1 /* 2 * QEMU model of the Canon DIGIC UART block. 3 * 4 * Copyright (C) 2013 Antony Pavlov <antonynpavlov@gmail.com> 5 * 6 * This model is based on reverse engineering efforts 7 * made by CHDK (http://chdk.wikia.com) and 8 * Magic Lantern (http://www.magiclantern.fm) projects 9 * contributors. 10 * 11 * See "Serial terminal" docs here: 12 * http://magiclantern.wikia.com/wiki/Register_Map#Misc_Registers 13 * 14 * The QEMU model of the Milkymist UART block by Michael Walle 15 * is used as a template. 16 * 17 * This program is free software; you can redistribute it and/or modify 18 * it under the terms of the GNU General Public License as published by 19 * the Free Software Foundation; either version 2 of the License, or 20 * (at your option) any later version. 21 * 22 * This program is distributed in the hope that it will be useful, 23 * but WITHOUT ANY WARRANTY; without even the implied warranty of 24 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 25 * GNU General Public License for more details. 26 * 27 */ 28 29 #include "qemu/osdep.h" 30 #include "hw/sysbus.h" 31 #include "migration/vmstate.h" 32 #include "chardev/char-fe.h" 33 #include "qemu/log.h" 34 #include "qemu/module.h" 35 36 #include "hw/char/digic-uart.h" 37 #include "hw/qdev-properties.h" 38 #include "hw/qdev-properties-system.h" 39 40 enum { 41 ST_RX_RDY = (1 << 0), 42 ST_TX_RDY = (1 << 1), 43 }; 44 45 static uint64_t digic_uart_read(void *opaque, hwaddr addr, 46 unsigned size) 47 { 48 DigicUartState *s = opaque; 49 uint64_t ret = 0; 50 51 addr >>= 2; 52 53 switch (addr) { 54 case R_RX: 55 s->reg_st &= ~(ST_RX_RDY); 56 ret = s->reg_rx; 57 break; 58 59 case R_ST: 60 ret = s->reg_st; 61 break; 62 63 default: 64 qemu_log_mask(LOG_UNIMP, 65 "digic-uart: read access to unknown register 0x" 66 TARGET_FMT_plx "\n", addr << 2); 67 } 68 69 return ret; 70 } 71 72 static void digic_uart_write(void *opaque, hwaddr addr, uint64_t value, 73 unsigned size) 74 { 75 DigicUartState *s = opaque; 76 unsigned char ch = value; 77 78 addr >>= 2; 79 80 switch (addr) { 81 case R_TX: 82 /* XXX this blocks entire thread. Rewrite to use 83 * qemu_chr_fe_write and background I/O callbacks */ 84 qemu_chr_fe_write_all(&s->chr, &ch, 1); 85 break; 86 87 case R_ST: 88 /* 89 * Ignore write to R_ST. 90 * 91 * The point is that this register is actively used 92 * during receiving and transmitting symbols, 93 * but we don't know the function of most of bits. 94 * 95 * Ignoring writes to R_ST is only a simplification 96 * of the model. It has no perceptible side effects 97 * for existing guests. 98 */ 99 break; 100 101 default: 102 qemu_log_mask(LOG_UNIMP, 103 "digic-uart: write access to unknown register 0x" 104 TARGET_FMT_plx "\n", addr << 2); 105 } 106 } 107 108 static const MemoryRegionOps uart_mmio_ops = { 109 .read = digic_uart_read, 110 .write = digic_uart_write, 111 .valid = { 112 .min_access_size = 4, 113 .max_access_size = 4, 114 }, 115 .endianness = DEVICE_NATIVE_ENDIAN, 116 }; 117 118 static int uart_can_rx(void *opaque) 119 { 120 DigicUartState *s = opaque; 121 122 return !(s->reg_st & ST_RX_RDY); 123 } 124 125 static void uart_rx(void *opaque, const uint8_t *buf, int size) 126 { 127 DigicUartState *s = opaque; 128 129 assert(uart_can_rx(opaque)); 130 131 s->reg_st |= ST_RX_RDY; 132 s->reg_rx = *buf; 133 } 134 135 static void uart_event(void *opaque, QEMUChrEvent event) 136 { 137 } 138 139 static void digic_uart_reset(DeviceState *d) 140 { 141 DigicUartState *s = DIGIC_UART(d); 142 143 s->reg_rx = 0; 144 s->reg_st = ST_TX_RDY; 145 } 146 147 static void digic_uart_realize(DeviceState *dev, Error **errp) 148 { 149 DigicUartState *s = DIGIC_UART(dev); 150 151 qemu_chr_fe_set_handlers(&s->chr, uart_can_rx, uart_rx, 152 uart_event, NULL, s, NULL, true); 153 } 154 155 static void digic_uart_init(Object *obj) 156 { 157 DigicUartState *s = DIGIC_UART(obj); 158 159 memory_region_init_io(&s->regs_region, OBJECT(s), &uart_mmio_ops, s, 160 TYPE_DIGIC_UART, 0x18); 161 sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->regs_region); 162 } 163 164 static const VMStateDescription vmstate_digic_uart = { 165 .name = "digic-uart", 166 .version_id = 1, 167 .minimum_version_id = 1, 168 .fields = (VMStateField[]) { 169 VMSTATE_UINT32(reg_rx, DigicUartState), 170 VMSTATE_UINT32(reg_st, DigicUartState), 171 VMSTATE_END_OF_LIST() 172 } 173 }; 174 175 static Property digic_uart_properties[] = { 176 DEFINE_PROP_CHR("chardev", DigicUartState, chr), 177 DEFINE_PROP_END_OF_LIST(), 178 }; 179 180 static void digic_uart_class_init(ObjectClass *klass, void *data) 181 { 182 DeviceClass *dc = DEVICE_CLASS(klass); 183 184 dc->realize = digic_uart_realize; 185 dc->reset = digic_uart_reset; 186 dc->vmsd = &vmstate_digic_uart; 187 device_class_set_props(dc, digic_uart_properties); 188 } 189 190 static const TypeInfo digic_uart_info = { 191 .name = TYPE_DIGIC_UART, 192 .parent = TYPE_SYS_BUS_DEVICE, 193 .instance_size = sizeof(DigicUartState), 194 .instance_init = digic_uart_init, 195 .class_init = digic_uart_class_init, 196 }; 197 198 static void digic_uart_register_types(void) 199 { 200 type_register_static(&digic_uart_info); 201 } 202 203 type_init(digic_uart_register_types) 204