1.. SPDX-License-Identifier: GPL-2.0 2 3===================== 4DM9000 Network driver 5===================== 6 7Copyright 2008 Simtec Electronics, 8 9 Ben Dooks <ben@simtec.co.uk> <ben-linux@fluff.org> 10 11 12Introduction 13------------ 14 15This file describes how to use the DM9000 platform-device based network driver 16that 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 chip 19supported as well as the newer DM9000A and DM9000B devices. It is currently 20maintained and tested by Ben Dooks, who should be CC: to any patches for this 21driver. 22 23 24Defining the platform device 25---------------------------- 26 27The minimum set of resources attached to the platform device are as follows: 28 29 1) The physical address of the address register 30 2) The physical address of the data register 31 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 the 34two address regions is important (the driver expects these to be address 35and then data). 36 37An example from arch/arm/mach-s3c2410/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 from 66the flags field will be passed to request_irq() when registering the IRQ 67handler to ensure that the IRQ is setup correctly. 68 69This shows a typical platform device, without the optional configuration 70platform data supplied. The next example uses the same resources, but adds 71the 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 data 91------------- 92 93Extra platform data for the DM9000 can describe the IO bus width to the 94device, whether or not an external PHY is attached to the device and 95the availability of an external configuration EEPROM. 96 97The flags for the platform data .flags field are as follows: 98 99DM9000_PLATF_8BITONLY 100 101 The IO should be done with 8bit operations. 102 103DM9000_PLATF_16BITONLY 104 105 The IO should be done with 16bit operations. 106 107DM9000_PLATF_32BITONLY 108 109 The IO should be done with 32bit operations. 110 111DM9000_PLATF_EXT_PHY 112 113 The chip is connected to an external PHY. 114 115DM9000_PLATF_NO_EEPROM 116 117 This can be used to signify that the board does not have an 118 EEPROM, or that the EEPROM should be hidden from the user. 119 120DM9000_PLATF_SIMPLE_PHY 121 122 Switch to using the simpler PHY polling method which does not 123 try and read the MII PHY state regularly. This is only available 124 when using the internal PHY. See the section on link state polling 125 for more information. 126 127 The config symbol DM9000_FORCE_SIMPLE_PHY_POLL, Kconfig entry 128 "Force simple NSR based PHY polling" allows this flag to be 129 forced on at build time. 130 131 132PHY Link state polling 133---------------------- 134 135The driver keeps track of the link state and informs the network core 136about link (carrier) availability. This is managed by several methods 137depending on the version of the chip and on which PHY is being used. 138 139For the internal PHY, the original (and currently default) method is 140to read the MII state, either when the status changes if we have the 141necessary interrupt support in the chip or every two seconds via a 142periodic timer. 143 144To reduce the overhead for the internal PHY, there is now the option 145of using the DM9000_FORCE_SIMPLE_PHY_POLL config, or DM9000_PLATF_SIMPLE_PHY 146platform data option to read the summary information without the 147expensive MII accesses. This method is faster, but does not print 148as much information. 149 150When using an external PHY, the driver currently has to poll the MII 151link status as there is no method for getting an interrupt on link change. 152 153 154DM9000A / DM9000B 155----------------- 156 157These chips are functionally similar to the DM9000E and are supported easily 158by the same driver. The features are: 159 160 1) Interrupt on internal PHY state change. This means that the periodic 161 polling of the PHY status may be disabled on these devices when using 162 the internal PHY. 163 164 2) TCP/UDP checksum offloading, which the driver does not currently support. 165 166 167ethtool 168------- 169 170The driver supports the ethtool interface for access to the driver 171state information, the PHY state and the EEPROM. 172