hw/parallel.c - qemu - Git at Google

 /*
  * QEMU Parallel PORT emulation
  *
  * Copyright (c) 2003-2005 Fabrice Bellard
  * Copyright (c) 2007 Marko Kohtala
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  * copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  */
 #include "hw.h"
 #include "char/char.h"
 #include "isa.h"
 #include "pc.h"
 #include "sysemu/sysemu.h"

 //#define DEBUG_PARALLEL

 #ifdef DEBUG_PARALLEL
 #define pdebug(fmt, ...) printf("pp: " fmt, ## __VA_ARGS__)
 #else
 #define pdebug(fmt, ...) ((void)0)
 #endif

 #define PARA_REG_DATA 0
 #define PARA_REG_STS 1
 #define PARA_REG_CTR 2
 #define PARA_REG_EPP_ADDR 3
 #define PARA_REG_EPP_DATA 4

 /*
  * These are the definitions for the Printer Status Register
  */
 #define PARA_STS_BUSY	0x80	/* Busy complement */
 #define PARA_STS_ACK	0x40	/* Acknowledge */
 #define PARA_STS_PAPER	0x20	/* Out of paper */
 #define PARA_STS_ONLINE	0x10	/* Online */
 #define PARA_STS_ERROR	0x08	/* Error complement */
 #define PARA_STS_TMOUT	0x01	/* EPP timeout */

 /*
  * These are the definitions for the Printer Control Register
  */
 #define PARA_CTR_DIR	0x20	/* Direction (1=read, 0=write) */
 #define PARA_CTR_INTEN	0x10	/* IRQ Enable */
 #define PARA_CTR_SELECT	0x08	/* Select In complement */
 #define PARA_CTR_INIT	0x04	/* Initialize Printer complement */
 #define PARA_CTR_AUTOLF	0x02	/* Auto linefeed complement */
 #define PARA_CTR_STROBE	0x01	/* Strobe complement */

 #define PARA_CTR_SIGNAL (PARA_CTR_SELECT|PARA_CTR_INIT|PARA_CTR_AUTOLF|PARA_CTR_STROBE)

 typedef struct ParallelState {
     MemoryRegion iomem;
     uint8_t dataw;
     uint8_t datar;
     uint8_t status;
     uint8_t control;
     qemu_irq irq;
     int irq_pending;
     CharDriverState *chr;
     int hw_driver;
     int epp_timeout;
     uint32_t last_read_offset; /* For debugging */
     /* Memory-mapped interface */
     int it_shift;
 } ParallelState;

 typedef struct ISAParallelState {
     ISADevice dev;
     uint32_t index;
     uint32_t iobase;
     uint32_t isairq;
     ParallelState state;
 } ISAParallelState;

 static void parallel_update_irq(ParallelState *s)
 {
     if (s->irq_pending)
         qemu_irq_raise(s->irq);
     else
         qemu_irq_lower(s->irq);
 }

 static void
 parallel_ioport_write_sw(void *opaque, uint32_t addr, uint32_t val)
 {
     ParallelState *s = opaque;

     pdebug("write addr=0x%02x val=0x%02x\n", addr, val);

     addr &= 7;
     switch(addr) {
     case PARA_REG_DATA:
         s->dataw = val;
         parallel_update_irq(s);
         break;
     case PARA_REG_CTR:
         val |= 0xc0;
         if ((val & PARA_CTR_INIT) == 0 ) {
             s->status = PARA_STS_BUSY;
             s->status |= PARA_STS_ACK;
             s->status |= PARA_STS_ONLINE;
             s->status |= PARA_STS_ERROR;
         }
         else if (val & PARA_CTR_SELECT) {
             if (val & PARA_CTR_STROBE) {
                 s->status &= ~PARA_STS_BUSY;
                 if ((s->control & PARA_CTR_STROBE) == 0)
                     qemu_chr_fe_write(s->chr, &s->dataw, 1);
             } else {
                 if (s->control & PARA_CTR_INTEN) {
                     s->irq_pending = 1;
                 }
             }
         }
         parallel_update_irq(s);
         s->control = val;
         break;
     }
 }

 static void parallel_ioport_write_hw(void *opaque, uint32_t addr, uint32_t val)
 {
     ParallelState *s = opaque;
     uint8_t parm = val;
     int dir;

     /* Sometimes programs do several writes for timing purposes on old
        HW. Take care not to waste time on writes that do nothing. */

     s->last_read_offset = ~0U;

     addr &= 7;
     switch(addr) {
     case PARA_REG_DATA:
         if (s->dataw == val)
             return;
         pdebug("wd%02x\n", val);
         qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_PP_WRITE_DATA, &parm);
         s->dataw = val;
         break;
     case PARA_REG_STS:
         pdebug("ws%02x\n", val);
         if (val & PARA_STS_TMOUT)
             s->epp_timeout = 0;
         break;
     case PARA_REG_CTR:
         val |= 0xc0;
         if (s->control == val)
             return;
         pdebug("wc%02x\n", val);

         if ((val & PARA_CTR_DIR) != (s->control & PARA_CTR_DIR)) {
             if (val & PARA_CTR_DIR) {
                 dir = 1;
             } else {
                 dir = 0;
             }
             qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_PP_DATA_DIR, &dir);
             parm &= ~PARA_CTR_DIR;
         }

         qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_PP_WRITE_CONTROL, &parm);
         s->control = val;
         break;
     case PARA_REG_EPP_ADDR:
         if ((s->control & (PARA_CTR_DIR|PARA_CTR_SIGNAL)) != PARA_CTR_INIT)
             /* Controls not correct for EPP address cycle, so do nothing */
             pdebug("wa%02x s\n", val);
         else {
             struct ParallelIOArg ioarg = { .buffer = &parm, .count = 1 };
             if (qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_PP_EPP_WRITE_ADDR, &ioarg)) {
                 s->epp_timeout = 1;
                 pdebug("wa%02x t\n", val);
             }
             else
                 pdebug("wa%02x\n", val);
         }
         break;
     case PARA_REG_EPP_DATA:
         if ((s->control & (PARA_CTR_DIR|PARA_CTR_SIGNAL)) != PARA_CTR_INIT)
             /* Controls not correct for EPP data cycle, so do nothing */
             pdebug("we%02x s\n", val);
         else {
             struct ParallelIOArg ioarg = { .buffer = &parm, .count = 1 };
             if (qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_PP_EPP_WRITE, &ioarg)) {
                 s->epp_timeout = 1;
                 pdebug("we%02x t\n", val);
             }
             else
                 pdebug("we%02x\n", val);
         }
         break;
     }
 }

 static void
 parallel_ioport_eppdata_write_hw2(void *opaque, uint32_t addr, uint32_t val)
 {
     ParallelState *s = opaque;
     uint16_t eppdata = cpu_to_le16(val);
     int err;
     struct ParallelIOArg ioarg = {
         .buffer = &eppdata, .count = sizeof(eppdata)
     };
     if ((s->control & (PARA_CTR_DIR|PARA_CTR_SIGNAL)) != PARA_CTR_INIT) {
         /* Controls not correct for EPP data cycle, so do nothing */
         pdebug("we%04x s\n", val);
         return;
     }
     err = qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_PP_EPP_WRITE, &ioarg);
     if (err) {
         s->epp_timeout = 1;
         pdebug("we%04x t\n", val);
     }
     else
         pdebug("we%04x\n", val);
 }

 static void
 parallel_ioport_eppdata_write_hw4(void *opaque, uint32_t addr, uint32_t val)
 {
     ParallelState *s = opaque;
     uint32_t eppdata = cpu_to_le32(val);
     int err;
     struct ParallelIOArg ioarg = {
         .buffer = &eppdata, .count = sizeof(eppdata)
     };
     if ((s->control & (PARA_CTR_DIR|PARA_CTR_SIGNAL)) != PARA_CTR_INIT) {
         /* Controls not correct for EPP data cycle, so do nothing */
         pdebug("we%08x s\n", val);
         return;
     }
     err = qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_PP_EPP_WRITE, &ioarg);
     if (err) {
         s->epp_timeout = 1;
         pdebug("we%08x t\n", val);
     }
     else
         pdebug("we%08x\n", val);
 }

 static uint32_t parallel_ioport_read_sw(void *opaque, uint32_t addr)
 {
     ParallelState *s = opaque;
     uint32_t ret = 0xff;

     addr &= 7;
     switch(addr) {
     case PARA_REG_DATA:
         if (s->control & PARA_CTR_DIR)
             ret = s->datar;
         else
             ret = s->dataw;
         break;
     case PARA_REG_STS:
         ret = s->status;
         s->irq_pending = 0;
         if ((s->status & PARA_STS_BUSY) == 0 && (s->control & PARA_CTR_STROBE) == 0) {
             /* XXX Fixme: wait 5 microseconds */
             if (s->status & PARA_STS_ACK)
                 s->status &= ~PARA_STS_ACK;
             else {
                 /* XXX Fixme: wait 5 microseconds */
                 s->status |= PARA_STS_ACK;
                 s->status |= PARA_STS_BUSY;
             }
         }
         parallel_update_irq(s);
         break;
     case PARA_REG_CTR:
         ret = s->control;
         break;
     }
     pdebug("read addr=0x%02x val=0x%02x\n", addr, ret);
     return ret;
 }

 static uint32_t parallel_ioport_read_hw(void *opaque, uint32_t addr)
 {
     ParallelState *s = opaque;
     uint8_t ret = 0xff;
     addr &= 7;
     switch(addr) {
     case PARA_REG_DATA:
         qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_PP_READ_DATA, &ret);
         if (s->last_read_offset != addr || s->datar != ret)
             pdebug("rd%02x\n", ret);
         s->datar = ret;
         break;
     case PARA_REG_STS:
         qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_PP_READ_STATUS, &ret);
         ret &= ~PARA_STS_TMOUT;
         if (s->epp_timeout)
             ret |= PARA_STS_TMOUT;
         if (s->last_read_offset != addr || s->status != ret)
             pdebug("rs%02x\n", ret);
         s->status = ret;
         break;
     case PARA_REG_CTR:
         /* s->control has some bits fixed to 1. It is zero only when
            it has not been yet written to.  */
         if (s->control == 0) {
             qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_PP_READ_CONTROL, &ret);
             if (s->last_read_offset != addr)
                 pdebug("rc%02x\n", ret);
             s->control = ret;
         }
         else {
             ret = s->control;
             if (s->last_read_offset != addr)
                 pdebug("rc%02x\n", ret);
         }
         break;
     case PARA_REG_EPP_ADDR:
         if ((s->control & (PARA_CTR_DIR|PARA_CTR_SIGNAL)) != (PARA_CTR_DIR|PARA_CTR_INIT))
             /* Controls not correct for EPP addr cycle, so do nothing */
             pdebug("ra%02x s\n", ret);
         else {
             struct ParallelIOArg ioarg = { .buffer = &ret, .count = 1 };
             if (qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_PP_EPP_READ_ADDR, &ioarg)) {
                 s->epp_timeout = 1;
                 pdebug("ra%02x t\n", ret);
             }
             else
                 pdebug("ra%02x\n", ret);
         }
         break;
     case PARA_REG_EPP_DATA:
         if ((s->control & (PARA_CTR_DIR|PARA_CTR_SIGNAL)) != (PARA_CTR_DIR|PARA_CTR_INIT))
             /* Controls not correct for EPP data cycle, so do nothing */
             pdebug("re%02x s\n", ret);
         else {
             struct ParallelIOArg ioarg = { .buffer = &ret, .count = 1 };
             if (qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_PP_EPP_READ, &ioarg)) {
                 s->epp_timeout = 1;
                 pdebug("re%02x t\n", ret);
             }
             else
                 pdebug("re%02x\n", ret);
         }
         break;
     }
     s->last_read_offset = addr;
     return ret;
 }

 static uint32_t
 parallel_ioport_eppdata_read_hw2(void *opaque, uint32_t addr)
 {
     ParallelState *s = opaque;
     uint32_t ret;
     uint16_t eppdata = ~0;
     int err;
     struct ParallelIOArg ioarg = {
         .buffer = &eppdata, .count = sizeof(eppdata)
     };
     if ((s->control & (PARA_CTR_DIR|PARA_CTR_SIGNAL)) != (PARA_CTR_DIR|PARA_CTR_INIT)) {
         /* Controls not correct for EPP data cycle, so do nothing */
         pdebug("re%04x s\n", eppdata);
         return eppdata;
     }
     err = qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_PP_EPP_READ, &ioarg);
     ret = le16_to_cpu(eppdata);

     if (err) {
         s->epp_timeout = 1;
         pdebug("re%04x t\n", ret);
     }
     else
         pdebug("re%04x\n", ret);
     return ret;
 }

 static uint32_t
 parallel_ioport_eppdata_read_hw4(void *opaque, uint32_t addr)
 {
     ParallelState *s = opaque;
     uint32_t ret;
     uint32_t eppdata = ~0U;
     int err;
     struct ParallelIOArg ioarg = {
         .buffer = &eppdata, .count = sizeof(eppdata)
     };
     if ((s->control & (PARA_CTR_DIR|PARA_CTR_SIGNAL)) != (PARA_CTR_DIR|PARA_CTR_INIT)) {
         /* Controls not correct for EPP data cycle, so do nothing */
         pdebug("re%08x s\n", eppdata);
         return eppdata;
     }
     err = qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_PP_EPP_READ, &ioarg);
     ret = le32_to_cpu(eppdata);

     if (err) {
         s->epp_timeout = 1;
         pdebug("re%08x t\n", ret);
     }
     else
         pdebug("re%08x\n", ret);
     return ret;
 }

 static void parallel_ioport_ecp_write(void *opaque, uint32_t addr, uint32_t val)
 {
     pdebug("wecp%d=%02x\n", addr & 7, val);
 }

 static uint32_t parallel_ioport_ecp_read(void *opaque, uint32_t addr)
 {
     uint8_t ret = 0xff;

     pdebug("recp%d:%02x\n", addr & 7, ret);
     return ret;
 }

 static void parallel_reset(void *opaque)
 {
     ParallelState *s = opaque;

     s->datar = ~0;
     s->dataw = ~0;
     s->status = PARA_STS_BUSY;
     s->status |= PARA_STS_ACK;
     s->status |= PARA_STS_ONLINE;
     s->status |= PARA_STS_ERROR;
     s->status |= PARA_STS_TMOUT;
     s->control = PARA_CTR_SELECT;
     s->control |= PARA_CTR_INIT;
     s->control |= 0xc0;
     s->irq_pending = 0;
     s->hw_driver = 0;
     s->epp_timeout = 0;
     s->last_read_offset = ~0U;
 }

 static const int isa_parallel_io[MAX_PARALLEL_PORTS] = { 0x378, 0x278, 0x3bc };

 static const MemoryRegionPortio isa_parallel_portio_hw_list[] = {
     { 0, 8, 1,
       .read = parallel_ioport_read_hw,
       .write = parallel_ioport_write_hw },
     { 4, 1, 2,
       .read = parallel_ioport_eppdata_read_hw2,
       .write = parallel_ioport_eppdata_write_hw2 },
     { 4, 1, 4,
       .read = parallel_ioport_eppdata_read_hw4,
       .write = parallel_ioport_eppdata_write_hw4 },
     { 0x400, 8, 1,
       .read = parallel_ioport_ecp_read,
       .write = parallel_ioport_ecp_write },
     PORTIO_END_OF_LIST(),
 };

 static const MemoryRegionPortio isa_parallel_portio_sw_list[] = {
     { 0, 8, 1,
       .read = parallel_ioport_read_sw,
       .write = parallel_ioport_write_sw },
     PORTIO_END_OF_LIST(),
 };

 static int parallel_isa_initfn(ISADevice *dev)
 {
     static int index;
     ISAParallelState *isa = DO_UPCAST(ISAParallelState, dev, dev);
     ParallelState *s = &isa->state;
     int base;
     uint8_t dummy;

     if (!s->chr) {
         fprintf(stderr, "Can't create parallel device, empty char device\n");
         exit(1);
     }

     if (isa->index == -1)
         isa->index = index;
     if (isa->index >= MAX_PARALLEL_PORTS)
         return -1;
     if (isa->iobase == -1)
         isa->iobase = isa_parallel_io[isa->index];
     index++;

     base = isa->iobase;
     isa_init_irq(dev, &s->irq, isa->isairq);
     qemu_register_reset(parallel_reset, s);

     if (qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_PP_READ_STATUS, &dummy) == 0) {
         s->hw_driver = 1;
         s->status = dummy;
     }

     isa_register_portio_list(dev, base,
                              (s->hw_driver
                               ? &isa_parallel_portio_hw_list[0]
                               : &isa_parallel_portio_sw_list[0]),
                              s, "parallel");
     return 0;
 }

 /* Memory mapped interface */
 static uint32_t parallel_mm_readb (void *opaque, hwaddr addr)
 {
     ParallelState *s = opaque;

     return parallel_ioport_read_sw(s, addr >> s->it_shift) & 0xFF;
 }

 static void parallel_mm_writeb (void *opaque,
                                 hwaddr addr, uint32_t value)
 {
     ParallelState *s = opaque;

     parallel_ioport_write_sw(s, addr >> s->it_shift, value & 0xFF);
 }

 static uint32_t parallel_mm_readw (void *opaque, hwaddr addr)
 {
     ParallelState *s = opaque;

     return parallel_ioport_read_sw(s, addr >> s->it_shift) & 0xFFFF;
 }

 static void parallel_mm_writew (void *opaque,
                                 hwaddr addr, uint32_t value)
 {
     ParallelState *s = opaque;

     parallel_ioport_write_sw(s, addr >> s->it_shift, value & 0xFFFF);
 }

 static uint32_t parallel_mm_readl (void *opaque, hwaddr addr)
 {
     ParallelState *s = opaque;

     return parallel_ioport_read_sw(s, addr >> s->it_shift);
 }

 static void parallel_mm_writel (void *opaque,
                                 hwaddr addr, uint32_t value)
 {
     ParallelState *s = opaque;

     parallel_ioport_write_sw(s, addr >> s->it_shift, value);
 }

 static const MemoryRegionOps parallel_mm_ops = {
     .old_mmio = {
         .read = { parallel_mm_readb, parallel_mm_readw, parallel_mm_readl },
         .write = { parallel_mm_writeb, parallel_mm_writew, parallel_mm_writel },
     },
     .endianness = DEVICE_NATIVE_ENDIAN,
 };

 /* If fd is zero, it means that the parallel device uses the console */
 bool parallel_mm_init(MemoryRegion *address_space,
                       hwaddr base, int it_shift, qemu_irq irq,
                       CharDriverState *chr)
 {
     ParallelState *s;

     s = g_malloc0(sizeof(ParallelState));
     s->irq = irq;
     s->chr = chr;
     s->it_shift = it_shift;
     qemu_register_reset(parallel_reset, s);

     memory_region_init_io(&s->iomem, &parallel_mm_ops, s,
                           "parallel", 8 << it_shift);
     memory_region_add_subregion(address_space, base, &s->iomem);
     return true;
 }

 static Property parallel_isa_properties[] = {
     DEFINE_PROP_UINT32("index", ISAParallelState, index,   -1),
     DEFINE_PROP_HEX32("iobase", ISAParallelState, iobase,  -1),
     DEFINE_PROP_UINT32("irq",   ISAParallelState, isairq,  7),
     DEFINE_PROP_CHR("chardev",  ISAParallelState, state.chr),
     DEFINE_PROP_END_OF_LIST(),
 };

 static void parallel_isa_class_initfn(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
     ISADeviceClass *ic = ISA_DEVICE_CLASS(klass);
     ic->init = parallel_isa_initfn;
     dc->props = parallel_isa_properties;
 }

 static const TypeInfo parallel_isa_info = {
     .name          = "isa-parallel",
     .parent        = TYPE_ISA_DEVICE,
     .instance_size = sizeof(ISAParallelState),
     .class_init    = parallel_isa_class_initfn,
 };

 static void parallel_register_types(void)
 {
     type_register_static(&parallel_isa_info);
 }

 type_init(parallel_register_types)
	/*
	* QEMU Parallel PORT emulation
	*
	* Copyright (c) 2003-2005 Fabrice Bellard
	* Copyright (c) 2007 Marko Kohtala
	*
	* Permission is hereby granted, free of charge, to any person obtaining a copy
	* of this software and associated documentation files (the "Software"), to deal
	* in the Software without restriction, including without limitation the rights
	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	* copies of the Software, and to permit persons to whom the Software is
	* furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included in
	* all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
	* THE SOFTWARE.
	*/
	#include "hw.h"
	#include "char/char.h"
	#include "isa.h"
	#include "pc.h"
	#include "sysemu/sysemu.h"

	//#define DEBUG_PARALLEL

	#ifdef DEBUG_PARALLEL
	#define pdebug(fmt, ...) printf("pp: " fmt, ## __VA_ARGS__)
	#else
	#define pdebug(fmt, ...) ((void)0)
	#endif

	#define PARA_REG_DATA 0
	#define PARA_REG_STS 1
	#define PARA_REG_CTR 2
	#define PARA_REG_EPP_ADDR 3
	#define PARA_REG_EPP_DATA 4

	/*
	* These are the definitions for the Printer Status Register
	*/
	#define PARA_STS_BUSY 0x80 /* Busy complement */
	#define PARA_STS_ACK 0x40 /* Acknowledge */
	#define PARA_STS_PAPER 0x20 /* Out of paper */
	#define PARA_STS_ONLINE 0x10 /* Online */
	#define PARA_STS_ERROR 0x08 /* Error complement */
	#define PARA_STS_TMOUT 0x01 /* EPP timeout */

	/*
	* These are the definitions for the Printer Control Register
	*/
	#define PARA_CTR_DIR 0x20 /* Direction (1=read, 0=write) */
	#define PARA_CTR_INTEN 0x10 /* IRQ Enable */
	#define PARA_CTR_SELECT 0x08 /* Select In complement */
	#define PARA_CTR_INIT 0x04 /* Initialize Printer complement */
	#define PARA_CTR_AUTOLF 0x02 /* Auto linefeed complement */
	#define PARA_CTR_STROBE 0x01 /* Strobe complement */

	#define PARA_CTR_SIGNAL (PARA_CTR_SELECT\|PARA_CTR_INIT\|PARA_CTR_AUTOLF\|PARA_CTR_STROBE)

	typedef struct ParallelState {
	MemoryRegion iomem;
	uint8_t dataw;
	uint8_t datar;
	uint8_t status;
	uint8_t control;
	qemu_irq irq;
	int irq_pending;
	CharDriverState *chr;
	int hw_driver;
	int epp_timeout;
	uint32_t last_read_offset; /* For debugging */
	/* Memory-mapped interface */
	int it_shift;
	} ParallelState;

	typedef struct ISAParallelState {
	ISADevice dev;
	uint32_t index;
	uint32_t iobase;
	uint32_t isairq;
	ParallelState state;
	} ISAParallelState;

	static void parallel_update_irq(ParallelState *s)
	{
	if (s->irq_pending)
	qemu_irq_raise(s->irq);
	else
	qemu_irq_lower(s->irq);
	}

	static void
	parallel_ioport_write_sw(void *opaque, uint32_t addr, uint32_t val)
	{
	ParallelState *s = opaque;

	pdebug("write addr=0x%02x val=0x%02x\n", addr, val);

	addr &= 7;
	switch(addr) {
	case PARA_REG_DATA:
	s->dataw = val;
	parallel_update_irq(s);
	break;
	case PARA_REG_CTR:
	val \|= 0xc0;
	if ((val & PARA_CTR_INIT) == 0 ) {
	s->status = PARA_STS_BUSY;
	s->status \|= PARA_STS_ACK;
	s->status \|= PARA_STS_ONLINE;
	s->status \|= PARA_STS_ERROR;
	}
	else if (val & PARA_CTR_SELECT) {
	if (val & PARA_CTR_STROBE) {
	s->status &= ~PARA_STS_BUSY;
	if ((s->control & PARA_CTR_STROBE) == 0)
	qemu_chr_fe_write(s->chr, &s->dataw, 1);
	} else {
	if (s->control & PARA_CTR_INTEN) {
	s->irq_pending = 1;
	}
	}
	}
	parallel_update_irq(s);
	s->control = val;
	break;
	}
	}

	static void parallel_ioport_write_hw(void *opaque, uint32_t addr, uint32_t val)
	{
	ParallelState *s = opaque;
	uint8_t parm = val;
	int dir;

	/* Sometimes programs do several writes for timing purposes on old
	HW. Take care not to waste time on writes that do nothing. */

	s->last_read_offset = ~0U;

	addr &= 7;
	switch(addr) {
	case PARA_REG_DATA:
	if (s->dataw == val)
	return;
	pdebug("wd%02x\n", val);
	qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_PP_WRITE_DATA, &parm);
	s->dataw = val;
	break;
	case PARA_REG_STS:
	pdebug("ws%02x\n", val);
	if (val & PARA_STS_TMOUT)
	s->epp_timeout = 0;
	break;
	case PARA_REG_CTR:
	val \|= 0xc0;
	if (s->control == val)
	return;
	pdebug("wc%02x\n", val);

	if ((val & PARA_CTR_DIR) != (s->control & PARA_CTR_DIR)) {
	if (val & PARA_CTR_DIR) {
	dir = 1;
	} else {
	dir = 0;
	}
	qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_PP_DATA_DIR, &dir);
	parm &= ~PARA_CTR_DIR;
	}

	qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_PP_WRITE_CONTROL, &parm);
	s->control = val;
	break;
	case PARA_REG_EPP_ADDR:
	if ((s->control & (PARA_CTR_DIR\|PARA_CTR_SIGNAL)) != PARA_CTR_INIT)
	/* Controls not correct for EPP address cycle, so do nothing */
	pdebug("wa%02x s\n", val);
	else {
	struct ParallelIOArg ioarg = { .buffer = &parm, .count = 1 };
	if (qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_PP_EPP_WRITE_ADDR, &ioarg)) {
	s->epp_timeout = 1;
	pdebug("wa%02x t\n", val);
	}
	else
	pdebug("wa%02x\n", val);
	}
	break;
	case PARA_REG_EPP_DATA:
	if ((s->control & (PARA_CTR_DIR\|PARA_CTR_SIGNAL)) != PARA_CTR_INIT)
	/* Controls not correct for EPP data cycle, so do nothing */
	pdebug("we%02x s\n", val);
	else {
	struct ParallelIOArg ioarg = { .buffer = &parm, .count = 1 };
	if (qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_PP_EPP_WRITE, &ioarg)) {
	s->epp_timeout = 1;
	pdebug("we%02x t\n", val);
	}
	else
	pdebug("we%02x\n", val);
	}
	break;
	}
	}

	static void
	parallel_ioport_eppdata_write_hw2(void *opaque, uint32_t addr, uint32_t val)
	{
	ParallelState *s = opaque;
	uint16_t eppdata = cpu_to_le16(val);
	int err;
	struct ParallelIOArg ioarg = {
	.buffer = &eppdata, .count = sizeof(eppdata)
	};
	if ((s->control & (PARA_CTR_DIR\|PARA_CTR_SIGNAL)) != PARA_CTR_INIT) {
	/* Controls not correct for EPP data cycle, so do nothing */
	pdebug("we%04x s\n", val);
	return;
	}
	err = qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_PP_EPP_WRITE, &ioarg);
	if (err) {
	s->epp_timeout = 1;
	pdebug("we%04x t\n", val);
	}
	else
	pdebug("we%04x\n", val);
	}

	static void
	parallel_ioport_eppdata_write_hw4(void *opaque, uint32_t addr, uint32_t val)
	{
	ParallelState *s = opaque;
	uint32_t eppdata = cpu_to_le32(val);
	int err;
	struct ParallelIOArg ioarg = {
	.buffer = &eppdata, .count = sizeof(eppdata)
	};
	if ((s->control & (PARA_CTR_DIR\|PARA_CTR_SIGNAL)) != PARA_CTR_INIT) {
	/* Controls not correct for EPP data cycle, so do nothing */
	pdebug("we%08x s\n", val);
	return;
	}
	err = qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_PP_EPP_WRITE, &ioarg);
	if (err) {
	s->epp_timeout = 1;
	pdebug("we%08x t\n", val);
	}
	else
	pdebug("we%08x\n", val);
	}

	static uint32_t parallel_ioport_read_sw(void *opaque, uint32_t addr)
	{
	ParallelState *s = opaque;
	uint32_t ret = 0xff;

	addr &= 7;
	switch(addr) {
	case PARA_REG_DATA:
	if (s->control & PARA_CTR_DIR)
	ret = s->datar;
	else
	ret = s->dataw;
	break;
	case PARA_REG_STS:
	ret = s->status;
	s->irq_pending = 0;
	if ((s->status & PARA_STS_BUSY) == 0 && (s->control & PARA_CTR_STROBE) == 0) {
	/* XXX Fixme: wait 5 microseconds */
	if (s->status & PARA_STS_ACK)
	s->status &= ~PARA_STS_ACK;
	else {
	/* XXX Fixme: wait 5 microseconds */
	s->status \|= PARA_STS_ACK;
	s->status \|= PARA_STS_BUSY;
	}
	}
	parallel_update_irq(s);
	break;
	case PARA_REG_CTR:
	ret = s->control;
	break;
	}
	pdebug("read addr=0x%02x val=0x%02x\n", addr, ret);
	return ret;
	}

	static uint32_t parallel_ioport_read_hw(void *opaque, uint32_t addr)
	{
	ParallelState *s = opaque;
	uint8_t ret = 0xff;
	addr &= 7;
	switch(addr) {
	case PARA_REG_DATA:
	qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_PP_READ_DATA, &ret);
	if (s->last_read_offset != addr \|\| s->datar != ret)
	pdebug("rd%02x\n", ret);
	s->datar = ret;
	break;
	case PARA_REG_STS:
	qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_PP_READ_STATUS, &ret);
	ret &= ~PARA_STS_TMOUT;
	if (s->epp_timeout)
	ret \|= PARA_STS_TMOUT;
	if (s->last_read_offset != addr \|\| s->status != ret)
	pdebug("rs%02x\n", ret);
	s->status = ret;
	break;
	case PARA_REG_CTR:
	/* s->control has some bits fixed to 1. It is zero only when
	it has not been yet written to. */
	if (s->control == 0) {
	qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_PP_READ_CONTROL, &ret);
	if (s->last_read_offset != addr)
	pdebug("rc%02x\n", ret);
	s->control = ret;
	}
	else {
	ret = s->control;
	if (s->last_read_offset != addr)
	pdebug("rc%02x\n", ret);
	}
	break;
	case PARA_REG_EPP_ADDR:
	if ((s->control & (PARA_CTR_DIR\|PARA_CTR_SIGNAL)) != (PARA_CTR_DIR\|PARA_CTR_INIT))
	/* Controls not correct for EPP addr cycle, so do nothing */
	pdebug("ra%02x s\n", ret);
	else {
	struct ParallelIOArg ioarg = { .buffer = &ret, .count = 1 };
	if (qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_PP_EPP_READ_ADDR, &ioarg)) {
	s->epp_timeout = 1;
	pdebug("ra%02x t\n", ret);
	}
	else
	pdebug("ra%02x\n", ret);
	}
	break;
	case PARA_REG_EPP_DATA:
	if ((s->control & (PARA_CTR_DIR\|PARA_CTR_SIGNAL)) != (PARA_CTR_DIR\|PARA_CTR_INIT))
	/* Controls not correct for EPP data cycle, so do nothing */
	pdebug("re%02x s\n", ret);
	else {
	struct ParallelIOArg ioarg = { .buffer = &ret, .count = 1 };
	if (qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_PP_EPP_READ, &ioarg)) {
	s->epp_timeout = 1;
	pdebug("re%02x t\n", ret);
	}
	else
	pdebug("re%02x\n", ret);
	}
	break;
	}
	s->last_read_offset = addr;
	return ret;
	}

	static uint32_t
	parallel_ioport_eppdata_read_hw2(void *opaque, uint32_t addr)
	{
	ParallelState *s = opaque;
	uint32_t ret;
	uint16_t eppdata = ~0;
	int err;
	struct ParallelIOArg ioarg = {
	.buffer = &eppdata, .count = sizeof(eppdata)
	};
	if ((s->control & (PARA_CTR_DIR\|PARA_CTR_SIGNAL)) != (PARA_CTR_DIR\|PARA_CTR_INIT)) {
	/* Controls not correct for EPP data cycle, so do nothing */
	pdebug("re%04x s\n", eppdata);
	return eppdata;
	}
	err = qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_PP_EPP_READ, &ioarg);
	ret = le16_to_cpu(eppdata);

	if (err) {
	s->epp_timeout = 1;
	pdebug("re%04x t\n", ret);
	}
	else
	pdebug("re%04x\n", ret);
	return ret;
	}

	static uint32_t
	parallel_ioport_eppdata_read_hw4(void *opaque, uint32_t addr)
	{
	ParallelState *s = opaque;
	uint32_t ret;
	uint32_t eppdata = ~0U;
	int err;
	struct ParallelIOArg ioarg = {
	.buffer = &eppdata, .count = sizeof(eppdata)
	};
	if ((s->control & (PARA_CTR_DIR\|PARA_CTR_SIGNAL)) != (PARA_CTR_DIR\|PARA_CTR_INIT)) {
	/* Controls not correct for EPP data cycle, so do nothing */
	pdebug("re%08x s\n", eppdata);
	return eppdata;
	}
	err = qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_PP_EPP_READ, &ioarg);
	ret = le32_to_cpu(eppdata);

	if (err) {
	s->epp_timeout = 1;
	pdebug("re%08x t\n", ret);
	}
	else
	pdebug("re%08x\n", ret);
	return ret;
	}

	static void parallel_ioport_ecp_write(void *opaque, uint32_t addr, uint32_t val)
	{
	pdebug("wecp%d=%02x\n", addr & 7, val);
	}

	static uint32_t parallel_ioport_ecp_read(void *opaque, uint32_t addr)
	{
	uint8_t ret = 0xff;

	pdebug("recp%d:%02x\n", addr & 7, ret);
	return ret;
	}

	static void parallel_reset(void *opaque)
	{
	ParallelState *s = opaque;

	s->datar = ~0;
	s->dataw = ~0;
	s->status = PARA_STS_BUSY;
	s->status \|= PARA_STS_ACK;
	s->status \|= PARA_STS_ONLINE;
	s->status \|= PARA_STS_ERROR;
	s->status \|= PARA_STS_TMOUT;
	s->control = PARA_CTR_SELECT;
	s->control \|= PARA_CTR_INIT;
	s->control \|= 0xc0;
	s->irq_pending = 0;
	s->hw_driver = 0;
	s->epp_timeout = 0;
	s->last_read_offset = ~0U;
	}

	static const int isa_parallel_io[MAX_PARALLEL_PORTS] = { 0x378, 0x278, 0x3bc };

	static const MemoryRegionPortio isa_parallel_portio_hw_list[] = {
	{ 0, 8, 1,
	.read = parallel_ioport_read_hw,
	.write = parallel_ioport_write_hw },
	{ 4, 1, 2,
	.read = parallel_ioport_eppdata_read_hw2,
	.write = parallel_ioport_eppdata_write_hw2 },
	{ 4, 1, 4,
	.read = parallel_ioport_eppdata_read_hw4,
	.write = parallel_ioport_eppdata_write_hw4 },
	{ 0x400, 8, 1,
	.read = parallel_ioport_ecp_read,
	.write = parallel_ioport_ecp_write },
	PORTIO_END_OF_LIST(),
	};

	static const MemoryRegionPortio isa_parallel_portio_sw_list[] = {
	{ 0, 8, 1,
	.read = parallel_ioport_read_sw,
	.write = parallel_ioport_write_sw },
	PORTIO_END_OF_LIST(),
	};

	static int parallel_isa_initfn(ISADevice *dev)
	{
	static int index;
	ISAParallelState *isa = DO_UPCAST(ISAParallelState, dev, dev);
	ParallelState *s = &isa->state;
	int base;
	uint8_t dummy;

	if (!s->chr) {
	fprintf(stderr, "Can't create parallel device, empty char device\n");
	exit(1);
	}

	if (isa->index == -1)
	isa->index = index;
	if (isa->index >= MAX_PARALLEL_PORTS)
	return -1;
	if (isa->iobase == -1)
	isa->iobase = isa_parallel_io[isa->index];
	index++;

	base = isa->iobase;
	isa_init_irq(dev, &s->irq, isa->isairq);
	qemu_register_reset(parallel_reset, s);

	if (qemu_chr_fe_ioctl(s->chr, CHR_IOCTL_PP_READ_STATUS, &dummy) == 0) {
	s->hw_driver = 1;
	s->status = dummy;
	}

	isa_register_portio_list(dev, base,
	(s->hw_driver
	? &isa_parallel_portio_hw_list[0]
	: &isa_parallel_portio_sw_list[0]),
	s, "parallel");
	return 0;
	}

	/* Memory mapped interface */
	static uint32_t parallel_mm_readb (void *opaque, hwaddr addr)
	{
	ParallelState *s = opaque;

	return parallel_ioport_read_sw(s, addr >> s->it_shift) & 0xFF;
	}

	static void parallel_mm_writeb (void *opaque,
	hwaddr addr, uint32_t value)
	{
	ParallelState *s = opaque;

	parallel_ioport_write_sw(s, addr >> s->it_shift, value & 0xFF);
	}

	static uint32_t parallel_mm_readw (void *opaque, hwaddr addr)
	{
	ParallelState *s = opaque;

	return parallel_ioport_read_sw(s, addr >> s->it_shift) & 0xFFFF;
	}

	static void parallel_mm_writew (void *opaque,
	hwaddr addr, uint32_t value)
	{
	ParallelState *s = opaque;

	parallel_ioport_write_sw(s, addr >> s->it_shift, value & 0xFFFF);
	}

	static uint32_t parallel_mm_readl (void *opaque, hwaddr addr)
	{
	ParallelState *s = opaque;

	return parallel_ioport_read_sw(s, addr >> s->it_shift);
	}

	static void parallel_mm_writel (void *opaque,
	hwaddr addr, uint32_t value)
	{
	ParallelState *s = opaque;

	parallel_ioport_write_sw(s, addr >> s->it_shift, value);
	}

	static const MemoryRegionOps parallel_mm_ops = {
	.old_mmio = {
	.read = { parallel_mm_readb, parallel_mm_readw, parallel_mm_readl },
	.write = { parallel_mm_writeb, parallel_mm_writew, parallel_mm_writel },
	},
	.endianness = DEVICE_NATIVE_ENDIAN,
	};

	/* If fd is zero, it means that the parallel device uses the console */
	bool parallel_mm_init(MemoryRegion *address_space,
	hwaddr base, int it_shift, qemu_irq irq,
	CharDriverState *chr)
	{
	ParallelState *s;

	s = g_malloc0(sizeof(ParallelState));
	s->irq = irq;
	s->chr = chr;
	s->it_shift = it_shift;
	qemu_register_reset(parallel_reset, s);

	memory_region_init_io(&s->iomem, &parallel_mm_ops, s,
	"parallel", 8 << it_shift);
	memory_region_add_subregion(address_space, base, &s->iomem);
	return true;
	}

	static Property parallel_isa_properties[] = {
	DEFINE_PROP_UINT32("index", ISAParallelState, index, -1),
	DEFINE_PROP_HEX32("iobase", ISAParallelState, iobase, -1),
	DEFINE_PROP_UINT32("irq", ISAParallelState, isairq, 7),
	DEFINE_PROP_CHR("chardev", ISAParallelState, state.chr),
	DEFINE_PROP_END_OF_LIST(),
	};

	static void parallel_isa_class_initfn(ObjectClass klass, void data)
	{
	DeviceClass *dc = DEVICE_CLASS(klass);
	ISADeviceClass *ic = ISA_DEVICE_CLASS(klass);
	ic->init = parallel_isa_initfn;
	dc->props = parallel_isa_properties;
	}

	static const TypeInfo parallel_isa_info = {
	.name = "isa-parallel",
	.parent = TYPE_ISA_DEVICE,
	.instance_size = sizeof(ISAParallelState),
	.class_init = parallel_isa_class_initfn,
	};

	static void parallel_register_types(void)
	{
	type_register_static(&parallel_isa_info);
	}

	type_init(parallel_register_types)