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3 Porting a BSP to Custom Hardware

3.3 Finalizing Your BSP

In addition, PCI support requires routines for low-level reads and writes to the PCI

configuration space. These routines are referenced from the PCI configuration files

through macros. The required macros are:

Typically, these macros refer to the following routines:

In addition to the PCI configuration space manipulation, you may also want to

provide routines to access device registers in PCI memory or I/O space, and do

appropriate byte swapping. For example, you may choose to include the following

routines:

The use of such routines makes it easier for variants of the BSP to support both big-

and little-endian configurations.

PCI_IN_BYTE read a byte from PCI I/O space

PCI_IN_WORD read a word from PCI I/O space

PCI_IN_LONG read a longword from PCI I/O space

PCI_OUT_BYTE write a byte from PCI I/O space

PCI_OUT_WORD write a word from PCI I/O space

PCI_OUT_LONG write a longword from PCI I/O space

sysPciInByte( ) reads a byte from PCI configuration space

sysPciInWord( ) reads a word (16-bit) from PCI configuration space

sysPciInLong( ) reads a long (32-bit) from PCI configuration space

sysPciOutByte( ) writes a byte to PCI configuration space

sysPciOutWord( ) writes a word (16-bit) to PCI configuration space

sysPciOutLong( ) writes a long (32-bit) to PCI configuration space

NOTE: Each of these routines returns the data in the same format used by the

processor. Because PCI is defined as little-endian, BSPs for processors that are big

endian must do byte-swapping in these sysPci*() routines.

sysPciRead32( ) read 32-bit PCI (I/O or memory) data

sysPciWrite32( ) write a 32-bit data item to PCI space

sysPciRead16( ) read 16-bit PCI (I/O or memory) data

sysPciWrite16( ) write a 16-bit data item to PCI space

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RAM 6.0 BUX II Series Guía de usuario Pagina 87