drivers/usb/storage/option_ms.c

   1 /*
   2  * Driver for Option High Speed Mobile Devices.
   3  *
   4  *   (c) 2008 Dan Williams <dcbw@redhat.com>
   5  *
   6  * Inspiration taken from sierra_ms.c by Kevin Lloyd <klloyd@sierrawireless.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with this program; if not, write to the Free Software Foundation, Inc.,
  20  * 675 Mass Ave, Cambridge, MA 02139, USA.
  21  */
  22
  23 #include <linux/usb.h>
  24
  25 #include "usb.h"
  26 #include "transport.h"
  27 #include "option_ms.h"
  28 #include "debug.h"
  29
  30 #define ZCD_FORCE_MODEM                 0x01
  31 #define ZCD_ALLOW_MS                    0x02
  32
  33 static unsigned int option_zero_cd = ZCD_FORCE_MODEM;
  34 module_param(option_zero_cd, uint, S_IRUGO | S_IWUSR);
  35 MODULE_PARM_DESC(option_zero_cd, "ZeroCD mode (1=Force Modem (default),"
  36                  " 2=Allow CD-Rom");
  37
  38 #define RESPONSE_LEN 1024
  39
  40 static int option_rezero(struct us_data *us, int ep_in, int ep_out)
  41 {
  42         const unsigned char rezero_msg[] = {
  43           0x55, 0x53, 0x42, 0x43, 0x78, 0x56, 0x34, 0x12,
  44           0x01, 0x00, 0x00, 0x00, 0x80, 0x00, 0x06, 0x01,
  45           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  46           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
  47         };
  48         char *buffer;
  49         int result;
  50
  51         US_DEBUGP("Option MS: %s", "DEVICE MODE SWITCH\n");
  52
  53         buffer = kzalloc(RESPONSE_LEN, GFP_KERNEL);
  54         if (buffer == NULL)
  55                 return USB_STOR_TRANSPORT_ERROR;
  56
  57         memcpy(buffer, rezero_msg, sizeof (rezero_msg));
  58         result = usb_stor_bulk_transfer_buf(us,
  59                         usb_sndbulkpipe(us->pusb_dev, ep_out),
  60                         buffer, sizeof (rezero_msg), NULL);
  61         if (result != USB_STOR_XFER_GOOD) {
  62                 result = USB_STOR_XFER_ERROR;
  63                 goto out;
  64         }
  65
  66         /* Some of the devices need to be asked for a response, but we don't
  67          * care what that response is.
  68          */
  69         result = usb_stor_bulk_transfer_buf(us,
  70                         usb_sndbulkpipe(us->pusb_dev, ep_out),
  71                         buffer, RESPONSE_LEN, NULL);
  72         result = USB_STOR_XFER_GOOD;
  73
  74 out:
  75         kfree(buffer);
  76         return result;
  77 }
  78
  79 int option_ms_init(struct us_data *us)
  80 {
  81         struct usb_device *udev;
  82         struct usb_interface *intf;
  83         struct usb_host_interface *iface_desc;
  84         struct usb_endpoint_descriptor *endpoint = NULL;
  85         u8 ep_in = 0, ep_out = 0;
  86         int ep_in_size = 0, ep_out_size = 0;
  87         int i, result;
  88
  89         udev = us->pusb_dev;
  90         intf = us->pusb_intf;
  91
  92         /* Ensure it's really a ZeroCD device; devices that are already
  93          * in modem mode return 0xFF for class, subclass, and protocol.
  94          */
  95         if (udev->descriptor.bDeviceClass != 0 ||
  96             udev->descriptor.bDeviceSubClass != 0 ||
  97             udev->descriptor.bDeviceProtocol != 0)
  98                 return USB_STOR_TRANSPORT_GOOD;
  99
 100         US_DEBUGP("Option MS: option_ms_init called\n");
 101
 102         /* Find the right mass storage interface */
 103         iface_desc = intf->cur_altsetting;
 104         if (iface_desc->desc.bInterfaceClass != 0x8 ||
 105             iface_desc->desc.bInterfaceSubClass != 0x6 ||
 106             iface_desc->desc.bInterfaceProtocol != 0x50) {
 107                 US_DEBUGP("Option MS: mass storage interface not found, no action "
 108                           "required\n");
 109                 return USB_STOR_TRANSPORT_GOOD;
 110         }
 111
 112         /* Find the mass storage bulk endpoints */
 113         for (i = 0; i < iface_desc->desc.bNumEndpoints && (!ep_in_size || !ep_out_size); ++i) {
 114                 endpoint = &iface_desc->endpoint[i].desc;
 115
 116                 if (usb_endpoint_is_bulk_in(endpoint)) {
 117                         ep_in = usb_endpoint_num(endpoint);
 118                         ep_in_size = le16_to_cpu(endpoint->wMaxPacketSize);
 119                 } else if (usb_endpoint_is_bulk_out(endpoint)) {
 120                         ep_out = usb_endpoint_num(endpoint);
 121                         ep_out_size = le16_to_cpu(endpoint->wMaxPacketSize);
 122                 }
 123         }
 124
 125         /* Can't find the mass storage endpoints */
 126         if (!ep_in_size || !ep_out_size) {
 127                 US_DEBUGP("Option MS: mass storage endpoints not found, no action "
 128                           "required\n");
 129                 return USB_STOR_TRANSPORT_GOOD;
 130         }
 131
 132         /* Force Modem mode */
 133         if (option_zero_cd == ZCD_FORCE_MODEM) {
 134                 US_DEBUGP("Option MS: %s", "Forcing Modem Mode\n");
 135                 result = option_rezero(us, ep_in, ep_out);
 136                 if (result != USB_STOR_XFER_GOOD)
 137                         US_DEBUGP("Option MS: Failed to switch to modem mode.\n");
 138                 return -EIO;
 139         } else if (option_zero_cd == ZCD_ALLOW_MS) {
 140                 /* Allow Mass Storage mode (keep CD-Rom) */
 141                 US_DEBUGP("Option MS: %s", "Allowing Mass Storage Mode if device"
 142                           " requests it\n");
 143         }
 144
 145         return USB_STOR_TRANSPORT_GOOD;
 146 }
 147