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Based on kernel version 3.15.4. Page generated on 2014-07-07 09:04 EST.

1	DM9000 Network driver
2	=====================
3	
4	Copyright 2008 Simtec Electronics,
5		  Ben Dooks <ben@simtec.co.uk> <ben-linux@fluff.org>
6	
7	
8	Introduction
9	------------
10	
11	This file describes how to use the DM9000 platform-device based network driver
12	that is contained in the files drivers/net/dm9000.c and drivers/net/dm9000.h.
13	
14	The driver supports three DM9000 variants, the DM9000E which is the first chip
15	supported as well as the newer DM9000A and DM9000B devices. It is currently
16	maintained and tested by Ben Dooks, who should be CC: to any patches for this
17	driver.
18	
19	
20	Defining the platform device
21	----------------------------
22	
23	The minimum set of resources attached to the platform device are as follows:
24	
25	    1) The physical address of the address register
26	    2) The physical address of the data register
27	    3) The IRQ line the device's interrupt pin is connected to.
28	
29	These resources should be specified in that order, as the ordering of the
30	two address regions is important (the driver expects these to be address
31	and then data).
32	
33	An example from arch/arm/mach-s3c2410/mach-bast.c is:
34	
35	static struct resource bast_dm9k_resource[] = {
36		[0] = {
37			.start = S3C2410_CS5 + BAST_PA_DM9000,
38			.end   = S3C2410_CS5 + BAST_PA_DM9000 + 3,
39			.flags = IORESOURCE_MEM,
40		},
41		[1] = {
42			.start = S3C2410_CS5 + BAST_PA_DM9000 + 0x40,
43			.end   = S3C2410_CS5 + BAST_PA_DM9000 + 0x40 + 0x3f,
44			.flags = IORESOURCE_MEM,
45		},
46		[2] = {
47			.start = IRQ_DM9000,
48			.end   = IRQ_DM9000,
49			.flags = IORESOURCE_IRQ | IORESOURCE_IRQ_HIGHLEVEL,
50		}
51	};
52	
53	static struct platform_device bast_device_dm9k = {
54		.name		= "dm9000",
55		.id		= 0,
56		.num_resources	= ARRAY_SIZE(bast_dm9k_resource),
57		.resource	= bast_dm9k_resource,
58	};
59	
60	Note the setting of the IRQ trigger flag in bast_dm9k_resource[2].flags,
61	as this will generate a warning if it is not present. The trigger from
62	the flags field will be passed to request_irq() when registering the IRQ
63	handler to ensure that the IRQ is setup correctly.
64	
65	This shows a typical platform device, without the optional configuration
66	platform data supplied. The next example uses the same resources, but adds
67	the optional platform data to pass extra configuration data:
68	
69	static struct dm9000_plat_data bast_dm9k_platdata = {
70		.flags		= DM9000_PLATF_16BITONLY,
71	};
72	
73	static struct platform_device bast_device_dm9k = {
74		.name		= "dm9000",
75		.id		= 0,
76		.num_resources	= ARRAY_SIZE(bast_dm9k_resource),
77		.resource	= bast_dm9k_resource,
78		.dev		= {
79			.platform_data = &bast_dm9k_platdata,
80		}
81	};
82	
83	The platform data is defined in include/linux/dm9000.h and described below.
84	
85	
86	Platform data
87	-------------
88	
89	Extra platform data for the DM9000 can describe the IO bus width to the
90	device, whether or not an external PHY is attached to the device and
91	the availability of an external configuration EEPROM.
92	
93	The flags for the platform data .flags field are as follows:
94	
95	DM9000_PLATF_8BITONLY
96	
97		The IO should be done with 8bit operations.
98	
99	DM9000_PLATF_16BITONLY
100	
101		The IO should be done with 16bit operations.
102	
103	DM9000_PLATF_32BITONLY
104	
105		The IO should be done with 32bit operations.
106	
107	DM9000_PLATF_EXT_PHY
108	
109		The chip is connected to an external PHY.
110	
111	DM9000_PLATF_NO_EEPROM
112	
113		This can be used to signify that the board does not have an
114		EEPROM, or that the EEPROM should be hidden from the user.
115	
116	DM9000_PLATF_SIMPLE_PHY
117	
118		Switch to using the simpler PHY polling method which does not
119		try and read the MII PHY state regularly. This is only available
120		when using the internal PHY. See the section on link state polling
121		for more information.
122	
123		The config symbol DM9000_FORCE_SIMPLE_PHY_POLL, Kconfig entry
124		"Force simple NSR based PHY polling" allows this flag to be
125		forced on at build time.
126	
127	
128	PHY Link state polling
129	----------------------
130	
131	The driver keeps track of the link state and informs the network core
132	about link (carrier) availability. This is managed by several methods
133	depending on the version of the chip and on which PHY is being used.
134	
135	For the internal PHY, the original (and currently default) method is
136	to read the MII state, either when the status changes if we have the
137	necessary interrupt support in the chip or every two seconds via a
138	periodic timer.
139	
140	To reduce the overhead for the internal PHY, there is now the option
141	of using the DM9000_FORCE_SIMPLE_PHY_POLL config, or DM9000_PLATF_SIMPLE_PHY
142	platform data option to read the summary information without the
143	expensive MII accesses. This method is faster, but does not print
144	as much information.
145	
146	When using an external PHY, the driver currently has to poll the MII
147	link status as there is no method for getting an interrupt on link change.
148	
149	
150	DM9000A / DM9000B
151	-----------------
152	
153	These chips are functionally similar to the DM9000E and are supported easily
154	by the same driver. The features are:
155	
156	   1) Interrupt on internal PHY state change. This means that the periodic
157	      polling of the PHY status may be disabled on these devices when using
158	      the internal PHY.
159	
160	   2) TCP/UDP checksum offloading, which the driver does not currently support.
161	
162	
163	ethtool
164	-------
165	
166	The driver supports the ethtool interface for access to the driver
167	state information, the PHY state and the EEPROM.
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