Hi, I have ported Linux-2.6.18 kernel on MIPS24KE processor. I am using write back cache policy. Could you please guide me under what cases the below cache API's are being used: - dma_cache_wback_inv() : Could you explain what exactly this function does - dma_cache_wback() : This function write back the cache data to memory - dma_cache_inv : This function invalidate the cache tags. so subsequent access will fetch from memory. Once I looked the above function definitions in linux-2.6.18/arch/mips/mm/c-r4k.c. All these function's implemetation are same except bc_wbak_inv() is called in both dma_cache_wback-inv() and dma_cache_wback(), where as bc_inv() is called in case of dma_cache_inv. Also, bc_inv()/bc_wbak_inv are define as null implementation for R4000. That means all three functions are doing same functionality in case of R4000. What are the difference between these three functions. Under what cases these functions are used. Please guide me if you have any links which will explain these API's. Thanks in advance. Regards, Veerasena. Forgot the famous last words? Access your message archive online at http://in.messenger.yahoo.com/webmessengerpromo.php