xref: /openbmc/linux/drivers/pci/bus.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
1 /*
2  *	drivers/pci/bus.c
3  *
4  * From setup-res.c, by:
5  *	Dave Rusling (david.rusling@reo.mts.dec.com)
6  *	David Mosberger (davidm@cs.arizona.edu)
7  *	David Miller (davem@redhat.com)
8  *	Ivan Kokshaysky (ink@jurassic.park.msu.ru)
9  */
10 #include <linux/module.h>
11 #include <linux/kernel.h>
12 #include <linux/pci.h>
13 #include <linux/errno.h>
14 #include <linux/ioport.h>
15 #include <linux/proc_fs.h>
16 #include <linux/init.h>
17 
18 #include "pci.h"
19 
20 /**
21  * pci_bus_alloc_resource - allocate a resource from a parent bus
22  * @bus: PCI bus
23  * @res: resource to allocate
24  * @size: size of resource to allocate
25  * @align: alignment of resource to allocate
26  * @min: minimum /proc/iomem address to allocate
27  * @type_mask: IORESOURCE_* type flags
28  * @alignf: resource alignment function
29  * @alignf_data: data argument for resource alignment function
30  *
31  * Given the PCI bus a device resides on, the size, minimum address,
32  * alignment and type, try to find an acceptable resource allocation
33  * for a specific device resource.
34  */
35 int
36 pci_bus_alloc_resource(struct pci_bus *bus, struct resource *res,
37 		resource_size_t size, resource_size_t align,
38 		resource_size_t min, unsigned int type_mask,
39 		void (*alignf)(void *, struct resource *, resource_size_t,
40 				resource_size_t),
41 		void *alignf_data)
42 {
43 	int i, ret = -ENOMEM;
44 
45 	type_mask |= IORESOURCE_IO | IORESOURCE_MEM;
46 
47 	for (i = 0; i < PCI_BUS_NUM_RESOURCES; i++) {
48 		struct resource *r = bus->resource[i];
49 		if (!r)
50 			continue;
51 
52 		/* type_mask must match */
53 		if ((res->flags ^ r->flags) & type_mask)
54 			continue;
55 
56 		/* We cannot allocate a non-prefetching resource
57 		   from a pre-fetching area */
58 		if ((r->flags & IORESOURCE_PREFETCH) &&
59 		    !(res->flags & IORESOURCE_PREFETCH))
60 			continue;
61 
62 		/* Ok, try it out.. */
63 		ret = allocate_resource(r, res, size,
64 					r->start ? : min,
65 					-1, align,
66 					alignf, alignf_data);
67 		if (ret == 0)
68 			break;
69 	}
70 	return ret;
71 }
72 
73 /**
74  * add a single device
75  * @dev: device to add
76  *
77  * This adds a single pci device to the global
78  * device list and adds sysfs and procfs entries
79  */
80 int pci_bus_add_device(struct pci_dev *dev)
81 {
82 	int retval;
83 	retval = device_add(&dev->dev);
84 	if (retval)
85 		return retval;
86 
87 	down_write(&pci_bus_sem);
88 	list_add_tail(&dev->global_list, &pci_devices);
89 	up_write(&pci_bus_sem);
90 
91 	pci_proc_attach_device(dev);
92 	pci_create_sysfs_dev_files(dev);
93 	return 0;
94 }
95 
96 /**
97  * pci_bus_add_devices - insert newly discovered PCI devices
98  * @bus: bus to check for new devices
99  *
100  * Add newly discovered PCI devices (which are on the bus->devices
101  * list) to the global PCI device list, add the sysfs and procfs
102  * entries.  Where a bridge is found, add the discovered bus to
103  * the parents list of child buses, and recurse (breadth-first
104  * to be compatible with 2.4)
105  *
106  * Call hotplug for each new devices.
107  */
108 void pci_bus_add_devices(struct pci_bus *bus)
109 {
110 	struct pci_dev *dev;
111 	int retval;
112 
113 	list_for_each_entry(dev, &bus->devices, bus_list) {
114 		/*
115 		 * Skip already-present devices (which are on the
116 		 * global device list.)
117 		 */
118 		if (!list_empty(&dev->global_list))
119 			continue;
120 		retval = pci_bus_add_device(dev);
121 		if (retval)
122 			dev_err(&dev->dev, "Error adding device, continuing\n");
123 	}
124 
125 	list_for_each_entry(dev, &bus->devices, bus_list) {
126 
127 		BUG_ON(list_empty(&dev->global_list));
128 
129 		/*
130 		 * If there is an unattached subordinate bus, attach
131 		 * it and then scan for unattached PCI devices.
132 		 */
133 		if (dev->subordinate) {
134 		       if (list_empty(&dev->subordinate->node)) {
135 			       down_write(&pci_bus_sem);
136 			       list_add_tail(&dev->subordinate->node,
137 					       &dev->bus->children);
138 			       up_write(&pci_bus_sem);
139 			}
140 			pci_bus_add_devices(dev->subordinate);
141 			retval = sysfs_create_link(&dev->subordinate->class_dev.kobj,
142 						   &dev->dev.kobj, "bridge");
143 			if (retval)
144 				dev_err(&dev->dev, "Error creating sysfs "
145 					"bridge symlink, continuing...\n");
146 		}
147 	}
148 }
149 
150 void pci_enable_bridges(struct pci_bus *bus)
151 {
152 	struct pci_dev *dev;
153 	int retval;
154 
155 	list_for_each_entry(dev, &bus->devices, bus_list) {
156 		if (dev->subordinate) {
157 			retval = pci_enable_device(dev);
158 			pci_set_master(dev);
159 			pci_enable_bridges(dev->subordinate);
160 		}
161 	}
162 }
163 
164 /** pci_walk_bus - walk devices on/under bus, calling callback.
165  *  @top      bus whose devices should be walked
166  *  @cb       callback to be called for each device found
167  *  @userdata arbitrary pointer to be passed to callback.
168  *
169  *  Walk the given bus, including any bridged devices
170  *  on buses under this bus.  Call the provided callback
171  *  on each device found.
172  */
173 void pci_walk_bus(struct pci_bus *top, void (*cb)(struct pci_dev *, void *),
174 		  void *userdata)
175 {
176 	struct pci_dev *dev;
177 	struct pci_bus *bus;
178 	struct list_head *next;
179 
180 	bus = top;
181 	down_read(&pci_bus_sem);
182 	next = top->devices.next;
183 	for (;;) {
184 		if (next == &bus->devices) {
185 			/* end of this bus, go up or finish */
186 			if (bus == top)
187 				break;
188 			next = bus->self->bus_list.next;
189 			bus = bus->self->bus;
190 			continue;
191 		}
192 		dev = list_entry(next, struct pci_dev, bus_list);
193 		if (dev->subordinate) {
194 			/* this is a pci-pci bridge, do its devices next */
195 			next = dev->subordinate->devices.next;
196 			bus = dev->subordinate;
197 		} else
198 			next = dev->bus_list.next;
199 
200 		/* Run device routines with the device locked */
201 		down(&dev->dev.sem);
202 		cb(dev, userdata);
203 		up(&dev->dev.sem);
204 	}
205 	up_read(&pci_bus_sem);
206 }
207 EXPORT_SYMBOL_GPL(pci_walk_bus);
208 
209 EXPORT_SYMBOL(pci_bus_alloc_resource);
210 EXPORT_SYMBOL_GPL(pci_bus_add_device);
211 EXPORT_SYMBOL(pci_bus_add_devices);
212 EXPORT_SYMBOL(pci_enable_bridges);
213