| Commit message (Collapse) | Author | Age | Files | Lines | |
|---|---|---|---|---|---|
| * | stmmac: fix PTP support for GMAC4 | Giuseppe CAVALLARO | 2016-11-15 | 1 | -0/+4 |
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Due to bad management of the descriptors, when use ptp4l, kernel panics as shown below: ----------------------------------------------------------- Unable to handle kernel NULL pointer dereference at virtual address 000001ac ... Internal error: Oops: 17 [#1] SMP ARM ... Hardware name: STi SoC with Flattened Device Tree task: c0c05e80 task.stack: c0c00000 PC is at dwmac4_wrback_get_tx_timestamp_status+0x0/0xc LR is at stmmac_tx_clean+0x2f8/0x4d4 ----------------------------------------------------------- In case of GMAC4 the extended descriptor pointers were used for getting the timestamp. These are NULL for this HW, and the normal ones must be used. The PTP also had problems on this chip due to the bad register management and issues on the algo adopted to setup the PTP and getting the timestamp values from the descriptors. Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com> Acked-by: Rayagond Kokatanur <rayagond@vayavyalabs.com> Acked-by: Alexandre TORGUE <alexandre.torgue@st.com> Acked-by: Richard Cochran <richardcochran@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> | ||||
| * | stmmac: add descriptors function for GMAC 4.xx | Alexandre TORGUE | 2016-04-02 | 1 | -0/+129 |
| One of main changes of GMAC 4.xx IP is descriptors management. -descriptors are only used in ring mode. -A descriptor is composed of 4 32bits registers (no more extended descriptors) -descriptor mechanism (Tx for example, but it is exactly the same for RX): -useful registers: -DMA_CH#_TxDesc_Ring_Len: length of transmit descriptor ring -DMA_CH#_TxDesc_List_Address: start address of the ring -DMA_CH#_TxDesc_Tail_Pointer: address of the last descriptor to send + 1. -DMA_CH#_TxDesc_Current_App_TxDesc: address of the current descriptor -The descriptor Tail Pointer register contains the pointer to the descriptor address (N). The base address and the current descriptor decide the address of the current descriptor that the DMA can process. The descriptors up to one location less than the one indicated by the descriptor tail pointer (N-1) are owned by the DMA. The DMA continues to process the descriptors until the following condition occurs: "current descriptor pointer == Descriptor Tail pointer" Then the DMA goes into suspend mode. The application must perform a write to descriptor tail pointer register and update the tail pointer to have the following condition and to start a new transfer: "current descriptor pointer < Descriptor tail pointer" The DMA automatically wraps around the base address when the end of ring is reached. -New features are available on IP: -TSO (TCP Segmentation Offload) for TX only -Split header: to have header and payload in 2 different buffers Signed-off-by: Alexandre TORGUE <alexandre.torgue@st.com> Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com> Signed-off-by: David S. Miller <davem@davemloft.net> | |||||
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