alauda.c

LINUX下USB驱动程序的开发

error:
	kfree(lba_to_pba);
	kfree(pba_to_lba);
out:
	return result;
}

/*
 * Checks to see whether we have already mapped a certain zone
 * If we haven't, the map is generated
 */
static void alauda_ensure_map_for_zone(struct us_data *us, unsigned int zone)
{
	if (MEDIA_INFO(us).lba_to_pba[zone] == NULL
		|| MEDIA_INFO(us).pba_to_lba[zone] == NULL)
		alauda_read_map(us, zone);
}

/*
 * Erases an entire block
 */
static int alauda_erase_block(struct us_data *us, u16 pba)
{
	int rc;
	unsigned char command[] = {
		ALAUDA_BULK_CMD, ALAUDA_BULK_ERASE_BLOCK, PBA_HI(pba),
		PBA_ZONE(pba), 0, PBA_LO(pba), 0x02, 0, MEDIA_PORT(us)
	};
	unsigned char buf[2];

	US_DEBUGP("alauda_erase_block: Erasing PBA %d\n", pba);

	rc = usb_stor_bulk_transfer_buf(us, us->send_bulk_pipe,
		command, 9, NULL);
	if (rc != USB_STOR_XFER_GOOD)
		return rc;

	rc = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
		buf, 2, NULL);
	if (rc != USB_STOR_XFER_GOOD)
		return rc;

	US_DEBUGP("alauda_erase_block: Erase result: %02X %02X\n",
		buf[0], buf[1]);
	return rc;
}

/*
 * Reads data from a certain offset page inside a PBA, including interleaved
 * redundancy data. Returns (pagesize+64)*pages bytes in data.
 */
static int alauda_read_block_raw(struct us_data *us, u16 pba,
		unsigned int page, unsigned int pages, unsigned char *data)
{
	int rc;
	unsigned char command[] = {
		ALAUDA_BULK_CMD, ALAUDA_BULK_READ_BLOCK, PBA_HI(pba),
		PBA_ZONE(pba), 0, PBA_LO(pba) + page, pages, 0, MEDIA_PORT(us)
	};

	US_DEBUGP("alauda_read_block: pba %d page %d count %d\n",
		pba, page, pages);

	rc = usb_stor_bulk_transfer_buf(us, us->send_bulk_pipe,
		command, 9, NULL);
	if (rc != USB_STOR_XFER_GOOD)
		return rc;

	return usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
		data, (MEDIA_INFO(us).pagesize + 64) * pages, NULL);
}

/*
 * Reads data from a certain offset page inside a PBA, excluding redundancy
 * data. Returns pagesize*pages bytes in data. Note that data must be big enough
 * to hold (pagesize+64)*pages bytes of data, but you can ignore those 'extra'
 * trailing bytes outside this function.
 */
static int alauda_read_block(struct us_data *us, u16 pba,
		unsigned int page, unsigned int pages, unsigned char *data)
{
	int i, rc;
	unsigned int pagesize = MEDIA_INFO(us).pagesize;

	rc = alauda_read_block_raw(us, pba, page, pages, data);
	if (rc != USB_STOR_XFER_GOOD)
		return rc;

	/* Cut out the redundancy data */
	for (i = 0; i < pages; i++) {
		int dest_offset = i * pagesize;
		int src_offset = i * (pagesize + 64);
		memmove(data + dest_offset, data + src_offset, pagesize);
	}

	return rc;
}

/*
 * Writes an entire block of data and checks status after write.
 * Redundancy data must be already included in data. Data should be
 * (pagesize+64)*blocksize bytes in length.
 */
static int alauda_write_block(struct us_data *us, u16 pba, unsigned char *data)
{
	int rc;
	struct alauda_info *info = (struct alauda_info *) us->extra;
	unsigned char command[] = {
		ALAUDA_BULK_CMD, ALAUDA_BULK_WRITE_BLOCK, PBA_HI(pba),
		PBA_ZONE(pba), 0, PBA_LO(pba), 32, 0, MEDIA_PORT(us)
	};

	US_DEBUGP("alauda_write_block: pba %d\n", pba);

	rc = usb_stor_bulk_transfer_buf(us, us->send_bulk_pipe,
		command, 9, NULL);
	if (rc != USB_STOR_XFER_GOOD)
		return rc;

	rc = usb_stor_bulk_transfer_buf(us, info->wr_ep, data,
		(MEDIA_INFO(us).pagesize + 64) * MEDIA_INFO(us).blocksize,
		NULL);
	if (rc != USB_STOR_XFER_GOOD)
		return rc;

	return alauda_check_status2(us);
}

/*
 * Write some data to a specific LBA.
 */
static int alauda_write_lba(struct us_data *us, u16 lba,
		 unsigned int page, unsigned int pages,
		 unsigned char *ptr, unsigned char *blockbuffer)
{
	u16 pba, lbap, new_pba;
	unsigned char *bptr, *cptr, *xptr;
	unsigned char ecc[3];
	int i, result;
	unsigned int uzonesize = MEDIA_INFO(us).uzonesize;
	unsigned int zonesize = MEDIA_INFO(us).zonesize;
	unsigned int pagesize = MEDIA_INFO(us).pagesize;
	unsigned int blocksize = MEDIA_INFO(us).blocksize;
	unsigned int lba_offset = lba % uzonesize;
	unsigned int new_pba_offset;
	unsigned int zone = lba / uzonesize;

	alauda_ensure_map_for_zone(us, zone);

	pba = MEDIA_INFO(us).lba_to_pba[zone][lba_offset];
	if (pba == 1) {
		/* Maybe it is impossible to write to PBA 1.
		   Fake success, but don't do anything. */
		printk("alauda_write_lba: avoid writing to pba 1\n");
		return USB_STOR_TRANSPORT_GOOD;
	}

	new_pba = alauda_find_unused_pba(&MEDIA_INFO(us), zone);
	if (!new_pba) {
		printk("alauda_write_lba: Out of unused blocks\n");
		return USB_STOR_TRANSPORT_ERROR;
	}

	/* read old contents */
	if (pba != UNDEF) {
		result = alauda_read_block_raw(us, pba, 0,
			blocksize, blockbuffer);
		if (result != USB_STOR_XFER_GOOD)
			return result;
	} else {
		memset(blockbuffer, 0, blocksize * (pagesize + 64));
	}

	lbap = (lba_offset << 1) | 0x1000;
	if (parity[MSB_of(lbap) ^ LSB_of(lbap)])
		lbap ^= 1;

	/* check old contents and fill lba */
	for (i = 0; i < blocksize; i++) {
		bptr = blockbuffer + (i * (pagesize + 64));
		cptr = bptr + pagesize;
		nand_compute_ecc(bptr, ecc);
		if (!nand_compare_ecc(cptr+13, ecc)) {
			US_DEBUGP("Warning: bad ecc in page %d- of pba %d\n",
				  i, pba);
			nand_store_ecc(cptr+13, ecc);
		}
		nand_compute_ecc(bptr + (pagesize / 2), ecc);
		if (!nand_compare_ecc(cptr+8, ecc)) {
			US_DEBUGP("Warning: bad ecc in page %d+ of pba %d\n",
				  i, pba);
			nand_store_ecc(cptr+8, ecc);
		}
		cptr[6] = cptr[11] = MSB_of(lbap);
		cptr[7] = cptr[12] = LSB_of(lbap);
	}

	/* copy in new stuff and compute ECC */
	xptr = ptr;
	for (i = page; i < page+pages; i++) {
		bptr = blockbuffer + (i * (pagesize + 64));
		cptr = bptr + pagesize;
		memcpy(bptr, xptr, pagesize);
		xptr += pagesize;
		nand_compute_ecc(bptr, ecc);
		nand_store_ecc(cptr+13, ecc);
		nand_compute_ecc(bptr + (pagesize / 2), ecc);
		nand_store_ecc(cptr+8, ecc);
	}

	result = alauda_write_block(us, new_pba, blockbuffer);
	if (result != USB_STOR_XFER_GOOD)
		return result;

	new_pba_offset = new_pba - (zone * zonesize);
	MEDIA_INFO(us).pba_to_lba[zone][new_pba_offset] = lba;
	MEDIA_INFO(us).lba_to_pba[zone][lba_offset] = new_pba;
	US_DEBUGP("alauda_write_lba: Remapped LBA %d to PBA %d\n",
		lba, new_pba);

	if (pba != UNDEF) {
		unsigned int pba_offset = pba - (zone * zonesize);
		result = alauda_erase_block(us, pba);
		if (result != USB_STOR_XFER_GOOD)
			return result;
		MEDIA_INFO(us).pba_to_lba[zone][pba_offset] = UNDEF;
	}

	return USB_STOR_TRANSPORT_GOOD;
}

/*
 * Read data from a specific sector address
 */
static int alauda_read_data(struct us_data *us, unsigned long address,
		unsigned int sectors)
{
	unsigned char *buffer;
	u16 lba, max_lba;
	unsigned int page, len, index, offset;
	unsigned int blockshift = MEDIA_INFO(us).blockshift;
	unsigned int pageshift = MEDIA_INFO(us).pageshift;
	unsigned int blocksize = MEDIA_INFO(us).blocksize;
	unsigned int pagesize = MEDIA_INFO(us).pagesize;
	unsigned int uzonesize = MEDIA_INFO(us).uzonesize;
	int result;

	/*
	 * Since we only read in one block at a time, we have to create
	 * a bounce buffer and move the data a piece at a time between the
	 * bounce buffer and the actual transfer buffer.
	 * We make this buffer big enough to hold temporary redundancy data,
	 * which we use when reading the data blocks.
	 */

	len = min(sectors, blocksize) * (pagesize + 64);
	buffer = kmalloc(len, GFP_NOIO);
	if (buffer == NULL) {
		printk("alauda_read_data: Out of memory\n");
		return USB_STOR_TRANSPORT_ERROR;
	}

	/* Figure out the initial LBA and page */
	lba = address >> blockshift;
	page = (address & MEDIA_INFO(us).blockmask);
	max_lba = MEDIA_INFO(us).capacity >> (blockshift + pageshift);

	result = USB_STOR_TRANSPORT_GOOD;
	index = offset = 0;

	while (sectors > 0) {
		unsigned int zone = lba / uzonesize; /* integer division */
		unsigned int lba_offset = lba - (zone * uzonesize);
		unsigned int pages;
		u16 pba;
		alauda_ensure_map_for_zone(us, zone);

		/* Not overflowing capacity? */
		if (lba >= max_lba) {
			US_DEBUGP("Error: Requested lba %u exceeds "
				  "maximum %u\n", lba, max_lba);
			result = USB_STOR_TRANSPORT_ERROR;
			break;
		}

		/* Find number of pages we can read in this block */
		pages = min(sectors, blocksize - page);
		len = pages << pageshift;

		/* Find where this lba lives on disk */
		pba = MEDIA_INFO(us).lba_to_pba[zone][lba_offset];

		if (pba == UNDEF) {	/* this lba was never written */
			US_DEBUGP("Read %d zero pages (LBA %d) page %d\n",
				  pages, lba, page);

			/* This is not really an error. It just means
			   that the block has never been written.
			   Instead of returning USB_STOR_TRANSPORT_ERROR
			   it is better to return all zero data. */

			memset(buffer, 0, len);
		} else {
			US_DEBUGP("Read %d pages, from PBA %d"
				  " (LBA %d) page %d\n",
				  pages, pba, lba, page);

			result = alauda_read_block(us, pba, page, pages, buffer);
			if (result != USB_STOR_TRANSPORT_GOOD)
				break;
		}

		/* Store the data in the transfer buffer */
		usb_stor_access_xfer_buf(buffer, len, us->srb,
				&index, &offset, TO_XFER_BUF);

		page = 0;
		lba++;
		sectors -= pages;
	}

	kfree(buffer);
	return result;
}

/*
 * Write data to a specific sector address
 */
static int alauda_write_data(struct us_data *us, unsigned long address,
		unsigned int sectors)
{
	unsigned char *buffer, *blockbuffer;
	unsigned int page, len, index, offset;
	unsigned int blockshift = MEDIA_INFO(us).blockshift;
	unsigned int pageshift = MEDIA_INFO(us).pageshift;
	unsigned int blocksize = MEDIA_INFO(us).blocksize;
	unsigned int pagesize = MEDIA_INFO(us).pagesize;
	u16 lba, max_lba;
	int result;

	/*
	 * Since we don't write the user data directly to the device,
	 * we have to create a bounce buffer and move the data a piece
	 * at a time between the bounce buffer and the actual transfer buffer.
	 */

	len = min(sectors, blocksize) * pagesize;
	buffer = kmalloc(len, GFP_NOIO);
	if (buffer == NULL) {
		printk("alauda_write_data: Out of memory\n");
		return USB_STOR_TRANSPORT_ERROR;
	}

	/*
	 * We also need a temporary block buffer, where we read in the old data,
	 * overwrite parts with the new data, and manipulate the redundancy data
	 */
	blockbuffer = kmalloc((pagesize + 64) * blocksize, GFP_NOIO);
	if (blockbuffer == NULL) {
		printk("alauda_write_data: Out of memory\n");
		kfree(buffer);
		return USB_STOR_TRANSPORT_ERROR;
	}

	/* Figure out the initial LBA and page */
	lba = address >> blockshift;
	page = (address & MEDIA_INFO(us).blockmask);
	max_lba = MEDIA_INFO(us).capacity >> (pageshift + blockshift);

	result = USB_STOR_TRANSPORT_GOOD;
	index = offset = 0;

	while (sectors > 0) {
		/* Write as many sectors as possible in this block */
		unsigned int pages = min(sectors, blocksize - page);
		len = pages << pageshift;

		/* Not overflowing capacity? */
		if (lba >= max_lba) {
			US_DEBUGP("alauda_write_data: Requested lba %u exceeds "
				  "maximum %u\n", lba, max_lba);
			result = USB_STOR_TRANSPORT_ERROR;
			break;
		}

		/* Get the data from the transfer buffer */
		usb_stor_access_xfer_buf(buffer, len, us->srb,
				&index, &offset, FROM_XFER_BUF);

		result = alauda_write_lba(us, lba, page, pages, buffer,
			blockbuffer);
		if (result != USB_STOR_TRANSPORT_GOOD)
			break;

		page = 0;
		lba++;
		sectors -= pages;
	}

	kfree(buffer);
	kfree(blockbuffer);
	return result;
}

/*
 * Our interface with the rest of the world
 */

static void alauda_info_destructor(void *extra)
{
	struct alauda_info *info = (struct alauda_info *) extra;
	int port;

	if (!info)
		return;

	for (port = 0; port < 2; port++) {
		struct alauda_media_info *media_info = &info->port[port];

		alauda_free_maps(media_info);
		kfree(media_info->lba_to_pba);
		kfree(media_info->pba_to_lba);
	}
}

/*
 * Initialize alauda_info struct and find the data-write endpoint
 */
int init_alauda(struct us_data *us)
{
	struct alauda_info *info;
	struct usb_host_interface *altsetting = us->pusb_intf->cur_altsetting;
	nand_init_ecc();

	us->extra = kzalloc(sizeof(struct alauda_info), GFP_NOIO);
	if (!us->extra) {
		US_DEBUGP("init_alauda: Gah! Can't allocate storage for"
			"alauda info struct!\n");
		return USB_STOR_TRANSPORT_ERROR;
	}
	info = (struct alauda_info *) us->extra;
	us->extra_destructor = alauda_info_destructor;

	info->wr_ep = usb_sndbulkpipe(us->pusb_dev,
		altsetting->endpoint[0].desc.bEndpointAddress
		& USB_ENDPOINT_NUMBER_MASK);

	return USB_STOR_TRANSPORT_GOOD;
}

int alauda_transport(struct scsi_cmnd *srb, struct us_data *us)
{
	int rc;
	struct alauda_info *info = (struct alauda_info *) us->extra;
	unsigned char *ptr = us->iobuf;
	static unsigned char inquiry_response[36] = {
		0x00, 0x80, 0x00, 0x01, 0x1F, 0x00, 0x00, 0x00
	};

	if (srb->cmnd[0] == INQUIRY) {
		US_DEBUGP("alauda_transport: INQUIRY. "
			"Returning bogus response.\n");
		memcpy(ptr, inquiry_response, sizeof(inquiry_response));
		fill_inquiry_response(us, ptr, 36);
		return USB_STOR_TRANSPORT_GOOD;
	}

	if (srb->cmnd[0] == TEST_UNIT_READY) {
		US_DEBUGP("alauda_transport: TEST_UNIT_READY.\n");
		return alauda_check_media(us);
	}

	if (srb->cmnd[0] == READ_CAPACITY) {
		unsigned int num_zones;
		unsigned long capacity;

		rc = alauda_check_media(us);
		if (rc != USB_STOR_TRANSPORT_GOOD)
			return rc;

		num_zones = MEDIA_INFO(us).capacity >> (MEDIA_INFO(us).zoneshift
			+ MEDIA_INFO(us).blockshift + MEDIA_INFO(us).pageshift);

		capacity = num_zones * MEDIA_INFO(us).uzonesize
			* MEDIA_INFO(us).blocksize;

		/* Report capacity and page size */
		((__be32 *) ptr)[0] = cpu_to_be32(capacity - 1);
		((__be32 *) ptr)[1] = cpu_to_be32(512);

		usb_stor_set_xfer_buf(ptr, 8, srb);
		return USB_STOR_TRANSPORT_GOOD;
	}

	if (srb->cmnd[0] == READ_10) {
		unsigned int page, pages;

		rc = alauda_check_media(us);
		if (rc != USB_STOR_TRANSPORT_GOOD)
			return rc;

		page = short_pack(srb->cmnd[3], srb->cmnd[2]);
		page <<= 16;
		page |= short_pack(srb->cmnd[5], srb->cmnd[4]);
		pages = short_pack(srb->cmnd[8], srb->cmnd[7]);

		US_DEBUGP("alauda_transport: READ_10: page %d pagect %d\n",
			  page, pages);

		return alauda_read_data(us, page, pages);
	}

	if (srb->cmnd[0] == WRITE_10) {
		unsigned int page, pages;

		rc = alauda_check_media(us);
		if (rc != USB_STOR_TRANSPORT_GOOD)
			return rc;

		page = short_pack(srb->cmnd[3], srb->cmnd[2]);
		page <<= 16;
		page |= short_pack(srb->cmnd[5], srb->cmnd[4]);
		pages = short_pack(srb->cmnd[8], srb->cmnd[7]);

		US_DEBUGP("alauda_transport: WRITE_10: page %d pagect %d\n",
			  page, pages);

		return alauda_write_data(us, page, pages);
	}

	if (srb->cmnd[0] == REQUEST_SENSE) {
		US_DEBUGP("alauda_transport: REQUEST_SENSE.\n");

		memset(ptr, 0, 18);
		ptr[0] = 0xF0;
		ptr[2] = info->sense_key;
		ptr[7] = 11;
		ptr[12] = info->sense_asc;
		ptr[13] = info->sense_ascq;
		usb_stor_set_xfer_buf(ptr, 18, srb);

		return USB_STOR_TRANSPORT_GOOD;
	}

	if (srb->cmnd[0] == ALLOW_MEDIUM_REMOVAL) {
		/* sure.  whatever.  not like we can stop the user from popping
		   the media out of the device (no locking doors, etc) */
		return USB_STOR_TRANSPORT_GOOD;
	}

	US_DEBUGP("alauda_transport: Gah! Unknown command: %d (0x%x)\n",
		srb->cmnd[0], srb->cmnd[0]);
	info->sense_key = 0x05;
	info->sense_asc = 0x20;
	info->sense_ascq = 0x00;
	return USB_STOR_TRANSPORT_FAILED;
}