From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sowjanya Komatineni Subject: Re: [PATCH V6 01/21] irqchip: tegra: Do not disable COP IRQ during suspend Date: Mon, 22 Jul 2019 09:21:21 -0700 Message-ID: References: <1563738060-30213-1-git-send-email-skomatineni@nvidia.com> <1563738060-30213-2-git-send-email-skomatineni@nvidia.com> <20c1d733-60f5-6375-c03c-639de5e41739@arm.com> <0bee8775-756f-adad-4597-8cad53017718@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <0bee8775-756f-adad-4597-8cad53017718@gmail.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Dmitry Osipenko , Marc Zyngier , thierry.reding@gmail.com, jonathanh@nvidia.com, tglx@linutronix.de, jason@lakedaemon.net, linus.walleij@linaro.org, stefan@agner.ch, mark.rutland@arm.com Cc: pdeschrijver@nvidia.com, pgaikwad@nvidia.com, sboyd@kernel.org, linux-clk@vger.kernel.org, linux-gpio@vger.kernel.org, jckuo@nvidia.com, josephl@nvidia.com, talho@nvidia.com, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org, mperttunen@nvidia.com, spatra@nvidia.com, robh+dt@kernel.org, devicetree@vger.kernel.org List-Id: devicetree@vger.kernel.org On 7/22/19 3:57 AM, Dmitry Osipenko wrote: > 22.07.2019 13:13, Marc Zyngier =D0=BF=D0=B8=D1=88=D0=B5=D1=82: >> On 22/07/2019 10:54, Dmitry Osipenko wrote: >>> 21.07.2019 22:40, Sowjanya Komatineni =D0=BF=D0=B8=D1=88=D0=B5=D1=82: >>>> Tegra210 platforms use sc7 entry firmware to program Tegra LP0/SC7 ent= ry >>>> sequence and sc7 entry firmware is run from COP/BPMP-Lite. >>>> >>>> So, COP/BPMP-Lite still need IRQ function to finish SC7 suspend sequen= ce >>>> for Tegra210. >>>> >>>> This patch has fix for leaving the COP IRQ enabled for Tegra210 during >>>> interrupt controller suspend operation. >>>> >>>> Acked-by: Thierry Reding >>>> Signed-off-by: Sowjanya Komatineni >>>> --- >>>> drivers/irqchip/irq-tegra.c | 20 ++++++++++++++++++-- >>>> 1 file changed, 18 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/drivers/irqchip/irq-tegra.c b/drivers/irqchip/irq-tegra.c >>>> index e1f771c72fc4..851f88cef508 100644 >>>> --- a/drivers/irqchip/irq-tegra.c >>>> +++ b/drivers/irqchip/irq-tegra.c >>>> @@ -44,6 +44,7 @@ static unsigned int num_ictlrs; >>>> =20 >>>> struct tegra_ictlr_soc { >>>> unsigned int num_ictlrs; >>>> + bool supports_sc7; >>>> }; >>>> =20 >>>> static const struct tegra_ictlr_soc tegra20_ictlr_soc =3D { >>>> @@ -56,6 +57,7 @@ static const struct tegra_ictlr_soc tegra30_ictlr_so= c =3D { >>>> =20 >>>> static const struct tegra_ictlr_soc tegra210_ictlr_soc =3D { >>>> .num_ictlrs =3D 6, >>>> + .supports_sc7 =3D true, >>>> }; >>>> =20 >>>> static const struct of_device_id ictlr_matches[] =3D { >>>> @@ -67,6 +69,7 @@ static const struct of_device_id ictlr_matches[] =3D= { >>>> =20 >>>> struct tegra_ictlr_info { >>>> void __iomem *base[TEGRA_MAX_NUM_ICTLRS]; >>>> + const struct tegra_ictlr_soc *soc; >>>> #ifdef CONFIG_PM_SLEEP >>>> u32 cop_ier[TEGRA_MAX_NUM_ICTLRS]; >>>> u32 cop_iep[TEGRA_MAX_NUM_ICTLRS]; >>>> @@ -147,8 +150,20 @@ static int tegra_ictlr_suspend(void) >>>> lic->cop_ier[i] =3D readl_relaxed(ictlr + ICTLR_COP_IER); >>>> lic->cop_iep[i] =3D readl_relaxed(ictlr + ICTLR_COP_IEP_CLASS); >>>> =20 >>>> - /* Disable COP interrupts */ >>>> - writel_relaxed(~0ul, ictlr + ICTLR_COP_IER_CLR); >>>> + /* >>>> + * AVP/COP/BPMP-Lite is the Tegra boot processor. >>>> + * >>>> + * Tegra210 system suspend flow uses sc7entry firmware which >>>> + * is executed by COP/BPMP and it includes disabling COP IRQ, >>>> + * clamping CPU rail, turning off VDD_CPU, and preparing the >>>> + * system to go to SC7/LP0. >>>> + * >>>> + * COP/BPMP wakes up when COP IRQ is triggered and runs >>>> + * sc7entry-firmware. So need to keep COP interrupt enabled. >>>> + */ >>>> + if (!lic->soc->supports_sc7) >>>> + /* Disable COP interrupts if SC7 is not supported */ >>> All Tegra SoCs support SC7, hence the 'supports_sc7' and the comment >>> doesn't sound correct to me. Something like 'firmware_sc7' should suit >>> better here. >> If what you're saying is true, then the whole patch is wrong, and the >> SC7 property should come from DT. > It should be safe to assume that all of existing Tegra210 devices use > the firmware for SC7, hence I wouldn't say that the patch is entirely > wrong. To me it's not entirely correct. Yes, all existing Tegra210 platforms uses sc7 entry firmware for SC7 and=20 AVP/COP IRQ need to be kept enabled as during suspend ATF triggers IRQ=20 to COP for SC7 entry fw execution. >>>> + writel_relaxed(~0ul, ictlr + ICTLR_COP_IER_CLR); >>> Secondly, I'm also not sure why COP interrupts need to be disabled for >>> pre-T210 at all, since COP is unused. This looks to me like it was >>> cut-n-pasted from downstream kernel without a good reason and could be >>> simply removed. >> Please verify that this is actually the case. Tegra-2 definitely needed >> some level of poking, and I'm not keen on changing anything there until >> you (or someone else) has verified it on actual HW (see e307cc8941fc). > Tested on Tegra20 and Tegra30, LP1 suspend-resume works perfectly fine > with all COP bits removed from the driver. > > AFAIK, the reason why downstream needed that disabling is that it uses > proprietary firmware which is running on the COP and that firmware is > usually a BLOB audio/video DEC-ENC driver which doesn't cleanup > interrupts after itself. That firmware is not applicable for the > upstream kernel, hence there is no need to care about it. > >> Joseph, can you please shed some light here? SC7 entry flow uses 3rd party ATF (arm-trusted FW) blob which is the one th= at actually loads SC7 entry firmware and triggers IRQ to AVP/COP which caus= es COP to wakeup and run SC7 entry FW. So when SC7 support is enabled, IRQ need to be kept enabled and when SC7 FW= starts execution, it will disable COP IRQ.