linux/Documentation/networking/dm9000.txt
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   1DM9000 Network driver
   2=====================
   3
   4Copyright 2008 Simtec Electronics,
   5          Ben Dooks <ben@simtec.co.uk> <ben-linux@fluff.org>
   6
   7
   8Introduction
   9------------
  10
  11This file describes how to use the DM9000 platform-device based network driver
  12that is contained in the files drivers/net/dm9000.c and drivers/net/dm9000.h.
  13
  14The driver supports three DM9000 variants, the DM9000E which is the first chip
  15supported as well as the newer DM9000A and DM9000B devices. It is currently
  16maintained and tested by Ben Dooks, who should be CC: to any patches for this
  17driver.
  18
  19
  20Defining the platform device
  21----------------------------
  22
  23The 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
  29These resources should be specified in that order, as the ordering of the
  30two address regions is important (the driver expects these to be address
  31and then data).
  32
  33An example from arch/arm/mach-s3c2410/mach-bast.c is:
  34
  35static 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
  53static 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
  60Note the setting of the IRQ trigger flag in bast_dm9k_resource[2].flags,
  61as this will generate a warning if it is not present. The trigger from
  62the flags field will be passed to request_irq() when registering the IRQ
  63handler to ensure that the IRQ is setup correctly.
  64
  65This shows a typical platform device, without the optional configuration
  66platform data supplied. The next example uses the same resources, but adds
  67the optional platform data to pass extra configuration data:
  68
  69static struct dm9000_plat_data bast_dm9k_platdata = {
  70        .flags          = DM9000_PLATF_16BITONLY,
  71};
  72
  73static 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
  83The platform data is defined in include/linux/dm9000.h and described below.
  84
  85
  86Platform data
  87-------------
  88
  89Extra platform data for the DM9000 can describe the IO bus width to the
  90device, whether or not an external PHY is attached to the device and
  91the availability of an external configuration EEPROM.
  92
  93The flags for the platform data .flags field are as follows:
  94
  95DM9000_PLATF_8BITONLY
  96
  97        The IO should be done with 8bit operations.
  98
  99DM9000_PLATF_16BITONLY
 100
 101        The IO should be done with 16bit operations.
 102
 103DM9000_PLATF_32BITONLY
 104
 105        The IO should be done with 32bit operations.
 106
 107DM9000_PLATF_EXT_PHY
 108
 109        The chip is connected to an external PHY.
 110
 111DM9000_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
 116DM9000_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
 128PHY Link state polling
 129----------------------
 130
 131The driver keeps track of the link state and informs the network core
 132about link (carrier) availability. This is managed by several methods
 133depending on the version of the chip and on which PHY is being used.
 134
 135For the internal PHY, the original (and currently default) method is
 136to read the MII state, either when the status changes if we have the
 137necessary interrupt support in the chip or every two seconds via a
 138periodic timer.
 139
 140To reduce the overhead for the internal PHY, there is now the option
 141of using the DM9000_FORCE_SIMPLE_PHY_POLL config, or DM9000_PLATF_SIMPLE_PHY
 142platform data option to read the summary information without the
 143expensive MII accesses. This method is faster, but does not print
 144as much information.
 145
 146When using an external PHY, the driver currently has to poll the MII
 147link status as there is no method for getting an interrupt on link change.
 148
 149
 150DM9000A / DM9000B
 151-----------------
 152
 153These chips are functionally similar to the DM9000E and are supported easily
 154by 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
 163ethtool
 164-------
 165
 166The driver supports the ethtool interface for access to the driver
 167state information, the PHY state and the EEPROM.
 168
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