cardbus

- configuration files for cardbus device drivers

Description

The CardBus bus share the same configuration parameters with the PCI bus. CardBus devices are self-identifying, which means that these devices provide configuration parameters to the system that allow the system to identify the device and its driver. The configuration parameters are represented in the form of name-value pairs that can be retrieved using the DDI property interfaces. See ddi_prop_lookup(9F) for details.

The CardBus bus properties of CardBus devices are derived from PCI configuration space. Therefore, driver configuration files are not necessary for these devices.

On some occasions, drivers for CardBus devices can use driver configuration files to provide driver private properties through the global property mechanism. See driver.conf(4) for further details. Driver configuration files can also be used to augment or override properties for a specific instance of a driver.

The CardBus nexus driver recognizes the following properties:

reg

An arbitrary length array where each element of the array consists of a 5-tuple of 32-bit values. Each array element describes a logically contiguous mappable resource on the PCI bus.

The first three values in the 5-tuple describe the PCI address of the mappable resource. The first tuple contains the following information:

Bits 0 - 7 8-bit register number Bits 8 - 10 3-bit function number Bits 11 - 15 5-bit device number Bits 16 - 23 8-bit bus number Bits 24 - 25 2-bit address space type identifier Bits 31 – 28 Register number extended bits 8:11 for extended config space. Zero for conventional configuration space.

The address space type identifier can be interpreted as follows:

0x0 configuration space 0x1 I/O space 0x2 32-bit memory space address

The bus number is a unique identifying number assigned to each bus within the PCI or PCIe domain.

The device number is a unique identifying number assigned to each device on a PCI bus, PCIe logical bus, or CardBus bus. A device number is unique only within the set of device numbers for a particular bus or logical bus.

Each CardBus device can have one to eight logically independent functions, each with its own independent set of configuration registers. Each function on a device is assigned a function number. For a device with only one function, the function number must be 0.

The register number fields select a particular register within the set of configuration registers corresponding to the selected function. When the address space type identifier indicates configuration space, non-zero register number extended bits select registers in extended configuration space.

The second and third values in the reg property 5-tuple specify the 64-bit address of the mappable resource within the PCI or PCIe address domain. Since the CardBus is a 32–bit bus, the second 32-bit tuple is not used. The third 32-bit tuple corresponds to the 32–bit address.

The fourth and fifth 32-bit values in the 5-tuple reg property specify the size of the mappable resource. The size is a 64-bit value. Since it's a 32–bit bus, only the fifth tuple is used.

The driver can refer to the elements of this array by index, and construct kernel mappings to these addresses using ddi_regs_map_setup(9F). The index into the array is passed as the rnumber argument of ddi_regs_map_setup(9F).

At a high-level interrupt context, you can use the ddi_get* and ddi_put* family of functions to access I/O and memory space. However, access to configuration space is not allowed when running at a high-interrupt level.

interrupts

This property consists of a single-integer element array. Valid interrupt property values are 1, 2, 3, and 4. This value is derived directly from the contents of the device's configuration-interrupt-pin register.

A driver should use an index value of 0 when registering its interrupt handler with the DDI interrupt interfaces.

All CardBus devices support the reg property. The device number and function number as derived from the reg property are used to construct the address part of the device name under /devices.

Only devices that generate interrupts support an interrupts property.

Occasionally it might be necessary to override or augment the configuration information supplied by a CardBus device. This change can be achieved by writing a driver configuration file that describes a prototype device node specification containing the additional properties required.

For the system to merge the prototype node specification into an actual device node, certain conditions must be met.

• First, the name property must be identical. The value of the name property needs to match the binding name of the device. The binding name is the name chosen by the system to bind a driver to a device and is either an alias associated with the driver or the hardware node name of the device.

• Second, the parent property must identify the PCI bus or PCIe logical bus.

• Third, the unit-address property must identify the card. The format of the unit-address property is:

DD[,F]

where DD is the device number and F is the function number. If the function number is 0, only DD is specified.

Examples

Example 1 Sample Configuration File

An example configuration file called ACME,scsi-hba.conf for a CardBus device driver called ACME,scsi-hba follows:

#
# Copyright (c) 1995, ACME SCSI Host Bus Adaptor
# ident   "@(#)ACME,scsi-hba.conf  1.1  96/02/04"
name="ACME,scsi-hba" parent="/pci@1,0/pci@1f,4000"
   unit-address="3" scsi-initiator-id=6;
hba-advanced-mode="on";
hba-dma-speed=10;

In this example, a property scsi-initiator-id specifies the SCSI bus initiator id that the adapter should use, for just one particular instance of adapter installed in the machine. The name property identifies the driver and the parent property to identify the particular bus the card is plugged into. This example uses the parent's full path name to identify the bus. The unit-address property identifies the card itself, with device number of 3 and function number of 0.

Two global driver properties are also created: hba-advanced-mode (which has the string value on) and hba-dma-speed (which has the value 10 M bit/s). These properties apply to all device nodes of the ACME,scsi-hba.

Attributes

See attributes(5) for descriptions of the following attributes:

See Also

driver.conf(4), attributes(5), ddi_intr_add_handler(9F), ddi_prop_lookup(9F), ddi_regs_map_setup(9F)

Writing Device Drivers

IEEE 1275 PCI Bus Binding