1 | /* UART driver for Blackfin |
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2 | * |
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3 | * Copyright (c) 2008 Kallisti Labs, Los Gatos, CA, USA |
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4 | * written by Allan Hessenflow <allanh@kallisti.com> |
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5 | * |
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6 | * The license and distribution terms for this file may be |
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7 | * found in the file LICENSE in this distribution or at |
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8 | * http://www.rtems.com/license/LICENSE. |
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9 | * |
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10 | * $Id$ |
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11 | */ |
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12 | |
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13 | |
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14 | #include <rtems.h> |
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15 | #include <rtems/libio.h> |
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16 | #include <rtems/termiostypes.h> |
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17 | #include <termios.h> |
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18 | #include <stdlib.h> |
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19 | |
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20 | #include <libcpu/uartRegs.h> |
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21 | #include "uart.h" |
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22 | |
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23 | |
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24 | /* flags */ |
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25 | #define BFIN_UART_XMIT_BUSY 0x01 |
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26 | |
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27 | |
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28 | static bfin_uart_config_t *uartsConfig; |
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29 | |
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30 | |
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31 | static void initializeHardware(int minor) { |
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32 | uint16_t divisor; |
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33 | char *base; |
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34 | uint16_t r; |
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35 | |
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36 | base = uartsConfig->channels[minor].base_address; |
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37 | |
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38 | *(uint16_t volatile *) (base + UART_IER_OFFSET) = 0; |
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39 | |
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40 | if (uartsConfig->channels[minor].force_baud) |
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41 | divisor = (uint16_t) (uartsConfig->freq / |
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42 | (uartsConfig->channels[minor].force_baud * 16)); |
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43 | else |
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44 | divisor = (uint16_t) (uartsConfig->freq / (9600 * 16)); |
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45 | *(uint16_t volatile *) (base + UART_LCR_OFFSET) = UART_LCR_DLAB; |
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46 | *(uint16_t volatile *) (base + UART_DLL_OFFSET) = (divisor & 0xff); |
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47 | *(uint16_t volatile *) (base + UART_DLH_OFFSET) = ((divisor >> 8) & 0xff); |
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48 | |
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49 | *(uint16_t volatile *) (base + UART_LCR_OFFSET) = UART_LCR_WLS_8; |
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50 | |
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51 | *(uint16_t volatile *) (base + UART_GCTL_OFFSET) = UART_GCTL_UCEN; |
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52 | |
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53 | r = *(uint16_t volatile *) (base + UART_LSR_OFFSET); |
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54 | r = *(uint16_t volatile *) (base + UART_RBR_OFFSET); |
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55 | r = *(uint16_t volatile *) (base + UART_IIR_OFFSET); |
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56 | |
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57 | return; |
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58 | } |
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59 | |
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60 | static int pollRead(int minor) { |
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61 | int c; |
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62 | char *base; |
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63 | |
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64 | base = uartsConfig->channels[minor].base_address; |
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65 | |
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66 | /* check to see if driver is using interrupts so this call will be |
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67 | harmless (though non-functional) in case some debug code tries to |
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68 | use it */ |
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69 | if (!uartsConfig->channels[minor].use_interrupts && |
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70 | *((uint16_t volatile *) (base + UART_LSR_OFFSET)) & UART_LSR_DR) |
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71 | c = *((uint16_t volatile *) (base + UART_RBR_OFFSET)); |
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72 | else |
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73 | c = -1; |
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74 | |
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75 | return c; |
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76 | } |
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77 | |
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78 | char bfin_uart_poll_read(int minor) { |
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79 | int c; |
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80 | |
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81 | do { |
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82 | c = pollRead(minor); |
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83 | } while (c == -1); |
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84 | |
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85 | return c; |
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86 | } |
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87 | |
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88 | void bfin_uart_poll_write(int minor, char c) { |
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89 | char *base; |
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90 | |
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91 | base = uartsConfig->channels[minor].base_address; |
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92 | |
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93 | while (!(*((uint16_t volatile *) (base + UART_LSR_OFFSET)) & UART_LSR_THRE)) |
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94 | ; |
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95 | *(uint16_t volatile *) (base + UART_THR_OFFSET) = c; |
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96 | } |
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97 | |
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98 | /* begin BISON */ |
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99 | void debug_write_char(char c) { |
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100 | bfin_uart_poll_write(0, c); |
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101 | } |
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102 | |
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103 | void debug_write_string(char *s) { |
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104 | |
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105 | while (s && *s) { |
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106 | if (*s == '\n') |
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107 | debug_write_char('\r'); |
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108 | debug_write_char(*s++); |
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109 | } |
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110 | } |
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111 | |
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112 | void debug_write_crlf(void) { |
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113 | |
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114 | debug_write_char('\r'); |
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115 | debug_write_char('\n'); |
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116 | } |
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117 | |
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118 | void debug_write_nybble(int nybble) { |
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119 | |
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120 | nybble &= 0x0f; |
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121 | debug_write_char((nybble > 9) ? 'a' + (nybble - 10) : '0' + nybble); |
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122 | } |
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123 | |
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124 | void debug_write_byte(int byte) { |
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125 | |
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126 | byte &= 0xff; |
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127 | debug_write_nybble(byte >> 4); |
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128 | debug_write_nybble(byte & 0x0f); |
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129 | } |
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130 | |
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131 | void debug_write_half(int half) { |
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132 | |
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133 | half &= 0xffff; |
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134 | debug_write_byte(half >> 8); |
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135 | debug_write_byte(half & 0xff); |
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136 | } |
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137 | |
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138 | void debug_write_word(int word) { |
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139 | |
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140 | word &= 0xffffffff; |
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141 | debug_write_half(word >> 16); |
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142 | debug_write_half(word & 0xffff); |
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143 | } |
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144 | /* end BISON */ |
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145 | |
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146 | /* |
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147 | * Console Termios Support Entry Points |
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148 | * |
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149 | */ |
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150 | |
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151 | static ssize_t pollWrite(int minor, const char *buf, size_t len) { |
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152 | |
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153 | size_t count; |
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154 | for ( count = 0; count < len; count++ ) |
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155 | bfin_uart_poll_write(minor, *buf++); |
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156 | |
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157 | return count; |
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158 | } |
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159 | |
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160 | static void enableInterrupts(int minor) { |
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161 | char *base; |
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162 | |
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163 | base = uartsConfig->channels[minor].base_address; |
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164 | |
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165 | *(uint16_t volatile *) (base + UART_IER_OFFSET) = UART_IER_ETBEI | |
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166 | UART_IER_ERBFI; |
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167 | } |
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168 | |
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169 | static void disableAllInterrupts(void) { |
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170 | int i; |
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171 | char *base; |
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172 | |
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173 | for (i = 0; i < uartsConfig->num_channels; i++) { |
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174 | base = uartsConfig->channels[i].base_address; |
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175 | *(uint16_t volatile *) (base + UART_IER_OFFSET) = 0; |
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176 | } |
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177 | } |
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178 | |
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179 | static ssize_t interruptWrite(int minor, const char *buf, size_t len) { |
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180 | char *base; |
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181 | |
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182 | base = uartsConfig->channels[minor].base_address; |
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183 | |
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184 | uartsConfig->channels[minor].flags |= BFIN_UART_XMIT_BUSY; |
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185 | *(uint16_t volatile *) (base + UART_THR_OFFSET) = *buf; |
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186 | |
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187 | /* one byte written */ |
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188 | return 1; |
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189 | } |
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190 | |
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191 | static int setAttributes(int minor, const struct termios *termios) { |
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192 | char *base; |
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193 | int baud; |
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194 | uint16_t divisor; |
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195 | uint16_t lcr; |
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196 | |
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197 | base = uartsConfig->channels[minor].base_address; |
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198 | switch (termios->c_cflag & CBAUD) { |
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199 | case B0: |
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200 | baud = 0; |
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201 | break; |
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202 | case B50: |
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203 | baud = 50; |
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204 | break; |
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205 | case B75: |
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206 | baud = 75; |
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207 | break; |
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208 | case B110: |
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209 | baud = 110; |
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210 | break; |
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211 | case B134: |
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212 | baud = 134; |
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213 | break; |
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214 | case B150: |
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215 | baud = 150; |
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216 | break; |
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217 | case B200: |
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218 | baud = 200; |
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219 | break; |
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220 | case B300: |
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221 | baud = 300; |
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222 | break; |
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223 | case B600: |
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224 | baud = 600; |
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225 | break; |
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226 | case B1200: |
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227 | baud = 1200; |
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228 | break; |
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229 | case B1800: |
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230 | baud = 1800; |
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231 | break; |
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232 | case B2400: |
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233 | baud = 2400; |
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234 | break; |
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235 | case B4800: |
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236 | baud = 4800; |
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237 | break; |
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238 | case B9600: |
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239 | baud = 9600; |
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240 | break; |
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241 | case B19200: |
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242 | baud = 19200; |
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243 | break; |
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244 | case B38400: |
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245 | baud = 38400; |
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246 | break; |
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247 | case B57600: |
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248 | baud = 57600; |
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249 | break; |
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250 | case B115200: |
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251 | baud = 115200; |
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252 | break; |
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253 | case B230400: |
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254 | baud = 230400; |
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255 | break; |
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256 | case B460800: |
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257 | baud = 460800; |
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258 | break; |
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259 | default: |
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260 | baud = -1; |
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261 | break; |
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262 | } |
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263 | if (baud > 0 && uartsConfig->channels[minor].force_baud) |
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264 | baud = uartsConfig->channels[minor].force_baud; |
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265 | switch (termios->c_cflag & CSIZE) { |
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266 | case CS5: |
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267 | lcr = UART_LCR_WLS_5; |
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268 | break; |
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269 | case CS6: |
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270 | lcr = UART_LCR_WLS_6; |
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271 | break; |
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272 | case CS7: |
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273 | lcr = UART_LCR_WLS_7; |
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274 | break; |
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275 | case CS8: |
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276 | default: |
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277 | lcr = UART_LCR_WLS_8; |
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278 | break; |
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279 | } |
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280 | switch (termios->c_cflag & (PARENB | PARODD)) { |
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281 | case PARENB: |
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282 | lcr |= UART_LCR_PEN | UART_LCR_EPS; |
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283 | break; |
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284 | case PARENB | PARODD: |
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285 | lcr |= UART_LCR_PEN; |
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286 | break; |
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287 | default: |
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288 | break; |
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289 | } |
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290 | if (termios->c_cflag & CSTOPB) |
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291 | lcr |= UART_LCR_STB; |
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292 | |
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293 | if (baud > 0) { |
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294 | divisor = (uint16_t) (uartsConfig->freq / (baud * 16)); |
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295 | *(uint16_t volatile *) (base + UART_LCR_OFFSET) = lcr | UART_LCR_DLAB; |
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296 | *(uint16_t volatile *) (base + UART_DLL_OFFSET) = (divisor & 0xff); |
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297 | *(uint16_t volatile *) (base + UART_DLH_OFFSET) = ((divisor >> 8) & 0xff); |
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298 | } |
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299 | *(uint16_t volatile *) (base + UART_LCR_OFFSET) = lcr; |
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300 | |
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301 | return 0; |
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302 | } |
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303 | |
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304 | void bfin_uart_isr(int source) { |
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305 | int i; |
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306 | char *base; |
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307 | uint16_t uartStat; |
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308 | char c; |
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309 | uint8_t uartLSR; |
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310 | |
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311 | /* Just use one ISR and check for all UART interrupt sources in it. |
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312 | This is less efficient than making use of the vector to narrow down |
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313 | the things we need to check, but not all Blackfins separate the |
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314 | UART interrupt sources in the same ways. This way we don't have |
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315 | to make this code dependent on the type of Blackfin. */ |
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316 | for (i = 0; i < uartsConfig->num_channels; i++) { |
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317 | if (uartsConfig->channels[i].use_interrupts) { |
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318 | base = uartsConfig->channels[i].base_address; |
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319 | uartStat = *(uint16_t volatile *) (base + UART_IIR_OFFSET); |
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320 | if ((uartStat & UART_IIR_NINT) == 0) { |
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321 | switch (uartStat & UART_IIR_STATUS_MASK) { |
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322 | case UART_IIR_STATUS_THRE: |
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323 | if (uartsConfig->channels[i].termios && |
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324 | (uartsConfig->channels[i].flags & BFIN_UART_XMIT_BUSY)) { |
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325 | uartsConfig->channels[i].flags &= ~BFIN_UART_XMIT_BUSY; |
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326 | rtems_termios_dequeue_characters(uartsConfig->channels[i].termios, |
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327 | 1); |
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328 | } |
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329 | break; |
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330 | case UART_IIR_STATUS_RDR: |
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331 | c = *(uint16_t volatile *) (base + UART_RBR_OFFSET); |
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332 | if (uartsConfig->channels[i].termios) |
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333 | rtems_termios_enqueue_raw_characters( |
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334 | uartsConfig->channels[i].termios, &c, 1); |
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335 | break; |
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336 | case UART_IIR_STATUS_LS: |
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337 | uartLSR = *(uint16_t volatile *) (base + UART_LSR_OFFSET); |
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338 | /* break, framing error, parity error, or overrun error |
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339 | has been detected */ |
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340 | break; |
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341 | default: |
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342 | break; |
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343 | } |
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344 | } |
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345 | } |
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346 | } |
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347 | } |
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348 | |
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349 | rtems_status_code bfin_uart_initialize(rtems_device_major_number major, |
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350 | bfin_uart_config_t *config) { |
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351 | rtems_status_code status; |
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352 | int i; |
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353 | |
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354 | status = RTEMS_SUCCESSFUL; |
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355 | |
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356 | rtems_termios_initialize(); |
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357 | |
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358 | /* |
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359 | * Register Device Names |
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360 | */ |
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361 | |
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362 | uartsConfig = config; |
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363 | for (i = 0; i < config->num_channels; i++) { |
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364 | config->channels[i].termios = NULL; |
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365 | config->channels[i].flags = 0; |
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366 | initializeHardware(i); |
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367 | status = rtems_io_register_name(config->channels[i].name, major, i); |
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368 | } |
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369 | |
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370 | return RTEMS_SUCCESSFUL; |
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371 | } |
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372 | |
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373 | rtems_device_driver bfin_uart_open(rtems_device_major_number major, |
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374 | rtems_device_minor_number minor, |
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375 | void *arg) { |
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376 | rtems_status_code sc; |
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377 | rtems_libio_open_close_args_t *args; |
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378 | static const rtems_termios_callbacks pollCallbacks = { |
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379 | NULL, /* firstOpen */ |
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380 | NULL, /* lastClose */ |
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381 | pollRead, /* pollRead */ |
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382 | pollWrite, /* write */ |
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383 | setAttributes, /* setAttributes */ |
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384 | NULL, /* stopRemoteTx */ |
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385 | NULL, /* startRemoteTx */ |
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386 | TERMIOS_POLLED /* outputUsesInterrupts */ |
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387 | }; |
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388 | static const rtems_termios_callbacks interruptCallbacks = { |
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389 | NULL, /* firstOpen */ |
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390 | NULL, /* lastClose */ |
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391 | NULL, /* pollRead */ |
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392 | interruptWrite, /* write */ |
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393 | setAttributes, /* setAttributes */ |
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394 | NULL, /* stopRemoteTx */ |
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395 | NULL, /* startRemoteTx */ |
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396 | TERMIOS_IRQ_DRIVEN /* outputUsesInterrupts */ |
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397 | }; |
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398 | |
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399 | if (uartsConfig == NULL || minor < 0 || minor >= uartsConfig->num_channels) |
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400 | return RTEMS_INVALID_NUMBER; |
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401 | |
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402 | sc = rtems_termios_open(major, minor, arg, |
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403 | uartsConfig->channels[minor].use_interrupts ? |
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404 | &interruptCallbacks : &pollCallbacks); |
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405 | args = arg; |
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406 | uartsConfig->channels[minor].termios = args->iop->data1; |
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407 | |
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408 | if (uartsConfig->channels[minor].use_interrupts) |
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409 | enableInterrupts(minor); |
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410 | atexit(disableAllInterrupts); |
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411 | |
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412 | return sc; |
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413 | } |
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414 | |
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