Annotation of qemu/hw/parallel.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * QEMU Parallel PORT emulation
        !             3:  * 
        !             4:  * Copyright (c) 2003-2004 Fabrice Bellard
        !             5:  * 
        !             6:  * Permission is hereby granted, free of charge, to any person obtaining a copy
        !             7:  * of this software and associated documentation files (the "Software"), to deal
        !             8:  * in the Software without restriction, including without limitation the rights
        !             9:  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
        !            10:  * copies of the Software, and to permit persons to whom the Software is
        !            11:  * furnished to do so, subject to the following conditions:
        !            12:  *
        !            13:  * The above copyright notice and this permission notice shall be included in
        !            14:  * all copies or substantial portions of the Software.
        !            15:  *
        !            16:  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
        !            17:  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
        !            18:  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
        !            19:  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
        !            20:  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
        !            21:  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
        !            22:  * THE SOFTWARE.
        !            23:  */
        !            24: #include "vl.h"
        !            25: 
        !            26: //#define DEBUG_PARALLEL
        !            27: 
        !            28: /*
        !            29:  * These are the definitions for the Printer Status Register
        !            30:  */
        !            31: #define PARA_STS_BUSY  0x80    /* Busy complement */
        !            32: #define PARA_STS_ACK   0x40    /* Acknowledge */
        !            33: #define PARA_STS_PAPER 0x20    /* Out of paper */
        !            34: #define PARA_STS_ONLINE        0x10    /* Online */
        !            35: #define PARA_STS_ERROR 0x08    /* Error complement */
        !            36: 
        !            37: /*
        !            38:  * These are the definitions for the Printer Control Register
        !            39:  */
        !            40: #define PARA_CTR_INTEN 0x10    /* IRQ Enable */
        !            41: #define PARA_CTR_SELECT        0x08    /* Select In complement */
        !            42: #define PARA_CTR_INIT  0x04    /* Initialize Printer complement */
        !            43: #define PARA_CTR_AUTOLF        0x02    /* Auto linefeed complement */
        !            44: #define PARA_CTR_STROBE        0x01    /* Strobe complement */
        !            45: 
        !            46: struct ParallelState {
        !            47:     uint8_t data;
        !            48:     uint8_t status; /* read only register */
        !            49:     uint8_t control;
        !            50:     int irq;
        !            51:     int irq_pending;
        !            52:     CharDriverState *chr;
        !            53: };
        !            54: 
        !            55: static void parallel_update_irq(ParallelState *s)
        !            56: {
        !            57:     if (s->irq_pending)
        !            58:         pic_set_irq(s->irq, 1);
        !            59:     else
        !            60:         pic_set_irq(s->irq, 0);
        !            61: }
        !            62: 
        !            63: static void parallel_ioport_write(void *opaque, uint32_t addr, uint32_t val)
        !            64: {
        !            65:     ParallelState *s = opaque;
        !            66:     
        !            67:     addr &= 7;
        !            68: #ifdef DEBUG_PARALLEL
        !            69:     printf("parallel: write addr=0x%02x val=0x%02x\n", addr, val);
        !            70: #endif
        !            71:     switch(addr) {
        !            72:     case 0:
        !            73:         s->data = val;
        !            74:         parallel_update_irq(s);
        !            75:         break;
        !            76:     case 2:
        !            77:         if ((val & PARA_CTR_INIT) == 0 ) {
        !            78:             s->status = PARA_STS_BUSY;
        !            79:             s->status |= PARA_STS_ACK;
        !            80:             s->status |= PARA_STS_ONLINE;
        !            81:             s->status |= PARA_STS_ERROR;
        !            82:         }
        !            83:         else if (val & PARA_CTR_SELECT) {
        !            84:             if (val & PARA_CTR_STROBE) {
        !            85:                 s->status &= ~PARA_STS_BUSY;
        !            86:                 if ((s->control & PARA_CTR_STROBE) == 0)
        !            87:                     qemu_chr_write(s->chr, &s->data, 1);
        !            88:             } else {
        !            89:                 if (s->control & PARA_CTR_INTEN) {
        !            90:                     s->irq_pending = 1;
        !            91:                 }
        !            92:             }
        !            93:         }
        !            94:         parallel_update_irq(s);
        !            95:         s->control = val;
        !            96:         break;
        !            97:     }
        !            98: }
        !            99: 
        !           100: static uint32_t parallel_ioport_read(void *opaque, uint32_t addr)
        !           101: {
        !           102:     ParallelState *s = opaque;
        !           103:     uint32_t ret = 0xff;
        !           104: 
        !           105:     addr &= 7;
        !           106:     switch(addr) {
        !           107:     case 0:
        !           108:         ret = s->data; 
        !           109:         break;
        !           110:     case 1:
        !           111:         ret = s->status;
        !           112:         s->irq_pending = 0;
        !           113:         if ((s->status & PARA_STS_BUSY) == 0 && (s->control & PARA_CTR_STROBE) == 0) {
        !           114:             /* XXX Fixme: wait 5 microseconds */
        !           115:             if (s->status & PARA_STS_ACK)
        !           116:                 s->status &= ~PARA_STS_ACK;
        !           117:             else {
        !           118:             /* XXX Fixme: wait 5 microseconds */
        !           119:                 s->status |= PARA_STS_ACK;
        !           120:                 s->status |= PARA_STS_BUSY;
        !           121:             }
        !           122:         }
        !           123:         parallel_update_irq(s);
        !           124:         break;
        !           125:     case 2:
        !           126:         ret = s->control;
        !           127:         break;
        !           128:     }
        !           129: #ifdef DEBUG_PARALLEL
        !           130:     printf("parallel: read addr=0x%02x val=0x%02x\n", addr, ret);
        !           131: #endif
        !           132:     return ret;
        !           133: }
        !           134: 
        !           135: static int parallel_can_receive(ParallelState *s)
        !           136: {
        !           137:     return 0;
        !           138: }
        !           139: 
        !           140: static void parallel_receive_byte(ParallelState *s, int ch)
        !           141: {
        !           142: }
        !           143: 
        !           144: static int parallel_can_receive1(void *opaque)
        !           145: {
        !           146:     ParallelState *s = opaque;
        !           147:     return parallel_can_receive(s);
        !           148: }
        !           149: 
        !           150: static void parallel_receive1(void *opaque, const uint8_t *buf, int size)
        !           151: {
        !           152:     ParallelState *s = opaque;
        !           153:     parallel_receive_byte(s, buf[0]);
        !           154: }
        !           155: 
        !           156: static void parallel_event(void *opaque, int event)
        !           157: {
        !           158: }
        !           159: 
        !           160: /* If fd is zero, it means that the parallel device uses the console */
        !           161: ParallelState *parallel_init(int base, int irq, CharDriverState *chr)
        !           162: {
        !           163:     ParallelState *s;
        !           164: 
        !           165:     s = qemu_mallocz(sizeof(ParallelState));
        !           166:     if (!s)
        !           167:         return NULL;
        !           168:     s->irq = irq;
        !           169:     s->data = 0;
        !           170:     s->status = PARA_STS_BUSY;
        !           171:     s->status |= PARA_STS_ACK;
        !           172:     s->status |= PARA_STS_ONLINE;
        !           173:     s->status |= PARA_STS_ERROR;
        !           174:     s->control = PARA_CTR_SELECT;
        !           175:     s->control |= PARA_CTR_INIT;
        !           176: 
        !           177:     register_ioport_write(base, 8, 1, parallel_ioport_write, s);
        !           178:     register_ioport_read(base, 8, 1, parallel_ioport_read, s);
        !           179:     s->chr = chr;
        !           180:     qemu_chr_add_read_handler(chr, parallel_can_receive1, parallel_receive1, s);
        !           181:     qemu_chr_add_event_handler(chr, parallel_event);
        !           182:     return s;
        !           183: }

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