From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <39357BC5.A0B3E713@ccrl.mot.com> Date: Wed, 31 May 2000 15:53:25 -0500 From: Steve Rossi MIME-Version: 1.0 To: Dan Malek CC: Embedded Linux PPC List Subject: Re: allocating non-cacheable regions References: <39104A07.D997B6C5@ccrl.mot.com> <3910838C.986942D6@embeddededge.com> Content-Type: text/plain; charset=us-ascii Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: I'm back on this ... with another question. Following the examples in commproc.c and enet.c - does setting the _PAGE_NO_CACHE flag for a page table entry also invalidate any cached data for that page? I am observing a write-though behavior when I write to addresses in the _PAGE_NO_CACHE page but when I read from addresses marked as _PAGE_NO_CACHE it appears to be retrieving data from the cache not from memory. Is this expected behavior? How can I make it so that reads as well as writes to a particular page bypass the cache? Thanks, Steve Dan Malek wrote: > Steve Rossi wrote: > > > > How do I allocate a region of memory that is flagged as being > > non-cacheable? > > For an example, look at the commproc.c or enet.c driver in the > arch/ppc/8xx_io directory. When pages are allocated, the PTEs are > tracked down and marked non-cache. > -- ------------------------------------------------------- Steven K. Rossi srossi@ccrl.mot.com Staff Engineer Multimedia Communications Research Laboratory Motorola Labs ------------------------------------------------------- ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/