On Wed, 3 Jan 2018 13:44:21 +1300
Michael Clark <m...@sifive.com> wrote:
> QEMU model of the UART on the SiFive E300 and U500 series SOCs.
> BBL supports the SiFive UART for early console access via the SBI
> (Supervisor Binary Interface) and the linux kernel SBI console.
>
> The SiFive UART implements the pre qom legacy interface consistent
> with the 16550a UART in 'hw/char/serial.c'.
>
> Signed-off-by: Michael Clark <m...@sifive.com>
> ---
> hw/riscv/sifive_uart.c | 182
> +++++++++++++++++++++++++++++++++++++++++
> include/hw/riscv/sifive_uart.h | 76 +++++++++++++++++
> 2 files changed, 258 insertions(+)
> create mode 100644 hw/riscv/sifive_uart.c
> create mode 100644 include/hw/riscv/sifive_uart.h
>
> diff --git a/hw/riscv/sifive_uart.c b/hw/riscv/sifive_uart.c
> new file mode 100644
> index 0000000..0e73df6
> --- /dev/null
> +++ b/hw/riscv/sifive_uart.c
> @@ -0,0 +1,182 @@
> +/*
> + * QEMU model of the UART on the SiFive E300 and U500 series SOCs.
> + *
> + * Copyright (c) 2016 Stefan O'Rear
> + *
> + * 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 "qapi/error.h"
> +#include "hw/sysbus.h"
> +#include "chardev/char.h"
> +#include "chardev/char-fe.h"
> +#include "target/riscv/cpu.h"
> +#include "hw/riscv/sifive_uart.h"
> +
> +/*
> + * Not yet implemented:
> + *
> + * Transmit FIFO using "qemu/fifo8.h"
> + * SIFIVE_UART_IE_TXWM interrupts
> + * SIFIVE_UART_IE_RXWM interrupts must honor fifo watermark
> + * Rx FIFO watermark interrupt trigger threshold
> + * Tx FIFO watermark interrupt trigger threshold.
> + */
> +
> +static void update_irq(SiFiveUARTState *s)
> +{
> + int cond = 0;
> + if ((s->ie & SIFIVE_UART_IE_RXWM) && s->rx_fifo_len) {
> + cond = 1;
> + }
> + if (cond) {
> + qemu_irq_raise(s->irq);
> + } else {
> + qemu_irq_lower(s->irq);
> + }
> +}
> +
> +static uint64_t
> +uart_read(void *opaque, hwaddr addr, unsigned int size)
> +{
> + SiFiveUARTState *s = opaque;
> + unsigned char r;
> + switch (addr) {
> + case SIFIVE_UART_RXFIFO:
> + if (s->rx_fifo_len) {
> + r = s->rx_fifo[0];
> + memmove(s->rx_fifo, s->rx_fifo + 1, s->rx_fifo_len - 1);
> + s->rx_fifo_len--;
qemu already has code for FIFO implementation.
Can we use Fifo8 as hw/char/serial.c does?
Please see my 'hw/sifive_uart: use generic Fifo8' patch:
https://github.com/riscv/riscv-qemu/pull/60/commits/6d68a4bc9a617b72ec563f72e58e2467998d5c4b
> + qemu_chr_fe_accept_input(&s->chr);
> + update_irq(s);
> + return r;
> + }
> + return 0x80000000;
> +
> + case SIFIVE_UART_TXFIFO:
> + return 0; /* Should check tx fifo */
> + case SIFIVE_UART_IE:
> + return s->ie;
> + case SIFIVE_UART_IP:
> + return s->rx_fifo_len ? SIFIVE_UART_IP_RXWM : 0;
> + case SIFIVE_UART_TXCTRL:
> + return s->txctrl;
> + case SIFIVE_UART_RXCTRL:
> + return s->rxctrl;
> + case SIFIVE_UART_DIV:
> + return s->div;
> + }
> +
> + hw_error("%s: bad read: addr=0x%x\n",
> + __func__, (int)addr);
> + return 0;
> +}
> +
> +static void
> +uart_write(void *opaque, hwaddr addr,
> + uint64_t val64, unsigned int size)
> +{
> + SiFiveUARTState *s = opaque;
> + uint32_t value = val64;
> + unsigned char ch = value;
> +
> + switch (addr) {
> + case SIFIVE_UART_TXFIFO:
> + qemu_chr_fe_write(&s->chr, &ch, 1);
> + return;
> + case SIFIVE_UART_IE:
> + s->ie = val64;
> + update_irq(s);
> + return;
> + case SIFIVE_UART_TXCTRL:
> + s->txctrl = val64;
> + return;
> + case SIFIVE_UART_RXCTRL:
> + s->rxctrl = val64;
> + return;
> + case SIFIVE_UART_DIV:
> + s->div = val64;
> + return;
> + }
> + hw_error("%s: bad write: addr=0x%x v=0x%x\n",
> + __func__, (int)addr, (int)value);
> +}
> +
> +static const MemoryRegionOps uart_ops = {
> + .read = uart_read,
> + .write = uart_write,
> + .endianness = DEVICE_NATIVE_ENDIAN,
> + .valid = {
> + .min_access_size = 4,
> + .max_access_size = 4
> + }
> +};
> +
> +static void uart_rx(void *opaque, const uint8_t *buf, int size)
> +{
> + SiFiveUARTState *s = opaque;
> +
> + /* Got a byte. */
> + if (s->rx_fifo_len >= sizeof(s->rx_fifo)) {
> + printf("WARNING: UART dropped char.\n");
> + return;
> + }
> + s->rx_fifo[s->rx_fifo_len++] = *buf;
> +
> + update_irq(s);
> +}
> +
> +static int uart_can_rx(void *opaque)
> +{
> + SiFiveUARTState *s = opaque;
> +
> + return s->rx_fifo_len < sizeof(s->rx_fifo);
> +}
> +
> +static void uart_event(void *opaque, int event)
> +{
> +}
> +
> +static int uart_be_change(void *opaque)
> +{
> + SiFiveUARTState *s = opaque;
> +
> + qemu_chr_fe_set_handlers(&s->chr, uart_can_rx, uart_rx, uart_event,
> + uart_be_change, s, NULL, true);
> +
> + return 0;
> +}
> +
> +/*
> + * Create UART device.
> + */
> +SiFiveUARTState *sifive_uart_create(MemoryRegion *address_space, hwaddr base,
> + Chardev *chr, qemu_irq irq)
> +{
> + SiFiveUARTState *s = g_malloc0(sizeof(SiFiveUARTState));
> + s->irq = irq;
> + qemu_chr_fe_init(&s->chr, chr, &error_abort);
> + qemu_chr_fe_set_handlers(&s->chr, uart_can_rx, uart_rx, uart_event,
> + uart_be_change, s, NULL, true);
> + memory_region_init_io(&s->mmio, NULL, &uart_ops, s,
> + TYPE_SIFIVE_UART, SIFIVE_UART_MAX);
> + memory_region_add_subregion(address_space, base, &s->mmio);
> + return s;
> +}
> diff --git a/include/hw/riscv/sifive_uart.h b/include/hw/riscv/sifive_uart.h
> new file mode 100644
> index 0000000..1ab0106
> --- /dev/null
> +++ b/include/hw/riscv/sifive_uart.h
> @@ -0,0 +1,76 @@
> +/*
> + * SiFive UART interface
> + *
> + * Copyright (c) 2017 SiFive, Inc.
> + *
> + * 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.
> + */
> +
> +#ifndef HW_SIFIVE_UART_H
> +#define HW_SIFIVE_UART_H
> +
> +enum {
> + SIFIVE_UART_TXFIFO = 0,
> + SIFIVE_UART_RXFIFO = 4,
> + SIFIVE_UART_TXCTRL = 8,
> + SIFIVE_UART_TXMARK = 10,
> + SIFIVE_UART_RXCTRL = 12,
> + SIFIVE_UART_RXMARK = 14,
> + SIFIVE_UART_IE = 16,
> + SIFIVE_UART_IP = 20,
> + SIFIVE_UART_DIV = 24,
> + SIFIVE_UART_MAX = 32
> +};
> +
> +enum {
> + SIFIVE_UART_IE_TXWM = 1, /* Transmit watermark interrupt enable */
> + SIFIVE_UART_IE_RXWM = 2 /* Receive watermark interrupt enable */
> +};
> +
> +enum {
> + SIFIVE_UART_IP_TXWM = 1, /* Transmit watermark interrupt pending */
> + SIFIVE_UART_IP_RXWM = 2 /* Receive watermark interrupt pending */
> +};
> +
> +#define TYPE_SIFIVE_UART "riscv.sifive.uart"
> +
> +#define SIFIVE_UART(obj) \
> + OBJECT_CHECK(SiFiveUARTState, (obj), TYPE_SIFIVE_UART)
> +
> +typedef struct SiFiveUARTState {
> + /*< private >*/
> + SysBusDevice parent_obj;
> +
> + /*< public >*/
> + qemu_irq irq;
> + MemoryRegion mmio;
> + CharBackend chr;
> + uint8_t rx_fifo[8];
> + unsigned int rx_fifo_len;
> + uint32_t ie;
> + uint32_t ip;
> + uint32_t txctrl;
> + uint32_t rxctrl;
> + uint32_t div;
> +} SiFiveUARTState;
> +
> +SiFiveUARTState *sifive_uart_create(MemoryRegion *address_space, hwaddr base,
> + Chardev *chr, qemu_irq irq);
> +
> +#endif
> --
> 2.7.0
>
>
--
Best regards,
Antony Pavlov
