USB: gadget: Add EEM gadget driver
This patch adds a CDC EEM ethernet gadget driver. CDC EEM is a newer
USB ethernet specification that uses a simpler interface than the older
CDC ECM. This makes CDC EEM usable by a wider set of USB hardware.
By default the ethernet gadget will still use CDC ECM/Subset, but kernel
configuration and/or a module parameter will allow alternative use of
the CDC EEM protocol.
Changes since last version:
- Brought in missing RNDIS changes that caused compile error
- Modified 'sentinel CRC' checking to match EEM host driver
Signed-off-by: Brian Niebuhr <bniebuhr@efjohnson.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/gadget/f_eem.c b/drivers/usb/gadget/f_eem.c
new file mode 100644
index 0000000..0a577d5
--- /dev/null
+++ b/drivers/usb/gadget/f_eem.c
@@ -0,0 +1,562 @@
+/*
+ * f_eem.c -- USB CDC Ethernet (EEM) link function driver
+ *
+ * Copyright (C) 2003-2005,2008 David Brownell
+ * Copyright (C) 2008 Nokia Corporation
+ * Copyright (C) 2009 EF Johnson Technologies
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/etherdevice.h>
+#include <linux/crc32.h>
+
+#include "u_ether.h"
+
+#define EEM_HLEN 2
+
+/*
+ * This function is a "CDC Ethernet Emulation Model" (CDC EEM)
+ * Ethernet link.
+ */
+
+struct eem_ep_descs {
+ struct usb_endpoint_descriptor *in;
+ struct usb_endpoint_descriptor *out;
+};
+
+struct f_eem {
+ struct gether port;
+ u8 ctrl_id;
+
+ struct eem_ep_descs fs;
+ struct eem_ep_descs hs;
+};
+
+static inline struct f_eem *func_to_eem(struct usb_function *f)
+{
+ return container_of(f, struct f_eem, port.func);
+}
+
+/*-------------------------------------------------------------------------*/
+
+/* interface descriptor: */
+
+static struct usb_interface_descriptor eem_intf __initdata = {
+ .bLength = sizeof eem_intf,
+ .bDescriptorType = USB_DT_INTERFACE,
+
+ /* .bInterfaceNumber = DYNAMIC */
+ .bNumEndpoints = 2,
+ .bInterfaceClass = USB_CLASS_COMM,
+ .bInterfaceSubClass = USB_CDC_SUBCLASS_EEM,
+ .bInterfaceProtocol = USB_CDC_PROTO_EEM,
+ /* .iInterface = DYNAMIC */
+};
+
+/* full speed support: */
+
+static struct usb_endpoint_descriptor eem_fs_in_desc __initdata = {
+ .bLength = USB_DT_ENDPOINT_SIZE,
+ .bDescriptorType = USB_DT_ENDPOINT,
+
+ .bEndpointAddress = USB_DIR_IN,
+ .bmAttributes = USB_ENDPOINT_XFER_BULK,
+};
+
+static struct usb_endpoint_descriptor eem_fs_out_desc __initdata = {
+ .bLength = USB_DT_ENDPOINT_SIZE,
+ .bDescriptorType = USB_DT_ENDPOINT,
+
+ .bEndpointAddress = USB_DIR_OUT,
+ .bmAttributes = USB_ENDPOINT_XFER_BULK,
+};
+
+static struct usb_descriptor_header *eem_fs_function[] __initdata = {
+ /* CDC EEM control descriptors */
+ (struct usb_descriptor_header *) &eem_intf,
+ (struct usb_descriptor_header *) &eem_fs_in_desc,
+ (struct usb_descriptor_header *) &eem_fs_out_desc,
+ NULL,
+};
+
+/* high speed support: */
+
+static struct usb_endpoint_descriptor eem_hs_in_desc __initdata = {
+ .bLength = USB_DT_ENDPOINT_SIZE,
+ .bDescriptorType = USB_DT_ENDPOINT,
+
+ .bEndpointAddress = USB_DIR_IN,
+ .bmAttributes = USB_ENDPOINT_XFER_BULK,
+ .wMaxPacketSize = cpu_to_le16(512),
+};
+
+static struct usb_endpoint_descriptor eem_hs_out_desc __initdata = {
+ .bLength = USB_DT_ENDPOINT_SIZE,
+ .bDescriptorType = USB_DT_ENDPOINT,
+
+ .bEndpointAddress = USB_DIR_OUT,
+ .bmAttributes = USB_ENDPOINT_XFER_BULK,
+ .wMaxPacketSize = cpu_to_le16(512),
+};
+
+static struct usb_descriptor_header *eem_hs_function[] __initdata = {
+ /* CDC EEM control descriptors */
+ (struct usb_descriptor_header *) &eem_intf,
+ (struct usb_descriptor_header *) &eem_hs_in_desc,
+ (struct usb_descriptor_header *) &eem_hs_out_desc,
+ NULL,
+};
+
+/* string descriptors: */
+
+static struct usb_string eem_string_defs[] = {
+ [0].s = "CDC Ethernet Emulation Model (EEM)",
+ { } /* end of list */
+};
+
+static struct usb_gadget_strings eem_string_table = {
+ .language = 0x0409, /* en-us */
+ .strings = eem_string_defs,
+};
+
+static struct usb_gadget_strings *eem_strings[] = {
+ &eem_string_table,
+ NULL,
+};
+
+/*-------------------------------------------------------------------------*/
+
+static int eem_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
+{
+ struct usb_composite_dev *cdev = f->config->cdev;
+ int value = -EOPNOTSUPP;
+ u16 w_index = le16_to_cpu(ctrl->wIndex);
+ u16 w_value = le16_to_cpu(ctrl->wValue);
+ u16 w_length = le16_to_cpu(ctrl->wLength);
+
+ DBG(cdev, "invalid control req%02x.%02x v%04x i%04x l%d\n",
+ ctrl->bRequestType, ctrl->bRequest,
+ w_value, w_index, w_length);
+
+ /* device either stalls (value < 0) or reports success */
+ return value;
+}
+
+
+static int eem_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
+{
+ struct f_eem *eem = func_to_eem(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 (alt != 0)
+ goto fail;
+
+ if (intf == eem->ctrl_id) {
+
+ if (eem->port.in_ep->driver_data) {
+ DBG(cdev, "reset eem\n");
+ gether_disconnect(&eem->port);
+ }
+
+ if (!eem->port.in) {
+ DBG(cdev, "init eem\n");
+ eem->port.in = ep_choose(cdev->gadget,
+ eem->hs.in, eem->fs.in);
+ eem->port.out = ep_choose(cdev->gadget,
+ eem->hs.out, eem->fs.out);
+ }
+
+ /* zlps should not occur because zero-length EEM packets
+ * will be inserted in those cases where they would occur
+ */
+ eem->port.is_zlp_ok = 1;
+ eem->port.cdc_filter = DEFAULT_FILTER;
+ DBG(cdev, "activate eem\n");
+ net = gether_connect(&eem->port);
+ if (IS_ERR(net))
+ return PTR_ERR(net);
+ } else
+ goto fail;
+
+ return 0;
+fail:
+ return -EINVAL;
+}
+
+static void eem_disable(struct usb_function *f)
+{
+ struct f_eem *eem = func_to_eem(f);
+ struct usb_composite_dev *cdev = f->config->cdev;
+
+ DBG(cdev, "eem deactivated\n");
+
+ if (eem->port.in_ep->driver_data)
+ gether_disconnect(&eem->port);
+}
+
+/*-------------------------------------------------------------------------*/
+
+/* EEM function driver setup/binding */
+
+static int __init
+eem_bind(struct usb_configuration *c, struct usb_function *f)
+{
+ struct usb_composite_dev *cdev = c->cdev;
+ struct f_eem *eem = func_to_eem(f);
+ int status;
+ struct usb_ep *ep;
+
+ /* allocate instance-specific interface IDs */
+ status = usb_interface_id(c, f);
+ if (status < 0)
+ goto fail;
+ eem->ctrl_id = status;
+ eem_intf.bInterfaceNumber = status;
+
+ status = -ENODEV;
+
+ /* allocate instance-specific endpoints */
+ ep = usb_ep_autoconfig(cdev->gadget, &eem_fs_in_desc);
+ if (!ep)
+ goto fail;
+ eem->port.in_ep = ep;
+ ep->driver_data = cdev; /* claim */
+
+ ep = usb_ep_autoconfig(cdev->gadget, &eem_fs_out_desc);
+ if (!ep)
+ goto fail;
+ eem->port.out_ep = ep;
+ ep->driver_data = cdev; /* claim */
+
+ status = -ENOMEM;
+
+ /* copy descriptors, and track endpoint copies */
+ f->descriptors = usb_copy_descriptors(eem_fs_function);
+ if (!f->descriptors)
+ goto fail;
+
+ eem->fs.in = usb_find_endpoint(eem_fs_function,
+ f->descriptors, &eem_fs_in_desc);
+ eem->fs.out = usb_find_endpoint(eem_fs_function,
+ f->descriptors, &eem_fs_out_desc);
+
+ /* support all relevant hardware speeds... we expect that when
+ * hardware is dual speed, all bulk-capable endpoints work at
+ * both speeds
+ */
+ if (gadget_is_dualspeed(c->cdev->gadget)) {
+ eem_hs_in_desc.bEndpointAddress =
+ eem_fs_in_desc.bEndpointAddress;
+ eem_hs_out_desc.bEndpointAddress =
+ eem_fs_out_desc.bEndpointAddress;
+
+ /* copy descriptors, and track endpoint copies */
+ f->hs_descriptors = usb_copy_descriptors(eem_hs_function);
+ if (!f->hs_descriptors)
+ goto fail;
+
+ eem->hs.in = usb_find_endpoint(eem_hs_function,
+ f->hs_descriptors, &eem_hs_in_desc);
+ eem->hs.out = usb_find_endpoint(eem_hs_function,
+ f->hs_descriptors, &eem_hs_out_desc);
+ }
+
+ DBG(cdev, "CDC Ethernet (EEM): %s speed IN/%s OUT/%s\n",
+ gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
+ eem->port.in_ep->name, eem->port.out_ep->name);
+ return 0;
+
+fail:
+ if (f->descriptors)
+ usb_free_descriptors(f->descriptors);
+
+ /* we might as well release our claims on endpoints */
+ if (eem->port.out)
+ eem->port.out_ep->driver_data = NULL;
+ if (eem->port.in)
+ eem->port.in_ep->driver_data = NULL;
+
+ ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
+
+ return status;
+}
+
+static void
+eem_unbind(struct usb_configuration *c, struct usb_function *f)
+{
+ struct f_eem *eem = func_to_eem(f);
+
+ DBG(c->cdev, "eem unbind\n");
+
+ if (gadget_is_dualspeed(c->cdev->gadget))
+ usb_free_descriptors(f->hs_descriptors);
+ usb_free_descriptors(f->descriptors);
+ kfree(eem);
+}
+
+static void eem_cmd_complete(struct usb_ep *ep, struct usb_request *req)
+{
+}
+
+/*
+ * Add the EEM header and ethernet checksum.
+ * We currently do not attempt to put multiple ethernet frames
+ * into a single USB transfer
+ */
+static struct sk_buff *eem_wrap(struct gether *port, struct sk_buff *skb)
+{
+ struct sk_buff *skb2 = NULL;
+ struct usb_ep *in = port->in_ep;
+ int padlen = 0;
+ u16 len = skb->len;
+
+ if (!skb_cloned(skb)) {
+ int headroom = skb_headroom(skb);
+ int tailroom = skb_tailroom(skb);
+
+ /* When (len + EEM_HLEN + ETH_FCS_LEN) % in->maxpacket) is 0,
+ * stick two bytes of zero-length EEM packet on the end.
+ */
+ if (((len + EEM_HLEN + ETH_FCS_LEN) % in->maxpacket) == 0)
+ padlen += 2;
+
+ if ((tailroom >= (ETH_FCS_LEN + padlen)) &&
+ (headroom >= EEM_HLEN))
+ goto done;
+ }
+
+ skb2 = skb_copy_expand(skb, EEM_HLEN, ETH_FCS_LEN + padlen, GFP_ATOMIC);
+ dev_kfree_skb_any(skb);
+ skb = skb2;
+ if (!skb)
+ return skb;
+
+done:
+ /* use the "no CRC" option */
+ put_unaligned_be32(0xdeadbeef, skb_put(skb, 4));
+
+ /* EEM packet header format:
+ * b0..13: length of ethernet frame
+ * b14: bmCRC (0 == sentinel CRC)
+ * b15: bmType (0 == data)
+ */
+ len = skb->len;
+ put_unaligned_le16((len & 0x3FFF) | BIT(14), skb_push(skb, 2));
+
+ /* add a zero-length EEM packet, if needed */
+ if (padlen)
+ put_unaligned_le16(0, skb_put(skb, 2));
+
+ return skb;
+}
+
+/*
+ * Remove the EEM header. Note that there can be many EEM packets in a single
+ * USB transfer, so we need to break them out and handle them independently.
+ */
+static int eem_unwrap(struct gether *port,
+ struct sk_buff *skb,
+ struct sk_buff_head *list)
+{
+ struct usb_composite_dev *cdev = port->func.config->cdev;
+ int status = 0;
+
+ do {
+ struct sk_buff *skb2;
+ u16 header;
+ u16 len = 0;
+
+ if (skb->len < EEM_HLEN) {
+ status = -EINVAL;
+ DBG(cdev, "invalid EEM header\n");
+ goto error;
+ }
+
+ /* remove the EEM header */
+ header = get_unaligned_le16(skb->data);
+ skb_pull(skb, EEM_HLEN);
+
+ /* EEM packet header format:
+ * b0..14: EEM type dependent (data or command)
+ * b15: bmType (0 == data, 1 == command)
+ */
+ if (header & BIT(15)) {
+ struct usb_request *req = cdev->req;
+ u16 bmEEMCmd;
+
+ /* EEM command packet format:
+ * b0..10: bmEEMCmdParam
+ * b11..13: bmEEMCmd
+ * b14: reserved (must be zero)
+ * b15: bmType (1 == command)
+ */
+ if (header & BIT(14))
+ continue;
+
+ bmEEMCmd = (header >> 11) & 0x7;
+ switch (bmEEMCmd) {
+ case 0: /* echo */
+ len = header & 0x7FF;
+ if (skb->len < len) {
+ status = -EOVERFLOW;
+ goto error;
+ }
+
+ skb2 = skb_clone(skb, GFP_ATOMIC);
+ if (unlikely(!skb2)) {
+ DBG(cdev, "EEM echo response error\n");
+ goto next;
+ }
+ skb_trim(skb2, len);
+ put_unaligned_le16(BIT(15) | BIT(11) | len,
+ skb_push(skb2, 2));
+ skb_copy_bits(skb, 0, req->buf, skb->len);
+ req->length = skb->len;
+ req->complete = eem_cmd_complete;
+ req->zero = 1;
+ if (usb_ep_queue(port->in_ep, req, GFP_ATOMIC))
+ DBG(cdev, "echo response queue fail\n");
+ break;
+
+ case 1: /* echo response */
+ case 2: /* suspend hint */
+ case 3: /* response hint */
+ case 4: /* response complete hint */
+ case 5: /* tickle */
+ default: /* reserved */
+ continue;
+ }
+ } else {
+ u32 crc, crc2;
+ struct sk_buff *skb3;
+
+ /* check for zero-length EEM packet */
+ if (header == 0)
+ continue;
+
+ /* EEM data packet format:
+ * b0..13: length of ethernet frame
+ * b14: bmCRC (0 == sentinel, 1 == calculated)
+ * b15: bmType (0 == data)
+ */
+ len = header & 0x3FFF;
+ if ((skb->len < len)
+ || (len < (ETH_HLEN + ETH_FCS_LEN))) {
+ status = -EINVAL;
+ goto error;
+ }
+
+ /* validate CRC */
+ crc = get_unaligned_le32(skb->data + len - ETH_FCS_LEN);
+ if (header & BIT(14)) {
+ crc = get_unaligned_le32(skb->data + len
+ - ETH_FCS_LEN);
+ crc2 = ~crc32_le(~0,
+ skb->data,
+ skb->len - ETH_FCS_LEN);
+ } else {
+ crc = get_unaligned_be32(skb->data + len
+ - ETH_FCS_LEN);
+ crc2 = 0xdeadbeef;
+ }
+ if (crc != crc2) {
+ DBG(cdev, "invalid EEM CRC\n");
+ goto next;
+ }
+
+ skb2 = skb_clone(skb, GFP_ATOMIC);
+ if (unlikely(!skb2)) {
+ DBG(cdev, "unable to unframe EEM packet\n");
+ continue;
+ }
+ skb_trim(skb2, len - ETH_FCS_LEN);
+
+ skb3 = skb_copy_expand(skb2,
+ NET_IP_ALIGN,
+ 0,
+ GFP_ATOMIC);
+ if (unlikely(!skb3)) {
+ DBG(cdev, "unable to realign EEM packet\n");
+ dev_kfree_skb_any(skb2);
+ continue;
+ }
+ dev_kfree_skb_any(skb2);
+ skb_queue_tail(list, skb3);
+ }
+next:
+ skb_pull(skb, len);
+ } while (skb->len);
+
+error:
+ dev_kfree_skb_any(skb);
+ return status;
+}
+
+/**
+ * eem_bind_config - add CDC Ethernet (EEM) network link to a configuration
+ * @c: the configuration to support the network link
+ * Context: single threaded during gadget setup
+ *
+ * Returns zero on success, else negative errno.
+ *
+ * Caller must have called @gether_setup(). Caller is also responsible
+ * for calling @gether_cleanup() before module unload.
+ */
+int __init eem_bind_config(struct usb_configuration *c)
+{
+ struct f_eem *eem;
+ int status;
+
+ /* maybe allocate device-global string IDs */
+ if (eem_string_defs[0].id == 0) {
+
+ /* control interface label */
+ status = usb_string_id(c->cdev);
+ if (status < 0)
+ return status;
+ eem_string_defs[0].id = status;
+ eem_intf.iInterface = status;
+ }
+
+ /* allocate and initialize one new instance */
+ eem = kzalloc(sizeof *eem, GFP_KERNEL);
+ if (!eem)
+ return -ENOMEM;
+
+ eem->port.cdc_filter = DEFAULT_FILTER;
+
+ eem->port.func.name = "cdc_eem";
+ eem->port.func.strings = eem_strings;
+ /* descriptors are per-instance copies */
+ eem->port.func.bind = eem_bind;
+ eem->port.func.unbind = eem_unbind;
+ eem->port.func.set_alt = eem_set_alt;
+ eem->port.func.setup = eem_setup;
+ eem->port.func.disable = eem_disable;
+ eem->port.wrap = eem_wrap;
+ eem->port.unwrap = eem_unwrap;
+ eem->port.header_len = EEM_HLEN;
+
+ status = usb_add_function(c, &eem->port.func);
+ if (status)
+ kfree(eem);
+ return status;
+}
+