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From: John Stultz <john.stultz@linaro.org>
To: Marc Zyngier <maz@kernel.org>
Cc: lkml <linux-kernel@vger.kernel.org>,
	Andy Gross <agross@kernel.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Joerg Roedel <joro@8bytes.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Jason Cooper <jason@lakedaemon.net>,
	Linus Walleij <linus.walleij@linaro.org>,
	Lina Iyer <ilina@codeaurora.org>,
	Saravana Kannan <saravanak@google.com>,
	Todd Kjos <tkjos@google.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-arm-msm <linux-arm-msm@vger.kernel.org>,
	iommu@lists.linux-foundation.org, linux-gpio@vger.kernel.org,
	Will Deacon <will@kernel.org>
Subject: Re: [RFC][PATCH 5/5] firmware: QCOM_SCM: Allow qcom_scm driver to be loadable as a permenent module
Date: Tue, 16 Jun 2020 13:52:32 -0700	[thread overview]
Message-ID: <CALAqxLUZBdiLBRcp1GW9rGxt1KhgNVQ86MuPXZcXdx2wFLZk6w@mail.gmail.com> (raw)
In-Reply-To: <0be86735238a0f8b0c25934e2ed39eee@kernel.org>

On Tue, Jun 16, 2020 at 12:55 AM Marc Zyngier <maz@kernel.org> wrote:
> On 2020-06-16 07:13, 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
>
> This looks a bit ugly. Could you explain why we need this at the SMMU
> level? I'd have expected the dependency to flow the other way around...

Yea, so the arm-smmu-qcom.c file calls directly into the qcom-scm code
via qcom_scm_qsmmu500_wait_safe_toggle()
  https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/iommu/arm-smmu-qcom.c?h=v5.8-rc1#n44

So if ARM_SMMU=y and QCOM_SCM=m we get:
drivers/iommu/arm-smmu-qcom.o: In function `qcom_smmu500_reset':
arm-smmu-qcom.c:(.text+0xb4): undefined reference to
`qcom_scm_qsmmu500_wait_safe_toggle'

Do you have a suggestion for an alternative approach?

thanks
-john

WARNING: multiple messages have this Message-ID (diff)
From: John Stultz <john.stultz@linaro.org>
To: Marc Zyngier <maz@kernel.org>
Cc: Jason Cooper <jason@lakedaemon.net>,
	Saravana Kannan <saravanak@google.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	lkml <linux-kernel@vger.kernel.org>,
	Lina Iyer <ilina@codeaurora.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	linux-gpio@vger.kernel.org, iommu@lists.linux-foundation.org,
	Andy Gross <agross@kernel.org>,
	linux-arm-msm <linux-arm-msm@vger.kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Will Deacon <will@kernel.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	Todd Kjos <tkjos@google.com>
Subject: Re: [RFC][PATCH 5/5] firmware: QCOM_SCM: Allow qcom_scm driver to be loadable as a permenent module
Date: Tue, 16 Jun 2020 13:52:32 -0700	[thread overview]
Message-ID: <CALAqxLUZBdiLBRcp1GW9rGxt1KhgNVQ86MuPXZcXdx2wFLZk6w@mail.gmail.com> (raw)
In-Reply-To: <0be86735238a0f8b0c25934e2ed39eee@kernel.org>

On Tue, Jun 16, 2020 at 12:55 AM Marc Zyngier <maz@kernel.org> wrote:
> On 2020-06-16 07:13, 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
>
> This looks a bit ugly. Could you explain why we need this at the SMMU
> level? I'd have expected the dependency to flow the other way around...

Yea, so the arm-smmu-qcom.c file calls directly into the qcom-scm code
via qcom_scm_qsmmu500_wait_safe_toggle()
  https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/iommu/arm-smmu-qcom.c?h=v5.8-rc1#n44

So if ARM_SMMU=y and QCOM_SCM=m we get:
drivers/iommu/arm-smmu-qcom.o: In function `qcom_smmu500_reset':
arm-smmu-qcom.c:(.text+0xb4): undefined reference to
`qcom_scm_qsmmu500_wait_safe_toggle'

Do you have a suggestion for an alternative approach?

thanks
-john
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

  reply	other threads:[~2020-06-16 20:52 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-16  6:13 [RFC][PATCH 0/5] Allow for qcom-pdc, pinctrl-msm and qcom-scm drivers to be loadable as modules John Stultz
2020-06-16  6:13 ` John Stultz
2020-06-16  6:13 ` [RFC][PATCH 1/5] irq: irqdomain: Export irq_domain_update_bus_token John Stultz
2020-06-16  6:13   ` John Stultz
2020-06-16  6:13 ` [RFC][PATCH 2/5] irq: irqchip: Export irq_chip_retrigger_hierarchy and irq_chip_set_vcpu_affinity_parent John Stultz
2020-06-16  6:13   ` John Stultz
2020-06-16  6:13 ` [RFC][PATCH 3/5] irqchip: Allow QCOM_PDC to be loadable as a perment module John Stultz
2020-06-16  6:13   ` John Stultz
2020-06-16 11:29   ` Maulik Shah
2020-06-16 11:29     ` Maulik Shah
2020-06-16 16:08     ` Lina Iyer
2020-06-16 16:08       ` Lina Iyer
2020-06-16 21:21     ` John Stultz
2020-06-16 21:21       ` John Stultz
2020-06-16  6:13 ` [RFC][PATCH 4/5] pinctrl: qcom: Allow pinctrl-msm code to be loadable as a module John Stultz
2020-06-16  6:13   ` John Stultz
2020-06-20 21:21   ` Linus Walleij
2020-06-20 21:21     ` Linus Walleij
2020-06-21  6:00   ` Bjorn Andersson
2020-06-21  6:00     ` Bjorn Andersson
2020-06-24 23:22     ` John Stultz
2020-06-24 23:22       ` John Stultz
2020-06-16  6:13 ` [RFC][PATCH 5/5] firmware: QCOM_SCM: Allow qcom_scm driver to be loadable as a permenent module John Stultz
2020-06-16  6:13   ` John Stultz
2020-06-16  7:55   ` Marc Zyngier
2020-06-16  7:55     ` Marc Zyngier
2020-06-16 20:52     ` John Stultz [this message]
2020-06-16 20:52       ` John Stultz
2020-07-03 12:23       ` Will Deacon
2020-07-03 12:23         ` Will Deacon
2020-07-03 12:49         ` Vinod Koul
2020-07-03 12:49           ` Vinod Koul

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