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1.. SPDX-License-Identifier: GPL-2.02 3=====================4DM9000 Network driver5=====================6 7Copyright 2008 Simtec Electronics,8 9 Ben Dooks <ben@simtec.co.uk> <ben-linux@fluff.org>10 11 12Introduction13------------14 15This file describes how to use the DM9000 platform-device based network driver16that is contained in the files drivers/net/dm9000.c and drivers/net/dm9000.h.17 18The driver supports three DM9000 variants, the DM9000E which is the first chip19supported as well as the newer DM9000A and DM9000B devices. It is currently20maintained and tested by Ben Dooks, who should be CC: to any patches for this21driver.22 23 24Defining the platform device25----------------------------26 27The minimum set of resources attached to the platform device are as follows:28 29 1) The physical address of the address register30 2) The physical address of the data register31 3) The IRQ line the device's interrupt pin is connected to.32 33These resources should be specified in that order, as the ordering of the34two address regions is important (the driver expects these to be address35and then data).36 37An example from arch/arm/mach-s3c/mach-bast.c is::38 39 static struct resource bast_dm9k_resource[] = {40 [0] = {41 .start = S3C2410_CS5 + BAST_PA_DM9000,42 .end = S3C2410_CS5 + BAST_PA_DM9000 + 3,43 .flags = IORESOURCE_MEM,44 },45 [1] = {46 .start = S3C2410_CS5 + BAST_PA_DM9000 + 0x40,47 .end = S3C2410_CS5 + BAST_PA_DM9000 + 0x40 + 0x3f,48 .flags = IORESOURCE_MEM,49 },50 [2] = {51 .start = IRQ_DM9000,52 .end = IRQ_DM9000,53 .flags = IORESOURCE_IRQ | IORESOURCE_IRQ_HIGHLEVEL,54 }55 };56 57 static struct platform_device bast_device_dm9k = {58 .name = "dm9000",59 .id = 0,60 .num_resources = ARRAY_SIZE(bast_dm9k_resource),61 .resource = bast_dm9k_resource,62 };63 64Note the setting of the IRQ trigger flag in bast_dm9k_resource[2].flags,65as this will generate a warning if it is not present. The trigger from66the flags field will be passed to request_irq() when registering the IRQ67handler to ensure that the IRQ is setup correctly.68 69This shows a typical platform device, without the optional configuration70platform data supplied. The next example uses the same resources, but adds71the optional platform data to pass extra configuration data::72 73 static struct dm9000_plat_data bast_dm9k_platdata = {74 .flags = DM9000_PLATF_16BITONLY,75 };76 77 static struct platform_device bast_device_dm9k = {78 .name = "dm9000",79 .id = 0,80 .num_resources = ARRAY_SIZE(bast_dm9k_resource),81 .resource = bast_dm9k_resource,82 .dev = {83 .platform_data = &bast_dm9k_platdata,84 }85 };86 87The platform data is defined in include/linux/dm9000.h and described below.88 89 90Platform data91-------------92 93Extra platform data for the DM9000 can describe the IO bus width to the94device, whether or not an external PHY is attached to the device and95the availability of an external configuration EEPROM.96 97The flags for the platform data .flags field are as follows:98 99DM9000_PLATF_8BITONLY100 101 The IO should be done with 8bit operations.102 103DM9000_PLATF_16BITONLY104 105 The IO should be done with 16bit operations.106 107DM9000_PLATF_32BITONLY108 109 The IO should be done with 32bit operations.110 111DM9000_PLATF_EXT_PHY112 113 The chip is connected to an external PHY.114 115DM9000_PLATF_NO_EEPROM116 117 This can be used to signify that the board does not have an118 EEPROM, or that the EEPROM should be hidden from the user.119 120DM9000_PLATF_SIMPLE_PHY121 122 Switch to using the simpler PHY polling method which does not123 try and read the MII PHY state regularly. This is only available124 when using the internal PHY. See the section on link state polling125 for more information.126 127 The config symbol DM9000_FORCE_SIMPLE_PHY_POLL, Kconfig entry128 "Force simple NSR based PHY polling" allows this flag to be129 forced on at build time.130 131 132PHY Link state polling133----------------------134 135The driver keeps track of the link state and informs the network core136about link (carrier) availability. This is managed by several methods137depending on the version of the chip and on which PHY is being used.138 139For the internal PHY, the original (and currently default) method is140to read the MII state, either when the status changes if we have the141necessary interrupt support in the chip or every two seconds via a142periodic timer.143 144To reduce the overhead for the internal PHY, there is now the option145of using the DM9000_FORCE_SIMPLE_PHY_POLL config, or DM9000_PLATF_SIMPLE_PHY146platform data option to read the summary information without the147expensive MII accesses. This method is faster, but does not print148as much information.149 150When using an external PHY, the driver currently has to poll the MII151link status as there is no method for getting an interrupt on link change.152 153 154DM9000A / DM9000B155-----------------156 157These chips are functionally similar to the DM9000E and are supported easily158by the same driver. The features are:159 160 1) Interrupt on internal PHY state change. This means that the periodic161 polling of the PHY status may be disabled on these devices when using162 the internal PHY.163 164 2) TCP/UDP checksum offloading, which the driver does not currently support.165 166 167ethtool168-------169 170The driver supports the ethtool interface for access to the driver171state information, the PHY state and the EEPROM.172