From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <3E8C562B.5090709@paulidav.org> Date: Thu, 03 Apr 2003 07:41:31 -0800 From: Vladimir Gurevich MIME-Version: 1.0 To: Donald White Cc: linux-embedded Subject: Re: Question about porting VxWorks driver References: <3E8BECA6.6060709@asu.edu> Content-Type: text/plain; charset=us-ascii; format=flowed Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: Hello Donald, Is it one of Hifn chips by any chance? If yes, then I can tell you that their drivers do not know about cache flushes and invalidates at all, which presents a real challenge on PowerPC. Writeback cache usually won't work. You have to manually flush it before sending a message to the board and invalidate it after you receive the encrypted (decrypted) message back. If you do the transformation "in-place" then you can use flush-and-invalidate before seding the message. Using uncached memory is another option, but if you want to do further processing without copying data to a cached buffer, you performance will likely suffer. In general you keep data buffers in cached memory and do manual flushes/invalidates when needed, but keep buffer descriptors and other similar structures (as well as chip's registers and chip's private memory) in uncached space. Best regards, Vladimir ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/