From: Bjørn Mork Date: Fri, 30 May 2014 07:31:10 +0000 (+0200) Subject: net: cdc_ncm: document the sysfs API X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=e3cfeefc0e491af00155525131285821e26f7715;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git net: cdc_ncm: document the sysfs API Adding documentation for all the driver specific sysfs attributes. Cc: Peter Stuge Signed-off-by: Bjørn Mork Signed-off-by: David S. Miller --- 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 000000000000..5cedf72df358 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-net-cdc_ncm @@ -0,0 +1,149 @@ +What: /sys/class/net//cdc_ncm/min_tx_pkt +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork +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//cdc_ncm/rx_max +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork +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//cdc_ncm/tx_max +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork +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//cdc_ncm/tx_timer_usecs +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork +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//cdc_ncm/bmNtbFormatsSupported +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork +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//cdc_ncm/dwNtbInMaxSize +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork +Description: + IN NTB Maximum Size in bytes + +What: /sys/class/net//cdc_ncm/wNdpInDivisor +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork +Description: + Divisor used for IN NTB Datagram payload alignment + +What: /sys/class/net//cdc_ncm/wNdpInPayloadRemainder +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork +Description: + Remainder used to align input datagram payload within + the NTB: (Payload Offset) mod (wNdpInDivisor) = + wNdpInPayloadRemainder + +What: /sys/class/net//cdc_ncm/wNdpInAlignment +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork +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//cdc_ncm/dwNtbOutMaxSize +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork +Description: + OUT NTB Maximum Size + +What: /sys/class/net//cdc_ncm/wNdpOutDivisor +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork +Description: + OUT NTB Datagram alignment modulus + +What: /sys/class/net//cdc_ncm/wNdpOutPayloadRemainder +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork +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//cdc_ncm/wNdpOutAlignment +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork +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//cdc_ncm/wNtbOutMaxDatagrams +Date: May 2014 +KernelVersion: 3.16 +Contact: Bjørn Mork +Description: + Maximum number of datagrams that the host may pack + into a single OUT NTB. Zero means that the device + imposes no limit.