1 | /* |
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2 | * diskdevs.c - Physical and logical block devices (disks) support |
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3 | * |
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4 | * Copyright (C) 2001 OKTET Ltd., St.-Petersburg, Russia |
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5 | * Author: Victor V. Vengerov <vvv@oktet.ru> |
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6 | * |
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7 | * @(#) $Id$ |
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8 | */ |
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9 | |
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10 | #if HAVE_CONFIG_H |
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11 | #include "config.h" |
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12 | #endif |
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13 | |
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14 | #include <rtems.h> |
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15 | #include <rtems/libio.h> |
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16 | #include <stdlib.h> |
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17 | #include <unistd.h> /* unlink */ |
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18 | #include <string.h> |
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19 | |
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20 | #include "rtems/diskdevs.h" |
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21 | #include "rtems/bdbuf.h" |
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22 | |
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23 | #define DISKTAB_INITIAL_SIZE 32 |
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24 | |
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25 | /* Table of disk devices having the same major number */ |
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26 | typedef struct rtems_disk_device_table { |
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27 | rtems_disk_device **minor; /* minor-indexed disk device table */ |
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28 | uint32_t size; /* Number of entries in the table */ |
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29 | } rtems_disk_device_table; |
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30 | |
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31 | /* Pointer to [major].minor[minor] indexed array of disk devices */ |
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32 | static rtems_disk_device_table *disktab; |
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33 | |
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34 | /* Number of allocated entries in disktab table */ |
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35 | static uint32_t disktab_size; |
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36 | |
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37 | /* Mutual exclusion semaphore for disk devices table */ |
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38 | static rtems_id diskdevs_mutex; |
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39 | |
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40 | /* Flag meaning that disk I/O, buffering etc. already has been initialized. */ |
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41 | static boolean disk_io_initialized = FALSE; |
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42 | |
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43 | /* diskdevs data structures protection flag. |
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44 | * Normally, only table lookup operations performed. It is quite fast, so |
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45 | * it is possible to done lookups when interrupts are disabled, avoiding |
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46 | * obtaining the semaphore. This flags sets immediately after entering in |
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47 | * mutex-protected section and cleared before leaving this section in |
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48 | * "big" primitives like add/delete new device etc. Lookup function first |
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49 | * disable interrupts and check this flag. If it is set, lookup function |
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50 | * will be blocked on semaphore and lookup operation will be performed in |
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51 | * semaphore-protected code. If it is not set (very-very frequent case), |
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52 | * we can do lookup safely, enable interrupts and return result. |
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53 | */ |
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54 | static volatile bool diskdevs_protected; |
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55 | |
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56 | /* create_disk_entry -- |
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57 | * Return pointer to the disk_entry structure for the specified device, or |
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58 | * create one if it is not exists. |
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59 | * |
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60 | * PARAMETERS: |
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61 | * dev - device id (major, minor) |
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62 | * |
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63 | * RETURNS: |
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64 | * pointer to the disk device descriptor entry, or NULL if no memory |
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65 | * available for its creation. |
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66 | */ |
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67 | static rtems_disk_device * |
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68 | create_disk_entry(dev_t dev) |
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69 | { |
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70 | rtems_device_major_number major; |
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71 | rtems_device_minor_number minor; |
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72 | rtems_disk_device **d; |
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73 | |
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74 | rtems_filesystem_split_dev_t (dev, major, minor); |
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75 | |
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76 | if (major >= disktab_size) |
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77 | { |
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78 | rtems_disk_device_table *p; |
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79 | uint32_t newsize; |
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80 | uint32_t i; |
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81 | newsize = disktab_size * 2; |
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82 | if (major >= newsize) |
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83 | newsize = major + 1; |
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84 | p = realloc(disktab, sizeof(rtems_disk_device_table) * newsize); |
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85 | if (p == NULL) |
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86 | return NULL; |
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87 | disktab = p; |
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88 | p += disktab_size; |
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89 | for (i = disktab_size; i < newsize; i++, p++) |
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90 | { |
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91 | p->minor = NULL; |
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92 | p->size = 0; |
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93 | } |
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94 | disktab_size = newsize; |
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95 | } |
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96 | |
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97 | if ((disktab[major].minor == NULL) || |
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98 | (minor >= disktab[major].size)) |
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99 | { |
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100 | uint32_t newsize; |
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101 | rtems_disk_device **p; |
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102 | uint32_t i; |
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103 | uint32_t s = disktab[major].size; |
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104 | |
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105 | if (s == 0) |
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106 | newsize = DISKTAB_INITIAL_SIZE; |
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107 | else |
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108 | newsize = s * 2; |
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109 | if (minor >= newsize) |
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110 | newsize = minor + 1; |
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111 | |
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112 | p = realloc(disktab[major].minor, |
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113 | sizeof(rtems_disk_device *) * newsize); |
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114 | if (p == NULL) |
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115 | return NULL; |
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116 | disktab[major].minor = p; |
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117 | p += s; |
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118 | for (i = s; i < newsize; i++, p++) |
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119 | *p = NULL; |
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120 | disktab[major].size = newsize; |
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121 | } |
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122 | |
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123 | d = disktab[major].minor + minor; |
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124 | if (*d == NULL) |
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125 | { |
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126 | *d = calloc(1, sizeof(rtems_disk_device)); |
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127 | } |
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128 | return *d; |
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129 | } |
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130 | |
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131 | /* get_disk_entry -- |
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132 | * Get disk device descriptor by device number. |
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133 | * |
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134 | * PARAMETERS: |
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135 | * dev - block device number |
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136 | * |
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137 | * RETURNS: |
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138 | * Pointer to the disk device descriptor corresponding to the specified |
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139 | * device number, or NULL if disk device with such number not exists. |
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140 | */ |
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141 | static rtems_disk_device * |
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142 | get_disk_entry(dev_t dev) |
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143 | { |
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144 | rtems_device_major_number major; |
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145 | rtems_device_minor_number minor; |
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146 | rtems_disk_device_table *dtab; |
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147 | |
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148 | rtems_filesystem_split_dev_t (dev, major, minor); |
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149 | |
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150 | if ((major >= disktab_size) || (disktab == NULL)) |
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151 | return NULL; |
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152 | |
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153 | dtab = disktab + major; |
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154 | |
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155 | if ((minor >= dtab->size) || (dtab->minor == NULL)) |
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156 | return NULL; |
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157 | |
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158 | return dtab->minor[minor]; |
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159 | } |
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160 | |
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161 | /* create_disk -- |
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162 | * Check that disk entry for specified device number is not defined |
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163 | * and create it. |
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164 | * |
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165 | * PARAMETERS: |
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166 | * dev - device identifier (major, minor numbers) |
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167 | * name - character name of device (e.g. /dev/hda) |
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168 | * disdev - placeholder for pointer to created disk descriptor |
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169 | * |
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170 | * RETURNS: |
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171 | * RTEMS_SUCCESSFUL if disk entry successfully created, or |
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172 | * error code if error occured (device already registered, |
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173 | * no memory available). |
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174 | */ |
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175 | static rtems_status_code |
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176 | create_disk(dev_t dev, const char *name, rtems_disk_device **diskdev) |
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177 | { |
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178 | rtems_disk_device *dd; |
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179 | char *n; |
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180 | |
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181 | dd = get_disk_entry(dev); |
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182 | if (dd != NULL) |
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183 | { |
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184 | return RTEMS_RESOURCE_IN_USE; |
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185 | } |
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186 | |
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187 | if (name == NULL) |
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188 | { |
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189 | n = NULL; |
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190 | } |
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191 | else |
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192 | { |
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193 | int nlen = strlen(name) + 1; |
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194 | n = malloc(nlen); |
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195 | if (n == NULL) |
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196 | return RTEMS_NO_MEMORY; |
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197 | strncpy(n, name, nlen); |
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198 | } |
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199 | |
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200 | dd = create_disk_entry(dev); |
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201 | if (dd == NULL) |
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202 | { |
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203 | free(n); |
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204 | return RTEMS_NO_MEMORY; |
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205 | } |
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206 | |
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207 | dd->dev = dev; |
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208 | dd->name = n; |
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209 | |
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210 | *diskdev = dd; |
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211 | |
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212 | return RTEMS_SUCCESSFUL; |
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213 | } |
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214 | |
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215 | /* rtems_disk_create_phys -- |
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216 | * Create physical disk entry. This function usually invoked from |
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217 | * block device driver initialization code when physical device |
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218 | * detected in the system. Device driver should provide ioctl handler |
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219 | * to allow block device access operations. This primitive will register |
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220 | * device in rtems (invoke rtems_io_register_name). |
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221 | * |
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222 | * PARAMETERS: |
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223 | * dev - device identifier (major, minor numbers) |
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224 | * block_size - size of disk block (minimum data transfer unit); must be |
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225 | * power of 2 |
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226 | * disk_size - number of blocks on device |
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227 | * handler - IOCTL handler (function providing basic block input/output |
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228 | * request handling BIOREQUEST and other device management |
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229 | * operations) |
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230 | * name - character name of device (e.g. /dev/hda) |
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231 | * |
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232 | * RETURNS: |
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233 | * RTEMS_SUCCESSFUL if information about new physical disk added, or |
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234 | * error code if error occured (device already registered, wrong block |
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235 | * size value, no memory available). |
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236 | */ |
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237 | rtems_status_code |
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238 | rtems_disk_create_phys(dev_t dev, int block_size, int disk_size, |
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239 | rtems_block_device_ioctl handler, |
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240 | const char *name) |
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241 | { |
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242 | int bs_log2; |
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243 | int i; |
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244 | rtems_disk_device *dd; |
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245 | rtems_status_code rc; |
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246 | rtems_bdpool_id pool; |
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247 | rtems_device_major_number major; |
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248 | rtems_device_minor_number minor; |
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249 | |
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250 | rtems_filesystem_split_dev_t (dev, major, minor); |
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251 | |
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252 | |
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253 | for (bs_log2 = 0, i = block_size; (i & 1) == 0; i >>= 1, bs_log2++); |
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254 | if ((bs_log2 < 9) || (i != 1)) /* block size < 512 or not power of 2 */ |
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255 | return RTEMS_INVALID_NUMBER; |
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256 | |
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257 | rc = rtems_semaphore_obtain(diskdevs_mutex, RTEMS_WAIT, RTEMS_NO_TIMEOUT); |
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258 | if (rc != RTEMS_SUCCESSFUL) |
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259 | return rc; |
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260 | diskdevs_protected = TRUE; |
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261 | |
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262 | rc = rtems_bdbuf_find_pool(block_size, &pool); |
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263 | if (rc != RTEMS_SUCCESSFUL) |
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264 | { |
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265 | diskdevs_protected = FALSE; |
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266 | rtems_semaphore_release(diskdevs_mutex); |
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267 | return rc; |
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268 | } |
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269 | |
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270 | rc = create_disk(dev, name, &dd); |
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271 | if (rc != RTEMS_SUCCESSFUL) |
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272 | { |
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273 | diskdevs_protected = FALSE; |
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274 | rtems_semaphore_release(diskdevs_mutex); |
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275 | return rc; |
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276 | } |
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277 | |
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278 | dd->phys_dev = dd; |
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279 | dd->uses = 0; |
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280 | dd->start = 0; |
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281 | dd->size = disk_size; |
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282 | dd->block_size = block_size; |
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283 | dd->block_size_log2 = bs_log2; |
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284 | dd->ioctl = handler; |
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285 | dd->pool = pool; |
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286 | |
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287 | rc = rtems_io_register_name(name, major, minor); |
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288 | |
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289 | if (handler (dd->phys_dev->dev, |
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290 | RTEMS_BLKDEV_CAPABILITIES, |
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291 | &dd->capabilities) < 0) |
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292 | dd->capabilities = 0; |
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293 | |
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294 | diskdevs_protected = FALSE; |
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295 | rtems_semaphore_release(diskdevs_mutex); |
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296 | |
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297 | return rc; |
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298 | } |
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299 | |
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300 | /* rtems_disk_create_log -- |
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301 | * Create logical disk entry. Logical disk is contiguous area on physical |
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302 | * disk. Disk may be splitted to several logical disks in several ways: |
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303 | * manually or using information stored in blocks on physical disk |
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304 | * (DOS-like partition table, BSD disk label, etc). This function usually |
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305 | * invoked from application when application-specific splitting are in use, |
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306 | * or from generic code which handle different logical disk organizations. |
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307 | * This primitive will register device in rtems (invoke |
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308 | * rtems_io_register_name). |
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309 | * |
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310 | * PARAMETERS: |
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311 | * dev - logical device identifier (major, minor numbers) |
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312 | * phys - physical device (block device which holds this logical disk) |
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313 | * identifier |
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314 | * start - starting block number on the physical device |
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315 | * size - logical disk size in blocks |
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316 | * name - logical disk name |
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317 | * |
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318 | * RETURNS: |
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319 | * RTEMS_SUCCESSFUL if logical device successfully added, or error code |
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320 | * if error occured (device already registered, no physical device |
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321 | * exists, logical disk is out of physical disk boundaries, no memory |
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322 | * available). |
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323 | */ |
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324 | rtems_status_code |
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325 | rtems_disk_create_log(dev_t dev, dev_t phys, int start, int size, char *name) |
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326 | { |
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327 | rtems_disk_device *dd; |
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328 | rtems_disk_device *pdd; |
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329 | rtems_status_code rc; |
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330 | rtems_device_major_number major; |
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331 | rtems_device_minor_number minor; |
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332 | |
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333 | rtems_filesystem_split_dev_t (dev, major, minor); |
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334 | |
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335 | rc = rtems_semaphore_obtain(diskdevs_mutex, RTEMS_WAIT, RTEMS_NO_TIMEOUT); |
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336 | if (rc != RTEMS_SUCCESSFUL) |
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337 | return rc; |
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338 | diskdevs_protected = TRUE; |
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339 | |
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340 | pdd = get_disk_entry(phys); |
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341 | if (pdd == NULL) |
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342 | { |
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343 | diskdevs_protected = FALSE; |
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344 | rtems_semaphore_release(diskdevs_mutex); |
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345 | return RTEMS_INVALID_NUMBER; |
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346 | } |
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347 | |
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348 | rc = create_disk(dev, name, &dd); |
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349 | if (rc != RTEMS_SUCCESSFUL) |
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350 | { |
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351 | diskdevs_protected = FALSE; |
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352 | rtems_semaphore_release(diskdevs_mutex); |
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353 | return rc; |
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354 | } |
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355 | |
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356 | dd->phys_dev = pdd; |
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357 | dd->uses = 0; |
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358 | dd->start = start; |
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359 | dd->size = size; |
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360 | dd->block_size = pdd->block_size; |
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361 | dd->block_size_log2 = pdd->block_size_log2; |
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362 | dd->ioctl = pdd->ioctl; |
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363 | |
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364 | rc = rtems_io_register_name(name, major, minor); |
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365 | |
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366 | diskdevs_protected = FALSE; |
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367 | rc = rtems_semaphore_release(diskdevs_mutex); |
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368 | |
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369 | return rc; |
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370 | } |
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371 | |
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372 | /* rtems_disk_delete -- |
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373 | * Delete physical or logical disk device. Device may be deleted if its |
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374 | * use counter (and use counters of all logical devices - if it is |
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375 | * physical device) equal to 0. When physical device deleted, |
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376 | * all logical devices deleted inherently. Appropriate devices removed |
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377 | * from "/dev" filesystem. |
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378 | * |
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379 | * PARAMETERS: |
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380 | * dev - device identifier (major, minor numbers) |
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381 | * |
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382 | * RETURNS: |
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383 | * RTEMS_SUCCESSFUL if block device successfully deleted, or error code |
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384 | * if error occured (device is not defined, device is in use). |
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385 | */ |
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386 | rtems_status_code |
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387 | rtems_disk_delete(dev_t dev) |
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388 | { |
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389 | rtems_status_code rc; |
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390 | int used; |
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391 | rtems_device_major_number maj; |
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392 | rtems_device_minor_number min; |
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393 | |
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394 | rc = rtems_semaphore_obtain(diskdevs_mutex, RTEMS_WAIT, RTEMS_NO_TIMEOUT); |
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395 | if (rc != RTEMS_SUCCESSFUL) |
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396 | return rc; |
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397 | diskdevs_protected = TRUE; |
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398 | |
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399 | /* Check if this device is in use -- calculate usage counter */ |
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400 | used = 0; |
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401 | for (maj = 0; maj < disktab_size; maj++) |
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402 | { |
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403 | rtems_disk_device_table *dtab = disktab + maj; |
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404 | if (dtab != NULL) |
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405 | { |
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406 | for (min = 0; min < dtab->size; min++) |
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407 | { |
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408 | rtems_disk_device *dd = dtab->minor[min]; |
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409 | if ((dd != NULL) && (dd->phys_dev->dev == dev)) |
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410 | used += dd->uses; |
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411 | } |
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412 | } |
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413 | } |
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414 | |
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415 | if (used != 0) |
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416 | { |
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417 | diskdevs_protected = FALSE; |
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418 | rtems_semaphore_release(diskdevs_mutex); |
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419 | return RTEMS_RESOURCE_IN_USE; |
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420 | } |
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421 | |
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422 | /* Delete this device and all of its logical devices */ |
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423 | for (maj = 0; maj < disktab_size; maj++) |
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424 | { |
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425 | rtems_disk_device_table *dtab = disktab +maj; |
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426 | if (dtab != NULL) |
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427 | { |
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428 | for (min = 0; min < dtab->size; min++) |
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429 | { |
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430 | rtems_disk_device *dd = dtab->minor[min]; |
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431 | if ((dd != NULL) && (dd->phys_dev->dev == dev)) |
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432 | { |
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433 | unlink(dd->name); |
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434 | free(dd->name); |
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435 | free(dd); |
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436 | dtab->minor[min] = NULL; |
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437 | } |
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438 | } |
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439 | } |
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440 | } |
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441 | |
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442 | diskdevs_protected = FALSE; |
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443 | rc = rtems_semaphore_release(diskdevs_mutex); |
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444 | return rc; |
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445 | } |
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446 | |
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447 | /* rtems_disk_obtain -- |
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448 | * Find block device descriptor by its device identifier. |
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449 | * |
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450 | * PARAMETERS: |
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451 | * dev - device identifier (major, minor numbers) |
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452 | * |
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453 | * RETURNS: |
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454 | * pointer to the block device descriptor, or NULL if no such device |
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455 | * exists. |
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456 | */ |
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457 | rtems_disk_device * |
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458 | rtems_disk_obtain(dev_t dev) |
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459 | { |
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460 | rtems_interrupt_level level; |
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461 | rtems_disk_device *dd; |
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462 | rtems_status_code rc; |
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463 | |
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464 | rtems_interrupt_disable(level); |
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465 | if (diskdevs_protected) |
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466 | { |
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467 | rtems_interrupt_enable(level); |
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468 | rc = rtems_semaphore_obtain(diskdevs_mutex, RTEMS_WAIT, |
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469 | RTEMS_NO_TIMEOUT); |
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470 | if (rc != RTEMS_SUCCESSFUL) |
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471 | return NULL; |
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472 | diskdevs_protected = TRUE; |
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473 | dd = get_disk_entry(dev); |
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474 | dd->uses++; |
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475 | diskdevs_protected = FALSE; |
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476 | rtems_semaphore_release(diskdevs_mutex); |
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477 | return dd; |
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478 | } |
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479 | else |
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480 | { |
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481 | /* Frequent and quickest case */ |
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482 | dd = get_disk_entry(dev); |
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483 | dd->uses++; |
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484 | rtems_interrupt_enable(level); |
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485 | return dd; |
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486 | } |
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487 | } |
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488 | |
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489 | /* rtems_disk_release -- |
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490 | * Release rtems_disk_device structure (decrement usage counter to 1). |
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491 | * |
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492 | * PARAMETERS: |
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493 | * dd - pointer to disk device structure |
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494 | * |
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495 | * RETURNS: |
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496 | * RTEMS_SUCCESSFUL |
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497 | */ |
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498 | rtems_status_code |
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499 | rtems_disk_release(rtems_disk_device *dd) |
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500 | { |
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501 | rtems_interrupt_level level; |
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502 | rtems_interrupt_disable(level); |
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503 | dd->uses--; |
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504 | rtems_interrupt_enable(level); |
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505 | return RTEMS_SUCCESSFUL; |
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506 | } |
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507 | |
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508 | /* rtems_disk_next -- |
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509 | * Disk device enumerator. Looking for device having device number larger |
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510 | * than dev and return disk device descriptor for it. If there are no |
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511 | * such device, NULL value returned. |
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512 | * |
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513 | * PARAMETERS: |
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514 | * dev - device number (use -1 to start search) |
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515 | * |
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516 | * RETURNS: |
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517 | * Pointer to the disk descriptor for next disk device, or NULL if all |
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518 | * devices enumerated. |
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519 | */ |
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520 | rtems_disk_device * |
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521 | rtems_disk_next(dev_t dev) |
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522 | { |
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523 | rtems_device_major_number major; |
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524 | rtems_device_minor_number minor; |
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525 | rtems_disk_device_table *dtab; |
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526 | |
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527 | dev++; |
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528 | rtems_filesystem_split_dev_t (dev, major, minor); |
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529 | |
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530 | if (major >= disktab_size) |
---|
531 | return NULL; |
---|
532 | |
---|
533 | dtab = disktab + major; |
---|
534 | while (TRUE) |
---|
535 | { |
---|
536 | if ((dtab == NULL) || (minor > dtab->size)) |
---|
537 | { |
---|
538 | major++; minor = 0; |
---|
539 | if (major >= disktab_size) |
---|
540 | return NULL; |
---|
541 | dtab = disktab + major; |
---|
542 | } |
---|
543 | else if (dtab->minor[minor] == NULL) |
---|
544 | { |
---|
545 | minor++; |
---|
546 | } |
---|
547 | else |
---|
548 | return dtab->minor[minor]; |
---|
549 | } |
---|
550 | } |
---|
551 | |
---|
552 | /* rtems_disk_initialize -- |
---|
553 | * Initialization of disk device library (initialize all data structures, |
---|
554 | * etc.) |
---|
555 | * |
---|
556 | * PARAMETERS: |
---|
557 | * none |
---|
558 | * |
---|
559 | * RETURNS: |
---|
560 | * RTEMS_SUCCESSFUL if library initialized, or error code if error |
---|
561 | * occured. |
---|
562 | */ |
---|
563 | rtems_status_code |
---|
564 | rtems_disk_io_initialize(void) |
---|
565 | { |
---|
566 | rtems_status_code rc; |
---|
567 | |
---|
568 | if (disk_io_initialized) |
---|
569 | return RTEMS_SUCCESSFUL; |
---|
570 | |
---|
571 | disktab_size = DISKTAB_INITIAL_SIZE; |
---|
572 | disktab = calloc(disktab_size, sizeof(rtems_disk_device_table)); |
---|
573 | if (disktab == NULL) |
---|
574 | return RTEMS_NO_MEMORY; |
---|
575 | |
---|
576 | diskdevs_protected = FALSE; |
---|
577 | rc = rtems_semaphore_create( |
---|
578 | rtems_build_name('D', 'D', 'E', 'V'), 1, |
---|
579 | RTEMS_FIFO | RTEMS_BINARY_SEMAPHORE | RTEMS_NO_INHERIT_PRIORITY | |
---|
580 | RTEMS_NO_PRIORITY_CEILING | RTEMS_LOCAL, 0, &diskdevs_mutex); |
---|
581 | |
---|
582 | if (rc != RTEMS_SUCCESSFUL) |
---|
583 | { |
---|
584 | free(disktab); |
---|
585 | return rc; |
---|
586 | } |
---|
587 | |
---|
588 | rc = rtems_bdbuf_init(); |
---|
589 | |
---|
590 | if (rc != RTEMS_SUCCESSFUL) |
---|
591 | { |
---|
592 | rtems_semaphore_delete(diskdevs_mutex); |
---|
593 | free(disktab); |
---|
594 | return rc; |
---|
595 | } |
---|
596 | |
---|
597 | disk_io_initialized = 1; |
---|
598 | return RTEMS_SUCCESSFUL; |
---|
599 | } |
---|
600 | |
---|
601 | /* rtems_disk_io_done -- |
---|
602 | * Release all resources allocated for disk device interface. |
---|
603 | * |
---|
604 | * PARAMETERS: |
---|
605 | * none |
---|
606 | * |
---|
607 | * RETURNS: |
---|
608 | * RTEMS_SUCCESSFUL if all resources released, or error code if error |
---|
609 | * occured. |
---|
610 | */ |
---|
611 | rtems_status_code |
---|
612 | rtems_disk_io_done(void) |
---|
613 | { |
---|
614 | rtems_device_major_number maj; |
---|
615 | rtems_device_minor_number min; |
---|
616 | rtems_status_code rc; |
---|
617 | |
---|
618 | /* Free data structures */ |
---|
619 | for (maj = 0; maj < disktab_size; maj++) |
---|
620 | { |
---|
621 | rtems_disk_device_table *dtab = disktab + maj; |
---|
622 | if (dtab != NULL) |
---|
623 | { |
---|
624 | for (min = 0; min < dtab->size; min++) |
---|
625 | { |
---|
626 | rtems_disk_device *dd = dtab->minor[min]; |
---|
627 | unlink(dd->name); |
---|
628 | free(dd->name); |
---|
629 | free(dd); |
---|
630 | } |
---|
631 | free(dtab); |
---|
632 | } |
---|
633 | } |
---|
634 | free(disktab); |
---|
635 | |
---|
636 | rc = rtems_semaphore_delete(diskdevs_mutex); |
---|
637 | |
---|
638 | /* XXX bdbuf should be released too! */ |
---|
639 | disk_io_initialized = 0; |
---|
640 | return rc; |
---|
641 | } |
---|