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