地址映射-Vx5&6

Taishan3721

发布于 2023-11-09 15:35:43

1850

发布于 2023-11-09 15:35:43

文章被收录于专栏：这里只有VxWorks

可能有个误区：VxWorks可以直接访问Memory的物理地址。个人愚见：程序使用的就叫虚拟地址，只不过Vx5和Vx6里虚拟地址与物理地址的值通常相等

用相应的Show命令看一下地址转换表

为什么是这样的？在Vx5和Vx6的BSP里都会有个sysLib.c文件，里面都会有一个全局数组sysPhysMemDesc，看一下它的值

就是这个表来映射地址的，虚拟地址和物理地址使用的都是同一个值

扒一下它在Vx55的加载顺序

void usrRoot(char *pMemPoolStart, unsigned memPoolSize)
{
    ...
    usrMmuInit();
    ...
    }

void usrMmuInit()
{
    ...
    if((vmLibInit(VM_PAGE_SIZE) != OK) ||
       (vmGlobalMapInit(&sysPhysMemDesc[0], sysPhysMemDescNumEnt, TRUE) == NULL))
        ...
    ...
    return;
    }

VM_CONTEXT_ID vmGlobalMapInit(PHYS_MEM_DESC *pMemDescArray, int numDescArrayElements, BOOL enable)
{
    int i;
    PHYS_MEM_DESC *thisDesc;
    for (i = 0; i < numDescArrayElements; i++)
        {
        thisDesc = &pMemDescArray[i];

        /* map physical directly to virtual and set initial state */
        if (vmGlobalMap ((void *)thisDesc->virtualAddr, 
            (void *)thisDesc->physicalAddr, thisDesc->len) == ERROR)
            {
            ...
            }
        }
    ...
    }

#define MMU_GLOBAL_PAGE_MAP (*(mmuLibFuncs.mmuGlobalPageMap))
STATUS vmGlobalMap(void *virtualAddr, void *physicalAddr, UINT len)
{
    char *thisVirtPage = (char *)virtualAddr;
    char *thisPhysPage = (char *)physicalAddr;
        if(MMU_GLOBAL_PAGE_MAP (thisVirtPage, thisPhysPage) == ERROR)
        {
        ...
        }
    ...
    }

Vx69的大同小异

void usrRoot(char *pMemPoolStart, unsigned memPoolSize)
{
    ...
    usrMmuInit((VIRT_ADDR)pMemPoolStart, memPoolSize); /* MMU global map support */
    ...
    }

#define MEM_DESC          sysPhysMemDesc
#define MEM_DESC_NUM_ENT sysPhysMemDescNumEnt
void usrMmuInit(VIRT_ADDR memPoolStartAdrs, unsigned memPoolSize)
{
    ...
    if(vmGlobalMapInit(MEM_DESC, MEM_DESC_NUM_ENT, TRUE, MMU_DEFAULT_CACHE_MODE) == NULL)
        ...
    ...
    }
#define MMU_GLOBAL_PAGE_MAP (*(mmuLibFuncs.mmuGlobalPageMap))
VM_CONTEXT_ID vmGlobalMapInit(PHYS_MEM_DESC * pMemDescArray, int numDescArrayElements, BOOL enable, UINT cacheDefault)
{
    ...                                                                                                                          
    MMU_GLOBAL_PAGE_MAP(thisDesc->virtualAddr, thisDesc->physicalAddr,...);
    ...
    }

如果物理地址很难静态指定呢？例如PCI或USB设备。那就使用sysMmuMapAdd()

从源码至少可以得到两个信息

虚拟地址与物理地址的值相等
数组的长度要足够

扒一下Vx55下Intel PRO1000网卡驱动的地址映射过程

void usrInit(int startType)
    {
    ...
    sysHwInit();
    ...
    }

void sysHwInit()
    {
    ...
    /* initialize PCI network controllers starting from Bus 0 */
     pciConfigForeachFunc(0, TRUE, (PCI_FOREACH_FUNC)sysNetPciInit, NULL);
    ...
    }

VEND_ID_DESC vendorIdEnet[] =
    {
    ...
#if defined(INCLUDE_GEI8254X_END)
    {INTEL_PCI_VENDOR_ID, sys543PciInit},
#endif
    {0xffffffff, NULL}        /* last entry */
    };
STATUS sysNetPciInit(UINT32 pciBus, UINT32 pciDevice, UINT32 pciFunc, void *pArg)
    {
    ...
    /* find & exec. a PCI initialization routine for the device */
    for(i = 0; (vendorIdEnet[i].pPciInitRtn) != NULL; ++i)
        {
        if((vendorId == vendorIdEnet[i].vendorId) && 
            (*(vendorIdEnet[i].pPciInitRtn))(...) == OK)
            {
            /* initialized the device - move on */
            return OK;
            }
        }
    ...
    }

STATUS sys543PciInit(...)
    {
    ...
    /* map the memory-mapped IO (CSR) space into host CPU address space */
    if(sysMmuMapAdd(...) == ERROR)
        {
        ...
        }
    ...
    }

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原始发表：2023-11-07，如有侵权请联系 cloudcommunity@tencent.com 删除

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