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