From: Will Deacon <will@kernel.org>
To: John Stultz <john.stultz@linaro.org>
Cc: Marc Zyngier <maz@kernel.org>,
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
Subject: Re: [RFC][PATCH 5/5] firmware: QCOM_SCM: Allow qcom_scm driver to be loadable as a permenent module
Date: Fri, 3 Jul 2020 13:23:44 +0100 [thread overview]
Message-ID: <20200703122343.GB18652@willie-the-truck> (raw)
In-Reply-To: <CALAqxLUZBdiLBRcp1GW9rGxt1KhgNVQ86MuPXZcXdx2wFLZk6w@mail.gmail.com>
On Tue, Jun 16, 2020 at 01:52:32PM -0700, John Stultz wrote:
> 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?
Can you use symbol_get() or something like that? How are module dependencies
handled by other drivers?
Will
WARNING: multiple messages have this Message-ID (diff)
From: Will Deacon <will@kernel.org>
To: John Stultz <john.stultz@linaro.org>
Cc: 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>,
Bjorn Andersson <bjorn.andersson@linaro.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: [RFC][PATCH 5/5] firmware: QCOM_SCM: Allow qcom_scm driver to be loadable as a permenent module
Date: Fri, 3 Jul 2020 13:23:44 +0100 [thread overview]
Message-ID: <20200703122343.GB18652@willie-the-truck> (raw)
In-Reply-To: <CALAqxLUZBdiLBRcp1GW9rGxt1KhgNVQ86MuPXZcXdx2wFLZk6w@mail.gmail.com>
On Tue, Jun 16, 2020 at 01:52:32PM -0700, John Stultz wrote:
> 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?
Can you use symbol_get() or something like that? How are module dependencies
handled by other drivers?
Will
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2020-07-03 12:23 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
2020-06-16 20:52 ` John Stultz
2020-07-03 12:23 ` Will Deacon [this message]
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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