From bfe9b3f8c5229e5de4fd18e941866bc410d16334 Mon Sep 17 00:00:00 2001 From: Ben Chan Date: Wed, 19 Mar 2014 14:00:05 -0700 Subject: [PATCH 1/2] USB: cdc: add MBIM extended functional descriptor structure This patch adds the MBIM extended functional descriptor structure defined in "Universal Serial Bus Communications Class Subclass Specification for Mobile Broadband Interface Model, Revision 1.0, Errata-1" published by USB-IF. Signed-off-by: Ben Chan Acked-by: Greg Kroah-Hartman Signed-off-by: David S. Miller --- include/uapi/linux/usb/cdc.h | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/include/uapi/linux/usb/cdc.h b/include/uapi/linux/usb/cdc.h index f35aa0a338c7..b6a9cdd6e096 100644 --- a/include/uapi/linux/usb/cdc.h +++ b/include/uapi/linux/usb/cdc.h @@ -56,6 +56,7 @@ #define USB_CDC_OBEX_TYPE 0x15 #define USB_CDC_NCM_TYPE 0x1a #define USB_CDC_MBIM_TYPE 0x1b +#define USB_CDC_MBIM_EXTENDED_TYPE 0x1c /* "Header Functional Descriptor" from CDC spec 5.2.3.1 */ struct usb_cdc_header_desc { @@ -205,6 +206,17 @@ struct usb_cdc_mbim_desc { __u8 bmNetworkCapabilities; } __attribute__ ((packed)); +/* "MBIM Extended Functional Descriptor" from CDC MBIM spec 1.0 errata-1 */ +struct usb_cdc_mbim_extended_desc { + __u8 bLength; + __u8 bDescriptorType; + __u8 bDescriptorSubType; + + __le16 bcdMBIMExtendedVersion; + __u8 bMaxOutstandingCommandMessages; + __le16 wMTU; +} __attribute__ ((packed)); + /*-------------------------------------------------------------------------*/ /* From 259fef033ffe4e70bf7f358c53400a09f1b5384e Mon Sep 17 00:00:00 2001 From: Ben Chan Date: Wed, 19 Mar 2014 14:00:06 -0700 Subject: [PATCH 2/2] net: cdc_ncm: respect operator preferred MTU reported by MBIM According to "Universal Serial Bus Communications Class Subclass Specification for Mobile Broadband Interface Model, Revision 1.0, Errata-1" published by USB-IF, the wMTU field of the MBIM extended functional descriptor indicates the operator preferred MTU for IP data streams. This patch modifies cdc_ncm_setup to ensure that the MTU value set on the usbnet device does not exceed the operator preferred MTU indicated by wMTU if the MBIM device exposes a MBIM extended functional descriptor. Signed-off-by: Ben Chan Signed-off-by: David S. Miller --- drivers/net/usb/cdc_ncm.c | 17 +++++++++++++++++ include/linux/usb/cdc_ncm.h | 1 + 2 files changed, 18 insertions(+) diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c index dbff290ed0e4..e8711a8cfa01 100644 --- a/drivers/net/usb/cdc_ncm.c +++ b/drivers/net/usb/cdc_ncm.c @@ -74,6 +74,7 @@ static int cdc_ncm_setup(struct usbnet *dev) u8 iface_no; int err; int eth_hlen; + u16 mbim_mtu; u16 ntb_fmt_supported; __le16 max_datagram_size; @@ -261,6 +262,14 @@ out: /* set MTU to max supported by the device if necessary */ if (dev->net->mtu > ctx->max_datagram_size - eth_hlen) dev->net->mtu = ctx->max_datagram_size - eth_hlen; + + /* do not exceed operater preferred MTU */ + if (ctx->mbim_extended_desc) { + mbim_mtu = le16_to_cpu(ctx->mbim_extended_desc->wMTU); + if (mbim_mtu != 0 && mbim_mtu < dev->net->mtu) + dev->net->mtu = mbim_mtu; + } + return 0; } @@ -399,6 +408,14 @@ int cdc_ncm_bind_common(struct usbnet *dev, struct usb_interface *intf, u8 data_ ctx->mbim_desc = (const struct usb_cdc_mbim_desc *)buf; break; + case USB_CDC_MBIM_EXTENDED_TYPE: + if (buf[0] < sizeof(*(ctx->mbim_extended_desc))) + break; + + ctx->mbim_extended_desc = + (const struct usb_cdc_mbim_extended_desc *)buf; + break; + default: break; } diff --git a/include/linux/usb/cdc_ncm.h b/include/linux/usb/cdc_ncm.h index c3fa80745996..bdf05fb36729 100644 --- a/include/linux/usb/cdc_ncm.h +++ b/include/linux/usb/cdc_ncm.h @@ -93,6 +93,7 @@ struct cdc_ncm_ctx { const struct usb_cdc_ncm_desc *func_desc; const struct usb_cdc_mbim_desc *mbim_desc; + const struct usb_cdc_mbim_extended_desc *mbim_extended_desc; const struct usb_cdc_ether_desc *ether_desc; struct usb_interface *control;