datafab.c

LINUX下USB驱动程序的开发

/* Driver for Datafab USB Compact Flash reader
 *
 * $Id: datafab.c,v 1.7 2002/02/25 00:40:13 mdharm Exp $
 *
 * datafab driver v0.1:
 *
 * First release
 *
 * Current development and maintenance by:
 *   (c) 2000 Jimmie Mayfield ([e-mail])
 *
 *   Many thanks to Robert Baruch for the SanDisk SmartMedia reader driver
 *   which I used as a template for this driver.
 *
 *   Some bugfixes and scatter-gather code by Gregory P. Smith 
 *   ([e-mail])
 *
 *   Fix for media change by Joerg Schneider ([e-mail])
 *
 * Other contributors:
 *   (c) 2002 Alan Stern <[e-mail]>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2, or (at your option) any
 * later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/*
 * This driver attempts to support USB CompactFlash reader/writer devices
 * based on Datafab USB-to-ATA chips.  It was specifically developed for the 
 * Datafab MDCFE-B USB CompactFlash reader but has since been found to work 
 * with a variety of Datafab-based devices from a number of manufacturers.
 * I've received a report of this driver working with a Datafab-based
 * SmartMedia device though please be aware that I'm personally unable to
 * test SmartMedia support.
 *
 * This driver supports reading and writing.  If you're truly paranoid,
 * however, you can force the driver into a write-protected state by setting
 * the WP enable bits in datafab_handle_mode_sense().  Basically this means
 * setting mode_param_header[3] = 0x80.
 */

#include "transport.h"
#include "protocol.h"
#include "usb.h"
#include "debug.h"
#include "datafab.h"

#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/slab.h>

extern int usb_stor_bulk_msg(struct us_data *us, void *data, int pipe,
			     unsigned int len, unsigned int *act_len);

static int datafab_determine_lun(struct us_data *us, struct datafab_info *info);


static void datafab_dump_data(unsigned char *data, int len)
{
	unsigned char buf[80];
	int sofar = 0;

	if (!data)
		return;

	memset(buf, 0, sizeof(buf));

	for (sofar = 0; sofar < len; sofar++) {
		sprintf(buf + strlen(buf), "%02x ",
			((unsigned int) data[sofar]) & 0xFF);

		if (sofar % 16 == 15) {
			US_DEBUGP("datafab:  %s\n", buf);
			memset(buf, 0, sizeof(buf));
		}
	}

	if (strlen(buf) != 0)
		US_DEBUGP("datafab:  %s\n", buf);
}


static int datafab_raw_bulk(int direction,
			    struct us_data *us,
			    unsigned char *data, 
		            unsigned int len)
{
	int result;
	int act_len;
	int pipe;

	if (direction == SCSI_DATA_READ)
		pipe = usb_rcvbulkpipe(us->pusb_dev, us->ep_in);
	else
		pipe = usb_sndbulkpipe(us->pusb_dev, us->ep_out);

	result = usb_stor_bulk_msg(us, data, pipe, len, &act_len);

	// if we stall, we need to clear it before we go on 
	if (result == -EPIPE) {
		US_DEBUGP("datafab_raw_bulk: EPIPE. clearing endpoint halt for"
			  " pipe 0x%x, stalled at %d bytes\n", pipe, act_len);
		usb_stor_clear_halt(us, pipe);
	}

	if (result) {
		// NAK - that means we've retried a few times already 
		if (result == -ETIMEDOUT) {
			US_DEBUGP("datafab_raw_bulk:  device NAKed\n");
			return US_BULK_TRANSFER_FAILED;
		}

		// -ECONNRESET -- we canceled this transfer
		if (result == -ECONNRESET) {
			US_DEBUGP("datafab_raw_bulk:  transfer aborted\n");
			return US_BULK_TRANSFER_ABORTED;
		}

		if (result == -EPIPE) {
			US_DEBUGP("datafab_raw_bulk:  output pipe stalled\n");
			return USB_STOR_TRANSPORT_FAILED;
		}

		// the catch-all case
		US_DEBUGP("datafab_raw_bulk:  unknown error\n");
		return US_BULK_TRANSFER_FAILED;
	}

	if (act_len != len) {
		US_DEBUGP("datafab_raw_bulk:  Warning. Transferred only %d bytes\n", act_len);
		return US_BULK_TRANSFER_SHORT;
	}

	US_DEBUGP("datafab_raw_bulk:  Transfered %d of %d bytes\n", act_len, len);
	return US_BULK_TRANSFER_GOOD;
}

static inline int datafab_bulk_read(struct us_data *us,
			            unsigned char *data, 
		                    unsigned int len)
{
	if (len == 0)
		return USB_STOR_TRANSPORT_GOOD;

	US_DEBUGP("datafab_bulk_read:  len = %d\n", len);
	return datafab_raw_bulk(SCSI_DATA_READ, us, data, len);
}


static inline int datafab_bulk_write(struct us_data *us,
			             unsigned char *data, 
		                     unsigned int len)
{
	if (len == 0)
		return USB_STOR_TRANSPORT_GOOD;

	US_DEBUGP("datafab_bulk_write:  len = %d\n", len);
	return datafab_raw_bulk(SCSI_DATA_WRITE, us, data, len);
}


static int datafab_read_data(struct us_data *us,
		             struct datafab_info *info,
		             u32 sector,
		             u32 sectors, 
		             unsigned char *dest, 
		             int use_sg)
{
	unsigned char command[8] = { 0, 0, 0, 0, 0, 0xE0, 0x20, 0x01 };
	unsigned char *buffer = NULL;
	unsigned char *ptr;
	unsigned char  thistime;
	struct scatterlist *sg = NULL;
	int totallen, len, result;
	int sg_idx = 0, current_sg_offset = 0;
	int transferred, rc;

	// we're working in LBA mode.  according to the ATA spec, 
	// we can support up to 28-bit addressing.  I don't know if Datafab
	// supports beyond 24-bit addressing.  It's kind of hard to test 
	// since it requires > 8GB CF card.
	//
	if (sectors > 0x0FFFFFFF)
		return USB_STOR_TRANSPORT_ERROR;

	if (info->lun == -1) {
		rc = datafab_determine_lun(us, info);
		if (rc != USB_STOR_TRANSPORT_GOOD)
			return rc;
	}

	command[5] += (info->lun << 4);

	// If we're using scatter-gather, we have to create a new
	// buffer to read all of the data in first, since a
	// scatter-gather buffer could in theory start in the middle
	// of a page, which would be bad. A developer who wants a
	// challenge might want to write a limited-buffer
	// version of this code.

	totallen = sectors * info->ssize;

	do {
		// loop, never allocate or transfer more than 64k at once (min(128k, 255*info->ssize) is the real limit)
		len = min_t(int, totallen, 65536);

		if (use_sg) {
			sg = (struct scatterlist *) dest;
			buffer = kmalloc(len, GFP_NOIO);
			if (buffer == NULL)
				return USB_STOR_TRANSPORT_ERROR;
			ptr = buffer;
		} else {
			ptr = dest;
		}

		thistime = (len / info->ssize) & 0xff;

		command[0] = 0;
		command[1] = thistime;
		command[2] = sector & 0xFF;
		command[3] = (sector >> 8) & 0xFF;
		command[4] = (sector >> 16) & 0xFF;
	
		command[5] |= (sector >> 24) & 0x0F;

		// send the command
		US_DEBUGP("datafab_read_data:  sending following command\n");
		datafab_dump_data(command, sizeof(command));

		result = datafab_bulk_write(us, command, sizeof(command));
		if (result != USB_STOR_TRANSPORT_GOOD) {
			if (use_sg)
				kfree(buffer);
			return result;
		}

		// read the result
		result = datafab_bulk_read(us, ptr, len);
		if (result != USB_STOR_TRANSPORT_GOOD) {
			if (use_sg)
				kfree(buffer);
			return result;
		}

		US_DEBUGP("datafab_read_data results:  %d bytes\n", len);
		// datafab_dump_data(ptr, len);

		sectors -= thistime;
		sector  += thistime;

		if (use_sg) {
			transferred = 0;
			while (sg_idx < use_sg && transferred < len) {
				if (len - transferred >= sg[sg_idx].length - current_sg_offset) {
					US_DEBUGP("datafab_read_data:  adding %d bytes to %d byte sg buffer\n", sg[sg_idx].length - current_sg_offset, sg[sg_idx].length);
					memcpy(sg[sg_idx].address + current_sg_offset,
					       buffer + transferred,
					       sg[sg_idx].length - current_sg_offset);
					transferred += sg[sg_idx].length - current_sg_offset;
					current_sg_offset = 0;
					// on to the next sg buffer
					++sg_idx;
				} else {
					US_DEBUGP("datafab_read_data:  adding %d bytes to %d byte sg buffer\n", len - transferred, sg[sg_idx].length);
					memcpy(sg[sg_idx].address + current_sg_offset,
					       buffer + transferred,
					       len - transferred);
					current_sg_offset += len - transferred;
					// this sg buffer is only partially full and we're out of data to copy in
					break;
				}
			}
			kfree(buffer);
		} else {
			dest += len;
		}

		totallen -= len;
	} while (totallen > 0);

	return USB_STOR_TRANSPORT_GOOD;
}


static int datafab_write_data(struct us_data *us,
		              struct datafab_info *info,
		              u32 sector,
		              u32 sectors, 
		              unsigned char *src, 
		              int use_sg)
{
	unsigned char command[8] = { 0, 0, 0, 0, 0, 0xE0, 0x30, 0x02 };
	unsigned char reply[2] = { 0, 0 };
	unsigned char *buffer = NULL;
	unsigned char *ptr;
	unsigned char thistime;
	struct scatterlist *sg = NULL;
	int totallen, len, result;
	int sg_idx = 0, current_sg_offset = 0;
	int transferred, rc;

	// we're working in LBA mode.  according to the ATA spec, 
	// we can support up to 28-bit addressing.  I don't know if Datafab
	// supports beyond 24-bit addressing.  It's kind of hard to test 
	// since it requires > 8GB CF card.
	//
	if (sectors > 0x0FFFFFFF)
		return USB_STOR_TRANSPORT_ERROR;

	if (info->lun == -1) {
		rc = datafab_determine_lun(us, info);
		if (rc != USB_STOR_TRANSPORT_GOOD)
			return rc;
	}

	command[5] += (info->lun << 4);

	// If we're using scatter-gather, we have to create a new
	// buffer to read all of the data in first, since a
	// scatter-gather buffer could in theory start in the middle
	// of a page, which would be bad. A developer who wants a
	// challenge might want to write a limited-buffer
	// version of this code.

	totallen = sectors * info->ssize;

	do {
		// loop, never allocate or transfer more than 64k at once (min(128k, 255*info->ssize) is the real limit)
		len = min_t(int, totallen, 65536);

		if (use_sg) {
			sg = (struct scatterlist *) src;
			buffer = kmalloc(len, GFP_NOIO);
			if (buffer == NULL)
				return USB_STOR_TRANSPORT_ERROR;
			ptr = buffer;

			memset(buffer, 0, len);

			// copy the data from the sg bufs into the big contiguous buf
			//
			transferred = 0;
			while (transferred < len) {
				if (len - transferred >= sg[sg_idx].length - current_sg_offset) {
					US_DEBUGP("datafab_write_data:  getting %d bytes from %d byte sg buffer\n", sg[sg_idx].length - current_sg_offset, sg[sg_idx].length);
					memcpy(ptr + transferred,
					       sg[sg_idx].address + current_sg_offset,
					       sg[sg_idx].length - current_sg_offset);
					transferred += sg[sg_idx].length - current_sg_offset;
					current_sg_offset = 0;
					// on to the next sg buffer
					++sg_idx;
				} else {
					US_DEBUGP("datafab_write_data:  getting %d bytes from %d byte sg buffer\n", len - transferred, sg[sg_idx].length);
					memcpy(ptr + transferred,
					       sg[sg_idx].address + current_sg_offset,
					       len - transferred);
					current_sg_offset += len - transferred;
					// we only copied part of this sg buffer
					break;
				}
			}
		} else {
			ptr = src;
		}

		thistime = (len / info->ssize) & 0xff;

		command[0] = 0;
		command[1] = thistime;
		command[2] = sector & 0xFF;
		command[3] = (sector >> 8) & 0xFF;
		command[4] = (sector >> 16) & 0xFF;

		command[5] |= (sector >> 24) & 0x0F;

		// send the command
		US_DEBUGP("datafab_write_data:  sending following command\n");
		datafab_dump_data(command, sizeof(command));

		result = datafab_bulk_write(us, command, sizeof(command));
		if (result != USB_STOR_TRANSPORT_GOOD) {
			if (use_sg)
				kfree(buffer);
			return result;
		}

		// send the data
		result = datafab_bulk_write(us, ptr, len);
		if (result != USB_STOR_TRANSPORT_GOOD) {
			if (use_sg)
				kfree(buffer);
			return result;
		}

		// read the result
		result = datafab_bulk_read(us, reply, sizeof(reply));
		if (result != USB_STOR_TRANSPORT_GOOD) {
			if (use_sg)
				kfree(buffer);
			return result;
		}

		if (reply[0] != 0x50 && reply[1] != 0) {
			US_DEBUGP("datafab_write_data:  Gah! write return code: %02x %02x\n", reply[0], reply[1]);
			if (use_sg)
				kfree(buffer);