dm: Add a new uclass driver for VirtIO transport devices
This adds a new virtio uclass driver for “virtio” [1] family of
devices that are are found in virtual environments like QEMU,
yet by design they look like physical devices to the guest.
The uclass driver provides child_pre_probe() and child_post_probe()
methods to do some common operations for virtio device drivers like
device and driver supported feature negotiation, etc.
[1] http://docs.oasis-open.org/virtio/virtio/v1.0/virtio-v1.0.pdf
Signed-off-by: Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/include/virtio.h b/include/virtio.h
new file mode 100644
index 0000000..654fdf1
--- /dev/null
+++ b/include/virtio.h
@@ -0,0 +1,707 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (C) 2018, Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
+ * Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+ *
+ * VirtIO is a virtualization standard for network and disk device drivers
+ * where just the guest's device driver "knows" it is running in a virtual
+ * environment, and cooperates with the hypervisor. This enables guests to
+ * get high performance network and disk operations, and gives most of the
+ * performance benefits of paravirtualization. In the U-Boot case, the guest
+ * is U-Boot itself, while the virtual environment are normally QEMU targets
+ * like ARM, RISC-V and x86.
+ *
+ * See http://docs.oasis-open.org/virtio/virtio/v1.0/virtio-v1.0.pdf for
+ * the VirtIO specification v1.0.
+ *
+ * This file is largely based on Linux kernel virtio_*.h files
+ */
+
+#ifndef __VIRTIO_H__
+#define __VIRTIO_H__
+
+#define VIRTIO_ID_NET 1 /* virtio net */
+#define VIRTIO_ID_BLOCK 2 /* virtio block */
+#define VIRTIO_ID_MAX_NUM 3
+
+#define VIRTIO_NET_DRV_NAME "virtio-net"
+#define VIRTIO_BLK_DRV_NAME "virtio-blk"
+
+/* Status byte for guest to report progress, and synchronize features */
+
+/* We have seen device and processed generic fields (VIRTIO_CONFIG_F_VIRTIO) */
+#define VIRTIO_CONFIG_S_ACKNOWLEDGE 1
+/* We have found a driver for the device */
+#define VIRTIO_CONFIG_S_DRIVER 2
+/* Driver has used its parts of the config, and is happy */
+#define VIRTIO_CONFIG_S_DRIVER_OK 4
+/* Driver has finished configuring features */
+#define VIRTIO_CONFIG_S_FEATURES_OK 8
+/* Device entered invalid state, driver must reset it */
+#define VIRTIO_CONFIG_S_NEEDS_RESET 0x40
+/* We've given up on this device */
+#define VIRTIO_CONFIG_S_FAILED 0x80
+
+/*
+ * Virtio feature bits VIRTIO_TRANSPORT_F_START through VIRTIO_TRANSPORT_F_END
+ * are reserved for the transport being used (eg: virtio_ring, virtio_pci etc.),
+ * the rest are per-device feature bits.
+ */
+#define VIRTIO_TRANSPORT_F_START 28
+#define VIRTIO_TRANSPORT_F_END 38
+
+#ifndef VIRTIO_CONFIG_NO_LEGACY
+/*
+ * Do we get callbacks when the ring is completely used,
+ * even if we've suppressed them?
+ */
+#define VIRTIO_F_NOTIFY_ON_EMPTY 24
+
+/* Can the device handle any descriptor layout? */
+#define VIRTIO_F_ANY_LAYOUT 27
+#endif /* VIRTIO_CONFIG_NO_LEGACY */
+
+/* v1.0 compliant */
+#define VIRTIO_F_VERSION_1 32
+
+/*
+ * If clear - device has the IOMMU bypass quirk feature.
+ * If set - use platform tools to detect the IOMMU.
+ *
+ * Note the reverse polarity (compared to most other features),
+ * this is for compatibility with legacy systems.
+ */
+#define VIRTIO_F_IOMMU_PLATFORM 33
+
+/* Does the device support Single Root I/O Virtualization? */
+#define VIRTIO_F_SR_IOV 37
+
+/**
+ * virtio scatter-gather struct
+ *
+ * @addr: sg buffer address
+ * @lengh: sg buffer length
+ */
+struct virtio_sg {
+ void *addr;
+ size_t length;
+};
+
+struct virtqueue;
+
+/* virtio bus operations */
+struct dm_virtio_ops {
+ /**
+ * get_config() - read the value of a configuration field
+ *
+ * @vdev: the real virtio device
+ * @offset: the offset of the configuration field
+ * @buf: the buffer to write the field value into
+ * @len: the length of the buffer
+ * @return 0 if OK, -ve on error
+ */
+ int (*get_config)(struct udevice *vdev, unsigned int offset,
+ void *buf, unsigned int len);
+ /**
+ * set_config() - write the value of a configuration field
+ *
+ * @vdev: the real virtio device
+ * @offset: the offset of the configuration field
+ * @buf: the buffer to read the field value from
+ * @len: the length of the buffer
+ * @return 0 if OK, -ve on error
+ */
+ int (*set_config)(struct udevice *vdev, unsigned int offset,
+ const void *buf, unsigned int len);
+ /**
+ * generation() - config generation counter
+ *
+ * @vdev: the real virtio device
+ * @counter: the returned config generation counter
+ * @return 0 if OK, -ve on error
+ */
+ int (*generation)(struct udevice *vdev, u32 *counter);
+ /**
+ * get_status() - read the status byte
+ *
+ * @vdev: the real virtio device
+ * @status: the returned status byte
+ * @return 0 if OK, -ve on error
+ */
+ int (*get_status)(struct udevice *vdev, u8 *status);
+ /**
+ * set_status() - write the status byte
+ *
+ * @vdev: the real virtio device
+ * @status: the new status byte
+ * @return 0 if OK, -ve on error
+ */
+ int (*set_status)(struct udevice *vdev, u8 status);
+ /**
+ * reset() - reset the device
+ *
+ * @vdev: the real virtio device
+ * @return 0 if OK, -ve on error
+ */
+ int (*reset)(struct udevice *vdev);
+ /**
+ * get_features() - get the array of feature bits for this device
+ *
+ * @vdev: the real virtio device
+ * @features: the first 32 feature bits (all we currently need)
+ * @return 0 if OK, -ve on error
+ */
+ int (*get_features)(struct udevice *vdev, u64 *features);
+ /**
+ * set_features() - confirm what device features we'll be using
+ *
+ * @vdev: the real virtio device
+ * @return 0 if OK, -ve on error
+ */
+ int (*set_features)(struct udevice *vdev);
+ /**
+ * find_vqs() - find virtqueues and instantiate them
+ *
+ * @vdev: the real virtio device
+ * @nvqs: the number of virtqueues to find
+ * @vqs: on success, includes new virtqueues
+ * @return 0 if OK, -ve on error
+ */
+ int (*find_vqs)(struct udevice *vdev, unsigned int nvqs,
+ struct virtqueue *vqs[]);
+ /**
+ * del_vqs() - free virtqueues found by find_vqs()
+ *
+ * @vdev: the real virtio device
+ * @return 0 if OK, -ve on error
+ */
+ int (*del_vqs)(struct udevice *vdev);
+ /**
+ * notify() - notify the device to process the queue
+ *
+ * @vdev: the real virtio device
+ * @vq: virtqueue to process
+ * @return 0 if OK, -ve on error
+ */
+ int (*notify)(struct udevice *vdev, struct virtqueue *vq);
+};
+
+/* Get access to a virtio bus' operations */
+#define virtio_get_ops(dev) ((struct dm_virtio_ops *)(dev)->driver->ops)
+
+/**
+ * virtio uclass per device private data
+ *
+ * @vqs: virtualqueue for the virtio device
+ * @vdev: the real virtio device underneath
+ * @legacy: is it a legacy device?
+ * @device: virtio device ID
+ * @vendor: virtio vendor ID
+ * @features: negotiated supported features
+ * @feature_table: an array of feature supported by the driver
+ * @feature_table_size: number of entries in the feature table array
+ * @feature_table_legacy: same as feature_table but working in legacy mode
+ * @feature_table_size_legacy: number of entries in feature table legacy array
+ */
+struct virtio_dev_priv {
+ struct list_head vqs;
+ struct udevice *vdev;
+ bool legacy;
+ u32 device;
+ u32 vendor;
+ u64 features;
+ const u32 *feature_table;
+ u32 feature_table_size;
+ const u32 *feature_table_legacy;
+ u32 feature_table_size_legacy;
+};
+
+/**
+ * virtio_get_config() - read the value of a configuration field
+ *
+ * @vdev: the real virtio device
+ * @offset: the offset of the configuration field
+ * @buf: the buffer to write the field value into
+ * @len: the length of the buffer
+ * @return 0 if OK, -ve on error
+ */
+int virtio_get_config(struct udevice *vdev, unsigned int offset,
+ void *buf, unsigned int len);
+
+/**
+ * virtio_set_config() - write the value of a configuration field
+ *
+ * @vdev: the real virtio device
+ * @offset: the offset of the configuration field
+ * @buf: the buffer to read the field value from
+ * @len: the length of the buffer
+ * @return 0 if OK, -ve on error
+ */
+int virtio_set_config(struct udevice *vdev, unsigned int offset,
+ void *buf, unsigned int len);
+
+/**
+ * virtio_generation() - config generation counter
+ *
+ * @vdev: the real virtio device
+ * @counter: the returned config generation counter
+ * @return 0 if OK, -ve on error
+ */
+int virtio_generation(struct udevice *vdev, u32 *counter);
+
+/**
+ * virtio_get_status() - read the status byte
+ *
+ * @vdev: the real virtio device
+ * @status: the returned status byte
+ * @return 0 if OK, -ve on error
+ */
+int virtio_get_status(struct udevice *vdev, u8 *status);
+
+/**
+ * virtio_set_status() - write the status byte
+ *
+ * @vdev: the real virtio device
+ * @status: the new status byte
+ * @return 0 if OK, -ve on error
+ */
+int virtio_set_status(struct udevice *vdev, u8 status);
+
+/**
+ * virtio_reset() - reset the device
+ *
+ * @vdev: the real virtio device
+ * @return 0 if OK, -ve on error
+ */
+int virtio_reset(struct udevice *vdev);
+
+/**
+ * virtio_get_features() - get the array of feature bits for this device
+ *
+ * @vdev: the real virtio device
+ * @features: the first 32 feature bits (all we currently need)
+ * @return 0 if OK, -ve on error
+ */
+int virtio_get_features(struct udevice *vdev, u64 *features);
+
+/**
+ * virtio_set_features() - confirm what device features we'll be using
+ *
+ * @vdev: the real virtio device
+ * @return 0 if OK, -ve on error
+ */
+int virtio_set_features(struct udevice *vdev);
+
+/**
+ * virtio_find_vqs() - find virtqueues and instantiate them
+ *
+ * @vdev: the real virtio device
+ * @nvqs: the number of virtqueues to find
+ * @vqs: on success, includes new virtqueues
+ * @return 0 if OK, -ve on error
+ */
+int virtio_find_vqs(struct udevice *vdev, unsigned int nvqs,
+ struct virtqueue *vqs[]);
+
+/**
+ * virtio_del_vqs() - free virtqueues found by find_vqs()
+ *
+ * @vdev: the real virtio device
+ * @return 0 if OK, -ve on error
+ */
+int virtio_del_vqs(struct udevice *vdev);
+
+/**
+ * virtio_notify() - notify the device to process the queue
+ *
+ * @vdev: the real virtio device
+ * @vq: virtqueue to process
+ * @return 0 if OK, -ve on error
+ */
+int virtio_notify(struct udevice *vdev, struct virtqueue *vq);
+
+/**
+ * virtio_add_status() - helper to set a new status code to the device
+ *
+ * @vdev: the real virtio device
+ * @status: new status code to be added
+ */
+void virtio_add_status(struct udevice *vdev, u8 status);
+
+/**
+ * virtio_finalize_features() - helper to finalize features
+ *
+ * @vdev: the real virtio device
+ * @return 0 if OK, -ve on error
+ */
+int virtio_finalize_features(struct udevice *vdev);
+
+/**
+ * virtio_driver_features_init() - initialize driver supported features
+ *
+ * This fills in the virtio device parent per child private data with the given
+ * information, which contains driver supported features and legacy features.
+ *
+ * This API should be called in the virtio device driver's bind method, so that
+ * later virtio transport uclass driver can utilize the driver supplied features
+ * to negotiate with the device on the final supported features.
+ *
+ * @priv: virtio uclass per device private data
+ * @feature: an array of feature supported by the driver
+ * @feature_size: number of entries in the feature table array
+ * @feature_legacy: same as feature_table but working in legacy mode
+ * @feature_legacy_size:number of entries in feature table legacy array
+ */
+void virtio_driver_features_init(struct virtio_dev_priv *priv,
+ const u32 *feature,
+ u32 feature_size,
+ const u32 *feature_legacy,
+ u32 feature_legacy_size);
+
+/**
+ * virtio_init() - helper to enumerate all known virtio devices
+ *
+ * @return 0 if OK, -ve on error
+ */
+int virtio_init(void);
+
+static inline u16 __virtio16_to_cpu(bool little_endian, __virtio16 val)
+{
+ if (little_endian)
+ return le16_to_cpu((__force __le16)val);
+ else
+ return be16_to_cpu((__force __be16)val);
+}
+
+static inline __virtio16 __cpu_to_virtio16(bool little_endian, u16 val)
+{
+ if (little_endian)
+ return (__force __virtio16)cpu_to_le16(val);
+ else
+ return (__force __virtio16)cpu_to_be16(val);
+}
+
+static inline u32 __virtio32_to_cpu(bool little_endian, __virtio32 val)
+{
+ if (little_endian)
+ return le32_to_cpu((__force __le32)val);
+ else
+ return be32_to_cpu((__force __be32)val);
+}
+
+static inline __virtio32 __cpu_to_virtio32(bool little_endian, u32 val)
+{
+ if (little_endian)
+ return (__force __virtio32)cpu_to_le32(val);
+ else
+ return (__force __virtio32)cpu_to_be32(val);
+}
+
+static inline u64 __virtio64_to_cpu(bool little_endian, __virtio64 val)
+{
+ if (little_endian)
+ return le64_to_cpu((__force __le64)val);
+ else
+ return be64_to_cpu((__force __be64)val);
+}
+
+static inline __virtio64 __cpu_to_virtio64(bool little_endian, u64 val)
+{
+ if (little_endian)
+ return (__force __virtio64)cpu_to_le64(val);
+ else
+ return (__force __virtio64)cpu_to_be64(val);
+}
+
+/**
+ * __virtio_test_bit - helper to test feature bits
+ *
+ * For use by transports. Devices should normally use virtio_has_feature,
+ * which includes more checks.
+ *
+ * @udev: the transport device
+ * @fbit: the feature bit
+ */
+static inline bool __virtio_test_bit(struct udevice *udev, unsigned int fbit)
+{
+ struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(udev);
+
+ /* Did you forget to fix assumptions on max features? */
+ if (__builtin_constant_p(fbit))
+ BUILD_BUG_ON(fbit >= 64);
+ else
+ WARN_ON(fbit >= 64);
+
+ return uc_priv->features & BIT_ULL(fbit);
+}
+
+/**
+ * __virtio_set_bit - helper to set feature bits
+ *
+ * For use by transports.
+ *
+ * @udev: the transport device
+ * @fbit: the feature bit
+ */
+static inline void __virtio_set_bit(struct udevice *udev, unsigned int fbit)
+{
+ struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(udev);
+
+ /* Did you forget to fix assumptions on max features? */
+ if (__builtin_constant_p(fbit))
+ BUILD_BUG_ON(fbit >= 64);
+ else
+ WARN_ON(fbit >= 64);
+
+ uc_priv->features |= BIT_ULL(fbit);
+}
+
+/**
+ * __virtio_clear_bit - helper to clear feature bits
+ *
+ * For use by transports.
+ *
+ * @vdev: the transport device
+ * @fbit: the feature bit
+ */
+static inline void __virtio_clear_bit(struct udevice *udev, unsigned int fbit)
+{
+ struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(udev);
+
+ /* Did you forget to fix assumptions on max features? */
+ if (__builtin_constant_p(fbit))
+ BUILD_BUG_ON(fbit >= 64);
+ else
+ WARN_ON(fbit >= 64);
+
+ uc_priv->features &= ~BIT_ULL(fbit);
+}
+
+/**
+ * virtio_has_feature - helper to determine if this device has this feature
+ *
+ * Note this API is only usable after the virtio device driver's bind phase,
+ * as the feature has been negotiated between the device and the driver.
+ *
+ * @vdev: the virtio device
+ * @fbit: the feature bit
+ */
+static inline bool virtio_has_feature(struct udevice *vdev, unsigned int fbit)
+{
+ if (!(vdev->flags & DM_FLAG_BOUND))
+ WARN_ON(true);
+
+ return __virtio_test_bit(vdev->parent, fbit);
+}
+
+static inline bool virtio_legacy_is_little_endian(void)
+{
+#ifdef __LITTLE_ENDIAN
+ return true;
+#else
+ return false;
+#endif
+}
+
+static inline bool virtio_is_little_endian(struct udevice *vdev)
+{
+ struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(vdev->parent);
+
+ return !uc_priv->legacy || virtio_legacy_is_little_endian();
+}
+
+/* Memory accessors */
+static inline u16 virtio16_to_cpu(struct udevice *vdev, __virtio16 val)
+{
+ return __virtio16_to_cpu(virtio_is_little_endian(vdev), val);
+}
+
+static inline __virtio16 cpu_to_virtio16(struct udevice *vdev, u16 val)
+{
+ return __cpu_to_virtio16(virtio_is_little_endian(vdev), val);
+}
+
+static inline u32 virtio32_to_cpu(struct udevice *vdev, __virtio32 val)
+{
+ return __virtio32_to_cpu(virtio_is_little_endian(vdev), val);
+}
+
+static inline __virtio32 cpu_to_virtio32(struct udevice *vdev, u32 val)
+{
+ return __cpu_to_virtio32(virtio_is_little_endian(vdev), val);
+}
+
+static inline u64 virtio64_to_cpu(struct udevice *vdev, __virtio64 val)
+{
+ return __virtio64_to_cpu(virtio_is_little_endian(vdev), val);
+}
+
+static inline __virtio64 cpu_to_virtio64(struct udevice *vdev, u64 val)
+{
+ return __cpu_to_virtio64(virtio_is_little_endian(vdev), val);
+}
+
+/* Read @count fields, @bytes each */
+static inline void __virtio_cread_many(struct udevice *vdev,
+ unsigned int offset,
+ void *buf, size_t count, size_t bytes)
+{
+ u32 old, gen;
+ int i;
+
+ /* no need to check return value as generation can be optional */
+ virtio_generation(vdev, &gen);
+ do {
+ old = gen;
+
+ for (i = 0; i < count; i++)
+ virtio_get_config(vdev, offset + bytes * i,
+ buf + i * bytes, bytes);
+
+ virtio_generation(vdev, &gen);
+ } while (gen != old);
+}
+
+static inline void virtio_cread_bytes(struct udevice *vdev,
+ unsigned int offset,
+ void *buf, size_t len)
+{
+ __virtio_cread_many(vdev, offset, buf, len, 1);
+}
+
+static inline u8 virtio_cread8(struct udevice *vdev, unsigned int offset)
+{
+ u8 ret;
+
+ virtio_get_config(vdev, offset, &ret, sizeof(ret));
+ return ret;
+}
+
+static inline void virtio_cwrite8(struct udevice *vdev,
+ unsigned int offset, u8 val)
+{
+ virtio_set_config(vdev, offset, &val, sizeof(val));
+}
+
+static inline u16 virtio_cread16(struct udevice *vdev,
+ unsigned int offset)
+{
+ u16 ret;
+
+ virtio_get_config(vdev, offset, &ret, sizeof(ret));
+ return virtio16_to_cpu(vdev, (__force __virtio16)ret);
+}
+
+static inline void virtio_cwrite16(struct udevice *vdev,
+ unsigned int offset, u16 val)
+{
+ val = (__force u16)cpu_to_virtio16(vdev, val);
+ virtio_set_config(vdev, offset, &val, sizeof(val));
+}
+
+static inline u32 virtio_cread32(struct udevice *vdev,
+ unsigned int offset)
+{
+ u32 ret;
+
+ virtio_get_config(vdev, offset, &ret, sizeof(ret));
+ return virtio32_to_cpu(vdev, (__force __virtio32)ret);
+}
+
+static inline void virtio_cwrite32(struct udevice *vdev,
+ unsigned int offset, u32 val)
+{
+ val = (__force u32)cpu_to_virtio32(vdev, val);
+ virtio_set_config(vdev, offset, &val, sizeof(val));
+}
+
+static inline u64 virtio_cread64(struct udevice *vdev,
+ unsigned int offset)
+{
+ u64 ret;
+
+ __virtio_cread_many(vdev, offset, &ret, 1, sizeof(ret));
+ return virtio64_to_cpu(vdev, (__force __virtio64)ret);
+}
+
+static inline void virtio_cwrite64(struct udevice *vdev,
+ unsigned int offset, u64 val)
+{
+ val = (__force u64)cpu_to_virtio64(vdev, val);
+ virtio_set_config(vdev, offset, &val, sizeof(val));
+}
+
+/* Config space read accessor */
+#define virtio_cread(vdev, structname, member, ptr) \
+ do { \
+ /* Must match the member's type, and be integer */ \
+ if (!typecheck(typeof((((structname *)0)->member)), *(ptr))) \
+ (*ptr) = 1; \
+ \
+ switch (sizeof(*ptr)) { \
+ case 1: \
+ *(ptr) = virtio_cread8(vdev, \
+ offsetof(structname, member)); \
+ break; \
+ case 2: \
+ *(ptr) = virtio_cread16(vdev, \
+ offsetof(structname, member)); \
+ break; \
+ case 4: \
+ *(ptr) = virtio_cread32(vdev, \
+ offsetof(structname, member)); \
+ break; \
+ case 8: \
+ *(ptr) = virtio_cread64(vdev, \
+ offsetof(structname, member)); \
+ break; \
+ default: \
+ WARN_ON(true); \
+ } \
+ } while (0)
+
+/* Config space write accessor */
+#define virtio_cwrite(vdev, structname, member, ptr) \
+ do { \
+ /* Must match the member's type, and be integer */ \
+ if (!typecheck(typeof((((structname *)0)->member)), *(ptr))) \
+ WARN_ON((*ptr) == 1); \
+ \
+ switch (sizeof(*ptr)) { \
+ case 1: \
+ virtio_cwrite8(vdev, \
+ offsetof(structname, member), \
+ *(ptr)); \
+ break; \
+ case 2: \
+ virtio_cwrite16(vdev, \
+ offsetof(structname, member), \
+ *(ptr)); \
+ break; \
+ case 4: \
+ virtio_cwrite32(vdev, \
+ offsetof(structname, member), \
+ *(ptr)); \
+ break; \
+ case 8: \
+ virtio_cwrite64(vdev, \
+ offsetof(structname, member), \
+ *(ptr)); \
+ break; \
+ default: \
+ WARN_ON(true); \
+ } \
+ } while (0)
+
+/* Conditional config space accessors */
+#define virtio_cread_feature(vdev, fbit, structname, member, ptr) \
+ ({ \
+ int _r = 0; \
+ if (!virtio_has_feature(vdev, fbit)) \
+ _r = -ENOENT; \
+ else \
+ virtio_cread(vdev, structname, member, ptr); \
+ _r; \
+ })
+
+#endif /* __VIRTIO_H__ */