Re: [PATCH] [RFC] qcom_scm: hide Kconfig symbol

2021-09-29 Thread Arnd Bergmann
On Wed, Sep 29, 2021 at 4:46 PM Bjorn Andersson
 wrote:
>
> On Wed 29 Sep 05:04 CDT 2021, Arnd Bergmann wrote:
>
> > On Wed, Sep 29, 2021 at 11:51 AM Will Deacon  wrote:
> > > On Mon, Sep 27, 2021 at 05:22:13PM +0200, Arnd Bergmann wrote:
> > > >
> > > > diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
> > > > index 124c41adeca1..989c83acbfee 100644
> > > > --- a/drivers/iommu/Kconfig
> > > > +++ b/drivers/iommu/Kconfig
> > > > @@ -308,7 +308,7 @@ config APPLE_DART
> > > >  config ARM_SMMU
> > > >   tristate "ARM Ltd. System MMU (SMMU) Support"
> > > >   depends on ARM64 || ARM || (COMPILE_TEST && !GENERIC_ATOMIC64)
> > > > - depends on QCOM_SCM || !QCOM_SCM #if QCOM_SCM=m this can't be =y
> > > > + select QCOM_SCM
> > > >   select IOMMU_API
> > > >   select IOMMU_IO_PGTABLE_LPAE
> > > >   select ARM_DMA_USE_IOMMU if ARM
> > >
> > > I don't want to get in the way of this patch because I'm also tired of the
> > > randconfig failures caused by QCOM_SCM. However, ARM_SMMU is applicable to
> > > a wide variety of (non-qcom) SoCs and so it seems a shame to require the
> > > QCOM_SCM code to be included for all of those when it's not strictly 
> > > needed
> > > at all.
> >
> > Good point, I agree that needs to be fixed. I think this additional
> > change should do the trick:
> >
>
> ARM_SMMU and QCOM_IOMMU are two separate implementations and both uses
> QCOM_SCM. So both of them should select QCOM_SCM.

Right, I figured that out later as well.

> "Unfortunately" the Qualcomm portion of ARM_SMMU is builtin
> unconditionally, so going with something like select QCOM_SCM if
> ARCH_QCOM would still require the stubs in qcom_scm.h.

Yes, sounds good. I also noticed that I still need one hack in there
if I do this:

diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
index 55690af1b25d..36c304a8fc9b 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
@@ -427,6 +427,9 @@ struct arm_smmu_device *qcom_smmu_impl_init(struct
arm_smmu_device *smmu)
 {
const struct device_node *np = smmu->dev->of_node;

+   if (!IS_ENABLED(CONFIG_QCOM_SCM))
+   return ERR_PTR(-ENXIO);
+
 #ifdef CONFIG_ACPI
if (np == NULL) {
/* Match platform for ACPI boot */


Otherwise it still breaks with ARM_SMMU=y and QCOM_SCM=m.

Splitting out the qualcomm portion of the arm_smmu driver using
a separate 'bool' symbol should also work, if  you prefer that
and can suggest a name and help text for that symbol. It would
look like

diff --git a/drivers/iommu/arm/arm-smmu/Makefile
b/drivers/iommu/arm/arm-smmu/Makefile
index e240a7bcf310..b0cc01aa20c9 100644
--- a/drivers/iommu/arm/arm-smmu/Makefile
+++ b/drivers/iommu/arm/arm-smmu/Makefile
@@ -1,4 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_QCOM_IOMMU) += qcom_iommu.o
 obj-$(CONFIG_ARM_SMMU) += arm_smmu.o
-arm_smmu-objs += arm-smmu.o arm-smmu-impl.o arm-smmu-nvidia.o arm-smmu-qcom.o
+arm_smmu-objs += arm-smmu.o arm-smmu-impl.o arm-smmu-nvidia.o
+arm_smmu-$(CONFIG_ARM_SMMU_QCOM) += arm-smmu-qcom.o
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-impl.c
b/drivers/iommu/arm/arm-smmu/arm-smmu-impl.c
index 9f465e146799..2c25cce38060 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu-impl.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu-impl.c
@@ -215,7 +215,8 @@ struct arm_smmu_device *arm_smmu_impl_init(struct
arm_smmu_device *smmu)
of_device_is_compatible(np, "nvidia,tegra186-smmu"))
return nvidia_smmu_impl_init(smmu);

-   smmu = qcom_smmu_impl_init(smmu);
+   if (IS_ENABLED(CONFIG_ARM_SMMU_QCOM))
+   smmu = qcom_smmu_impl_init(smmu);

if (of_device_is_compatible(np, "marvell,ap806-smmu-500"))
smmu->impl = _mmu500_impl;



   Arnd
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Re: [PATCH] [RFC] qcom_scm: hide Kconfig symbol

2021-09-29 Thread Bjorn Andersson
On Wed 29 Sep 05:04 CDT 2021, Arnd Bergmann wrote:

> On Wed, Sep 29, 2021 at 11:51 AM Will Deacon  wrote:
> > On Mon, Sep 27, 2021 at 05:22:13PM +0200, Arnd Bergmann wrote:
> > >
> > > diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
> > > index 124c41adeca1..989c83acbfee 100644
> > > --- a/drivers/iommu/Kconfig
> > > +++ b/drivers/iommu/Kconfig
> > > @@ -308,7 +308,7 @@ config APPLE_DART
> > >  config ARM_SMMU
> > >   tristate "ARM Ltd. System MMU (SMMU) Support"
> > >   depends on ARM64 || ARM || (COMPILE_TEST && !GENERIC_ATOMIC64)
> > > - depends on QCOM_SCM || !QCOM_SCM #if QCOM_SCM=m this can't be =y
> > > + select QCOM_SCM
> > >   select IOMMU_API
> > >   select IOMMU_IO_PGTABLE_LPAE
> > >   select ARM_DMA_USE_IOMMU if ARM
> >
> > I don't want to get in the way of this patch because I'm also tired of the
> > randconfig failures caused by QCOM_SCM. However, ARM_SMMU is applicable to
> > a wide variety of (non-qcom) SoCs and so it seems a shame to require the
> > QCOM_SCM code to be included for all of those when it's not strictly needed
> > at all.
> 
> Good point, I agree that needs to be fixed. I think this additional
> change should do the trick:
> 

ARM_SMMU and QCOM_IOMMU are two separate implementations and both uses
QCOM_SCM. So both of them should select QCOM_SCM.

"Unfortunately" the Qualcomm portion of ARM_SMMU is builtin
unconditionally, so going with something like select QCOM_SCM if
ARCH_QCOM would still require the stubs in qcom_scm.h.

Regards,
Bjorn

> --- a/drivers/iommu/Kconfig
> +++ b/drivers/iommu/Kconfig
> @@ -308,7 +308,6 @@ config APPLE_DART
>  config ARM_SMMU
> tristate "ARM Ltd. System MMU (SMMU) Support"
> depends on ARM64 || ARM || (COMPILE_TEST && !GENERIC_ATOMIC64)
> -   select QCOM_SCM
> select IOMMU_API
> select IOMMU_IO_PGTABLE_LPAE
> select ARM_DMA_USE_IOMMU if ARM
> @@ -438,7 +437,7 @@ config QCOM_IOMMU
> # Note: iommu drivers cannot (yet?) be built as modules
> bool "Qualcomm IOMMU Support"
> depends on ARCH_QCOM || (COMPILE_TEST && !GENERIC_ATOMIC64)
> -   depends on QCOM_SCM=y
> +   select QCOM_SCM
> select IOMMU_API
> select IOMMU_IO_PGTABLE_LPAE
> select ARM_DMA_USE_IOMMU
> 
> I'll see if that causes any problems for the randconfig builds.
> 
>Arnd
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Re: [PATCH] [RFC] qcom_scm: hide Kconfig symbol

2021-09-29 Thread Arnd Bergmann
On Wed, Sep 29, 2021 at 11:51 AM Will Deacon  wrote:
> On Mon, Sep 27, 2021 at 05:22:13PM +0200, Arnd Bergmann wrote:
> >
> > diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
> > index 124c41adeca1..989c83acbfee 100644
> > --- a/drivers/iommu/Kconfig
> > +++ b/drivers/iommu/Kconfig
> > @@ -308,7 +308,7 @@ config APPLE_DART
> >  config ARM_SMMU
> >   tristate "ARM Ltd. System MMU (SMMU) Support"
> >   depends on ARM64 || ARM || (COMPILE_TEST && !GENERIC_ATOMIC64)
> > - depends on QCOM_SCM || !QCOM_SCM #if QCOM_SCM=m this can't be =y
> > + select QCOM_SCM
> >   select IOMMU_API
> >   select IOMMU_IO_PGTABLE_LPAE
> >   select ARM_DMA_USE_IOMMU if ARM
>
> I don't want to get in the way of this patch because I'm also tired of the
> randconfig failures caused by QCOM_SCM. However, ARM_SMMU is applicable to
> a wide variety of (non-qcom) SoCs and so it seems a shame to require the
> QCOM_SCM code to be included for all of those when it's not strictly needed
> at all.

Good point, I agree that needs to be fixed. I think this additional
change should do the trick:

--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -308,7 +308,6 @@ config APPLE_DART
 config ARM_SMMU
tristate "ARM Ltd. System MMU (SMMU) Support"
depends on ARM64 || ARM || (COMPILE_TEST && !GENERIC_ATOMIC64)
-   select QCOM_SCM
select IOMMU_API
select IOMMU_IO_PGTABLE_LPAE
select ARM_DMA_USE_IOMMU if ARM
@@ -438,7 +437,7 @@ config QCOM_IOMMU
# Note: iommu drivers cannot (yet?) be built as modules
bool "Qualcomm IOMMU Support"
depends on ARCH_QCOM || (COMPILE_TEST && !GENERIC_ATOMIC64)
-   depends on QCOM_SCM=y
+   select QCOM_SCM
select IOMMU_API
select IOMMU_IO_PGTABLE_LPAE
select ARM_DMA_USE_IOMMU

I'll see if that causes any problems for the randconfig builds.

   Arnd
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Re: [PATCH] [RFC] qcom_scm: hide Kconfig symbol

2021-09-29 Thread Will Deacon
On Mon, Sep 27, 2021 at 05:22:13PM +0200, Arnd Bergmann wrote:
> From: Arnd Bergmann 
> 
> Now that SCM can be a loadable module, we have to add another
> dependency to avoid link failures when ipa or adreno-gpu are
> built-in:
> 
> aarch64-linux-ld: drivers/net/ipa/ipa_main.o: in function `ipa_probe':
> ipa_main.c:(.text+0xfc4): undefined reference to `qcom_scm_is_available'
> 
> ld.lld: error: undefined symbol: qcom_scm_is_available
> >>> referenced by adreno_gpu.c
> >>>   gpu/drm/msm/adreno/adreno_gpu.o:(adreno_zap_shader_load) in 
> >>> archive drivers/built-in.a
> 
> This can happen when CONFIG_ARCH_QCOM is disabled and we don't select
> QCOM_MDT_LOADER, but some other module selects QCOM_SCM. Ideally we'd
> use a similar dependency here to what we have for QCOM_RPROC_COMMON,
> but that causes dependency loops from other things selecting QCOM_SCM.
> 
> This appears to be an endless problem, so try something different this
> time:
> 
>  - CONFIG_QCOM_SCM becomes a hidden symbol that nothing 'depends on'
>but that is simply selected by all of its users
> 
>  - All the stubs in include/linux/qcom_scm.h can go away
> 
>  - arm-smccc.h needs to provide a stub for __arm_smccc_smc() to
>allow compile-testing QCOM_SCM on all architectures.
> 
>  - To avoid a circular dependency chain involving RESET_CONTROLLER
>and PINCTRL_SUNXI, change the 'depends on RESET_CONTROLLER' in
>the latter one to 'select'.
> 
> The last bit is rather annoying, as drivers should generally never
> 'select' another subsystem, and about half the users of the reset
> controller interface do this anyway.
> 
> Nevertheless, this version seems to pass all my randconfig tests
> and is more robust than any of the prior versions.
> 
> Comments?
> 
> Signed-off-by: Arnd Bergmann 
> ---
>  drivers/firmware/Kconfig|  4 +-
>  drivers/gpu/drm/msm/Kconfig |  4 +-
>  drivers/iommu/Kconfig   |  2 +-
>  drivers/media/platform/Kconfig  |  2 +-
>  drivers/mmc/host/Kconfig|  2 +-
>  drivers/net/ipa/Kconfig |  1 +
>  drivers/net/wireless/ath/ath10k/Kconfig |  2 +-
>  drivers/pinctrl/qcom/Kconfig|  3 +-
>  drivers/pinctrl/sunxi/Kconfig   |  6 +--
>  include/linux/arm-smccc.h   | 10 
>  include/linux/qcom_scm.h| 71 -
>  11 files changed, 23 insertions(+), 84 deletions(-)
> 
> diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
> index 220a58cf0a44..f7dd82ef0b9c 100644
> --- a/drivers/firmware/Kconfig
> +++ b/drivers/firmware/Kconfig
> @@ -203,9 +203,7 @@ config INTEL_STRATIX10_RSU
> Say Y here if you want Intel RSU support.
>  
>  config QCOM_SCM
> - tristate "Qcom SCM driver"
> - depends on ARM || ARM64
> - depends on HAVE_ARM_SMCCC
> + tristate
>   select RESET_CONTROLLER
>  
>  config QCOM_SCM_DOWNLOAD_MODE_DEFAULT
> diff --git a/drivers/gpu/drm/msm/Kconfig b/drivers/gpu/drm/msm/Kconfig
> index e9c6af78b1d7..3ddf739a6f9b 100644
> --- a/drivers/gpu/drm/msm/Kconfig
> +++ b/drivers/gpu/drm/msm/Kconfig
> @@ -17,7 +17,7 @@ config DRM_MSM
>   select DRM_SCHED
>   select SHMEM
>   select TMPFS
> - select QCOM_SCM if ARCH_QCOM
> + select QCOM_SCM
>   select WANT_DEV_COREDUMP
>   select SND_SOC_HDMI_CODEC if SND_SOC
>   select SYNC_FILE
> @@ -55,7 +55,7 @@ config DRM_MSM_GPU_SUDO
>  
>  config DRM_MSM_HDMI_HDCP
>   bool "Enable HDMI HDCP support in MSM DRM driver"
> - depends on DRM_MSM && QCOM_SCM
> + depends on DRM_MSM
>   default y
>   help
> Choose this option to enable HDCP state machine
> diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
> index 124c41adeca1..989c83acbfee 100644
> --- a/drivers/iommu/Kconfig
> +++ b/drivers/iommu/Kconfig
> @@ -308,7 +308,7 @@ config APPLE_DART
>  config ARM_SMMU
>   tristate "ARM Ltd. System MMU (SMMU) Support"
>   depends on ARM64 || ARM || (COMPILE_TEST && !GENERIC_ATOMIC64)
> - depends on QCOM_SCM || !QCOM_SCM #if QCOM_SCM=m this can't be =y
> + select QCOM_SCM
>   select IOMMU_API
>   select IOMMU_IO_PGTABLE_LPAE
>   select ARM_DMA_USE_IOMMU if ARM

I don't want to get in the way of this patch because I'm also tired of the
randconfig failures caused by QCOM_SCM. However, ARM_SMMU is applicable to
a wide variety of (non-qcom) SoCs and so it seems a shame to require the
QCOM_SCM code to be included for all of those when it's not strictly needed
at all.

Will
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Re: [PATCH] [RFC] qcom_scm: hide Kconfig symbol

2021-09-28 Thread Arnd Bergmann
On Tue, Sep 28, 2021 at 9:05 AM Kalle Valo  wrote:
> Arnd Bergmann  writes:
> > From: Arnd Bergmann 
> I assume I can continue to build test ATH10K_SNOC with x86 as before?
> That's important for me. If yes, then:
>
> Acked-by: Kalle Valo 
>
> --
> https://patchwork.kernel.org/project/linux-wireless/list/
>
> https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches

Yes, the difference is that this will then also build the qcom_scm module, but
that should not cause any problems after the other changes in this patch.

  Arnd
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Re: [PATCH] [RFC] qcom_scm: hide Kconfig symbol

2021-09-28 Thread Kalle Valo
Arnd Bergmann  writes:

> From: Arnd Bergmann 
>
> Now that SCM can be a loadable module, we have to add another
> dependency to avoid link failures when ipa or adreno-gpu are
> built-in:
>
> aarch64-linux-ld: drivers/net/ipa/ipa_main.o: in function `ipa_probe':
> ipa_main.c:(.text+0xfc4): undefined reference to `qcom_scm_is_available'
>
> ld.lld: error: undefined symbol: qcom_scm_is_available
 referenced by adreno_gpu.c
   gpu/drm/msm/adreno/adreno_gpu.o:(adreno_zap_shader_load)
 in archive drivers/built-in.a
>
> This can happen when CONFIG_ARCH_QCOM is disabled and we don't select
> QCOM_MDT_LOADER, but some other module selects QCOM_SCM. Ideally we'd
> use a similar dependency here to what we have for QCOM_RPROC_COMMON,
> but that causes dependency loops from other things selecting QCOM_SCM.
>
> This appears to be an endless problem, so try something different this
> time:
>
>  - CONFIG_QCOM_SCM becomes a hidden symbol that nothing 'depends on'
>but that is simply selected by all of its users
>
>  - All the stubs in include/linux/qcom_scm.h can go away
>
>  - arm-smccc.h needs to provide a stub for __arm_smccc_smc() to
>allow compile-testing QCOM_SCM on all architectures.
>
>  - To avoid a circular dependency chain involving RESET_CONTROLLER
>and PINCTRL_SUNXI, change the 'depends on RESET_CONTROLLER' in
>the latter one to 'select'.
>
> The last bit is rather annoying, as drivers should generally never
> 'select' another subsystem, and about half the users of the reset
> controller interface do this anyway.
>
> Nevertheless, this version seems to pass all my randconfig tests
> and is more robust than any of the prior versions.
>
> Comments?
>
> Signed-off-by: Arnd Bergmann 

[...]

> diff --git a/drivers/net/wireless/ath/ath10k/Kconfig 
> b/drivers/net/wireless/ath/ath10k/Kconfig
> index 741289e385d5..ca007b800f75 100644
> --- a/drivers/net/wireless/ath/ath10k/Kconfig
> +++ b/drivers/net/wireless/ath/ath10k/Kconfig
> @@ -44,7 +44,7 @@ config ATH10K_SNOC
>   tristate "Qualcomm ath10k SNOC support"
>   depends on ATH10K
>   depends on ARCH_QCOM || COMPILE_TEST
> - depends on QCOM_SCM || !QCOM_SCM #if QCOM_SCM=m this can't be =y
> + select QCOM_SCM
>   select QCOM_QMI_HELPERS
>   help
> This module adds support for integrated WCN3990 chip connected

I assume I can continue to build test ATH10K_SNOC with x86 as before?
That's important for me. If yes, then:

Acked-by: Kalle Valo 

-- 
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https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
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Re: [PATCH] [RFC] qcom_scm: hide Kconfig symbol

2021-09-27 Thread Arnd Bergmann
On Mon, Sep 27, 2021 at 10:42 PM Bjorn Andersson
 wrote:
> On Mon 27 Sep 13:15 PDT 2021, Arnd Bergmann wrote:
> > On Mon, Sep 27, 2021 at 9:52 PM Bjorn Andersson 
> >  wrote:
> >
> > An easier option might be to find a way to build QCOM_SCM without
> > RESET_CONTROLLER for compile testing purposes. I don't know
> > what would break from that.
> >
>
> Afaict the reset API is properly stubbed and RESET_CONTROLLER is a bool,
> so I think we can simply drop the "select" and the kernel will still
> compile fine in all combinations.
>
> When it comes to runtime, we currently select RESET_CONTROLLER from the
> Qualcomm common clocks. If that is dropped (why would it...) it seems
> possible to build a custom kernel for msm8916 that we can boot and miss
> the stubbed out "mss restart" reset line from the SCM.
>
>
> So, let's just drop the select RESET_CONTROLLER from SCM for now.

Ok, I've made that change locally, giving it more time on the randconfig
build box now.

   Arnd
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Re: [PATCH] [RFC] qcom_scm: hide Kconfig symbol

2021-09-27 Thread Bjorn Andersson
On Mon 27 Sep 13:15 PDT 2021, Arnd Bergmann wrote:

> On Mon, Sep 27, 2021 at 9:52 PM Bjorn Andersson
>  wrote:
> > On Mon 27 Sep 08:22 PDT 2021, Arnd Bergmann wrote:
> > > From: Arnd Bergmann 
> > >
> > >  - To avoid a circular dependency chain involving RESET_CONTROLLER
> > >and PINCTRL_SUNXI, change the 'depends on RESET_CONTROLLER' in
> > >the latter one to 'select'.
> >
> > Can you please help me understand why this is part of the same patch?
> 
> This can be done as a preparatory patch if we decide to do it this way,
> for the review it seemed better to spell out that this is required.
> 
> I still hope that we can avoid adding another 'select RESET_CONTROLLER'
> if someone can figure out what to do instead.
> 

Okay, thanks.

> The problem here is that QCOM_SCM selects RESET_CONTROLLER,
> and turning that into 'depends on' would in turn mean that any driver that
> wants to select QCOM_SCM would have to have the same RESET_CONTROLLER
> dependency.
> 

Right, and that will just be another thing we'll get wrong across the
tree.

> An easier option might be to find a way to build QCOM_SCM without
> RESET_CONTROLLER for compile testing purposes. I don't know
> what would break from that.
> 

Afaict the reset API is properly stubbed and RESET_CONTROLLER is a bool,
so I think we can simply drop the "select" and the kernel will still
compile fine in all combinations.

When it comes to runtime, we currently select RESET_CONTROLLER from the
Qualcomm common clocks. If that is dropped (why would it...) it seems
possible to build a custom kernel for msm8916 that we can boot and miss
the stubbed out "mss restart" reset line from the SCM.


So, let's just drop the select RESET_CONTROLLER from SCM for now.

Regards,
Bjorn
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Re: [PATCH] [RFC] qcom_scm: hide Kconfig symbol

2021-09-27 Thread Arnd Bergmann
On Mon, Sep 27, 2021 at 9:52 PM Bjorn Andersson
 wrote:
> On Mon 27 Sep 08:22 PDT 2021, Arnd Bergmann wrote:
> > From: Arnd Bergmann 
> >
> >  - To avoid a circular dependency chain involving RESET_CONTROLLER
> >and PINCTRL_SUNXI, change the 'depends on RESET_CONTROLLER' in
> >the latter one to 'select'.
>
> Can you please help me understand why this is part of the same patch?

This can be done as a preparatory patch if we decide to do it this way,
for the review it seemed better to spell out that this is required.

I still hope that we can avoid adding another 'select RESET_CONTROLLER'
if someone can figure out what to do instead.

The problem here is that QCOM_SCM selects RESET_CONTROLLER,
and turning that into 'depends on' would in turn mean that any driver that
wants to select QCOM_SCM would have to have the same RESET_CONTROLLER
dependency.

An easier option might be to find a way to build QCOM_SCM without
RESET_CONTROLLER for compile testing purposes. I don't know
what would break from that.

 Arnd
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Re: [PATCH] [RFC] qcom_scm: hide Kconfig symbol

2021-09-27 Thread Bjorn Andersson
On Mon 27 Sep 08:22 PDT 2021, Arnd Bergmann wrote:

> From: Arnd Bergmann 
> 
> Now that SCM can be a loadable module, we have to add another
> dependency to avoid link failures when ipa or adreno-gpu are
> built-in:
> 
> aarch64-linux-ld: drivers/net/ipa/ipa_main.o: in function `ipa_probe':
> ipa_main.c:(.text+0xfc4): undefined reference to `qcom_scm_is_available'
> 
> ld.lld: error: undefined symbol: qcom_scm_is_available
> >>> referenced by adreno_gpu.c
> >>>   gpu/drm/msm/adreno/adreno_gpu.o:(adreno_zap_shader_load) in 
> >>> archive drivers/built-in.a
> 
> This can happen when CONFIG_ARCH_QCOM is disabled and we don't select
> QCOM_MDT_LOADER, but some other module selects QCOM_SCM. Ideally we'd
> use a similar dependency here to what we have for QCOM_RPROC_COMMON,
> but that causes dependency loops from other things selecting QCOM_SCM.
> 
> This appears to be an endless problem, so try something different this
> time:
> 
>  - CONFIG_QCOM_SCM becomes a hidden symbol that nothing 'depends on'
>but that is simply selected by all of its users
> 
>  - All the stubs in include/linux/qcom_scm.h can go away
> 
>  - arm-smccc.h needs to provide a stub for __arm_smccc_smc() to
>allow compile-testing QCOM_SCM on all architectures.
> 
>  - To avoid a circular dependency chain involving RESET_CONTROLLER
>and PINCTRL_SUNXI, change the 'depends on RESET_CONTROLLER' in
>the latter one to 'select'.

Can you please help me understand why this is part of the same patch?

> 
> The last bit is rather annoying, as drivers should generally never
> 'select' another subsystem, and about half the users of the reset
> controller interface do this anyway.
> 
> Nevertheless, this version seems to pass all my randconfig tests
> and is more robust than any of the prior versions.
> 
> Comments?
> 

I like it!

It's less confusing than the current scheme, so should be easier to
get right. And I like the fact that we don't need the stubs anymore.


@John, could you please have a look at this as well, wrt GKI.

Regards,
Bjorn

> Signed-off-by: Arnd Bergmann 
> ---
>  drivers/firmware/Kconfig|  4 +-
>  drivers/gpu/drm/msm/Kconfig |  4 +-
>  drivers/iommu/Kconfig   |  2 +-
>  drivers/media/platform/Kconfig  |  2 +-
>  drivers/mmc/host/Kconfig|  2 +-
>  drivers/net/ipa/Kconfig |  1 +
>  drivers/net/wireless/ath/ath10k/Kconfig |  2 +-
>  drivers/pinctrl/qcom/Kconfig|  3 +-
>  drivers/pinctrl/sunxi/Kconfig   |  6 +--
>  include/linux/arm-smccc.h   | 10 
>  include/linux/qcom_scm.h| 71 -
>  11 files changed, 23 insertions(+), 84 deletions(-)
> 
> diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
> index 220a58cf0a44..f7dd82ef0b9c 100644
> --- a/drivers/firmware/Kconfig
> +++ b/drivers/firmware/Kconfig
> @@ -203,9 +203,7 @@ config INTEL_STRATIX10_RSU
> Say Y here if you want Intel RSU support.
>  
>  config QCOM_SCM
> - tristate "Qcom SCM driver"
> - depends on ARM || ARM64
> - depends on HAVE_ARM_SMCCC
> + tristate
>   select RESET_CONTROLLER
>  
>  config QCOM_SCM_DOWNLOAD_MODE_DEFAULT
> diff --git a/drivers/gpu/drm/msm/Kconfig b/drivers/gpu/drm/msm/Kconfig
> index e9c6af78b1d7..3ddf739a6f9b 100644
> --- a/drivers/gpu/drm/msm/Kconfig
> +++ b/drivers/gpu/drm/msm/Kconfig
> @@ -17,7 +17,7 @@ config DRM_MSM
>   select DRM_SCHED
>   select SHMEM
>   select TMPFS
> - select QCOM_SCM if ARCH_QCOM
> + select QCOM_SCM
>   select WANT_DEV_COREDUMP
>   select SND_SOC_HDMI_CODEC if SND_SOC
>   select SYNC_FILE
> @@ -55,7 +55,7 @@ config DRM_MSM_GPU_SUDO
>  
>  config DRM_MSM_HDMI_HDCP
>   bool "Enable HDMI HDCP support in MSM DRM driver"
> - depends on DRM_MSM && QCOM_SCM
> + depends on DRM_MSM
>   default y
>   help
> Choose this option to enable HDCP state machine
> diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
> index 124c41adeca1..989c83acbfee 100644
> --- a/drivers/iommu/Kconfig
> +++ b/drivers/iommu/Kconfig
> @@ -308,7 +308,7 @@ config APPLE_DART
>  config ARM_SMMU
>   tristate "ARM Ltd. System MMU (SMMU) Support"
>   depends on ARM64 || ARM || (COMPILE_TEST && !GENERIC_ATOMIC64)
> - depends on QCOM_SCM || !QCOM_SCM #if QCOM_SCM=m this can't be =y
> + select QCOM_SCM
>   select IOMMU_API
>   select IOMMU_IO_PGTABLE_LPAE
>   select ARM_DMA_USE_IOMMU if ARM
> diff --git a/drivers/media/platform/Kconfig b/drivers/media/platform/Kconfig
> index 157c924686e4..80321e03809a 100644
> --- a/drivers/media/platform/Kconfig
> +++ b/drivers/media/platform/Kconfig
> @@ -565,7 +565,7 @@ config VIDEO_QCOM_VENUS
>   depends on VIDEO_DEV && VIDEO_V4L2 && QCOM_SMEM
>   depends on (ARCH_QCOM && IOMMU_DMA) || COMPILE_TEST
>   select QCOM_MDT_LOADER if ARCH_QCOM
> - select QCOM_SCM if ARCH_QCOM
> + select QCOM_SCM
>