BSP Developer's Guide

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Hardware Guidelines
0x10000, /* 64 Kbytes */
VM_STATE_MASK_VALID | VM_STATE_MASK_WRITABLE |
VM_STATE_MASK_CACHEABLE,
VM_STATE_VALID | VM_STATE_WRITABLE | VM_STATE_CACHEABLE_NOT
}
};
int sysPhysMemDescNumEnt = NELEMENTS (sysPhysMemDesc);
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4.5.2 Changes to config.h
Define INCLUDE_MMU_BASIC to enable basic virtual memory support.
4.5.3 Additional Requirements for SPARC Targets
In SPARC BSPs, two global variables in sysLib.c, sysCacheLibInit and
sysMmuLibInit, are used to select appropriate cache and MMU libraries. The
following code segment illustrates this mechanism (Sun-4 MMU example):
/* Sun-4 cache library */
IMPORT mmuSun4LibInit();
FUNCPTR sysCacheLibInit = (FUNCPTR) cacheSun4LibInit;
FUNCPTR sysMmuLibInit = (FUNCPTR) mmuSun4LibInit;
Sun-4 MMU
The Sun-4 MMU page size is typically 8 KB, matching the definition of
VM_PAGE_SIZE in target/config/all/configAll.h. Some hardware implementations
use a different page size. For such a target, override the VM_PAGE_SIZE default
value by adding the following #undef/#define sequence to
config/bspname/config.h (this example assumes a 4 KB page size):
#undef VM_PAGE_SIZE
#define VM_PAGE_SIZE 4096
The Sun-4 MMU supports only eight virtual memory contexts. Additionally, only
66 MB of virtual address space may be mapped at any one time (shared among the
various contexts) because of the finite size of the static RAM containing the
translation tables.
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