1 | /** |
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2 | * @file |
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3 | * |
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4 | * Block device management. |
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5 | */ |
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6 | |
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7 | /* |
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8 | * Copyright (C) 2001 OKTET Ltd., St.-Petersburg, Russia |
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9 | * Author: Victor V. Vengerov <vvv@oktet.ru> |
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10 | * |
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11 | * @(#) $Id$ |
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12 | */ |
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13 | |
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14 | #ifndef _RTEMS_BLKDEV_H |
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15 | #define _RTEMS_BLKDEV_H |
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16 | |
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17 | #include <rtems.h> |
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18 | #include <sys/ioctl.h> |
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19 | |
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20 | #ifdef __cplusplus |
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21 | extern "C" { |
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22 | #endif |
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23 | |
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24 | /** |
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25 | * @defgroup rtems_blkdev Block Device Management |
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26 | * |
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27 | * @ingroup rtems_libblock |
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28 | * |
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29 | * Interface between device drivers and the |
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30 | * @ref rtems_bdbuf "block device buffer module". |
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31 | * |
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32 | * The heart of the block device driver is the @ref RTEMS_BLKIO_REQUEST IO |
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33 | * control. This call puts IO @ref rtems_blkdev_request "requests" to the block |
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34 | * device for asynchronous processing. When a driver executes a request, it |
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35 | * invokes the request done callback function to finish the request. |
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36 | * |
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37 | * @{ |
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38 | */ |
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39 | |
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40 | /** |
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41 | * Block device block index type. |
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42 | */ |
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43 | typedef uint32_t rtems_blkdev_bnum; |
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44 | |
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45 | /** |
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46 | * Block device request type. |
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47 | */ |
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48 | typedef enum rtems_blkdev_request_op { |
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49 | RTEMS_BLKDEV_REQ_READ, |
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50 | RTEMS_BLKDEV_REQ_WRITE, |
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51 | RTEMS_BLKDEV_CAPABILITIES |
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52 | } rtems_blkdev_request_op; |
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53 | |
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54 | /** |
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55 | * Only consecutive multi-sector buffer requests are supported. |
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56 | * |
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57 | * This option means the cache will only supply multiple buffers that are |
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58 | * inorder so the ATA multi-sector command for example can be used. This is a |
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59 | * hack to work around the current ATA driver. |
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60 | */ |
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61 | #define RTEMS_BLKDEV_CAP_MULTISECTOR_CONT (1 << 0) |
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62 | |
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63 | /** |
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64 | * Type for block device request done callback function. |
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65 | * |
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66 | * @param arg Argument supplied in @ref rtems_blkdev_request. |
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67 | * @param status Status code for this operation. |
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68 | * @param errno The @c errno value to be passed to the user when status is not |
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69 | * equal to @c RTEMS_SUCCESSFUL. |
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70 | */ |
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71 | typedef void (* rtems_blkdev_request_cb)(void *arg, |
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72 | rtems_status_code status, |
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73 | int error); |
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74 | |
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75 | /** |
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76 | * Block device scatter or gather buffer structure. |
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77 | */ |
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78 | typedef struct rtems_blkdev_sg_buffer { |
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79 | /** |
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80 | * Block index. |
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81 | */ |
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82 | rtems_blkdev_bnum block; |
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83 | |
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84 | /** |
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85 | * Buffer length. |
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86 | */ |
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87 | uint32_t length; |
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88 | |
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89 | /** |
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90 | * Buffer pointer. |
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91 | */ |
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92 | void *buffer; |
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93 | |
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94 | /** |
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95 | * User pointer. |
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96 | */ |
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97 | void *user; |
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98 | } rtems_blkdev_sg_buffer; |
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99 | |
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100 | /** |
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101 | * The block device request structure is used to read or write a number of |
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102 | * blocks from or to the device. |
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103 | */ |
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104 | typedef struct rtems_blkdev_request { |
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105 | /** |
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106 | * Block device operation (read or write). |
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107 | */ |
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108 | rtems_blkdev_request_op req; |
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109 | |
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110 | /** |
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111 | * Request done callback function. |
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112 | */ |
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113 | rtems_blkdev_request_cb req_done; |
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114 | |
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115 | /** |
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116 | * Argument to be passed to callback function. |
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117 | */ |
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118 | void *done_arg; |
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119 | |
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120 | /** |
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121 | * Last IO operation completion status. |
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122 | */ |
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123 | rtems_status_code status; |
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124 | |
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125 | /** |
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126 | * If @c status is not equal to @c RTEMS_SUCCESSFUL, this field contains the |
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127 | * error number. |
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128 | */ |
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129 | int error; |
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130 | |
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131 | /** |
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132 | * Number of blocks for this request. |
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133 | */ |
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134 | uint32_t bufnum; |
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135 | |
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136 | /** |
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137 | * The task requesting the IO operation. |
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138 | */ |
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139 | rtems_id io_task; |
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140 | |
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141 | /** |
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142 | * List of scatter or gather buffers. |
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143 | */ |
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144 | rtems_blkdev_sg_buffer bufs[0]; |
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145 | } rtems_blkdev_request; |
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146 | |
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147 | /** |
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148 | * The start block in a request. |
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149 | * |
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150 | * Only valid if the driver has returned the @ref RTEMS_BLKDEV_CAPABILITIES of |
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151 | * @ref RTEMS_BLKDEV_CAP_MULTISECTOR_CONT. |
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152 | */ |
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153 | #define RTEMS_BLKDEV_START_BLOCK(req) (req->bufs[0].block) |
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154 | |
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155 | /** |
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156 | * @name IO Control Request Codes |
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157 | * |
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158 | * @{ |
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159 | */ |
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160 | |
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161 | #define RTEMS_BLKIO_REQUEST _IOWR('B', 1, rtems_blkdev_request) |
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162 | #define RTEMS_BLKIO_GETBLKSIZE _IO('B', 2) |
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163 | #define RTEMS_BLKIO_GETSIZE _IO('B', 3) |
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164 | #define RTEMS_BLKIO_SYNCDEV _IO('B', 4) |
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165 | |
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166 | /** @} */ |
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167 | |
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168 | /** |
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169 | * The device driver interface conventions suppose that a driver may contain an |
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170 | * initialize, open, close, read, write and IO control entry points. These |
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171 | * primitives (except initialize) can be implemented in a generic fashion based |
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172 | * upon the supplied block device driver IO control handler. Every block device |
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173 | * driver should provide an initialize entry point, which registers the |
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174 | * appropriate IO control handler. |
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175 | */ |
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176 | #define RTEMS_GENERIC_BLOCK_DEVICE_DRIVER_ENTRIES \ |
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177 | .open_entry = rtems_blkdev_generic_open, \ |
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178 | .close_entry = rtems_blkdev_generic_close, \ |
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179 | .read_entry = rtems_blkdev_generic_read, \ |
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180 | .write_entry = rtems_blkdev_generic_write, \ |
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181 | .control_entry = rtems_blkdev_generic_ioctl |
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182 | |
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183 | /** |
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184 | * Generic block device read primitive. |
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185 | * |
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186 | * Implemented using block device buffer management primitives. |
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187 | */ |
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188 | rtems_device_driver |
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189 | rtems_blkdev_generic_read( |
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190 | rtems_device_major_number major, |
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191 | rtems_device_minor_number minor, |
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192 | void * arg |
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193 | ); |
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194 | |
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195 | /** |
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196 | * Generic block device write primitive. |
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197 | * |
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198 | * Implemented using block device buffer management primitives. |
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199 | */ |
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200 | rtems_device_driver |
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201 | rtems_blkdev_generic_write( |
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202 | rtems_device_major_number major, |
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203 | rtems_device_minor_number minor, |
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204 | void * arg |
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205 | ); |
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206 | |
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207 | /** |
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208 | * Generic block device open primitive. |
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209 | * |
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210 | * Implemented using block device buffer management primitives. |
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211 | */ |
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212 | rtems_device_driver |
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213 | rtems_blkdev_generic_open( |
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214 | rtems_device_major_number major, |
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215 | rtems_device_minor_number minor, |
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216 | void * arg |
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217 | ); |
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218 | |
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219 | /** |
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220 | * Generic block device close primitive. |
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221 | * |
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222 | * Implemented using block device buffer management primitives. |
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223 | */ |
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224 | rtems_device_driver |
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225 | rtems_blkdev_generic_close( |
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226 | rtems_device_major_number major, |
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227 | rtems_device_minor_number minor, |
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228 | void * arg |
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229 | ); |
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230 | |
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231 | /** |
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232 | * Generic block device IO control primitive. |
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233 | * |
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234 | * Implemented using block device buffer management primitives. |
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235 | */ |
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236 | rtems_device_driver |
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237 | rtems_blkdev_generic_ioctl( |
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238 | rtems_device_major_number major, |
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239 | rtems_device_minor_number minor, |
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240 | void * arg |
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241 | ); |
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242 | |
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243 | /** @} */ |
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244 | |
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245 | #ifdef __cplusplus |
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246 | } |
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247 | #endif |
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248 | |
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249 | #endif |
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