From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44964) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eOiob-0004dJ-82 for qemu-devel@nongnu.org; Tue, 12 Dec 2017 06:33:38 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eOioa-0005dN-CC for qemu-devel@nongnu.org; Tue, 12 Dec 2017 06:33:37 -0500 References: <1512745328-5109-1-git-send-email-peter.maydell@linaro.org> <1512745328-5109-4-git-send-email-peter.maydell@linaro.org> <5A2F6ED9.5030605@huawei.com> From: Laszlo Ersek Message-ID: <6b4b6351-eeb4-a4d3-8ddf-5401516671ae@redhat.com> Date: Tue, 12 Dec 2017 12:33:26 +0100 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 3/3] hw/arm/virt-acpi-build: Add second UART to ACPI tables List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Maydell Cc: Shannon Zhao , qemu-arm , QEMU Developers , "Jason A . Donenfeld" , Drew Jones , Andrea Bolognani , Ard Biesheuvel On 12/12/17 12:11, Peter Maydell wrote: > On 12 December 2017 at 11:06, Laszlo Ersek wrote: >> BTW, has anyone tested this with the ArmVirtQemu firmware? As far as I >> can see from the firmware code, the firmware will use the PL011 whose >> description comes first in the DTB (and ignore the other PL011), in an >> fdt_next_node() traversal. Is that OK for the intended use case? >> (Perhaps I should have asked this under the second patch, which updates >> the DTB generator.) > > I haven't tested, since I don't have a working setup for that to hand. > (Do you have instructions somewhere for getting it working?) The Wiki page I most frequently refer to (for a libvirt-less description anyway) is Ard's: https://wiki.linaro.org/LEG/UEFIforQEMU There's also: https://www.kraxel.org/repos/ https://fedoraproject.org/wiki/Architectures/AArch64/Install_with_QEMU > The behaviour we would want would be for the firmware to keep using > the PL011 at 0x09000000. With these QEMU patches, I reckon that's going to happen, yes. > (In an ideal world the firmware would > prefer the UART marked in the 'stdout-path' in the DTB /chosen node, > as the kernel does, I guess.) Hmmm, I recall that we used to have some code related to the /chosen node... We have a helper function for locating that (GetOrInsertChosenNode), but we no longer use it, it seems? The last (only?) use was apparently removed in: https://github.com/tianocore/edk2/commit/29589acf1010 I'll let Ard comment too. Thanks Laszlo