path: root/drivers/mtd/maps/vmu-flash.c

/* vmu-flash.c
 * Driver for SEGA Dreamcast Visual Memory Unit
 *
 * Copyright (c) Adrian McMenamin 2002 - 2009
 * Copyright (c) Paul Mundt 2001
 *
 * Licensed under version 2 of the
 * GNU General Public Licence
 */
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/maple.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/map.h>

struct vmu_cache {
	unsigned char *buffer;		/* Cache */
	unsigned int block;		/* Which block was cached */
	unsigned long jiffies_atc;	/* When was it cached? */
	int valid;
};

struct mdev_part {
	struct maple_device *mdev;
	int partition;
};

struct vmupart {
	u16 user_blocks;
	u16 root_block;
	u16 numblocks;
	char *name;
	struct vmu_cache *pcache;
};

struct memcard {
	u16 tempA;
	u16 tempB;
	u32 partitions;
	u32 blocklen;
	u32 writecnt;
	u32 readcnt;
	u32 removeable;
	int partition;
	int read;
	unsigned char *blockread;
	struct vmupart *parts;
	struct mtd_info *mtd;
};

struct vmu_block {
	unsigned int num; /* block number */
	unsigned int ofs; /* block offset */
};

static struct vmu_block *ofs_to_block(unsigned long src_ofs,
	struct mtd_info *mtd, int partition)
{
	struct vmu_block *vblock;
	struct maple_device *mdev;
	struct memcard *card;
	struct mdev_part *mpart;
	int num;

	mpart = mtd->priv;
	mdev = mpart->mdev;
	card = maple_get_drvdata(mdev);

	if (src_ofs >= card->parts[partition].numblocks * card->blocklen)
		goto failed;

	num = src_ofs / card->blocklen;
	if (num > card->parts[partition].numblocks)
		goto failed;

	vblock = kmalloc(sizeof(struct vmu_block), GFP_KERNEL);
	if (!vblock)
		goto failed;

	vblock->num = num;
	vblock->ofs = src_ofs % card->blocklen;
	return vblock;

failed:
	return NULL;
}

/* Maple bus callback function for reads */
static void vmu_blockread(struct mapleq *mq)
{
	struct maple_device *mdev;
	struct memcard *card;

	mdev = mq->dev;
	card = maple_get_drvdata(mdev);
	/* copy the read in data */

	if (unlikely(!card->blockread))
		return;

	memcpy(card->blockread, mq->recvbuf->buf + 12,
		card->blocklen/card->readcnt);

}

/* Interface with maple bus to read blocks
 * caching the results so that other parts
 * of the driver can access block reads */
static int maple_vmu_read_block(unsigned int num, unsigned char *buf,
	struct mtd_info *mtd)
{
	struct memcard *card;
	struct mdev_part *mpart;
	struct maple_device *mdev;
	int partition, error = 0, x, wait;
	unsigned char *blockread = NULL;
	struct vmu_cache *pcache;
	__be32 sendbuf;

	mpart = mtd->priv;
	mdev = mpart->mdev;
	partition = mpart->partition;
	card = maple_get_drvdata(mdev);
	pcache = card->parts[partition].pcache;
	pcache->valid = 0;

	/* prepare the cache for this block */
	if (!pcache->buffer) {
		pcache->buffer = kmalloc(card->blocklen, GFP_KERNEL);
		if (!pcache->buffer) {
			dev_err(&mdev->dev, "VMU at (%d, %d) - read fails due"
				" to lack of memory\n", mdev->port,
				mdev->unit);
			error = -ENOMEM;
			goto outB;
		}
	}

	/*
	* Reads may be phased - again the hardware spec
	* supports this - though may not be any devices in
	* the wild that implement it, but we will here
	*/
	for (x = 0; x < card->readcnt; x++) {
		sendbuf = cpu_to_be32(partition << 24 | x << 16 | num);

		if (atomic_read(&mdev->busy) == 1) {
			wait_event_interruptible_timeout(mdev->maple_wait,
				atomic_read(&mdev->busy) == 0, HZ);
			if (atomic_read(&mdev->busy) == 1) {
				dev_notice(&mdev->dev, "VMU at (%d, %d)"
					" is busy\n", mdev->port, mdev->unit);
				error = -EAGAIN;
				goto outB;
			}
		}

		atomic_set(&mdev->busy, 1);
		blockread = kmalloc(card->blocklen/card->readcnt, GFP_KERNEL);
		if (!blockread) {
			error = -ENOMEM;
			atomic_set(&mdev->busy, 0);
			goto outB;
		}
		card->blockread = blockread;

		maple_getcond_callback(mdev, vmu_blockread, 0,
			MAPLE_FUNC_MEMCARD);
		error = maple_add_packet(mdev, MAPLE_FUNC_MEMCARD,
				MAPLE_COMMAND_BREAD, 2, &sendbuf);
		/* Very long timeouts seem to be needed when box is stressed */
		wait = wait_event_interruptible_timeout(mdev->maple_wait,
			(atomic_read(&mdev