From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tom Rini Date: Fri, 2 Dec 2016 10:41:50 -0500 Subject: [U-Boot] [RFC PATCH 0/2] ARMv8 Aarch32 support In-Reply-To: <1480679469-27065-1-git-send-email-ryan.harkin@linaro.org> References: <1480679469-27065-1-git-send-email-ryan.harkin@linaro.org> Message-ID: <20161202154150.GP2546@bill-the-cat> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Fri, Dec 02, 2016 at 11:51:07AM +0000, Ryan Harkin wrote: > I've been working with Soby Mathew to get U-Boot booting on ARM's > AEMv8 FVP model in Aarch32 mode. > > Soby worked out what needed to be changed and I'm refining the changes > into patches that can be built for both Aarch64 and Aarch32 mode. > > There are two patches for discussion: > > [RFC PATCH 1/2] Add Aarch32 option for ARMv8 CPUs > [RFC PATCH 2/2] Add vexpress_aemv8a_aarch32 variant > > I expect the first patch to be controversial. I also don't expect it to > be accepted, but to demonstrate what changes we needed to make to get an > ARMv8 platform to boot in Aarch32 mode when selecting CPU_V7 instead of > ARM64 as the CPU type. This in itself may be the wrong approach. > > It adds an ARMV8_AARCH32 config option and some checks in generic code > for that option to allow the code to differentiate between the two > modes. > > The second patch should be less controversial. It adds support for a > new AEMv8 variant that runs in 32-bit mode. The most awkward part is > that it defines itself not as ARM64, but as CPU_V7. I expect this to > change based on feedback from patch 1/2. > > The Aarch32 code runs on the same AEMv8 model as the Aarch64 code, but > takes an extra per-core model launch parameter to switch the cores into > Aarch32 mode, eg. "-C cluster0.cpu0.CONFIG64=0". So my first and slightly ignorant question is, why isn't this just a new regular ARMv7 board being added rather than a special cased ARMv8? -- Tom -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 819 bytes Desc: Digital signature URL: