1 files changed, 103 insertions, 39 deletions

diff --git a/drivers/usb/gadget/ether.c b/drivers/usb/gadget/ether.c
index ca8e0ebc79e8..72e2b65293c8 100644
--- a/drivers/usb/gadget/ether.c
+++ b/drivers/usb/gadget/ether.c
@@ -72,9 +72,18 @@
  *
  * There's some hardware that can't talk CDC.  We make that hardware
  * implement a "minimalist" vendor-agnostic CDC core:  same framing, but
- * link-level setup only requires activating the configuration.
- * Linux supports it, but other host operating systems may not.
- * (This is a subset of CDC Ethernet.)
+ * link-level setup only requires activating the configuration.  Only the
+ * endpoint descriptors, and product/vendor IDs, are relevant; no control
+ * operations are available.  Linux supports it, but other host operating
+ * systems may not.  (This is a subset of CDC Ethernet.)
+ *
+ * It turns out that if you add a few descriptors to that "CDC Subset",
+ * (Windows) host side drivers from MCCI can treat it as one submode of
+ * a proprietary scheme called "SAFE" ... without needing to know about
+ * specific product/vendor IDs.  So we do that, making it easier to use
+ * those MS-Windows drivers.  Those added descriptors make it resemble a
+ * CDC MDLM device, but they don't change device behavior at all.  (See
+ * MCCI Engineering report 950198 "SAFE Networking Functions".)
  *
  * A third option is also in use.  Rather than CDC Ethernet, or something
  * simpler, Microsoft pushes their own approach: RNDIS.  The published
@@ -254,6 +263,10 @@ MODULE_PARM_DESC(host_addr, "Host Ethernet Address");
 #define DEV_CONFIG_CDC
 #endif
 
+#ifdef CONFIG_USB_GADGET_S3C2410
+#define DEV_CONFIG_CDC
+#endif
+
 #ifdef CONFIG_USB_GADGET_AT91
 #define DEV_CONFIG_CDC
 #endif
@@ -283,9 +296,6 @@ MODULE_PARM_DESC(host_addr, "Host Ethernet Address");
 #define DEV_CONFIG_SUBSET
 #endif
 
-#ifdef CONFIG_USB_GADGET_S3C2410
-#define DEV_CONFIG_CDC
-#endif
 
 /*-------------------------------------------------------------------------*/
 
@@ -487,8 +497,17 @@ rndis_config = {
  * endpoint.  Both have a "data" interface and two bulk endpoints.
  * There are also differences in how control requests are handled.
  *
- * RNDIS shares a lot with CDC-Ethernet, since it's a variant of
- * the CDC-ACM (modem) spec.
+ * RNDIS shares a lot with CDC-Ethernet, since it's a variant of the
+ * CDC-ACM (modem) spec.  Unfortunately MSFT's RNDIS driver is buggy; it
+ * may hang or oops.  Since bugfixes (or accurate specs, letting Linux
+ * work around those bugs) are unlikely to ever come from MSFT, you may
+ * wish to avoid using RNDIS.
+ *
+ * MCCI offers an alternative to RNDIS if you need to connect to Windows
+ * but have hardware that can't support CDC Ethernet.   We add descriptors
+ * to present the CDC Subset as a (nonconformant) CDC MDLM variant called
+ * "SAFE".  That borrows from both CDC Ethernet and CDC MDLM.  You can
+ * get those drivers from MCCI, or bundled with various products.
  */
 
 #ifdef  DEV_CONFIG_CDC
@@ -522,8 +541,6 @@ rndis_control_intf = {
 };
 #endif
 
-#if defined(DEV_CONFIG_CDC) || defined(CONFIG_USB_ETH_RNDIS)
-
 static const struct usb_cdc_header_desc header_desc = {
         .bLength =              sizeof header_desc,
         .bDescriptorType =      USB_DT_CS_INTERFACE,
@@ -532,6 +549,8 @@ static const struct usb_cdc_header_desc header_desc = {
         .bcdCDC =               __constant_cpu_to_le16 (0x0110),
 };
 
+#if defined(DEV_CONFIG_CDC) || defined(CONFIG_USB_ETH_RNDIS)
+
 static const struct usb_cdc_union_desc union_desc = {
         .bLength =              sizeof union_desc,
         .bDescriptorType =      USB_DT_CS_INTERFACE,
@@ -564,7 +583,40 @@ static const struct usb_cdc_acm_descriptor acm_descriptor = {
 
 #endif
 
-#ifdef  DEV_CONFIG_CDC
+#ifndef DEV_CONFIG_CDC
+
+/* "SAFE" loosely follows CDC WMC MDLM, violating the spec in various
+ * ways:  data endpoints live in the control interface, there's no data
+ * interface, and it's not used to talk to a cell phone radio.
+ */
+
+static const struct usb_cdc_mdlm_desc mdlm_desc = {
+        .bLength =              sizeof mdlm_desc,
+        .bDescriptorType =      USB_DT_CS_INTERFACE,
+        .bDescriptorSubType =   USB_CDC_MDLM_TYPE,
+
+        .bcdVersion =           __constant_cpu_to_le16(0x0100),
+        .bGUID = {
+                0x5d, 0x34, 0xcf, 0x66, 0x11, 0x18, 0x11, 0xd6,
+                0xa2, 0x1a, 0x00, 0x01, 0x02, 0xca, 0x9a, 0x7f,
+        },
+};
+
+/* since "usb_cdc_mdlm_detail_desc" is a variable length structure, we
+ * can't really use its struct.  All we do here is say that we're using
+ * the submode of "SAFE" which directly matches the CDC Subset.
+ */
+static const u8 mdlm_detail_desc[] = {
+        6,
+        USB_DT_CS_INTERFACE,
+        USB_CDC_MDLM_DETAIL_TYPE,
+
+        0,      /* "SAFE" */
+        0,      /* network control capabilities (none) */
+        0,      /* network data capabilities ("raw" encapsulation) */
+};
+
+#endif
 
 static const struct usb_cdc_ether_desc ether_desc = {
         .bLength =              sizeof ether_desc,
@@ -579,7 +631,6 @@ static const struct usb_cdc_ether_desc ether_desc = {
         .bNumberPowerFilters =  0,
 };
 
-#endif
 
 #if defined(DEV_CONFIG_CDC) || defined(CONFIG_USB_ETH_RNDIS)
 
@@ -672,6 +723,9 @@ rndis_data_intf = {
 /*
  * "Simple" CDC-subset option is a simple vendor-neutral model that most
  * full speed controllers can handle:  one interface, two bulk endpoints.
+ *
+ * To assist host side drivers, we fancy it up a bit, and add descriptors
+ * so some host side drivers will understand it as a "SAFE" variant.
  */
 
 static const struct usb_interface_descriptor
@@ -682,8 +736,8 @@ subset_data_intf = {
         .bInterfaceNumber =     0,
         .bAlternateSetting =    0,
         .bNumEndpoints =        2,
-        .bInterfaceClass =      USB_CLASS_VENDOR_SPEC,
-        .bInterfaceSubClass =   0,
+        .bInterfaceClass =      USB_CLASS_COMM,
+        .bInterfaceSubClass =   USB_CDC_SUBCLASS_MDLM,
         .bInterfaceProtocol =   0,
         .iInterface =           STRING_DATA,
 };
@@ -731,10 +785,15 @@ static const struct usb_descriptor_header *fs_eth_function [11] = {
 static inline void __init fs_subset_descriptors(void)
 {
 #ifdef DEV_CONFIG_SUBSET
+        /* behavior is "CDC Subset"; extra descriptors say "SAFE" */
         fs_eth_function[1] = (struct usb_descriptor_header *) &subset_data_intf;
-        fs_eth_function[2] = (struct usb_descriptor_header *) &fs_source_desc;
-        fs_eth_function[3] = (struct usb_descriptor_header *) &fs_sink_desc;
-        fs_eth_function[4] = NULL;
+        fs_eth_function[2] = (struct usb_descriptor_header *) &header_desc;
+        fs_eth_function[3] = (struct usb_descriptor_header *) &mdlm_desc;
+        fs_eth_function[4] = (struct usb_descriptor_header *) &mdlm_detail_desc;
+        fs_eth_function[5] = (struct usb_descriptor_header *) &ether_desc;
+        fs_eth_function[6] = (struct usb_descriptor_header *) &fs_source_desc;
+        fs_eth_function[7] = (struct usb_descriptor_header *) &fs_sink_desc;
+        fs_eth_function[8] = NULL;
 #else
         fs_eth_function[1] = NULL;
 #endif
@@ -828,10 +887,15 @@ static const struct usb_descriptor_header *hs_eth_function [11] = {
 static inline void __init hs_subset_descriptors(void)
 {
 #ifdef DEV_CONFIG_SUBSET
+        /* behavior is "CDC Subset"; extra descriptors say "SAFE" */
         hs_eth_function[1] = (struct usb_descriptor_header *) &subset_data_intf;
-        hs_eth_function[2] = (struct usb_descriptor_header *) &fs_source_desc;
-        hs_eth_function[3] = (struct usb_descriptor_header *) &fs_sink_desc;
-        hs_eth_function[4] = NULL;
+        hs_eth_function[2] = (struct usb_descriptor_header *) &header_desc;
+        hs_eth_function[3] = (struct usb_descriptor_header *) &mdlm_desc;
+        hs_eth_function[4] = (struct usb_descriptor_header *) &mdlm_detail_desc;
+        hs_eth_function[5] = (struct usb_descriptor_header *) &ether_desc;
+        hs_eth_function[6] = (struct usb_descriptor_header *) &hs_source_desc;
+        hs_eth_function[7] = (struct usb_descriptor_header *) &hs_sink_desc;
+        hs_eth_function[8] = NULL;
 #else
         hs_eth_function[1] = NULL;
 #endif
@@ -878,10 +942,8 @@ static char				manufacturer [50];
 static char                             product_desc [40] = DRIVER_DESC;
 static char                             serial_number [20];
 
-#ifdef  DEV_CONFIG_CDC
 /* address that the host will use ... usually assigned at random */
 static char                             ethaddr [2 * ETH_ALEN + 1];
-#endif
 
 /* static strings, in UTF-8 */
 static struct usb_string                strings [] = {
@@ -889,9 +951,9 @@ static struct usb_string		strings [] = {
         { STRING_PRODUCT,       product_desc, },
         { STRING_SERIALNUMBER,  serial_number, },
         { STRING_DATA,          "Ethernet Data", },
+        { STRING_ETHADDR,       ethaddr, },
 #ifdef  DEV_CONFIG_CDC
         { STRING_CDC,           "CDC Ethernet", },
-        { STRING_ETHADDR,       ethaddr, },
         { STRING_CONTROL,       "CDC Communications Control", },
 #endif
 #ifdef  DEV_CONFIG_SUBSET
@@ -986,10 +1048,10 @@ set_ether_config (struct eth_dev *dev, gfp_t gfp_flags)
         }
 #endif
 
-        dev->in = ep_desc (dev->gadget, &hs_source_desc, &fs_source_desc);
+        dev->in = ep_desc(gadget, &hs_source_desc, &fs_source_desc);
         dev->in_ep->driver_data = dev;
 
-        dev->out = ep_desc (dev->gadget, &hs_sink_desc, &fs_sink_desc);
+        dev->out = ep_desc(gadget, &hs_sink_desc, &fs_sink_desc);
         dev->out_ep->driver_data = dev;
 
         /* With CDC,  the host isn't allowed to use these two data
@@ -2278,10 +2340,10 @@ eth_bind (struct usb_gadget *gadget)
                         "RNDIS/%s", driver_desc);
 
         /* CDC subset ... recognized by Linux since 2.4.10, but Windows
-         * drivers aren't widely available.
+         * drivers aren't widely available.  (That may be improved by
+         * supporting one submode of the "SAFE" variant of MDLM.)
          */
         } else if (!cdc) {
-                device_desc.bDeviceClass = USB_CLASS_VENDOR_SPEC;
                 device_desc.idVendor =
                         __constant_cpu_to_le16(SIMPLE_VENDOR_NUM);
                 device_desc.idProduct =
@@ -2352,6 +2414,10 @@ autoconf_fail:
         if (!cdc) {
                 eth_config.bNumInterfaces = 1;
                 eth_config.iConfiguration = STRING_SUBSET;
+
+                /* use functions to set these up, in case we're built to work
+                 * with multiple controllers and must override CDC Ethernet.
+                 */
                 fs_subset_descriptors();
                 hs_subset_descriptors();
         }
@@ -2415,22 +2481,20 @@ autoconf_fail:
 
         /* Module params for these addresses should come from ID proms.
          * The host side address is used with CDC and RNDIS, and commonly
-         * ends up in a persistent config database.
+         * ends up in a persistent config database.  It's not clear if
+         * host side code for the SAFE thing cares -- its original BLAN
+         * thing didn't, Sharp never assigned those addresses on Zaurii.
          */
         if (get_ether_addr(dev_addr, net->dev_addr))
                 dev_warn(&gadget->dev,
                         "using random %s ethernet address\n", "self");
-        if (cdc || rndis) {
-                if (get_ether_addr(host_addr, dev->host_mac))
-                        dev_warn(&gadget->dev,
-                                "using random %s ethernet address\n", "host");
-#ifdef  DEV_CONFIG_CDC
-                snprintf (ethaddr, sizeof ethaddr, "%02X%02X%02X%02X%02X%02X",
-                        dev->host_mac [0], dev->host_mac [1],
-                        dev->host_mac [2], dev->host_mac [3],
-                        dev->host_mac [4], dev->host_mac [5]);
-#endif
-        }
+        if (get_ether_addr(host_addr, dev->host_mac))
+                dev_warn(&gadget->dev,
+                        "using random %s ethernet address\n", "host");
+        snprintf (ethaddr, sizeof ethaddr, "%02X%02X%02X%02X%02X%02X",
+                dev->host_mac [0], dev->host_mac [1],
+                dev->host_mac [2], dev->host_mac [3],
+                dev->host_mac [4], dev->host_mac [5]);
 
         if (rndis) {
                 status = rndis_init();