diff options
Diffstat (limited to 'drivers/usb/gadget/function/f_subset.c')
| -rw-r--r-- | drivers/usb/gadget/function/f_subset.c | 506 |
1 files changed, 506 insertions, 0 deletions
diff --git a/drivers/usb/gadget/function/f_subset.c b/drivers/usb/gadget/function/f_subset.c new file mode 100644 index 000000000..51c1cae16 --- /dev/null +++ b/drivers/usb/gadget/function/f_subset.c @@ -0,0 +1,506 @@ +// 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: %s speed IN/%s OUT/%s\n", + gadget_is_superspeed(c->cdev->gadget) ? "super" : + gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full", + 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_LICENSE("GPL"); +MODULE_AUTHOR("David Brownell"); |