diff -r 578be2adaf3e -r 307f4279f433 Adaptation/GUID-D2163920-D448-5BFC-B655-B654FD657A94.dita --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/Adaptation/GUID-D2163920-D448-5BFC-B655-B654FD657A94.dita Fri Oct 15 14:32:18 2010 +0100 @@ -0,0 +1,35 @@ + + + + + +Level +2 CacheLevel 2 cache is cache memory that is external to the microprocessor. +The kernel provides functions to perform operations on this cache. +

In general, the presence of Level 2 cache is transparent to device drivers. +The cache is physically indexed and physically tagged, and this means that +L2 cache is not affected by the remapping of virtual-to-physical addresses +in the MMU.

+

However, where data is being transferred using DMA, then cached information +in the data buffers involved in a DMA transfer must be flushed before a DMA +write operation, for example when transferring data from memory to a peripheral, +and both before and after a DMA read operation, for example when transferring +data from a peripheral into memory.

+

The kernel provides three functions for this:

+ +

All three functions are defined and implemented as part of the Cache class, +defined in ...\e32\e32\include\kernel\cache.h.

+

See also DMA +buffers in the Device +Driver Tutorial.

+
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