From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Osipenko Subject: Re: [PATCH V6 01/21] irqchip: tegra: Do not disable COP IRQ during suspend Date: Fri, 26 Jul 2019 07:48:11 +0300 Message-ID: <20190726074811.39e0e6cb@dimatab> 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> <20190722193838.0d7cd2ad@why> <8e9f821c-3717-510d-c64f-8a1cc2452c25@gmail.com> <78d5af07-2556-b60d-01d7-3684ebe7040b@nvidia.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <78d5af07-2556-b60d-01d7-3684ebe7040b@nvidia.com> Sender: linux-kernel-owner@vger.kernel.org To: Sowjanya Komatineni Cc: 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, 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 =D0=92 Wed, 24 Jul 2019 16:09:53 -0700 Sowjanya Komatineni =D0=BF=D0=B8=D1=88=D0=B5=D1=82: > On 7/22/19 4:35 PM, Dmitry Osipenko wrote: > > 22.07.2019 21:38, Marc Zyngier =D0=BF=D0=B8=D1=88=D0=B5=D1=82: =20 > >> On Mon, 22 Jul 2019 09:21:21 -0700 > >> Sowjanya Komatineni wrote: > >> =20 > >>> On 7/22/19 3:57 AM, Dmitry Osipenko wrote: =20 > >>>> 22.07.2019 13:13, Marc Zyngier =D0=BF=D0=B8=D1=88=D0=B5=D1=82: =20 > >>>>> On 22/07/2019 10:54, Dmitry Osipenko wrote: =20 > >>>>>> 21.07.2019 22:40, Sowjanya Komatineni =D0=BF=D0=B8=D1=88=D0=B5=D1= =82: =20 > >>>>>>> Tegra210 platforms use sc7 entry firmware to program Tegra > >>>>>>> LP0/SC7 entry sequence and sc7 entry firmware is run from > >>>>>>> COP/BPMP-Lite. > >>>>>>> > >>>>>>> So, COP/BPMP-Lite still need IRQ function to finish SC7 > >>>>>>> suspend sequence 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_soc =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 */ =20 > >>>>>> 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. =20 > >>>>> If what you're saying is true, then the whole patch is wrong, > >>>>> and the SC7 property should come from DT. =20 > >>>> 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. =20 > >>> Yes, all existing Tegra210 platforms uses sc7 entry firmware for > >>> SC7 and AVP/COP IRQ need to be kept enabled as during suspend ATF > >>> triggers IRQ to COP for SC7 entry fw execution. =20 > > Okay, as I already wrote before, it looks to me that a more proper > > solution should be to just remove everything related to COP from > > this driver instead of adding custom quirks for T210. > > > > The disabling / restoring of COP interrupts should be relevant only > > for the multimedia firmware on older Tegra SoCs. That firmware > > won't be ever supported in the upstream simply because NVIDIA > > abandoned the support for older hardware in the downstream and > > because it is not possible due to some legal weirdness (IIUC). The > > only variant for upstream is reverse-engineering of hardware (not > > the firmware BLOB) and writing proper opensource drivers for the > > upstream kernel, which we're already doing and have success to a > > some extent.=20 > >> That's not the question. Dmitry says that the SC7 support is not a > >> property of the SoC, but mostly a platform decision on whether the > >> firmware supports SC7 or not. > >> > >> To me, that's a clear indication that this should not be hardcoded > >> in the driver, but instead obtained dynamically, via DT or > >> otherwise. =20 > > We already have an nvidia,suspend-mode property in the device-tree > > of the Power Management Controller node (all Tegra SoCs) which > > defines what suspending type is supported by a particular board. > > =20 > >>>>>>> + writel_relaxed(~0ul, ictlr + > >>>>>>> ICTLR_COP_IER_CLR); =20 > >>>>>> 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. =20 > >>>>> 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). =20 > >>>> 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.=20 > >>>>> Joseph, can you please shed some light here? =20 > >>> SC7 entry flow uses 3rd party ATF (arm-trusted FW) blob which is > >>> the one that actually loads SC7 entry firmware and triggers IRQ to > >>> AVP/COP which causes 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. =20 > >> This looks like a lot of undocumented assumptions on what firmware > >> does, as well as what firmware *is*. What I gather from this > >> thread is that there is at least two versions of firmware (a > >> "proprietary firmware" for "downstream kernels", and another one > >> for mainline), and that they do different things. > >> > >> Given that we cannot know what people actually run, I don't think > >> we can safely remove anything unless this gets tested on the full > >> spectrum of HW/FW combination. =20 > > I'm not sure whether multiple firmware variations exist in the wild > > for Tegra210. Maybe Sowjanya or somebody else from NVIDIA could > > clarify. I think there should be some efforts in regards to a fully > > opensource firmware on Tegra210, but I'm not following it and have > > no idea about the status. > > > > You're right that there are multiple variants of suspend-resuming > > flow on Tegra SoCs. The older 32bit Tegra SoC generations have a > > variety of options in regards to suspend-resuming, including > > firmware-less variants on platforms that are having kernel running > > in secure mode (dev boards, most of Tegra20 consumer devices) and > > Trusted-Foundations firmware variant for insecure platforms > > (consumer devices). And yes, vendor firmware creates a lot of > > headache in regards to bringing support into upstream because it > > usually does a lot of odd undocumented things which may also vary > > depending on a firmware version (bootloader, etc) and it also > > usually difficult to replace it with an opensource alternative due > > to a crypto signing. =20 >=20 > Tried without this patch which keeps COP IRQ disabled and I see SC7=20 > entry FW execution happens still. >=20 > Digging through the ATF FW code, I see on SC7 entry firmware loading=20 > into IRAM, COP processor is reset with RESET VECTOR set to SC7 entry=20 > firmware location in IRAM and on reset de-assert & unhalt COP, SC7=20 > firmware starts execution. >=20 > Will remove this patch in next version... >=20 Good, sounds like you also verified that SC7 COP firmware doesn't use interrupts.