[Bluetooth] Switch from OGF+OCF to using only opcodes
[linux-2.6/verdex.git] / drivers / lguest / lguest_bus.c
blob57329788f8a7235f35ba98fde5f31007bb275769
1 /*P:050 Lguest guests use a very simple bus for devices. It's a simple array
2 * of device descriptors contained just above the top of normal memory. The
3 * lguest bus is 80% tedious boilerplate code. :*/
4 #include <linux/init.h>
5 #include <linux/bootmem.h>
6 #include <linux/lguest_bus.h>
7 #include <asm/io.h>
8 #include <asm/paravirt.h>
10 static ssize_t type_show(struct device *_dev,
11 struct device_attribute *attr, char *buf)
13 struct lguest_device *dev = container_of(_dev,struct lguest_device,dev);
14 return sprintf(buf, "%hu", lguest_devices[dev->index].type);
16 static ssize_t features_show(struct device *_dev,
17 struct device_attribute *attr, char *buf)
19 struct lguest_device *dev = container_of(_dev,struct lguest_device,dev);
20 return sprintf(buf, "%hx", lguest_devices[dev->index].features);
22 static ssize_t pfn_show(struct device *_dev,
23 struct device_attribute *attr, char *buf)
25 struct lguest_device *dev = container_of(_dev,struct lguest_device,dev);
26 return sprintf(buf, "%u", lguest_devices[dev->index].pfn);
28 static ssize_t status_show(struct device *_dev,
29 struct device_attribute *attr, char *buf)
31 struct lguest_device *dev = container_of(_dev,struct lguest_device,dev);
32 return sprintf(buf, "%hx", lguest_devices[dev->index].status);
34 static ssize_t status_store(struct device *_dev, struct device_attribute *attr,
35 const char *buf, size_t count)
37 struct lguest_device *dev = container_of(_dev,struct lguest_device,dev);
38 if (sscanf(buf, "%hi", &lguest_devices[dev->index].status) != 1)
39 return -EINVAL;
40 return count;
42 static struct device_attribute lguest_dev_attrs[] = {
43 __ATTR_RO(type),
44 __ATTR_RO(features),
45 __ATTR_RO(pfn),
46 __ATTR(status, 0644, status_show, status_store),
47 __ATTR_NULL
50 /*D:130 The generic bus infrastructure requires a function which says whether a
51 * device matches a driver. For us, it is simple: "struct lguest_driver"
52 * contains a "device_type" field which indicates what type of device it can
53 * handle, so we just cast the args and compare: */
54 static int lguest_dev_match(struct device *_dev, struct device_driver *_drv)
56 struct lguest_device *dev = container_of(_dev,struct lguest_device,dev);
57 struct lguest_driver *drv = container_of(_drv,struct lguest_driver,drv);
59 return (drv->device_type == lguest_devices[dev->index].type);
61 /*:*/
63 struct lguest_bus {
64 struct bus_type bus;
65 struct device dev;
68 static struct lguest_bus lguest_bus = {
69 .bus = {
70 .name = "lguest",
71 .match = lguest_dev_match,
72 .dev_attrs = lguest_dev_attrs,
74 .dev = {
75 .parent = NULL,
76 .bus_id = "lguest",
80 /*D:140 This is the callback which occurs once the bus infrastructure matches
81 * up a device and driver, ie. in response to add_lguest_device() calling
82 * device_register(), or register_lguest_driver() calling driver_register().
84 * At the moment it's always the latter: the devices are added first, since
85 * scan_devices() is called from a "core_initcall", and the drivers themselves
86 * called later as a normal "initcall". But it would work the other way too.
88 * So now we have the happy couple, we add the status bit to indicate that we
89 * found a driver. If the driver truly loves the device, it will return
90 * happiness from its probe function (ok, perhaps this wasn't my greatest
91 * analogy), and we set the final "driver ok" bit so the Host sees it's all
92 * green. */
93 static int lguest_dev_probe(struct device *_dev)
95 int ret;
96 struct lguest_device*dev = container_of(_dev,struct lguest_device,dev);
97 struct lguest_driver*drv = container_of(dev->dev.driver,
98 struct lguest_driver, drv);
100 lguest_devices[dev->index].status |= LGUEST_DEVICE_S_DRIVER;
101 ret = drv->probe(dev);
102 if (ret == 0)
103 lguest_devices[dev->index].status |= LGUEST_DEVICE_S_DRIVER_OK;
104 return ret;
107 /* The last part of the bus infrastructure is the function lguest drivers use
108 * to register themselves. Firstly, we do nothing if there's no lguest bus
109 * (ie. this is not a Guest), otherwise we fill in the embedded generic "struct
110 * driver" fields and call the generic driver_register(). */
111 int register_lguest_driver(struct lguest_driver *drv)
113 if (!lguest_devices)
114 return 0;
116 drv->drv.bus = &lguest_bus.bus;
117 drv->drv.name = drv->name;
118 drv->drv.owner = drv->owner;
119 drv->drv.probe = lguest_dev_probe;
121 return driver_register(&drv->drv);
124 /* At the moment we build all the drivers into the kernel because they're so
125 * simple: 8144 bytes for all three of them as I type this. And as the console
126 * really needs to be built in, it's actually only 3527 bytes for the network
127 * and block drivers.
129 * If they get complex it will make sense for them to be modularized, so we
130 * need to explicitly export the symbol.
132 * I don't think non-GPL modules make sense, so it's a GPL-only export.
134 EXPORT_SYMBOL_GPL(register_lguest_driver);
136 /*D:120 This is the core of the lguest bus: actually adding a new device.
137 * It's a separate function because it's neater that way, and because an
138 * earlier version of the code supported hotplug and unplug. They were removed
139 * early on because they were never used.
141 * As Andrew Tridgell says, "Untested code is buggy code".
143 * It's worth reading this carefully: we start with an index into the array of
144 * "struct lguest_device_desc"s indicating the device which is new: */
145 static void add_lguest_device(unsigned int index)
147 struct lguest_device *new;
149 /* Each "struct lguest_device_desc" has a "status" field, which the
150 * Guest updates as the device is probed. In the worst case, the Host
151 * can look at these bits to tell what part of device setup failed,
152 * even if the console isn't available. */
153 lguest_devices[index].status |= LGUEST_DEVICE_S_ACKNOWLEDGE;
154 new = kmalloc(sizeof(struct lguest_device), GFP_KERNEL);
155 if (!new) {
156 printk(KERN_EMERG "Cannot allocate lguest device %u\n", index);
157 lguest_devices[index].status |= LGUEST_DEVICE_S_FAILED;
158 return;
161 /* The "struct lguest_device" setup is pretty straight-forward example
162 * code. */
163 new->index = index;
164 new->private = NULL;
165 memset(&new->dev, 0, sizeof(new->dev));
166 new->dev.parent = &lguest_bus.dev;
167 new->dev.bus = &lguest_bus.bus;
168 sprintf(new->dev.bus_id, "%u", index);
170 /* device_register() causes the bus infrastructure to look for a
171 * matching driver. */
172 if (device_register(&new->dev) != 0) {
173 printk(KERN_EMERG "Cannot register lguest device %u\n", index);
174 lguest_devices[index].status |= LGUEST_DEVICE_S_FAILED;
175 kfree(new);
179 /*D:110 scan_devices() simply iterates through the device array. The type 0
180 * is reserved to mean "no device", and anything else means we have found a
181 * device: add it. */
182 static void scan_devices(void)
184 unsigned int i;
186 for (i = 0; i < LGUEST_MAX_DEVICES; i++)
187 if (lguest_devices[i].type)
188 add_lguest_device(i);
191 /*D:100 Fairly early in boot, lguest_bus_init() is called to set up the lguest
192 * bus. We check that we are a Guest by checking paravirt_ops.name: there are
193 * other ways of checking, but this seems most obvious to me.
195 * So we can access the array of "struct lguest_device_desc"s easily, we map
196 * that memory and store the pointer in the global "lguest_devices". Then we
197 * register the bus with the core. Doing two registrations seems clunky to me,
198 * but it seems to be the correct sysfs incantation.
200 * Finally we call scan_devices() which adds all the devices found in the
201 * "struct lguest_device_desc" array. */
202 static int __init lguest_bus_init(void)
204 if (strcmp(pv_info.name, "lguest") != 0)
205 return 0;
207 /* Devices are in a single page above top of "normal" mem */
208 lguest_devices = lguest_map(max_pfn<<PAGE_SHIFT, 1);
210 if (bus_register(&lguest_bus.bus) != 0
211 || device_register(&lguest_bus.dev) != 0)
212 panic("lguest bus registration failed");
214 scan_devices();
215 return 0;
217 /* Do this after core stuff, before devices. */
218 postcore_initcall(lguest_bus_init);