diff options
Diffstat (limited to 'hw/char/ibex_uart.c')
| -rw-r--r-- | hw/char/ibex_uart.c | 492 |
1 files changed, 492 insertions, 0 deletions
diff --git a/hw/char/ibex_uart.c b/hw/char/ibex_uart.c new file mode 100644 index 0000000000..3e0dd9968e --- /dev/null +++ b/hw/char/ibex_uart.c @@ -0,0 +1,492 @@ +/* + * QEMU lowRISC Ibex UART device + * + * Copyright (c) 2020 Western Digital + * + * For details check the documentation here: + * https://docs.opentitan.org/hw/ip/uart/doc/ + * + * 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 "qemu/osdep.h" +#include "hw/char/ibex_uart.h" +#include "hw/irq.h" +#include "hw/qdev-properties.h" +#include "migration/vmstate.h" +#include "qemu/log.h" +#include "qemu/module.h" + +static void ibex_uart_update_irqs(IbexUartState *s) +{ + if (s->uart_intr_state & s->uart_intr_enable & INTR_STATE_TX_WATERMARK) { + qemu_set_irq(s->tx_watermark, 1); + } else { + qemu_set_irq(s->tx_watermark, 0); + } + + if (s->uart_intr_state & s->uart_intr_enable & INTR_STATE_RX_WATERMARK) { + qemu_set_irq(s->rx_watermark, 1); + } else { + qemu_set_irq(s->rx_watermark, 0); + } + + if (s->uart_intr_state & s->uart_intr_enable & INTR_STATE_TX_EMPTY) { + qemu_set_irq(s->tx_empty, 1); + } else { + qemu_set_irq(s->tx_empty, 0); + } + + if (s->uart_intr_state & s->uart_intr_enable & INTR_STATE_RX_OVERFLOW) { + qemu_set_irq(s->rx_overflow, 1); + } else { + qemu_set_irq(s->rx_overflow, 0); + } +} + +static int ibex_uart_can_receive(void *opaque) +{ + IbexUartState *s = opaque; + + if (s->uart_ctrl & UART_CTRL_RX_ENABLE) { + return 1; + } + + return 0; +} + +static void ibex_uart_receive(void *opaque, const uint8_t *buf, int size) +{ + IbexUartState *s = opaque; + uint8_t rx_fifo_level = (s->uart_fifo_ctrl & FIFO_CTRL_RXILVL) + >> FIFO_CTRL_RXILVL_SHIFT; + + s->uart_rdata = *buf; + + s->uart_status &= ~UART_STATUS_RXIDLE; + s->uart_status &= ~UART_STATUS_RXEMPTY; + + if (size > rx_fifo_level) { + s->uart_intr_state |= INTR_STATE_RX_WATERMARK; + } + + ibex_uart_update_irqs(s); +} + +static gboolean ibex_uart_xmit(GIOChannel *chan, GIOCondition cond, + void *opaque) +{ + IbexUartState *s = opaque; + uint8_t tx_fifo_level = (s->uart_fifo_ctrl & FIFO_CTRL_TXILVL) + >> FIFO_CTRL_TXILVL_SHIFT; + int ret; + + /* instant drain the fifo when there's no back-end */ + if (!qemu_chr_fe_backend_connected(&s->chr)) { + s->tx_level = 0; + return FALSE; + } + + if (!s->tx_level) { + s->uart_status &= ~UART_STATUS_TXFULL; + s->uart_status |= UART_STATUS_TXEMPTY; + s->uart_intr_state |= INTR_STATE_TX_EMPTY; + s->uart_intr_state &= ~INTR_STATE_TX_WATERMARK; + ibex_uart_update_irqs(s); + return FALSE; + } + + ret = qemu_chr_fe_write(&s->chr, s->tx_fifo, s->tx_level); + + if (ret >= 0) { + s->tx_level -= ret; + memmove(s->tx_fifo, s->tx_fifo + ret, s->tx_level); + } + + if (s->tx_level) { + guint r = qemu_chr_fe_add_watch(&s->chr, G_IO_OUT | G_IO_HUP, + ibex_uart_xmit, s); + if (!r) { + s->tx_level = 0; + return FALSE; + } + } + + /* Clear the TX Full bit */ + if (s->tx_level != IBEX_UART_TX_FIFO_SIZE) { + s->uart_status &= ~UART_STATUS_TXFULL; + } + + /* Disable the TX_WATERMARK IRQ */ + if (s->tx_level < tx_fifo_level) { + s->uart_intr_state &= ~INTR_STATE_TX_WATERMARK; + } + + /* Set TX empty */ + if (s->tx_level == 0) { + s->uart_status |= UART_STATUS_TXEMPTY; + s->uart_intr_state |= INTR_STATE_TX_EMPTY; + } + + ibex_uart_update_irqs(s); + return FALSE; +} + +static void uart_write_tx_fifo(IbexUartState *s, const uint8_t *buf, + int size) +{ + uint64_t current_time = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); + uint8_t tx_fifo_level = (s->uart_fifo_ctrl & FIFO_CTRL_TXILVL) + >> FIFO_CTRL_TXILVL_SHIFT; + + if (size > IBEX_UART_TX_FIFO_SIZE - s->tx_level) { + size = IBEX_UART_TX_FIFO_SIZE - s->tx_level; + qemu_log_mask(LOG_GUEST_ERROR, "ibex_uart: TX FIFO overflow"); + } + + memcpy(s->tx_fifo + s->tx_level, buf, size); + s->tx_level += size; + + if (s->tx_level > 0) { + s->uart_status &= ~UART_STATUS_TXEMPTY; + } + + if (s->tx_level >= tx_fifo_level) { + s->uart_intr_state |= INTR_STATE_TX_WATERMARK; + ibex_uart_update_irqs(s); + } + + if (s->tx_level == IBEX_UART_TX_FIFO_SIZE) { + s->uart_status |= UART_STATUS_TXFULL; + } + + timer_mod(s->fifo_trigger_handle, current_time + + (s->char_tx_time * 4)); +} + +static void ibex_uart_reset(DeviceState *dev) +{ + IbexUartState *s = IBEX_UART(dev); + + s->uart_intr_state = 0x00000000; + s->uart_intr_state = 0x00000000; + s->uart_intr_enable = 0x00000000; + s->uart_ctrl = 0x00000000; + s->uart_status = 0x0000003c; + s->uart_rdata = 0x00000000; + s->uart_fifo_ctrl = 0x00000000; + s->uart_fifo_status = 0x00000000; + s->uart_ovrd = 0x00000000; + s->uart_val = 0x00000000; + s->uart_timeout_ctrl = 0x00000000; + + s->tx_level = 0; + + s->char_tx_time = (NANOSECONDS_PER_SECOND / 230400) * 10; + + ibex_uart_update_irqs(s); +} + +static uint64_t ibex_uart_read(void *opaque, hwaddr addr, + unsigned int size) +{ + IbexUartState *s = opaque; + uint64_t retvalue = 0; + + switch (addr) { + case IBEX_UART_INTR_STATE: + retvalue = s->uart_intr_state; + break; + case IBEX_UART_INTR_ENABLE: + retvalue = s->uart_intr_enable; + break; + case IBEX_UART_INTR_TEST: + qemu_log_mask(LOG_GUEST_ERROR, + "%s: wdata is write only\n", __func__); + break; + + case IBEX_UART_CTRL: + retvalue = s->uart_ctrl; + break; + case IBEX_UART_STATUS: + retvalue = s->uart_status; + break; + + case IBEX_UART_RDATA: + retvalue = s->uart_rdata; + if (s->uart_ctrl & UART_CTRL_RX_ENABLE) { + qemu_chr_fe_accept_input(&s->chr); + + s->uart_status |= UART_STATUS_RXIDLE; + s->uart_status |= UART_STATUS_RXEMPTY; + } + break; + case IBEX_UART_WDATA: + qemu_log_mask(LOG_GUEST_ERROR, + "%s: wdata is write only\n", __func__); + break; + + case IBEX_UART_FIFO_CTRL: + retvalue = s->uart_fifo_ctrl; + break; + case IBEX_UART_FIFO_STATUS: + retvalue = s->uart_fifo_status; + + retvalue |= s->tx_level & 0x1F; + + qemu_log_mask(LOG_UNIMP, + "%s: RX fifos are not supported\n", __func__); + break; + + case IBEX_UART_OVRD: + retvalue = s->uart_ovrd; + qemu_log_mask(LOG_UNIMP, + "%s: ovrd is not supported\n", __func__); + break; + case IBEX_UART_VAL: + retvalue = s->uart_val; + qemu_log_mask(LOG_UNIMP, + "%s: val is not supported\n", __func__); + break; + case IBEX_UART_TIMEOUT_CTRL: + retvalue = s->uart_timeout_ctrl; + qemu_log_mask(LOG_UNIMP, + "%s: timeout_ctrl is not supported\n", __func__); + break; + default: + qemu_log_mask(LOG_GUEST_ERROR, + "%s: Bad offset 0x%"HWADDR_PRIx"\n", __func__, addr); + return 0; + } + + return retvalue; +} + +static void ibex_uart_write(void *opaque, hwaddr addr, + uint64_t val64, unsigned int size) +{ + IbexUartState *s = opaque; + uint32_t value = val64; + + switch (addr) { + case IBEX_UART_INTR_STATE: + /* Write 1 clear */ + s->uart_intr_state &= ~value; + ibex_uart_update_irqs(s); + break; + case IBEX_UART_INTR_ENABLE: + s->uart_intr_enable = value; + ibex_uart_update_irqs(s); + break; + case IBEX_UART_INTR_TEST: + s->uart_intr_state |= value; + ibex_uart_update_irqs(s); + break; + + case IBEX_UART_CTRL: + s->uart_ctrl = value; + + if (value & UART_CTRL_NF) { + qemu_log_mask(LOG_UNIMP, + "%s: UART_CTRL_NF is not supported\n", __func__); + } + if (value & UART_CTRL_SLPBK) { + qemu_log_mask(LOG_UNIMP, + "%s: UART_CTRL_SLPBK is not supported\n", __func__); + } + if (value & UART_CTRL_LLPBK) { + qemu_log_mask(LOG_UNIMP, + "%s: UART_CTRL_LLPBK is not supported\n", __func__); + } + if (value & UART_CTRL_PARITY_EN) { + qemu_log_mask(LOG_UNIMP, + "%s: UART_CTRL_PARITY_EN is not supported\n", + __func__); + } + if (value & UART_CTRL_PARITY_ODD) { + qemu_log_mask(LOG_UNIMP, + "%s: UART_CTRL_PARITY_ODD is not supported\n", + __func__); + } + if (value & UART_CTRL_RXBLVL) { + qemu_log_mask(LOG_UNIMP, + "%s: UART_CTRL_RXBLVL is not supported\n", __func__); + } + if (value & UART_CTRL_NCO) { + uint64_t baud = ((value & UART_CTRL_NCO) >> 16); + baud *= 1000; + baud /= 2 ^ 20; + + s->char_tx_time = (NANOSECONDS_PER_SECOND / baud) * 10; + } + break; + case IBEX_UART_STATUS: + qemu_log_mask(LOG_GUEST_ERROR, + "%s: status is read only\n", __func__); + break; + + case IBEX_UART_RDATA: + qemu_log_mask(LOG_GUEST_ERROR, + "%s: rdata is read only\n", __func__); + break; + case IBEX_UART_WDATA: + uart_write_tx_fifo(s, (uint8_t *) &value, 1); + break; + + case IBEX_UART_FIFO_CTRL: + s->uart_fifo_ctrl = value; + + if (value & FIFO_CTRL_RXRST) { + qemu_log_mask(LOG_UNIMP, + "%s: RX fifos are not supported\n", __func__); + } + if (value & FIFO_CTRL_TXRST) { + s->tx_level = 0; + } + break; + case IBEX_UART_FIFO_STATUS: + qemu_log_mask(LOG_GUEST_ERROR, + "%s: fifo_status is read only\n", __func__); + break; + + case IBEX_UART_OVRD: + s->uart_ovrd = value; + qemu_log_mask(LOG_UNIMP, + "%s: ovrd is not supported\n", __func__); + break; + case IBEX_UART_VAL: + qemu_log_mask(LOG_GUEST_ERROR, + "%s: val is read only\n", __func__); + break; + case IBEX_UART_TIMEOUT_CTRL: + s->uart_timeout_ctrl = value; + qemu_log_mask(LOG_UNIMP, + "%s: timeout_ctrl is not supported\n", __func__); + break; + default: + qemu_log_mask(LOG_GUEST_ERROR, + "%s: Bad offset 0x%"HWADDR_PRIx"\n", __func__, addr); + } +} + +static void fifo_trigger_update(void *opaque) +{ + IbexUartState *s = opaque; + + if (s->uart_ctrl & UART_CTRL_TX_ENABLE) { + ibex_uart_xmit(NULL, G_IO_OUT, s); + } +} + +static const MemoryRegionOps ibex_uart_ops = { + .read = ibex_uart_read, + .write = ibex_uart_write, + .endianness = DEVICE_NATIVE_ENDIAN, + .impl.min_access_size = 4, + .impl.max_access_size = 4, +}; + +static int ibex_uart_post_load(void *opaque, int version_id) +{ + IbexUartState *s = opaque; + + ibex_uart_update_irqs(s); + return 0; +} + +static const VMStateDescription vmstate_ibex_uart = { + .name = TYPE_IBEX_UART, + .version_id = 1, + .minimum_version_id = 1, + .post_load = ibex_uart_post_load, + .fields = (VMStateField[]) { + VMSTATE_UINT8_ARRAY(tx_fifo, IbexUartState, + IBEX_UART_TX_FIFO_SIZE), + VMSTATE_UINT32(tx_level, IbexUartState), + VMSTATE_UINT64(char_tx_time, IbexUartState), + VMSTATE_TIMER_PTR(fifo_trigger_handle, IbexUartState), + VMSTATE_UINT32(uart_intr_state, IbexUartState), + VMSTATE_UINT32(uart_intr_enable, IbexUartState), + VMSTATE_UINT32(uart_ctrl, IbexUartState), + VMSTATE_UINT32(uart_status, IbexUartState), + VMSTATE_UINT32(uart_rdata, IbexUartState), + VMSTATE_UINT32(uart_fifo_ctrl, IbexUartState), + VMSTATE_UINT32(uart_fifo_status, IbexUartState), + VMSTATE_UINT32(uart_ovrd, IbexUartState), + VMSTATE_UINT32(uart_val, IbexUartState), + VMSTATE_UINT32(uart_timeout_ctrl, IbexUartState), + VMSTATE_END_OF_LIST() + } +}; + +static Property ibex_uart_properties[] = { + DEFINE_PROP_CHR("chardev", IbexUartState, chr), + DEFINE_PROP_END_OF_LIST(), +}; + +static void ibex_uart_init(Object *obj) +{ + IbexUartState *s = IBEX_UART(obj); + + sysbus_init_irq(SYS_BUS_DEVICE(obj), &s->tx_watermark); + sysbus_init_irq(SYS_BUS_DEVICE(obj), &s->rx_watermark); + sysbus_init_irq(SYS_BUS_DEVICE(obj), &s->tx_empty); + sysbus_init_irq(SYS_BUS_DEVICE(obj), &s->rx_overflow); + + memory_region_init_io(&s->mmio, obj, &ibex_uart_ops, s, + TYPE_IBEX_UART, 0x400); + sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->mmio); +} + +static void ibex_uart_realize(DeviceState *dev, Error **errp) +{ + IbexUartState *s = IBEX_UART(dev); + + s->fifo_trigger_handle = timer_new_ns(QEMU_CLOCK_VIRTUAL, + fifo_trigger_update, s); + + qemu_chr_fe_set_handlers(&s->chr, ibex_uart_can_receive, + ibex_uart_receive, NULL, NULL, + s, NULL, true); +} + +static void ibex_uart_class_init(ObjectClass *klass, void *data) +{ + DeviceClass *dc = DEVICE_CLASS(klass); + + dc->reset = ibex_uart_reset; + dc->realize = ibex_uart_realize; + dc->vmsd = &vmstate_ibex_uart; + device_class_set_props(dc, ibex_uart_properties); +} + +static const TypeInfo ibex_uart_info = { + .name = TYPE_IBEX_UART, + .parent = TYPE_SYS_BUS_DEVICE, + .instance_size = sizeof(IbexUartState), + .instance_init = ibex_uart_init, + .class_init = ibex_uart_class_init, +}; + +static void ibex_uart_register_types(void) +{ + type_register_static(&ibex_uart_info); +} + +type_init(ibex_uart_register_types) |