core/serirq.c

   1 /*
   2  * -----------------------------------------------------------------------
   3  *
   4  *   Copyright 2009 Intel Corporation; author: H. Peter Anvin
   5  *
   6  *   This program is free software; you can redistribute it and/or modify
   7  *   it under the terms of the GNU General Public License as published by
   8  *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
   9  *   Boston MA 02111-1307, USA; either version 2 of the License, or
  10  *   (at your option) any later version; incorporated herein by reference.
  11  *
  12  * -----------------------------------------------------------------------
  13  *
  14  * serirq.c
  15  *
  16  * Serial port IRQ code
  17  *
  18  * We don't know what IRQ, if any, we have, so map all of them...
  19  */
  20 #include <sys/io.h>
  21 #include <string.h>
  22
  23 #include <fs.h>
  24 #include "bios.h"
  25
  26 static char serial_buf[serial_buf_size];
  27
  28 static unsigned short SerialIRQPort; /* Serial port w IRQ service */
  29 char *SerialHead = serial_buf;    /* Head of serial port rx buffer */
  30 char *SerialTail = serial_buf;    /* Tail of serial port rx buffer */
  31
  32 static unsigned char IRQMask[2];             /* PIC IRQ mask status */
  33
  34 static unsigned int oldirq[16];
  35
  36 typedef void (*irqhandler_t)(void);
  37
  38 void sirq_cleanup(void);
  39
  40 static void irq_common(unsigned short old_irq)
  41 {
  42         char *dst;
  43         irqhandler_t next;
  44         char val;
  45
  46         dst = SerialHead;
  47         next = (irqhandler_t)oldirq[old_irq];
  48
  49         /* LSR */
  50         val = inb(SerialPort + 5);
  51
  52         /* Received data */
  53         while (val & 1) {
  54                 /* RDR */
  55                 *dst++ = inb(SerialPort);
  56                 /* LSR */
  57                 val = inb(SerialPort + 5);
  58                 if ((val & FlowIgnore) == FlowIgnore) {
  59                         /* Wrap around if necessary */
  60                         dst = (char *)((unsigned long)dst & (serial_buf_size - 1));
  61
  62                         /* Would this cause overflow? */
  63                         if (dst != SerialTail)
  64                                 SerialHead = dst;
  65                 }
  66         }
  67
  68         /* Chain to next handler */
  69         next();
  70 }
  71
  72 #define SERIAL_IRQ_HANDLER(n) \
  73         static void serstub_irq##n(void)        \
  74         {                                       \
  75                 irq_common(n);                  \
  76         }
  77
  78 SERIAL_IRQ_HANDLER(0);
  79 SERIAL_IRQ_HANDLER(1);
  80 SERIAL_IRQ_HANDLER(2);
  81 SERIAL_IRQ_HANDLER(3);
  82 SERIAL_IRQ_HANDLER(4);
  83 SERIAL_IRQ_HANDLER(5);
  84 SERIAL_IRQ_HANDLER(6);
  85 SERIAL_IRQ_HANDLER(7);
  86 SERIAL_IRQ_HANDLER(8);
  87 SERIAL_IRQ_HANDLER(9);
  88 SERIAL_IRQ_HANDLER(10);
  89 SERIAL_IRQ_HANDLER(11);
  90 SERIAL_IRQ_HANDLER(12);
  91 SERIAL_IRQ_HANDLER(13);
  92 SERIAL_IRQ_HANDLER(14);
  93 SERIAL_IRQ_HANDLER(15);
  94
  95 static inline void save_irq_vectors(uint32_t *src, uint32_t *dst)
  96 {
  97         int i;
  98
  99         for (i = 0; i < 8; i++)
 100                 *dst++ = *src++;
 101 }
 102
 103 static inline void install_irq_vectors(uint32_t *dst, int first)
 104 {
 105         if (first) {
 106                 *dst++ = (uint32_t)serstub_irq0;
 107                 *dst++ = (uint32_t)serstub_irq1;
 108                 *dst++ = (uint32_t)serstub_irq2;
 109                 *dst++ = (uint32_t)serstub_irq3;
 110                 *dst++ = (uint32_t)serstub_irq4;
 111                 *dst++ = (uint32_t)serstub_irq5;
 112                 *dst++ = (uint32_t)serstub_irq6;
 113                 *dst++ = (uint32_t)serstub_irq7;
 114         } else {
 115                 *dst++ = (uint32_t)serstub_irq8;
 116                 *dst++ = (uint32_t)serstub_irq9;
 117                 *dst++ = (uint32_t)serstub_irq10;
 118                 *dst++ = (uint32_t)serstub_irq11;
 119                 *dst++ = (uint32_t)serstub_irq12;
 120                 *dst++ = (uint32_t)serstub_irq13;
 121                 *dst++ = (uint32_t)serstub_irq14;
 122                 *dst++ = (uint32_t)serstub_irq15;
 123         }
 124 }
 125
 126 __export void sirq_install(void)
 127 {
 128         char val, val2;
 129
 130         sirq_cleanup();
 131
 132         save_irq_vectors((uint32_t *)(4 * 0x8), oldirq);
 133         save_irq_vectors((uint32_t *)(4 * 0x70), &oldirq[8]);
 134
 135         install_irq_vectors((uint32_t *)(4 * 0x8), 1);
 136         install_irq_vectors((uint32_t *)(4 * 0x70), 0);
 137
 138         SerialIRQPort = SerialPort;
 139
 140         /* Clear DLAB (should already be...) */
 141         outb(0x3, SerialIRQPort + 5);
 142         io_delay();
 143
 144         /* Enable receive interrupt */
 145         outb(0x1, SerialIRQPort + 1);
 146         io_delay();
 147
 148         /*
 149          * Enable all the interrupt lines at the PIC. Some BIOSes only
 150          * enable the timer interrupts and other interrupts actively
 151          * in use by the BIOS.
 152          */
 153
 154         /* Secondary PIC mask register */
 155         val = inb(0xA1);
 156         val2 = inb(0x21);
 157         IRQMask[0] = val;
 158         IRQMask[1] = val2;
 159
 160         io_delay();
 161
 162         /* Remove all interrupt masks */
 163         outb(0x21, 0);
 164         outb(0xA1, 0);
 165 }
 166
 167 __export void sirq_cleanup_nowipe(void)
 168 {
 169         uint32_t *dst;
 170         int i;
 171
 172         if (!SerialIRQPort)
 173                 return;
 174
 175         /* Clear DLAB */
 176         outb(0x3, SerialIRQPort + 5);
 177         io_delay();
 178
 179         /* Clear IER */
 180         outb(0x0, SerialIRQPort + 1);
 181         io_delay();
 182
 183         /* Restore PIC masks */
 184         outb(IRQMask[0], 0x21);
 185         outb(IRQMask[1], 0xA1);
 186
 187         /* Restore the original interrupt vectors */
 188         dst = (uint32_t *)(4 * 0x8);
 189         for (i = 0; i < 8; i++)
 190                 *dst++ = oldirq[i];
 191
 192         dst = (uint32_t *)(4 * 0x70);
 193         for (i = 8; i < 16; i++)
 194                 *dst++ = oldirq[i];
 195
 196         /* No active interrupt system */
 197         SerialIRQPort = 0;
 198 }
 199
 200 void sirq_cleanup(void)
 201 {
 202         sirq_cleanup_nowipe();
 203         memset(SerialHead, 0x0, serial_buf_size);
 204 }