hw/lm32_juart.c

   1 /*
   2  *  LatticeMico32 JTAG UART model.
   3  *
   4  *  Copyright (c) 2010 Michael Walle <michael@walle.cc>
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include "hw.h"
  21 #include "sysbus.h"
  22 #include "trace.h"
  23 #include "qemu-char.h"
  24
  25 #include "lm32_juart.h"
  26
  27 enum {
  28     LM32_JUART_MIN_SAVE_VERSION = 0,
  29     LM32_JUART_CURRENT_SAVE_VERSION = 0,
  30     LM32_JUART_MAX_SAVE_VERSION = 0,
  31 };
  32
  33 enum {
  34     JTX_FULL = (1<<8),
  35 };
  36
  37 enum {
  38     JRX_FULL = (1<<8),
  39 };
  40
  41 struct LM32JuartState {
  42     SysBusDevice busdev;
  43     CharDriverState *chr;
  44
  45     uint32_t jtx;
  46     uint32_t jrx;
  47 };
  48 typedef struct LM32JuartState LM32JuartState;
  49
  50 static void juart_update_handlers(LM32JuartState *s);
  51
  52 uint32_t lm32_juart_get_jtx(DeviceState *d)
  53 {
  54     LM32JuartState *s = container_of(d, LM32JuartState, busdev.qdev);
  55
  56     trace_lm32_juart_get_jtx(s->jtx);
  57     return s->jtx;
  58 }
  59
  60 uint32_t lm32_juart_get_jrx(DeviceState *d)
  61 {
  62     LM32JuartState *s = container_of(d, LM32JuartState, busdev.qdev);
  63
  64     trace_lm32_juart_get_jrx(s->jrx);
  65     return s->jrx;
  66 }
  67
  68 void lm32_juart_set_jtx(DeviceState *d, uint32_t jtx)
  69 {
  70     LM32JuartState *s = container_of(d, LM32JuartState, busdev.qdev);
  71     unsigned char ch = jtx & 0xff;
  72
  73     trace_lm32_juart_set_jtx(s->jtx);
  74
  75     s->jtx = jtx;
  76     if (s->chr) {
  77         qemu_chr_fe_write(s->chr, &ch, 1);
  78     }
  79 }
  80
  81 void lm32_juart_set_jrx(DeviceState *d, uint32_t jtx)
  82 {
  83     LM32JuartState *s = container_of(d, LM32JuartState, busdev.qdev);
  84
  85     trace_lm32_juart_set_jrx(s->jrx);
  86     s->jrx &= ~JRX_FULL;
  87     juart_update_handlers(s);
  88 }
  89
  90 static void juart_rx(LM32JuartState *s, const uint8_t *buf, int size)
  91 {
  92     s->jrx = *buf | JRX_FULL;
  93     juart_update_handlers(s);
  94 }
  95
  96 static int juart_can_rx(LM32JuartState *s)
  97 {
  98     return !(s->jrx & JRX_FULL);
  99 }
 100
 101 static void juart_rx_handler(void *opaque)
 102 {
 103     LM32JuartState *s = opaque;
 104     uint8_t buf[32];
 105     int size;
 106
 107     size = juart_can_rx(s);
 108     size = MIN(size, sizeof(buf));
 109     size = qemu_chr_fe_read(s->chr, buf, size);
 110
 111     juart_rx(s, buf, size);
 112 }
 113
 114 static void juart_update_handlers(LM32JuartState *s)
 115 {
 116     if (juart_can_rx(s) > 0) {
 117         qemu_chr_fe_set_handlers(s->chr, juart_rx_handler, NULL, NULL, s);
 118     } else {
 119         qemu_chr_fe_set_handlers(s->chr, NULL, NULL, NULL, s);
 120     }
 121 }
 122
 123 static void juart_reset(DeviceState *d)
 124 {
 125     LM32JuartState *s = container_of(d, LM32JuartState, busdev.qdev);
 126
 127     s->jtx = 0;
 128     s->jrx = 0;
 129     juart_update_handlers(s);
 130 }
 131
 132 static int lm32_juart_init(SysBusDevice *dev)
 133 {
 134     LM32JuartState *s = FROM_SYSBUS(typeof(*s), dev);
 135
 136     s->chr = qdev_init_chardev(&dev->qdev);
 137     if (s->chr) {
 138         qemu_chr_fe_open(s->chr);
 139         juart_update_handlers(s);
 140     }
 141
 142     return 0;
 143 }
 144
 145 static const VMStateDescription vmstate_lm32_juart = {
 146     .name = "lm32-juart",
 147     .version_id = 1,
 148     .minimum_version_id = 1,
 149     .minimum_version_id_old = 1,
 150     .fields      = (VMStateField[]) {
 151         VMSTATE_UINT32(jtx, LM32JuartState),
 152         VMSTATE_UINT32(jrx, LM32JuartState),
 153         VMSTATE_END_OF_LIST()
 154     }
 155 };
 156
 157 static SysBusDeviceInfo lm32_juart_info = {
 158     .init = lm32_juart_init,
 159     .qdev.name  = "lm32-juart",
 160     .qdev.size  = sizeof(LM32JuartState),
 161     .qdev.vmsd  = &vmstate_lm32_juart,
 162     .qdev.reset = juart_reset,
 163 };
 164
 165 static void lm32_juart_register(void)
 166 {
 167     sysbus_register_withprop(&lm32_juart_info);
 168 }
 169
 170 device_init(lm32_juart_register)