mtd_dataflash.c

飞思卡尔芯片imx27下的MTD模块的驱动源码

		spi->dev.bus_id, (unsigned)to, (unsigned)(to + len));

	*retlen = 0;

	/* Sanity checks */
	if (!len)
		return 0;
	if ((to + len) > mtd->size)
		return -EINVAL;

	spi_message_init(&msg);

	x[0].tx_buf = command = priv->command;
	x[0].len = 4;
	spi_message_add_tail(&x[0], &msg);

	pageaddr = ((unsigned)to / priv->page_size);
	offset = ((unsigned)to % priv->page_size);
	if (offset + len > priv->page_size)
		writelen = priv->page_size - offset;
	else
		writelen = len;

	down(&priv->lock);
	while (remaining > 0) {
		DEBUG(MTD_DEBUG_LEVEL3, "write @ %i:%i len=%i\n",
			pageaddr, offset, writelen);

		/* REVISIT:
		 * (a) each page in a sector must be rewritten at least
		 *     once every 10K sibling erase/program operations.
		 * (b) for pages that are already erased, we could
		 *     use WRITE+MWRITE not PROGRAM for ~30% speedup.
		 * (c) WRITE to buffer could be done while waiting for
		 *     a previous MWRITE/MWERASE to complete ...
		 * (d) error handling here seems to be mostly missing.
		 *
		 * Two persistent bits per page, plus a per-sector counter,
		 * could support (a) and (b) ... we might consider using
		 * the second half of sector zero, which is just one block,
		 * to track that state.  (On AT91, that sector should also
		 * support boot-from-DataFlash.)
		 */

		addr = pageaddr << priv->page_offset;

		/* (1) Maybe transfer partial page to Buffer1 */
		if (writelen != priv->page_size) {
			command[0] = OP_TRANSFER_BUF1;
			command[1] = (addr & 0x00FF0000) >> 16;
			command[2] = (addr & 0x0000FF00) >> 8;
			command[3] = 0;

			DEBUG(MTD_DEBUG_LEVEL3, "TRANSFER: (%x) %x %x %x\n",
				command[0], command[1], command[2], command[3]);

			status = spi_sync(spi, &msg);
			if (status < 0)
				DEBUG(MTD_DEBUG_LEVEL1, "%s: xfer %u -> %d \n",
					spi->dev.bus_id, addr, status);

			(void) dataflash_waitready(priv->spi);
		}

		/* (2) Program full page via Buffer1 */
		addr += offset;
		command[0] = OP_PROGRAM_VIA_BUF1;
		command[1] = (addr & 0x00FF0000) >> 16;
		command[2] = (addr & 0x0000FF00) >> 8;
		command[3] = (addr & 0x000000FF);

		DEBUG(MTD_DEBUG_LEVEL3, "PROGRAM: (%x) %x %x %x\n",
			command[0], command[1], command[2], command[3]);

		x[1].tx_buf = writebuf;
		x[1].len = writelen;
		spi_message_add_tail(x + 1, &msg);
		status = spi_sync(spi, &msg);
		spi_transfer_del(x + 1);
		if (status < 0)
			DEBUG(MTD_DEBUG_LEVEL1, "%s: pgm %u/%u -> %d \n",
				spi->dev.bus_id, addr, writelen, status);

		(void) dataflash_waitready(priv->spi);


#ifdef	CONFIG_DATAFLASH_WRITE_VERIFY

		/* (3) Compare to Buffer1 */
		addr = pageaddr << priv->page_offset;
		command[0] = OP_COMPARE_BUF1;
		command[1] = (addr & 0x00FF0000) >> 16;
		command[2] = (addr & 0x0000FF00) >> 8;
		command[3] = 0;

		DEBUG(MTD_DEBUG_LEVEL3, "COMPARE: (%x) %x %x %x\n",
			command[0], command[1], command[2], command[3]);

		status = spi_sync(spi, &msg);
		if (status < 0)
			DEBUG(MTD_DEBUG_LEVEL1, "%s: compare %u -> %d \n",
				spi->dev.bus_id, addr, status);

		status = dataflash_waitready(priv->spi);

		/* Check result of the compare operation */
		if ((status & (1 << 6)) == 1) {
			printk(KERN_ERR "%s: compare page %u, err %d\n",
				spi->dev.bus_id, pageaddr, status);
			remaining = 0;
			status = -EIO;
			break;
		} else
			status = 0;

#endif	/* CONFIG_DATAFLASH_WRITE_VERIFY */

		remaining = remaining - writelen;
		pageaddr++;
		offset = 0;
		writebuf += writelen;
		*retlen += writelen;

		if (remaining > priv->page_size)
			writelen = priv->page_size;
		else
			writelen = remaining;
	}
	up(&priv->lock);

	return status;
}

/* ......................................................................... */

/*
 * Register DataFlash device with MTD subsystem.
 */
static int __devinit
add_dataflash(struct spi_device *spi, char *name,
		int nr_pages, int pagesize, int pageoffset)
{
	struct dataflash		*priv;
	struct mtd_info			*device;
	struct flash_platform_data	*pdata = spi->dev.platform_data;

	priv = (struct dataflash *) kzalloc(sizeof *priv, GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	init_MUTEX(&priv->lock);
	priv->spi = spi;
	priv->page_size = pagesize;
	priv->page_offset = pageoffset;

	/* name must be usable with cmdlinepart */
	sprintf(priv->name, "spi%d.%d-%s",
			spi->master->bus_num, spi->chip_select,
			name);

	device = &priv->mtd;
	device->name = (pdata && pdata->name) ? pdata->name : priv->name;
	device->size = nr_pages * pagesize;
	device->erasesize = pagesize;
	device->writesize = pagesize;
	device->owner = THIS_MODULE;
	device->type = MTD_DATAFLASH;
	device->flags = MTD_CAP_NORFLASH;
	device->erase = dataflash_erase;
	device->read = dataflash_read;
	device->write = dataflash_write;
	device->priv = priv;

	dev_info(&spi->dev, "%s (%d KBytes)\n", name, device->size/1024);
	dev_set_drvdata(&spi->dev, priv);

	if (mtd_has_partitions()) {
		struct mtd_partition	*parts;
		int			nr_parts = 0;

#ifdef CONFIG_MTD_CMDLINE_PARTS
		static const char *part_probes[] = { "cmdlinepart", NULL, };

		nr_parts = parse_mtd_partitions(device, part_probes, &parts, 0);
#endif

		if (nr_parts <= 0 && pdata && pdata->parts) {
			parts = pdata->parts;
			nr_parts = pdata->nr_parts;
		}

		if (nr_parts > 0) {
			priv->partitioned = 1;
			return add_mtd_partitions(device, parts, nr_parts);
		}
	} else if (pdata && pdata->nr_parts)
		dev_warn(&spi->dev, "ignoring %d default partitions on %s\n",
				pdata->nr_parts, device->name);

	return add_mtd_device(device) == 1 ? -ENODEV : 0;
}

/*
 * Detect and initialize DataFlash device:
 *
 *   Device      Density         ID code          #Pages PageSize  Offset
 *   AT45DB011B  1Mbit   (128K)  xx0011xx (0x0c)    512    264      9
 *   AT45DB021B  2Mbit   (256K)  xx0101xx (0x14)   1025    264      9
 *   AT45DB041B  4Mbit   (512K)  xx0111xx (0x1c)   2048    264      9
 *   AT45DB081B  8Mbit   (1M)    xx1001xx (0x24)   4096    264      9
 *   AT45DB0161B 16Mbit  (2M)    xx1011xx (0x2c)   4096    528     10
 *   AT45DB0321B 32Mbit  (4M)    xx1101xx (0x34)   8192    528     10
 *   AT45DB0642  64Mbit  (8M)    xx111xxx (0x3c)   8192   1056     11
 *   AT45DB1282  128Mbit (16M)   xx0100xx (0x10)  16384   1056     11
 */
static int __devinit dataflash_probe(struct spi_device *spi)
{
	int status;

	status = dataflash_status(spi);
	if (status <= 0 || status == 0xff) {
		DEBUG(MTD_DEBUG_LEVEL1, "%s: status error %d\n",
				spi->dev.bus_id, status);
		if (status == 0xff)
			status = -ENODEV;
		return status;
	}

	/* if there's a device there, assume it's dataflash.
	 * board setup should have set spi->max_speed_max to
	 * match f(car) for continuous reads, mode 0 or 3.
	 */
	switch (status & 0x3c) {
	case 0x0c:	/* 0 0 1 1 x x */
		status = add_dataflash(spi, "AT45DB011B", 512, 264, 9);
		break;
	case 0x14:	/* 0 1 0 1 x x */
		status = add_dataflash(spi, "AT45DB021B", 1025, 264, 9);
		break;
	case 0x1c:	/* 0 1 1 1 x x */
		status = add_dataflash(spi, "AT45DB041x", 2048, 264, 9);
		break;
	case 0x24:	/* 1 0 0 1 x x */
		status = add_dataflash(spi, "AT45DB081B", 4096, 264, 9);
		break;
	case 0x2c:	/* 1 0 1 1 x x */
		status = add_dataflash(spi, "AT45DB161x", 4096, 528, 10);
		break;
	case 0x34:	/* 1 1 0 1 x x */
		status = add_dataflash(spi, "AT45DB321x", 8192, 528, 10);
		break;
	case 0x38:	/* 1 1 1 x x x */
	case 0x3c:
		status = add_dataflash(spi, "AT45DB642x", 8192, 1056, 11);
		break;
	/* obsolete AT45DB1282 not (yet?) supported */
	default:
		DEBUG(MTD_DEBUG_LEVEL1, "%s: unsupported device (%x)\n",
				spi->dev.bus_id, status & 0x3c);
		status = -ENODEV;
	}

	if (status < 0)
		DEBUG(MTD_DEBUG_LEVEL1, "%s: add_dataflash --> %d\n",
				spi->dev.bus_id, status);

	return status;
}

static int __devexit dataflash_remove(struct spi_device *spi)
{
	struct dataflash	*flash = dev_get_drvdata(&spi->dev);
	int			status;

	DEBUG(MTD_DEBUG_LEVEL1, "%s: remove\n", spi->dev.bus_id);

	if (mtd_has_partitions() && flash->partitioned)
		status = del_mtd_partitions(&flash->mtd);
	else
		status = del_mtd_device(&flash->mtd);
	if (status == 0)
		kfree(flash);
	return status;
}

static struct spi_driver dataflash_driver = {
	.driver = {
		.name		= "mtd_dataflash",
		.bus		= &spi_bus_type,
		.owner		= THIS_MODULE,
	},

	.probe		= dataflash_probe,
	.remove		= __devexit_p(dataflash_remove),

	/* FIXME:  investigate suspend and resume... */
};

static int __init dataflash_init(void)
{
	return spi_register_driver(&dataflash_driver);
}
module_init(dataflash_init);

static void __exit dataflash_exit(void)
{
	spi_unregister_driver(&dataflash_driver);
}
module_exit(dataflash_exit);


MODULE_LICENSE("GPL");
MODULE_AUTHOR("Andrew Victor, David Brownell");
MODULE_DESCRIPTION("MTD DataFlash driver");