diff options
| -rw-r--r-- | Documentation/usb/gadget-testing.rst | 20 | ||||
| -rw-r--r-- | drivers/usb/gadget/function/f_ncm.c | 69 | ||||
| -rw-r--r-- | drivers/usb/gadget/function/u_ncm.h | 2 |
3 files changed, 79 insertions, 12 deletions
diff --git a/Documentation/usb/gadget-testing.rst b/Documentation/usb/gadget-testing.rst index 29072c166d23..8cd62c466d20 100644 --- a/Documentation/usb/gadget-testing.rst +++ b/Documentation/usb/gadget-testing.rst @@ -448,15 +448,17 @@ Function-specific configfs interface The function name to use when creating the function directory is "ncm". The NCM function provides these attributes in its function directory: - =============== ================================================== - ifname network device interface name associated with this - function instance - qmult queue length multiplier for high and super speed - host_addr MAC address of host's end of this - Ethernet over USB link - dev_addr MAC address of device's end of this - Ethernet over USB link - =============== ================================================== + =============== ================================================== + ifname network device interface name associated with this + function instance + qmult queue length multiplier for high and super speed + host_addr MAC address of host's end of this + Ethernet over USB link + dev_addr MAC address of device's end of this + Ethernet over USB link + max_segment_size Segment size required for P2P connections. This + will set MTU to (max_segment_size - 14 bytes) + =============== ================================================== and after creating the functions/ncm.<instance name> they contain default values: qmult is 5, dev_addr and host_addr are randomly selected. diff --git a/drivers/usb/gadget/function/f_ncm.c b/drivers/usb/gadget/function/f_ncm.c index cc0ed29a4adc..a1575a0ca568 100644 --- a/drivers/usb/gadget/function/f_ncm.c +++ b/drivers/usb/gadget/function/f_ncm.c @@ -103,6 +103,16 @@ static inline struct f_ncm *func_to_ncm(struct usb_function *f) /* Delay for the transmit to wait before sending an unfilled NTB frame. */ #define TX_TIMEOUT_NSECS 300000 +/* + * Although max mtu as dictated by u_ether is 15412 bytes, setting + * max_segment_sizeto 15426 would not be efficient. If user chooses segment + * size to be (>= 8192), then we can't aggregate more than one buffer in each + * NTB (assuming each packet coming from network layer is >= 8192 bytes) as ep + * maxpacket limit is 16384. So let max_segment_size be limited to 8000 to allow + * at least 2 packets to be aggregated reducing wastage of NTB buffer space + */ +#define MAX_DATAGRAM_SIZE 8000 + #define FORMATS_SUPPORTED (USB_CDC_NCM_NTB16_SUPPORTED | \ USB_CDC_NCM_NTB32_SUPPORTED) @@ -179,7 +189,6 @@ static struct usb_cdc_ether_desc ecm_desc = { /* this descriptor actually adds value, surprise! */ /* .iMACAddress = DYNAMIC */ .bmEthernetStatistics = cpu_to_le32(0), /* no statistics */ - .wMaxSegmentSize = cpu_to_le16(ETH_FRAME_LEN), .wNumberMCFilters = cpu_to_le16(0), .bNumberPowerFilters = 0, }; @@ -1166,11 +1175,15 @@ static int ncm_unwrap_ntb(struct gether *port, struct sk_buff *skb2; int ret = -EINVAL; unsigned ntb_max = le32_to_cpu(ntb_parameters.dwNtbOutMaxSize); - unsigned frame_max = le16_to_cpu(ecm_desc.wMaxSegmentSize); + unsigned frame_max; const struct ndp_parser_opts *opts = ncm->parser_opts; unsigned crc_len = ncm->is_crc ? sizeof(uint32_t) : 0; int dgram_counter; int to_process = skb->len; + struct f_ncm_opts *ncm_opts; + + ncm_opts = container_of(port->func.fi, struct f_ncm_opts, func_inst); + frame_max = ncm_opts->max_segment_size; parse_ntb: tmp = (__le16 *)ntb_ptr; @@ -1430,8 +1443,10 @@ static int ncm_bind(struct usb_configuration *c, struct usb_function *f) mutex_lock(&ncm_opts->lock); gether_set_gadget(ncm_opts->net, cdev->gadget); - if (!ncm_opts->bound) + if (!ncm_opts->bound) { + ncm_opts->net->mtu = (ncm_opts->max_segment_size - ETH_HLEN); status = gether_register_netdev(ncm_opts->net); + } mutex_unlock(&ncm_opts->lock); if (status) @@ -1474,6 +1489,8 @@ static int ncm_bind(struct usb_configuration *c, struct usb_function *f) ncm_data_intf.bInterfaceNumber = status; ncm_union_desc.bSlaveInterface0 = status; + ecm_desc.wMaxSegmentSize = ncm_opts->max_segment_size; + status = -ENODEV; /* allocate instance-specific endpoints */ @@ -1576,11 +1593,56 @@ USB_ETHERNET_CONFIGFS_ITEM_ATTR_QMULT(ncm); /* f_ncm_opts_ifname */ USB_ETHERNET_CONFIGFS_ITEM_ATTR_IFNAME(ncm); +static ssize_t ncm_opts_max_segment_size_show(struct config_item *item, + char *page) +{ + struct f_ncm_opts *opts = to_f_ncm_opts(item); + u16 segment_size; + + mutex_lock(&opts->lock); + segment_size = opts->max_segment_size; + mutex_unlock(&opts->lock); + + return sysfs_emit(page, "%u\n", segment_size); +} + +static ssize_t ncm_opts_max_segment_size_store(struct config_item *item, + const char *page, size_t len) +{ + struct f_ncm_opts *opts = to_f_ncm_opts(item); + u16 segment_size; + int ret; + + mutex_lock(&opts->lock); + if (opts->refcnt) { + ret = -EBUSY; + goto out; + } + + ret = kstrtou16(page, 0, &segment_size); + if (ret) + goto out; + + if (segment_size > MAX_DATAGRAM_SIZE) { + ret = -EINVAL; + goto out; + } + + opts->max_segment_size = segment_size; + ret = len; +out: + mutex_unlock(&opts->lock); + return ret; +} + +CONFIGFS_ATTR(ncm_opts_, max_segment_size); + static struct configfs_attribute *ncm_attrs[] = { &ncm_opts_attr_dev_addr, &ncm_opts_attr_host_addr, &ncm_opts_attr_qmult, &ncm_opts_attr_ifname, + &ncm_opts_attr_max_segment_size, NULL, }; @@ -1623,6 +1685,7 @@ static struct usb_function_instance *ncm_alloc_inst(void) kfree(opts); return ERR_CAST(net); } + opts->max_segment_size = cpu_to_le16(ETH_FRAME_LEN); INIT_LIST_HEAD(&opts->ncm_os_desc.ext_prop); descs[0] = &opts->ncm_os_desc; diff --git a/drivers/usb/gadget/function/u_ncm.h b/drivers/usb/gadget/function/u_ncm.h index 5408854d8407..49ec095cdb4b 100644 --- a/drivers/usb/gadget/function/u_ncm.h +++ b/drivers/usb/gadget/function/u_ncm.h @@ -31,6 +31,8 @@ struct f_ncm_opts { */ struct mutex lock; int refcnt; + + u16 max_segment_size; }; #endif /* U_NCM_H */ |