option_ms.c

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/*
 * Driver for Option High Speed Mobile Devices.
 *
 *   (c) 2008 Dan Williams <[email protected]>
 *
 * Inspiration taken from sierra_ms.c by Kevin Lloyd <[email protected]>
 *
 * 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 <linux/slab.h>
#include <linux/module.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;
}