From mboxrd@z Thu Jan 1 00:00:00 1970 From: agraf@suse.de (Alexander Graf) Date: Fri, 11 Mar 2016 18:52:54 +0100 Subject: [PATCH 0/8] EFI framebuffer support for ARM and arm64 In-Reply-To: References: <1457588408-19309-1-git-send-email-ard.biesheuvel@linaro.org> <56E19CD1.6080409@redhat.com> Message-ID: <56E305F6.5070402@suse.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 10.03.16 17:23, Ard Biesheuvel wrote: > (+ Laszlo) > > On 10 March 2016 at 23:12, Mark Langsdorf wrote: >> On 03/09/2016 11:40 PM, Ard Biesheuvel wrote: >>> >>> This series adds support to ARM and arm64 for using the kernel's EFI >>> framebuffer driver to drive EFI Graphics Output Protocol (GOP) based >>> framebuffers. >>> >>> This involves refactoring some of the existing x86 code so it can be >>> reused >>> by ARM and arm64, and wiring it up both in the UEFI stub and in the core >>> kernel into the existing UEFI infrastructure for ARM and arm64. >> >> >> Given that I have access to a variety of different ARM64 UEFI >> implementations, how would I go about testing this code? Do I >> need a specific UEFI implementation and are there any special >> command line arguments I should pass to the kernel? >> > > I have tested this myself on QEMU and FVP Base, which are both > software models. On bare metal, it would involve a system with a > graphics card that the firmware knows how to drive, and I am honestly > not sure if any such combinations currently exist, other than the ARM > development platforms such as Juno which have an embedded-style (i.e., > non-PCI) graphics controller that the firmware knows how to drive out > of the box. > > The code itself is smart enough to figure which (if any) of the > available handles carrying the GOP protocol is the one that is > attached to ConOut, and so there is nothing required to enable this > other than building it into the kernel and running it on a system with > a firmware supported screen attached. > How does this deal with caches? Does the GOP driver access the frame buffer as cached or as uncached memory? I suppose it's always uncached? I'm mostly curious because I'd like to implement support for GOP in U-Boot soon. Alex