/arch/powerpc/kernel/isa-bridge.c

  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
 30unsigned long isa_io_base;	/* NULL if no ISA bus */
 31EXPORT_SYMBOL(isa_io_base);
 32
 33/* Cached ISA bridge dev. */
 34static struct device_node *isa_bridge_devnode;
 35struct pci_dev *isa_bridge_pcidev;
 36EXPORT_SYMBOL_GPL(isa_bridge_pcidev);
 37
 38#define ISA_SPACE_MASK 0x1
 39#define ISA_SPACE_IO 0x1
 40
 41static 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
112inval_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 */
126void __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 */
172void __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 */
261static 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 */
283static 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 */
306static 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
340static 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 */
348static int __init isa_bridge_init(void)
349{
350	bus_register_notifier(&pci_bus_type, &isa_bridge_notifier);
351	return 0;
352}
353arch_initcall(isa_bridge_init);