// ramdisk.c
// Author: Josh Holtrop
// Date: 08/20/04
// Modified: 08/22/04

#include "block/ramdisk.h"
#include "fs/devices.h"
#include "functions.h"
#include "mm/vmm.h"
#include "lang/asmfuncs.h"

ramdisk_t *ramdisks[256];

int	ramdisk_init(major_t major)
{
	dev_driver_t *ramdisk_driver;
	if (( ramdisk_driver = New(dev_driver_t) ))
	{
		ramdisk_driver->block_read = ramdisk_block_read;
		ramdisk_driver->block_write = ramdisk_block_write;
		devices_register_major('b', major, ramdisk_driver);
		return 0;
	}
	return -1;
}

minor_t ramdisk_new(u32_t size)
{
	int i;
	for (i = 0; i < 256; i++)
	{
		if (!ramdisks[i])
		{
			void *start;
			if (( start = kmalloc(size) ))
			{
				ramdisks[i] = New(ramdisk_t);
				ramdisks[i]->start = start;
				ramdisks[i]->size = size;
				return i;
			}
			return -2;
		}
	}
	return -1;
}

minor_t	ramdisk_register(void *ramdisk, u32_t size)
{
	int i;
	for (i = 0; i < 256; i++)
	{
		if (!ramdisks[i])
		{
		  ramdisks[i] = New(ramdisk_t);
			ramdisks[i]->start = ramdisk;
			ramdisks[i]->size = size;
			return i;
		}
	}
	return -1;
}

int	ramdisk_remove(minor_t minor)
{
	if (ramdisks[minor])
	{
		kfree(ramdisks[minor]->start);
		kfree(ramdisks[minor]);
		ramdisks[minor] = NULL;
		return 0;
	}
	return -1;
}

int	ramdisk_block_read(minor_t minor, u32_t blockNum, u32_t count, void *buffer)
{
	if (!ramdisks[minor])
		return -1;
	if ((blockNum << BLOCK_SIZE_LOG) >= ramdisks[minor]->size)
		return -2;
	void *rdAddr = ramdisks[minor]->start + (blockNum << BLOCK_SIZE_LOG);
	u32_t copyLen = min(count << BLOCK_SIZE_LOG, ramdisks[minor]->size - (u32_t)rdAddr);
	memcpyd(buffer, rdAddr, copyLen >> 2);
	return copyLen;
}

int	ramdisk_block_write(minor_t minor, u32_t blockNum, u32_t count, void *buffer)
{
	if (!ramdisks[minor])
		return -1;
	if ((blockNum << BLOCK_SIZE_LOG) >= ramdisks[minor]->size)
		return -2;
	void *rdAddr = ramdisks[minor]->start + (blockNum << BLOCK_SIZE_LOG);
	u32_t copyLen = min(count << BLOCK_SIZE_LOG, ramdisks[minor]->size - (u32_t)rdAddr);
	memcpyd(rdAddr, buffer, copyLen >> 2);
	return copyLen;
}