From 1e8bbe6cd02fc300c88bd48244ce61ad9c7d1776 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Bj=C3=B8rn=20Mork?= Date: Thu, 14 Mar 2013 01:05:13 +0000 Subject: [PATCH] net: cdc_ncm, cdc_mbim: allow user to prefer NCM for backwards compatibility MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Cc: Alexey Orishko Reported-by: Geir Haatveit Reported-by: Tommi Kyntola Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=54791 Signed-off-by: Bjørn Mork Signed-off-by: David S. Miller --- drivers/net/usb/cdc_mbim.c | 11 +-------- drivers/net/usb/cdc_ncm.c | 49 ++++++++++++++++++++++++------------- include/linux/usb/cdc_ncm.h | 1 + 3 files changed, 34 insertions(+), 27 deletions(-) diff --git a/drivers/net/usb/cdc_mbim.c b/drivers/net/usb/cdc_mbim.c index 248d2dc765a5..16c842997291 100644 --- a/drivers/net/usb/cdc_mbim.c +++ b/drivers/net/usb/cdc_mbim.c @@ -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; diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c index 61b74a2b89ac..4709fa3497cf 100644 --- a/drivers/net/usb/cdc_ncm.c +++ b/drivers/net/usb/cdc_ncm.c @@ -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); diff --git a/include/linux/usb/cdc_ncm.h b/include/linux/usb/cdc_ncm.h index 3b8f9d4fc3fe..cc25b70af33c 100644 --- a/include/linux/usb/cdc_ncm.h +++ b/include/linux/usb/cdc_ncm.h @@ -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); -- 2.20.1