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|
/*
* Copyright (c) 2012 Bjørn Mork <bjorn@mork.no>
*
* The probing code is heavily inspired by cdc_ether, which is:
* Copyright (C) 2003-2005 by David Brownell
* Copyright (C) 2006 by Ole Andre Vadla Ravnas (ActiveSync)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* version 2 as published by the Free Software Foundation.
*/
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/ethtool.h>
#include <linux/mii.h>
#include <linux/usb.h>
#include <linux/usb/cdc.h>
#include <linux/usb/usbnet.h>
#include <linux/usb/cdc-wdm.h>
/* This driver supports wwan (3G/LTE/?) devices using a vendor
* specific management protocol called Qualcomm MSM Interface (QMI) -
* in addition to the more common AT commands over serial interface
* management
*
* QMI is wrapped in CDC, using CDC encapsulated commands on the
* control ("master") interface of a two-interface CDC Union
* resembling standard CDC ECM. The devices do not use the control
* interface for any other CDC messages. Most likely because the
* management protocol is used in place of the standard CDC
* notifications NOTIFY_NETWORK_CONNECTION and NOTIFY_SPEED_CHANGE
*
* Alternatively, control and data functions can be combined in a
* single USB interface.
*
* Handling a protocol like QMI is out of the scope for any driver.
* It is exported as a character device using the cdc-wdm driver as
* a subdriver, enabling userspace applications ("modem managers") to
* handle it.
*
* These devices may alternatively/additionally be configured using AT
* commands on a serial interface
*/
/* driver specific data */
struct qmi_wwan_state {
struct usb_driver *subdriver;
atomic_t pmcount;
unsigned long unused;
struct usb_interface *control;
struct usb_interface *data;
};
/* using a counter to merge subdriver requests with our own into a combined state */
static int qmi_wwan_manage_power(struct usbnet *dev, int on)
{
struct qmi_wwan_state *info = (void *)&dev->data;
int rv = 0;
dev_dbg(&dev->intf->dev, "%s() pmcount=%d, on=%d\n", __func__, atomic_read(&info->pmcount), on);
if ((on && atomic_add_return(1, &info->pmcount) == 1) || (!on && atomic_dec_and_test(&info->pmcount))) {
/* need autopm_get/put here to ensure the usbcore sees the new value */
rv = usb_autopm_get_interface(dev->intf);
if (rv < 0)
goto err;
dev->intf->needs_remote_wakeup = on;
usb_autopm_put_interface(dev->intf);
}
err:
return rv;
}
static int qmi_wwan_cdc_wdm_manage_power(struct usb_interface *intf, int on)
{
struct usbnet *dev = usb_get_intfdata(intf);
/* can be called while disconnecting */
if (!dev)
return 0;
return qmi_wwan_manage_power(dev, on);
}
/* collect all three endpoints and register subdriver */
static int qmi_wwan_register_subdriver(struct usbnet *dev)
{
int rv;
struct usb_driver *subdriver = NULL;
struct qmi_wwan_state *info = (void *)&dev->data;
/* collect bulk endpoints */
rv = usbnet_get_endpoints(dev, info->data);
if (rv < 0)
goto err;
/* update status endpoint if separate control interface */
if (info->control != info->data)
dev->status = &info->control->cur_altsetting->endpoint[0];
/* require interrupt endpoint for subdriver */
if (!dev->status) {
rv = -EINVAL;
goto err;
}
/* for subdriver power management */
atomic_set(&info->pmcount, 0);
/* register subdriver */
subdriver = usb_cdc_wdm_register(info->control, &dev->status->desc, 512, &qmi_wwan_cdc_wdm_manage_power);
if (IS_ERR(subdriver)) {
dev_err(&info->control->dev, "subdriver registration failed\n");
rv = PTR_ERR(subdriver);
goto err;
}
/* prevent usbnet from using status endpoint */
dev->status = NULL;
/* save subdriver struct for suspend/resume wrappers */
info->subdriver = subdriver;
err:
return rv;
}
static int qmi_wwan_bind(struct usbnet *dev, struct usb_interface *intf)
{
int status = -1;
u8 *buf = intf->cur_altsetting->extra;
int len = intf->cur_altsetting->extralen;
struct usb_interface_descriptor *desc = &intf->cur_altsetting->desc;
struct usb_cdc_union_desc *cdc_union = NULL;
struct usb_cdc_ether_desc *cdc_ether = NULL;
u32 found = 0;
struct usb_driver *driver = driver_of(intf);
struct qmi_wwan_state *info = (void *)&dev->data;
BUILD_BUG_ON((sizeof(((struct usbnet *)0)->data) < sizeof(struct qmi_wwan_state)));
/* require a single interrupt status endpoint for subdriver */
if (intf->cur_altsetting->desc.bNumEndpoints != 1)
goto err;
while (len > 3) {
struct usb_descriptor_header *h = (void *)buf;
/* ignore any misplaced descriptors */
if (h->bDescriptorType != USB_DT_CS_INTERFACE)
goto next_desc;
/* buf[2] is CDC descriptor subtype */
switch (buf[2]) {
case USB_CDC_HEADER_TYPE:
if (found & 1 << USB_CDC_HEADER_TYPE) {
dev_dbg(&intf->dev, "extra CDC header\n");
goto err;
}
if (h->bLength != sizeof(struct usb_cdc_header_desc)) {
dev_dbg(&intf->dev, "CDC header len %u\n", h->bLength);
goto err;
}
break;
case USB_CDC_UNION_TYPE:
if (found & 1 << USB_CDC_UNION_TYPE) {
dev_dbg(&intf->dev, "extra CDC union\n");
goto err;
}
if (h->bLength != sizeof(struct usb_cdc_union_desc)) {
dev_dbg(&intf->dev, "CDC union len %u\n", h->bLength);
goto err;
}
cdc_union = (struct usb_cdc_union_desc *)buf;
break;
case USB_CDC_ETHERNET_TYPE:
if (found & 1 << USB_CDC_ETHERNET_TYPE) {
dev_dbg(&intf->dev, "extra CDC ether\n");
goto err;
}
if (h->bLength != sizeof(struct usb_cdc_ether_desc)) {
dev_dbg(&intf->dev, "CDC ether len %u\n", h->bLength);
goto err;
}
cdc_ether = (struct usb_cdc_ether_desc *)buf;
break;
}
/*
* Remember which CDC functional descriptors we've seen. Works
* for all types we care about, of which USB_CDC_ETHERNET_TYPE
* (0x0f) is the highest numbered
*/
if (buf[2] < 32)
found |= 1 << buf[2];
next_desc:
len -= h->bLength;
buf += h->bLength;
}
/* did we find all the required ones? */
if (!(found & (1 << USB_CDC_HEADER_TYPE)) ||
!(found & (1 << USB_CDC_UNION_TYPE))) {
dev_err(&intf->dev, "CDC functional descriptors missing\n");
goto err;
}
/* verify CDC Union */
if (desc->bInterfaceNumber != cdc_union->bMasterInterface0) {
dev_err(&intf->dev, "bogus CDC Union: master=%u\n", cdc_union->bMasterInterface0);
goto err;
}
/* need to save these for unbind */
info->control = intf;
info->data = usb_ifnum_to_if(dev->udev, cdc_union->bSlaveInterface0);
if (!info->data) {
dev_err(&intf->dev, "bogus CDC Union: slave=%u\n", cdc_union->bSlaveInterface0);
goto err;
}
/* errors aren't fatal - we can live with the dynamic address */
if (cdc_ether) {
dev->hard_mtu = le16_to_cpu(cdc_ether->wMaxSegmentSize);
usbnet_get_ethernet_addr(dev, cdc_ether->iMACAddress);
}
/* claim data interface and set it up */
status = usb_driver_claim_interface(driver, info->data, dev);
if (status < 0)
goto err;
|