From mboxrd@z Thu Jan 1 00:00:00 1970 From: dinh.linux@gmail.com (Dinh Nguyen) Date: Wed, 30 Apr 2014 17:06:28 -0500 Subject: [PATCH] arm: socfpga: reserve the region at start of phys mem In-Reply-To: <20140430173220.GZ5546@joshc.qualcomm.com> References: <1392744897-6384-1-git-send-email-bigeasy@linutronix.de> <20140430161717.GY5546@joshc.qualcomm.com> <53612C70.6000109@linutronix.de> <20140430173220.GZ5546@joshc.qualcomm.com> Message-ID: <536173E4.2010404@gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Sebastian, On 4/30/14 12:32 PM, Josh Cartwright wrote: > On Wed, Apr 30, 2014 at 07:01:36PM +0200, Sebastian Andrzej Siewior wrote: >> On 04/30/2014 06:17 PM, Josh Cartwright wrote: >>> Is there a particular reason why you aren't describing this reservation >>> in devicetree using a /memreserve/ node? >> Because the kernel is using memory at a specific address it did not >> allocate. If the memory address where the second CPU come up could be >> set then this node wouldn't be required and a simple kmalloc() would do >> it, too. > I understand the need to reserve the area, but questioning the mechanism > used to do so. How is the socfpga case different from Highbank, for > example, which makes use of /memreserve/ for what appears to be a very > similar purpose (see arch/arm/boot/dts/highbank.dts): > > /* First 4KB has pen for secondary cores. */ > /memreserve/ 0x00000000 0x0001000; > I apologize but it looks like I accidently dropped this patch. But in light of Josh's comments, I think doing the /memreserve/ is the correct way. Dinh