Free Electrons

Embedded Linux Experts

/*
 * Driver for Option High Speed Mobile Devices.
 *
 *   (c) 2008 Dan Williams <dcbw@redhat.com>
 *
 * Inspiration taken from sierra_ms.c by Kevin Lloyd <klloyd@sierrawireless.com>
 *
 * 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 of the License, 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.
 */

#include <linux/usb.h>

#include "usb.h"
#include "transport.h"
#include "option_ms.h"
#include "debug.h"

#define ZCD_FORCE_MODEM			0x01
#define ZCD_ALLOW_MS 			0x02

static unsigned int option_zero_cd = ZCD_FORCE_MODEM;
module_param(option_zero_cd, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(option_zero_cd, "ZeroCD mode (1=Force Modem (default),"
		 " 2=Allow CD-Rom");

#define RESPONSE_LEN 1024

static int option_rezero(struct us_data *us)
{
	const unsigned char rezero_msg[] = {
	  0x55, 0x53, 0x42, 0x43, 0x78, 0x56, 0x34, 0x12,
	  0x01, 0x00, 0x00, 0x00, 0x80, 0x00, 0x06, 0x01,
	  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
	};
	char *buffer;
	int result;

	US_DEBUGP("Option MS: %s", "DEVICE MODE SWITCH\n");

	buffer = kzalloc(RESPONSE_LEN, GFP_KERNEL);
	if (buffer == NULL)
		return USB_STOR_TRANSPORT_ERROR;

	memcpy(buffer, rezero_msg, sizeof(rezero_msg));
	result = usb_stor_bulk_transfer_buf(us,
			us->send_bulk_pipe,
			buffer, sizeof(rezero_msg), NULL);
	if (result != USB_STOR_XFER_GOOD) {
		result = USB_STOR_XFER_ERROR;
		goto out;
	}

	/* Some of the devices need to be asked for a response, but we don't
	 * care what that response is.
	 */
	usb_stor_bulk_transfer_buf(us,
			us->recv_bulk_pipe,
			buffer, RESPONSE_LEN, NULL);

	/* Read the CSW */
	usb_stor_bulk_transfer_buf(us,
			us->recv_bulk_pipe,
			buffer, 13, NULL);

	result = USB_STOR_XFER_GOOD;

out:
	kfree(buffer);
	return result;
}

static int option_inquiry(struct us_data *us)
{
	const unsigned char inquiry_msg[] = {
	  0x55, 0x53, 0x42, 0x43, 0x12, 0x34, 0x56, 0x78,
	  0x24, 0x00, 0x00, 0x00, 0x80, 0x00, 0x06, 0x12,
	  0x00, 0x00, 0x00, 0x24, 0x00, 0x00, 0x00, 0x00,
	  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
	};
	char *buffer;
	int result;

	US_DEBUGP("Option MS: %s", "device inquiry for vendor name\n");

	buffer = kzalloc(0x24, GFP_KERNEL);
	if (buffer == NULL)
		return USB_STOR_TRANSPORT_ERROR;

	memcpy(buffer, inquiry_msg, sizeof(inquiry_msg));
	result = usb_stor_bulk_transfer_buf(us,
			us->send_bulk_pipe,
			buffer, sizeof(inquiry_msg), NULL);
	if (result != USB_STOR_XFER_GOOD) {
		result = USB_STOR_XFER_ERROR;
		goto out;
	}

	result = usb_stor_bulk_transfer_buf(us,
			us->recv_bulk_pipe,
			buffer, 0x24, NULL);
	if (result != USB_STOR_XFER_GOOD) {
		result = USB_STOR_XFER_ERROR;
		goto out;
	}

	result = memcmp(buffer+8, "Option", 6);

	if (result != 0)
		result = memcmp(buffer+8, "ZCOPTION", 8);

	/* Read the CSW */
	usb_stor_bulk_transfer_buf(us,
			us->recv_bulk_pipe,
			buffer, 13, NULL);

out:
	kfree(buffer);
	return result;
}


int option_ms_init(struct us_data *us)
{
	int result;

	US_DEBUGP("Option MS: option_ms_init called\n");

	/* Additional test for vendor information via INQUIRY,
	 * because some vendor/product IDs are ambiguous
	 */
	result = option_inquiry(us);
	if (result != 0) {
		US_DEBUGP("Option MS: vendor is not Option or not determinable,"
			  " no action taken\n");
		return 0;
	} else
		US_DEBUGP("Option MS: this is a genuine Option device,"
			  " proceeding\n");

	/* Force Modem mode */
	if (option_zero_cd == ZCD_FORCE_MODEM) {
		US_DEBUGP("Option MS: %s", "Forcing Modem Mode\n");
		result = option_rezero(us);
		if (result != USB_STOR_XFER_GOOD)
			US_DEBUGP("Option MS: Failed to switch to modem mode.\n");
		return -EIO;
	} else if (option_zero_cd == ZCD_ALLOW_MS) {
		/* Allow Mass Storage mode (keep CD-Rom) */
		US_DEBUGP("Option MS: %s", "Allowing Mass Storage Mode if device"
		          " requests it\n");
	}

	return 0;
}