BSP Developer's Guide

VxWorks 5.5
BSP Developer’s Guide
– Address and length parameters must be multiples of VM_PAGE_SIZE,
defined as 8192 in configAll.h.
– Because each mapped page requires a page table entry to be stored in
physical memory, there is a physical memory size-dependent upper limit
to the amount of address space that can be mapped. Do not map vast
regions of VMEbus space. To be safe, do not map more than 32 MB per
record.
– When virtual memory support is enabled (see below), CPU accesses
falling outside the physical memory description result in bus errors.
Memory mapped devices (Ethernet, SCSI, serial, and others) are not
accessible unless included in the sysPhysMemDesc[ ] array.
■
Add the following at the beginning of sysToMonitor( ):
VM_ENABLE (FALSE); /* disable MMU */
Example 4-1
Additions to sysLib.c for Virtual Memory Support
/* includes */
#include "private/vmLibP.h"
/* globals */
PHYS_MEM_DESC sysPhysMemDesc [] =
{
/* adrs and length parameters must be page-aligned */
/* RAM */
{
(void *) LOCAL_MEM_LOCAL_ADRS,
(void *) LOCAL_MEM_LOCAL_ADRS,
LOCAL_MEM_SIZE,
VM_STATE_MASK_VALID | VM_STATE_MASK_WRITABLE |
VM_STATE_MASK_CACHEABLE,
VM_STATE_VALID | VM_STATE_WRITABLE | VM_STATE_CACHEABLE
},
/* ROM */
{
(void *) ROM_BASE_ADRS,
(void *) ROM_BASE_ADRS,
ROM_SIZE,
VM_STATE_MASK_VALID | VM_STATE_MASK_WRITABLE |
VM_STATE_MASK_CACHEABLE,
VM_STATE_VALID | VM_STATE_WRITABLE_NOT | VM_STATE_CACHEABLE_NOT
}, /* a16 VME */
{
(void *) SHORT_IO_ADRS,
(void *) SHORT_IO_ADRS,
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