stmmac: update the driver Documentation and add EEE

This patch updates the stmmac's documentation adding
some missing files in the section used to describe the
internal driver's structure.

Also the patch adds a new section to describe the EEE support.
Signed-off-by: NGiuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Documentation/networking/stmmac.txt

@@ -257,9 +257,11 @@ reset procedure etc).
  o Makefile
  o stmmac_main.c: main network device driver;
  o stmmac_mdio.c: mdio functions;
+ o stmmac_pci: PCI driver;
+ o stmmac_platform.c: platform driver
  o stmmac_ethtool.c: ethtool support;
  o stmmac_timer.[ch]: timer code used for mitigating the driver dma interrupts
-		      Only tested on ST40 platforms based.
+		      (only tested on ST40 platforms based);
  o stmmac.h: private driver structure;
  o common.h: common definitions and VFTs;
  o descs.h: descriptor structure definitions;
@@ -269,9 +271,11 @@ reset procedure etc).
  o dwmac100_core: MAC 100 core and dma code;
  o dwmac100_dma.c: dma funtions for the MAC chip;
  o dwmac1000.h: specific header file for the MAC;
- o dwmac_lib.c: generic DMA functions shared among chips
- o enh_desc.c: functions for handling enhanced descriptors
- o norm_desc.c: functions for handling normal descriptors
+ o dwmac_lib.c: generic DMA functions shared among chips;
+ 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;
 
 5) Debug Information
 
@@ -304,7 +308,27 @@ All these are only useful during the developing stage
 and should never enabled inside the code for general usage.
 In fact, these can generate an huge amount of debug messages.
 
-6) TODO:
+6) Energy Efficient Ethernet
+
+Energy Efficient Ethernet(EEE) enables IEEE 802.3 MAC sublayer along
+with a family of Physical layer to operate in the Low power Idle(LPI)
+mode. The EEE mode supports the IEEE 802.3 MAC operation at 100Mbps,
+1000Mbps & 10Gbps.
+
+The LPI mode allows power saving by switching off parts of the
+communication device functionality when there is no data to be
+transmitted & received. The system on both the side of the link can
+disable some functionalities & save power during the period of low-link
+utilization. The MAC controls whether the system should enter or exit
+the LPI mode & communicate this to PHY.
+
+As soon as the interface is opened, the driver verifies if the EEE can
+be supported. This is done by looking at both the DMA HW capability
+register and the PHY devices MCD registers.
+To enter in Tx LPI mode the driver needs to have a software timer
+that enable and disable the LPI mode when there is nothing to be
+transmitted.
+
+7) TODO:
  o XGMAC is not supported.
- o Add the EEE - Energy Efficient Ethernet
  o Add the PTP - precision time protocol