OEMAddressTable 内存映射表是怎么被wince使用的

1. ;------------------------------------------------------------------------------
2. ;
3. ;  File:  memory_cfg.inc
4. ;
5. ;  This file is used to define g_oalAddressTable. This table is passed to
6. ;  KernelStart to estabilish physical to virtual memory mapping. This table
7. ;  is used also in IOMEM OAL module to map between physical and virtual
8. ;  memory addresses via OALPAtoVA/OALVAtoPA functions.
9. ;
10. ;------------------------------------------------------------------------------
12. ; Export Definition
14.         EXPORT  g_oalAddressTable[DATA]
16. ;------------------------------------------------------------------------------
17. ;
18. ; TABLE FORMAT
19. ;       cached address, physical address, size
20. ;------------------------------------------------------------------------------
22. g_oalAddressTable
24.         DCD     0x80000000, 0x30000000, 64      ; 32 MB DRAM BANK 6
25.         DCD     0x84000000, 0x10000000, 32      ; nGCS2: PCMCIA/PCCARD
26.         DCD     0x86000000, 0x18000000, 32      ; 32 MB SROM(SRAM/ROM) BANK 3
27.         DCD     0x88000000, 0x20000000, 32      ; 32 MB SROM(SRAM/ROM) BANK 4
28.         DCD     0x8A000000, 0x28000000, 32      ; 32 MB SROM(SRAM/ROM) BANK 5
29.         DCD     0x8C000000, 0x08000000, 32      ; 32 MB SROM(SRAM/ROM) BANK 1
30.         DCD     0x90800000, 0x48000000,  1      ; Memory control register
31.         DCD     0x90900000, 0x49000000,  1      ; USB Host register
32.         DCD     0x90A00000, 0x4A000000,  1      ; Interrupt Control register
33.         DCD     0x90B00000, 0x4B000000,  1      ; DMA control register
34.         DCD     0x90C00000, 0x4C000000,  1      ; Clock & Power register
35.         DCD     0x90D00000, 0x4D000000,  1      ; LCD control register
36.         DCD     0x90E00000, 0x4E000000,  1      ; NAND flash control register
37.         DCD     0x90F00000, 0x4F000000,  1      ; Camera control register
38.         DCD     0x91000000, 0x50000000,  1      ; UART control register
39.         DCD     0x91100000, 0x51000000,  1      ; PWM timer register
40.         DCD     0x91200000, 0x52000000,  1      ; USB device register
41.         DCD     0x91300000, 0x53000000,  1      ; Watchdog Timer register
42.         DCD     0x91400000, 0x54000000,  1      ; IIC control register
43.         DCD     0x91500000, 0x55000000,  1      ; IIS control register
44.         DCD     0x91600000, 0x56000000,  1      ; I/O Port register
45.         DCD     0x91700000, 0x57000000,  1      ; RTC control register
46.         DCD     0x91800000, 0x58000000,  1      ; A/D convert register
47.         DCD     0x91900000, 0x59000000,  1      ; SPI register
48.         DCD     0x91A00000, 0x5A000000,  1      ; SD Interface register
49.         DCD     0x92000000, 0x00000000, 32      ; 32 MB SROM(SRAM/ROM) BANK 0
50.         DCD     0x00000000, 0x00000000,  0      ; end of table
52. ;------------------------------------------------------------------------------
54.         END

以前，一直不知道这个表是怎么回事，刚才偶然的机会，看见了调用他的函数

C:\WINCE500\PLATFORM\COMMON\SRC\ARM\COMMON\MEMORY\memory.c

2. //------------------------------------------------------------------------------
3. //
4. //  File:  memory.c
5. //  从这个代码看出ARM虚拟内存和物理内存的关系
6. //  Memory interface routines.
7. //
8. #include <windows.h>
9. #include <oal_log.h>
10. #include <oal_memory.h>
12. typedef struct {
13.     UINT32  CA;                         // cached virtual address
14.     UINT32  PA;                         // physical address
15.     UINT32  size;                       // size, in MB bytes
16. } OAL_ADDRESS_TABLE, *POAL_ADDRESS_TABLE;
18. //------------------------------------------------------------------------------
21. //------------------------------------------------------------------------------
22. //
23. //  Function:  OALPAtoVA
24. //
25. //  Converts a physical address (PA) to a virtual address (VA). This routine
26. //  uses the OEMAddressTable defined in the platform.
27. //
28. VOID* OALPAtoVA(UINT32 pa, BOOL cached)
29. {
30.     OAL_ADDRESS_TABLE *pTable = g_oalAddressTable;
31.     VOID *va = NULL;
33.     OALMSG(OAL_MEMORY&&OAL_FUNC, (L"+OALPAtoVA(0x%x, %d)\r\n", pa, cached));
35. // Search the table for address range
36. while (pTable->size != 0) {
37. if (
38.             pa >= pTable->PA &&
39.             pa <= (pTable->PA + (pTable->size << 20) - 1)
40.         ) break;            // match found 找到表中相近的内存
41.         pTable++;
42.     }
44. // If address table entry is valid compute the VA
45. if (pTable->size != 0) {
46.         va = (VOID *)(pTable->CA + (pa - pTable->PA));
47. // If VA is uncached, set the uncached bit
48. if (!cached) (UINT32)va |= OAL_MEMORY_CACHE_BIT;
49.     }
51. // Indicate the virtual address
52.     OALMSG(OAL_MEMORY&&OAL_FUNC, (L"-OALPAtoVA(va = 0x%08x)\r\n", va));
53. return va;
54. }
57. //------------------------------------------------------------------------------
58. //
59. //  Function:  OALVAtoPA
60. //
61. //  Converts a virtual address (VA) to a physical address (PA). This routine
62. //  uses the OEMAddressTable defined in the platform.
63. //
64. UINT32 OALVAtoPA(VOID *pVA)
65. {
66.     OAL_ADDRESS_TABLE *pTable = g_oalAddressTable;
67.     UINT32 va = (UINT32)pVA;
68.     UINT32 pa = 0;
70.     OALMSG(OAL_MEMORY&&OAL_FUNC, (L"+OALVAtoPA(0x%08x)\r\n", pVA));
72. // Virtual address must be in CACHED or UNCACHED regions.虚拟内存范围
73. if (va < 0x80000000 || va >= 0xC0000000) {
74.         OALMSG(OAL_ERROR, (
75.             L"ERROR:OALVAtoPA: invalid virtual address 0x%08x\r\n", pVA
76.         ));
77. goto cleanUp;
78.     }
80. // Address must be cached, as entries in OEMAddressTable are cached address.
81.     va = va&~OAL_MEMORY_CACHE_BIT;
83. // Search the table for address range
84. while (pTable->size != 0) {
85. if (va >= pTable->CA && va <= pTable->CA + (pTable->size << 20) - 1) {
86. break;
87.         }
88.         pTable++;
89.     }
91. // If address table entry is valid compute the PA
92. if (pTable->size != 0) pa = pTable->PA + va - pTable->CA;
94. cleanUp:
95. // Indicate physical address 
96.     OALMSG(OAL_MEMORY&&OAL_FUNC, (L"-OALVAtoPA(pa = 0x%x)\r\n", pa));
97. return pa;
98. }
100. //------------------------------------------------------------------------------
101. //从这两个函数可以看出，这个表只是为了容易修改而已，其实手动访问虚拟内存也是可
102. //的。至于访问GPIO 的那种访问留到有机会再说了。good luck 今天收获不小。

转载请标明:作者wogoyixikexie@gliet.桂林电子科技大学一系科协。如有错误，希望能够留言指出。