S3C2440之MMU驱动代码模板(RealView MDK)

好记心不如烂笔头,为方便以后查看代码及代码重复利用,这里贴出自己写的S3C2440 MMU代码库。使用友善MINI2440开发板,开发环境为RealView MDK 4.22。

该源码结构简单明了,原始工程下载地址:点击打开链接


Register 0, ID code register:

unsigned int MMU_ReadID(void)
{
	unsigned int id;
	__asm("mrc p15, 0, id, c0, c0, 0");
	return id;
}

Register 0, cache type register:

unsigned int MMU_ReadCacheType(void)
{
	unsigned int type;
	__asm("mrc p15, 0, type, c0, c0, 1");
	return type;
}

Register 1, control register:

void MMU_EnterFastBusMode(void)
{
	unsigned int r0;
	__asm{
		mrc p15, 0, r0, c1, c0, 0
		bic r0, r0, #(3<<30)
		mcr p15, 0, r0, c1, c0, 0
	}
}

void MMU_EnterSyncMode(void)
{
	unsigned int r0;
	__asm{
		mrc p15, 0, r0, c1, c0, 0
		bic r0, r0, #(1<<31)
		orr r0, r0, #(1<<30)
		mcr p15, 0, r0, c1, c0, 0
	}
}

void MMU_EnterAsyncMode(void)
{
	unsigned int r0;
	__asm{
		mrc p15, 0, r0, c1, c0, 0
		orr r0, r0, #(11<<30)
		mcr p15, 0, r0, c1, c0, 0
	}
}


void MMU_EnableICache(void)
{
	unsigned int r0;
	__asm{
		mrc p15, 0, r0, c1, c0, 0
		orr r0, r0, #(1<<12)
		mcr p15, 0, r0, c1, c0, 0
	}
}


void MMU_DisableICache(void)
{
	unsigned int r0;
	__asm{
		mrc p15, 0, r0, c1, c0, 0
		bic r0, r0, #(1<<12)
		mcr p15, 0, r0, c1, c0, 0
	}
}


void MMU_EnableDCache(void)
{
	unsigned int r0;
	__asm{
		mrc p15, 0, r0, c1, c0, 0
		orr r0, r0, #(1<<2)
		mcr p15, 0, r0, c1, c0, 0
	}
}


void MMU_DisableDCache(void)
{
	unsigned int r0;
	__asm{
		mrc p15, 0, r0, c1, c0, 0
		bic r0, r0, #(1<<2)
		mcr p15, 0, r0, c1, c0, 0
	}
}

void MMU_EnableAlignFault(void)
{
	unsigned int r0;
	__asm{
		mrc p15, 0, r0, c1, c0, 0
		orr r0, r0, #(1<<1)
		mcr p15, 0, r0, c1, c0, 0
	}
}


void MMU_DisableAlignFault(void)
{
	unsigned int r0;
	__asm{
		mrc p15, 0, r0, c1, c0, 0
		bic r0, r0, #(1<<1)
		mcr p15, 0, r0, c1, c0, 0
	}
}

void MMU_Enable(void)
{
	unsigned int r0;
	__asm{
		mrc p15, 0, r0, c1, c0, 0
		orr r0, r0, #1
		mcr p15, 0, r0, c1, c0, 0
	}
}


void MMU_Disable(void)
{
	unsigned int r0;
	__asm{
		mrc p15, 0, r0, c1, c0, 0
		bic r0, r0, #1
		mcr p15, 0, r0, c1, c0, 0
	}
}

Register 2, translation table base (TTB) register:

void MMU_SetTTB(void)
{
	unsigned int r0 = (unsigned int)TTB;
	__asm("mcr p15, 0, r0, c2, c0, 0");
}

Register 3, domain access control register:

void MMU_SetDomain(unsigned int domain)
{
	__asm("mcr p15, 0, domain, c3, c0, 0");
}

Register 7, cache operations register:

void MMU_InvalidICacheDCache(void)
{
	unsigned int r0 = 0;
	
	__asm("mcr p15, 0, r0, c7, c7, 0");
}

void MMU_InvalidICache(void)
{
	unsigned int r0 = 0;
	
	__asm("mcr p15, 0, r0, c7, c5, 0");
}

void MMU_InvalidICacheSingleEntry(unsigned int MVA)
{
	__asm("mcr p15, 0, MVA, c7, c5, 1");
}

void MMU_PrefechICacheLine(unsigned int MVA)
{
	__asm("mcr p15, 0, MVA, c7, c13, 1");
}

void MMU_InvalidDCache(void)
{
	unsigned int r0 = 0;
	
	__asm("mcr p15, 0, r0, c7, c6, 0");
}

void MMU_InvalidDCacheSingleEntry(unsigned int MVA)
{
	__asm("mcr p15, 0, MVA, c7, c6, 1");
}

void MMU_CleanDCacheSingleEntry(unsigned int MVA)
{
	__asm("mcr p15, 0, MVA, c7, c10, 1");
}

void MMU_CleanInvalidDCacheEntry(unsigned int MVA)
{
	__asm("mcr p15, 0, MVA, c7, c14, 1");
}

void MMU_CleanDCacheSingleEntry2(unsigned int index)
{
	__asm("mcr p15, 0, index, c7, c10, 2");
}

void MMU_CleanInvalidDCacheEntry2(unsigned int index)
{
	__asm("mcr p15, 0, index, c7, c14, 2");
}

void MMU_DrainWriteBuffer(void)
{
	unsigned int r0 = 0;
	
	__asm("mcr p15, 0, r0, c7, c10, 4");
}

void MMU_WaitForInterrupt(void)
{
	unsigned int r0 = 0;
	
	__asm("mcr p15, 0, r0, c7, c0, 4");
}

Register 8, TLB operations register:

void MMU_InvalidAllTLB(void)
{
	unsigned int r0 = 0;
	
	__asm("mcr p15, 0, r0, c8, c7, 0");
}

void MMU_InvalidITLB(void)
{
	unsigned int r0 = 0;
	
	__asm("mcr p15, 0, r0, c8, c5, 0");
}

void MMU_InvalidITLBSingleEntry(unsigned int MVA)
{
	__asm("mcr p15, 0, MVA, c8, c5, 1");
}

void MMU_InvalidDTLB(void)
{
	unsigned int r0 = 0;
	
	__asm("mcr p15, 0, r0, c8, c6, 0");
}

void MMU_InvalidDTLBSingleEntry(unsigned int MVA)
{
	__asm("mcr p15, 0, MVA, c8, c6, 1");
}

Register 9, cache lockdown register:

unsigned int MMU_ReadDCacheLockdownBase(void)
{
	unsigned int r0;
	
	__asm("mrc p15, 0, r0, c9, c0, 0");
	r0 >>= 26;
	
	return r0;
}

void MMU_WriteDCacheLockdownBase(unsigned int index)
{
	index <<= 26;
	__asm("mcr p15, 0, index, c9, c0, 0");
}


unsigned int MMU_ReadICacheLockdownBase(void)
{
	unsigned int r0;
	
	__asm("mrc p15, 0, r0, c9, c0, 1");
	r0 >>= 26;
	
	return r0;
}

void MMU_WriteICacheLockdownBase(unsigned int index)
{
	index <<= 26;
	__asm("mcr p15, 0, index, c9, c0, 1");
}

Register 13, FCSE PID register:

unsigned int MMU_ReadPID(void)
{
	unsigned int pid;
	
	__asm("mrc p15, 0, pid, c13, c0, 0");
	
	return (pid >> 25);
}

void MMU_WritePID(unsigned int pid)
{
	pid <<= 25;
	__asm("mcr p15, 0, pid, c13, c0, 0");
}

设置Memory Translation Table:

void MMU_SetMTT(unsigned int vStart, unsigned int vEnd, unsigned int pStart, unsigned int attr)
{
	unsigned int vaddr, paddr;
	
	vaddr = vStart;
	paddr = pStart;
	while(vaddr != (vEnd + 1))
	{
		TTB[vaddr >> 20] = (paddr & 0xFFF00000) | attr;
		vaddr += 0x100000;
		paddr += 0x100000;
	}
}

MMU初始化:

void MMU_Init(void)
{
	MMU_DisableICache();
	MMU_DisableDCache();
	
	MMU_SetTTB();
	MMU_SetDomain(0xFFFFFFFF);
	MMU_InvalidAllTLB();
	MMU_EnableAlignFault();
	
	MMU_SetMTT(0x00000000, 0x001FFFFF, 0x00000000, RW_CB);
	MMU_SetMTT(0x30000000, 0x33FFFFFF, 0x30000000, RW_CB);
	MMU_SetMTT(0x40000000, 0x4FFFFFFF, 0x40000000, RW_NCNB);
	MMU_SetMTT(0x50000000, 0x5FFFFFFF, 0x50000000, RW_NCNB);
	
	MMU_EnableICache();
	MMU_EnableDCache();
	MMU_Enable();
}

在本代码中需要注意的是,如果直接使用S3C2440.s的话,在C代码中调用上述代码会导致Undefine异常。因为进入main()之前,启动代码已经将处理器模式设置为USER模式了,而在USER模式下是无法操作CP15处理器的,所以产生异常。如果要在C中正常调用上述嵌入汇编,则需要将启动代码S3C2440.s中处理器模式设置为USER模式的那段代码注释掉,直接以SVC模式运行,就能正常执行,如下:

;  Enter Supervisor Mode and set its Stack Pointer
                MSR     CPSR_c, #Mode_SVC:OR:I_Bit:OR:F_Bit
                MOV     SP, R0
                SUB     R0, R0, #SVC_Stack_Size

;  Enter User Mode and set its Stack Pointer
;                MSR     CPSR_c, #Mode_USR
;                MOV     SP, R0
;                SUB     SL, SP, #USR_Stack_Size

;  Enter User Mode and set its Stack Pointer
;                MSR     CPSR_c, #Mode_USR
;                IF      :DEF:__MICROLIB

;                EXPORT __initial_sp

;                ELSE

;                MOV     SP, R0
;                SUB     SL, SP, #USR_Stack_Size

;                ENDIF

或者不修改处理器模式,而直接将以下汇编插入到S3C2440.s中Clock设置代码的后面,一样能运行:

mrc p15, 0, r0, c1, c0, 0 
orr r0, r0, #0xc0000000 
mcr p15, 0, r0, c1, c0, 0 



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