From 0b7a43d37633614113ac54af73c193862dff4e50 Mon Sep 17 00:00:00 2001 From: Alexandre TORGUE Date: Fri, 1 Apr 2016 11:37:35 +0200 Subject: [PATCH] Documentation: networking: update stmmac Update stmmac driver documentation according to new GMAC 4.x family. Signed-off-by: Alexandre TORGUE Signed-off-by: David S. Miller --- Documentation/networking/stmmac.txt | 44 ++++++++++++++++++++++++++++++++----- 1 file changed, 38 insertions(+), 6 deletions(-) diff --git a/Documentation/networking/stmmac.txt b/Documentation/networking/stmmac.txt index d64a147..671fe3d 100644 --- a/Documentation/networking/stmmac.txt +++ b/Documentation/networking/stmmac.txt @@ -1,6 +1,6 @@ STMicroelectronics 10/100/1000 Synopsys Ethernet driver -Copyright (C) 2007-2014 STMicroelectronics Ltd +Copyright (C) 2007-2015 STMicroelectronics Ltd Author: Giuseppe Cavallaro This is the driver for the MAC 10/100/1000 on-chip Ethernet controllers @@ -138,6 +138,8 @@ struct plat_stmmacenet_data { int (*init)(struct platform_device *pdev, void *priv); void (*exit)(struct platform_device *pdev, void *priv); void *bsp_priv; + int has_gmac4; + bool tso_en; }; Where: @@ -181,6 +183,8 @@ Where: registers. init/exit callbacks should not use or modify platform data. o bsp_priv: another private pointer. + o has_gmac4: uses GMAC4 core. + o tso_en: Enables TSO (TCP Segmentation Offload) feature. For MDIO bus The we have: @@ -278,6 +282,13 @@ Please see the following document: o stmmac_ethtool.c: to implement the ethtool support; o stmmac.h: private driver structure; o common.h: common definitions and VFTs; + o mmc_core.c/mmc.h: Management MAC Counters; + o stmmac_hwtstamp.c: HW timestamp support for PTP; + o stmmac_ptp.c: PTP 1588 clock; + o dwmac-.c: these are for the platform glue-logic file; e.g. dwmac-sti.c + for STMicroelectronics SoCs. + +- GMAC 3.x o descs.h: descriptor structure definitions; o dwmac1000_core.c: dwmac GiGa core functions; o dwmac1000_dma.c: dma functions for the GMAC chip; @@ -289,11 +300,32 @@ Please see the following document: o enh_desc.c: functions for handling enhanced descriptors; o norm_desc.c: functions for handling normal descriptors; o chain_mode.c/ring_mode.c:: functions to manage RING/CHAINED modes; - o mmc_core.c/mmc.h: Management MAC Counters; - o stmmac_hwtstamp.c: HW timestamp support for PTP; - o stmmac_ptp.c: PTP 1588 clock; - o dwmac-.c: these are for the platform glue-logic file; e.g. dwmac-sti.c - for STMicroelectronics SoCs. + +- GMAC4.x generation + o dwmac4_core.c: dwmac GMAC4.x core functions; + o dwmac4_desc.c: functions for handling GMAC4.x descriptors; + o dwmac4_descs.h: descriptor definitions; + o dwmac4_dma.c: dma functions for the GMAC4.x chip; + o dwmac4_dma.h: dma definitions for the GMAC4.x chip; + o dwmac4.h: core definitions for the GMAC4.x chip; + o dwmac4_lib.c: generic GMAC4.x functions; + +4.12) TSO support (GMAC4.x) + +TSO (Tcp Segmentation Offload) feature is supported by GMAC 4.x chip family. +When a packet is sent through TCP protocol, the TCP stack ensures that +the SKB provided to the low level driver (stmmac in our case) matches with +the maximum frame len (IP header + TCP header + payload <= 1500 bytes (for +MTU set to 1500)). It means that if an application using TCP want to send a +packet which will have a length (after adding headers) > 1514 the packet +will be split in several TCP packets: The data payload is split and headers +(TCP/IP ..) are added. It is done by software. + +When TSO is enabled, the TCP stack doesn't care about the maximum frame +length and provide SKB packet to stmmac as it is. The GMAC IP will have to +perform the segmentation by it self to match with maximum frame length. + +This feature can be enabled in device tree through "snps,tso" entry. 5) Debug Information -- 2.7.4