// SPDX-License-Identifier: GPL-2.0+
/*
* f_subset.c -- "CDC Subset" Ethernet link function driver
*
* Copyright (C) 2003-2005,2008 David Brownell
* Copyright (C) 2008 Nokia Corporation
*/
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/etherdevice.h>
#include "u_ether.h"
#include "u_ether_configfs.h"
#include "u_gether.h"
/*
* This function packages a simple "CDC Subset" Ethernet port with no real
* control mechanisms; just raw data transfer over two bulk endpoints.
* The data transfer model is exactly that of CDC Ethernet, which is
* why we call it the "CDC Subset".
*
* Because it's not standardized, this has some interoperability issues.
* They mostly relate to driver binding, since the data transfer model is
* so simple (CDC Ethernet). The original versions of this protocol used
* specific product/vendor IDs: byteswapped IDs for Digital Equipment's
* SA-1100 "Itsy" board, which could run Linux 2.4 kernels and supported
* daughtercards with USB peripheral connectors. (It was used more often
* with other boards, using the Itsy identifiers.) Linux hosts recognized
* this with CONFIG_USB_ARMLINUX; these devices have only one configuration
* and one interface.
*
* At some point, MCCI defined a (nonconformant) CDC MDLM variant called
* "SAFE", which happens to have a mode which is identical to the "CDC
* Subset" in terms of data transfer and lack of control model. This was
* adopted by later Sharp Zaurus models, and by some other software which
* Linux hosts recognize with CONFIG_USB_NET_ZAURUS.
*
* Because Microsoft's RNDIS drivers are far from robust, we added a few
* descriptors to the CDC Subset code, making this code look like a SAFE
* implementation. This lets you use MCCI's host side MS-Windows drivers
* if you get fed up with RNDIS. It also makes it easier for composite
* drivers to work, since they can use class based binding instead of
* caring about specific product and vendor IDs.
*/
struct f_gether {
struct gether port;
char ethaddr[14];
};
static inline struct f_gether *func_to_geth(struct usb_function *f)
{
return container_of(f, struct f_gether, port.func);
}
/*-------------------------------------------------------------------------*/
/*
* "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.
*
* "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.
*/
/* interface descriptor: */
static struct usb_interface_descriptor subset_data_intf = {
.bLength = sizeof subset_data_intf,
.bDescriptorType = USB_DT_INTERFACE,
/* .bInterfaceNumber = DYNAMIC */
.bAlternateSetting = 0,
.bNumEndpoints = 2,
.bInterfaceClass = USB_CLASS_COMM,
.bInterfaceSubClass = USB_CDC_SUBCLASS_MDLM,
.bInterfaceProtocol = 0,
/* .iInterface = DYNAMIC */
};
static struct usb_cdc_header_desc mdlm_header_desc = {
.bLength = sizeof mdlm_header_desc,
.bDescriptorType = USB_DT_CS_INTERFACE,
.bDescriptorSubType = USB_CDC_HEADER_TYPE,
.bcdCDC = cpu_to_le16(0x0110),
};
static struct usb_cdc_mdlm_desc mdlm_desc = {
.bLength = sizeof mdlm_desc,
.bDescriptorType = USB_DT_CS_INTERFACE,
.bDescriptorSubType = USB_CDC_MDLM_TYPE,
.bcdVersion = 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 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) */
};
static struct usb_cdc_ether_desc ether_desc = {
.bLength = sizeof ether_desc,
.bDescriptorType = USB_DT_CS_INTERFACE,
.bDescriptorSubType = USB_CDC_ETHERNET_TYPE,
/* this descriptor actually adds value, surprise! */
/* .iMACAddress = DYNAMIC */
.bmEthernetStatistics = cpu_to_le32(0), /* no statistics */
.wMaxSegmentSize = cpu_to_le16(ETH_FRAME_LEN),
.wNumberMCFilters = cpu_to_le16(0),
.bNumberPowerFilters = 0,
};
/* full speed support: */
static struct usb_endpoint_descriptor fs_subset_in_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bEndpointAddress = USB_DIR_IN,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
};
static struct usb_endpoint_descriptor fs_subset_out_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bEndpointAddress = USB_DIR_OUT,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
};
static struct usb_descriptor_header *fs_eth_function[] = {
(struct usb_descriptor_header *) &subset_data_intf,
(struct usb_descriptor_header *) &mdlm_header_desc,
(struct usb_descriptor_header *) &mdlm_desc,
(struct usb_descriptor_header *) &mdlm_detail_desc,
(struct usb_descriptor_header *) ðer_desc,
(struct usb_descriptor_header *) &fs_subset_in_desc,
(struct usb_descriptor_header *) &fs_subset_out_desc,
NULL,
};
/* high speed support: */
static struct usb_endpoint_descriptor hs_subset_in_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
.wMaxPacketSize = cpu_to_le16(512),
};
static struct usb_endpoint_descriptor hs_subset_out_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
.wMaxPacketSize = cpu_to_le16(512),
};
static struct usb_descriptor_header *hs_eth_function[] = {
(struct usb_descriptor_header *) &subset_data_intf,
(struct usb_descriptor_header *) &mdlm_header_desc,
(struct usb_descriptor_header *) &mdlm_desc,
(struct usb_descriptor_header *) &mdlm_detail_desc,
(struct usb_descriptor_header *) ðer_desc,
(struct usb_descriptor_header *) &hs_subset_in_desc,
(struct usb_descriptor_header *) &hs_subset_out_desc,
NULL,
};
/* super speed support: */
static struct usb_endpoint_descriptor ss_subset_in_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
.wMaxPacketSize = cpu_to_le16(1024),
};
static struct usb_endpoint_descriptor ss_subset_out_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
.wMaxPacketSize = cpu_to_le16(1024),
};
static struct usb_ss_ep_comp_descriptor ss_subset_bulk_comp_desc = {
.bLength = sizeof ss_subset_bulk_comp_desc,
.bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
/* the following 2 values can be tweaked if necessary */
/* .bMaxBurst = 0, */
/* .bmAttributes = 0, */
};
static struct usb_descriptor_header *ss_eth_function[] = {
(struct usb_descriptor_header *) &subset_data_intf,
(struct usb_descriptor_header *) &mdlm_header_desc,
(struct usb_descriptor_header *) &mdlm_desc,
(struct usb_descriptor_header *) &mdlm_detail_desc,
(struct usb_descriptor_header *) ðer_desc,
(struct usb_descriptor_header *) &ss_subset_in_desc,
(struct usb_descriptor_header *) &ss_subset_bulk_comp_desc,
(struct usb_descriptor_header *) &ss_subset_out_desc,
(struct usb_descriptor_header *) &ss_subset_bulk_comp_desc,
NULL,
};
/* string descriptors: */
static struct usb_string geth_string_defs[] = {
[0].s = "CDC Ethernet Subset/SAFE",
[1].s = "",
{ } /* end of list */
};
static struct usb_gadget_strings geth_string_table = {
.language = 0x0409, /* en-us */
.strings = geth_string_defs,
};
static struct usb_gadget_strings *geth_strings[] = {
&geth_string_table,
NULL,
};
/*-------------------------------------------------------------------------*/
static int geth_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
{
struct f_gether *geth = func_to_geth(f);
struct usb_composite_dev *cdev = f->config->cdev;
struct net_device *net;
/* we know alt == 0, so this is an activation or a reset */
if (geth->port.in_ep->enabled) {
DBG(cdev, "reset cdc subset\n");
gether_disconnect(&geth->port);
}
DBG(cdev, "init + activate cdc subset\n");
if (config_ep_by_speed(cdev->gadget, f, geth->port.in_ep) ||
config_ep_by_speed(cdev->gadget, f, geth->port.out_ep)) {
geth->port.in_ep->desc = NULL;
geth->port.out_ep->desc = NULL;
return -EINVAL;
}
net = gether_connect(&geth->port);
return PTR_ERR_OR_ZERO(net);
}
static void geth_disable(struct usb_function *f)
{
struct f_gether *geth = func_to_geth(f);
struct usb_composite_dev *cdev = f->config->cdev;
DBG(cdev, "net deactivated\n");
gether_disconnect(&geth->port);
}
/*-------------------------------------------------------------------------*/
/* serial function driver setup/binding */
static int
geth_bind(struct usb_configuration *c, struct usb_function *f)
{
struct usb_composite_dev *cdev = c->cdev;
struct f_gether *geth = func_to_geth(f);
struct usb_string *us;
int status;
struct usb_ep *ep;
struct f_gether_opts *gether_opts;
gether_opts = container_of(f->fi, struct f_gether_opts, func_inst);
/*
* in drivers/usb/gadget/configfs.c:configfs_composite_bind()
* configurations are bound in sequence with list_for_each_entry,
* in each configuration its functions are bound in sequence
* with list_for_each_entry, so we assume no race condition
* with regard to gether_opts->bound access
*/
if (!gether_opts->bound) {
mutex_lock(&gether_opts->lock);
gether_set_gadget(gether_opts->net, cdev->gadget);
status = gether_register_netdev(gether_opts->net);
mutex_unlock(&gether_opts->lock);
if (status)
return status;
gether_opts->bound = true;
}
us = usb_gstrings_attach(cdev, geth_strings,
ARRAY_SIZE(geth_string_defs));
if (IS_ERR(us))
return PTR_ERR(us);
subset_data_intf.iInterface = us[0].id;
ether_desc.iMACAddress = us[1].id;
/* allocate instance-specific interface IDs */
status = usb_interface_id(c, f);
if (status < 0)
goto fail;
subset_data_intf.bInterfaceNumber = status;
status = -ENODEV;
/* allocate instance-specific endpoints */
ep = usb_ep_autoconfig(cdev->gadget, &fs_subset_in_desc);
if (!ep)
goto fail;
geth->port.in_ep = ep;
ep = usb_ep_autoconfig(cdev->gadget, &fs_subset_out_desc);
if (!ep)
goto fail;
geth->port.out_ep = ep;
/* support all relevant hardware speeds... we expect that when
* hardware is dual speed, all bulk-capable endpoints work at
* both speeds
*/
hs_subset_in_desc.bEndpointAddress = fs_subset_in_desc.bEndpointAddress;
hs_subset_out_desc.bEndpointAddress =
fs_subset_out_desc.bEndpointAddress;
ss_subset_in_desc.bEndpointAddress = fs_subset_in_desc.bEndpointAddress;
ss_subset_out_desc.bEndpointAddress =
fs_subset_out_desc.bEndpointAddress;
status = usb_assign_descriptors(f, fs_eth_function, hs_eth_function,
ss_eth_function, ss_eth_function);
if (status)
goto fail;
/* NOTE: all that is done without knowing or caring about
* the network link ... which is unavailable to this code
* until we're activated via set_alt().
*/
DBG(cdev, "CDC Subset: IN/%s OUT/%s\n",
geth->port.in_ep->name, geth->port.out_ep->name);
return 0;
fail:
ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
return status;
}
static inline struct f_gether_opts *to_f_gether_opts(struct config_item *item)
{
return container_of(to_config_group(item), struct f_gether_opts,
func_inst.group);
}
/* f_gether_item_ops */
USB_ETHERNET_CONFIGFS_ITEM(gether);
/* f_gether_opts_dev_addr */
USB_ETHERNET_CONFIGFS_ITEM_ATTR_DEV_ADDR(gether);
/* f_gether_opts_host_addr */
USB_ETHERNET_CONFIGFS_ITEM_ATTR_HOST_ADDR(gether);
/* f_gether_opts_qmult */
USB_ETHERNET_CONFIGFS_ITEM_ATTR_QMULT(gether);
/* f_gether_opts_ifname */
USB_ETHERNET_CONFIGFS_ITEM_ATTR_IFNAME(gether);
static struct configfs_attribute *gether_attrs[] = {
&gether_opts_attr_dev_addr,
&gether_opts_attr_host_addr,
&gether_opts_attr_qmult,
&gether_opts_attr_ifname,
NULL,
};
static const struct config_item_type gether_func_type = {
.ct_item_ops = &gether_item_ops,
.ct_attrs = gether_attrs,
.ct_owner = THIS_MODULE,
};
static void geth_free_inst(struct usb_function_instance *f)
{
struct f_gether_opts *opts;
opts = container_of(f, struct f_gether_opts, func_inst);
if (opts->bound)
gether_cleanup(netdev_priv(opts->net));
else
free_netdev(opts->net);
kfree(opts);
}
static struct usb_function_instance *geth_alloc_inst(void)
{
struct f_gether_opts *opts;
opts = kzalloc(sizeof(*opts), GFP_KERNEL);
if (!opts)
return ERR_PTR(-ENOMEM);
mutex_init(&opts->lock);
opts->func_inst.free_func_inst = geth_free_inst;
opts->net = gether_setup_default();
if (IS_ERR(opts->net)) {
struct net_device *net = opts->net;
kfree(opts);
return ERR_CAST(net);
}
config_group_init_type_name(&opts->func_inst.group, "",
&gether_func_type);
return &opts->func_inst;
}
static void geth_free(struct usb_function *f)
{
struct f_gether *eth;
eth = func_to_geth(f);
kfree(eth);
}
static void geth_unbind(struct usb_configuration *c, struct usb_function *f)
{
geth_string_defs[0].id = 0;
usb_free_all_descriptors(f);
}
static struct usb_function *geth_alloc(struct usb_function_instance *fi)
{
struct f_gether *geth;
struct f_gether_opts *opts;
int status;
/* allocate and initialize one new instance */
geth = kzalloc(sizeof(*geth), GFP_KERNEL);
if (!geth)
return ERR_PTR(-ENOMEM);
opts = container_of(fi, struct f_gether_opts, func_inst);
mutex_lock(&opts->lock);
opts->refcnt++;
/* export host's Ethernet address in CDC format */
status = gether_get_host_addr_cdc(opts->net, geth->ethaddr,
sizeof(geth->ethaddr));
if (status < 12) {
kfree(geth);
mutex_unlock(&opts->lock);
return ERR_PTR(-EINVAL);
}
geth_string_defs[1].s = geth->ethaddr;
geth->port.ioport = netdev_priv(opts->net);
mutex_unlock(&opts->lock);
geth->port.cdc_filter = DEFAULT_FILTER;
geth->port.func.name = "cdc_subset";
geth->port.func.bind = geth_bind;
geth->port.func.unbind = geth_unbind;
geth->port.func.set_alt = geth_set_alt;
geth->port.func.disable = geth_disable;
geth->port.func.free_func = geth_free;
return &geth->port.func;
}
DECLARE_USB_FUNCTION_INIT(geth, geth_alloc_inst, geth_alloc);
MODULE_DESCRIPTION("\"CDC Subset\" Ethernet link function driver");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("David Brownell");
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