GET_SET_DEVICE_DATA callback function (wdm.h)
The GetBusData routine reads data from the device's configuration space.
Syntax
GET_SET_DEVICE_DATA GetSetDeviceData;
ULONG GetSetDeviceData(
[in] PVOID Context,
[in] ULONG DataType,
[in] PVOID Buffer,
[in] ULONG Offset,
[in] ULONG Length
)
{...}
Parameters
[in] Context
A pointer to interface-specific context information. The caller passes the value that is passed as the Context member of the BUS_INTERFACE_STANDARD structure for the interface.
[in] DataType
The type of bus data to read. For more information, see the discussion of the WhichSpace parameter in IRP_MN_READ_CONFIG.
[in] Buffer
A pointer to the buffer that holds the configuration information to be read from the device's configuration space.
[in] Offset
The offset into the bus-specific device data where this read operation begins. For example, if the DataType parameter is PCI_WHICHSPACE_CONFIG, the Offset parameter value is the offset into PCI Configuration Space.
[in] Length
The length, in bytes, of data to read.
Return value
The GetBusData routine returns the length, in bytes, of the configuration data that is read after a successful read operation. If the read operation is unsuccessful, a value of zero is returned.
Remarks
Depending on the value of the DataType parameter, the GetBusData routine can be called only from the interrupt request levels (IRQLs) that are defined in the following table.
| DataType value | IRQL |
|---|---|
| PCI_WHICHSPACE_CONFIG | <= DIRQL |
| PCI_WHICHSPACE_ROM | <= APC_LEVEL |
|
PCCARD_COMMON_MEMORY
PCCARD_COMMON_MEMORY_INDIRECT |
<= DISPATCH_LEVEL |
|
PCCARD_ATTRIBUTE_MEMORY
PCCARD_ATTRIBUTE_MEMORY_INDIRECT |
<= DISPATCH_LEVEL |
| PCCARD_PCI_CONFIGURATION_SPACE | <= DIRQL |
The following remarks apply to drivers for PCI Express (PCIe) virtual functions (VFs) on devices that support the single root I/O virtualization (SR-IOV) interface:
- Drivers for PCIe VFs should call the GetBusData routine at IRQL <= APC_LEVEL.
- In order to read PCI Configuration data for the VF at IRQL = DISPATCH_LEVEL, the driver must issue I/O requests of IRP_MN_READ_CONFIG.
Requirements
| Requirement | Value |
|---|---|
| Target Platform | Desktop |
| Header | wdm.h (include Ntddk.h) |
| IRQL | See Remarks section. |