From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34845) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a4Vfw-0006r3-MY for qemu-devel@nongnu.org; Thu, 03 Dec 2015 10:20:05 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1a4Vfs-00054J-7Z for qemu-devel@nongnu.org; Thu, 03 Dec 2015 10:20:04 -0500 Received: from mail-wm0-x236.google.com ([2a00:1450:400c:c09::236]:38407) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a4Vfr-000548-Tw for qemu-devel@nongnu.org; Thu, 03 Dec 2015 10:20:00 -0500 Received: by wmec201 with SMTP id c201so26708908wme.1 for ; Thu, 03 Dec 2015 07:19:58 -0800 (PST) References: <1447946528-1533-1-git-send-email-eric.auger@linaro.org> <1447946528-1533-3-git-send-email-eric.auger@linaro.org> <5656E590.3040001@redhat.com> From: Eric Auger Message-ID: <56605D80.70402@linaro.org> Date: Thu, 3 Dec 2015 16:19:28 +0100 MIME-Version: 1.0 In-Reply-To: <5656E590.3040001@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RESEND RFC 2/6] device_tree: introduce load_device_tree_from_sysfs List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Thomas Huth , eric.auger@st.com, qemu-devel@nongnu.org, qemu-arm@nongnu.org, alex.williamson@redhat.com, peter.maydell@linaro.org Cc: thomas.lendacky@amd.com, b.reynal@virtualopensystems.com, patches@linaro.org, suravee.suthikulpanit@amd.com, pbonzini@redhat.com, christoffer.dall@linaro.org, David Gibson Hi Thomas, Alex, On 11/26/2015 11:57 AM, Thomas Huth wrote: > On 19/11/15 16:22, Eric Auger wrote: >> This function returns the host device tree blob from sysfs >> (/sys/firmware/devicetree/base). >> >> This has a runtime dependency on the dtc binary. This functionality >> is useful for platform device passthrough where the host device tree >> needs to be parsed to feed information into the guest device tree. >> >> Signed-off-by: Eric Auger >> --- >> device_tree.c | 40 ++++++++++++++++++++++++++++++++++++++++ >> include/sysemu/device_tree.h | 1 + >> 2 files changed, 41 insertions(+) >> >> diff --git a/device_tree.c b/device_tree.c >> index a9f5f8e..58a5329 100644 >> --- a/device_tree.c >> +++ b/device_tree.c >> @@ -117,6 +117,46 @@ fail: >> return NULL; >> } >> >> +/** >> + * load_device_tree_from_sysfs >> + * >> + * extract the dt blob from host sysfs >> + * this has a runtime dependency on the dtc binary >> + */ >> +void *load_device_tree_from_sysfs(void) >> +{ >> + char cmd[] = "dtc -I fs -O dtb /sys/firmware/devicetree/base"; >> + FILE *pipe; >> + void *fdt; >> + int ret, actual_dt_size; >> + >> + pipe = popen(cmd, "r"); >> + if (!pipe) { >> + error_report("%s: Error when executing dtc", __func__); >> + return NULL; >> + } > > The Device Tree Compiler binary is normally only installed on > developer's machines, so I somewhat doubt that it is a good idea to rely > on the availability of that binary in QEMU? Maybe you should rather > extend libfdt to support such a feature? Sorry for the delay and thank you for your review/comments. According to your feedbacks I give up my plan about using dtc binary. Thanks Eric > > Thomas >