root/drivers/usb/storage/option_ms.c

DEFINITIONS

1. option_rezero
2. option_inquiry
3. option_ms_init

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Driver for Option High Speed Mobile Devices.
   4  *
   5  *   (c) 2008 Dan Williams <dcbw@redhat.com>
   6  *
   7  * Inspiration taken from sierra_ms.c by Kevin Lloyd <klloyd@sierrawireless.com>
   8  */
   9 
  10 #include <linux/usb.h>
  11 #include <linux/slab.h>
  12 #include <linux/module.h>
  13 
  14 #include "usb.h"
  15 #include "transport.h"
  16 #include "option_ms.h"
  17 #include "debug.h"
  18 
  19 #define ZCD_FORCE_MODEM                 0x01
  20 #define ZCD_ALLOW_MS                    0x02
  21 
  22 static unsigned int option_zero_cd = ZCD_FORCE_MODEM;
  23 module_param(option_zero_cd, uint, S_IRUGO | S_IWUSR);
  24 MODULE_PARM_DESC(option_zero_cd, "ZeroCD mode (1=Force Modem (default),"
  25                  " 2=Allow CD-Rom");
  26 
  27 #define RESPONSE_LEN 1024
  28 
  29 static int option_rezero(struct us_data *us)
  30 {
  31         static const unsigned char rezero_msg[] = {
  32           0x55, 0x53, 0x42, 0x43, 0x78, 0x56, 0x34, 0x12,
  33           0x01, 0x00, 0x00, 0x00, 0x80, 0x00, 0x06, 0x01,
  34           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  35           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
  36         };
  37         char *buffer;
  38         int result;
  39 
  40         usb_stor_dbg(us, "Option MS: %s\n", "DEVICE MODE SWITCH");
  41 
  42         buffer = kzalloc(RESPONSE_LEN, GFP_KERNEL);
  43         if (buffer == NULL)
  44                 return USB_STOR_TRANSPORT_ERROR;
  45 
  46         memcpy(buffer, rezero_msg, sizeof(rezero_msg));
  47         result = usb_stor_bulk_transfer_buf(us,
  48                         us->send_bulk_pipe,
  49                         buffer, sizeof(rezero_msg), NULL);
  50         if (result != USB_STOR_XFER_GOOD) {
  51                 result = USB_STOR_XFER_ERROR;
  52                 goto out;
  53         }
  54 
  55         /*
  56          * Some of the devices need to be asked for a response, but we don't
  57          * care what that response is.
  58          */
  59         usb_stor_bulk_transfer_buf(us,
  60                         us->recv_bulk_pipe,
  61                         buffer, RESPONSE_LEN, NULL);
  62 
  63         /* Read the CSW */
  64         usb_stor_bulk_transfer_buf(us,
  65                         us->recv_bulk_pipe,
  66                         buffer, 13, NULL);
  67 
  68         result = USB_STOR_XFER_GOOD;
  69 
  70 out:
  71         kfree(buffer);
  72         return result;
  73 }
  74 
  75 static int option_inquiry(struct us_data *us)
  76 {
  77         static const unsigned char inquiry_msg[] = {
  78           0x55, 0x53, 0x42, 0x43, 0x12, 0x34, 0x56, 0x78,
  79           0x24, 0x00, 0x00, 0x00, 0x80, 0x00, 0x06, 0x12,
  80           0x00, 0x00, 0x00, 0x24, 0x00, 0x00, 0x00, 0x00,
  81           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
  82         };
  83         char *buffer;
  84         int result;
  85 
  86         usb_stor_dbg(us, "Option MS: %s\n", "device inquiry for vendor name");
  87 
  88         buffer = kzalloc(0x24, GFP_KERNEL);
  89         if (buffer == NULL)
  90                 return USB_STOR_TRANSPORT_ERROR;
  91 
  92         memcpy(buffer, inquiry_msg, sizeof(inquiry_msg));
  93         result = usb_stor_bulk_transfer_buf(us,
  94                         us->send_bulk_pipe,
  95                         buffer, sizeof(inquiry_msg), NULL);
  96         if (result != USB_STOR_XFER_GOOD) {
  97                 result = USB_STOR_XFER_ERROR;
  98                 goto out;
  99         }
 100 
 101         result = usb_stor_bulk_transfer_buf(us,
 102                         us->recv_bulk_pipe,
 103                         buffer, 0x24, NULL);
 104         if (result != USB_STOR_XFER_GOOD) {
 105                 result = USB_STOR_XFER_ERROR;
 106                 goto out;
 107         }
 108 
 109         result = memcmp(buffer+8, "Option", 6);
 110 
 111         if (result != 0)
 112                 result = memcmp(buffer+8, "ZCOPTION", 8);
 113 
 114         /* Read the CSW */
 115         usb_stor_bulk_transfer_buf(us,
 116                         us->recv_bulk_pipe,
 117                         buffer, 13, NULL);
 118 
 119 out:
 120         kfree(buffer);
 121         return result;
 122 }
 123 
 124 
 125 int option_ms_init(struct us_data *us)
 126 {
 127         int result;
 128 
 129         usb_stor_dbg(us, "Option MS: %s\n", "option_ms_init called");
 130 
 131         /*
 132          * Additional test for vendor information via INQUIRY,
 133          * because some vendor/product IDs are ambiguous
 134          */
 135         result = option_inquiry(us);
 136         if (result != 0) {
 137                 usb_stor_dbg(us, "Option MS: %s\n",
 138                              "vendor is not Option or not determinable, no action taken");
 139                 return 0;
 140         } else
 141                 usb_stor_dbg(us, "Option MS: %s\n",
 142                              "this is a genuine Option device, proceeding");
 143 
 144         /* Force Modem mode */
 145         if (option_zero_cd == ZCD_FORCE_MODEM) {
 146                 usb_stor_dbg(us, "Option MS: %s\n", "Forcing Modem Mode");
 147                 result = option_rezero(us);
 148                 if (result != USB_STOR_XFER_GOOD)
 149                         usb_stor_dbg(us, "Option MS: %s\n",
 150                                      "Failed to switch to modem mode");
 151                 return -EIO;
 152         } else if (option_zero_cd == ZCD_ALLOW_MS) {
 153                 /* Allow Mass Storage mode (keep CD-Rom) */
 154                 usb_stor_dbg(us, "Option MS: %s\n",
 155                              "Allowing Mass Storage Mode if device requests it");
 156         }
 157 
 158         return 0;
 159 }
 160