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Diffstat (limited to 'Documentation/networking/stmmac.txt')
| -rw-r--r-- | Documentation/networking/stmmac.txt | 44 |
1 files changed, 42 insertions, 2 deletions
diff --git a/Documentation/networking/stmmac.txt b/Documentation/networking/stmmac.txt index 57a24108b845..8d67980fabe8 100644 --- a/Documentation/networking/stmmac.txt +++ b/Documentation/networking/stmmac.txt @@ -76,7 +76,16 @@ core. 4.5) DMA descriptors Driver handles both normal and enhanced descriptors. The latter has been only -tested on DWC Ether MAC 10/100/1000 Universal version 3.41a. +tested on DWC Ether MAC 10/100/1000 Universal version 3.41a and later. + +STMMAC supports DMA descriptor to operate both in dual buffer (RING) +and linked-list(CHAINED) mode. In RING each descriptor points to two +data buffer pointers whereas in CHAINED mode they point to only one data +buffer pointer. RING mode is the default. + +In CHAINED mode each descriptor will have pointer to next descriptor in +the list, hence creating the explicit chaining in the descriptor itself, +whereas such explicit chaining is not possible in RING mode. 4.6) Ethtool support Ethtool is supported. Driver statistics and internal errors can be taken using: @@ -235,7 +244,38 @@ reset procedure etc). o enh_desc.c: functions for handling enhanced descriptors o norm_desc.c: functions for handling normal descriptors -5) TODO: +5) Debug Information + +The driver exports many information i.e. internal statistics, +debug information, MAC and DMA registers etc. + +These can be read in several ways depending on the +type of the information actually needed. + +For example a user can be use the ethtool support +to get statistics: e.g. using: ethtool -S ethX +(that shows the Management counters (MMC) if supported) +or sees the MAC/DMA registers: e.g. using: ethtool -d ethX + +Compiling the Kernel with CONFIG_DEBUG_FS and enabling the +STMMAC_DEBUG_FS option the driver will export the following +debugfs entries: + +/sys/kernel/debug/stmmaceth/descriptors_status + To show the DMA TX/RX descriptor rings + +Developer can also use the "debug" module parameter to get +further debug information. + +In the end, there are other macros (that cannot be enabled +via menuconfig) to turn-on the RX/TX DMA debugging, +specific MAC core debug printk etc. Others to enable the +debug in the TX and RX processes. +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: o XGMAC is not supported. o Review the timer optimisation code to use an embedded device that will be available in new chip generations. |