Activating a device These should not generally be used by any code other than the PCI library, and are present in the HAL to allow low level initialization of the PCI bus and devices to take place if necessary. The above functions only allow access to generic PCI config registers. This only needs to be done once – some HALs may do it as part of the platform initialization procedure, other HALs may leave it to the application or device drivers to do it. The pci1 test prints out some of this information:. In that case drivers will have to access PCI memory space in segments. What happens is that the bus gets initialized and a scan is started.

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This is provided by two APIs. This is comprised of the bus number, device number and functional unit numbers packed into a single word. Activating a device Scanning for devices When a valid device ID devid is found using one of the above functions, the associated device can be queried rcos controlled using the functions:. Allocate memory and IO space to pxi base address registers on all devices on the given bus and all subordinate busses.

Re: PCI Address Mapping

These functions allow a device driver to set up its own mappings if it wants. If successful, true is returned. Normally these base addresses will be set to default values based on the platform. This macro, if defined, may be used to limit which BARs are discovered and configured. When the device has been allocated memory space it can be activated.


The devid will be updated with the ID of the next device found. After the bus has been initialized, it is possible to scan it for devices.

Chapter The eCos PCI Library

Generic config information The low level API is used by the PCI library itself to access the hardware in a platform-specific manner, and may also be used by device drivers to access the PCI configuration space directly. These routines allow eccos to be changed by application code if necessary.

Otherwise, false is returned. The following code fragment demonstrates how these macros may be used:. It should not be necessary to use these macros under normal circumstances.

Michael Kelly – Re: PCI Address Mapping

Searches the PCI bus configuration space for a device with the given vendor and device ids. This function sets the PCI configuration information for the device indicated in devid. All PCI devices have a unique address in configuration space. The PCI support library provides a set of routines for accessing the PCI bus configuration space in a portable manner. These macros define offsets to be added to the PCI base addresses to translate Eos bus addresses into physical memory addresses that can be used to access the allocated memory or IO space.


The PCI standard supports up to busses with each bus having up to 32 devices and each device having up to 8 functions.

The command register can also be written to, controlling among other things whether the device responds to IO and memory edos from the bus. Initializing the bus The pci1 test prints out some of this information:. The devid serves as both an input and an output operand: Otherwise the result is false.

Frequently the PCI address spaces are windowed into the processor’s address range at some offset. If the platform acts as a host on a single Fcos bus, then devices may be configured individually from the relevant device driver. In that case drivers will have to access PCI memory space in segments. Specific config information Before devices on the bus can be used, they must be configured.

The above functions only allow access to generic PCI pc registers.