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 --- Changes since V6: * Handle review comments from Heinrich Schuchardt to handle the scenario of data buffer being passed to the virtio rng driver not being aligned on 4 bytes.
drivers/virtio/Kconfig | 6 +++ drivers/virtio/Makefile | 1 + drivers/virtio/virtio-uclass.c | 1 + drivers/virtio/virtio_rng.c | 92 ++++++++++++++++++++++++++++++++++++++++++ include/virtio.h | 4 +- 5 files changed, 103 insertions(+), 1 deletion(-) create mode 100644 drivers/virtio/virtio_rng.c
diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig index a9d5fd0..2e3dd3b 100644 --- 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 4579044..dc88809 100644 --- 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 34397d7..436faa4 100644 --- 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 index 0000000..ffb6835 --- /dev/null +++ b/drivers/virtio/virtio_rng.c @@ -0,0 +1,92 @@ +// 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 = 0; + size_t nbytes = len; + 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); + + if (!len) + return 0; + + do { + sg.addr = buf; + sg.length = nbytes; + 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); + nbytes -= rsize; + ptr += rsize; + } while (nbytes != 0); + + 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 654fdf1..561dcc3 100644 --- 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 */