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         .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(KERN_INFO "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(KERN_INFO "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(KERN_INFO "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(KERN_INFO "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, FW_ACTION_NOHOTPLUG,
  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");