From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Mundt Date: Tue, 25 Nov 2008 13:18:52 +0000 Subject: Re: [PATCH] sh: P4 ioremap pass-through Message-Id: <20081125131852.GC20883@linux-sh.org> List-Id: References: <20081125125729.8565.28530.sendpatchset@rx1.opensource.se> In-Reply-To: <20081125125729.8565.28530.sendpatchset@rx1.opensource.se> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-sh@vger.kernel.org On Tue, Nov 25, 2008 at 09:57:29PM +0900, Magnus Damm wrote: > From: Magnus Damm > > This patch adds a pass-through case when ioremapping P4 addresses. > > Addresses passed to ioremap() should be physical addresses, so the > best option is usually to convert the virtual address to a physical > address before calling ioremap. This will give you a virtual address > in P2 which matches the physical address and this works well for > most internal hardware blocks on the SuperH architecture. > > However, some hardware blocks must be accessed through P4. Converting > the P4 address to a physical and then back to a P2 does not work. One > example of this is the sh7722 TMU block, it must be accessed through P4. > > Without this patch P4 addresses will be mapped using PTEs which > requires the page allocator to be up and running. > > Signed-off-by: Magnus Damm Applied, thanks.