[PATCH 1/2] lib: utils/serial: add virtio mmio driver
Bohdan Fedorov
misterjdrg at gmail.com
Sun Jun 12 10:18:21 PDT 2022
Simple virtio-console driver.
Useful for running opensbi in virtualized environments.
dt-bindings:
<linux>/Documentation/devicetree/bindings/virtio/mmio.yaml
Signed-off-by: Bohdan Fedorov <misterjdrg at gmail.com>
---
include/sbi_utils/fdt/fdt_helper.h | 3 +
include/sbi_utils/serial/virtio-uart.h | 19 +++++++
lib/utils/fdt/fdt_helper.c | 18 ++++++
lib/utils/serial/fdt_serial_virtio.c | 37 +++++++++++++
lib/utils/serial/objects.mk | 4 ++
lib/utils/serial/virtio-uart.c | 76 ++++++++++++++++++++++++++
6 files changed, 157 insertions(+)
create mode 100644 include/sbi_utils/serial/virtio-uart.h
create mode 100644 lib/utils/serial/fdt_serial_virtio.c
create mode 100644 lib/utils/serial/virtio-uart.c
diff --git a/include/sbi_utils/fdt/fdt_helper.h b/include/sbi_utils/fdt/fdt_helper.h
index c60af35..80307bb 100644
--- a/include/sbi_utils/fdt/fdt_helper.h
+++ b/include/sbi_utils/fdt/fdt_helper.h
@@ -65,6 +65,9 @@ int fdt_parse_shakti_uart_node(void *fdt, int nodeoffset,
int fdt_parse_sifive_uart_node(void *fdt, int nodeoffset,
struct platform_uart_data *uart);
+int fdt_parse_virtio_uart_node(void *fdt, int nodeoffset,
+ struct platform_uart_data *uart);
+
int fdt_parse_uart8250_node(void *fdt, int nodeoffset,
struct platform_uart_data *uart);
diff --git a/include/sbi_utils/serial/virtio-uart.h b/include/sbi_utils/serial/virtio-uart.h
new file mode 100644
index 0000000..4fdfebc
--- /dev/null
+++ b/include/sbi_utils/serial/virtio-uart.h
@@ -0,0 +1,19 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2019 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ * Bohdan Fedorov <misterjdrg at gmail.com>
+ *
+ * Based on:
+ * sifive-uart
+ */
+
+#ifndef __SERIAL_SIFIVE_UART_H__
+#define __SERIAL_SIFIVE_UART_H__
+
+
+int virtio_uart_init(unsigned long base);
+
+#endif
diff --git a/lib/utils/fdt/fdt_helper.c b/lib/utils/fdt/fdt_helper.c
index 2bdb1ef..9bfd5e7 100644
--- a/lib/utils/fdt/fdt_helper.c
+++ b/lib/utils/fdt/fdt_helper.c
@@ -388,6 +388,24 @@ int fdt_parse_shakti_uart_node(void *fdt, int nodeoffset,
return 0;
}
+int fdt_parse_virtio_uart_node(void *fdt, int nodeoffset,
+ struct platform_uart_data *uart)
+{
+ int rc;
+ uint64_t reg_addr, reg_size;
+
+ if (nodeoffset < 0 || !uart || !fdt)
+ return SBI_ENODEV;
+
+ rc = fdt_get_node_addr_size(fdt, nodeoffset, 0,
+ ®_addr, ®_size);
+ if (rc < 0 || !reg_addr || !reg_size)
+ return SBI_ENODEV;
+ uart->addr = reg_addr;
+
+ return 0;
+}
+
int fdt_parse_sifive_uart_node(void *fdt, int nodeoffset,
struct platform_uart_data *uart)
{
diff --git a/lib/utils/serial/fdt_serial_virtio.c b/lib/utils/serial/fdt_serial_virtio.c
new file mode 100644
index 0000000..115c5ad
--- /dev/null
+++ b/lib/utils/serial/fdt_serial_virtio.c
@@ -0,0 +1,37 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2020 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ * Bohdan Fedorov <misterjdrg at gmail.com>
+ *
+ * Based on virtio-uart
+ */
+
+#include <sbi_utils/fdt/fdt_helper.h>
+#include <sbi_utils/serial/fdt_serial.h>
+#include <sbi_utils/serial/virtio-uart.h>
+
+static int serial_virtio_init(void *fdt, int nodeoff,
+ const struct fdt_match *match)
+{
+ int rc;
+ struct platform_uart_data uart;
+
+ rc = fdt_parse_virtio_uart_node(fdt, nodeoff, &uart);
+ if (rc)
+ return rc;
+
+ return virtio_uart_init(uart.addr);
+}
+
+static const struct fdt_match serial_virtio_match[] = {
+ { .compatible = "virtio,mmio" },
+ { },
+};
+
+struct fdt_serial fdt_serial_virtio = {
+ .match_table = serial_virtio_match,
+ .init = serial_virtio_init
+};
diff --git a/lib/utils/serial/objects.mk b/lib/utils/serial/objects.mk
index d26a74e..60e829b 100644
--- a/lib/utils/serial/objects.mk
+++ b/lib/utils/serial/objects.mk
@@ -22,6 +22,9 @@ libsbiutils-objs-y += serial/fdt_serial_shakti.o
carray-fdt_serial_drivers-y += fdt_serial_sifive
libsbiutils-objs-y += serial/fdt_serial_sifive.o
+carray-fdt_serial_drivers-y += fdt_serial_virtio
+libsbiutils-objs-y += serial/fdt_serial_virtio.o
+
carray-fdt_serial_drivers-y += fdt_serial_litex
libsbiutils-objs-y += serial/fdt_serial_litex.o
@@ -34,6 +37,7 @@ libsbiutils-objs-y += serial/fdt_serial_xlnx_uartlite.o
libsbiutils-objs-y += serial/gaisler-uart.o
libsbiutils-objs-y += serial/shakti-uart.o
libsbiutils-objs-y += serial/sifive-uart.o
+libsbiutils-objs-y += serial/virtio-uart.o
libsbiutils-objs-y += serial/litex-uart.o
libsbiutils-objs-y += serial/uart8250.o
libsbiutils-objs-y += serial/xlnx-uartlite.o
diff --git a/lib/utils/serial/virtio-uart.c b/lib/utils/serial/virtio-uart.c
new file mode 100644
index 0000000..1d4266f
--- /dev/null
+++ b/lib/utils/serial/virtio-uart.c
@@ -0,0 +1,76 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2019 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ * Bohdan Fedorov <misterjdrg at gmial.com>
+ *
+ * Based on:
+ * sifive-uart
+ */
+
+#include <sbi/riscv_io.h>
+#include <sbi/sbi_error.h>
+#include <sbi/sbi_console.h>
+#include <sbi_utils/serial/virtio-uart.h>
+
+/* clang-format off */
+
+#define VIRTIO_MAGIC 0x0
+#define VIRTIO_MAGIC_VALUE 0x74726976
+#define VIRTIO_DEVICE_ID 0x8
+#define VIRTIO_DEVICE_ID_CONSOLE 0x3
+#define VIRTIO_CONSOLE_F_EMERG_WRITE (1 << 2)
+#define VIRTIO_DEVICE_FEATURES 0x10
+#define VIRTIO_DEVICE_FEATURES_SEL 0x14
+#define VIRTIO_CONSOLE_EMERG_WR 0x108
+
+/* clang-format on */
+
+static volatile void *uart_base;
+
+static u32 get_reg(u32 off)
+{
+ return readl(uart_base + off);
+}
+
+static void set_reg(u32 off, u32 val)
+{
+ writel(val, uart_base + off);
+}
+
+static void virtio_uart_putc(char ch)
+{
+ set_reg(VIRTIO_CONSOLE_EMERG_WR, ch);
+}
+
+static struct sbi_console_device virtio_console = {
+ .name = "virtio_uart",
+ .console_putc = virtio_uart_putc,
+ .console_getc = NULL,
+};
+
+int virtio_uart_init(unsigned long base)
+{
+ uart_base = (volatile void *)base;
+
+ // Chech magic
+ if(get_reg(VIRTIO_MAGIC) != VIRTIO_MAGIC_VALUE) {
+ return SBI_ENODEV;
+ }
+
+ // Virtio device is console
+ if(get_reg(VIRTIO_DEVICE_ID) != VIRTIO_DEVICE_ID_CONSOLE) {
+ return SBI_ENODEV;
+ }
+
+ // Virtio console has emergency write feature
+ set_reg(VIRTIO_DEVICE_FEATURES_SEL, 0);
+ if((get_reg(VIRTIO_DEVICE_FEATURES) & VIRTIO_CONSOLE_F_EMERG_WRITE) == 0) {
+ return SBI_ENODEV;
+ }
+
+ sbi_console_set_device(&virtio_console);
+ return 0;
+}
--
2.36.1
More information about the opensbi
mailing list