From: Will Deacon <will@kernel.org>
To: John Stultz <john.stultz@linaro.org>
Cc: Maulik Shah <mkshah@codeaurora.org>,
Jason Cooper <jason@lakedaemon.net>,
Saravana Kannan <saravanak@google.com>,
Marc Zyngier <maz@kernel.org>,
lkml <linux-kernel@vger.kernel.org>,
Lina Iyer <ilina@codeaurora.org>,
linux-gpio@vger.kernel.org, iommu@lists.linux-foundation.org,
Andy Gross <agross@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Linus Walleij <linus.walleij@linaro.org>,
linux-arm-msm <linux-arm-msm@vger.kernel.org>,
Todd Kjos <tkjos@google.com>
Subject: Re: [PATCH v2 5/5] firmware: QCOM_SCM: Allow qcom_scm driver to be loadable as a permenent module
Date: Fri, 10 Jul 2020 08:54:12 +0100 [thread overview]
Message-ID: <20200710075411.GA30011@willie-the-truck> (raw)
In-Reply-To: <CALAqxLVZ2EhutYjOt7Be1RgnYwHT6-4m6DxA-t1wuxuSy=6yDQ@mail.gmail.com>
On Thu, Jul 09, 2020 at 08:28:45PM -0700, John Stultz wrote:
> On Thu, Jul 2, 2020 at 7:18 AM Will Deacon <will@kernel.org> wrote:
> > On Thu, Jun 25, 2020 at 12:10:39AM +0000, John Stultz wrote:
> > > diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
> > > index b510f67dfa49..714893535dd2 100644
> > > --- a/drivers/iommu/Kconfig
> > > +++ b/drivers/iommu/Kconfig
> > > @@ -381,6 +381,7 @@ config SPAPR_TCE_IOMMU
> > > config ARM_SMMU
> > > tristate "ARM Ltd. System MMU (SMMU) Support"
> > > depends on (ARM64 || ARM || (COMPILE_TEST && !GENERIC_ATOMIC64)) && MMU
> > > + depends on QCOM_SCM || !QCOM_SCM #if QCOM_SCM=m this can't be =y
> > > select IOMMU_API
> > > select IOMMU_IO_PGTABLE_LPAE
> > > select ARM_DMA_USE_IOMMU if ARM
> >
> > This looks like a giant hack. Is there another way to handle this?
>
> Sorry for the slow response here.
>
> So, I agree the syntax looks strange (requiring a comment obviously
> isn't a good sign), but it's a fairly common way to ensure drivers
> don't get built in if they optionally depend on another driver that
> can be built as a module.
> See "RFKILL || !RFKILL", "EXTCON || !EXTCON", or "USB_GADGET ||
> !USB_GADGET" in various Kconfig files.
>
> I'm open to using a different method, and in a different thread you
> suggested using something like symbol_get(). I need to look into it
> more, but that approach looks even more messy and prone to runtime
> failures. Blocking the unwanted case at build time seems a bit cleaner
> to me, even if the syntax is odd.
Maybe just split it out then, so that the ARM_SMMU entry doesn't have this,
as that driver _really_ doesn't care about SoC details like this. In other
words, add a new entry along the lines of:
config ARM_SMMU_QCOM_IMPL
default y
#if QCOM_SCM=m this can't be =y
depends on ARM_SMMU & (QCOM_SCM || !QCOM_SCM)
and then have arm-smmu.h provide a static inline qcom_smmu_impl_init()
which returns -ENODEV if CONFIG_ARM_SMMU_QCOM_IMPL=n and hack the Makefile
so that we don't bother to compile arm-smmu-qcom.o in that case.
Would that work?
Will
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iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2020-07-10 7:54 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-25 0:10 [PATCH v2 0/5] Allow for qcom-pdc, pinctrl-msm and qcom-scm drivers to be loadable as modules John Stultz
2020-06-25 0:10 ` [PATCH v2 1/5] irq: irqdomain: Export irq_domain_update_bus_token John Stultz
2020-06-25 0:10 ` [PATCH v2 2/5] irq: irqchip: Export irq_chip_retrigger_hierarchy and irq_chip_set_vcpu_affinity_parent John Stultz
2020-06-25 0:10 ` [PATCH v2 3/5] irqchip: Allow QCOM_PDC to be loadable as a permanent module John Stultz
2020-06-26 7:42 ` Stephen Boyd
2020-06-27 1:34 ` John Stultz
2020-06-27 9:37 ` Marc Zyngier
2020-07-10 6:02 ` Stephen Boyd
2020-07-10 22:44 ` John Stultz
2020-07-10 23:27 ` Stephen Boyd
2020-07-12 9:27 ` Marc Zyngier
2020-06-25 0:10 ` [PATCH v2 4/5] pinctrl: qcom: Allow pinctrl-msm code to be loadable as a module John Stultz
2020-06-25 0:10 ` [PATCH v2 5/5] firmware: QCOM_SCM: Allow qcom_scm driver to be loadable as a permenent module John Stultz
2020-07-02 12:47 ` Greg Kroah-Hartman
2020-07-02 14:18 ` Will Deacon
2020-07-10 3:28 ` John Stultz
2020-07-10 7:54 ` Will Deacon [this message]
2020-07-10 22:21 ` John Stultz
2020-07-13 20:41 ` Will Deacon
2020-07-13 20:48 ` John Stultz
2020-07-14 7:56 ` Will Deacon
2020-10-28 5:53 ` John Stultz
2020-10-28 13:51 ` Will Deacon
2020-10-28 14:51 ` Robin Murphy
2020-10-30 1:02 ` John Stultz
2020-10-30 14:12 ` Robin Murphy
2020-10-31 0:12 ` John Stultz
2020-10-30 6:09 ` John Stultz
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