_node_put(parent);
147				break;
148			}
149			tmp = parent;
150			parent = of_get_parent(parent);
151			of_node_put(tmp);
152		}
153		if (parent != NULL)
154			break;
155	}
156	if (np == NULL)
157		return;
158	isa_bridge_devnode = np;
159
160	/* Now parse the "ranges" property and setup the ISA mapping */
161	pci_process_ISA_OF_ranges(np, hose->io_base_phys);
162
163	/* Set the global ISA io base to indicate we have an ISA bridge */
164	isa_io_base = ISA_IO_BASE;
165
166	pr_debug("ISA bridge (early) is %s\n", np->full_name);
167}
168
169/**
170 * isa_bridge_find_late - Find and map the ISA IO space upon discovery of
171 *                        a new ISA bridge
172 */
173static void isa_bridge_find_late(struct pci_dev *pdev,
174				 struct device_node *devnode)
175{
176	struct pci_controller *hose = pci_bus_to_host(pdev->bus);
177
178	/* Store ISA device node and PCI device */
179	isa_bridge_devnode = of_node_get(devnode);
180	isa_bridge_pcidev = pdev;
181
182	/* Now parse the "ranges" property and setup the ISA mapping */
183	pci_process_ISA_OF_ranges(devnode, hose->io_base_phys);
184
185	/* Set the global ISA io base to indicate we have an ISA bridge */
186	isa_io_base = ISA_IO_BASE;
187
188	pr_debug("ISA bridge (late) is %s on %s\n",
189		 devnode->full_name, pci_name(pdev));
190}
191
192/**
193 * isa_bridge_remove - Remove/unmap an ISA bridge
194 */
195static void isa_bridge_remove(void)
196{
197	pr_debug("ISA bridge removed !\n");
198
199	/* Clear the global ISA io base to indicate that we have no more
200	 * ISA bridge. Note that drivers don't quite handle that, though
201	 * we should probably do something about it. But do we ever really
202	 * have ISA bridges being removed on machines using legacy devices ?
203	 */
204	isa_io_base = ISA_IO_BASE;
205
206	/* Clear references to the bridge */
207	of_node_put(isa_bridge_devnode);
208	isa_bridge_devnode = NULL;
209	isa_bridge_pcidev = NULL;
210
211	/* Unmap the ISA area */
212	__iounmap_at((void *)ISA_IO_BASE, 0x10000);
213}
214
215/**
216 * isa_bridge_notify - Get notified of PCI devices addition/removal
217 */
218static int isa_bridge_notify(struct notifier_block *nb, unsigned long action,
219			     void *data)
220{
221	struct device *dev = data;
222	struct pci_dev *pdev = to_pci_dev(dev);
223	struct device_node *devnode = pci_device_to_OF_node(pdev);
224
225	switch(action) {
226	case BUS_NOTIFY_ADD_DEVICE:
227		/* Check if we have an early ISA device, without PCI dev */
228		if (isa_bridge_devnode && isa_bridge_devnode == devnode &&
229		    !isa_bridge_pcidev) {
230			pr_debug("ISA bridge PCI attached: %s\n",
231				 pci_name(pdev));
232			isa_bridge_pcidev = pdev;
233		}
234
235		/* Check if we have no ISA device, and this happens to be one,
236		 * register it as such if it has an OF device
237		 */
238		if (!isa_bridge_devnode && devnode && devnode->type &&
239		    !strcmp(devnode->type, "isa"))
240			isa_bridge_find_late(pdev, devnode);
241
242		return 0;
243	case BUS_NOTIFY_DEL_DEVICE:
244		/* Check if this our existing ISA device */
245		if (pdev == isa_bridge_pcidev ||
246		    (devnode && devnode == isa_bridge_devnode))
247			isa_bridge_remove();
248		return 0;
249	}
250	return 0;
251}
252
253static struct notifier_block isa_bridge_notifier = {
254	.notifier_call = isa_bridge_notify
255};
256
257/**
258 * isa_bridge_init - register to be notified of ISA bridge addition/removal
259 *
260 */
261static int __init isa_bridge_init(void)
262{
263	bus_register_notifier(&pci_bus_type, &isa_bridge_notifier);
264	return 0;
265}
266arch_initcall(isa_bridge_init);
267