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mmap in kernel module

Hi, i'm newby in kernel programming.

I need to directly address a device in the memory, but i can't use open, mmap and munmap.

What i actually need to do is the following (from application point of view): """ mem = open("/dev/mem", O_RDWR | O_SYNC); base = mmap(0, MAP_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, mem, EBI_BASE & ~MAP_MASK); munmap(base, MAP_SIZE); cs_base = mmap(0, MAP_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, mem, CS_BASE & ~MAP_MASK); """ MAP_SIZE, MAP_SHARED, CS_BASE, EBI_BASE and MAP_MASK are predifinied consts which define addresses, masks and offsets.

How can i do this in the device_open method?

Please help.

thanks in advance

Reply to
pslana
Loading thread data ...

ioremap ..

Reply to
Geronimo W. Christ Esq

I still have problems.

If i do the following: // mem = open("/dev/mem", O_RDWR | O_SYNC); //base = mmap(0, MAP_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, mem, EBI_BASE & ~MAP_MASK); base = ioremap(EBI_BASE & ~MAP_MASK, MAP_SIZE); // === DO SOMETHIN' DIRECTLY ON IT

*((unsigned long *) (base + (O_SMC_CSR3 & MAP_MASK))) = 0x4494; //munmap(base, MAP_SIZE); iounmap(base); //cs_base = mmap(0, MAP_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, mem, CS_BASE & ~MAP_MASK); cs_base = ioremap(CS_BASE & ~MAP_MASK, MAP_SIZE); // === DO SOMETHIN' DIRECTLY ON IT *((unsigned char *) (cs_base) +3) = 0x0001;

It does actually nothin. If i print the address it is also funny: "c4854000" as the CS_BASE is "0x40000000UL".

Please help ... urgent.

Reply to
pslana

Depending on the arch, you may not be able to do this. You may need readb() and writeb() instead.

Hey, hang on a minute. Why don't you read "Linux Device Drivers" ? It tells you all this stuff.

Reply to
Geronimo W. Christ Esq

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