Linux-2.6.12-rc2
[linux-3.10.git] / Documentation / firmware_class / firmware_sample_driver.c
1 /*
2  * firmware_sample_driver.c -
3  *
4  * Copyright (c) 2003 Manuel Estrada Sainz <ranty@debian.org>
5  *
6  * Sample code on how to use request_firmware() from drivers.
7  *
8  * Note that register_firmware() is currently useless.
9  *
10  */
11
12 #include <linux/module.h>
13 #include <linux/kernel.h>
14 #include <linux/init.h>
15 #include <linux/device.h>
16
17 #include "linux/firmware.h"
18
19 #define WE_CAN_NEED_FIRMWARE_BEFORE_USERSPACE_IS_AVAILABLE
20 #ifdef WE_CAN_NEED_FIRMWARE_BEFORE_USERSPACE_IS_AVAILABLE
21 char __init inkernel_firmware[] = "let's say that this is firmware\n";
22 #endif
23
24 static struct device ghost_device = {
25         .name      = "Ghost Device",
26         .bus_id    = "ghost0",
27 };
28
29
30 static void sample_firmware_load(char *firmware, int size)
31 {
32         u8 buf[size+1];
33         memcpy(buf, firmware, size);
34         buf[size] = '\0';
35         printk("firmware_sample_driver: firmware: %s\n", buf);
36 }
37
38 static void sample_probe_default(void)
39 {
40         /* uses the default method to get the firmware */
41         const struct firmware *fw_entry;
42         printk("firmware_sample_driver: a ghost device got inserted :)\n");
43
44         if(request_firmware(&fw_entry, "sample_driver_fw", &ghost_device)!=0)
45         {
46                 printk(KERN_ERR
47                        "firmware_sample_driver: Firmware not available\n");
48                 return;
49         }
50         
51         sample_firmware_load(fw_entry->data, fw_entry->size);
52
53         release_firmware(fw_entry);
54
55         /* finish setting up the device */
56 }
57 static void sample_probe_specific(void)
58 {
59         /* Uses some specific hotplug support to get the firmware from
60          * userspace  directly into the hardware, or via some sysfs file */
61
62         /* NOTE: This currently doesn't work */
63
64         printk("firmware_sample_driver: a ghost device got inserted :)\n");
65
66         if(request_firmware(NULL, "sample_driver_fw", &ghost_device)!=0)
67         {
68                 printk(KERN_ERR
69                        "firmware_sample_driver: Firmware load failed\n");
70                 return;
71         }
72         
73         /* request_firmware blocks until userspace finished, so at
74          * this point the firmware should be already in the device */
75
76         /* finish setting up the device */
77 }
78 static void sample_probe_async_cont(const struct firmware *fw, void *context)
79 {
80         if(!fw){
81                 printk(KERN_ERR
82                        "firmware_sample_driver: firmware load failed\n");
83                 return;
84         }
85
86         printk("firmware_sample_driver: device pointer \"%s\"\n",
87                (char *)context);
88         sample_firmware_load(fw->data, fw->size);
89 }
90 static void sample_probe_async(void)
91 {
92         /* Let's say that I can't sleep */
93         int error;
94         error = request_firmware_nowait (THIS_MODULE,
95                                          "sample_driver_fw", &ghost_device,
96                                          "my device pointer",
97                                          sample_probe_async_cont);
98         if(error){
99                 printk(KERN_ERR 
100                        "firmware_sample_driver:"
101                        " request_firmware_nowait failed\n");
102         }
103 }
104
105 static int sample_init(void)
106 {
107 #ifdef WE_CAN_NEED_FIRMWARE_BEFORE_USERSPACE_IS_AVAILABLE
108         register_firmware("sample_driver_fw", inkernel_firmware,
109                           sizeof(inkernel_firmware));
110 #endif
111         device_initialize(&ghost_device);
112         /* since there is no real hardware insertion I just call the
113          * sample probe functions here */
114         sample_probe_specific();
115         sample_probe_default();
116         sample_probe_async();
117         return 0;
118 }
119 static void __exit sample_exit(void)
120 {
121 }
122
123 module_init (sample_init);
124 module_exit (sample_exit);
125
126 MODULE_LICENSE("GPL");