= GIET-VM / Physical addressing functions =

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The [source:soft/giet_vm/giet_common/utils.c utils.c] and [source:soft/giet_vm/giet_common/utils.h util.h] files define the functions related to physical addressing, using the CP2_PADDR_EXT register, or functions used for software L2/L3 cache coherence. 
Physical addresses can have up to 64 bits.

They are prefixed by "_" to remind that they can only be executed by a processor in kernel mode.

 === 1) unsigned int '''_physical_read'''( unsigned long long paddr ) ===
Returns the 32 bits word stored at physical address ''paddr'', after a temporary DTLB deactivation.
It uses the CP2_PADDR_EXT register.

 === 2) void '''_physical_write'''( unsigned long long paddr, unsigned int value )
Writes the 32 bits word ''value'' at physical address ''paddr'', after a temporary DTLB deactivation.
It uses the CP2_PADDR_EXT register.

 === 3) unsigned long long '''_physical_read_ull'''( unsigned long long paddr ) ===
Returns the 64 bits word stored at physical address ''paddr'', after a temporary DTLB deactivation.
It uses the CP2_PADDR_EXT register.

 === 4) void '''_physical_write_ull'''( unsigned long long paddr, unsigned long long value ) ===
Writes the 64 bits word ''value'' at physical address ''paddr'', after a temporary DTLB deactivation.
It uses the CP2_PADDR_EXT register.

 === 5) void '''_physical_memcpy'''( unsigned long long dst_paddr, unsigned long long src paddr, unsigned int size ) ===
This function makes a memcpy from a source buffer to a destination buffer, using physical addresses, after a temporary DTLB de-activation. The ''src_paddr'', ''dst_paddr'' and ''size'' arguments must be multiple of 4 bytes. 

 === 6) unsigned int '''_io_extended_read'''( unsigned int* vaddr ) ===
This function is used by the GIET-VM drivers to read a 32 bits word in a peripheral register.
If the MMU is not activated, the virtual address is extended using X_IO and Y_IO (defined in the hard-config.h file) to reach the cluster_io.

 === 7) void '''_io_extended_write'''( unsigned int* vaddr, unsigned int value ) ===
This function is used by the GIET-VM drivers to write a 32 bits word in a peripheral register.
If the MMU is not activated, the virtual address is extended using X_IO and Y_IO (defined in the hard-config.h file) to reach the cluster_io.

 === 8) unsigned int '''_l2_l3_sync_read'''( unsigned int* vaddr ) ===
This function is used by the GIET_VM drivers to write a 32 bits word in L2 cache, with the garanty that the L3 cache will be updated.

 === 9) void '''_l2_l3_sync_write'''( unsigned int* vaddr, unsigned int value ) ===
This function is used by the GIET_VM drivers to read a 32 bits word from L2 cache, with the garanty that the involved cache line has
been perviously invalidated.