From mboxrd@z Thu Jan 1 00:00:00 1970 From: Franck Bui-Huu Date: Thu, 14 Feb 2008 19:39:28 +0000 Subject: Re: ioremap() on SH Message-Id: <47B498F0.7010904@gmail.com> List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-sh@vger.kernel.org Paul Mundt wrote: > 0xa000000 is the P2 base, which is the uncached start. In this case > PXSEG(0xa0000000) = 0xa0000000, so it depends on what you specify as the > ioremap flags. If you want a cacheable mapping, you will get back > 0x80000000 which is the cached equivalent of that address. If you want it > uncached, you will get back 0xa0000000. 0x80000000 and 0xa0000000 point > at exactly the same thing, just with different caching attributes. > Do you think that such mapping is correct ? That is to access a device at 0xa000 0000 (physical address), I can use the virtual address 0xa000 0000 or 0x8000 0000 ? In this case shouldn't we use the TLB instead to access the device ? IOW shouldn't ioremap() return a virtual address in P3 segment ? Thanks Franck