/* This is a sample demonstration application that showcases usage of proxy from the remote core. 
 This application is meant to run on the remote CPU running baremetal.
 This applicationr can print to to master console and perform file I/O using proxy mechanism. */

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <openamp/open_amp.h>
#include <openamp/rpmsg_retarget.h>
#include "platform_info.h"
#include "rpmsg-rpc-demo.h"

#define RPC_BUFF_SIZE 496
#define REDEF_O_CREAT 100
#define REDEF_O_EXCL 200
#define REDEF_O_RDONLY 0
#define REDEF_O_WRONLY 1
#define REDEF_O_RDWR 2
#define REDEF_O_APPEND 2000
#define REDEF_O_ACCMODE 3

#define raw_printf(format, ...) printf(format, ##__VA_ARGS__)
#define LPRINTF(format, ...) raw_printf("Master> " format, ##__VA_ARGS__)
#define LPERROR(format, ...) LPRINTF("ERROR: " format, ##__VA_ARGS__)

static void *platform;
static struct rpmsg_device *rpdev;
static struct rpmsg_endpoint app_ept;
static int request_termination = 0;
static int ept_deleted = 0;
static int err_cnt = 0;

static void *copy_from_shbuf(void *dst, void *shbuf, int len)
{
	void *retdst = dst;

	while (len && ((uintptr_t)shbuf % sizeof(int))) {
		*(uint8_t *)dst = *(uint8_t *)shbuf;
		dst++;
		shbuf++;
		len--;
	}
	while (len >= (int)sizeof(int)) {
		*(unsigned int *)dst = *(unsigned int *)shbuf;
		dst += sizeof(int);
		shbuf += sizeof(int);
		len -= sizeof(int);
	}
	while (len > 0) {
		*(uint8_t *)dst = *(uint8_t *)shbuf;
		dst++;
		shbuf++;
		len--;
	}
	return retdst;
}

static int handle_open(struct rpmsg_rpc_syscall *syscall,
		       struct rpmsg_endpoint *ept)
{
	char *buf;
	struct rpmsg_rpc_syscall resp;
	int fd, ret;

	if (!syscall || !ept)
		return -EINVAL;
	buf = (char *)syscall;
	buf += sizeof(*syscall);

	/* Open remote fd */
	fd = open(buf, syscall->args.int_field1, syscall->args.int_field2);

	/* Construct rpc response */
	resp.id = OPEN_SYSCALL_ID;
	resp.args.int_field1 = fd;
	resp.args.int_field2 = 0;	/*not used */
	resp.args.data_len = 0;	/*not used */

	/* Transmit rpc response */
	ret = rpmsg_send(ept, (void *)&resp, sizeof(resp));

	return ret > 0 ?  0 : ret;
}

static int handle_close(struct rpmsg_rpc_syscall *syscall,
			struct rpmsg_endpoint *ept)
{
	struct rpmsg_rpc_syscall resp;
	int ret;

	if (!syscall || !ept)
		return -EINVAL;
	/* Close remote fd */
	ret = close(syscall->args.int_field1);

	/* Construct rpc response */
	resp.id = CLOSE_SYSCALL_ID;
	resp.args.int_field1 = ret;
	resp.args.int_field2 = 0;	/*not used */
	resp.args.data_len = 0;	/*not used */

	/* Transmit rpc response */
	ret = rpmsg_send(ept, &resp, sizeof(resp));

	return ret > 0 ?  0 : ret;
}

static int handle_read(struct rpmsg_rpc_syscall *syscall,
		       struct rpmsg_endpoint *ept)
{
	struct rpmsg_rpc_syscall *resp;
	unsigned char buf[RPC_BUFF_SIZE];
	unsigned char *payload;
	int bytes_read, payload_size;
	int ret;

	if (!syscall || !ept)
		return -EINVAL;
	payload = buf + sizeof(*resp);
	if (syscall->args.int_field1 == 0) {
		bytes_read = sizeof(buf) - sizeof(*resp);
		/* Perform read from fd for large size since this is a
		   STD/I request */
		bytes_read = read(syscall->args.int_field1, payload,
				  bytes_read);
	} else {
		/* Perform read from fd */
		bytes_read = read(syscall->args.int_field1, payload,
				  syscall->args.int_field2);
	}

	/* Construct rpc response */
	resp = (struct rpmsg_rpc_syscall *)buf;
	resp->id = READ_SYSCALL_ID;
	resp->args.int_field1 = bytes_read;
	resp->args.int_field2 = 0;	/* not used */
	resp->args.data_len = bytes_read;

	payload_size = sizeof(*resp) +
		       ((bytes_read > 0) ? bytes_read : 0);

	/* Transmit rpc response */
	ret = rpmsg_send(ept, buf, payload_size);

	return ret > 0 ?  0 : ret;
}

static int handle_write(struct rpmsg_rpc_syscall *syscall,
			struct rpmsg_endpoint *ept)
{
	struct rpmsg_rpc_syscall resp;
	unsigned char *buf;
	int bytes_written;
	int ret;

	if (!syscall || !ept)
		return -EINVAL;
	buf = (unsigned char *)syscall;
	buf += sizeof(*syscall);
	/* Write to remote fd */
	bytes_written = write(syscall->args.int_field1, buf,
			      syscall->args.int_field2);

	/* Construct rpc response */
	resp.id = WRITE_SYSCALL_ID;
	resp.args.int_field1 = bytes_written;
	resp.args.int_field2 = 0;	/*not used */
	resp.args.data_len = 0;	/*not used */

	/* Transmit rpc response */
	ret = rpmsg_send(ept, (void *)&resp, sizeof(resp));

	return ret > 0 ?  0 : ret;
}

static int handle_rpc(struct rpmsg_rpc_syscall *syscall,
		      struct rpmsg_endpoint *ept)
{
	int retval;

	/* Handle RPC */
	switch (syscall->id) {
	case OPEN_SYSCALL_ID:
		{
			retval = handle_open(syscall, ept);
			break;
		}
	case CLOSE_SYSCALL_ID:
		{
			retval = handle_close(syscall, ept);
			break;
		}
	case READ_SYSCALL_ID:
		{
			retval = handle_read(syscall, ept);
			break;
		}
	case WRITE_SYSCALL_ID:
		{
			retval = handle_write(syscall, ept);
			break;
		}
	case TERM_SYSCALL_ID:
		{
			LPRINTF("Received termination request\n");
			request_termination = 1;
			retval = 0;
			break;
		}
	default:
		{
			LPERROR
			    ("Invalid RPC sys call ID: %d:%d!\n",
			     (int)syscall->id, (int)WRITE_SYSCALL_ID);
			retval = -1;
			break;
		}
	}

	return retval;
}
static void rpmsg_service_unbind(struct rpmsg_endpoint *ept)
{
	(void)ept;
	rpmsg_destroy_ept(&app_ept);
	LPRINTF("Endpoint is destroyed\n");
	ept_deleted = 1;
}

static int rpmsg_endpoint_cb(struct rpmsg_endpoint *ept, void *data, size_t len,
			      uint32_t src, void *priv)
{
	unsigned char buf[RPC_BUFF_SIZE];
	struct rpmsg_rpc_syscall *syscall;

	(void)priv;
	(void)src;

	if (len < (int)sizeof(*syscall)) {
		LPERROR("Received data is less than the rpc structure: %d\n",
			len);
		err_cnt++;
		return RPMSG_SUCCESS;
	}

	/* In case the shared memory is device memory
	 * E.g. For now, we only use UIO device memory in Linux.
	 */
	if (len > RPC_BUFF_SIZE)
		len = RPC_BUFF_SIZE;
	copy_from_shbuf(buf, data, len);
	syscall = (struct rpmsg_rpc_syscall *)buf;
	if (handle_rpc(syscall, ept)) {
		LPRINTF("\nHandling remote procedure call errors:\n");
		raw_printf("rpc id %d\n", syscall->id);
		raw_printf("rpc int field1 %d\n",
		       syscall->args.int_field1);
		raw_printf("\nrpc int field2 %d\n",
		       syscall->args.int_field2);
		err_cnt++;
	}
	return RPMSG_SUCCESS;
}


void terminate_rpc_app()
{
	LPRINTF("Destroying endpoint.\n");
	if (!ept_deleted)
		rpmsg_destroy_ept(&app_ept);
}

void exit_action_handler(int signum)
{
	(void)signum;
	terminate_rpc_app();
}

void kill_action_handler(int signum)
{
	(void)signum;
	LPRINTF("RPC service killed !!\n");

	terminate_rpc_app();

	if (rpdev)
		platform_release_rpmsg_vdev(rpdev);
	if (platform)
		platform_cleanup(platform);
}

/* Application entry point */
int app(struct rpmsg_device *rdev, void *priv)
{
	int ret = 0;
	struct sigaction exit_action;
	struct sigaction kill_action;

	/* Initialize signalling infrastructure */
	memset(&exit_action, 0, sizeof(struct sigaction));
	memset(&kill_action, 0, sizeof(struct sigaction));
	exit_action.sa_handler = exit_action_handler;
	kill_action.sa_handler = kill_action_handler;
	sigaction(SIGTERM, &exit_action, NULL);
	sigaction(SIGINT, &exit_action, NULL);
	sigaction(SIGKILL, &kill_action, NULL);
	sigaction(SIGHUP, &kill_action, NULL);

	/* Initialize RPMSG framework */
	LPRINTF("Try to create rpmsg endpoint.\n");

	ret = rpmsg_create_ept(&app_ept, rdev, RPMSG_SERVICE_NAME,
			       0, RPMSG_ADDR_ANY, rpmsg_endpoint_cb,
			       rpmsg_service_unbind);
	if (ret) {
		LPERROR("Failed to create endpoint.\n");
		return -EINVAL;
	}

	LPRINTF("Successfully created rpmsg endpoint.\n");
	while(1) {
		platform_poll(priv);
		if (err_cnt) {
			LPERROR("Got error!\n");
			ret = -EINVAL;
			break;
		}
		/* we got a shutdown request, exit */
		if (ept_deleted || request_termination) {
			break;
		}
	}
	LPRINTF("\nRPC service exiting !!\n");

	terminate_rpc_app();
	return ret;
}

int main(int argc, char *argv[])
{
	int ret;

	LPRINTF("Starting application...\n");

	/* Initialize platform */
	ret = platform_init(argc, argv, &platform);
	if (ret) {
		LPERROR("Failed to initialize platform.\n");
		ret = -1;
	} else {
		rpdev = platform_create_rpmsg_vdev(platform, 0,
						   VIRTIO_DEV_MASTER,
						   NULL, NULL);
		if (!rpdev) {
			LPERROR("Failed to create rpmsg virtio device.\n");
			ret = -1;
		} else {
			app(rpdev, platform);
			platform_release_rpmsg_vdev(rpdev);
			ret = 0;
		}
	}

	LPRINTF("Stopping application...\n");
	platform_cleanup(platform);

	return ret;
}