virtio: rng: Add a random number generator(rng) driver

Add a driver for the virtio-rng device on the qemu platform. The
device uses pci as a transport medium. The driver can be enabled with
the following configs

CONFIG_VIRTIO
CONFIG_DM_RNG
CONFIG_VIRTIO_PCI
CONFIG_VIRTIO_RNG

Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>

diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
index a9d5fd07b775db571cb2586267182054642d671c..2e3dd3bad0735cbd894aa1aa3a61b368d173cc95 100644 (file)
--- a/drivers/virtio/Kconfig
+++ b/drivers/virtio/Kconfig
@@ -59,4 +59,10 @@ config VIRTIO_BLK
          This is the virtual block driver for virtio. It can be used with
          QEMU based targets.
 
+config VIRTIO_RNG
+       bool "virtio rng driver"
+       depends on VIRTIO
+       help
+         This is the virtual random number generator driver. It can be used
+        with Qemu based targets.
 endmenu

diff --git a/drivers/virtio/Makefile b/drivers/virtio/Makefile
index 4579044ae39fd1133a53a9c3b515ef1d976af5a2..dc8880937a84710cf359984f87c0b0acb26d0dd3 100644 (file)
--- a/drivers/virtio/Makefile
+++ b/drivers/virtio/Makefile
@@ -9,3 +9,4 @@ obj-$(CONFIG_VIRTIO_PCI) += virtio_pci_legacy.o virtio_pci_modern.o
 obj-$(CONFIG_VIRTIO_SANDBOX) += virtio_sandbox.o
 obj-$(CONFIG_VIRTIO_NET) += virtio_net.o
 obj-$(CONFIG_VIRTIO_BLK) += virtio_blk.o
+obj-$(CONFIG_VIRTIO_RNG) += virtio_rng.o

diff --git a/drivers/virtio/virtio-uclass.c b/drivers/virtio/virtio-uclass.c
index 34397d7dbb11f7fde56f4a224b221061cdb6eca7..436faa46eecffafffa67f7a22153c2d9c761cf42 100644 (file)
--- a/drivers/virtio/virtio-uclass.c
+++ b/drivers/virtio/virtio-uclass.c
@@ -24,6 +24,7 @@
 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_RNG]         = VIRTIO_RNG_DRV_NAME,
 };
 
 int virtio_get_config(struct udevice *vdev, unsigned int offset,

diff --git a/drivers/virtio/virtio_rng.c b/drivers/virtio/virtio_rng.c
new file mode 100644 (file)
index 0000000..4edffa6
--- /dev/null
+++ b/drivers/virtio/virtio_rng.c
@@ -0,0 +1,88 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2019, Linaro Limited
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <rng.h>
+#include <virtio_types.h>
+#include <virtio.h>
+#include <virtio_ring.h>
+
+#define BUFFER_SIZE    16UL
+
+struct virtio_rng_priv {
+       struct virtqueue *rng_vq;
+};
+
+static int virtio_rng_read(struct udevice *dev, void *data, size_t len)
+{
+       int ret;
+       unsigned int rsize;
+       unsigned char buf[BUFFER_SIZE] __aligned(4);
+       unsigned char *ptr = data;
+       struct virtio_sg sg;
+       struct virtio_sg *sgs[1];
+       struct virtio_rng_priv *priv = dev_get_priv(dev);
+
+       while (len) {
+               sg.addr = buf;
+               sg.length = min(len, sizeof(buf));
+               sgs[0] = &sg;
+
+               ret = virtqueue_add(priv->rng_vq, sgs, 0, 1);
+               if (ret)
+                       return ret;
+
+               virtqueue_kick(priv->rng_vq);
+
+               while (!virtqueue_get_buf(priv->rng_vq, &rsize))
+                       ;
+
+               memcpy(ptr, buf, rsize);
+               len -= rsize;
+               ptr += rsize;
+       }
+
+       return 0;
+}
+
+static int virtio_rng_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;
+}
+
+static int virtio_rng_probe(struct udevice *dev)
+{
+       struct virtio_rng_priv *priv = dev_get_priv(dev);
+       int ret;
+
+       ret = virtio_find_vqs(dev, 1, &priv->rng_vq);
+       if (ret < 0) {
+               debug("%s: virtio_find_vqs failed\n", __func__);
+               return ret;
+       }
+
+       return 0;
+}
+
+static const struct dm_rng_ops virtio_rng_ops = {
+       .read   = virtio_rng_read,
+};
+
+U_BOOT_DRIVER(virtio_rng) = {
+       .name   = VIRTIO_RNG_DRV_NAME,
+       .id     = UCLASS_RNG,
+       .bind   = virtio_rng_bind,
+       .probe  = virtio_rng_probe,
+       .remove = virtio_reset,
+       .ops    = &virtio_rng_ops,
+       .priv_auto_alloc_size = sizeof(struct virtio_rng_priv),
+       .flags  = DM_FLAG_ACTIVE_DMA,
+};

diff --git a/include/virtio.h b/include/virtio.h
index 654fdf154b6c9731daa35e303e3dc24a32eeb42a..561dcc34baf735783e21f793a54b06d20b89046d 100644 (file)
--- a/include/virtio.h
+++ b/include/virtio.h
@@ -22,10 +22,12 @@
 
 #define VIRTIO_ID_NET          1 /* virtio net */
 #define VIRTIO_ID_BLOCK                2 /* virtio block */
-#define VIRTIO_ID_MAX_NUM      3
+#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_RNG_DRV_NAME    "virtio-rng"
 
 /* Status byte for guest to report progress, and synchronize features */