root / prex-0.9.0 / sys / kern / device.c @ 03e9c04a
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1 | 03e9c04a | Brad Neuman | /*-
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2 | * Copyright (c) 2005-2009, Kohsuke Ohtani
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3 | * All rights reserved.
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4 | *
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5 | * Redistribution and use in source and binary forms, with or without
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6 | * modification, are permitted provided that the following conditions
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7 | * are met:
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8 | * 1. Redistributions of source code must retain the above copyright
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9 | * notice, this list of conditions and the following disclaimer.
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10 | * 2. Redistributions in binary form must reproduce the above copyright
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11 | * notice, this list of conditions and the following disclaimer in the
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12 | * documentation and/or other materials provided with the distribution.
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13 | * 3. Neither the name of the author nor the names of any co-contributors
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14 | * may be used to endorse or promote products derived from this software
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15 | * without specific prior written permission.
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16 | *
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17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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18 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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19 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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20 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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21 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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22 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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23 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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24 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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25 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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26 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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27 | * SUCH DAMAGE.
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28 | */
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29 | |||
30 | /*
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31 | * device.c - device I/O support routines
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32 | */
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33 | |||
34 | /**
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35 | * The device_* system calls are interfaces to access the specific
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36 | * device object which is handled by the related device driver.
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37 | *
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38 | * The routines in this moduile have the following role:
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39 | * - Manage the name space for device objects.
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40 | * - Forward user I/O requests to the drivers with minimum check.
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41 | * - Provide the table for the Driver-Kernel Interface.
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42 | */
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43 | |||
44 | #include <kernel.h> |
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45 | #include <irq.h> |
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46 | #include <kmem.h> |
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47 | #include <task.h> |
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48 | #include <timer.h> |
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49 | #include <page.h> |
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50 | #include <sched.h> |
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51 | #include <exception.h> |
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52 | #include <vm.h> |
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53 | #include <device.h> |
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54 | #include <system.h> |
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55 | #include <hal.h> |
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56 | |||
57 | /* forward declarations */
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58 | static device_t device_create(struct driver *, const char *, int); |
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59 | static int device_destroy(device_t); |
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60 | static device_t device_lookup(const char *); |
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61 | static int device_valid(device_t); |
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62 | static int device_reference(device_t); |
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63 | static void device_release(device_t); |
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64 | static void *device_private(device_t); |
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65 | static int device_control(device_t, u_long, void *); |
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66 | static int device_broadcast(u_long, void *, int); |
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67 | |||
68 | #define DKIENT(func) (dkifn_t)(func)
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69 | |||
70 | /*
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71 | * Driver-Kernel Interface (DKI)
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72 | */
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73 | static const dkifn_t dkient[] = { |
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74 | /* 0 */ DKIENT(copyin),
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75 | /* 1 */ DKIENT(copyout),
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76 | /* 2 */ DKIENT(copyinstr),
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77 | /* 3 */ DKIENT(kmem_alloc),
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78 | /* 4 */ DKIENT(kmem_free),
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79 | /* 5 */ DKIENT(kmem_map),
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80 | /* 6 */ DKIENT(page_alloc),
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81 | /* 7 */ DKIENT(page_free),
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82 | /* 8 */ DKIENT(page_reserve),
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83 | /* 9 */ DKIENT(irq_attach),
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84 | /* 10 */ DKIENT(irq_detach),
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85 | /* 11 */ DKIENT(spl0),
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86 | /* 12 */ DKIENT(splhigh),
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87 | /* 13 */ DKIENT(splx),
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88 | /* 14 */ DKIENT(timer_callout),
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89 | /* 15 */ DKIENT(timer_stop),
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90 | /* 16 */ DKIENT(timer_delay),
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91 | /* 17 */ DKIENT(timer_ticks),
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92 | /* 18 */ DKIENT(sched_lock),
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93 | /* 19 */ DKIENT(sched_unlock),
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94 | /* 20 */ DKIENT(sched_tsleep),
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95 | /* 21 */ DKIENT(sched_wakeup),
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96 | /* 22 */ DKIENT(sched_dpc),
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97 | /* 23 */ DKIENT(task_capable),
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98 | /* 24 */ DKIENT(exception_post),
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99 | /* 25 */ DKIENT(device_create),
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100 | /* 26 */ DKIENT(device_destroy),
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101 | /* 27 */ DKIENT(device_lookup),
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102 | /* 28 */ DKIENT(device_control),
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103 | /* 29 */ DKIENT(device_broadcast),
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104 | /* 30 */ DKIENT(device_private),
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105 | /* 31 */ DKIENT(machine_bootinfo),
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106 | /* 32 */ DKIENT(machine_powerdown),
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107 | /* 33 */ DKIENT(sysinfo),
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108 | #ifdef DEBUG
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109 | /* 34 */ DKIENT(panic),
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110 | /* 35 */ DKIENT(printf),
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111 | /* 36 */ DKIENT(dbgctl),
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112 | #else
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113 | /* 34 */ DKIENT(machine_abort),
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114 | /* 35 */ DKIENT(sys_nosys),
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115 | /* 36 */ DKIENT(sys_nosys),
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116 | #endif
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117 | }; |
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118 | |||
119 | /* list head of the devices */
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120 | static struct device *device_list = NULL; |
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121 | |||
122 | /*
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123 | * device_create - create new device object.
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124 | *
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125 | * A device object is created by the device driver to provide
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126 | * I/O services to applications. Returns device ID on
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127 | * success, or 0 on failure.
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128 | */
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129 | static device_t
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130 | device_create(struct driver *drv, const char *name, int flags) |
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131 | { |
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132 | device_t dev; |
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133 | size_t len; |
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134 | void *private = NULL; |
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135 | |||
136 | ASSERT(drv != NULL);
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137 | |||
138 | /* Check the length of name. */
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139 | len = strnlen(name, MAXDEVNAME); |
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140 | if (len == 0 || len >= MAXDEVNAME) |
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141 | return NULL; |
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142 | |||
143 | sched_lock(); |
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144 | |||
145 | /* Check if specified name is already used. */
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146 | if (device_lookup(name) != NULL) |
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147 | panic("duplicate device");
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148 | |||
149 | /*
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150 | * Allocate a device structure and device private data.
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151 | */
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152 | if ((dev = kmem_alloc(sizeof(*dev))) == NULL) |
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153 | panic("device_create");
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154 | |||
155 | if (drv->devsz != 0) { |
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156 | if ((private = kmem_alloc(drv->devsz)) == NULL) |
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157 | panic("devsz");
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158 | memset(private, 0, drv->devsz);
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159 | } |
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160 | strlcpy(dev->name, name, len + 1);
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161 | dev->driver = drv; |
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162 | dev->flags = flags; |
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163 | dev->active = 1;
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164 | dev->refcnt = 1;
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165 | dev->private = private; |
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166 | dev->next = device_list; |
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167 | device_list = dev; |
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168 | |||
169 | sched_unlock(); |
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170 | return dev;
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171 | } |
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172 | |||
173 | /*
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174 | * Destroy a device object. If some other threads still
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175 | * refer the target device, the destroy operation will be
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176 | * pending until its reference count becomes 0.
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177 | */
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178 | static int |
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179 | device_destroy(device_t dev) |
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180 | { |
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181 | |||
182 | sched_lock(); |
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183 | if (!device_valid(dev)) {
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184 | sched_unlock(); |
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185 | return ENODEV;
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186 | } |
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187 | dev->active = 0;
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188 | device_release(dev); |
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189 | sched_unlock(); |
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190 | return 0; |
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191 | } |
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192 | |||
193 | /*
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194 | * Look up a device object by device name.
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195 | */
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196 | static device_t
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197 | device_lookup(const char *name) |
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198 | { |
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199 | device_t dev; |
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200 | |||
201 | for (dev = device_list; dev != NULL; dev = dev->next) { |
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202 | if (!strncmp(dev->name, name, MAXDEVNAME))
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203 | return dev;
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204 | } |
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205 | return NULL; |
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206 | } |
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207 | |||
208 | /*
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209 | * Return device's private data.
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210 | */
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211 | static void * |
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212 | device_private(device_t dev) |
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213 | { |
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214 | ASSERT(dev != NULL);
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215 | ASSERT(dev->private != NULL);
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216 | |||
217 | return dev->private;
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218 | } |
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219 | |||
220 | /*
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221 | * Return true if specified device is valid.
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222 | */
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223 | static int |
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224 | device_valid(device_t dev) |
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225 | { |
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226 | device_t tmp; |
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227 | int found = 0; |
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228 | |||
229 | for (tmp = device_list; tmp != NULL; tmp = tmp->next) { |
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230 | if (tmp == dev) {
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231 | found = 1;
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232 | break;
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233 | } |
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234 | } |
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235 | if (found && dev->active)
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236 | return 1; |
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237 | return 0; |
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238 | } |
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239 | |||
240 | /*
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241 | * Increment the reference count on an active device.
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242 | */
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243 | static int |
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244 | device_reference(device_t dev) |
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245 | { |
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246 | |||
247 | sched_lock(); |
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248 | if (!device_valid(dev)) {
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249 | sched_unlock(); |
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250 | return ENODEV;
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251 | } |
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252 | if (!task_capable(CAP_RAWIO)) {
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253 | sched_unlock(); |
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254 | return EPERM;
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255 | } |
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256 | dev->refcnt++; |
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257 | sched_unlock(); |
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258 | return 0; |
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259 | } |
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260 | |||
261 | /*
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262 | * Decrement the reference count on a device. If the reference
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263 | * count becomes zero, we can release the resource for the device.
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264 | */
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265 | static void |
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266 | device_release(device_t dev) |
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267 | { |
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268 | device_t *tmp; |
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269 | |||
270 | sched_lock(); |
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271 | if (--dev->refcnt > 0) { |
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272 | sched_unlock(); |
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273 | return;
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274 | } |
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275 | /*
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276 | * No more references - we can remove the device.
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277 | */
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278 | for (tmp = &device_list; *tmp; tmp = &(*tmp)->next) {
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279 | if (*tmp == dev) {
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280 | *tmp = dev->next; |
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281 | break;
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282 | } |
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283 | } |
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284 | kmem_free(dev); |
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285 | sched_unlock(); |
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286 | } |
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287 | |||
288 | /*
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289 | * device_open - open the specified device.
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290 | *
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291 | * Even if the target driver does not have an open
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292 | * routine, this function does not return an error. By
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293 | * using this mechanism, an application can check whether
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294 | * the specific device exists or not. The open mode
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295 | * should be handled by an each device driver if it is
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296 | * needed.
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297 | */
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298 | int
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299 | device_open(const char *name, int mode, device_t *devp) |
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300 | { |
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301 | struct devops *ops;
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302 | device_t dev; |
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303 | char str[MAXDEVNAME];
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304 | int error;
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305 | |||
306 | error = copyinstr(name, str, MAXDEVNAME); |
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307 | if (error)
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308 | return error;
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309 | |||
310 | sched_lock(); |
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311 | if ((dev = device_lookup(str)) == NULL) { |
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312 | sched_unlock(); |
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313 | return ENXIO;
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314 | } |
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315 | error = device_reference(dev); |
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316 | if (error) {
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317 | sched_unlock(); |
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318 | return error;
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319 | } |
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320 | sched_unlock(); |
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321 | |||
322 | ops = dev->driver->devops; |
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323 | ASSERT(ops->open != NULL);
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324 | error = (*ops->open)(dev, mode); |
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325 | if (!error)
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326 | error = copyout(&dev, devp, sizeof(dev));
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327 | |||
328 | device_release(dev); |
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329 | return error;
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330 | } |
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331 | |||
332 | /*
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333 | * device_close - close a device.
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334 | *
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335 | * Even if the target driver does not have close routine,
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336 | * this function does not return any errors.
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337 | */
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338 | int
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339 | device_close(device_t dev) |
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340 | { |
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341 | struct devops *ops;
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342 | int error;
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343 | |||
344 | if ((error = device_reference(dev)) != 0) |
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345 | return error;
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346 | |||
347 | ops = dev->driver->devops; |
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348 | ASSERT(ops->close != NULL);
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349 | error = (*ops->close)(dev); |
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350 | |||
351 | device_release(dev); |
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352 | return error;
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353 | } |
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354 | |||
355 | /*
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356 | * device_read - read from a device.
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357 | *
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358 | * Actual read count is set in "nbyte" as return.
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359 | * Note: The size of one block is device dependent.
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360 | */
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361 | int
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362 | device_read(device_t dev, void *buf, size_t *nbyte, int blkno) |
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363 | { |
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364 | struct devops *ops;
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365 | size_t count; |
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366 | int error;
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367 | |||
368 | if (!user_area(buf))
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369 | return EFAULT;
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370 | |||
371 | if ((error = device_reference(dev)) != 0) |
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372 | return error;
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373 | |||
374 | if (copyin(nbyte, &count, sizeof(count))) { |
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375 | device_release(dev); |
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376 | return EFAULT;
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377 | } |
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378 | |||
379 | ops = dev->driver->devops; |
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380 | ASSERT(ops->read != NULL);
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381 | error = (*ops->read)(dev, buf, &count, blkno); |
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382 | if (!error)
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383 | error = copyout(&count, nbyte, sizeof(count));
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384 | |||
385 | device_release(dev); |
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386 | return error;
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387 | } |
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388 | |||
389 | /*
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390 | * device_write - write to a device.
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391 | *
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392 | * Actual write count is set in "nbyte" as return.
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393 | */
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394 | int
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395 | device_write(device_t dev, void *buf, size_t *nbyte, int blkno) |
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396 | { |
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397 | struct devops *ops;
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398 | size_t count; |
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399 | int error;
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400 | |||
401 | if (!user_area(buf))
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402 | return EFAULT;
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403 | |||
404 | if ((error = device_reference(dev)) != 0) |
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405 | return error;
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406 | |||
407 | if (copyin(nbyte, &count, sizeof(count))) { |
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408 | device_release(dev); |
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409 | return EFAULT;
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410 | } |
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411 | |||
412 | ops = dev->driver->devops; |
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413 | ASSERT(ops->write != NULL);
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414 | error = (*ops->write)(dev, buf, &count, blkno); |
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415 | if (!error)
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416 | error = copyout(&count, nbyte, sizeof(count));
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417 | |||
418 | device_release(dev); |
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419 | return error;
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420 | } |
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421 | |||
422 | /*
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423 | * device_ioctl - I/O control request.
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424 | *
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425 | * A command and its argument are completely device dependent.
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426 | * The ioctl routine of each driver must validate the user buffer
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427 | * pointed by the arg value.
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428 | */
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429 | int
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430 | device_ioctl(device_t dev, u_long cmd, void *arg)
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431 | { |
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432 | struct devops *ops;
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433 | int error;
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434 | |||
435 | if ((error = device_reference(dev)) != 0) |
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436 | return error;
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437 | |||
438 | ops = dev->driver->devops; |
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439 | ASSERT(ops->ioctl != NULL);
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440 | error = (*ops->ioctl)(dev, cmd, arg); |
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441 | |||
442 | device_release(dev); |
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443 | return error;
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444 | } |
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445 | |||
446 | /*
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447 | * Device control - devctl is similar to ioctl, but is invoked from
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448 | * other device driver rather than from user application.
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449 | */
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450 | static int |
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451 | device_control(device_t dev, u_long cmd, void *arg)
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452 | { |
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453 | struct devops *ops;
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454 | int error;
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455 | |||
456 | ASSERT(dev != NULL);
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457 | |||
458 | sched_lock(); |
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459 | ops = dev->driver->devops; |
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460 | ASSERT(ops->devctl != NULL);
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461 | error = (*ops->devctl)(dev, cmd, arg); |
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462 | sched_unlock(); |
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463 | return error;
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464 | } |
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465 | |||
466 | /*
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467 | * device_broadcast - broadcast devctl command to all device objects.
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468 | *
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469 | * If "force" argument is true, we will continue command
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470 | * notification even if some driver returns an error. In this
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471 | * case, this routine returns EIO error if at least one driver
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472 | * returns an error.
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473 | *
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474 | * If force argument is false, a kernel stops the command processing
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475 | * when at least one driver returns an error. In this case,
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476 | * device_broadcast will return the error code which is returned
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477 | * by the driver.
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478 | */
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479 | static int |
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480 | device_broadcast(u_long cmd, void *arg, int force) |
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481 | { |
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482 | device_t dev; |
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483 | struct devops *ops;
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484 | int error, retval = 0; |
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485 | |||
486 | sched_lock(); |
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487 | |||
488 | for (dev = device_list; dev != NULL; dev = dev->next) { |
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489 | /*
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490 | * Call driver's devctl() routine.
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491 | */
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492 | ops = dev->driver->devops; |
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493 | if (ops == NULL) |
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494 | continue;
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495 | |||
496 | ASSERT(ops->devctl != NULL);
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497 | error = (*ops->devctl)(dev, cmd, arg); |
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498 | if (error) {
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499 | DPRINTF(("%s returns error=%d for cmd=%ld\n",
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500 | dev->name, error, cmd)); |
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501 | if (force)
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502 | retval = EIO; |
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503 | else {
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504 | retval = error; |
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505 | break;
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506 | } |
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507 | } |
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508 | } |
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509 | sched_unlock(); |
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510 | return retval;
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511 | } |
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512 | |||
513 | /*
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514 | * Return device information.
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515 | */
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516 | int
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517 | device_info(struct devinfo *info)
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518 | { |
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519 | u_long target = info->cookie; |
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520 | u_long i = 0;
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521 | device_t dev; |
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522 | int error = ESRCH;
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523 | |||
524 | sched_lock(); |
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525 | for (dev = device_list; dev != NULL; dev = dev->next) { |
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526 | if (i++ == target) {
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527 | info->cookie = i; |
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528 | info->id = dev; |
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529 | info->flags = dev->flags; |
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530 | strlcpy(info->name, dev->name, MAXDEVNAME); |
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531 | error = 0;
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532 | break;
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533 | } |
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534 | } |
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535 | sched_unlock(); |
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536 | return error;
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537 | } |
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538 | |||
539 | /*
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540 | * Initialize device driver module.
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541 | */
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542 | void
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543 | device_init(void)
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544 | { |
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545 | struct module *mod;
|
||
546 | struct bootinfo *bi;
|
||
547 | void (*entry)(const dkifn_t *); |
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548 | |||
549 | machine_bootinfo(&bi); |
||
550 | mod = &bi->driver; |
||
551 | if (mod == NULL) { |
||
552 | DPRINTF(("Warning: No driver found\n"));
|
||
553 | return;
|
||
554 | } |
||
555 | entry = (void (*)(const dkifn_t *))mod->entry; |
||
556 | ASSERT(entry != NULL);
|
||
557 | |||
558 | /* Show module location to add the driver symbols for gdb. */
|
||
559 | DPRINTF(("Entering driver module (at 0x%x)\n", (int)entry)); |
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560 | |||
561 | (*entry)(dkient); |
||
562 | } |