[PATCH 1/1] virtio: add driver for virtio_console devices
Ying-Chun Liu (PaulLiu)
paulliu at debian.org
Tue Jun 6 15:25:40 CEST 2023
From: "A. Cody Schuffelen" <schuffelen at google.com>
This is an implementation of single-character virtio-console. Part of the
patch is based on barebox implementations.
Signed-off-by: A. Cody Schuffelen <schuffelen at google.com>
[ Paul: pick from the Android tree. Rebase to the upstream. Small fixes. ]
Signed-off-by: Ying-Chun Liu (PaulLiu) <paul.liu at linaro.org>
Link: https://android.googlesource.com/platform/external/u-boot/+/bc68da98ebf835a50d869cf01c535ac936bfcb11
Link: https://git.pengutronix.de/cgit/barebox/tree/drivers/serial/virtio_console.c?id=180a551d542844b70012d7b94a415aacdcf31d45
Link: https://android.googlesource.com/platform/external/u-boot/+/4581f7c6e96d7332b534ae20de356a4554594d08
Cc: Bin Meng <bmeng.cn at gmail.com>
---
drivers/virtio/Kconfig | 8 ++
drivers/virtio/Makefile | 1 +
drivers/virtio/virtio-uclass.c | 1 +
drivers/virtio/virtio_console.c | 158 ++++++++++++++++++++++++++++++++
include/virtio.h | 2 +
5 files changed, 170 insertions(+)
create mode 100644 drivers/virtio/virtio_console.c
diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
index 852f6735b6..94aaf70ab9 100644
--- a/drivers/virtio/Kconfig
+++ b/drivers/virtio/Kconfig
@@ -68,6 +68,14 @@ config VIRTIO_BLK
This is the virtual block driver for virtio. It can be used with
QEMU based targets.
+config VIRTIO_CONSOLE
+ bool "virtio console driver"
+ depends on VIRTIO
+ default y
+ help
+ This is the virtual console driver for virtio. It can be used
+ with QEMU based targets.
+
config VIRTIO_RNG
bool "virtio rng driver"
depends on DM_RNG
diff --git a/drivers/virtio/Makefile b/drivers/virtio/Makefile
index 4c63a6c690..c816f66aa6 100644
--- a/drivers/virtio/Makefile
+++ b/drivers/virtio/Makefile
@@ -10,4 +10,5 @@ obj-$(CONFIG_VIRTIO_PCI_LEGACY) += virtio_pci_legacy.o
obj-$(CONFIG_VIRTIO_SANDBOX) += virtio_sandbox.o
obj-$(CONFIG_VIRTIO_NET) += virtio_net.o
obj-$(CONFIG_VIRTIO_BLK) += virtio_blk.o
+obj-$(CONFIG_VIRTIO_CONSOLE) += virtio_console.o
obj-$(CONFIG_VIRTIO_RNG) += virtio_rng.o
diff --git a/drivers/virtio/virtio-uclass.c b/drivers/virtio/virtio-uclass.c
index 31bb21c534..9c54c67572 100644
--- a/drivers/virtio/virtio-uclass.c
+++ b/drivers/virtio/virtio-uclass.c
@@ -30,6 +30,7 @@
static const char *const virtio_drv_name[VIRTIO_ID_MAX_NUM] = {
[VIRTIO_ID_NET] = VIRTIO_NET_DRV_NAME,
[VIRTIO_ID_BLOCK] = VIRTIO_BLK_DRV_NAME,
+ [VIRTIO_ID_CONSOLE] = VIRTIO_CONSOLE_DRV_NAME,
[VIRTIO_ID_RNG] = VIRTIO_RNG_DRV_NAME,
};
diff --git a/drivers/virtio/virtio_console.c b/drivers/virtio/virtio_console.c
new file mode 100644
index 0000000000..1d4b319b08
--- /dev/null
+++ b/drivers/virtio/virtio_console.c
@@ -0,0 +1,158 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018, Tuomas Tynkkynen <tuomas.tynkkynen at iki.fi>
+ * Copyright (C) 2018, Bin Meng <bmeng.cn at gmail.com>
+ * Copyright (C) 2006, 2007, 2009 Rusty Russell, IBM Corporation
+ * Copyright (C) 2009, 2010, 2011 Red Hat, Inc.
+ * Copyright (C) 2009, 2010, 2011 Amit Shah <amit.shah at redhat.com>
+ * Copyright (C) 2021 Ahmad Fatoum
+ * Copyright (C) 2021, Google LLC, schuffelen at google.com (A. Cody Schuffelen)
+ * Copyright (C) 2023, Linaro
+ */
+
+#include <common.h>
+#include <blk.h>
+#include <dm.h>
+#include <part.h>
+#include <serial.h>
+#include <virtio_types.h>
+#include <virtio.h>
+#include <virtio_ring.h>
+#include "virtio_blk.h"
+
+struct virtio_console_priv {
+ struct virtqueue *receiveq_port0;
+ struct virtqueue *transmitq_port0;
+ unsigned char inbuf[1] __aligned(4);
+};
+
+static int virtio_console_bind(struct udevice *dev)
+{
+ struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(dev->parent);
+
+ /* Indicate what driver features we support */
+ virtio_driver_features_init(uc_priv, NULL, 0, NULL, 0);
+
+ return 0;
+}
+
+/*
+ * Create a scatter-gather list representing our input buffer and put
+ * it in the queue.
+ */
+static void add_inbuf(struct virtio_console_priv *priv)
+{
+ struct virtio_sg sg;
+ struct virtio_sg *sgs[1];
+ int ret;
+
+ sgs[0] = &sg;
+ sg.addr = priv->inbuf;
+ sg.length = sizeof(priv->inbuf);
+
+ ret = virtqueue_add(priv->receiveq_port0, sgs, 0, 1);
+ /* We should always be able to add one buffer to an empty queue. */
+ WARN(ret < 0, "%s: virtqueue_add failed\n", __func__);
+
+ virtqueue_kick(priv->receiveq_port0);
+}
+
+static int virtio_console_probe(struct udevice *dev)
+{
+ struct virtio_console_priv *priv = dev_get_priv(dev);
+ int ret;
+
+ struct virtqueue *virtqueues[2];
+
+ ret = virtio_find_vqs(dev, 2, virtqueues);
+ if (ret < 0) {
+ debug("%s: virtio_find_vqs failed\n", __func__);
+ return ret;
+ }
+
+ priv->receiveq_port0 = virtqueues[0];
+ priv->transmitq_port0 = virtqueues[1];
+
+ /* Register the input buffer the first time. */
+ add_inbuf(priv);
+
+ return 0;
+}
+
+static int virtio_console_serial_setbrg(struct udevice *dev, int baudrate)
+{
+ return 0;
+}
+
+static int virtio_console_serial_pending(struct udevice *dev, bool input)
+{
+ struct virtio_console_priv *priv = dev_get_priv(dev);
+
+ return virtqueue_poll(priv->receiveq_port0,
+ priv->receiveq_port0->last_used_idx);
+}
+
+static int virtio_console_serial_getc(struct udevice *dev)
+{
+ struct virtio_console_priv *priv = dev_get_priv(dev);
+ unsigned char *in;
+ int ch;
+ unsigned int len = 0;
+
+ in = virtqueue_get_buf(priv->receiveq_port0, &len);
+ if (!in)
+ return -EAGAIN;
+
+ WARN(len != 1, "%s: too much data: %d\n", __func__, len);
+
+ ch = *in;
+
+ add_inbuf(priv);
+
+ return ch;
+}
+
+static int virtio_console_serial_putc(struct udevice *dev, const char ch)
+{
+ struct virtio_console_priv *priv = dev_get_priv(dev);
+ struct virtio_sg sg;
+ struct virtio_sg *sgs[1];
+ unsigned char buf[1] __aligned(4);
+ int ret = 0;
+
+ sg.addr = buf;
+ sg.length = sizeof(buf);
+ sgs[0] = &sg;
+ buf[0] = ch;
+
+ ret = virtqueue_add(priv->transmitq_port0, sgs, 1, 0);
+ if (ret) {
+ debug("%s: virtqueue_add failed\n", __func__);
+ return ret;
+ }
+
+ virtqueue_kick(priv->transmitq_port0);
+
+ while (!virtqueue_get_buf(priv->transmitq_port0, NULL))
+ ;
+
+ return 0;
+}
+
+static const struct dm_serial_ops virtio_console_serial_ops = {
+ .putc = virtio_console_serial_putc,
+ .pending = virtio_console_serial_pending,
+ .getc = virtio_console_serial_getc,
+ .setbrg = virtio_console_serial_setbrg,
+};
+
+U_BOOT_DRIVER(virtio_console) = {
+ .name = VIRTIO_CONSOLE_DRV_NAME,
+ .id = UCLASS_SERIAL,
+ .ops = &virtio_console_serial_ops,
+ .bind = virtio_console_bind,
+ .probe = virtio_console_probe,
+ .remove = virtio_reset,
+ .priv_auto = sizeof(struct virtio_console_priv),
+ .flags = DM_FLAG_ACTIVE_DMA,
+};
diff --git a/include/virtio.h b/include/virtio.h
index 062a24630c..e36dd41fd1 100644
--- a/include/virtio.h
+++ b/include/virtio.h
@@ -25,11 +25,13 @@
#include <linux/bug.h>
#define VIRTIO_ID_NET 1 /* virtio net */
#define VIRTIO_ID_BLOCK 2 /* virtio block */
+#define VIRTIO_ID_CONSOLE 3 /* virtio console */
#define VIRTIO_ID_RNG 4 /* virtio rng */
#define VIRTIO_ID_MAX_NUM 5
#define VIRTIO_NET_DRV_NAME "virtio-net"
#define VIRTIO_BLK_DRV_NAME "virtio-blk"
+#define VIRTIO_CONSOLE_DRV_NAME "virtio-console"
#define VIRTIO_RNG_DRV_NAME "virtio-rng"
/* Status byte for guest to report progress, and synchronize features */
--
2.39.2
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