/*
 * Copyright (c) 2009 Jiri Svoboda
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup bd
 * @{
 */

/**
 * @file
 * @brief GXemul disk driver
 */

#include <stdio.h>
#include <libarch/ddi.h>
#include <ddi.h>
#include <ipc/ipc.h>
#include <ipc/bd.h>
#include <async.h>
#include <as.h>
#include <futex.h>
#include <devmap.h>
#include <sys/types.h>
#include <errno.h>

#define NAME "gxe_bd"

enum {
	CTL_READ_START	= 0,
	CTL_WRITE_START = 1,
};

enum {
	STATUS_FAILURE	= 0
};

enum {
	MAX_DISKS	= 2
};

typedef struct {
	uint32_t offset_lo;
	uint32_t pad0;
	uint32_t offset_hi;
	uint32_t pad1;

	uint32_t disk_id;
	uint32_t pad2[3];

	uint32_t control;
	uint32_t pad3[3];

	uint32_t status;

	uint32_t pad4[3];
	uint8_t pad5[0x3fc0];

	uint8_t buffer[512];
} gxe_bd_t;


static const size_t block_size = 512;
static size_t comm_size;

static uintptr_t dev_physical = 0x13000000;
static gxe_bd_t *dev;

static dev_handle_t dev_handle[MAX_DISKS];

static atomic_t dev_futex = FUTEX_INITIALIZER;

static int gxe_bd_init(void);
static void gxe_bd_connection(ipc_callid_t iid, ipc_call_t *icall);
static int gx_bd_rdwr(int disk_id, ipcarg_t method, off_t offset, off_t size,
    void *buf);
static int gxe_bd_read_block(int disk_id, uint64_t offset, size_t size,
    void *buf);
static int gxe_bd_write_block(int disk_id, uint64_t offset, size_t size,
    const void *buf);

int main(int argc, char **argv)
{
	printf(NAME ": GXemul disk driver\n");

	if (gxe_bd_init() != EOK)
		return -1;

	printf(NAME ": Accepting connections\n");
	async_manager();

	/* Not reached */
	return 0;
}

static int gxe_bd_init(void)
{
	void *vaddr;
	int rc, i;
	char name[16];

	rc = devmap_driver_register(NAME, gxe_bd_connection);
	if (rc < 0) {
		printf(NAME ": Unable to register driver.\n");
		return rc;
	}

	rc = pio_enable((void *) dev_physical, sizeof(gxe_bd_t), &vaddr);
	if (rc != EOK) {
		printf(NAME ": Could not initialize device I/O space.\n");
		return rc;
	}

	dev = vaddr;

	for (i = 0; i < MAX_DISKS; i++) {
		snprintf(name, 16, "disk%d", i);
		rc = devmap_device_register(name, &dev_handle[i]);
		if (rc != EOK) {
			devmap_hangup_phone(DEVMAP_DRIVER);
			printf(NAME ": Unable to register device %s.\n",
				name);
			return rc;
		}
	}

	return EOK;
}

static void gxe_bd_connection(ipc_callid_t iid, ipc_call_t *icall)
{
	void *fs_va = NULL;
	ipc_callid_t callid;
	ipc_call_t call;
	ipcarg_t method;
	dev_handle_t dh;
	int flags;
	int retval;
	off_t idx;
	off_t size;
	int disk_id, i;

	/* Get the device handle. */
	dh = IPC_GET_ARG1(*icall);

	/* Determine which disk device is the client connecting to. */
	disk_id = -1;
	for (i = 0; i < MAX_DISKS; i++)
		if (dev_handle[i] == dh)
			disk_id = i;

	if (disk_id < 0) {
		ipc_answer_0(iid, EINVAL);
		return;
	}

	/* Answer the IPC_M_CONNECT_ME_TO call. */
	ipc_answer_0(iid, EOK);

	if (!ipc_share_out_receive(&callid, &comm_size, &flags)) {
		ipc_answer_0(callid, EHANGUP);
		return;
	}

	fs_va = as_get_mappable_page(comm_size);
	if (fs_va == NULL) {
		ipc_answer_0(callid, EHANGUP);
		return;
	}

	(void) ipc_share_out_finalize(callid, fs_va);

	while (1) {
		callid = async_get_call(&call);
		method = IPC_GET_METHOD(call);
		switch (method) {
		case IPC_M_PHONE_HUNGUP:
			/* The other side has hung up. */
			ipc_answer_0(callid, EOK);
			return;
		case BD_READ_BLOCK:
		case BD_WRITE_BLOCK:
			idx = IPC_GET_ARG1(call);
			size = IPC_GET_ARG2(call);
			if (size > comm_size) {
				retval = EINVAL;
				break;
			}
			retval = gx_bd_rdwr(disk_id, method, idx * size,
			    size, fs_va);
			break;
		default:
			retval = EINVAL;
			break;
		}
		ipc_answer_0(callid, retval);
	}
}

static int gx_bd_rdwr(int disk_id, ipcarg_t method, off_t offset, off_t size,
    void *buf)
{
	int rc;
	size_t now;

	while (size > 0) {
		now = size < block_size ? size : block_size;

		if (method == BD_READ_BLOCK)
			rc = gxe_bd_read_block(disk_id, offset, now, buf);
		else
			rc = gxe_bd_write_block(disk_id, offset, now, buf);

		if (rc != EOK)
			return rc;

		buf += block_size;
		offset += block_size;

		if (size > block_size)
			size -= block_size;
		else
			size = 0;
	}

	return EOK;
}

static int gxe_bd_read_block(int disk_id, uint64_t offset, size_t size,
    void *buf)
{
	uint32_t status;
	size_t i;
	uint32_t w;

	futex_down(&dev_futex);
	pio_write_32(&dev->offset_lo, (uint32_t) offset);
	pio_write_32(&dev->offset_hi, offset >> 32);
	pio_write_32(&dev->disk_id, disk_id);
	pio_write_32(&dev->control, CTL_READ_START);

	status = pio_read_32(&dev->status);
	if (status == STATUS_FAILURE) {
		return EIO;
	}

	for (i = 0; i < size; i++) {
		((uint8_t *) buf)[i] = w = pio_read_8(&dev->buffer[i]);
	}

	futex_up(&dev_futex);
	return EOK;
}

static int gxe_bd_write_block(int disk_id, uint64_t offset, size_t size,
    const void *buf)
{
	uint32_t status;
	size_t i;

	for (i = 0; i < size; i++) {
		pio_write_8(&dev->buffer[i], ((const uint8_t *) buf)[i]);
	}

	futex_down(&dev_futex);
	pio_write_32(&dev->offset_lo, (uint32_t) offset);
	pio_write_32(&dev->offset_hi, offset >> 32);
	pio_write_32(&dev->disk_id, disk_id);
	pio_write_32(&dev->control, CTL_WRITE_START);

	status = pio_read_32(&dev->status);
	if (status == STATUS_FAILURE) {
		return EIO;
	}

	futex_up(&dev_futex);
	return EOK;
}

/**
 * @}
 */