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author | Jeff Garzik <jgarzik@pobox.com> | 2005-09-01 18:02:01 -0400 |
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committer | Jeff Garzik <jgarzik@pobox.com> | 2005-09-01 18:02:01 -0400 |
commit | e3ee3b78f83688a0ae4315e8be71b2eac559904a (patch) | |
tree | deb03bcdd020262af450ed23382d7c921263f5cf /Documentation/networking | |
parent | 91cb70c1769d9b72dd1efe40c31f01005820b09e (diff) | |
parent | 6b39374a27eb4be7e9d82145ae270ba02ea90dc8 (diff) |
/spare/repo/netdev-2.6 branch 'master'
Diffstat (limited to 'Documentation/networking')
-rw-r--r-- | Documentation/networking/cxgb.txt | 352 | ||||
-rw-r--r-- | Documentation/networking/phy.txt | 288 |
2 files changed, 640 insertions, 0 deletions
diff --git a/Documentation/networking/cxgb.txt b/Documentation/networking/cxgb.txt new file mode 100644 index 000000000000..76324638626b --- /dev/null +++ b/Documentation/networking/cxgb.txt | |||
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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 | |||
9 | CONTENTS | ||
10 | ======== | ||
11 | INTRODUCTION | ||
12 | FEATURES | ||
13 | PERFORMANCE | ||
14 | DRIVER MESSAGES | ||
15 | KNOWN ISSUES | ||
16 | SUPPORT | ||
17 | |||
18 | |||
19 | INTRODUCTION | ||
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 | |||
27 | FEATURES | ||
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 | |||
96 | PERFORMANCE | ||
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 | |||
181 | DRIVER 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 | |||
200 | KNOWN 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 | |||
323 | SUPPORT | ||
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 | |||
338 | This program is free software; you can redistribute it and/or modify | ||
339 | it under the terms of the GNU General Public License, version 2, as | ||
340 | published by the Free Software Foundation. | ||
341 | |||
342 | You should have received a copy of the GNU General Public License along | ||
343 | with this program; if not, write to the Free Software Foundation, Inc., | ||
344 | 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | ||
345 | |||
346 | THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED | ||
347 | WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF | ||
348 | MERCHANTABILITY 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 | ------- | ||
3 | PHY Abstraction Layer | ||
4 | (Updated 2005-07-21) | ||
5 | |||
6 | Purpose | ||
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 | |||
34 | The 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 | |||
67 | Connecting 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 | |||
88 | Letting 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 | |||
134 | Keeping 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 | |||
148 | Doing 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 | |||
231 | PHY 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 | |||
237 | Generic 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 | |||
244 | Writing 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) | ||