/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _HVSI_H
#define _HVSI_H

#define VS_DATA_PACKET_HEADER           0xff
#define VS_CONTROL_PACKET_HEADER        0xfe
#define VS_QUERY_PACKET_HEADER          0xfd
#define VS_QUERY_RESPONSE_PACKET_HEADER 0xfc

/* control verbs */
#define VSV_SET_MODEM_CTL    1 /* to service processor only */
#define VSV_MODEM_CTL_UPDATE 2 /* from service processor only */
#define VSV_CLOSE_PROTOCOL   3

/* query verbs */
#define VSV_SEND_VERSION_NUMBER 1
#define VSV_SEND_MODEM_CTL_STATUS 2

/* yes, these masks are not consecutive. */
#define HVSI_TSDTR 0x01
#define HVSI_TSCD  0x20

#define HVSI_MAX_OUTGOING_DATA 12
#define HVSI_VERSION 1

struct hvsi_header {
        uint8_t  type;
        uint8_t  len;
        __be16 seqno;
} __attribute__((packed));

struct hvsi_data {
        struct hvsi_header hdr;
        uint8_t  data[HVSI_MAX_OUTGOING_DATA];
} __attribute__((packed));

struct hvsi_control {
        struct hvsi_header hdr;
        __be16 verb;
        /* optional depending on verb: */
        __be32 word;
        __be32 mask;
} __attribute__((packed));

struct hvsi_query {
        struct hvsi_header hdr;
        __be16 verb;
} __attribute__((packed));

struct hvsi_query_response {
        struct hvsi_header hdr;
        __be16 verb;
        __be16 query_seqno;
        union {
                uint8_t  version;
                __be32 mctrl_word;
        } u;
} __attribute__((packed));

/* hvsi lib struct definitions */
#define HVSI_INBUF_SIZE         255
struct tty_struct;
struct hvsi_priv {
        unsigned int    inbuf_len;      /* data in input buffer */
        unsigned char   inbuf[HVSI_INBUF_SIZE];
        unsigned int    inbuf_cur;      /* Cursor in input buffer */
        size_t          inbuf_pktlen;   /* packet length from cursor */
        atomic_t        seqno;          /* packet sequence number */
        unsigned int    opened:1;       /* driver opened */
        unsigned int    established:1;  /* protocol established */
        unsigned int    is_console:1;   /* used as a kernel console device */
        unsigned int    mctrl_update:1; /* modem control updated */
        unsigned short  mctrl;          /* modem control */
        struct tty_struct *tty;         /* tty structure */
        ssize_t (*get_chars)(uint32_t termno, u8 *buf, size_t count);
        ssize_t (*put_chars)(uint32_t termno, const u8 *buf, size_t count);
        uint32_t        termno;
};

/* hvsi lib functions */
struct hvc_struct;
extern void hvsilib_init(struct hvsi_priv *pv,
                         ssize_t (*get_chars)(uint32_t termno, u8 *buf,
                                              size_t count),
                         ssize_t (*put_chars)(uint32_t termno, const u8 *buf,
                                              size_t count),
                         int termno, int is_console);
extern int hvsilib_open(struct hvsi_priv *pv, struct hvc_struct *hp);
extern void hvsilib_close(struct hvsi_priv *pv, struct hvc_struct *hp);
extern int hvsilib_read_mctrl(struct hvsi_priv *pv);
extern int hvsilib_write_mctrl(struct hvsi_priv *pv, int dtr);
extern void hvsilib_establish(struct hvsi_priv *pv);
extern ssize_t hvsilib_get_chars(struct hvsi_priv *pv, u8 *buf, size_t count);
extern ssize_t hvsilib_put_chars(struct hvsi_priv *pv, const u8 *buf,
                                 size_t count);

#endif /* _HVSI_H */