Re: [RFC][PATCH 5/5] firmware: QCOM_SCM: Allow qcom_scm driver to be loadable as a permenent module
On 03-07-20, 13:23, Will Deacon wrote: > On Tue, Jun 16, 2020 at 01:52:32PM -0700, John Stultz wrote: > > On Tue, Jun 16, 2020 at 12:55 AM Marc Zyngier 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? So drivers deal with this by making rules in Kconfig which will prohibit this case. QCOM_SCM depends on ARM_SMMU with the caveat that if ARM_SMMU is a module, QCOM_SCM cant be inbuilt. This can be done by adding below line in Kconfig for QCOM_SCM: depends on ARM_SMMU || !ARM_SMMU This is quite prevalent is drivers to ensure dependency like this Thanks -- ~Vinod ___ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
Re: [RFC][PATCH 5/5] firmware: QCOM_SCM: Allow qcom_scm driver to be loadable as a permenent module
On Tue, Jun 16, 2020 at 01:52:32PM -0700, John Stultz wrote: > On Tue, Jun 16, 2020 at 12:55 AM Marc Zyngier 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
Re: [RFC][PATCH 5/5] firmware: QCOM_SCM: Allow qcom_scm driver to be loadable as a permenent module
Hi John,
+Will for the SMMU part.
On 2020-06-16 07:13, John Stultz wrote:
Allow the qcom_scm driver to be loadable as a
permenent module.
Cc: Andy Gross
Cc: Bjorn Andersson
Cc: Joerg Roedel
Cc: Thomas Gleixner
Cc: Jason Cooper
Cc: Marc Zyngier
Cc: Linus Walleij
Cc: Lina Iyer
Cc: Saravana Kannan
Cc: Todd Kjos
Cc: Greg Kroah-Hartman
Cc: linux-arm-...@vger.kernel.org
Cc: iommu@lists.linux-foundation.org
Cc: linux-g...@vger.kernel.org
Signed-off-by: John Stultz
---
drivers/firmware/Kconfig| 2 +-
drivers/firmware/Makefile | 3 ++-
drivers/firmware/qcom_scm.c | 4
drivers/iommu/Kconfig | 2 ++
4 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
index fbd785dd0513..9e533a462bf4 100644
--- a/drivers/firmware/Kconfig
+++ b/drivers/firmware/Kconfig
@@ -236,7 +236,7 @@ config INTEL_STRATIX10_RSU
Say Y here if you want Intel RSU support.
config QCOM_SCM
- bool
+ tristate "Qcom SCM driver"
depends on ARM || ARM64
select RESET_CONTROLLER
diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile
index 99510be9f5ed..cf24d674216b 100644
--- a/drivers/firmware/Makefile
+++ b/drivers/firmware/Makefile
@@ -17,7 +17,8 @@ obj-$(CONFIG_ISCSI_IBFT) += iscsi_ibft.o
obj-$(CONFIG_FIRMWARE_MEMMAP) += memmap.o
obj-$(CONFIG_RASPBERRYPI_FIRMWARE) += raspberrypi.o
obj-$(CONFIG_FW_CFG_SYSFS) += qemu_fw_cfg.o
-obj-$(CONFIG_QCOM_SCM) += qcom_scm.o qcom_scm-smc.o qcom_scm-legacy.o
+obj-$(CONFIG_QCOM_SCM) += qcom-scm.o
+qcom-scm-objs += qcom_scm.o qcom_scm-smc.o qcom_scm-legacy.o
obj-$(CONFIG_TI_SCI_PROTOCOL) += ti_sci.o
obj-$(CONFIG_TRUSTED_FOUNDATIONS) += trusted_foundations.o
obj-$(CONFIG_TURRIS_MOX_RWTM) += turris-mox-rwtm.o
diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
index 0e7233a20f34..b5e88bf66975 100644
--- a/drivers/firmware/qcom_scm.c
+++ b/drivers/firmware/qcom_scm.c
@@ -1155,6 +1155,7 @@ static const struct of_device_id
qcom_scm_dt_match[] = {
{ .compatible = "qcom,scm" },
{}
};
+MODULE_DEVICE_TABLE(of, qcom_scm_dt_match);
static struct platform_driver qcom_scm_driver = {
.driver = {
@@ -1170,3 +1171,6 @@ static int __init qcom_scm_init(void)
return platform_driver_register(_scm_driver);
}
subsys_initcall(qcom_scm_init);
+
+MODULE_DESCRIPTION("Qualcomm Technologies, Inc. SCM driver");
+MODULE_LICENSE("GPL v2");
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...
select IOMMU_API
select IOMMU_IO_PGTABLE_LPAE
select ARM_DMA_USE_IOMMU if ARM
@@ -500,6 +501,7 @@ 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 IOMMU_API
select IOMMU_IO_PGTABLE_LPAE
select ARM_DMA_USE_IOMMU
Thanks,
M.
--
Jazz is not dead. It just smells funny...
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