SiFive RISC-V UART Device

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'.

Acked-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Stefan O'Rear <sorear2@gmail.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: Michael Clark <mjc@sifive.com>

1 files changed, 71 insertions, 0 deletions

diff --git a/include/hw/riscv/sifive_uart.h b/include/hw/riscv/sifive_uart.h
new file mode 100644
index 0000000000..504f18a60f
--- /dev/null
+++ b/include/hw/riscv/sifive_uart.h
@@ -0,0 +1,71 @@
+/*
+ * SiFive UART interface
+ *
+ * Copyright (c) 2016 Stefan O'Rear
+ * Copyright (c) 2017 SiFive, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2 or later, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#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