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