From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <3EBA4D38.5030905@embeddededge.com> Date: Thu, 08 May 2003 08:27:36 -0400 From: Dan Malek MIME-Version: 1.0 To: "Kerl, John" Cc: "'linuxppc-embedded@lists.linuxppc.org'" Subject: Re: mm_ptov() in pgtable.c References: Content-Type: text/plain; charset=us-ascii; format=flowed Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: Kerl, John wrote: > Does anyone know why we have mm_ptov() in > arch/ppc/mm/pgtable.c, since we already > have __va? They are different functions. The __va() macro does simple arithmetic on the 1:1 kernel mapped low memory addresses. The mm_ptov() is supposed to do the opposite of where we use iopa(), which can be used on the entire virtual address space. Since there isn't sufficient information in the kernel to properly implement mm_ptov() in a generic way, it's implementation has been stalled and we have used a variety of different methods to return physical addresses dependent on the way memory has been mapped (which unfortunately seems to be the Linux design preference). The APUS configuration uses mm_ptov, I kind of broke it at one point and I'm waiting for them to stumble across it so we can fix it for them. -- Dan ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/