ena.h

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#ifndef _ENA_H
#define _ENA_H

/** @file
 *
 * Amazon ENA network driver
 *
 */

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );

#include <stdint.h>
#include <ipxe/if_ether.h>

/** BAR size */
#define ENA_BAR_SIZE 16384

/** Queue alignment */
#define ENA_ALIGN 4096

/** Number of admin queue entries */
#define ENA_AQ_COUNT 2

/** Number of admin completion queue entries */
#define ENA_ACQ_COUNT 2

/** Number of transmit queue entries */
#define ENA_TX_COUNT 16

/** Number of receive queue entries */
#define ENA_RX_COUNT 128

/** Receive queue maximum fill level */
#define ENA_RX_FILL 16

/** Base address low register offset */
#define ENA_BASE_LO 0x0

/** Base address high register offset */
#define ENA_BASE_HI 0x4

/** Capability register value */
#define ENA_CAPS( count, size ) ( ( (size) << 16 ) | ( (count) << 0 ) )

/** Admin queue base address register */
#define ENA_AQ_BASE 0x10

/** Admin queue capabilities register */
#define ENA_AQ_CAPS 0x18

/** Admin completion queue base address register */
#define ENA_ACQ_BASE 0x20

/** Admin completion queue capabilities register */
#define ENA_ACQ_CAPS 0x28

/** Admin queue doorbell register */
#define ENA_AQ_DB 0x2c

/** Maximum time to wait for admin requests */
#define ENA_ADMIN_MAX_WAIT_MS 5000

/** Device control register */
#define ENA_CTRL 0x54
#define ENA_CTRL_RESET 0x00000001UL     /**< Reset */

/** Maximum time to wait for reset */
#define ENA_RESET_MAX_WAIT_MS 1000

/** Device status register */
#define ENA_STAT 0x58
#define ENA_STAT_RESET 0x00000008UL     /**< Reset in progress */

/** Admin queue entry header */
struct ena_aq_header {
        /** Request identifier */
        uint8_t id;
        /** Reserved */
        uint8_t reserved;
        /** Opcode */
        uint8_t opcode;
        /** Flags */
        uint8_t flags;
} __attribute__ (( packed ));

/** Admin queue ownership phase flag */
#define ENA_AQ_PHASE 0x01

/** Admin completion queue entry header */
struct ena_acq_header {
        /** Request identifier */
        uint8_t id;
        /** Reserved */
        uint8_t reserved;
        /** Status */
        uint8_t status;
        /** Flags */
        uint8_t flags;
        /** Extended status */
        uint16_t ext;
        /** Consumer index */
        uint16_t cons;
} __attribute__ (( packed ));

/** Admin completion queue ownership phase flag */
#define ENA_ACQ_PHASE 0x01

/** Device attributes */
#define ENA_DEVICE_ATTRIBUTES 1

/** Device attributes */
struct ena_device_attributes {
        /** Implementation */
        uint32_t implementation;
        /** Device version */
        uint32_t version;
        /** Supported features */
        uint32_t features;
        /** Reserved */
        uint8_t reserved_a[4];
        /** Physical address width */
        uint32_t physical;
        /** Virtual address width */
        uint32_t virtual;
        /** MAC address */
        uint8_t mac[ETH_ALEN];
        /** Reserved */
        uint8_t reserved_b[2];
        /** Maximum MTU */
        uint32_t mtu;
} __attribute__ (( packed ));

/** Host attributes */
#define ENA_HOST_ATTRIBUTES 28

/** Host attributes */
struct ena_host_attributes {
        /** Host info base address */
        uint64_t info;
        /** Debug area base address */
        uint64_t debug;
        /** Debug area size */
        uint32_t debug_len;
} __attribute__ (( packed ));

/** Host information */
struct ena_host_info {
        /** Operating system type */
        uint32_t type;
        /** Operating system distribution (string) */
        char dist_str[128];
        /** Operating system distribution (numeric) */
        uint32_t dist;
        /** Kernel version (string) */
        char kernel_str[32];
        /** Kernel version (numeric) */
        uint32_t kernel;
        /** Driver version */
        uint32_t version;
        /** Linux network device features */
        uint64_t linux_features;
        /** ENA specification version */
        uint16_t spec;
        /** PCI bus:dev.fn address */
        uint16_t busdevfn;
        /** Number of CPUs */
        uint16_t cpus;
        /** Reserved */
        uint8_t reserved_a[2];
        /** Supported features */
        uint32_t features;
} __attribute__ (( packed ));

/** Linux operating system type
 *
 * There is a defined "iPXE" operating system type (with value 5).
 * However, some very broken versions of the ENA firmware will refuse
 * to allow a completion queue to be created if the "iPXE" type is
 * used.
 */
#define ENA_HOST_INFO_TYPE_LINUX 1

/** Driver version
 *
 * The driver version field is nominally used to report a version
 * number outside of the VM for consumption by humans (and potentially
 * by automated monitoring tools that could e.g. check for outdated
 * versions with known security flaws).
 *
 * However, at some point in the development of the ENA firmware, some
 * unknown person at AWS thought it would be sensible to apply a
 * machine interpretation to this field and adjust the behaviour of
 * the firmware based on its value, thereby creating a maintenance and
 * debugging nightmare for all existing and future drivers.
 *
 * Hint to engineers: if you ever find yourself writing code of the
 * form "if (version == SOME_MAGIC_NUMBER)" then something has gone
 * very, very wrong.  This *always* indicates that something is
 * broken, either in your own code or in the code with which you are
 * forced to interact.
 */
#define ENA_HOST_INFO_VERSION_WTF 0x00000002UL

/** ENA specification version */
#define ENA_HOST_INFO_SPEC_2_0 0x0200

/** Feature */
union ena_feature {
        /** Device attributes */
        struct ena_device_attributes device;
        /** Host attributes */
        struct ena_host_attributes host;
};

/** Submission queue direction */
enum ena_sq_direction {
        /** Transmit */
        ENA_SQ_TX = 0x20,
        /** Receive */
        ENA_SQ_RX = 0x40,
};

/** Create submission queue */
#define ENA_CREATE_SQ 1

/** Create submission queue request */
struct ena_create_sq_req {
        /** Header */
        struct ena_aq_header header;
        /** Direction */
        uint8_t direction;
        /** Reserved */
        uint8_t reserved_a;
        /** Policy */
        uint16_t policy;
        /** Completion queue identifier */
        uint16_t cq_id;
        /** Number of entries */
        uint16_t count;
        /** Base address */
        uint64_t address;
        /** Writeback address */
        uint64_t writeback;
        /** Reserved */
        uint8_t reserved_b[8];
} __attribute__ (( packed ));

/** Submission queue policy */
enum ena_sq_policy {
        /** Use host memory */
        ENA_SQ_HOST_MEMORY = 0x0001,
        /** Memory is contiguous */
        ENA_SQ_CONTIGUOUS = 0x0100,
};

/** Create submission queue response */
struct ena_create_sq_rsp {
        /** Header */
        struct ena_acq_header header;
        /** Submission queue identifier */
        uint16_t id;
        /** Reserved */
        uint8_t reserved[2];
        /** Doorbell register offset */
        uint32_t doorbell;
        /** LLQ descriptor ring offset */
        uint32_t llq_desc;
        /** LLQ header offset */
        uint32_t llq_data;
} __attribute__ (( packed ));

/** Destroy submission queue */
#define ENA_DESTROY_SQ 2

/** Destroy submission queue request */
struct ena_destroy_sq_req {
        /** Header */
        struct ena_aq_header header;
        /** Submission queue identifier */
        uint16_t id;
        /** Direction */
        uint8_t direction;
        /** Reserved */
        uint8_t reserved;
} __attribute__ (( packed ));

/** Destroy submission queue response */
struct ena_destroy_sq_rsp {
        /** Header */
        struct ena_acq_header header;
} __attribute__ (( packed ));

/** Create completion queue */
#define ENA_CREATE_CQ 3

/** Create completion queue request */
struct ena_create_cq_req {
        /** Header */
        struct ena_aq_header header;
        /** Interrupts enabled */
        uint8_t intr;
        /** Entry size (in 32-bit words) */
        uint8_t size;
        /** Number of entries */
        uint16_t count;
        /** MSI-X vector */
        uint32_t vector;
        /** Base address */
        uint64_t address;
} __attribute__ (( packed ));

/** Empty MSI-X vector
 *
 * Some versions of the ENA firmware will complain if the completion
 * queue's MSI-X vector field is left empty, even though the queue
 * configuration specifies that interrupts are not used.
 */
#define ENA_MSIX_NONE 0xffffffffUL

/** Create completion queue response */
struct ena_create_cq_rsp {
        /** Header */
        struct ena_acq_header header;
        /** Completion queue identifier */
        uint16_t id;
        /** Actual number of entries */
        uint16_t count;
        /** NUMA node register offset */
        uint32_t node;
        /** Doorbell register offset */
        uint32_t doorbell;
        /** Interrupt unmask register offset */
        uint32_t intr;
} __attribute__ (( packed ));

/** Destroy completion queue */
#define ENA_DESTROY_CQ 4

/** Destroy completion queue request */
struct ena_destroy_cq_req {
        /** Header */
        struct ena_aq_header header;
        /** Completion queue identifier */
        uint16_t id;
        /** Reserved */
        uint8_t reserved[2];
} __attribute__ (( packed ));

/** Destroy completion queue response */
struct ena_destroy_cq_rsp {
        /** Header */
        struct ena_acq_header header;
} __attribute__ (( packed ));

/** Get feature */
#define ENA_GET_FEATURE 8

/** Get feature request */
struct ena_get_feature_req {
        /** Header */
        struct ena_aq_header header;
        /** Length */
        uint32_t len;
        /** Address */
        uint64_t address;
        /** Flags */
        uint8_t flags;
        /** Feature identifier */
        uint8_t id;
        /** Reserved */
        uint8_t reserved[2];
} __attribute__ (( packed ));

/** Get feature response */
struct ena_get_feature_rsp {
        /** Header */
        struct ena_acq_header header;
        /** Feature */
        union ena_feature feature;
} __attribute__ (( packed ));

/** Set feature */
#define ENA_SET_FEATURE 9

/** Set feature request */
struct ena_set_feature_req {
        /** Header */
        struct ena_aq_header header;
        /** Length */
        uint32_t len;
        /** Address */
        uint64_t address;
        /** Flags */
        uint8_t flags;
        /** Feature identifier */
        uint8_t id;
        /** Reserved */
        uint8_t reserved[2];
        /** Feature */
        union ena_feature feature;
} __attribute__ (( packed ));

/** Get statistics */
#define ENA_GET_STATS 11

/** Get statistics request */
struct ena_get_stats_req {
        /** Header */
        struct ena_aq_header header;
        /** Reserved */
        uint8_t reserved_a[12];
        /** Type */
        uint8_t type;
        /** Scope */
        uint8_t scope;
        /** Reserved */
        uint8_t reserved_b[2];
        /** Queue ID */
        uint16_t queue;
        /** Device ID */
        uint16_t device;
} __attribute__ (( packed ));

/** Basic statistics */
#define ENA_STATS_TYPE_BASIC 0

/** Ethernet statistics */
#define ENA_STATS_SCOPE_ETH 1

/** My device */
#define ENA_DEVICE_MINE 0xffff

/** Get statistics response */
struct ena_get_stats_rsp {
        /** Header */
        struct ena_acq_header header;
        /** Transmit byte count */
        uint64_t tx_bytes;
        /** Transmit packet count */
        uint64_t tx_packets;
        /** Receive byte count */
        uint64_t rx_bytes;
        /** Receive packet count */
        uint64_t rx_packets;
        /** Receive drop count */
        uint64_t rx_drops;
} __attribute__ (( packed ));

/** Admin queue request */
union ena_aq_req {
        /** Header */
        struct ena_aq_header header;
        /** Create submission queue */
        struct ena_create_sq_req create_sq;
        /** Destroy submission queue */
        struct ena_destroy_sq_req destroy_sq;
        /** Create completion queue */
        struct ena_create_cq_req create_cq;
        /** Destroy completion queue */
        struct ena_destroy_cq_req destroy_cq;
        /** Get feature */
        struct ena_get_feature_req get_feature;
        /** Set feature */
        struct ena_set_feature_req set_feature;
        /** Get statistics */
        struct ena_get_stats_req get_stats;
        /** Padding */
        uint8_t pad[64];
};

/** Admin completion queue response */
union ena_acq_rsp {
        /** Header */
        struct ena_acq_header header;
        /** Create submission queue */
        struct ena_create_sq_rsp create_sq;
        /** Destroy submission queue */
        struct ena_destroy_sq_rsp destroy_sq;
        /** Create completion queue */
        struct ena_create_cq_rsp create_cq;
        /** Destroy completion queue */
        struct ena_destroy_cq_rsp destroy_cq;
        /** Get feature */
        struct ena_get_feature_rsp get_feature;
        /** Get statistics */
        struct ena_get_stats_rsp get_stats;
        /** Padding */
        uint8_t pad[64];
};

/** Admin queue */
struct ena_aq {
        /** Requests */
        union ena_aq_req *req;
        /** Producer counter */
        unsigned int prod;
};

/** Admin completion queue */
struct ena_acq {
        /** Responses */
        union ena_acq_rsp *rsp;
        /** Consumer counter */
        unsigned int cons;
        /** Phase */
        unsigned int phase;
};

/** Transmit submission queue entry */
struct ena_tx_sqe {
        /** Length */
        uint16_t len;
        /** Reserved */
        uint8_t reserved_a;
        /** Flags */
        uint8_t flags;
        /** Reserved */
        uint8_t reserved_b[3];
        /** Request identifier */
        uint8_t id;
        /** Address */
        uint64_t address;
} __attribute__ (( packed ));

/** Receive submission queue entry */
struct ena_rx_sqe {
        /** Length */
        uint16_t len;
        /** Reserved */
        uint8_t reserved_a;
        /** Flags */
        uint8_t flags;
        /** Request identifier */
        uint16_t id;
        /** Reserved */
        uint8_t reserved_b[2];
        /** Address */
        uint64_t address;
} __attribute__ (( packed ));

/** Submission queue ownership phase flag */
#define ENA_SQE_PHASE 0x01

/** This is the first descriptor */
#define ENA_SQE_FIRST 0x04

/** This is the last descriptor */
#define ENA_SQE_LAST 0x08

/** Request completion */
#define ENA_SQE_CPL 0x10

/** Transmit completion queue entry */
struct ena_tx_cqe {
        /** Request identifier */
        uint16_t id;
        /** Status */
        uint8_t status;
        /** Flags */
        uint8_t flags;
        /** Reserved */
        uint8_t reserved[2];
        /** Consumer index */
        uint16_t cons;
} __attribute__ (( packed ));

/** Transmit completion request identifier */
#define ENA_TX_CQE_ID(id) ( (id) >> 2 )

/** Receive completion queue entry */
struct ena_rx_cqe {
        /** Reserved */
        uint8_t reserved_a[3];
        /** Flags */
        uint8_t flags;
        /** Length */
        uint16_t len;
        /** Request identifier */
        uint16_t id;
        /** Reserved */
        uint8_t reserved_b[8];
} __attribute__ (( packed ));

/** Completion queue ownership phase flag */
#define ENA_CQE_PHASE 0x01

/** Submission queue */
struct ena_sq {
        /** Entries */
        union {
                /** Transmit submission queue entries */
                struct ena_tx_sqe *tx;
                /** Receive submission queue entries */
                struct ena_rx_sqe *rx;
                /** Raw data */
                void *raw;
        } sqe;
        /** Buffer IDs */
        uint8_t *ids;
        /** Doorbell register offset */
        unsigned int doorbell;
        /** Total length of entries */
        size_t len;
        /** Producer counter */
        unsigned int prod;
        /** Phase */
        unsigned int phase;
        /** Submission queue identifier */
        uint16_t id;
        /** Direction */
        uint8_t direction;
        /** Number of entries */
        uint8_t count;
        /** Maximum fill level */
        uint8_t max;
        /** Fill level (limited to completion queue size) */
        uint8_t fill;
};

/**
 * Initialise submission queue
 *
 * @v sq                Submission queue
 * @v direction         Direction
 * @v count             Number of entries
 * @v max               Maximum fill level
 * @v size              Size of each entry
 * @v ids               Buffer IDs
 */
static inline __attribute__ (( always_inline )) void
ena_sq_init ( struct ena_sq *sq, unsigned int direction, unsigned int count,
              unsigned int max, size_t size, uint8_t *ids ) {

        sq->len = ( count * size );
        sq->direction = direction;
        sq->count = count;
        sq->max = max;
        sq->ids = ids;
}

/** Completion queue */
struct ena_cq {
        /** Entries */
        union {
                /** Transmit completion queue entries */
                struct ena_tx_cqe *tx;
                /** Receive completion queue entries */
                struct ena_rx_cqe *rx;
                /** Raw data */
                void *raw;
        } cqe;
        /** Doorbell register offset */
        unsigned int doorbell;
        /** Total length of entries */
        size_t len;
        /** Consumer counter */
        unsigned int cons;
        /** Phase */
        unsigned int phase;
        /** Completion queue identifier */
        uint16_t id;
        /** Entry size (in 32-bit words) */
        uint8_t size;
        /** Requested number of entries */
        uint8_t requested;
        /** Actual number of entries */
        uint8_t actual;
        /** Actual number of entries minus one */
        uint8_t mask;
};

/**
 * Initialise completion queue
 *
 * @v cq                Completion queue
 * @v count             Number of entries
 * @v size              Size of each entry
 */
static inline __attribute__ (( always_inline )) void
ena_cq_init ( struct ena_cq *cq, unsigned int count, size_t size ) {

        cq->len = ( count * size );
        cq->size = ( size / sizeof ( uint32_t ) );
        cq->requested = count;
}

/** Queue pair */
struct ena_qp {
        /** Submission queue */
        struct ena_sq sq;
        /** Completion queue */
        struct ena_cq cq;
};

/** An ENA network card */
struct ena_nic {
        /** Registers */
        void *regs;
        /** Host info */
        struct ena_host_info *info;
        /** Admin queue */
        struct ena_aq aq;
        /** Admin completion queue */
        struct ena_acq acq;
        /** Transmit queue */
        struct ena_qp tx;
        /** Receive queue */
        struct ena_qp rx;
        /** Transmit buffer IDs */
        uint8_t tx_ids[ENA_TX_COUNT];
        /** Transmit I/O buffers, indexed by buffer ID */
        struct io_buffer *tx_iobuf[ENA_TX_COUNT];
        /** Receive buffer IDs */
        uint8_t rx_ids[ENA_RX_COUNT];
        /** Receive I/O buffers, indexed by buffer ID */
        struct io_buffer *rx_iobuf[ENA_RX_COUNT];
};

#endif /* _ENA_H */