[RFC,v1,2/2] emudev: Add library for emulated device

diff --git a/lib/librte_emudev/rte_emudev.h b/lib/librte_emudev/rte_emudev.h
new file mode 100644
index 000000000..2ffc4dbe0
--- /dev/null
+++ b/lib/librte_emudev/rte_emudev.h
@@ -0,0 +1,315 @@ 
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2020 Intel Corporation
+ */
+
+#ifndef _RTE_EMUDEV_H_
+#define _RTE_EMUDEV_H_
+
+#include <rte_config.h>
+#include <rte_malloc.h>
+#include <rte_ring.h>
+
+typedef void *rte_emudev_conf_t;
+typedef void *rte_emudev_attr_t;
+typedef void *rte_emudev_mem_table_t;
+typedef char *emu_dev_type_t;
+
+struct rte_emu_dev;
+
+struct emu_dev_info {
+	emu_dev_type_t dev_type;
+	uint32_t max_qp_num;
+	uint32_t max_event_num;
+};
+
+struct emu_dev_q_info {
+	uint64_t base;
+	uint64_t size;
+	uint32_t doorbell_id;
+	uint32_t irq_vector;
+	void *priv;
+};
+
+struct emu_dev_irq_info {
+	uint32_t vector;
+	int fd;
+	void *priv;
+};
+
+struct emu_dev_db_info {
+	uint32_t id;
+	uint32_t flag;
+#define EMU_DEV_DB_FD	(0x1 << 0)
+#define EMU_DEV_DB_MEM	(0x1 << 1)
+	union {
+		int fd;
+		struct {
+			uint64_t base;
+			uint64_t size;
+		} mem;
+	} data;
+	void *priv;
+};
+
+/**
+ * Back-end driver and emualated device provider should have
+ * the same definiton of events and events message.
+ */
+struct emu_dev_event_channel {
+	int fd;
+	struct rte_ring *queue;
+};
+
+struct emu_dev_attr_info {
+	const char *attr_name;
+	rte_emudev_attr_t attr;
+};
+
+struct emu_dev_ops {
+	int (*dev_start)(struct rte_emu_dev *dev);
+	void (*dev_stop)(struct rte_emu_dev *dev);
+	int (*dev_configure)(struct rte_emu_dev *dev,
+		rte_emudev_conf_t dev_conf);
+	int (*dev_close)(struct rte_emu_dev *dev);
+	struct emu_dev_info *(*get_dev_info)(struct rte_emu_dev *dev);
+	int (*subscribe_event)(struct rte_emu_dev *dev,
+		const struct emu_dev_event_channel *ev_chnl);
+	int (*unsubscribe_event)(struct rte_emu_dev *dev,
+		const struct emu_dev_event_channel *ev_chnl);
+	rte_emudev_mem_table_t (*get_mem_table)(struct rte_emu_dev *dev);
+	struct emu_dev_q_info *(*get_queue_info)(struct rte_emu_dev *dev,
+		uint32_t queue);
+	struct emu_dev_irq_info *(*get_irq_info)(struct rte_emu_dev *dev,
+		uint32_t vector);
+	struct emu_dev_db_info *(*get_db_info)(struct rte_emu_dev *dev,
+		uint32_t doorbell);
+	rte_emudev_attr_t (*get_attr)(struct rte_emu_dev *dev,
+		const char *attr_name);
+	int (*set_attr)(struct rte_emu_dev *dev, const char *attr_name,
+		rte_emudev_attr_t attr);
+	int (*region_map)(struct rte_emu_dev *dev, const char *region_name,
+		uint16_t region_size, uint64_t *base_addr);
+};
+
+struct rte_emu_dev {
+	struct rte_device *device;
+	const struct emu_dev_ops *dev_ops;
+	const struct emu_dev_event_channel *ev_chnl;
+	struct emu_dev_info *dev_info;
+	uint16_t num_attr;
+	struct emu_dev_attr_info **attr;
+	void *priv_data;
+} __rte_cache_aligned;
+
+/**
+ * Note that 'rte_emu_dev_allocate','rte_emu_dev_release' and
+ * 'rte_emu_dev_allocated' should be called by emulated device
+ * provider.
+ * /
+
+/**
+ * Allocate a new emudev for an emulation device and retures the pointer
+ * to the emudev.
+ *
+ * @param name
+ *  Name of the emudev
+ * @return
+ *  Pointer to rte_emu_dev on success, NULL on failure
+ */
+struct rte_emu_dev *
+rte_emu_dev_allocate(const char *name);
+
+/**
+ * Release the emudev.
+ *
+ * @param dev
+ *  The emulated device
+ * @return
+ *  0 on success, -1 on failure
+ */
+int
+rte_emu_dev_release(struct rte_emu_dev *dev);
+
+/**
+ * Find an emudev using name.
+ *
+ * @param name
+ *  Name of the emudev
+ * @return
+ *  Pointer to rte_emu_dev on success, NULL on failure
+ */
+struct rte_emu_dev *
+rte_emu_dev_allocated(const char *name);
+
+/**
+ * Start an emulation device.
+ *
+ * @param dev_id
+ *  Device ID of emudev
+ * @return
+ *  0 on success, -1 on failure
+ */
+int rte_emu_dev_start(uint16_t dev_id);
+
+/**
+ * Stop an emulation device.
+ *
+ * @param dev_id
+ *  Device ID of emudev
+ */
+void rte_emu_dev_stop(uint16_t dev_id);
+
+/**
+ * Configure an emulation device.
+ *
+ * @param dev_id
+ *  Device ID of emudev
+ * @param dev_conf
+ *  Device configure info
+ * @return
+ *  0 on success, -1 on failure
+ */
+int rte_emu_dev_configure(uint16_t dev_id, rte_emudev_conf_t dev_conf);
+
+/**
+ * Close an emulation device.
+ *
+ * @param dev_id
+ *  Device ID of emudev
+ */
+void rte_emu_dev_close(uint16_t dev_id);
+
+/* Note that below APIs should only be called by back-end driver */
+
+/**
+ * Back-end driver subscribes events of the emulated device.
+ *
+ * @param dev_id
+ *  Device ID of emudev
+ * @param ev_chnl
+ *  Event channel that events should be passed to
+ * @return
+ *  0 on success, -1 on failure
+ */
+int rte_emu_subscribe_event(uint16_t dev_id,
+		const struct emu_dev_event_channel *ev_chnl);
+
+/**
+ * Back-end driver unsubscribes events of the emulated device.
+ *
+ * @param dev_id
+ *  Device ID of emudev
+ * @param set
+ *  Event channel that events should be passed to
+ * @return
+ *  0 on success, -1 on failure
+ */
+int rte_emu_unsubscribe_event(uint16_t dev_id,
+		const struct emu_dev_event_channel *ev_chnl);
+
+/**
+ * Back-end driver gets the device info of the emulated device.
+ *
+ * @param dev_id
+ *  Device ID of emudev
+ * @return
+ *  Pointer to dev info on success, NULL on failure
+ */
+struct emu_dev_info *rte_emu_get_dev_info(uint16_t dev_id);
+
+/**
+ * Get the memory table content and operations of the emulated device.
+ *
+ * @param dev_id
+ *  Device ID of emudev
+ * @return
+ *  Pointer to memory table on success, NULL on failure
+ */
+rte_emudev_mem_table_t rte_emu_get_mem_table(uint16_t dev_id);
+
+/**
+ * Get queue info of the emudev.
+ *
+ * @param dev_id
+ *  Device ID of emudev
+ * @param queue
+ *  Queue ID of emudev
+ * @return
+ *  Pointer to queue info on success, NULL on failure
+ */
+struct emu_dev_q_info *rte_emu_get_queue_info(uint16_t dev_id,
+		uint32_t queue);
+
+/**
+ * Get irq info of the emudev.
+ *
+ * @param dev_id
+ *  Device ID of emudev
+ * @param vector
+ *  Interrupt vector
+ * @return
+ *  Pointer to irq info on success, NULL on failure
+ */
+struct emu_dev_irq_info *rte_emu_get_irq_info(uint16_t dev_id,
+		uint32_t vector);
+
+/**
+ * Get doorbell info of the emudev.
+ *
+ * @param dev_id
+ *  Device ID of emudev
+ * @param doorbell
+ *  Doorbell ID
+ * @return
+ *  Pointer to doorbell info on success, NULL on failure
+ */
+struct emu_dev_db_info *rte_emu_get_db_info(uint16_t dev_id,
+		uint32_t doorbell);
+
+/**
+ * Set attribute of the emudev.
+ *
+ * @param dev_id
+ *  Device ID of emudev
+ * @param attr_name
+ *  Opaque object representing an attribute in implementation.
+ * @param attr
+ *  Pointer to attribute
+ * @return
+ *  0 on success, -1 on failure
+ */
+int rte_emu_set_attr(uint16_t dev_id, const char *attr_name,
+	rte_emudev_attr_t attr);
+
+/**
+ * Get attribute of the emudev.
+ *
+ * @param dev_id
+ *  Device ID of emudev
+ * @param attr_name
+ *  Opaque object representing an attribute in implementation.
+ * @return
+ *  Corresponding attr on success, NULL on failure
+ */
+rte_emudev_attr_t rte_emu_get_attr(uint16_t dev_id, const char *attr_name);
+
+/**
+ * Back-end driver maps a region to the emulated device.
+ * Region name identifies the meaning of the region and the emulated
+ * device and the back-end driver should have the same definition of
+ * region name and its meaning.
+ *
+ * @param dev_id
+ *  Device ID of emudev
+ * @param region_name
+ *  .
+ * @param attr
+ *  Pointer to attribute
+ * @return
+ *  0 on success, -1 on failure
+ */
+int rte_emu_region_map(uint16_t dev_id, const char *region_name,
+	uint16_t region_size, uint64_t *base_addr);
+
+extern struct rte_emu_dev rte_emu_devices[];
+#endif /* _RTE_EMUDEV_H_ */