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net: cdc_ncm, cdc_mbim: allow user to prefer NCM for backwards compatibility

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commit bd329e1 ("net: cdc_ncm: do not bind to NCM compatible MBIM devices")
introduced a new policy, preferring MBIM for dual NCM/MBIM functions if
the cdc_mbim driver was enabled.  This caused a regression for users
wanting to use NCM.

Devices implementing NCM backwards compatibility according to section
3.2 of the MBIM v1.0 specification allow either NCM or MBIM on a single
USB function, using different altsettings.  The cdc_ncm and cdc_mbim
drivers will both probe such functions, and must agree on a common
policy for selecting either MBIM or NCM.  Until now, this policy has
been set at build time based on CONFIG_USB_NET_CDC_MBIM.

Use a module parameter to set the system policy at runtime, allowing the
user to prefer NCM on systems with the cdc_mbim driver.

Cc: Greg Suarez <gsuarez@smithmicro.com>
Cc: Alexey Orishko <alexey.orishko@stericsson.com>
Reported-by: Geir Haatveit <nospam@haatveit.nu>
Reported-by: Tommi Kyntola <kynde@ts.ray.fi>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=54791
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Bjørn Mork 2013-03-14 01:05:13 +00:00 committed by David S. Miller
parent a5b8db9144
commit 1e8bbe6cd0
3 changed files with 34 additions and 27 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
drivers/net/usb/cdc_mbim.c
View File

@ -68,18 +68,9 @@ static int cdc_mbim_bind(struct usbnet *dev, struct usb_interface *intf)
struct cdc_ncm_ctx *ctx;
struct usb_driver *subdriver = ERR_PTR(-ENODEV);
int ret = -ENODEV;
u8 data_altsetting = CDC_NCM_DATA_ALTSETTING_NCM;
u8 data_altsetting = cdc_ncm_select_altsetting(dev, intf);
struct cdc_mbim_state *info = (void *)&dev->data;
/* see if interface supports MBIM alternate setting */
if (intf->num_altsetting == 2) {
if (!cdc_ncm_comm_intf_is_mbim(intf->cur_altsetting))
usb_set_interface(dev->udev,
intf->cur_altsetting->desc.bInterfaceNumber,
CDC_NCM_COMM_ALTSETTING_MBIM);
data_altsetting = CDC_NCM_DATA_ALTSETTING_MBIM;
}
/* Probably NCM, defer for cdc_ncm_bind */
if (!cdc_ncm_comm_intf_is_mbim(intf->cur_altsetting))
goto err;

49
drivers/net/usb/cdc_ncm.c
View File

@ -55,6 +55,14 @@
#define DRIVER_VERSION "14-Mar-2012"
#if IS_ENABLED(CONFIG_USB_NET_CDC_MBIM)
static bool prefer_mbim = true;
#else
static bool prefer_mbim;
#endif
module_param(prefer_mbim, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(prefer_mbim, "Prefer MBIM setting on dual NCM/MBIM functions");
static void cdc_ncm_txpath_bh(unsigned long param);
static void cdc_ncm_tx_timeout_start(struct cdc_ncm_ctx *ctx);
static enum hrtimer_restart cdc_ncm_tx_timer_cb(struct hrtimer *hr_timer);
@ -550,9 +558,12 @@ void cdc_ncm_unbind(struct usbnet *dev, struct usb_interface *intf)
}
EXPORT_SYMBOL_GPL(cdc_ncm_unbind);
static int cdc_ncm_bind(struct usbnet *dev, struct usb_interface *intf)
/* Select the MBIM altsetting iff it is preferred and available,
* returning the number of the corresponding data interface altsetting
*/
u8 cdc_ncm_select_altsetting(struct usbnet *dev, struct usb_interface *intf)
{
int ret;
struct usb_host_interface *alt;
/* The MBIM spec defines a NCM compatible default altsetting,
* which we may have matched:
@ -568,23 +579,27 @@ static int cdc_ncm_bind(struct usbnet *dev, struct usb_interface *intf)
* endpoint descriptors, shall be constructed according to
* the rules given in section 6 (USB Device Model) of this
* specification."
*
* Do not bind to such interfaces, allowing cdc_mbim to handle
* them
*/
#if IS_ENABLED(CONFIG_USB_NET_CDC_MBIM)
if ((intf->num_altsetting == 2) &&
!usb_set_interface(dev->udev,
intf->cur_altsetting->desc.bInterfaceNumber,
CDC_NCM_COMM_ALTSETTING_MBIM)) {
if (cdc_ncm_comm_intf_is_mbim(intf->cur_altsetting))
return -ENODEV;
else
usb_set_interface(dev->udev,
intf->cur_altsetting->desc.bInterfaceNumber,
CDC_NCM_COMM_ALTSETTING_NCM);
if (prefer_mbim && intf->num_altsetting == 2) {
alt = usb_altnum_to_altsetting(intf, CDC_NCM_COMM_ALTSETTING_MBIM);
if (alt && cdc_ncm_comm_intf_is_mbim(alt) &&
!usb_set_interface(dev->udev,
intf->cur_altsetting->desc.bInterfaceNumber,
CDC_NCM_COMM_ALTSETTING_MBIM))
return CDC_NCM_DATA_ALTSETTING_MBIM;
}
#endif
return CDC_NCM_DATA_ALTSETTING_NCM;
}
EXPORT_SYMBOL_GPL(cdc_ncm_select_altsetting);
static int cdc_ncm_bind(struct usbnet *dev, struct usb_interface *intf)
{
int ret;
/* MBIM backwards compatible function? */
cdc_ncm_select_altsetting(dev, intf);
if (cdc_ncm_comm_intf_is_mbim(intf->cur_altsetting))
return -ENODEV;
/* NCM data altsetting is always 1 */
ret = cdc_ncm_bind_common(dev, intf, 1);

1
include/linux/usb/cdc_ncm.h
View File

@ -127,6 +127,7 @@ struct cdc_ncm_ctx {
u16 connected;
};
extern u8 cdc_ncm_select_altsetting(struct usbnet *dev, struct usb_interface *intf);
extern int cdc_ncm_bind_common(struct usbnet *dev, struct usb_interface *intf, u8 data_altsetting);
extern void cdc_ncm_unbind(struct usbnet *dev, struct usb_interface *intf);
extern struct sk_buff *cdc_ncm_fill_tx_frame(struct cdc_ncm_ctx *ctx, struct sk_buff *skb, __le32 sign);