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diff --git a/Documentation/networking/device_drivers/stmicro/stmmac.rst b/Documentation/networking/device_drivers/stmicro/stmmac.rst new file mode 100644 index 000000000000..c34bab3d2df0 --- /dev/null +++ b/Documentation/networking/device_drivers/stmicro/stmmac.rst @@ -0,0 +1,697 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +============================================================== +Linux Driver for the Synopsys(R) Ethernet Controllers "stmmac" +============================================================== + +Authors: Giuseppe Cavallaro <peppe.cavallaro@st.com>, +Alexandre Torgue <alexandre.torgue@st.com>, Jose Abreu <joabreu@synopsys.com> + +Contents +======== + +- In This Release +- Feature List +- Kernel Configuration +- Command Line Parameters +- Driver Information and Notes +- Debug Information +- Support + +In This Release +=============== + +This file describes the stmmac Linux Driver for all the Synopsys(R) Ethernet +Controllers. + +Currently, this network device driver is for all STi embedded MAC/GMAC +(i.e. 7xxx/5xxx SoCs), SPEAr (arm), Loongson1B (mips) and XILINX XC2V3000 +FF1152AMT0221 D1215994A VIRTEX FPGA board. The Synopsys Ethernet QoS 5.0 IPK +is also supported. + +DesignWare(R) Cores Ethernet MAC 10/100/1000 Universal version 3.70a +(and older) and DesignWare(R) Cores Ethernet Quality-of-Service version 4.0 +(and upper) have been used for developing this driver as well as +DesignWare(R) Cores XGMAC - 10G Ethernet MAC. + +This driver supports both the platform bus and PCI. + +This driver includes support for the following Synopsys(R) DesignWare(R) +Cores Ethernet Controllers and corresponding minimum and maximum versions: + ++-------------------------------+--------------+--------------+--------------+ +| Controller Name | Min. Version | Max. Version | Abbrev. Name | ++===============================+==============+==============+==============+ +| Ethernet MAC Universal | N/A | 3.73a | GMAC | ++-------------------------------+--------------+--------------+--------------+ +| Ethernet Quality-of-Service | 4.00a | N/A | GMAC4+ | ++-------------------------------+--------------+--------------+--------------+ +| XGMAC - 10G Ethernet MAC | 2.10a | N/A | XGMAC2+ | ++-------------------------------+--------------+--------------+--------------+ + +For questions related to hardware requirements, refer to the documentation +supplied with your Ethernet adapter. All hardware requirements listed apply +to use with Linux. + +Feature List +============ + +The following features are available in this driver: + - GMII/MII/RGMII/SGMII/RMII/XGMII Interface + - Half-Duplex / Full-Duplex Operation + - Energy Efficient Ethernet (EEE) + - IEEE 802.3x PAUSE Packets (Flow Control) + - RMON/MIB Counters + - IEEE 1588 Timestamping (PTP) + - Pulse-Per-Second Output (PPS) + - MDIO Clause 22 / Clause 45 Interface + - MAC Loopback + - ARP Offloading + - Automatic CRC / PAD Insertion and Checking + - Checksum Offload for Received and Transmitted Packets + - Standard or Jumbo Ethernet Packets + - Source Address Insertion / Replacement + - VLAN TAG Insertion / Replacement / Deletion / Filtering (HASH and PERFECT) + - Programmable TX and RX Watchdog and Coalesce Settings + - Destination Address Filtering (PERFECT) + - HASH Filtering (Multicast) + - Layer 3 / Layer 4 Filtering + - Remote Wake-Up Detection + - Receive Side Scaling (RSS) + - Frame Preemption for TX and RX + - Programmable Burst Length, Threshold, Queue Size + - Multiple Queues (up to 8) + - Multiple Scheduling Algorithms (TX: WRR, DWRR, WFQ, SP, CBS, EST, TBS; + RX: WRR, SP) + - Flexible RX Parser + - TCP / UDP Segmentation Offload (TSO, USO) + - Split Header (SPH) + - Safety Features (ECC Protection, Data Parity Protection) + - Selftests using Ethtool + +Kernel Configuration +==================== + +The kernel configuration option is ``CONFIG_STMMAC_ETH``: + - ``CONFIG_STMMAC_PLATFORM``: is to enable the platform driver. + - ``CONFIG_STMMAC_PCI``: is to enable the pci driver. + +Command Line Parameters +======================= + +If the driver is built as a module the following optional parameters are used +by entering them on the command line with the modprobe command using this +syntax (e.g. for PCI module):: + + modprobe stmmac_pci [<option>=<VAL1>,<VAL2>,...] + +Driver parameters can be also passed in command line by using:: + + stmmaceth=watchdog:100,chain_mode=1 + +The default value for each parameter is generally the recommended setting, +unless otherwise noted. + +watchdog +-------- +:Valid Range: 5000-None +:Default Value: 5000 + +This parameter overrides the transmit timeout in milliseconds. + +debug +----- +:Valid Range: 0-16 (0=none,...,16=all) +:Default Value: 0 + +This parameter adjusts the level of debug messages displayed in the system +logs. + +phyaddr +------- +:Valid Range: 0-31 +:Default Value: -1 + +This parameter overrides the physical address of the PHY device. + +flow_ctrl +--------- +:Valid Range: 0-3 (0=off,1=rx,2=tx,3=rx/tx) +:Default Value: 3 + +This parameter changes the default Flow Control ability. + +pause +----- +:Valid Range: 0-65535 +:Default Value: 65535 + +This parameter changes the default Flow Control Pause time. + +tc +-- +:Valid Range: 64-256 +:Default Value: 64 + +This parameter changes the default HW FIFO Threshold control value. + +buf_sz +------ +:Valid Range: 1536-16384 +:Default Value: 1536 + +This parameter changes the default RX DMA packet buffer size. + +eee_timer +--------- +:Valid Range: 0-None +:Default Value: 1000 + +This parameter changes the default LPI TX Expiration time in milliseconds. + +chain_mode +---------- +:Valid Range: 0-1 (0=off,1=on) +:Default Value: 0 + +This parameter changes the default mode of operation from Ring Mode to +Chain Mode. + +Driver Information and Notes +============================ + +Transmit Process +---------------- + +The xmit method is invoked when the kernel needs to transmit a packet; it sets +the descriptors in the ring and informs the DMA engine that there is a packet +ready to be transmitted. + +By default, the driver sets the ``NETIF_F_SG`` bit in the features field of +the ``net_device`` structure, enabling the scatter-gather feature. This is +true on chips and configurations where the checksum can be done in hardware. + +Once the controller has finished transmitting the packet, timer will be +scheduled to release the transmit resources. + +Receive Process +--------------- + +When one or more packets are received, an interrupt happens. The interrupts +are not queued, so the driver has to scan all the descriptors in the ring +during the receive process. + +This is based on NAPI, so the interrupt handler signals only if there is work +to be done, and it exits. Then the poll method will be scheduled at some +future point. + +The incoming packets are stored, by the DMA, in a list of pre-allocated socket +buffers in order to avoid the memcpy (zero-copy). + +Interrupt Mitigation +-------------------- + +The driver is able to mitigate the number of its DMA interrupts using NAPI for +the reception on chips older than the 3.50. New chips have an HW RX Watchdog +used for this mitigation. + +Mitigation parameters can be tuned by ethtool. + +WoL +--- + +Wake up on Lan feature through Magic and Unicast frames are supported for the +GMAC, GMAC4/5 and XGMAC core. + +DMA Descriptors +--------------- + +Driver handles both normal and alternate descriptors. The latter has been only +tested on DesignWare(R) Cores Ethernet MAC 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. + +Extended Descriptors +-------------------- + +The extended descriptors give us information about the Ethernet payload when +it is carrying PTP packets or TCP/UDP/ICMP over IP. These are not available on +GMAC Synopsys(R) chips older than the 3.50. At probe time the driver will +decide if these can be actually used. This support also is mandatory for PTPv2 +because the extra descriptors are used for saving the hardware timestamps and +Extended Status. + +Ethtool Support +--------------- + +Ethtool is supported. For example, driver statistics (including RMON), +internal errors can be taken using:: + + ethtool -S ethX + +Ethtool selftests are also supported. This allows to do some early sanity +checks to the HW using MAC and PHY loopback mechanisms:: + + ethtool -t ethX + +Jumbo and Segmentation Offloading +--------------------------------- + +Jumbo frames are supported and tested for the GMAC. The GSO has been also +added but it's performed in software. LRO is not supported. + +TSO Support +----------- + +TSO (TCP Segmentation Offload) feature is supported by GMAC > 4.x and XGMAC +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. + +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 and 1Gbps. + +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 and +save power during the period of low-link utilization. The MAC controls whether +the system should enter or exit the LPI mode and 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. + +Precision Time Protocol (PTP) +----------------------------- + +The driver supports the IEEE 1588-2002, Precision Time Protocol (PTP), which +enables precise synchronization of clocks in measurement and control systems +implemented with technologies such as network communication. + +In addition to the basic timestamp features mentioned in IEEE 1588-2002 +Timestamps, new GMAC cores support the advanced timestamp features. +IEEE 1588-2008 can be enabled when configuring the Kernel. + +SGMII/RGMII Support +------------------- + +New GMAC devices provide own way to manage RGMII/SGMII. This information is +available at run-time by looking at the HW capability register. This means +that the stmmac can manage auto-negotiation and link status w/o using the +PHYLIB stuff. In fact, the HW provides a subset of extended registers to +restart the ANE, verify Full/Half duplex mode and Speed. Thanks to these +registers, it is possible to look at the Auto-negotiated Link Parter Ability. + +Physical +-------- + +The driver is compatible with Physical Abstraction Layer to be connected with +PHY and GPHY devices. + +Platform Information +-------------------- + +Several information can be passed through the platform and device-tree. + +:: + + struct plat_stmmacenet_data { + +1) Bus identifier:: + + int bus_id; + +2) PHY Physical Address. If set to -1 the driver will pick the first PHY it +finds:: + + int phy_addr; + +3) PHY Device Interface:: + + int interface; + +4) Specific platform fields for the MDIO bus:: + + struct stmmac_mdio_bus_data *mdio_bus_data; + +5) Internal DMA parameters:: + + struct stmmac_dma_cfg *dma_cfg; + +6) Fixed CSR Clock Range selection:: + + int clk_csr; + +7) HW uses the GMAC core:: + + int has_gmac; + +8) If set the MAC will use Enhanced Descriptors:: + + int enh_desc; + +9) Core is able to perform TX Checksum and/or RX Checksum in HW:: + + int tx_coe; + int rx_coe; + +11) Some HWs are not able to perform the csum in HW for over-sized frames due +to limited buffer sizes. Setting this flag the csum will be done in SW on +JUMBO frames:: + + int bugged_jumbo; + +12) Core has the embedded power module:: + + int pmt; + +13) Force DMA to use the Store and Forward mode or Threshold mode:: + + int force_sf_dma_mode; + int force_thresh_dma_mode; + +15) Force to disable the RX Watchdog feature and switch to NAPI mode:: + + int riwt_off; + +16) Limit the maximum operating speed and MTU:: + + int max_speed; + int maxmtu; + +18) Number of Multicast/Unicast filters:: + + int multicast_filter_bins; + int unicast_filter_entries; + +20) Limit the maximum TX and RX FIFO size:: + + int tx_fifo_size; + int rx_fifo_size; + +21) Use the specified number of TX and RX Queues:: + + u32 rx_queues_to_use; + u32 tx_queues_to_use; + +22) Use the specified TX and RX scheduling algorithm:: + + u8 rx_sched_algorithm; + u8 tx_sched_algorithm; + +23) Internal TX and RX Queue parameters:: + + struct stmmac_rxq_cfg rx_queues_cfg[MTL_MAX_RX_QUEUES]; + struct stmmac_txq_cfg tx_queues_cfg[MTL_MAX_TX_QUEUES]; + +24) This callback is used for modifying some syscfg registers (on ST SoCs) +according to the link speed negotiated by the physical layer:: + + void (*fix_mac_speed)(void *priv, unsigned int speed); + +25) Callbacks used for calling a custom initialization; This is sometimes +necessary on some platforms (e.g. ST boxes) where the HW needs to have set +some PIO lines or system cfg registers. init/exit callbacks should not use +or modify platform data:: + + int (*init)(struct platform_device *pdev, void *priv); + void (*exit)(struct platform_device *pdev, void *priv); + +26) Perform HW setup of the bus. For example, on some ST platforms this field +is used to configure the AMBA bridge to generate more efficient STBus traffic:: + + struct mac_device_info *(*setup)(void *priv); + void *bsp_priv; + +27) Internal clocks and rates:: + + struct clk *stmmac_clk; + struct clk *pclk; + struct clk *clk_ptp_ref; + unsigned int clk_ptp_rate; + unsigned int clk_ref_rate; + s32 ptp_max_adj; + +28) Main reset:: + + struct reset_control *stmmac_rst; + +29) AXI Internal Parameters:: + + struct stmmac_axi *axi; + +30) HW uses GMAC>4 cores:: + + int has_gmac4; + +31) HW is sun8i based:: + + bool has_sun8i; + +32) Enables TSO feature:: + + bool tso_en; + +33) Enables Receive Side Scaling (RSS) feature:: + + int rss_en; + +34) MAC Port selection:: + + int mac_port_sel_speed; + +35) Enables TX LPI Clock Gating:: + + bool en_tx_lpi_clockgating; + +36) HW uses XGMAC>2.10 cores:: + + int has_xgmac; + +:: + + } + +For MDIO bus data, we have: + +:: + + struct stmmac_mdio_bus_data { + +1) PHY mask passed when MDIO bus is registered:: + + unsigned int phy_mask; + +2) List of IRQs, one per PHY:: + + int *irqs; + +3) If IRQs is NULL, use this for probed PHY:: + + int probed_phy_irq; + +4) Set to true if PHY needs reset:: + + bool needs_reset; + +:: + + } + +For DMA engine configuration, we have: + +:: + + struct stmmac_dma_cfg { + +1) Programmable Burst Length (TX and RX):: + + int pbl; + +2) If set, DMA TX / RX will use this value rather than pbl:: + + int txpbl; + int rxpbl; + +3) Enable 8xPBL:: + + bool pblx8; + +4) Enable Fixed or Mixed burst:: + + int fixed_burst; + int mixed_burst; + +5) Enable Address Aligned Beats:: + + bool aal; + +6) Enable Enhanced Addressing (> 32 bits):: + + bool eame; + +:: + + } + +For DMA AXI parameters, we have: + +:: + + struct stmmac_axi { + +1) Enable AXI LPI:: + + bool axi_lpi_en; + bool axi_xit_frm; + +2) Set AXI Write / Read maximum outstanding requests:: + + u32 axi_wr_osr_lmt; + u32 axi_rd_osr_lmt; + +3) Set AXI 4KB bursts:: + + bool axi_kbbe; + +4) Set AXI maximum burst length map:: + + u32 axi_blen[AXI_BLEN]; + +5) Set AXI Fixed burst / mixed burst:: + + bool axi_fb; + bool axi_mb; + +6) Set AXI rebuild incrx mode:: + + bool axi_rb; + +:: + + } + +For the RX Queues configuration, we have: + +:: + + struct stmmac_rxq_cfg { + +1) Mode to use (DCB or AVB):: + + u8 mode_to_use; + +2) DMA channel to use:: + + u32 chan; + +3) Packet routing, if applicable:: + + u8 pkt_route; + +4) Use priority routing, and priority to route:: + + bool use_prio; + u32 prio; + +:: + + } + +For the TX Queues configuration, we have: + +:: + + struct stmmac_txq_cfg { + +1) Queue weight in scheduler:: + + u32 weight; + +2) Mode to use (DCB or AVB):: + + u8 mode_to_use; + +3) Credit Base Shaper Parameters:: + + u32 send_slope; + u32 idle_slope; + u32 high_credit; + u32 low_credit; + +4) Use priority scheduling, and priority:: + + bool use_prio; + u32 prio; + +:: + + } + +Device Tree Information +----------------------- + +Please refer to the following document: +Documentation/devicetree/bindings/net/snps,dwmac.yaml + +HW Capabilities +--------------- + +Note that, starting from new chips, where it is available the HW capability +register, many configurations are discovered at run-time for example to +understand if EEE, HW csum, PTP, enhanced descriptor etc are actually +available. As strategy adopted in this driver, the information from the HW +capability register can replace what has been passed from the platform. + +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`` the driver will export the +following debugfs entries: + + - ``descriptors_status``: To show the DMA TX/RX descriptor rings + - ``dma_cap``: To show the HW Capabilities + +Developer can also use the ``debug`` module parameter to get further debug +information (please see: NETIF Msg Level). + +Support +======= + +If an issue is identified with the released source code on a supported kernel +with a supported adapter, email the specific information related to the +issue to netdev@vger.kernel.org diff --git a/Documentation/networking/device_drivers/stmicro/stmmac.txt b/Documentation/networking/device_drivers/stmicro/stmmac.txt deleted file mode 100644 index 1ae979fd90d2..000000000000 --- a/Documentation/networking/device_drivers/stmicro/stmmac.txt +++ /dev/null @@ -1,401 +0,0 @@ - STMicroelectronics 10/100/1000 Synopsys Ethernet driver - -Copyright (C) 2007-2015 STMicroelectronics Ltd -Author: Giuseppe Cavallaro <peppe.cavallaro@st.com> - -This is the driver for the MAC 10/100/1000 on-chip Ethernet controllers -(Synopsys IP blocks). - -Currently this network device driver is for all STi embedded MAC/GMAC -(i.e. 7xxx/5xxx SoCs), SPEAr (arm), Loongson1B (mips) and XLINX XC2V3000 -FF1152AMT0221 D1215994A VIRTEX FPGA board. - -DWC Ether MAC 10/100/1000 Universal version 3.70a (and older) and DWC Ether -MAC 10/100 Universal version 4.0 have been used for developing this driver. - -This driver supports both the platform bus and PCI. - -Please, for more information also visit: www.stlinux.com - -1) Kernel Configuration -The kernel configuration option is STMMAC_ETH: - Device Drivers ---> Network device support ---> Ethernet (1000 Mbit) ---> - STMicroelectronics 10/100/1000 Ethernet driver (STMMAC_ETH) - -CONFIG_STMMAC_PLATFORM: is to enable the platform driver. -CONFIG_STMMAC_PCI: is to enable the pci driver. - -2) Driver parameters list: - debug: message level (0: no output, 16: all); - phyaddr: to manually provide the physical address to the PHY device; - buf_sz: DMA buffer size; - tc: control the HW FIFO threshold; - watchdog: transmit timeout (in milliseconds); - flow_ctrl: Flow control ability [on/off]; - pause: Flow Control Pause Time; - eee_timer: tx EEE timer; - chain_mode: select chain mode instead of ring. - -3) Command line options -Driver parameters can be also passed in command line by using: - stmmaceth=watchdog:100,chain_mode=1 - -4) Driver information and notes - -4.1) Transmit process -The xmit method is invoked when the kernel needs to transmit a packet; it sets -the descriptors in the ring and informs the DMA engine, that there is a packet -ready to be transmitted. -By default, the driver sets the NETIF_F_SG bit in the features field of the -net_device structure, enabling the scatter-gather feature. This is true on -chips and configurations where the checksum can be done in hardware. -Once the controller has finished transmitting the packet, timer will be -scheduled to release the transmit resources. - -4.2) Receive process -When one or more packets are received, an interrupt happens. The interrupts -are not queued, so the driver has to scan all the descriptors in the ring during -the receive process. -This is based on NAPI, so the interrupt handler signals only if there is work -to be done, and it exits. -Then the poll method will be scheduled at some future point. -The incoming packets are stored, by the DMA, in a list of pre-allocated socket -buffers in order to avoid the memcpy (zero-copy). - -4.3) Interrupt mitigation -The driver is able to mitigate the number of its DMA interrupts -using NAPI for the reception on chips older than the 3.50. -New chips have an HW RX-Watchdog used for this mitigation. -Mitigation parameters can be tuned by ethtool. - -4.4) WOL -Wake up on Lan feature through Magic and Unicast frames are supported for the -GMAC core. - -4.5) DMA descriptors -Driver handles both normal and alternate descriptors. The latter has been only -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. - -4.5.1) Extended descriptors -The extended descriptors give us information about the Ethernet payload -when it is carrying PTP packets or TCP/UDP/ICMP over IP. -These are not available on GMAC Synopsys chips older than the 3.50. -At probe time the driver will decide if these can be actually used. -This support also is mandatory for PTPv2 because the extra descriptors -are used for saving the hardware timestamps and Extended Status. - -4.6) Ethtool support -Ethtool is supported. - -For example, driver statistics (including RMON), internal errors can be taken -using: - # ethtool -S ethX -command - -4.7) Jumbo and Segmentation Offloading -Jumbo frames are supported and tested for the GMAC. -The GSO has been also added but it's performed in software. -LRO is not supported. - -4.8) Physical -The driver is compatible with Physical Abstraction Layer to be connected with -PHY and GPHY devices. - -4.9) Platform information -Several information can be passed through the platform and device-tree. - -struct plat_stmmacenet_data { - char *phy_bus_name; - int bus_id; - int phy_addr; - int interface; - struct stmmac_mdio_bus_data *mdio_bus_data; - struct stmmac_dma_cfg *dma_cfg; - int clk_csr; - int has_gmac; - int enh_desc; - int tx_coe; - int rx_coe; - int bugged_jumbo; - int pmt; - int force_sf_dma_mode; - int force_thresh_dma_mode; - int riwt_off; - int max_speed; - int maxmtu; - void (*fix_mac_speed)(void *priv, unsigned int speed); - void (*bus_setup)(void __iomem *ioaddr); - 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: - o phy_bus_name: phy bus name to attach to the stmmac. - o bus_id: bus identifier. - o phy_addr: the physical address can be passed from the platform. - If it is set to -1 the driver will automatically - detect it at run-time by probing all the 32 addresses. - o interface: PHY device's interface. - o mdio_bus_data: specific platform fields for the MDIO bus. - o dma_cfg: internal DMA parameters - o pbl: the Programmable Burst Length is maximum number of beats to - be transferred in one DMA transaction. - GMAC also enables the 4xPBL by default. (8xPBL for GMAC 3.50 and newer) - o txpbl/rxpbl: GMAC and newer supports independent DMA pbl for tx/rx. - o pblx8: Enable 8xPBL (4xPBL for core rev < 3.50). Enabled by default. - o fixed_burst/mixed_burst/aal - o clk_csr: fixed CSR Clock range selection. - o has_gmac: uses the GMAC core. - o enh_desc: if sets the MAC will use the enhanced descriptor structure. - o tx_coe: core is able to perform the tx csum in HW. - o rx_coe: the supports three check sum offloading engine types: - type_1, type_2 (full csum) and no RX coe. - o bugged_jumbo: some HWs are not able to perform the csum in HW for - over-sized frames due to limited buffer sizes. - Setting this flag the csum will be done in SW on - JUMBO frames. - o pmt: core has the embedded power module (optional). - o force_sf_dma_mode: force DMA to use the Store and Forward mode - instead of the Threshold. - o force_thresh_dma_mode: force DMA to use the Threshold mode other than - the Store and Forward mode. - o riwt_off: force to disable the RX watchdog feature and switch to NAPI mode. - o fix_mac_speed: this callback is used for modifying some syscfg registers - (on ST SoCs) according to the link speed negotiated by the - physical layer . - o bus_setup: perform HW setup of the bus. For example, on some ST platforms - this field is used to configure the AMBA bridge to generate more - efficient STBus traffic. - o init/exit: callbacks used for calling a custom initialization; - this is sometime necessary on some platforms (e.g. ST boxes) - where the HW needs to have set some PIO lines or system cfg - 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: - - struct stmmac_mdio_bus_data { - int (*phy_reset)(void *priv); - unsigned int phy_mask; - int *irqs; - int probed_phy_irq; - }; - -Where: - o phy_reset: hook to reset the phy device attached to the bus. - o phy_mask: phy mask passed when register the MDIO bus within the driver. - o irqs: list of IRQs, one per PHY. - o probed_phy_irq: if irqs is NULL, use this for probed PHY. - -For DMA engine we have the following internal fields that should be -tuned according to the HW capabilities. - -struct stmmac_dma_cfg { - int pbl; - int txpbl; - int rxpbl; - bool pblx8; - int fixed_burst; - int mixed_burst; - bool aal; -}; - -Where: - o pbl: Programmable Burst Length (tx and rx) - o txpbl: Transmit Programmable Burst Length. Only for GMAC and newer. - If set, DMA tx will use this value rather than pbl. - o rxpbl: Receive Programmable Burst Length. Only for GMAC and newer. - If set, DMA rx will use this value rather than pbl. - o pblx8: Enable 8xPBL (4xPBL for core rev < 3.50). Enabled by default. - o fixed_burst: program the DMA to use the fixed burst mode - o mixed_burst: program the DMA to use the mixed burst mode - o aal: Address-Aligned Beats - ---- - -Below an example how the structures above are using on ST platforms. - - static struct plat_stmmacenet_data stxYYY_ethernet_platform_data = { - .has_gmac = 0, - .enh_desc = 0, - .fix_mac_speed = stxYYY_ethernet_fix_mac_speed, - | - |-> to write an internal syscfg - | on this platform when the - | link speed changes from 10 to - | 100 and viceversa - .init = &stmmac_claim_resource, - | - |-> On ST SoC this calls own "PAD" - | manager framework to claim - | all the resources necessary - | (GPIO ...). The .custom_cfg field - | is used to pass a custom config. -}; - -Below the usage of the stmmac_mdio_bus_data: on this SoC, in fact, -there are two MAC cores: one MAC is for MDIO Bus/PHY emulation -with fixed_link support. - -static struct stmmac_mdio_bus_data stmmac1_mdio_bus = { - .phy_reset = phy_reset; - | - |-> function to provide the phy_reset on this board - .phy_mask = 0, -}; - -static struct fixed_phy_status stmmac0_fixed_phy_status = { - .link = 1, - .speed = 100, - .duplex = 1, -}; - -During the board's device_init we can configure the first -MAC for fixed_link by calling: - fixed_phy_add(PHY_POLL, 1, &stmmac0_fixed_phy_status); -and the second one, with a real PHY device attached to the bus, -by using the stmmac_mdio_bus_data structure (to provide the id, the -reset procedure etc). - -Note that, starting from new chips, where it is available the HW capability -register, many configurations are discovered at run-time for example to -understand if EEE, HW csum, PTP, enhanced descriptor etc are actually -available. As strategy adopted in this driver, the information from the HW -capability register can replace what has been passed from the platform. - -4.10) Device-tree support. - -Please see the following document: - Documentation/devicetree/bindings/net/stmmac.txt - -4.11) This is a summary of the content of some relevant files: - o stmmac_main.c: implements the main network device driver; - o stmmac_mdio.c: provides MDIO functions; - o stmmac_pci: this is the PCI driver; - o stmmac_platform.c: this the platform driver (OF supported); - o stmmac_ethtool.c: implements 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 stmmac_pcs.h: Physical Coding Sublayer common implementation; - o dwmac-<XXX>.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; - o dwmac1000.h: specific header file for the dwmac GiGa; - o dwmac100_core: dwmac 100 core code; - o dwmac100_dma.c: dma functions for the dwmac 100 chip; - o dwmac1000.h: specific header file for the MAC; - o dwmac_lib.c: generic DMA functions; - 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; - -- 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 - -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 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 (please see: NETIF Msg Level). - -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) Precision Time Protocol (PTP) -The driver supports the IEEE 1588-2002, Precision Time Protocol (PTP), -which enables precise synchronization of clocks in measurement and -control systems implemented with technologies such as network -communication. - -In addition to the basic timestamp features mentioned in IEEE 1588-2002 -Timestamps, new GMAC cores support the advanced timestamp features. -IEEE 1588-2008 that can be enabled when configure the Kernel. - -8) SGMII/RGMII support -New GMAC devices provide own way to manage RGMII/SGMII. -This information is available at run-time by looking at the -HW capability register. This means that the stmmac can manage -auto-negotiation and link status w/o using the PHYLIB stuff. -In fact, the HW provides a subset of extended registers to -restart the ANE, verify Full/Half duplex mode and Speed. -Thanks to these registers, it is possible to look at the -Auto-negotiated Link Parter Ability. |