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1 | STMicroelectronics 10/100/1000 Synopsys Ethernet driver |
2 | ||
49cfbf67 | 3 | Copyright (C) 2007-2013 STMicroelectronics Ltd |
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4 | Author: Giuseppe Cavallaro <peppe.cavallaro@st.com> |
5 | ||
6 | This is the driver for the MAC 10/100/1000 on-chip Ethernet controllers | |
5b993268 | 7 | (Synopsys IP blocks). |
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8 | |
9 | Currently this network device driver is for all STM embedded MAC/GMAC | |
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10 | (i.e. 7xxx/5xxx SoCs), SPEAr (arm), Loongson1B (mips) and XLINX XC2V3000 |
11 | FF1152AMT0221 D1215994A VIRTEX FPGA board. | |
a1d6f3f6 | 12 | |
49cfbf67 | 13 | DWC Ether MAC 10/100/1000 Universal version 3.70a (and older) and DWC Ether |
3d237714 | 14 | MAC 10/100 Universal version 4.0 have been used for developing this driver. |
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15 | |
16 | This driver supports both the platform bus and PCI. | |
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17 | |
18 | Please, for more information also visit: www.stlinux.com | |
19 | ||
20 | 1) Kernel Configuration | |
21 | The kernel configuration option is STMMAC_ETH: | |
22 | Device Drivers ---> Network device support ---> Ethernet (1000 Mbit) ---> | |
23 | STMicroelectronics 10/100/1000 Ethernet driver (STMMAC_ETH) | |
24 | ||
25 | 2) Driver parameters list: | |
26 | debug: message level (0: no output, 16: all); | |
27 | phyaddr: to manually provide the physical address to the PHY device; | |
28 | dma_rxsize: DMA rx ring size; | |
29 | dma_txsize: DMA tx ring size; | |
30 | buf_sz: DMA buffer size; | |
31 | tc: control the HW FIFO threshold; | |
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32 | watchdog: transmit timeout (in milliseconds); |
33 | flow_ctrl: Flow control ability [on/off]; | |
34 | pause: Flow Control Pause Time; | |
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35 | eee_timer: tx EEE timer; |
36 | chain_mode: select chain mode instead of ring. | |
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37 | |
38 | 3) Command line options | |
39 | Driver parameters can be also passed in command line by using: | |
40 | stmmaceth=dma_rxsize:128,dma_txsize:512 | |
41 | ||
42 | 4) Driver information and notes | |
43 | ||
44 | 4.1) Transmit process | |
45 | The xmit method is invoked when the kernel needs to transmit a packet; it sets | |
46 | the descriptors in the ring and informs the DMA engine that there is a packet | |
47 | ready to be transmitted. | |
48 | Once the controller has finished transmitting the packet, an interrupt is | |
49 | triggered; So the driver will be able to release the socket buffers. | |
50 | By default, the driver sets the NETIF_F_SG bit in the features field of the | |
51 | net_device structure enabling the scatter/gather feature. | |
52 | ||
53 | 4.2) Receive process | |
54 | When one or more packets are received, an interrupt happens. The interrupts | |
55 | are not queued so the driver has to scan all the descriptors in the ring during | |
56 | the receive process. | |
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57 | This is based on NAPI so the interrupt handler signals only if there is work |
58 | to be done, and it exits. | |
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59 | Then the poll method will be scheduled at some future point. |
60 | The incoming packets are stored, by the DMA, in a list of pre-allocated socket | |
61 | buffers in order to avoid the memcpy (Zero-copy). | |
62 | ||
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63 | 4.3) Interrupt Mitigation |
64 | The driver is able to mitigate the number of its DMA interrupts | |
65 | using NAPI for the reception on chips older than the 3.50. | |
66 | New chips have an HW RX-Watchdog used for this mitigation. | |
67 | ||
68 | On Tx-side, the mitigation schema is based on a SW timer that calls the | |
69 | tx function (stmmac_tx) to reclaim the resource after transmitting the | |
70 | frames. | |
71 | Also there is another parameter (like a threshold) used to program | |
72 | the descriptors avoiding to set the interrupt on completion bit in | |
73 | when the frame is sent (xmit). | |
74 | ||
75 | Mitigation parameters can be tuned by ethtool. | |
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76 | |
77 | 4.4) WOL | |
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78 | Wake up on Lan feature through Magic and Unicast frames are supported for the |
79 | GMAC core. | |
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80 | |
81 | 4.5) DMA descriptors | |
82 | Driver handles both normal and enhanced descriptors. The latter has been only | |
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83 | tested on DWC Ether MAC 10/100/1000 Universal version 3.41a and later. |
84 | ||
85 | STMMAC supports DMA descriptor to operate both in dual buffer (RING) | |
86 | and linked-list(CHAINED) mode. In RING each descriptor points to two | |
87 | data buffer pointers whereas in CHAINED mode they point to only one data | |
88 | buffer pointer. RING mode is the default. | |
89 | ||
90 | In CHAINED mode each descriptor will have pointer to next descriptor in | |
91 | the list, hence creating the explicit chaining in the descriptor itself, | |
92 | whereas such explicit chaining is not possible in RING mode. | |
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93 | |
94 | 4.6) Ethtool support | |
95 | Ethtool is supported. Driver statistics and internal errors can be taken using: | |
96 | ethtool -S ethX command. It is possible to dump registers etc. | |
97 | ||
98 | 4.7) Jumbo and Segmentation Offloading | |
99 | Jumbo frames are supported and tested for the GMAC. | |
100 | The GSO has been also added but it's performed in software. | |
101 | LRO is not supported. | |
102 | ||
103 | 4.8) Physical | |
104 | The driver is compatible with PAL to work with PHY and GPHY devices. | |
105 | ||
106 | 4.9) Platform information | |
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107 | Several driver's information can be passed through the platform |
108 | These are included in the include/linux/stmmac.h header file | |
109 | and detailed below as well: | |
a1d6f3f6 | 110 | |
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111 | struct plat_stmmacenet_data { |
112 | char *phy_bus_name; | |
f5539b5b | 113 | int bus_id; |
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114 | int phy_addr; |
115 | int interface; | |
116 | struct stmmac_mdio_bus_data *mdio_bus_data; | |
8327eb65 | 117 | struct stmmac_dma_cfg *dma_cfg; |
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118 | int clk_csr; |
119 | int has_gmac; | |
120 | int enh_desc; | |
121 | int tx_coe; | |
55f9a4d6 | 122 | int rx_coe; |
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123 | int bugged_jumbo; |
124 | int pmt; | |
557e2a39 | 125 | int force_sf_dma_mode; |
e2a240c7 | 126 | int force_thresh_dma_mode; |
f9e01b55 | 127 | int riwt_off; |
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128 | void (*fix_mac_speed)(void *priv, unsigned int speed); |
129 | void (*bus_setup)(void __iomem *ioaddr); | |
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130 | void *(*setup)(struct platform_device *pdev); |
131 | int (*init)(struct platform_device *pdev, void *priv); | |
132 | void (*exit)(struct platform_device *pdev, void *priv); | |
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133 | void *custom_cfg; |
134 | void *custom_data; | |
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135 | void *bsp_priv; |
136 | }; | |
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137 | |
138 | Where: | |
3d237714 | 139 | o phy_bus_name: phy bus name to attach to the stmmac. |
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140 | o bus_id: bus identifier. |
141 | o phy_addr: the physical address can be passed from the platform. | |
142 | If it is set to -1 the driver will automatically | |
143 | detect it at run-time by probing all the 32 addresses. | |
144 | o interface: PHY device's interface. | |
145 | o mdio_bus_data: specific platform fields for the MDIO bus. | |
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146 | o dma_cfg: internal DMA parameters |
147 | o pbl: the Programmable Burst Length is maximum number of beats to | |
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148 | be transferred in one DMA transaction. |
149 | GMAC also enables the 4xPBL by default. | |
3d237714 | 150 | o fixed_burst/mixed_burst/burst_len |
cd7201f4 | 151 | o clk_csr: fixed CSR Clock range selection. |
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152 | o has_gmac: uses the GMAC core. |
153 | o enh_desc: if sets the MAC will use the enhanced descriptor structure. | |
154 | o tx_coe: core is able to perform the tx csum in HW. | |
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155 | o rx_coe: the supports three check sum offloading engine types: |
156 | type_1, type_2 (full csum) and no RX coe. | |
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157 | o bugged_jumbo: some HWs are not able to perform the csum in HW for |
158 | over-sized frames due to limited buffer sizes. | |
159 | Setting this flag the csum will be done in SW on | |
160 | JUMBO frames. | |
161 | o pmt: core has the embedded power module (optional). | |
162 | o force_sf_dma_mode: force DMA to use the Store and Forward mode | |
163 | instead of the Threshold. | |
c17cb8b5 | 164 | o force_thresh_dma_mode: force DMA to use the Threshold mode other than |
e2a240c7 | 165 | the Store and Forward mode. |
f9e01b55 | 166 | o riwt_off: force to disable the RX watchdog feature and switch to NAPI mode. |
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167 | o fix_mac_speed: this callback is used for modifying some syscfg registers |
168 | (on ST SoCs) according to the link speed negotiated by the | |
169 | physical layer . | |
170 | o bus_setup: perform HW setup of the bus. For example, on some ST platforms | |
171 | this field is used to configure the AMBA bridge to generate more | |
172 | efficient STBus traffic. | |
938dfdaa | 173 | o setup/init/exit: callbacks used for calling a custom initialization; |
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174 | this is sometime necessary on some platforms (e.g. ST boxes) |
175 | where the HW needs to have set some PIO lines or system cfg | |
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176 | registers. setup should return a pointer to private data, |
177 | which will be stored in bsp_priv, and then passed to init and | |
178 | exit callbacks. init/exit callbacks should not use or modify | |
179 | platform data. | |
3d237714 | 180 | o custom_cfg/custom_data: this is a custom configuration that can be passed |
49cfbf67 | 181 | while initializing the resources. |
c17cb8b5 | 182 | o bsp_priv: another private pointer. |
557e2a39 | 183 | |
8327eb65 | 184 | For MDIO bus The we have: |
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185 | |
186 | struct stmmac_mdio_bus_data { | |
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187 | int (*phy_reset)(void *priv); |
188 | unsigned int phy_mask; | |
189 | int *irqs; | |
190 | int probed_phy_irq; | |
191 | }; | |
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192 | |
193 | Where: | |
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194 | o phy_reset: hook to reset the phy device attached to the bus. |
195 | o phy_mask: phy mask passed when register the MDIO bus within the driver. | |
196 | o irqs: list of IRQs, one per PHY. | |
197 | o probed_phy_irq: if irqs is NULL, use this for probed PHY. | |
198 | ||
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199 | For DMA engine we have the following internal fields that should be |
200 | tuned according to the HW capabilities. | |
201 | ||
202 | struct stmmac_dma_cfg { | |
203 | int pbl; | |
204 | int fixed_burst; | |
205 | int burst_len_supported; | |
206 | }; | |
207 | ||
208 | Where: | |
209 | o pbl: Programmable Burst Length | |
210 | o fixed_burst: program the DMA to use the fixed burst mode | |
211 | o burst_len: this is the value we put in the register | |
212 | supported values are provided as macros in | |
213 | linux/stmmac.h header file. | |
214 | ||
215 | --- | |
216 | ||
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217 | Below an example how the structures above are using on ST platforms. |
218 | ||
219 | static struct plat_stmmacenet_data stxYYY_ethernet_platform_data = { | |
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220 | .has_gmac = 0, |
221 | .enh_desc = 0, | |
222 | .fix_mac_speed = stxYYY_ethernet_fix_mac_speed, | |
223 | | | |
224 | |-> to write an internal syscfg | |
225 | | on this platform when the | |
226 | | link speed changes from 10 to | |
227 | | 100 and viceversa | |
228 | .init = &stmmac_claim_resource, | |
229 | | | |
230 | |-> On ST SoC this calls own "PAD" | |
231 | | manager framework to claim | |
232 | | all the resources necessary | |
233 | | (GPIO ...). The .custom_cfg field | |
234 | | is used to pass a custom config. | |
235 | }; | |
236 | ||
237 | Below the usage of the stmmac_mdio_bus_data: on this SoC, in fact, | |
238 | there are two MAC cores: one MAC is for MDIO Bus/PHY emulation | |
239 | with fixed_link support. | |
240 | ||
241 | static struct stmmac_mdio_bus_data stmmac1_mdio_bus = { | |
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242 | .phy_reset = phy_reset; |
243 | | | |
244 | |-> function to provide the phy_reset on this board | |
245 | .phy_mask = 0, | |
246 | }; | |
247 | ||
248 | static struct fixed_phy_status stmmac0_fixed_phy_status = { | |
249 | .link = 1, | |
250 | .speed = 100, | |
251 | .duplex = 1, | |
252 | }; | |
253 | ||
254 | During the board's device_init we can configure the first | |
255 | MAC for fixed_link by calling: | |
256 | fixed_phy_add(PHY_POLL, 1, &stmmac0_fixed_phy_status));) | |
257 | and the second one, with a real PHY device attached to the bus, | |
258 | by using the stmmac_mdio_bus_data structure (to provide the id, the | |
259 | reset procedure etc). | |
260 | ||
261 | 4.10) List of source files: | |
262 | o Kconfig | |
263 | o Makefile | |
264 | o stmmac_main.c: main network device driver; | |
265 | o stmmac_mdio.c: mdio functions; | |
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266 | o stmmac_pci: PCI driver; |
267 | o stmmac_platform.c: platform driver | |
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268 | o stmmac_ethtool.c: ethtool support; |
269 | o stmmac_timer.[ch]: timer code used for mitigating the driver dma interrupts | |
0ec2ccd0 | 270 | (only tested on ST40 platforms based); |
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271 | o stmmac.h: private driver structure; |
272 | o common.h: common definitions and VFTs; | |
273 | o descs.h: descriptor structure definitions; | |
274 | o dwmac1000_core.c: GMAC core functions; | |
275 | o dwmac1000_dma.c: dma functions for the GMAC chip; | |
276 | o dwmac1000.h: specific header file for the GMAC; | |
277 | o dwmac100_core: MAC 100 core and dma code; | |
c17cb8b5 | 278 | o dwmac100_dma.c: dma functions for the MAC chip; |
557e2a39 | 279 | o dwmac1000.h: specific header file for the MAC; |
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280 | o dwmac_lib.c: generic DMA functions shared among chips; |
281 | o enh_desc.c: functions for handling enhanced descriptors; | |
282 | o norm_desc.c: functions for handling normal descriptors; | |
283 | o chain_mode.c/ring_mode.c:: functions to manage RING/CHAINED modes; | |
284 | o mmc_core.c/mmc.h: Management MAC Counters; | |
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285 | o stmmac_hwtstamp.c: HW timestamp support for PTP |
286 | o stmmac_ptp.c: PTP 1588 clock | |
557e2a39 | 287 | |
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288 | 5) Debug Information |
289 | ||
290 | The driver exports many information i.e. internal statistics, | |
291 | debug information, MAC and DMA registers etc. | |
292 | ||
293 | These can be read in several ways depending on the | |
294 | type of the information actually needed. | |
295 | ||
296 | For example a user can be use the ethtool support | |
297 | to get statistics: e.g. using: ethtool -S ethX | |
298 | (that shows the Management counters (MMC) if supported) | |
299 | or sees the MAC/DMA registers: e.g. using: ethtool -d ethX | |
300 | ||
301 | Compiling the Kernel with CONFIG_DEBUG_FS and enabling the | |
302 | STMMAC_DEBUG_FS option the driver will export the following | |
303 | debugfs entries: | |
304 | ||
305 | /sys/kernel/debug/stmmaceth/descriptors_status | |
306 | To show the DMA TX/RX descriptor rings | |
307 | ||
308 | Developer can also use the "debug" module parameter to get | |
309 | further debug information. | |
310 | ||
311 | In the end, there are other macros (that cannot be enabled | |
312 | via menuconfig) to turn-on the RX/TX DMA debugging, | |
313 | specific MAC core debug printk etc. Others to enable the | |
314 | debug in the TX and RX processes. | |
315 | All these are only useful during the developing stage | |
316 | and should never enabled inside the code for general usage. | |
317 | In fact, these can generate an huge amount of debug messages. | |
318 | ||
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319 | 6) Energy Efficient Ethernet |
320 | ||
321 | Energy Efficient Ethernet(EEE) enables IEEE 802.3 MAC sublayer along | |
322 | with a family of Physical layer to operate in the Low power Idle(LPI) | |
323 | mode. The EEE mode supports the IEEE 802.3 MAC operation at 100Mbps, | |
324 | 1000Mbps & 10Gbps. | |
325 | ||
326 | The LPI mode allows power saving by switching off parts of the | |
327 | communication device functionality when there is no data to be | |
328 | transmitted & received. The system on both the side of the link can | |
329 | disable some functionalities & save power during the period of low-link | |
330 | utilization. The MAC controls whether the system should enter or exit | |
331 | the LPI mode & communicate this to PHY. | |
332 | ||
333 | As soon as the interface is opened, the driver verifies if the EEE can | |
334 | be supported. This is done by looking at both the DMA HW capability | |
335 | register and the PHY devices MCD registers. | |
336 | To enter in Tx LPI mode the driver needs to have a software timer | |
337 | that enable and disable the LPI mode when there is nothing to be | |
338 | transmitted. | |
339 | ||
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340 | 7) Extended descriptors |
341 | The extended descriptors give us information about the receive Ethernet payload | |
342 | when it is carrying PTP packets or TCP/UDP/ICMP over IP. | |
343 | These are not available on GMAC Synopsys chips older than the 3.50. | |
344 | At probe time the driver will decide if these can be actually used. | |
345 | This support also is mandatory for PTPv2 because the extra descriptors 6 and 7 | |
346 | are used for saving the hardware timestamps. | |
347 | ||
348 | 8) Precision Time Protocol (PTP) | |
349 | The driver supports the IEEE 1588-2002, Precision Time Protocol (PTP), | |
350 | which enables precise synchronization of clocks in measurement and | |
351 | control systems implemented with technologies such as network | |
352 | communication. | |
353 | ||
354 | In addition to the basic timestamp features mentioned in IEEE 1588-2002 | |
355 | Timestamps, new GMAC cores support the advanced timestamp features. | |
356 | IEEE 1588-2008 that can be enabled when configure the Kernel. | |
357 | ||
358 | 9) SGMII/RGMII supports | |
359 | New GMAC devices provide own way to manage RGMII/SGMII. | |
360 | This information is available at run-time by looking at the | |
361 | HW capability register. This means that the stmmac can manage | |
362 | auto-negotiation and link status w/o using the PHYLIB stuff | |
363 | In fact, the HW provides a subset of extended registers to | |
364 | restart the ANE, verify Full/Half duplex mode and Speed. | |
365 | Also thanks to these registers it is possible to look at the | |
366 | Auto-negotiated Link Parter Ability. | |
367 | ||
368 | 10) TODO: | |
557e2a39 | 369 | o XGMAC is not supported. |
94fbbbf8 | 370 | o Complete the TBI & RTBI support. |
c17cb8b5 | 371 | o extend VLAN support for 3.70a SYNP GMAC. |