From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Osipenko Subject: [PATCH v1 1/3] ARM: tegra: Initialize r0 register for firmware wake-up Date: Wed, 25 Mar 2020 01:43:33 +0300 Message-ID: <20200324224335.5825-2-digetx@gmail.com> References: <20200324224335.5825-1-digetx@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20200324224335.5825-1-digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Thierry Reding , Jonathan Hunter , Peter De Schrijver , "Rafael J. Wysocki" , Daniel Lezcano , =?UTF-8?q?Micha=C5=82=20Miros=C5=82aw?= , Jasper Korten , David Heidelberg , Peter Geis Cc: linux-pm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-tegra@vger.kernel.org Downstream kernel of ASUS TF300T sets r0 to #3. There is no explanation in downstream code whether this is really needed and some of T30 downstream kernels have and explicit comment telling that all arguments are ignored by firmware. Let's take a safe side by replicating behavior of the TF300T downstream kernel. This change works fine on Ouya and Nexus 7 devices. Tested-by: Michał Mirosław Tested-by: Jasper Korten Tested-by: David Heidelberg Tested-by: Peter Geis Signed-off-by: Dmitry Osipenko --- arch/arm/mach-tegra/reset-handler.S | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/arm/mach-tegra/reset-handler.S b/arch/arm/mach-tegra/reset-handler.S index 53123ae4ac3b..06ca44b09381 100644 --- a/arch/arm/mach-tegra/reset-handler.S +++ b/arch/arm/mach-tegra/reset-handler.S @@ -98,7 +98,12 @@ ENTRY(tegra_resume_trusted_foundations) reteq lr .arch_extension sec - /* First call after suspend wakes firmware. No arguments required. */ + /* + * First call after suspend wakes firmware. No arguments required + * for some firmware versions. Downstream kernel of ASUS TF300T uses + * r0=3 for the wake-up notification. + */ + mov r0, #3 smc #0 b cpu_resume -- 2.25.1