From: Thierry Reding <treding@xxxxxxxxxx>
The ARM_DMA_USE_IOMMU Kconfig option has side-effects that drivers can
not opt into but have to explicitly opt out of. This can lead to subtle
bugs that are difficult to track down and not immediately obvious to be
related to this Kconfig option.
To avoid this confusion, always enable the option to expose any lurking
bugs once and allow any regressions introduced by the DMA/IOMMU code to
be caught more quickly in the future.
Note that some drivers still use the Kconfig symbol to provide different
code paths depending on what architecture the code runs on (e.g. 32-bit
ARM vs. 64-bit ARM which have different and incompatible implementations
of the DMA/IOMMU integration code), so leave the symbol in place to keep
those drivers working.
For the long term, it is preferable to transition everyone to the
generic DMA/IOMMU integration code in drivers/iommu/dma-iommu.c.
Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
---
Changes in v2:
- new patch
arch/arm/Kconfig | 2 +-
arch/arm/include/asm/device.h | 6 ------
arch/arm/mm/dma-mapping.c | 18 ------------------
drivers/iommu/Kconfig | 7 -------
drivers/media/platform/Kconfig | 1 -
5 files changed, 1 insertion(+), 33 deletions(-)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index fa0b190f8a38..3c91de78535a 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -124,7 +124,7 @@ config NEED_SG_DMA_LENGTH
bool
config ARM_DMA_USE_IOMMU
- bool
+ def_bool y
select ARM_HAS_SG_CHAIN
select NEED_SG_DMA_LENGTH
diff --git a/arch/arm/include/asm/device.h b/arch/arm/include/asm/device.h
index 3234fe9bba6e..c3cf38e16866 100644
--- a/arch/arm/include/asm/device.h
+++ b/arch/arm/include/asm/device.h
@@ -13,9 +13,7 @@ struct dev_archdata {
#ifdef CONFIG_IOMMU_API
void *iommu; /* private IOMMU data */
#endif
-#ifdef CONFIG_ARM_DMA_USE_IOMMU
struct dma_iommu_mapping *mapping;
-#endif
#ifdef CONFIG_XEN
const struct dma_map_ops *dev_dma_ops;
#endif
@@ -31,10 +29,6 @@ struct pdev_archdata {
#endif
};
-#ifdef CONFIG_ARM_DMA_USE_IOMMU
#define to_dma_iommu_mapping(dev) ((dev)->archdata.mapping)
-#else
-#define to_dma_iommu_mapping(dev) NULL
-#endif
#endif
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index cc63a25bd088..f6c28ed5651a 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -1174,8 +1174,6 @@ static int __init dma_debug_do_init(void)
}
core_initcall(dma_debug_do_init);
-#ifdef CONFIG_ARM_DMA_USE_IOMMU
-
static int __dma_info_to_prot(enum dma_data_direction dir, unsigned long attrs)
{
int prot = 0;
@@ -2366,20 +2364,6 @@ static void arm_teardown_iommu_dma_ops(struct device *dev)
arm_iommu_release_mapping(mapping);
}
-#else
-
-static bool arm_setup_iommu_dma_ops(struct device *dev, u64 dma_base, u64 size,
- const struct iommu_ops *iommu)
-{
- return false;
-}
-
-static void arm_teardown_iommu_dma_ops(struct device *dev) { }
-
-#define arm_get_iommu_dma_map_ops arm_get_dma_map_ops
-
-#endif /* CONFIG_ARM_DMA_USE_IOMMU */
-
static const struct dma_map_ops *arm_get_dma_map_ops(bool coherent)
{
return coherent ? &arm_coherent_dma_ops : &arm_dma_ops;
@@ -2426,7 +2410,6 @@ void arch_teardown_dma_ops(struct device *dev)
void arch_iommu_detach_device(struct device *dev)
{
-#ifdef CONFIG_ARM_DMA_USE_IOMMU
struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
const struct dma_map_ops *dma_ops;
@@ -2438,5 +2421,4 @@ void arch_iommu_detach_device(struct device *dev)
dma_ops = arm_get_dma_map_ops(dev->archdata.dma_coherent);
set_dma_ops(dev, dma_ops);
-#endif
}
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index df171cb85822..7f0b3ca76a17 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -226,7 +226,6 @@ config ROCKCHIP_IOMMU
depends on ARM || ARM64
depends on ARCH_ROCKCHIP || COMPILE_TEST
select IOMMU_API
- select ARM_DMA_USE_IOMMU
help
Support for IOMMUs found on Rockchip rk32xx SOCs.
These IOMMUs allow virtualization of the address space used by most
@@ -259,7 +258,6 @@ config EXYNOS_IOMMU
depends on ARCH_EXYNOS && MMU
depends on !CPU_BIG_ENDIAN # revisit driver if we can enable big-endian ptes
select IOMMU_API
- select ARM_DMA_USE_IOMMU
help
Support for the IOMMU (System MMU) of Samsung Exynos application
processor family. This enables H/W multimedia accelerators to see
@@ -283,7 +281,6 @@ config IPMMU_VMSA
depends on ARCH_RENESAS || (COMPILE_TEST && !GENERIC_ATOMIC64)
select IOMMU_API
select IOMMU_IO_PGTABLE_LPAE
- select ARM_DMA_USE_IOMMU
help
Support for the Renesas VMSA-compatible IPMMU Renesas found in the
R-Mobile APE6 and R-Car H2/M2 SoCs.
@@ -304,7 +301,6 @@ config ARM_SMMU
depends on (ARM64 || ARM) && MMU
select IOMMU_API
select IOMMU_IO_PGTABLE_LPAE
- select ARM_DMA_USE_IOMMU if ARM
help
Support for implementations of the ARM System MMU architecture
versions 1 and 2.
@@ -344,7 +340,6 @@ config MTK_IOMMU
bool "MTK IOMMU Support"
depends on ARM || ARM64
depends on ARCH_MEDIATEK || COMPILE_TEST
- select ARM_DMA_USE_IOMMU
select IOMMU_API
select IOMMU_DMA
select IOMMU_IO_PGTABLE_ARMV7S
@@ -361,7 +356,6 @@ config MTK_IOMMU_V1
bool "MTK IOMMU Version 1 (M4U gen1) Support"
depends on ARM
depends on ARCH_MEDIATEK || COMPILE_TEST
- select ARM_DMA_USE_IOMMU
select IOMMU_API
select MEMORY
select MTK_SMI
@@ -379,7 +373,6 @@ config QCOM_IOMMU
depends on HAS_DMA
select IOMMU_API
select IOMMU_IO_PGTABLE_LPAE
- select ARM_DMA_USE_IOMMU
help
Support for IOMMU on certain Qualcomm SoCs.
diff --git a/drivers/media/platform/Kconfig b/drivers/media/platform/Kconfig
index e3229f7baed1..5f7135b052ed 100644
--- a/drivers/media/platform/Kconfig
+++ b/drivers/media/platform/Kconfig
@@ -66,7 +66,6 @@ config VIDEO_OMAP3
depends on (ARCH_OMAP3 && OMAP_IOMMU) || COMPILE_TEST
depends on COMMON_CLK
depends on HAS_DMA && OF
- select ARM_DMA_USE_IOMMU if OMAP_IOMMU
select VIDEOBUF2_DMA_CONTIG
select MFD_SYSCON
select V4L2_FWNODE
--
2.17.0
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