The newly added Mediatek IOMMU driver uses the IOMMU_DMA infrastructure,
but unlike other such drivers, it does not select 'ARM_DMA_USE_IOMMU',
which is a prerequisite, leading to a link error:
warning: (MTK_IOMMU) selects IOMMU_DMA which has unmet direct dependencies (IOMMU_SUPPORT && NEED_SG_DMA_LENGTH)
drivers/iommu/built-in.o: In function `iommu_put_dma_cookie':
mtk_iommu.c:(.text+0x11fe): undefined reference to `put_iova_domain'
drivers/iommu/built-in.o: In function `iommu_dma_init_domain':
mtk_iommu.c:(.text+0x1316): undefined reference to `init_iova_domain'
drivers/iommu/built-in.o: In function `__iommu_dma_unmap':
mtk_iommu.c:(.text+0x1380): undefined reference to `find_iova'
This adds the same select that the other drivers have. On a related
note, I wonder if we should just always select ARM_DMA_USE_IOMMU
whenever any IOMMU driver is enabled. Are there any cases where
we would enable an IOMMU but not use it?
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 0df4fabe208d ("iommu/mediatek: Add mt8173 IOMMU driver")
---
drivers/iommu/Kconfig | 1 +
1 file changed, 1 insertion(+)
When CONFIG_PM is unset, we get a harmless warning for this driver:
drivers/iommu/mtk_iommu.c:665:12: error: 'mtk_iommu_suspend' defined but not used [-Werror=unused-function]
drivers/iommu/mtk_iommu.c:680:12: error: 'mtk_iommu_resume' defined but not used [-Werror=unused-function]
Marking the functions as __maybe_unused gits rid of the two functions
and lets the compiler silently drop the object code, while still
doing syntax checking on them for build-time verification.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 0df4fabe208d ("iommu/mediatek: Add mt8173 IOMMU driver")
---
drivers/iommu/mtk_iommu.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
On Mon, 2016-02-29 at 10:19 +0100, Arnd Bergmann wrote:
When CONFIG_PM is unset, we get a harmless warning for this driver:
drivers/iommu/mtk_iommu.c:665:12: error: 'mtk_iommu_suspend' defined but not used [-Werror=unused-function]
drivers/iommu/mtk_iommu.c:680:12: error: 'mtk_iommu_resume' defined but not used [-Werror=unused-function]
Marking the functions as __maybe_unused gits rid of the two functions
and lets the compiler silently drop the object code, while still
doing syntax checking on them for build-time verification.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 0df4fabe208d ("iommu/mediatek: Add mt8173 IOMMU driver")
From: Robin Murphy <robin.murphy@arm.com> Date: 2016-02-29 10:37:46
Hi Arnd,
On 29/02/16 09:19, Arnd Bergmann wrote:
The newly added Mediatek IOMMU driver uses the IOMMU_DMA infrastructure,
but unlike other such drivers, it does not select 'ARM_DMA_USE_IOMMU',
which is a prerequisite, leading to a link error:
warning: (MTK_IOMMU) selects IOMMU_DMA which has unmet direct dependencies (IOMMU_SUPPORT && NEED_SG_DMA_LENGTH)
Going off on a tangent, is it actually right for that to depend on a
NEED_* symbol, or should that really be a select instead?
drivers/iommu/built-in.o: In function `iommu_put_dma_cookie':
mtk_iommu.c:(.text+0x11fe): undefined reference to `put_iova_domain'
drivers/iommu/built-in.o: In function `iommu_dma_init_domain':
mtk_iommu.c:(.text+0x1316): undefined reference to `init_iova_domain'
drivers/iommu/built-in.o: In function `__iommu_dma_unmap':
mtk_iommu.c:(.text+0x1380): undefined reference to `find_iova'
This adds the same select that the other drivers have. On a related
note, I wonder if we should just always select ARM_DMA_USE_IOMMU
whenever any IOMMU driver is enabled. Are there any cases where
we would enable an IOMMU but not use it?
You could use one solely for VFIO without caring about DMA ops - I think
that's mostly how ARM SMMUs are being used in practice at the moment -
but DMA-focused 'media' IOMMUs vastly outnumber 'virtualisation' IOMMUs
on ARM, so it would probably make sense. We already have the equivalent
"select IOMMU_DMA if IOMMU_SUPPORT" on arm64.
If going down this route, I'd be inclined to add an "if ARM" there, just
for clarity.
select IOMMU_API
select IOMMU_DMA
As above, this is already selected on arm64, and isn't used on 32-bit*,
so could probably just be removed, especially if it leads to build issues.
Robin.
*yet, of course. I need to have a proper look over Marek's RFC ;)
On Monday 29 February 2016 10:37:40 Robin Murphy wrote:
Hi Arnd,
On 29/02/16 09:19, Arnd Bergmann wrote:
quoted
The newly added Mediatek IOMMU driver uses the IOMMU_DMA infrastructure,
but unlike other such drivers, it does not select 'ARM_DMA_USE_IOMMU',
which is a prerequisite, leading to a link error:
warning: (MTK_IOMMU) selects IOMMU_DMA which has unmet direct dependencies (IOMMU_SUPPORT && NEED_SG_DMA_LENGTH)
Going off on a tangent, is it actually right for that to depend on a
NEED_* symbol, or should that really be a select instead?
ARM_DMA_USE_IOMMU gets this right, it selects NEED_SG_DMA_LENGTH as it
actually needs it.
The IOMMU_DMA symbol is a bit strange, and the dependency can probably
get dropped altogether, but at least here it told us what went wrong.
quoted
drivers/iommu/built-in.o: In function `iommu_put_dma_cookie':
mtk_iommu.c:(.text+0x11fe): undefined reference to `put_iova_domain'
drivers/iommu/built-in.o: In function `iommu_dma_init_domain':
mtk_iommu.c:(.text+0x1316): undefined reference to `init_iova_domain'
drivers/iommu/built-in.o: In function `__iommu_dma_unmap':
mtk_iommu.c:(.text+0x1380): undefined reference to `find_iova'
This adds the same select that the other drivers have. On a related
note, I wonder if we should just always select ARM_DMA_USE_IOMMU
whenever any IOMMU driver is enabled. Are there any cases where
we would enable an IOMMU but not use it?
You could use one solely for VFIO without caring about DMA ops - I think
that's mostly how ARM SMMUs are being used in practice at the moment -
but DMA-focused 'media' IOMMUs vastly outnumber 'virtualisation' IOMMUs
on ARM, so it would probably make sense. We already have the equivalent
"select IOMMU_DMA if IOMMU_SUPPORT" on arm64.
From: Robin Murphy <robin.murphy@arm.com> Date: 2016-02-29 11:22:30
On 29/02/16 10:53, Arnd Bergmann wrote:
On Monday 29 February 2016 10:37:40 Robin Murphy wrote:
quoted
Hi Arnd,
On 29/02/16 09:19, Arnd Bergmann wrote:
quoted
The newly added Mediatek IOMMU driver uses the IOMMU_DMA infrastructure,
but unlike other such drivers, it does not select 'ARM_DMA_USE_IOMMU',
which is a prerequisite, leading to a link error:
warning: (MTK_IOMMU) selects IOMMU_DMA which has unmet direct dependencies (IOMMU_SUPPORT && NEED_SG_DMA_LENGTH)
Going off on a tangent, is it actually right for that to depend on a
NEED_* symbol, or should that really be a select instead?
ARM_DMA_USE_IOMMU gets this right, it selects NEED_SG_DMA_LENGTH as it
actually needs it.
The IOMMU_DMA symbol is a bit strange, and the dependency can probably
get dropped altogether, but at least here it told us what went wrong.
IOMMU_DMA uses sg_dma_len() unconditionally all over the place, hence
the "dependency". Thanks for the clarification; fix sent.
quoted
quoted
drivers/iommu/built-in.o: In function `iommu_put_dma_cookie':
mtk_iommu.c:(.text+0x11fe): undefined reference to `put_iova_domain'
drivers/iommu/built-in.o: In function `iommu_dma_init_domain':
mtk_iommu.c:(.text+0x1316): undefined reference to `init_iova_domain'
drivers/iommu/built-in.o: In function `__iommu_dma_unmap':
mtk_iommu.c:(.text+0x1380): undefined reference to `find_iova'
This adds the same select that the other drivers have. On a related
note, I wonder if we should just always select ARM_DMA_USE_IOMMU
whenever any IOMMU driver is enabled. Are there any cases where
we would enable an IOMMU but not use it?
You could use one solely for VFIO without caring about DMA ops - I think
that's mostly how ARM SMMUs are being used in practice at the moment -
but DMA-focused 'media' IOMMUs vastly outnumber 'virtualisation' IOMMUs
on ARM, so it would probably make sense. We already have the equivalent
"select IOMMU_DMA if IOMMU_SUPPORT" on arm64.
If going down this route, I'd be inclined to add an "if ARM" there, just
for clarity.
That would run into the NEED_SG_DMA_LENGTH problem on other architectures
that don't already set it, right?
Sorry, I'm lost - wouldn't "depends on ARM || ARM64" make other
architectures moot? arm64 already has NEED_SG_DMA_LENGTH=y by default.
Nevermind, I didn't notice the dependency on the architecture.
What is keeping us from having 'depends on ARM || ARM64 || COMPILE_TEST'?
I assume it doesn't work yet, but it would be nice to get that done
at some point so we can take advantage of automated build testing like
coverity.
Arnd
If going down this route, I'd be inclined to add an "if ARM" there, just
for clarity.
That would run into the NEED_SG_DMA_LENGTH problem on other architectures
that don't already set it, right?
Sorry, I'm lost - wouldn't "depends on ARM || ARM64" make other
architectures moot? arm64 already has NEED_SG_DMA_LENGTH=y by default.
Nevermind, I didn't notice the dependency on the architecture.
What is keeping us from having 'depends on ARM || ARM64 || COMPILE_TEST'?
IIRC it got changed because the kbuild test robot was consistently
blowing up due to missing definitions on things like parisc.
Robin.
I assume it doesn't work yet, but it would be nice to get that done
at some point so we can take advantage of automated build testing like
coverity.
Arnd
On Mon, Feb 29, 2016 at 10:19:06AM +0100, Arnd Bergmann wrote:
The newly added Mediatek IOMMU driver uses the IOMMU_DMA infrastructure,
but unlike other such drivers, it does not select 'ARM_DMA_USE_IOMMU',
which is a prerequisite, leading to a link error:
warning: (MTK_IOMMU) selects IOMMU_DMA which has unmet direct dependencies (IOMMU_SUPPORT && NEED_SG_DMA_LENGTH)
drivers/iommu/built-in.o: In function `iommu_put_dma_cookie':
mtk_iommu.c:(.text+0x11fe): undefined reference to `put_iova_domain'
drivers/iommu/built-in.o: In function `iommu_dma_init_domain':
mtk_iommu.c:(.text+0x1316): undefined reference to `init_iova_domain'
drivers/iommu/built-in.o: In function `__iommu_dma_unmap':
mtk_iommu.c:(.text+0x1380): undefined reference to `find_iova'
This adds the same select that the other drivers have. On a related
note, I wonder if we should just always select ARM_DMA_USE_IOMMU
whenever any IOMMU driver is enabled. Are there any cases where
we would enable an IOMMU but not use it?
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 0df4fabe208d ("iommu/mediatek: Add mt8173 IOMMU driver")
---
drivers/iommu/Kconfig | 1 +
1 file changed, 1 insertion(+)