/*
 * Copyright (c) Jan Pochyla, SatoshiLabs
 *
 * Licensed under TREZOR License
 * see LICENSE file for details
 */

#include <stddef.h>

typedef struct __attribute__((packed)) {
    uint8_t bFunctionLength;
    uint8_t bDescriptorType;
    uint8_t bDescriptorSubtype;
    uint16_t bcdCDC;
} usb_vcp_header_descriptor_t;

typedef struct __attribute__((packed)) {
    uint8_t bFunctionLength;
    uint8_t bDescriptorType;
    uint8_t bDescriptorSubtype;
    uint8_t bmCapabilities;
    uint8_t bDataInterface;
} usb_vcp_cm_descriptor_t;

typedef struct __attribute__((packed)) {
    uint8_t bFunctionLength;
    uint8_t bDescriptorType;
    uint8_t bDescriptorSubtype;
    uint8_t bmCapabilities;
} usb_vcp_acm_descriptor_t;

typedef struct __attribute__((packed)) {
    uint8_t bFunctionLength;
    uint8_t bDescriptorType;
    uint8_t bDescriptorSubtype;
    uint8_t bControlInterface;
    uint8_t bSubordinateInterface0;
} usb_vcp_union_descriptor_t;

typedef struct __attribute__((packed)) {
    usb_interface_assoc_descriptor_t assoc;
    usb_interface_descriptor_t iface_cdc;
    usb_vcp_header_descriptor_t fheader; // Class-Specific Descriptor Header Format
    usb_vcp_cm_descriptor_t fcm;         // Call Management Functional Descriptor
    usb_vcp_acm_descriptor_t facm;       // Abstract Control Management Functional Descriptor
    usb_vcp_union_descriptor_t funion;   // Union Interface Functional Descriptor
    usb_endpoint_descriptor_t ep_cmd;
    usb_interface_descriptor_t iface_data;
    usb_endpoint_descriptor_t ep_in;
    usb_endpoint_descriptor_t ep_out;
} usb_vcp_descriptor_block_t;

typedef struct __attribute__((packed)) {
    uint32_t dwDTERate;
    uint8_t bCharFormat; // usb_cdc_line_coding_bCharFormat_t
    uint8_t bParityType; // usb_cdc_line_coding_bParityType_t
    uint8_t bDataBits;
} usb_cdc_line_coding_t;

typedef enum {
    USB_CDC_1_STOP_BITS   = 0,
    USB_CDC_1_5_STOP_BITS = 1,
    USB_CDC_2_STOP_BITS   = 2,
} usb_cdc_line_coding_bCharFormat_t;

typedef enum {
    USB_CDC_NO_PARITY    = 0,
    USB_CDC_ODD_PARITY   = 1,
    USB_CDC_EVEN_PARITY  = 2,
    USB_CDC_MARK_PARITY  = 3,
    USB_CDC_SPACE_PARITY = 4,
} usb_cdc_line_coding_bParityType_t;

/* usb_vcp_info_t contains all information for setting up a VCP interface.  All
 * passed pointers need to live at least until the interface is disabled
 * (usb_stop is called). */
typedef struct {
    uint8_t *tx_packet;       // Buffer for one packet, with length of at least max_packet_len bytes
    uint8_t *tx_buffer;       // Buffer for IN EP ring buffer, with length of at least tx_buffer_len bytes
    uint8_t *rx_packet;       // Buffer for one packet, with length of at least max_packet_len bytes
    uint8_t *rx_buffer;       // Buffer for OUT EP ring buffer, with length of at least rx_buffer_len bytes
    size_t tx_buffer_len;     // Length of tx_buffer, needs to be a power of 2
    size_t rx_buffer_len;     // Length of rx_buffer, needs to be a power of 2
    void (*rx_intr_fn)(void); // Callback called from usb_vcp_class_data_out IRQ handler if rx_intr_byte matches
    uint8_t rx_intr_byte;     // Value matched against every received byte
    uint8_t iface_num;        // Address of this VCP interface
    uint8_t data_iface_num;   // Address of data interface of the VCP interface association
    uint8_t ep_cmd;           // Address of IN CMD endpoint (with the highest bit set)
    uint8_t ep_in;            // Address of IN endpoint (with the highest bit set)
    uint8_t ep_out;           // Address of OUT endpoint
    uint8_t polling_interval; // In units of 1ms
    uint8_t max_packet_len;   // Length of the biggest packet, and of tx_packet and rx_packet
} usb_vcp_info_t;

/* usb_rbuf_t is used internally for the RX/TX buffering. */
typedef struct {
    size_t cap;
    volatile size_t read;
    volatile size_t write;
    uint8_t *buf;
} usb_rbuf_t;

// Maximal length of packets on IN CMD EP
#define USB_CDC_MAX_CMD_PACKET_LEN      0x08

/* usb_vcp_state_t encapsulates all state used by enabled VCP interface.  It
 * needs to be completely initialized in usb_vcp_add and reset in
 * usb_vcp_class_init.  See usb_vcp_info_t for details of the configuration
 * fields. */
typedef struct {
    const usb_vcp_descriptor_block_t *desc_block;
    usb_rbuf_t rx_ring;
    usb_rbuf_t tx_ring;
    uint8_t *rx_packet;
    uint8_t *tx_packet;
    void (*rx_intr_fn)(void);
    uint8_t rx_intr_byte;
    uint8_t ep_cmd;
    uint8_t ep_in;
    uint8_t ep_out;
    uint8_t max_packet_len;
    uint8_t ep_in_is_idle; // Set to 1 after IN endpoint gets idle
    uint8_t cmd_buffer[USB_CDC_MAX_CMD_PACKET_LEN];
} usb_vcp_state_t;

secbool __wur usb_vcp_add(const usb_vcp_info_t *vcp_info);
secbool __wur usb_vcp_can_read(uint8_t iface_num);
secbool __wur usb_vcp_can_write(uint8_t iface_num);
int __wur usb_vcp_read(uint8_t iface_num, uint8_t *buf, uint32_t len);
int __wur usb_vcp_write(uint8_t iface_num, const uint8_t *buf, uint32_t len);

int __wur usb_vcp_read_blocking(uint8_t iface_num, uint8_t *buf, uint32_t len, int timeout);
int __wur usb_vcp_write_blocking(uint8_t iface_num, const uint8_t *buf, uint32_t len, int timeout);