1 | /** |
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2 | * @file |
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3 | * |
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4 | * @ingroup rtems_disk |
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5 | * |
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6 | * Block device disk management. |
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7 | */ |
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8 | |
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9 | /* |
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10 | * Copyright (C) 2001 OKTET Ltd., St.-Petersburg, Russia |
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11 | * Author: Victor V. Vengerov <vvv@oktet.ru> |
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12 | * |
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13 | * @(#) $Id$ |
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14 | */ |
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15 | |
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16 | #if HAVE_CONFIG_H |
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17 | #include "config.h" |
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18 | #endif |
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19 | |
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20 | #include <rtems.h> |
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21 | #include <rtems/libio.h> |
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22 | #include <stdlib.h> |
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23 | #include <unistd.h> /* unlink */ |
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24 | #include <string.h> |
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25 | |
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26 | #include "rtems/diskdevs.h" |
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27 | #include "rtems/bdbuf.h" |
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28 | |
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29 | #define DISKTAB_INITIAL_SIZE 32 |
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30 | |
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31 | /* Table of disk devices having the same major number */ |
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32 | typedef struct rtems_disk_device_table { |
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33 | rtems_disk_device **minor; /* minor-indexed disk device table */ |
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34 | uint32_t size; /* Number of entries in the table */ |
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35 | } rtems_disk_device_table; |
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36 | |
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37 | /* Pointer to [major].minor[minor] indexed array of disk devices */ |
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38 | static rtems_disk_device_table *disktab; |
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39 | |
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40 | /* Number of allocated entries in disktab table */ |
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41 | static uint32_t disktab_size; |
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42 | |
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43 | /* Mutual exclusion semaphore for disk devices table */ |
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44 | static rtems_id diskdevs_mutex; |
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45 | |
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46 | /* Flag meaning that disk I/O, buffering etc. already has been initialized. */ |
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47 | static bool disk_io_initialized = false; |
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48 | |
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49 | /* diskdevs data structures protection flag. |
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50 | * Normally, only table lookup operations performed. It is quite fast, so |
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51 | * it is possible to done lookups when interrupts are disabled, avoiding |
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52 | * obtaining the semaphore. This flags sets immediately after entering in |
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53 | * mutex-protected section and cleared before leaving this section in |
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54 | * "big" primitives like add/delete new device etc. Lookup function first |
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55 | * disable interrupts and check this flag. If it is set, lookup function |
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56 | * will be blocked on semaphore and lookup operation will be performed in |
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57 | * semaphore-protected code. If it is not set (very-very frequent case), |
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58 | * we can do lookup safely, enable interrupts and return result. |
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59 | */ |
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60 | static volatile bool diskdevs_protected; |
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61 | |
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62 | /* create_disk_entry -- |
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63 | * Return pointer to the disk_entry structure for the specified device, or |
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64 | * create one if it is not exists. |
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65 | * |
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66 | * PARAMETERS: |
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67 | * dev - device id (major, minor) |
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68 | * |
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69 | * RETURNS: |
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70 | * pointer to the disk device descriptor entry, or NULL if no memory |
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71 | * available for its creation. |
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72 | */ |
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73 | static rtems_disk_device * |
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74 | create_disk_entry(dev_t dev) |
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75 | { |
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76 | rtems_device_major_number major; |
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77 | rtems_device_minor_number minor; |
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78 | rtems_disk_device **d; |
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79 | |
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80 | rtems_filesystem_split_dev_t (dev, major, minor); |
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81 | |
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82 | if (major >= disktab_size) |
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83 | { |
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84 | rtems_disk_device_table *p; |
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85 | uint32_t newsize; |
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86 | uint32_t i; |
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87 | newsize = disktab_size * 2; |
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88 | if (major >= newsize) |
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89 | newsize = major + 1; |
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90 | p = realloc(disktab, sizeof(rtems_disk_device_table) * newsize); |
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91 | if (p == NULL) |
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92 | return NULL; |
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93 | disktab = p; |
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94 | p += disktab_size; |
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95 | for (i = disktab_size; i < newsize; i++, p++) |
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96 | { |
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97 | p->minor = NULL; |
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98 | p->size = 0; |
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99 | } |
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100 | disktab_size = newsize; |
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101 | } |
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102 | |
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103 | if ((disktab[major].minor == NULL) || |
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104 | (minor >= disktab[major].size)) |
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105 | { |
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106 | uint32_t newsize; |
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107 | rtems_disk_device **p; |
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108 | uint32_t i; |
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109 | uint32_t s = disktab[major].size; |
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110 | |
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111 | if (s == 0) |
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112 | newsize = DISKTAB_INITIAL_SIZE; |
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113 | else |
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114 | newsize = s * 2; |
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115 | if (minor >= newsize) |
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116 | newsize = minor + 1; |
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117 | |
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118 | p = realloc(disktab[major].minor, |
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119 | sizeof(rtems_disk_device *) * newsize); |
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120 | if (p == NULL) |
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121 | return NULL; |
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122 | disktab[major].minor = p; |
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123 | p += s; |
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124 | for (i = s; i < newsize; i++, p++) |
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125 | *p = NULL; |
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126 | disktab[major].size = newsize; |
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127 | } |
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128 | |
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129 | d = disktab[major].minor + minor; |
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130 | if (*d == NULL) |
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131 | { |
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132 | *d = calloc(1, sizeof(rtems_disk_device)); |
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133 | } |
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134 | return *d; |
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135 | } |
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136 | |
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137 | /* get_disk_entry -- |
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138 | * Get disk device descriptor by device number. |
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139 | * |
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140 | * PARAMETERS: |
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141 | * dev - block device number |
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142 | * |
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143 | * RETURNS: |
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144 | * Pointer to the disk device descriptor corresponding to the specified |
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145 | * device number, or NULL if disk device with such number not exists. |
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146 | */ |
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147 | static rtems_disk_device * |
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148 | get_disk_entry(dev_t dev) |
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149 | { |
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150 | rtems_device_major_number major; |
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151 | rtems_device_minor_number minor; |
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152 | rtems_disk_device_table *dtab; |
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153 | |
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154 | rtems_filesystem_split_dev_t (dev, major, minor); |
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155 | |
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156 | if ((major >= disktab_size) || (disktab == NULL)) |
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157 | return NULL; |
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158 | |
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159 | dtab = disktab + major; |
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160 | |
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161 | if ((minor >= dtab->size) || (dtab->minor == NULL)) |
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162 | return NULL; |
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163 | |
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164 | return dtab->minor[minor]; |
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165 | } |
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166 | |
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167 | /* create_disk -- |
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168 | * Check that disk entry for specified device number is not defined |
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169 | * and create it. |
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170 | * |
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171 | * PARAMETERS: |
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172 | * dev - device identifier (major, minor numbers) |
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173 | * name - character name of device (e.g. /dev/hda) |
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174 | * disdev - placeholder for pointer to created disk descriptor |
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175 | * |
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176 | * RETURNS: |
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177 | * RTEMS_SUCCESSFUL if disk entry successfully created, or |
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178 | * error code if error occured (device already registered, |
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179 | * no memory available). |
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180 | */ |
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181 | static rtems_status_code |
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182 | create_disk(dev_t dev, const char *name, rtems_disk_device **diskdev) |
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183 | { |
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184 | rtems_disk_device *dd; |
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185 | char *n; |
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186 | |
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187 | dd = get_disk_entry(dev); |
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188 | if (dd != NULL) |
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189 | { |
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190 | return RTEMS_RESOURCE_IN_USE; |
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191 | } |
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192 | |
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193 | if (name == NULL) |
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194 | { |
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195 | n = NULL; |
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196 | } |
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197 | else |
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198 | { |
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199 | int nlen = strlen(name) + 1; |
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200 | n = malloc(nlen); |
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201 | if (n == NULL) |
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202 | return RTEMS_NO_MEMORY; |
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203 | strncpy(n, name, nlen); |
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204 | } |
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205 | |
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206 | dd = create_disk_entry(dev); |
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207 | if (dd == NULL) |
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208 | { |
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209 | free(n); |
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210 | return RTEMS_NO_MEMORY; |
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211 | } |
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212 | |
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213 | dd->dev = dev; |
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214 | dd->name = n; |
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215 | |
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216 | *diskdev = dd; |
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217 | |
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218 | return RTEMS_SUCCESSFUL; |
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219 | } |
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220 | |
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221 | rtems_status_code rtems_disk_create_phys( |
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222 | dev_t dev, |
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223 | uint32_t block_size, |
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224 | rtems_blkdev_bnum disk_size, |
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225 | rtems_block_device_ioctl handler, |
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226 | const char *name |
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227 | ) |
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228 | { |
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229 | rtems_disk_device *dd; |
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230 | rtems_status_code rc; |
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231 | rtems_device_major_number major; |
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232 | rtems_device_minor_number minor; |
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233 | |
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234 | rtems_filesystem_split_dev_t (dev, major, minor); |
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235 | |
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236 | rc = rtems_semaphore_obtain(diskdevs_mutex, RTEMS_WAIT, RTEMS_NO_TIMEOUT); |
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237 | if (rc != RTEMS_SUCCESSFUL) |
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238 | return rc; |
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239 | diskdevs_protected = true; |
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240 | |
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241 | rc = create_disk(dev, name, &dd); |
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242 | if (rc != RTEMS_SUCCESSFUL) |
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243 | { |
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244 | diskdevs_protected = false; |
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245 | rtems_semaphore_release(diskdevs_mutex); |
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246 | return rc; |
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247 | } |
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248 | |
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249 | dd->phys_dev = dd; |
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250 | dd->uses = 0; |
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251 | dd->start = 0; |
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252 | dd->size = disk_size; |
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253 | dd->block_size = dd->media_block_size = block_size; |
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254 | dd->ioctl = handler; |
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255 | |
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256 | rc = rtems_io_register_name(name, major, minor); |
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257 | |
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258 | if (handler (dd->phys_dev->dev, |
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259 | RTEMS_BLKDEV_CAPABILITIES, |
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260 | &dd->capabilities) < 0) |
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261 | dd->capabilities = 0; |
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262 | |
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263 | diskdevs_protected = false; |
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264 | rtems_semaphore_release(diskdevs_mutex); |
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265 | |
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266 | return rc; |
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267 | } |
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268 | |
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269 | rtems_status_code rtems_disk_create_log( |
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270 | dev_t dev, |
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271 | dev_t phys, |
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272 | rtems_blkdev_bnum start, |
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273 | rtems_blkdev_bnum size, |
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274 | const char *name |
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275 | ) |
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276 | { |
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277 | rtems_disk_device *dd = NULL; |
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278 | rtems_disk_device *pdd = NULL; |
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279 | rtems_status_code rc = RTEMS_SUCCESSFUL; |
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280 | rtems_device_major_number major = 0; |
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281 | rtems_device_minor_number minor = 0; |
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282 | rtems_blkdev_bnum end = start + size; |
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283 | |
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284 | rtems_filesystem_split_dev_t (dev, major, minor); |
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285 | |
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286 | rc = rtems_semaphore_obtain(diskdevs_mutex, RTEMS_WAIT, RTEMS_NO_TIMEOUT); |
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287 | if (rc != RTEMS_SUCCESSFUL) { |
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288 | return rc; |
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289 | } |
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290 | |
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291 | diskdevs_protected = true; |
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292 | |
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293 | pdd = get_disk_entry(phys); |
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294 | if ( |
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295 | pdd == NULL |
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296 | || pdd != pdd->phys_dev |
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297 | || start >= pdd->size |
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298 | || end <= start |
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299 | || end > pdd->size |
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300 | ) { |
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301 | diskdevs_protected = false; |
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302 | rtems_semaphore_release(diskdevs_mutex); |
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303 | return RTEMS_INVALID_NUMBER; |
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304 | } |
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305 | |
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306 | rc = create_disk(dev, name, &dd); |
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307 | if (rc != RTEMS_SUCCESSFUL) { |
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308 | diskdevs_protected = false; |
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309 | rtems_semaphore_release(diskdevs_mutex); |
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310 | return rc; |
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311 | } |
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312 | |
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313 | dd->phys_dev = pdd; |
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314 | dd->uses = 0; |
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315 | dd->start = start; |
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316 | dd->size = size; |
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317 | dd->block_size = pdd->block_size; |
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318 | dd->ioctl = pdd->ioctl; |
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319 | |
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320 | rc = rtems_io_register_name(name, major, minor); |
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321 | |
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322 | diskdevs_protected = false; |
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323 | rc = rtems_semaphore_release(diskdevs_mutex); |
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324 | |
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325 | return rc; |
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326 | } |
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327 | |
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328 | rtems_status_code |
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329 | rtems_disk_delete(dev_t dev) |
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330 | { |
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331 | rtems_status_code rc = RTEMS_SUCCESSFUL; |
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332 | rtems_device_major_number maj = 0; |
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333 | rtems_device_minor_number min = 0; |
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334 | rtems_disk_device *dd = NULL; |
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335 | bool physical_disk = true; |
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336 | |
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337 | rc = rtems_semaphore_obtain(diskdevs_mutex, RTEMS_WAIT, RTEMS_NO_TIMEOUT); |
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338 | if (rc != RTEMS_SUCCESSFUL) { |
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339 | return rc; |
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340 | } |
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341 | diskdevs_protected = true; |
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342 | |
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343 | /* Check if we have a physical or logical disk */ |
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344 | dd = get_disk_entry(dev); |
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345 | if (dd == NULL) { |
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346 | return RTEMS_INVALID_NUMBER; |
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347 | } |
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348 | physical_disk = dd->phys_dev == dd; |
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349 | |
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350 | if (physical_disk) { |
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351 | unsigned used = 0; |
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352 | |
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353 | /* Check if this device is in use -- calculate usage counter */ |
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354 | for (maj = 0; maj < disktab_size; maj++) { |
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355 | rtems_disk_device_table *dtab = disktab + maj; |
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356 | if (dtab != NULL) { |
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357 | for (min = 0; min < dtab->size; min++) { |
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358 | dd = dtab->minor[min]; |
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359 | if ((dd != NULL) && (dd->phys_dev->dev == dev)) { |
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360 | used += dd->uses; |
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361 | } |
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362 | } |
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363 | } |
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364 | } |
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365 | |
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366 | if (used != 0) { |
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367 | diskdevs_protected = false; |
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368 | rtems_semaphore_release(diskdevs_mutex); |
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369 | return RTEMS_RESOURCE_IN_USE; |
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370 | } |
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371 | |
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372 | /* Delete this device and all of its logical devices */ |
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373 | for (maj = 0; maj < disktab_size; maj++) { |
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374 | rtems_disk_device_table *dtab = disktab + maj; |
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375 | if (dtab != NULL) { |
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376 | for (min = 0; min < dtab->size; min++) { |
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377 | dd = dtab->minor[min]; |
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378 | if ((dd != NULL) && (dd->phys_dev->dev == dev)) { |
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379 | unlink(dd->name); |
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380 | free(dd->name); |
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381 | free(dd); |
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382 | dtab->minor[min] = NULL; |
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383 | } |
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384 | } |
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385 | } |
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386 | } |
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387 | } else { |
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388 | rtems_filesystem_split_dev_t(dev, maj, min); |
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389 | disktab[maj].minor[min] = NULL; |
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390 | unlink(dd->name); |
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391 | free(dd->name); |
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392 | free(dd); |
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393 | } |
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394 | |
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395 | diskdevs_protected = false; |
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396 | rc = rtems_semaphore_release(diskdevs_mutex); |
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397 | return rc; |
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398 | } |
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399 | |
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400 | rtems_disk_device * |
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401 | rtems_disk_obtain(dev_t dev) |
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402 | { |
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403 | rtems_interrupt_level level; |
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404 | rtems_disk_device *dd; |
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405 | rtems_status_code rc; |
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406 | |
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407 | rtems_interrupt_disable(level); |
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408 | if (diskdevs_protected) |
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409 | { |
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410 | rtems_interrupt_enable(level); |
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411 | rc = rtems_semaphore_obtain(diskdevs_mutex, RTEMS_WAIT, |
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412 | RTEMS_NO_TIMEOUT); |
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413 | if (rc != RTEMS_SUCCESSFUL) |
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414 | return NULL; |
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415 | diskdevs_protected = true; |
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416 | dd = get_disk_entry(dev); |
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417 | dd->uses++; |
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418 | diskdevs_protected = false; |
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419 | rtems_semaphore_release(diskdevs_mutex); |
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420 | return dd; |
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421 | } |
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422 | else |
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423 | { |
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424 | /* Frequent and quickest case */ |
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425 | dd = get_disk_entry(dev); |
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426 | dd->uses++; |
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427 | rtems_interrupt_enable(level); |
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428 | return dd; |
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429 | } |
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430 | } |
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431 | |
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432 | rtems_status_code |
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433 | rtems_disk_release(rtems_disk_device *dd) |
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434 | { |
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435 | rtems_interrupt_level level; |
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436 | rtems_interrupt_disable(level); |
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437 | dd->uses--; |
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438 | rtems_interrupt_enable(level); |
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439 | return RTEMS_SUCCESSFUL; |
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440 | } |
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441 | |
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442 | rtems_disk_device * |
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443 | rtems_disk_next(dev_t dev) |
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444 | { |
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445 | rtems_device_major_number major; |
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446 | rtems_device_minor_number minor; |
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447 | rtems_disk_device_table *dtab; |
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448 | |
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449 | dev++; |
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450 | rtems_filesystem_split_dev_t (dev, major, minor); |
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451 | |
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452 | if (major >= disktab_size) |
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453 | return NULL; |
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454 | |
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455 | dtab = disktab + major; |
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456 | while (true) |
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457 | { |
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458 | if ((dtab == NULL) || (minor > dtab->size)) |
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459 | { |
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460 | major++; minor = 0; |
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461 | if (major >= disktab_size) |
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462 | return NULL; |
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463 | dtab = disktab + major; |
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464 | } |
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465 | else if (dtab->minor[minor] == NULL) |
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466 | { |
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467 | minor++; |
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468 | } |
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469 | else |
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470 | return dtab->minor[minor]; |
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471 | } |
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472 | } |
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473 | |
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474 | rtems_status_code |
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475 | rtems_disk_io_initialize(void) |
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476 | { |
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477 | rtems_status_code rc; |
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478 | |
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479 | if (disk_io_initialized) |
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480 | return RTEMS_SUCCESSFUL; |
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481 | |
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482 | disktab_size = DISKTAB_INITIAL_SIZE; |
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483 | disktab = calloc(disktab_size, sizeof(rtems_disk_device_table)); |
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484 | if (disktab == NULL) |
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485 | return RTEMS_NO_MEMORY; |
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486 | |
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487 | diskdevs_protected = false; |
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488 | rc = rtems_semaphore_create( |
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489 | rtems_build_name('D', 'D', 'E', 'V'), 1, |
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490 | RTEMS_FIFO | RTEMS_BINARY_SEMAPHORE | RTEMS_NO_INHERIT_PRIORITY | |
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491 | RTEMS_NO_PRIORITY_CEILING | RTEMS_LOCAL, 0, &diskdevs_mutex); |
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492 | |
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493 | if (rc != RTEMS_SUCCESSFUL) |
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494 | { |
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495 | free(disktab); |
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496 | return rc; |
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497 | } |
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498 | |
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499 | rc = rtems_bdbuf_init(); |
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500 | |
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501 | if (rc != RTEMS_SUCCESSFUL) |
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502 | { |
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503 | rtems_semaphore_delete(diskdevs_mutex); |
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504 | free(disktab); |
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505 | return rc; |
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506 | } |
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507 | |
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508 | disk_io_initialized = 1; |
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509 | return RTEMS_SUCCESSFUL; |
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510 | } |
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511 | |
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512 | rtems_status_code |
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513 | rtems_disk_io_done(void) |
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514 | { |
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515 | rtems_device_major_number maj; |
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516 | rtems_device_minor_number min; |
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517 | rtems_status_code rc; |
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518 | |
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519 | /* Free data structures */ |
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520 | for (maj = 0; maj < disktab_size; maj++) |
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521 | { |
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522 | rtems_disk_device_table *dtab = disktab + maj; |
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523 | if (dtab != NULL) |
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524 | { |
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525 | for (min = 0; min < dtab->size; min++) |
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526 | { |
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527 | rtems_disk_device *dd = dtab->minor[min]; |
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528 | unlink(dd->name); |
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529 | free(dd->name); |
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530 | free(dd); |
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531 | } |
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532 | free(dtab); |
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533 | } |
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534 | } |
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535 | free(disktab); |
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536 | |
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537 | rc = rtems_semaphore_delete(diskdevs_mutex); |
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538 | |
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539 | disk_io_initialized = 0; |
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540 | return rc; |
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541 | } |
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