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authorJeff Garzik <jgarzik@pobox.com>2005-09-01 18:02:01 -0400
committerJeff Garzik <jgarzik@pobox.com>2005-09-01 18:02:01 -0400
commite3ee3b78f83688a0ae4315e8be71b2eac559904a (patch)
treedeb03bcdd020262af450ed23382d7c921263f5cf /Documentation/networking
parent91cb70c1769d9b72dd1efe40c31f01005820b09e (diff)
parent6b39374a27eb4be7e9d82145ae270ba02ea90dc8 (diff)
/spare/repo/netdev-2.6 branch 'master'
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-rw-r--r--Documentation/networking/phy.txt288
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1 Chelsio N210 10Gb Ethernet Network Controller
2
3 Driver Release Notes for Linux
4
5 Version 2.1.1
6
7 June 20, 2005
8
9CONTENTS
10========
11 INTRODUCTION
12 FEATURES
13 PERFORMANCE
14 DRIVER MESSAGES
15 KNOWN ISSUES
16 SUPPORT
17
18
19INTRODUCTION
20============
21
22 This document describes the Linux driver for Chelsio 10Gb Ethernet Network
23 Controller. This driver supports the Chelsio N210 NIC and is backward
24 compatible with the Chelsio N110 model 10Gb NICs.
25
26
27FEATURES
28========
29
30 Adaptive Interrupts (adaptive-rx)
31 ---------------------------------
32
33 This feature provides an adaptive algorithm that adjusts the interrupt
34 coalescing parameters, allowing the driver to dynamically adapt the latency
35 settings to achieve the highest performance during various types of network
36 load.
37
38 The interface used to control this feature is ethtool. Please see the
39 ethtool manpage for additional usage information.
40
41 By default, adaptive-rx is disabled.
42 To enable adaptive-rx:
43
44 ethtool -C <interface> adaptive-rx on
45
46 To disable adaptive-rx, use ethtool:
47
48 ethtool -C <interface> adaptive-rx off
49
50 After disabling adaptive-rx, the timer latency value will be set to 50us.
51 You may set the timer latency after disabling adaptive-rx:
52
53 ethtool -C <interface> rx-usecs <microseconds>
54
55 An example to set the timer latency value to 100us on eth0:
56
57 ethtool -C eth0 rx-usecs 100
58
59 You may also provide a timer latency value while disabling adpative-rx:
60
61 ethtool -C <interface> adaptive-rx off rx-usecs <microseconds>
62
63 If adaptive-rx is disabled and a timer latency value is specified, the timer
64 will be set to the specified value until changed by the user or until
65 adaptive-rx is enabled.
66
67 To view the status of the adaptive-rx and timer latency values:
68
69 ethtool -c <interface>
70
71
72 TCP Segmentation Offloading (TSO) Support
73 -----------------------------------------
74
75 This feature, also known as "large send", enables a system's protocol stack
76 to offload portions of outbound TCP processing to a network interface card
77 thereby reducing system CPU utilization and enhancing performance.
78
79 The interface used to control this feature is ethtool version 1.8 or higher.
80 Please see the ethtool manpage for additional usage information.
81
82 By default, TSO is enabled.
83 To disable TSO:
84
85 ethtool -K <interface> tso off
86
87 To enable TSO:
88
89 ethtool -K <interface> tso on
90
91 To view the status of TSO:
92
93 ethtool -k <interface>
94
95
96PERFORMANCE
97===========
98
99 The following information is provided as an example of how to change system
100 parameters for "performance tuning" an what value to use. You may or may not
101 want to change these system parameters, depending on your server/workstation
102 application. Doing so is not warranted in any way by Chelsio Communications,
103 and is done at "YOUR OWN RISK". Chelsio will not be held responsible for loss
104 of data or damage to equipment.
105
106 Your distribution may have a different way of doing things, or you may prefer
107 a different method. These commands are shown only to provide an example of
108 what to do and are by no means definitive.
109
110 Making any of the following system changes will only last until you reboot
111 your system. You may want to write a script that runs at boot-up which
112 includes the optimal settings for your system.
113
114 Setting PCI Latency Timer:
115 setpci -d 1425:* 0x0c.l=0x0000F800
116
117 Disabling TCP timestamp:
118 sysctl -w net.ipv4.tcp_timestamps=0
119
120 Disabling SACK:
121 sysctl -w net.ipv4.tcp_sack=0
122
123 Setting large number of incoming connection requests:
124 sysctl -w net.ipv4.tcp_max_syn_backlog=3000
125
126 Setting maximum receive socket buffer size:
127 sysctl -w net.core.rmem_max=1024000
128
129 Setting maximum send socket buffer size:
130 sysctl -w net.core.wmem_max=1024000
131
132 Set smp_affinity (on a multiprocessor system) to a single CPU:
133 echo 1 > /proc/irq/<interrupt_number>/smp_affinity
134
135 Setting default receive socket buffer size:
136 sysctl -w net.core.rmem_default=524287
137
138 Setting default send socket buffer size:
139 sysctl -w net.core.wmem_default=524287
140
141 Setting maximum option memory buffers:
142 sysctl -w net.core.optmem_max=524287
143
144 Setting maximum backlog (# of unprocessed packets before kernel drops):
145 sysctl -w net.core.netdev_max_backlog=300000
146
147 Setting TCP read buffers (min/default/max):
148 sysctl -w net.ipv4.tcp_rmem="10000000 10000000 10000000"
149
150 Setting TCP write buffers (min/pressure/max):
151 sysctl -w net.ipv4.tcp_wmem="10000000 10000000 10000000"
152
153 Setting TCP buffer space (min/pressure/max):
154 sysctl -w net.ipv4.tcp_mem="10000000 10000000 10000000"
155
156 TCP window size for single connections:
157 The receive buffer (RX_WINDOW) size must be at least as large as the
158 Bandwidth-Delay Product of the communication link between the sender and
159 receiver. Due to the variations of RTT, you may want to increase the buffer
160 size up to 2 times the Bandwidth-Delay Product. Reference page 289 of
161 "TCP/IP Illustrated, Volume 1, The Protocols" by W. Richard Stevens.
162 At 10Gb speeds, use the following formula:
163 RX_WINDOW >= 1.25MBytes * RTT(in milliseconds)
164 Example for RTT with 100us: RX_WINDOW = (1,250,000 * 0.1) = 125,000
165 RX_WINDOW sizes of 256KB - 512KB should be sufficient.
166 Setting the min, max, and default receive buffer (RX_WINDOW) size:
167 sysctl -w net.ipv4.tcp_rmem="<min> <default> <max>"
168
169 TCP window size for multiple connections:
170 The receive buffer (RX_WINDOW) size may be calculated the same as single
171 connections, but should be divided by the number of connections. The
172 smaller window prevents congestion and facilitates better pacing,
173 especially if/when MAC level flow control does not work well or when it is
174 not supported on the machine. Experimentation may be necessary to attain
175 the correct value. This method is provided as a starting point fot the
176 correct receive buffer size.
177 Setting the min, max, and default receive buffer (RX_WINDOW) size is
178 performed in the same manner as single connection.
179
180
181DRIVER MESSAGES
182===============
183
184 The following messages are the most common messages logged by syslog. These
185 may be found in /var/log/messages.
186
187 Driver up:
188 Chelsio Network Driver - version 2.1.1
189
190 NIC detected:
191 eth#: Chelsio N210 1x10GBaseX NIC (rev #), PCIX 133MHz/64-bit
192
193 Link up:
194 eth#: link is up at 10 Gbps, full duplex
195
196 Link down:
197 eth#: link is down
198
199
200KNOWN ISSUES
201============
202
203 These issues have been identified during testing. The following information
204 is provided as a workaround to the problem. In some cases, this problem is
205 inherent to Linux or to a particular Linux Distribution and/or hardware
206 platform.
207
208 1. Large number of TCP retransmits on a multiprocessor (SMP) system.
209
210 On a system with multiple CPUs, the interrupt (IRQ) for the network
211 controller may be bound to more than one CPU. This will cause TCP
212 retransmits if the packet data were to be split across different CPUs
213 and re-assembled in a different order than expected.
214
215 To eliminate the TCP retransmits, set smp_affinity on the particular
216 interrupt to a single CPU. You can locate the interrupt (IRQ) used on
217 the N110/N210 by using ifconfig:
218 ifconfig <dev_name> | grep Interrupt
219 Set the smp_affinity to a single CPU:
220 echo 1 > /proc/irq/<interrupt_number>/smp_affinity
221
222 It is highly suggested that you do not run the irqbalance daemon on your
223 system, as this will change any smp_affinity setting you have applied.
224 The irqbalance daemon runs on a 10 second interval and binds interrupts
225 to the least loaded CPU determined by the daemon. To disable this daemon:
226 chkconfig --level 2345 irqbalance off
227
228 By default, some Linux distributions enable the kernel feature,
229 irqbalance, which performs the same function as the daemon. To disable
230 this feature, add the following line to your bootloader:
231 noirqbalance
232
233 Example using the Grub bootloader:
234 title Red Hat Enterprise Linux AS (2.4.21-27.ELsmp)
235 root (hd0,0)
236 kernel /vmlinuz-2.4.21-27.ELsmp ro root=/dev/hda3 noirqbalance
237 initrd /initrd-2.4.21-27.ELsmp.img
238
239 2. After running insmod, the driver is loaded and the incorrect network
240 interface is brought up without running ifup.
241
242 When using 2.4.x kernels, including RHEL kernels, the Linux kernel
243 invokes a script named "hotplug". This script is primarily used to
244 automatically bring up USB devices when they are plugged in, however,
245 the script also attempts to automatically bring up a network interface
246 after loading the kernel module. The hotplug script does this by scanning
247 the ifcfg-eth# config files in /etc/sysconfig/network-scripts, looking
248 for HWADDR=<mac_address>.
249
250 If the hotplug script does not find the HWADDRR within any of the
251 ifcfg-eth# files, it will bring up the device with the next available
252 interface name. If this interface is already configured for a different
253 network card, your new interface will have incorrect IP address and
254 network settings.
255
256 To solve this issue, you can add the HWADDR=<mac_address> key to the
257 interface config file of your network controller.
258
259 To disable this "hotplug" feature, you may add the driver (module name)
260 to the "blacklist" file located in /etc/hotplug. It has been noted that
261 this does not work for network devices because the net.agent script
262 does not use the blacklist file. Simply remove, or rename, the net.agent
263 script located in /etc/hotplug to disable this feature.
264
265 3. Transport Protocol (TP) hangs when running heavy multi-connection traffic
266 on an AMD Opteron system with HyperTransport PCI-X Tunnel chipset.
267
268 If your AMD Opteron system uses the AMD-8131 HyperTransport PCI-X Tunnel
269 chipset, you may experience the "133-Mhz Mode Split Completion Data
270 Corruption" bug identified by AMD while using a 133Mhz PCI-X card on the
271 bus PCI-X bus.
272
273 AMD states, "Under highly specific conditions, the AMD-8131 PCI-X Tunnel
274 can provide stale data via split completion cycles to a PCI-X card that
275 is operating at 133 Mhz", causing data corruption.
276
277 AMD's provides three workarounds for this problem, however, Chelsio
278 recommends the first option for best performance with this bug:
279
280 For 133Mhz secondary bus operation, limit the transaction length and
281 the number of outstanding transactions, via BIOS configuration
282 programming of the PCI-X card, to the following:
283
284 Data Length (bytes): 1k
285 Total allowed outstanding transactions: 2
286
287 Please refer to AMD 8131-HT/PCI-X Errata 26310 Rev 3.08 August 2004,
288 section 56, "133-MHz Mode Split Completion Data Corruption" for more
289 details with this bug and workarounds suggested by AMD.
290
291 It may be possible to work outside AMD's recommended PCI-X settings, try
292 increasing the Data Length to 2k bytes for increased performance. If you
293 have issues with these settings, please revert to the "safe" settings
294 and duplicate the problem before submitting a bug or asking for support.
295
296 NOTE: The default setting on most systems is 8 outstanding transactions
297 and 2k bytes data length.
298
299 4. On multiprocessor systems, it has been noted that an application which
300 is handling 10Gb networking can switch between CPUs causing degraded
301 and/or unstable performance.
302
303 If running on an SMP system and taking performance measurements, it
304 is suggested you either run the latest netperf-2.4.0+ or use a binding
305 tool such as Tim Hockin's procstate utilities (runon)
306 <http://www.hockin.org/~thockin/procstate/>.
307
308 Binding netserver and netperf (or other applications) to particular
309 CPUs will have a significant difference in performance measurements.
310 You may need to experiment which CPU to bind the application to in
311 order to achieve the best performance for your system.
312
313 If you are developing an application designed for 10Gb networking,
314 please keep in mind you may want to look at kernel functions
315 sched_setaffinity & sched_getaffinity to bind your application.
316
317 If you are just running user-space applications such as ftp, telnet,
318 etc., you may want to try the runon tool provided by Tim Hockin's
319 procstate utility. You could also try binding the interface to a
320 particular CPU: runon 0 ifup eth0
321
322
323SUPPORT
324=======
325
326 If you have problems with the software or hardware, please contact our
327 customer support team via email at support@chelsio.com or check our website
328 at http://www.chelsio.com
329
330===============================================================================
331
332 Chelsio Communications
333 370 San Aleso Ave.
334 Suite 100
335 Sunnyvale, CA 94085
336 http://www.chelsio.com
337
338This program is free software; you can redistribute it and/or modify
339it under the terms of the GNU General Public License, version 2, as
340published by the Free Software Foundation.
341
342You should have received a copy of the GNU General Public License along
343with this program; if not, write to the Free Software Foundation, Inc.,
34459 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
345
346THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
347WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
348MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
349
350 Copyright (c) 2003-2005 Chelsio Communications. All rights reserved.
351
352===============================================================================
diff --git a/Documentation/networking/phy.txt b/Documentation/networking/phy.txt
new file mode 100644
index 000000000000..29ccae409031
--- /dev/null
+++ b/Documentation/networking/phy.txt
@@ -0,0 +1,288 @@
1
2-------
3PHY Abstraction Layer
4(Updated 2005-07-21)
5
6Purpose
7
8 Most network devices consist of set of registers which provide an interface
9 to a MAC layer, which communicates with the physical connection through a
10 PHY. The PHY concerns itself with negotiating link parameters with the link
11 partner on the other side of the network connection (typically, an ethernet
12 cable), and provides a register interface to allow drivers to determine what
13 settings were chosen, and to configure what settings are allowed.
14
15 While these devices are distinct from the network devices, and conform to a
16 standard layout for the registers, it has been common practice to integrate
17 the PHY management code with the network driver. This has resulted in large
18 amounts of redundant code. Also, on embedded systems with multiple (and
19 sometimes quite different) ethernet controllers connected to the same
20 management bus, it is difficult to ensure safe use of the bus.
21
22 Since the PHYs are devices, and the management busses through which they are
23 accessed are, in fact, busses, the PHY Abstraction Layer treats them as such.
24 In doing so, it has these goals:
25
26 1) Increase code-reuse
27 2) Increase overall code-maintainability
28 3) Speed development time for new network drivers, and for new systems
29
30 Basically, this layer is meant to provide an interface to PHY devices which
31 allows network driver writers to write as little code as possible, while
32 still providing a full feature set.
33
34The MDIO bus
35
36 Most network devices are connected to a PHY by means of a management bus.
37 Different devices use different busses (though some share common interfaces).
38 In order to take advantage of the PAL, each bus interface needs to be
39 registered as a distinct device.
40
41 1) read and write functions must be implemented. Their prototypes are:
42
43 int write(struct mii_bus *bus, int mii_id, int regnum, u16 value);
44 int read(struct mii_bus *bus, int mii_id, int regnum);
45
46 mii_id is the address on the bus for the PHY, and regnum is the register
47 number. These functions are guaranteed not to be called from interrupt
48 time, so it is safe for them to block, waiting for an interrupt to signal
49 the operation is complete
50
51 2) A reset function is necessary. This is used to return the bus to an
52 initialized state.
53
54 3) A probe function is needed. This function should set up anything the bus
55 driver needs, setup the mii_bus structure, and register with the PAL using
56 mdiobus_register. Similarly, there's a remove function to undo all of
57 that (use mdiobus_unregister).
58
59 4) Like any driver, the device_driver structure must be configured, and init
60 exit functions are used to register the driver.
61
62 5) The bus must also be declared somewhere as a device, and registered.
63
64 As an example for how one driver implemented an mdio bus driver, see
65 drivers/net/gianfar_mii.c and arch/ppc/syslib/mpc85xx_devices.c
66
67Connecting to a PHY
68
69 Sometime during startup, the network driver needs to establish a connection
70 between the PHY device, and the network device. At this time, the PHY's bus
71 and drivers need to all have been loaded, so it is ready for the connection.
72 At this point, there are several ways to connect to the PHY:
73
74 1) The PAL handles everything, and only calls the network driver when
75 the link state changes, so it can react.
76
77 2) The PAL handles everything except interrupts (usually because the
78 controller has the interrupt registers).
79
80 3) The PAL handles everything, but checks in with the driver every second,
81 allowing the network driver to react first to any changes before the PAL
82 does.
83
84 4) The PAL serves only as a library of functions, with the network device
85 manually calling functions to update status, and configure the PHY
86
87
88Letting the PHY Abstraction Layer do Everything
89
90 If you choose option 1 (The hope is that every driver can, but to still be
91 useful to drivers that can't), connecting to the PHY is simple:
92
93 First, you need a function to react to changes in the link state. This
94 function follows this protocol:
95
96 static void adjust_link(struct net_device *dev);
97
98 Next, you need to know the device name of the PHY connected to this device.
99 The name will look something like, "phy0:0", where the first number is the
100 bus id, and the second is the PHY's address on that bus.
101
102 Now, to connect, just call this function:
103
104 phydev = phy_connect(dev, phy_name, &adjust_link, flags);
105
106 phydev is a pointer to the phy_device structure which represents the PHY. If
107 phy_connect is successful, it will return the pointer. dev, here, is the
108 pointer to your net_device. Once done, this function will have started the
109 PHY's software state machine, and registered for the PHY's interrupt, if it
110 has one. The phydev structure will be populated with information about the
111 current state, though the PHY will not yet be truly operational at this
112 point.
113
114 flags is a u32 which can optionally contain phy-specific flags.
115 This is useful if the system has put hardware restrictions on
116 the PHY/controller, of which the PHY needs to be aware.
117
118 Now just make sure that phydev->supported and phydev->advertising have any
119 values pruned from them which don't make sense for your controller (a 10/100
120 controller may be connected to a gigabit capable PHY, so you would need to
121 mask off SUPPORTED_1000baseT*). See include/linux/ethtool.h for definitions
122 for these bitfields. Note that you should not SET any bits, or the PHY may
123 get put into an unsupported state.
124
125 Lastly, once the controller is ready to handle network traffic, you call
126 phy_start(phydev). This tells the PAL that you are ready, and configures the
127 PHY to connect to the network. If you want to handle your own interrupts,
128 just set phydev->irq to PHY_IGNORE_INTERRUPT before you call phy_start.
129 Similarly, if you don't want to use interrupts, set phydev->irq to PHY_POLL.
130
131 When you want to disconnect from the network (even if just briefly), you call
132 phy_stop(phydev).
133
134Keeping Close Tabs on the PAL
135
136 It is possible that the PAL's built-in state machine needs a little help to
137 keep your network device and the PHY properly in sync. If so, you can
138 register a helper function when connecting to the PHY, which will be called
139 every second before the state machine reacts to any changes. To do this, you
140 need to manually call phy_attach() and phy_prepare_link(), and then call
141 phy_start_machine() with the second argument set to point to your special
142 handler.
143
144 Currently there are no examples of how to use this functionality, and testing
145 on it has been limited because the author does not have any drivers which use
146 it (they all use option 1). So Caveat Emptor.
147
148Doing it all yourself
149
150 There's a remote chance that the PAL's built-in state machine cannot track
151 the complex interactions between the PHY and your network device. If this is
152 so, you can simply call phy_attach(), and not call phy_start_machine or
153 phy_prepare_link(). This will mean that phydev->state is entirely yours to
154 handle (phy_start and phy_stop toggle between some of the states, so you
155 might need to avoid them).
156
157 An effort has been made to make sure that useful functionality can be
158 accessed without the state-machine running, and most of these functions are
159 descended from functions which did not interact with a complex state-machine.
160 However, again, no effort has been made so far to test running without the
161 state machine, so tryer beware.
162
163 Here is a brief rundown of the functions:
164
165 int phy_read(struct phy_device *phydev, u16 regnum);
166 int phy_write(struct phy_device *phydev, u16 regnum, u16 val);
167
168 Simple read/write primitives. They invoke the bus's read/write function
169 pointers.
170
171 void phy_print_status(struct phy_device *phydev);
172
173 A convenience function to print out the PHY status neatly.
174
175 int phy_clear_interrupt(struct phy_device *phydev);
176 int phy_config_interrupt(struct phy_device *phydev, u32 interrupts);
177
178 Clear the PHY's interrupt, and configure which ones are allowed,
179 respectively. Currently only supports all on, or all off.
180
181 int phy_enable_interrupts(struct phy_device *phydev);
182 int phy_disable_interrupts(struct phy_device *phydev);
183
184 Functions which enable/disable PHY interrupts, clearing them
185 before and after, respectively.
186
187 int phy_start_interrupts(struct phy_device *phydev);
188 int phy_stop_interrupts(struct phy_device *phydev);
189
190 Requests the IRQ for the PHY interrupts, then enables them for
191 start, or disables then frees them for stop.
192
193 struct phy_device * phy_attach(struct net_device *dev, const char *phy_id,
194 u32 flags);
195
196 Attaches a network device to a particular PHY, binding the PHY to a generic
197 driver if none was found during bus initialization. Passes in
198 any phy-specific flags as needed.
199
200 int phy_start_aneg(struct phy_device *phydev);
201
202 Using variables inside the phydev structure, either configures advertising
203 and resets autonegotiation, or disables autonegotiation, and configures
204 forced settings.
205
206 static inline int phy_read_status(struct phy_device *phydev);
207
208 Fills the phydev structure with up-to-date information about the current
209 settings in the PHY.
210
211 void phy_sanitize_settings(struct phy_device *phydev)
212
213 Resolves differences between currently desired settings, and
214 supported settings for the given PHY device. Does not make
215 the changes in the hardware, though.
216
217 int phy_ethtool_sset(struct phy_device *phydev, struct ethtool_cmd *cmd);
218 int phy_ethtool_gset(struct phy_device *phydev, struct ethtool_cmd *cmd);
219
220 Ethtool convenience functions.
221
222 int phy_mii_ioctl(struct phy_device *phydev,
223 struct mii_ioctl_data *mii_data, int cmd);
224
225 The MII ioctl. Note that this function will completely screw up the state
226 machine if you write registers like BMCR, BMSR, ADVERTISE, etc. Best to
227 use this only to write registers which are not standard, and don't set off
228 a renegotiation.
229
230
231PHY Device Drivers
232
233 With the PHY Abstraction Layer, adding support for new PHYs is
234 quite easy. In some cases, no work is required at all! However,
235 many PHYs require a little hand-holding to get up-and-running.
236
237Generic PHY driver
238
239 If the desired PHY doesn't have any errata, quirks, or special
240 features you want to support, then it may be best to not add
241 support, and let the PHY Abstraction Layer's Generic PHY Driver
242 do all of the work.
243
244Writing a PHY driver
245
246 If you do need to write a PHY driver, the first thing to do is
247 make sure it can be matched with an appropriate PHY device.
248 This is done during bus initialization by reading the device's
249 UID (stored in registers 2 and 3), then comparing it to each
250 driver's phy_id field by ANDing it with each driver's
251 phy_id_mask field. Also, it needs a name. Here's an example:
252
253 static struct phy_driver dm9161_driver = {
254 .phy_id = 0x0181b880,
255 .name = "Davicom DM9161E",
256 .phy_id_mask = 0x0ffffff0,
257 ...
258 }
259
260 Next, you need to specify what features (speed, duplex, autoneg,
261 etc) your PHY device and driver support. Most PHYs support
262 PHY_BASIC_FEATURES, but you can look in include/mii.h for other
263 features.
264
265 Each driver consists of a number of function pointers:
266
267 config_init: configures PHY into a sane state after a reset.
268 For instance, a Davicom PHY requires descrambling disabled.
269 probe: Does any setup needed by the driver
270 suspend/resume: power management
271 config_aneg: Changes the speed/duplex/negotiation settings
272 read_status: Reads the current speed/duplex/negotiation settings
273 ack_interrupt: Clear a pending interrupt
274 config_intr: Enable or disable interrupts
275 remove: Does any driver take-down
276
277 Of these, only config_aneg and read_status are required to be
278 assigned by the driver code. The rest are optional. Also, it is
279 preferred to use the generic phy driver's versions of these two
280 functions if at all possible: genphy_read_status and
281 genphy_config_aneg. If this is not possible, it is likely that
282 you only need to perform some actions before and after invoking
283 these functions, and so your functions will wrap the generic
284 ones.
285
286 Feel free to look at the Marvell, Cicada, and Davicom drivers in
287 drivers/net/phy/ for examples (the lxt and qsemi drivers have
288 not been tested as of this writing)