1 | /* |
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2 | * This file contains the implementation of the function described in irq.h |
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3 | * related to Intel 8259 Programmable Interrupt controller. |
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4 | * |
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5 | * Copyright (C) 1998, 1999 valette@crf.canon.fr |
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6 | * |
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7 | * The license and distribution terms for this file may be |
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8 | * found in the file LICENSE in this distribution or at |
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9 | * http://www.rtems.org/license/LICENSE. |
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10 | */ |
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11 | |
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12 | #include <bsp.h> |
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13 | #include <bsp/irq.h> |
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14 | |
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15 | /*-------------------------------------------------------------------------+ |
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16 | | Cache for 1st and 2nd PIC IRQ line's status (enabled or disabled) register. |
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17 | +--------------------------------------------------------------------------*/ |
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18 | /* |
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19 | * lower byte is interrupt mask on the master PIC. |
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20 | * while upper bits are interrupt on the slave PIC. |
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21 | */ |
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22 | volatile rtems_i8259_masks i8259s_cache = 0xfffb; |
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23 | |
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24 | /*-------------------------------------------------------------------------+ |
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25 | | Function: BSP_irq_disable_at_i8259s |
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26 | | Description: Mask IRQ line in appropriate PIC chip. |
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27 | | Global Variables: i8259s_cache |
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28 | | Arguments: vector_offset - number of IRQ line to mask. |
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29 | | Returns: original state or -1 on error. |
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30 | +--------------------------------------------------------------------------*/ |
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31 | int BSP_irq_disable_at_i8259s (const rtems_irq_number irqLine) |
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32 | { |
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33 | unsigned short mask; |
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34 | rtems_interrupt_level level; |
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35 | int rval; |
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36 | |
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37 | if ( ((int)irqLine < BSP_ISA_IRQ_LOWEST_OFFSET) || |
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38 | ((int)irqLine > BSP_ISA_IRQ_MAX_OFFSET) |
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39 | ) |
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40 | return -1; |
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41 | |
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42 | rtems_interrupt_disable(level); |
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43 | |
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44 | mask = 1 << irqLine; |
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45 | rval = i8259s_cache & mask ? 0 : 1; |
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46 | i8259s_cache |= mask; |
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47 | |
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48 | if (irqLine < 8) |
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49 | { |
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50 | outport_byte(PIC_MASTER_IMR_IO_PORT, i8259s_cache & 0xff); |
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51 | } |
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52 | else |
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53 | { |
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54 | outport_byte(PIC_SLAVE_IMR_IO_PORT, ((i8259s_cache & 0xff00) >> 8)); |
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55 | } |
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56 | rtems_interrupt_enable(level); |
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57 | |
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58 | return rval; |
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59 | } |
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60 | |
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61 | /*-------------------------------------------------------------------------+ |
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62 | | Function: BSP_irq_enable_at_i8259s |
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63 | | Description: Unmask IRQ line in appropriate PIC chip. |
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64 | | Global Variables: i8259s_cache |
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65 | | Arguments: irqLine - number of IRQ line to mask. |
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66 | | Returns: Nothing. |
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67 | +--------------------------------------------------------------------------*/ |
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68 | int BSP_irq_enable_at_i8259s (const rtems_irq_number irqLine) |
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69 | { |
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70 | unsigned short mask; |
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71 | rtems_interrupt_level level; |
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72 | |
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73 | if ( ((int)irqLine < BSP_ISA_IRQ_LOWEST_OFFSET) || |
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74 | ((int)irqLine > BSP_ISA_IRQ_MAX_OFFSET ) |
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75 | ) |
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76 | return 1; |
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77 | |
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78 | rtems_interrupt_disable(level); |
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79 | |
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80 | mask = ~(1 << irqLine); |
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81 | i8259s_cache &= mask; |
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82 | |
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83 | if (irqLine < 8) |
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84 | { |
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85 | outport_byte(PIC_MASTER_IMR_IO_PORT, i8259s_cache & 0xff); |
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86 | } |
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87 | else |
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88 | { |
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89 | outport_byte(PIC_SLAVE_IMR_IO_PORT, ((i8259s_cache & 0xff00) >> 8)); |
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90 | } |
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91 | rtems_interrupt_enable(level); |
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92 | |
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93 | return 0; |
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94 | } /* mask_irq */ |
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95 | |
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96 | int BSP_irq_enabled_at_i8259s (const rtems_irq_number irqLine) |
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97 | { |
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98 | unsigned short mask; |
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99 | |
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100 | if ( ((int)irqLine < BSP_ISA_IRQ_LOWEST_OFFSET) || |
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101 | ((int)irqLine > BSP_ISA_IRQ_MAX_OFFSET) |
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102 | ) |
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103 | return 1; |
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104 | |
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105 | mask = (1 << irqLine); |
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106 | return (~(i8259s_cache & mask)); |
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107 | } |
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108 | |
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109 | /*-------------------------------------------------------------------------+ |
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110 | | Function: BSP_irq_ack_at_i8259s |
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111 | | Description: Signal generic End Of Interrupt (EOI) to appropriate PIC. |
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112 | | Global Variables: None. |
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113 | | Arguments: irqLine - number of IRQ line to acknowledge. |
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114 | | Returns: Nothing. |
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115 | +--------------------------------------------------------------------------*/ |
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116 | int BSP_irq_ack_at_i8259s (const rtems_irq_number irqLine) |
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117 | { |
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118 | if (irqLine >= 8) { |
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119 | outport_byte(PIC_MASTER_COMMAND_IO_PORT, SLAVE_PIC_EOSI); |
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120 | outport_byte(PIC_SLAVE_COMMAND_IO_PORT, (PIC_EOSI | (irqLine - 8))); |
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121 | } |
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122 | else { |
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123 | outport_byte(PIC_MASTER_COMMAND_IO_PORT, (PIC_EOSI | irqLine)); |
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124 | } |
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125 | |
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126 | return 0; |
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127 | |
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128 | } /* ackIRQ */ |
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129 | |
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130 | void BSP_i8259s_init(void) |
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131 | { |
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132 | /* |
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133 | * init master 8259 interrupt controller |
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134 | */ |
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135 | outport_byte(PIC_MASTER_COMMAND_IO_PORT, 0x11); /* Start init sequence */ |
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136 | outport_byte(PIC_MASTER_IMR_IO_PORT, 0x00);/* Vector base = 0 */ |
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137 | outport_byte(PIC_MASTER_IMR_IO_PORT, 0x04);/* edge tiggered, Cascade (slave) on IRQ2 */ |
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138 | outport_byte(PIC_MASTER_IMR_IO_PORT, 0x01);/* Select 8086 mode */ |
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139 | outport_byte(PIC_MASTER_IMR_IO_PORT, 0xFB); /* Mask all except cascade */ |
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140 | /* |
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141 | * init slave interrupt controller |
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142 | */ |
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143 | outport_byte(PIC_SLAVE_COMMAND_IO_PORT, 0x11); /* Start init sequence */ |
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144 | outport_byte(PIC_SLAVE_IMR_IO_PORT, 0x08);/* Vector base = 8 */ |
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145 | outport_byte(PIC_SLAVE_IMR_IO_PORT, 0x02);/* edge triggered, Cascade (slave) on IRQ2 */ |
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146 | outport_byte(PIC_SLAVE_IMR_IO_PORT, 0x01); /* Select 8086 mode */ |
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147 | outport_byte(PIC_SLAVE_IMR_IO_PORT, 0xFF); /* Mask all */ |
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148 | |
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149 | } |
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