diff options
Diffstat (limited to 'hw/char/nrf51_uart.c')
| -rw-r--r-- | hw/char/nrf51_uart.c | 335 |
1 files changed, 335 insertions, 0 deletions
diff --git a/hw/char/nrf51_uart.c b/hw/char/nrf51_uart.c new file mode 100644 index 000000000..3c6f982de --- /dev/null +++ b/hw/char/nrf51_uart.c @@ -0,0 +1,335 @@ +/* + * nRF51 SoC UART emulation + * + * See nRF51 Series Reference Manual, "29 Universal Asynchronous + * Receiver/Transmitter" for hardware specifications: + * http://infocenter.nordicsemi.com/pdf/nRF51_RM_v3.0.pdf + * + * Copyright (c) 2018 Julia Suvorova <jusual@mail.ru> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 or + * (at your option) any later version. + */ + +#include "qemu/osdep.h" +#include "qemu/log.h" +#include "qemu/module.h" +#include "hw/char/nrf51_uart.h" +#include "hw/irq.h" +#include "hw/qdev-properties.h" +#include "hw/qdev-properties-system.h" +#include "migration/vmstate.h" +#include "trace.h" + +static void nrf51_uart_update_irq(NRF51UARTState *s) +{ + bool irq = false; + + irq |= (s->reg[R_UART_RXDRDY] && + (s->reg[R_UART_INTEN] & R_UART_INTEN_RXDRDY_MASK)); + irq |= (s->reg[R_UART_TXDRDY] && + (s->reg[R_UART_INTEN] & R_UART_INTEN_TXDRDY_MASK)); + irq |= (s->reg[R_UART_ERROR] && + (s->reg[R_UART_INTEN] & R_UART_INTEN_ERROR_MASK)); + irq |= (s->reg[R_UART_RXTO] && + (s->reg[R_UART_INTEN] & R_UART_INTEN_RXTO_MASK)); + + qemu_set_irq(s->irq, irq); +} + +static uint64_t uart_read(void *opaque, hwaddr addr, unsigned int size) +{ + NRF51UARTState *s = NRF51_UART(opaque); + uint64_t r; + + if (!s->enabled) { + return 0; + } + + switch (addr) { + case A_UART_RXD: + r = s->rx_fifo[s->rx_fifo_pos]; + if (s->rx_started && s->rx_fifo_len) { + s->rx_fifo_pos = (s->rx_fifo_pos + 1) % UART_FIFO_LENGTH; + s->rx_fifo_len--; + if (s->rx_fifo_len) { + s->reg[R_UART_RXDRDY] = 1; + nrf51_uart_update_irq(s); + } + qemu_chr_fe_accept_input(&s->chr); + } + break; + case A_UART_INTENSET: + case A_UART_INTENCLR: + case A_UART_INTEN: + r = s->reg[R_UART_INTEN]; + break; + default: + r = s->reg[addr / 4]; + break; + } + + trace_nrf51_uart_read(addr, r, size); + + return r; +} + +static gboolean uart_transmit(void *do_not_use, GIOCondition cond, void *opaque) +{ + NRF51UARTState *s = NRF51_UART(opaque); + int r; + uint8_t c = s->reg[R_UART_TXD]; + + s->watch_tag = 0; + + r = qemu_chr_fe_write(&s->chr, &c, 1); + if (r <= 0) { + s->watch_tag = qemu_chr_fe_add_watch(&s->chr, G_IO_OUT | G_IO_HUP, + uart_transmit, s); + if (!s->watch_tag) { + /* The hardware has no transmit error reporting, + * so silently drop the byte + */ + goto buffer_drained; + } + return FALSE; + } + +buffer_drained: + s->reg[R_UART_TXDRDY] = 1; + s->pending_tx_byte = false; + return FALSE; +} + +static void uart_cancel_transmit(NRF51UARTState *s) +{ + if (s->watch_tag) { + g_source_remove(s->watch_tag); + s->watch_tag = 0; + } +} + +static void uart_write(void *opaque, hwaddr addr, + uint64_t value, unsigned int size) +{ + NRF51UARTState *s = NRF51_UART(opaque); + + trace_nrf51_uart_write(addr, value, size); + + if (!s->enabled && (addr != A_UART_ENABLE)) { + return; + } + + switch (addr) { + case A_UART_TXD: + if (!s->pending_tx_byte && s->tx_started) { + s->reg[R_UART_TXD] = value; + s->pending_tx_byte = true; + uart_transmit(NULL, G_IO_OUT, s); + } + break; + case A_UART_INTEN: + s->reg[R_UART_INTEN] = value; + break; + case A_UART_INTENSET: + s->reg[R_UART_INTEN] |= value; + break; + case A_UART_INTENCLR: + s->reg[R_UART_INTEN] &= ~value; + break; + case A_UART_TXDRDY ... A_UART_RXTO: + s->reg[addr / 4] = value; + break; + case A_UART_ERRORSRC: + s->reg[addr / 4] &= ~value; + break; + case A_UART_RXD: + break; + case A_UART_RXDRDY: + if (value == 0) { + s->reg[R_UART_RXDRDY] = 0; + } + break; + case A_UART_STARTTX: + if (value == 1) { + s->tx_started = true; + } + break; + case A_UART_STARTRX: + if (value == 1) { + s->rx_started = true; + } + break; + case A_UART_ENABLE: + if (value) { + if (value == 4) { + s->enabled = true; + } + break; + } + s->enabled = false; + value = 1; + /* fall through */ + case A_UART_SUSPEND: + case A_UART_STOPTX: + if (value == 1) { + s->tx_started = false; + } + /* fall through */ + case A_UART_STOPRX: + if (addr != A_UART_STOPTX && value == 1) { + s->rx_started = false; + s->reg[R_UART_RXTO] = 1; + } + break; + default: + s->reg[addr / 4] = value; + break; + } + nrf51_uart_update_irq(s); +} + +static const MemoryRegionOps uart_ops = { + .read = uart_read, + .write = uart_write, + .endianness = DEVICE_LITTLE_ENDIAN, +}; + +static void nrf51_uart_reset(DeviceState *dev) +{ + NRF51UARTState *s = NRF51_UART(dev); + + s->pending_tx_byte = 0; + + uart_cancel_transmit(s); + + memset(s->reg, 0, sizeof(s->reg)); + + s->reg[R_UART_PSELRTS] = 0xFFFFFFFF; + s->reg[R_UART_PSELTXD] = 0xFFFFFFFF; + s->reg[R_UART_PSELCTS] = 0xFFFFFFFF; + s->reg[R_UART_PSELRXD] = 0xFFFFFFFF; + s->reg[R_UART_BAUDRATE] = 0x4000000; + + s->rx_fifo_len = 0; + s->rx_fifo_pos = 0; + s->rx_started = false; + s->tx_started = false; + s->enabled = false; +} + +static void uart_receive(void *opaque, const uint8_t *buf, int size) +{ + + NRF51UARTState *s = NRF51_UART(opaque); + int i; + + if (size == 0 || s->rx_fifo_len >= UART_FIFO_LENGTH) { + return; + } + + for (i = 0; i < size; i++) { + uint32_t pos = (s->rx_fifo_pos + s->rx_fifo_len) % UART_FIFO_LENGTH; + s->rx_fifo[pos] = buf[i]; + s->rx_fifo_len++; + } + + s->reg[R_UART_RXDRDY] = 1; + nrf51_uart_update_irq(s); +} + +static int uart_can_receive(void *opaque) +{ + NRF51UARTState *s = NRF51_UART(opaque); + + return s->rx_started ? (UART_FIFO_LENGTH - s->rx_fifo_len) : 0; +} + +static void uart_event(void *opaque, QEMUChrEvent event) +{ + NRF51UARTState *s = NRF51_UART(opaque); + + if (event == CHR_EVENT_BREAK) { + s->reg[R_UART_ERRORSRC] |= 3; + s->reg[R_UART_ERROR] = 1; + nrf51_uart_update_irq(s); + } +} + +static void nrf51_uart_realize(DeviceState *dev, Error **errp) +{ + NRF51UARTState *s = NRF51_UART(dev); + + qemu_chr_fe_set_handlers(&s->chr, uart_can_receive, uart_receive, + uart_event, NULL, s, NULL, true); +} + +static void nrf51_uart_init(Object *obj) +{ + NRF51UARTState *s = NRF51_UART(obj); + SysBusDevice *sbd = SYS_BUS_DEVICE(obj); + + memory_region_init_io(&s->iomem, obj, &uart_ops, s, + "nrf51_soc.uart", UART_SIZE); + sysbus_init_mmio(sbd, &s->iomem); + sysbus_init_irq(sbd, &s->irq); +} + +static int nrf51_uart_post_load(void *opaque, int version_id) +{ + NRF51UARTState *s = NRF51_UART(opaque); + + if (s->pending_tx_byte) { + s->watch_tag = qemu_chr_fe_add_watch(&s->chr, G_IO_OUT | G_IO_HUP, + uart_transmit, s); + } + + return 0; +} + +static const VMStateDescription nrf51_uart_vmstate = { + .name = "nrf51_soc.uart", + .post_load = nrf51_uart_post_load, + .fields = (VMStateField[]) { + VMSTATE_UINT32_ARRAY(reg, NRF51UARTState, 0x56C), + VMSTATE_UINT8_ARRAY(rx_fifo, NRF51UARTState, UART_FIFO_LENGTH), + VMSTATE_UINT32(rx_fifo_pos, NRF51UARTState), + VMSTATE_UINT32(rx_fifo_len, NRF51UARTState), + VMSTATE_BOOL(rx_started, NRF51UARTState), + VMSTATE_BOOL(tx_started, NRF51UARTState), + VMSTATE_BOOL(pending_tx_byte, NRF51UARTState), + VMSTATE_BOOL(enabled, NRF51UARTState), + VMSTATE_END_OF_LIST() + } +}; + +static Property nrf51_uart_properties[] = { + DEFINE_PROP_CHR("chardev", NRF51UARTState, chr), + DEFINE_PROP_END_OF_LIST(), +}; + +static void nrf51_uart_class_init(ObjectClass *klass, void *data) +{ + DeviceClass *dc = DEVICE_CLASS(klass); + + dc->reset = nrf51_uart_reset; + dc->realize = nrf51_uart_realize; + device_class_set_props(dc, nrf51_uart_properties); + dc->vmsd = &nrf51_uart_vmstate; +} + +static const TypeInfo nrf51_uart_info = { + .name = TYPE_NRF51_UART, + .parent = TYPE_SYS_BUS_DEVICE, + .instance_size = sizeof(NRF51UARTState), + .instance_init = nrf51_uart_init, + .class_init = nrf51_uart_class_init +}; + +static void nrf51_uart_register_types(void) +{ + type_register_static(&nrf51_uart_info); +} + +type_init(nrf51_uart_register_types) |