From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Vasut Date: Tue, 12 Mar 2019 15:40:30 +0100 Subject: [U-Boot] [PATCH 05/10] board: altera: Stratix10: Add board_get_usable_ram_top() In-Reply-To: References: <1552379474-12867-1-git-send-email-ley.foon.tan@intel.com> <1552379474-12867-6-git-send-email-ley.foon.tan@intel.com> Message-ID: <887331a8-0b3c-4363-8a5f-363355edb80d@denx.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On 3/12/19 3:33 PM, Westergreen, Dalon wrote: > On Tue, 2019-03-12 at 11:46 +0100, Marek Vasut wrote: >> On 3/12/19 9:31 AM, Ley Foon Tan wrote: >>> Add board_get_usable_ram_top() function. Limit maximum usable >>> ram top to 2GB. >> >> Why ? There are ARM64 platforms which can access the entire DRAM range >> just fine, what's the problem ? >> > > The issue is the gap in memory between 2GB and 4GB. There is some trickery > you can use to gain access to the memory in that range, but in general, you > dont have access. I believe just setting the banks up in the dts will > resolve this. E.g. the R8A779{5..9}* platforms also have gaps in memory and it all works fine . So unless there's some other specialty, there should be no problem. -- Best regards, Marek Vasut