DDI_REGS_MAP_SETUP(9F) Kernel Functions for Drivers DDI_REGS_MAP_SETUP(9F)

ddi_regs_map_setup - set up a mapping for a register address space

#include <sys/ddi.h>
#include <sys/sunddi.h>
int ddi_regs_map_setup(dev_info_t *dip, uint_t rnumber, caddr_t *addrp,
     offset_t offset, offset_t len, ddi_device_acc_attr_t *accattrp,
     ddi_acc_handle_t *handlep);

illumos DDI specific (illumos DDI).

Pointer to the device's dev_info structure.


Index of the desired tuple (0-based) in the register address space set. See the Register Numbers section for more information.


A platform-dependent value that, when added to an offset that is less than or equal to the len parameter (see below), is used for the dev_addr argument to the ddi_get, ddi_mem_get, and ddi_io_get/put routines.


Offset into the register address space.


Length to be mapped.


Pointer to a device access attribute structure of this mapping (see ddi_device_acc_attr(9S)).


Pointer to a data access handle.

ddi_regs_map_setup() maps in the register set given by rnumber. The register number determines which register set is mapped if more than one exists.

offset specifies the starting location within the register space and len indicates the size of the area to be mapped. If len is non-zero, it overrides the length given in the register set description. If both len and offset are 0, the entire space is mapped. The base of the mapped register space is returned in addrp.

The device access attributes are specified in the location pointed by the accattrp argument (see ddi_device_acc_attr(9S) for details).

The data access handle is returned in handlep. handlep is opaque; drivers should not attempt to interpret its value. The handle is used by the system to encode information for subsequent data access function calls to maintain a consistent view between the host and the device.

The reg property is an array of tuples. The size of each tuple varies based on the hardware device type. For example, PCI and PCI Express devices have one size, while ISA devices have a different size. Each tuple describes a register space that indicates a way to communicate with the device. The rnumber argument selects which of these to use.

For example, with PCI and PCI Express devices, the first base address register (BAR) with a non-zero value is in rnumber 1 because it is the second tuple in the reg property. The second BAR with a non-zero value is in the third tuple (rnumber 2).

For a full treatment of the meaning of the reg property for PCI devices, see pci(4). For PCI express devices, see pcie(4). For ISA devices, see isa(4). For cardbus, see cardbus(4). For SBus devices, see sbus(4).

ddi_regs_map_setup() returns:


Successfully set up the mapping for data access.


Invalid register number rnumber, offset offset, or length len.


Invalid register number rnumber or unable to find reg property.


Cannot enable the register mapping due to access conflicts with other enabled mappings.

Note that the return value DDI_ME_RNUMBER_RANGE is not supported on all platforms. Also, there is potential overlap between DDI_ME_RNUMBER_RANGE and DDI_FAILURE. Drivers should check for !=DDI_SUCCESS rather than checking for a specific failure value.

ddi_regs_map_setup() must be called from user or kernel context.

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

Architecture PCI Local Bus, SBus, ISA

cardbus(4), isa(4), pci(4), pcie(4), sbus(4), attributes(5), ddi_regs_map_free(9F), ddi_device_acc_attr(9S)

Writing Device Drivers

April 18, 2019 OmniOS