From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4FFFBF4C.9070407@snapgear.com> Date: Fri, 13 Jul 2012 16:25:16 +1000 From: Greg Ungerer MIME-Version: 1.0 To: David Woodhouse Subject: Re: [PATCH 1/2] mtd: fix wrong usage of ioremap_nocache() in uclinux.c map driver References: <1336632929-26100-1-git-send-email-gerg@snapgear.com> <1341590150.26921.16.camel@shinybook.infradead.org> <4FFA7576.7050204@snapgear.com> <1342079353.30654.18.camel@shinybook.infradead.org> In-Reply-To: <1342079353.30654.18.camel@shinybook.infradead.org> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Cc: linux-mtd@lists.infradead.org, uclinux-dev@uclinux.org List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 12/07/12 17:49, David Woodhouse wrote: > On Mon, 2012-07-09 at 16:08 +1000, Greg Ungerer wrote: >> >> The only VM based arch this driver can be configured for currently >> is m68k (actually it is even more specific, only CONFIG_COLDFIRE). >> And that doesn't support HIGHMEM. > > OK, can we at least have a comment to that effect in the code, alongside > that phys_to_virt() call so that nobody is tempted to copy it into new > code? And preferably also an '#ifdef CONFIG_HIGHMEM / #error' in the > code or a (redundant) !HIGHMEM dependency in Kconfig just to make sure, > in case it's ever enabled on other architectures or in case HIGHMEM ever > comes to m68k. I'll come up with something and send a patch. >> Can the kernels data region (and the area immediately after it) be in >> high memory? > > No, that'll be in the directly mapped region. Then does it matter whether HIGHMEM is enabled or not? The phys address here is _ebss, the end of the kernels bss section. Regards Greg ------------------------------------------------------------------------ Greg Ungerer -- Principal Engineer EMAIL: gerg@snapgear.com SnapGear Group, McAfee PHONE: +61 7 3435 2888 8 Gardner Close FAX: +61 7 3217 5323 Milton, QLD, 4064, Australia WEB: http://www.SnapGear.com