shakti_uart.c (5753B)
1 /* 2 * SHAKTI UART 3 * 4 * Copyright (c) 2021 Vijai Kumar K <vijai@behindbytes.com> 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 25 #include "qemu/osdep.h" 26 #include "hw/char/shakti_uart.h" 27 #include "hw/qdev-properties.h" 28 #include "hw/qdev-properties-system.h" 29 #include "qemu/log.h" 30 31 static uint64_t shakti_uart_read(void *opaque, hwaddr addr, unsigned size) 32 { 33 ShaktiUartState *s = opaque; 34 35 switch (addr) { 36 case SHAKTI_UART_BAUD: 37 return s->uart_baud; 38 case SHAKTI_UART_RX: 39 qemu_chr_fe_accept_input(&s->chr); 40 s->uart_status &= ~SHAKTI_UART_STATUS_RX_NOT_EMPTY; 41 return s->uart_rx; 42 case SHAKTI_UART_STATUS: 43 return s->uart_status; 44 case SHAKTI_UART_DELAY: 45 return s->uart_delay; 46 case SHAKTI_UART_CONTROL: 47 return s->uart_control; 48 case SHAKTI_UART_INT_EN: 49 return s->uart_interrupt; 50 case SHAKTI_UART_IQ_CYCLES: 51 return s->uart_iq_cycles; 52 case SHAKTI_UART_RX_THRES: 53 return s->uart_rx_threshold; 54 default: 55 /* Also handles TX REG which is write only */ 56 qemu_log_mask(LOG_GUEST_ERROR, 57 "%s: Bad offset 0x%"HWADDR_PRIx"\n", __func__, addr); 58 } 59 60 return 0; 61 } 62 63 static void shakti_uart_write(void *opaque, hwaddr addr, 64 uint64_t data, unsigned size) 65 { 66 ShaktiUartState *s = opaque; 67 uint32_t value = data; 68 uint8_t ch; 69 70 switch (addr) { 71 case SHAKTI_UART_BAUD: 72 s->uart_baud = value; 73 break; 74 case SHAKTI_UART_TX: 75 ch = value; 76 qemu_chr_fe_write_all(&s->chr, &ch, 1); 77 s->uart_status &= ~SHAKTI_UART_STATUS_TX_FULL; 78 break; 79 case SHAKTI_UART_STATUS: 80 s->uart_status = value; 81 break; 82 case SHAKTI_UART_DELAY: 83 s->uart_delay = value; 84 break; 85 case SHAKTI_UART_CONTROL: 86 s->uart_control = value; 87 break; 88 case SHAKTI_UART_INT_EN: 89 s->uart_interrupt = value; 90 break; 91 case SHAKTI_UART_IQ_CYCLES: 92 s->uart_iq_cycles = value; 93 break; 94 case SHAKTI_UART_RX_THRES: 95 s->uart_rx_threshold = value; 96 break; 97 default: 98 qemu_log_mask(LOG_GUEST_ERROR, 99 "%s: Bad offset 0x%"HWADDR_PRIx"\n", __func__, addr); 100 } 101 } 102 103 static const MemoryRegionOps shakti_uart_ops = { 104 .read = shakti_uart_read, 105 .write = shakti_uart_write, 106 .endianness = DEVICE_NATIVE_ENDIAN, 107 .impl = {.min_access_size = 1, .max_access_size = 4}, 108 .valid = {.min_access_size = 1, .max_access_size = 4}, 109 }; 110 111 static void shakti_uart_reset(DeviceState *dev) 112 { 113 ShaktiUartState *s = SHAKTI_UART(dev); 114 115 s->uart_baud = SHAKTI_UART_BAUD_DEFAULT; 116 s->uart_tx = 0x0; 117 s->uart_rx = 0x0; 118 s->uart_status = 0x0000; 119 s->uart_delay = 0x0000; 120 s->uart_control = SHAKTI_UART_CONTROL_DEFAULT; 121 s->uart_interrupt = 0x0000; 122 s->uart_iq_cycles = 0x00; 123 s->uart_rx_threshold = 0x00; 124 } 125 126 static int shakti_uart_can_receive(void *opaque) 127 { 128 ShaktiUartState *s = opaque; 129 130 return !(s->uart_status & SHAKTI_UART_STATUS_RX_NOT_EMPTY); 131 } 132 133 static void shakti_uart_receive(void *opaque, const uint8_t *buf, int size) 134 { 135 ShaktiUartState *s = opaque; 136 137 s->uart_rx = *buf; 138 s->uart_status |= SHAKTI_UART_STATUS_RX_NOT_EMPTY; 139 } 140 141 static void shakti_uart_realize(DeviceState *dev, Error **errp) 142 { 143 ShaktiUartState *sus = SHAKTI_UART(dev); 144 qemu_chr_fe_set_handlers(&sus->chr, shakti_uart_can_receive, 145 shakti_uart_receive, NULL, NULL, sus, NULL, true); 146 } 147 148 static void shakti_uart_instance_init(Object *obj) 149 { 150 ShaktiUartState *sus = SHAKTI_UART(obj); 151 memory_region_init_io(&sus->mmio, 152 obj, 153 &shakti_uart_ops, 154 sus, 155 TYPE_SHAKTI_UART, 156 0x1000); 157 sysbus_init_mmio(SYS_BUS_DEVICE(obj), &sus->mmio); 158 } 159 160 static Property shakti_uart_properties[] = { 161 DEFINE_PROP_CHR("chardev", ShaktiUartState, chr), 162 DEFINE_PROP_END_OF_LIST(), 163 }; 164 165 static void shakti_uart_class_init(ObjectClass *klass, void *data) 166 { 167 DeviceClass *dc = DEVICE_CLASS(klass); 168 dc->reset = shakti_uart_reset; 169 dc->realize = shakti_uart_realize; 170 device_class_set_props(dc, shakti_uart_properties); 171 set_bit(DEVICE_CATEGORY_INPUT, dc->categories); 172 } 173 174 static const TypeInfo shakti_uart_info = { 175 .name = TYPE_SHAKTI_UART, 176 .parent = TYPE_SYS_BUS_DEVICE, 177 .instance_size = sizeof(ShaktiUartState), 178 .class_init = shakti_uart_class_init, 179 .instance_init = shakti_uart_instance_init, 180 }; 181 182 static void shakti_uart_register_types(void) 183 { 184 type_register_static(&shakti_uart_info); 185 } 186 type_init(shakti_uart_register_types)