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Diffstat (limited to 'Documentation/ABI/testing/sysfs-class-net-cdc_ncm')
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diff --git a/Documentation/ABI/testing/sysfs-class-net-cdc_ncm b/Documentation/ABI/testing/sysfs-class-net-cdc_ncm new file mode 100644 index 0000000000..06416d0e16 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-net-cdc_ncm @@ -0,0 +1,168 @@ +What: /sys/class/net/<iface>/cdc_ncm/min_tx_pkt +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork <bjorn@mork.no> +Description: + The driver will pad NCM Transfer Blocks (NTBs) longer + than this to tx_max, allowing the device to receive + tx_max sized frames with no terminating short + packet. NTBs shorter than this limit are transmitted + as-is, without any padding, and are terminated with a + short USB packet. + + Padding to tx_max allows the driver to transmit NTBs + back-to-back without any interleaving short USB + packets. This reduces the number of short packet + interrupts in the device, and represents a tradeoff + between USB bus bandwidth and device DMA optimization. + + Set to 0 to pad all frames. Set greater than tx_max to + disable all padding. + +What: /sys/class/net/<iface>/cdc_ncm/ndp_to_end +Date: Dec 2015 +KernelVersion: 4.5 +Contact: Bjørn Mork <bjorn@mork.no> +Description: + Boolean attribute showing the status of the "NDP to + end" quirk. Defaults to 'N', except for devices + already known to need it enabled. + + The "NDP to end" quirk makes the driver place the NDP + (the packet index table) after the payload. The NCM + specification does not mandate this, but some devices + are known to be more restrictive. Write 'Y' to this + attribute for temporary testing of a suspect device + failing to work with the default driver settings. + + A device entry should be added to the driver if this + quirk is found to be required. + +What: /sys/class/net/<iface>/cdc_ncm/rx_max +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork <bjorn@mork.no> +Description: + The maximum NTB size for RX. Cannot exceed the + maximum value supported by the device. Must allow at + least one max sized datagram plus headers. + + The actual limits are device dependent. See + dwNtbInMaxSize. + + Note: Some devices will silently ignore changes to + this value, resulting in oversized NTBs and + corresponding framing errors. + +What: /sys/class/net/<iface>/cdc_ncm/tx_max +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork <bjorn@mork.no> +Description: + The maximum NTB size for TX. Cannot exceed the + maximum value supported by the device. Must allow at + least one max sized datagram plus headers. + + The actual limits are device dependent. See + dwNtbOutMaxSize. + +What: /sys/class/net/<iface>/cdc_ncm/tx_timer_usecs +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork <bjorn@mork.no> +Description: + Datagram aggregation timeout in µs. The driver will + wait up to 3 times this timeout for more datagrams to + aggregate before transmitting an NTB frame. + + Valid range: 5 to 4000000 + + Set to 0 to disable aggregation. + +The following read-only attributes all represent fields of the +structure defined in section 6.2.1 "GetNtbParameters" of "Universal +Serial Bus Communications Class Subclass Specifications for Network +Control Model Devices" (CDC NCM), Revision 1.0 (Errata 1), November +24, 2010 from USB Implementers Forum, Inc. The descriptions are +quoted from table 6-3 of CDC NCM: "NTB Parameter Structure". + +What: /sys/class/net/<iface>/cdc_ncm/bmNtbFormatsSupported +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork <bjorn@mork.no> +Description: + - Bit 0: 16-bit NTB supported (set to 1) + - Bit 1: 32-bit NTB supported + - Bits 2 – 15: reserved (reset to zero; must be ignored by host) + +What: /sys/class/net/<iface>/cdc_ncm/dwNtbInMaxSize +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork <bjorn@mork.no> +Description: + IN NTB Maximum Size in bytes + +What: /sys/class/net/<iface>/cdc_ncm/wNdpInDivisor +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork <bjorn@mork.no> +Description: + Divisor used for IN NTB Datagram payload alignment + +What: /sys/class/net/<iface>/cdc_ncm/wNdpInPayloadRemainder +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork <bjorn@mork.no> +Description: + Remainder used to align input datagram payload within + the NTB: (Payload Offset) mod (wNdpInDivisor) = + wNdpInPayloadRemainder + +What: /sys/class/net/<iface>/cdc_ncm/wNdpInAlignment +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork <bjorn@mork.no> +Description: + NDP alignment modulus for NTBs on the IN pipe. Shall + be a power of 2, and shall be at least 4. + +What: /sys/class/net/<iface>/cdc_ncm/dwNtbOutMaxSize +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork <bjorn@mork.no> +Description: + OUT NTB Maximum Size + +What: /sys/class/net/<iface>/cdc_ncm/wNdpOutDivisor +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork <bjorn@mork.no> +Description: + OUT NTB Datagram alignment modulus + +What: /sys/class/net/<iface>/cdc_ncm/wNdpOutPayloadRemainder +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork <bjorn@mork.no> +Description: + Remainder used to align output datagram payload + offsets within the NTB: Padding, shall be transmitted + as zero by function, and ignored by host. (Payload + Offset) mod (wNdpOutDivisor) = wNdpOutPayloadRemainder + +What: /sys/class/net/<iface>/cdc_ncm/wNdpOutAlignment +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork <bjorn@mork.no> +Description: + NDP alignment modulus for use in NTBs on the OUT + pipe. Shall be a power of 2, and shall be at least 4. + +What: /sys/class/net/<iface>/cdc_ncm/wNtbOutMaxDatagrams +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork <bjorn@mork.no> +Description: + Maximum number of datagrams that the host may pack + into a single OUT NTB. Zero means that the device + imposes no limit. |