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diff --git a/c-user/config/libpci.rst b/c-user/config/libpci.rst new file mode 100644 index 0000000..b62a56c --- /dev/null +++ b/c-user/config/libpci.rst @@ -0,0 +1,55 @@ +.. SPDX-License-Identifier: CC-BY-SA-4.0 + +.. Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR) + +PCI Library Configuration +========================= + +This section defines the system configuration parameters supported by +``rtems/confdefs.h`` related to configuring the PCI Library for RTEMS. + +The PCI Library startup behaviour can be configured in four different ways +depending on how ``CONFIGURE_PCI_CONFIG_LIB`` is defined: + +.. index:: PCI_LIB_AUTO + +``PCI_LIB_AUTO`` + Used to enable the PCI auto configuration software. PCI will be automatically + probed, PCI buses enumerated, all devices and bridges will be initialized + using Plug & Play software routines. The PCI device tree will be populated + based on the PCI devices found in the system, PCI devices will be configured + by allocating address region resources automatically in PCI space according + to the BSP or host bridge driver set up. + +.. index:: PCI_LIB_READ + +``PCI_LIB_READ`` + Used to enable the PCI read configuration software. The current PCI + configuration is read to create the RAM representation (the PCI device tree) + of the PCI devices present. PCI devices are assumed to already have been + initialized and PCI buses enumerated, it is therefore required that a BIOS or + a boot loader has set up configuration space prior to booting into RTEMS. + +.. index:: PCI_LIB_STATIC + +``PCI_LIB_STATIC`` + Used to enable the PCI static configuration software. The user provides a PCI + tree with information how all PCI devices are to be configured at compile + time by linking in a custom ``struct pci_bus pci_hb`` tree. The static PCI + library will not probe PCI for devices, instead it will assume that all + devices defined by the user are present, it will enumerate the PCI buses and + configure all PCI devices in static configuration accordingly. Since probe + and allocation software is not needed the startup is faster, has smaller + footprint and does not require dynamic memory allocation. + +.. index:: PCI_LIB_PERIPHERAL + +``PCI_LIB_PERIPHERAL`` + Used to enable the PCI peripheral configuration. It is similar to + ``PCI_LIB_STATIC``, but it will never write the configuration to the PCI + devices since PCI peripherals are not allowed to access PCI configuration + space. + +Note that selecting ``PCI_LIB_STATIC`` or ``PCI_LIB_PERIPHERAL`` but not +defining ``pci_hb`` will reuslt in link errors. Note also that in these modes +Plug & Play is not performed. |