PCMCIA

/etc/pcmcia/config - PCMCIA card configuration database

The PCMCIA card configuration file is read by cardmgr(8) at startup time. It defines what resources are available for use by Card Services, describes how to load and initialize device drivers, and describes specific PCMCIA cards.

There are three kinds of resource entries: include, exclude, and reserve. Including a resource enables Card Services to allocate that resource for client drivers. Part of a resource that is under Card Services control can be excluded if a specific device in the system uses that resource. And, a resource can be reserved, so that it will only be assigned to a client if that client specifically asks for that resource, or no other suitable resources are available.

There are three resource types: port, memory, and irq. By default, Card Services assumes that it can use any interrupt that is not bound by another device driver. However, it makes no assumptions about IO port and address ranges, because some Linux drivers do not register their resource usage. So, port and memory ranges must be explicitly made available for use by PCMCIA devices.

So, here is a portion of a config file:

include port 0x300-0x3ff, memory 0xd0000-0xdffff
reserve irq 3
exclude irq 4, port 0x3f8-0x3ff

This says that Card Services can allocate ports in the range 0x300 to 0x3ff, and memory in the range 0xd0000 to 0xdffff. It should not use irq 4 or ports 0x3f8-0x3ff (even if they seem to be available). And irq 3 should only be allocated if a client specifically asks for it.

Card Services will never allocate resources already allocated by another kernel device driver. The include/exclude/reserve mechanism just provides a way of controlling what resources it will try to use, to accomodate devices that are not registered with the Linux resource manager.

All Card Services client drivers are identified by a 32-character tag. Device entries in the config file describe client drivers. The only required field is the device tag. Additional fields can specify kernel modules that need to be loaded to make the device available, and a script to be executed to enable and disable instances of a device. When an instance of a driver is assigned to a socket, it gives cardmgr a device name by which this device will be known by the system (for example, eth0 for a net device, or cua1 for a modem). This name will be passed to the configuration script. For example:

device "pcnet_cs"
  class "network"
  module "net/8390" opts "ei_debug=4", "pcnet_cs"

This says that the pcnet_cs device requires two loadable modules. The first one is located in the net module subdirectory and will be loaded with a specific parameter setting. The second module should be in the pcmcia module subdirectory. The device is in the network class, so the network script in the configuration directory will be used to start or stop the device.

It is also possible to specify default options for a particular kernel module, outside of a device driver declaration. This is convenient for keeping local configuration options in a file separate from the main card configuration file. For example:

module "pcnet_cs" opts "mem_speed=600"

Card declarations map PCMCIA cards to their client drivers. A card declaration consists of a descriptive name, a method for identifying the card when it is inserted, and driver bindings. There are six identification methods: the version method matches a card using its VERSION_1 id strings, the manfid method matches a card using its MANFID tuple codes, the pci method matches a CardBus card using its PCI device ID's, the tuple method matches a card using any string embedded in any arbitrary CIS tuple, the function method matches a card using its function ID, and the anonymous method matches any card that does not have a CIS. This last method is only intended to be used for old-style Type I memory cards. For example:

card "Linksys Ethernet Card"
  tuple 0x40, 0x0009, "E-CARD PC Ethernet Card"
  bind "pcnet_cs"

This card is identified by a string at offset 0x0009 in tuple 0x40, and will be bound to the pcnet_cs driver (which must be already declared in a driver declaration).

card "Connectware LANdingGear Adapter"
  manfid 0x0057, 0x1004
  bind "pcnet_cs"

This card is identified by its MANFID tuple contents. The pci method has the same form, with pci replacing manfid.

card "D-Link DE-650 Ethernet Card"
  version "D-Link", "DE-650"
  bind "pcnet_cs"

This card will be identified using its VERSION_1 tuple, and will also be bound to the pcnet_cs driver.

card "Serial port device"
  function serial_port
  bind "serial_cs"

This binds the serial_cs driver to any card with a CIS function ID of 0x02, which corresponds to a serial port card. The function ID can either be a number, or one of the following predefined functions: memory_card, serial_port, parallel_port, fixed_disk, video_adapter, network_adapter, and aims_card.

Finally, the configuration file can specify that Card Services should use a replacement for the configuration information found on a card. This can be useful if a card's configuration information is particularly incomplete or inaccurate. The new information is read from a file as in this example:

card "Evil broken card"
  manfid 0x1234, 0x5678
  cis "fixup.cis"
  bind "serial_cs"

Memory region definitions are used to associate a particular type of memory device with a Memory Technology Driver, or "MTD". An MTD is used to service memory accesses in a device-independent fashion. When a card is identified, Card Services will attempt to load MTD's for all its memory regions.

A memory region definition begins with the region keyword and a descriptive string. This is followed by an identification method: either default to identify an MTD to be used for any otherwise unclassified region, or jedec to identify a region based on its JEDEC identification codes. Thus, for example,

region "Intel Series 2 Flash"
  jedec 0x89 0xa2
  mtd "iflash2_mtd"

specifies that the iflash2_mtd driver will be loaded based on a JEDEC match.

The reserve keyword has not actually been implemented in a useful way for this version of Card Services.

David Hinds - dahinds@users.sourceforge.net

cardmgr(8).