/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */

#include "config.h"
#include "libmctp-astlpc.h"
#include "libmctp-log.h"

#ifdef NDEBUG
#undef NDEBUG
#endif

#define RX_BUFFER_DATA	0x100 + 4 + 4

#include <assert.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/* Hack: Needs to be in sync with astlpc.c */
struct mctp_binding_astlpc {
	struct mctp_binding	binding;

	union {
		void			*lpc_map;
		struct mctp_lpcmap_hdr	*lpc_hdr;
	};

	/* direct ops data */
	struct mctp_binding_astlpc_ops	ops;
	void			*ops_data;
	struct mctp_lpcmap_hdr	*priv_hdr;

	/* fileio ops data */
	void			*lpc_map_base;
	int			kcs_fd;
	uint8_t			kcs_status;

	bool			running;

	/* temporary transmit buffer */
	uint8_t			txbuf[256];
};

#define KCS_STATUS_BMC_READY		0x80
#define KCS_STATUS_CHANNEL_ACTIVE	0x40
#define KCS_STATUS_IBF			0x02
#define KCS_STATUS_OBF			0x01

struct mctp_binding_astlpc_mmio {
	struct mctp_binding_astlpc astlpc;

	uint8_t kcs[2];

	size_t lpc_size;
	uint8_t *lpc;
};

#ifndef container_of
#define container_of(ptr, type, member) \
	(type *)((char *)(ptr) - (char *)&((type *)0)->member)
#endif

#define binding_to_mmio(b) \
	container_of(b, struct mctp_binding_astlpc_mmio, astlpc)

int mctp_astlpc_mmio_kcs_read(void *data, enum mctp_binding_astlpc_kcs_reg reg,
		uint8_t *val)
{
	struct mctp_binding_astlpc_mmio *mmio = binding_to_mmio(data);

	*val = mmio->kcs[reg];

	mctp_prdebug("%s: 0x%hhx from %s", __func__, *val, reg ? "status" : "data");

	if (reg == MCTP_ASTLPC_KCS_REG_DATA)
		mmio->kcs[MCTP_ASTLPC_KCS_REG_STATUS] &= ~KCS_STATUS_IBF;

	return 0;
}

int mctp_astlpc_mmio_kcs_write(void *data, enum mctp_binding_astlpc_kcs_reg reg,
		uint8_t val)
{
	struct mctp_binding_astlpc_mmio *mmio = binding_to_mmio(data);

	if (reg == MCTP_ASTLPC_KCS_REG_DATA)
		mmio->kcs[MCTP_ASTLPC_KCS_REG_STATUS] |= KCS_STATUS_OBF;

	if (reg == MCTP_ASTLPC_KCS_REG_STATUS)
		mmio->kcs[reg] = val & ~0xaU;
	else
		mmio->kcs[reg] = val;

	mctp_prdebug("%s: 0x%hhx to %s", __func__, val, reg ? "status" : "data");

	return 0;
}
int mctp_astlpc_mmio_lpc_read(void *data, void *buf, off_t offset, size_t len)
{
	struct mctp_binding_astlpc_mmio *mmio = binding_to_mmio(data);

	assert(offset + len < mmio->lpc_size);

	memcpy(buf, mmio->lpc + offset, len);

	mctp_prdebug("%s: %zu bytes from 0x%zx", __func__, len, offset);

	return 0;
}

int mctp_astlpc_mmio_lpc_write(void *data, void *buf, off_t offset, size_t len)
{
	struct mctp_binding_astlpc_mmio *mmio = binding_to_mmio(data);

	assert(offset + len < mmio->lpc_size);

	memcpy(mmio->lpc + offset, buf, len);

	mctp_prdebug("%s: %zu bytes to 0x%zx", __func__, len, offset);

	return 0;
}

static void rx_message(uint8_t eid, void *data, void *msg, size_t len)
{
	uint8_t type;

	type = *(uint8_t *)msg;

	mctp_prdebug("MCTP message received: len %zd, type %d",
			len, type);
}

const struct mctp_binding_astlpc_ops mctp_binding_astlpc_mmio_ops = {
	.kcs_read = mctp_astlpc_mmio_kcs_read,
	.kcs_write = mctp_astlpc_mmio_kcs_write,
	.lpc_read = mctp_astlpc_mmio_lpc_read,
	.lpc_write = mctp_astlpc_mmio_lpc_write,
};

int main(void)
{
	struct mctp_binding_astlpc_mmio mmio;
	struct mctp_binding_astlpc *astlpc;
	uint8_t msg[2 * MCTP_BTU];
	struct mctp *mctp;
	int rc;

	memset(&msg[0], 0x5a, MCTP_BTU);
	memset(&msg[MCTP_BTU], 0xa5, MCTP_BTU);

	mmio.lpc_size = 1 * 1024 * 1024;
	mmio.lpc = calloc(1, mmio.lpc_size);

	mctp_set_log_stdio(MCTP_LOG_DEBUG);

	mctp = mctp_init();
	assert(mctp);

	mctp_set_rx_all(mctp, rx_message, NULL);

	astlpc = mctp_astlpc_init_ops(&mctp_binding_astlpc_mmio_ops, &mmio, NULL);

	mctp_register_bus(mctp, &astlpc->binding, 8);

	/* Verify the binding was initialised */
	assert(mmio.kcs[MCTP_ASTLPC_KCS_REG_STATUS] & KCS_STATUS_BMC_READY);
	
	/* Host sends channel init command */
	mmio.kcs[MCTP_ASTLPC_KCS_REG_STATUS] |= KCS_STATUS_IBF;
	mmio.kcs[MCTP_ASTLPC_KCS_REG_DATA] = 0x00;

	/* Receive host init */
	mctp_astlpc_poll(astlpc);

	/* Host receives init response */
	assert(mmio.kcs[MCTP_ASTLPC_KCS_REG_STATUS] & KCS_STATUS_OBF);
	assert(mmio.kcs[MCTP_ASTLPC_KCS_REG_STATUS] & KCS_STATUS_CHANNEL_ACTIVE);

	/* Host dequeues data */
	assert(mmio.kcs[MCTP_ASTLPC_KCS_REG_DATA] == 0xff);
	mmio.kcs[MCTP_ASTLPC_KCS_REG_STATUS] &= ~KCS_STATUS_OBF;

	/* BMC sends a message */
	rc = mctp_message_tx(mctp, 9, msg, sizeof(msg));
	assert(rc == 0);

	/* Host receives a message */
	assert(mmio.kcs[MCTP_ASTLPC_KCS_REG_STATUS] & KCS_STATUS_OBF);
	assert(mmio.kcs[MCTP_ASTLPC_KCS_REG_DATA] == 0x01);

	/* Verify it's the packet we expect */
	assert(!memcmp(mmio.lpc + RX_BUFFER_DATA, &msg[0], MCTP_BTU));

	/* Host returns Rx area ownership to BMC */
	mmio.kcs[MCTP_ASTLPC_KCS_REG_STATUS] &= ~KCS_STATUS_OBF;
	mmio.kcs[MCTP_ASTLPC_KCS_REG_DATA] = 0x02;
	mmio.kcs[MCTP_ASTLPC_KCS_REG_STATUS] |= KCS_STATUS_IBF;

	/* BMC dequeues ownership hand-over and sends the queued packet */
	rc = mctp_astlpc_poll(astlpc);
	assert(rc == 0);

	/* Host receives a message */
	assert(mmio.kcs[MCTP_ASTLPC_KCS_REG_STATUS] & KCS_STATUS_OBF);
	assert(mmio.kcs[MCTP_ASTLPC_KCS_REG_DATA] == 0x01);

	/* Verify it's the packet we expect */
	assert(!memcmp(mmio.lpc + RX_BUFFER_DATA, &msg[MCTP_BTU], MCTP_BTU));

	return 0;
}