From: Paul Kocialkowski <hidden> Date: 2021-01-15 17:59:39
A mechanism was recently introduced for the sunxi architecture where
the DMA offset for specific devices (under the MBUS) is set by a common
driver (sunxi_mbus). This driver calls dma_direct_set_offset to set
the device's dma_range_map manually.
However this information was overwritten by of_dma_configure_id, which
obtains the map from of_dma_get_range (or keeps it NULL when it fails
and the force_dma argument is true, which is the case for platform
devices).
As a result, the dma_range_map was always overwritten and the mechanism
could not correctly take effect.
This adds a check to ensure that no previous DMA range map is
overwritten and prints a warning when the map was already set while
also being available from dt. In this case, the map that was already
set is kept.
Fixes: b4bdc4fbf8d0 ("soc: sunxi: Deal with the MBUS DMA offsets in a central place")
Signed-off-by: Paul Kocialkowski <redacted>
---
drivers/of/device.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
@@ -181,7 +181,14 @@ int of_dma_configure_id(struct device *dev, struct device_node *np,arch_setup_dma_ops(dev,dma_start,size,iommu,coherent);-dev->dma_range_map=map;+if(!dev->dma_range_map){+dev->dma_range_map=map;+}elseif(map){+dev_warn(dev,+"DMA range map was already set, ignoring range map from dt\n");+kfree(map);+}+return0;}EXPORT_SYMBOL_GPL(of_dma_configure_id);
--
2.30.0
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From: Paul Kocialkowski <hidden> Date: 2021-01-15 17:59:39
The DE2 display engine hardware takes physical addresses that do not
need PHYS_BASE subtracted. As a result, they should not be present
on the mbus driver match list. Remove them.
This was tested on the A83T, along with the patch allowing the DMA
range map to be non-NULL and restores a working display.
Fixes: b4bdc4fbf8d0 ("soc: sunxi: Deal with the MBUS DMA offsets in a central place")
Signed-off-by: Paul Kocialkowski <redacted>
---
drivers/soc/sunxi/sunxi_mbus.c | 5 -----
1 file changed, 5 deletions(-)
From: Paul Kocialkowski <hidden> Date: 2021-01-16 17:08:45
Hi Robin,
Le Sat 16 Jan 21, 14:57, Robin Murphy a écrit :
On 2021-01-15 17:58, Paul Kocialkowski wrote:
quoted
A mechanism was recently introduced for the sunxi architecture where
the DMA offset for specific devices (under the MBUS) is set by a common
driver (sunxi_mbus). This driver calls dma_direct_set_offset to set
the device's dma_range_map manually.
However this information was overwritten by of_dma_configure_id, which
obtains the map from of_dma_get_range (or keeps it NULL when it fails
and the force_dma argument is true, which is the case for platform
devices).
As a result, the dma_range_map was always overwritten and the mechanism
could not correctly take effect.
This adds a check to ensure that no previous DMA range map is
overwritten and prints a warning when the map was already set while
also being available from dt. In this case, the map that was already
set is kept.
Hang on, the hard-coded offset is only intended to be installed when there
*isn't* anything described in DT, in which case of_dma_get_range() should
always bail out early without touching it anyway. This sounds like
something's not quite right in the MBUS driver, so I don't think working
around it in core code is really the right thing to do.
That's right, there is no practical case where the two are in conflict.
The problem that I'm solving here is that dev->dma_range_map is *always*
assigned, even when of_dma_get_range bailed and map still is NULL.
This has the effect of always overwriting what the MBUS driver does
(and leaking its memory too).
Do you have a case where one of the relevant devices inherits a "dma-ranges"
via the regular hierarchy without indirecting via an "interconnects"
reference? Currently you're only checking for the latter, so that would be
one way things could go awry (although to be a problem, said "dma-ranges"
would also have to encode something *other* than the appropriate MBUS
offset, which implies an incorrect or at least inaccurately-structured DT as
well).
No, I think things are good in that regard. No messed up dt or anything like
that :)
Cheers,
Paul
Robin.
quoted
Fixes: b4bdc4fbf8d0 ("soc: sunxi: Deal with the MBUS DMA offsets in a central place")
Signed-off-by: Paul Kocialkowski <redacted>
---
drivers/of/device.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
@@ -181,7 +181,14 @@ int of_dma_configure_id(struct device *dev, struct device_node *np,arch_setup_dma_ops(dev,dma_start,size,iommu,coherent);-dev->dma_range_map=map;+if(!dev->dma_range_map){+dev->dma_range_map=map;+}elseif(map){+dev_warn(dev,+"DMA range map was already set, ignoring range map from dt\n");+kfree(map);+}+return0;}EXPORT_SYMBOL_GPL(of_dma_configure_id);
From: Robin Murphy <robin.murphy@arm.com> Date: 2021-01-16 18:03:32
On 2021-01-15 17:58, Paul Kocialkowski wrote:
A mechanism was recently introduced for the sunxi architecture where
the DMA offset for specific devices (under the MBUS) is set by a common
driver (sunxi_mbus). This driver calls dma_direct_set_offset to set
the device's dma_range_map manually.
However this information was overwritten by of_dma_configure_id, which
obtains the map from of_dma_get_range (or keeps it NULL when it fails
and the force_dma argument is true, which is the case for platform
devices).
As a result, the dma_range_map was always overwritten and the mechanism
could not correctly take effect.
This adds a check to ensure that no previous DMA range map is
overwritten and prints a warning when the map was already set while
also being available from dt. In this case, the map that was already
set is kept.
Hang on, the hard-coded offset is only intended to be installed when
there *isn't* anything described in DT, in which case of_dma_get_range()
should always bail out early without touching it anyway. This sounds
like something's not quite right in the MBUS driver, so I don't think
working around it in core code is really the right thing to do.
Do you have a case where one of the relevant devices inherits a
"dma-ranges" via the regular hierarchy without indirecting via an
"interconnects" reference? Currently you're only checking for the
latter, so that would be one way things could go awry (although to be a
problem, said "dma-ranges" would also have to encode something *other*
than the appropriate MBUS offset, which implies an incorrect or at least
inaccurately-structured DT as well).
Robin.
quoted hunk
Fixes: b4bdc4fbf8d0 ("soc: sunxi: Deal with the MBUS DMA offsets in a central place")
Signed-off-by: Paul Kocialkowski <redacted>
---
drivers/of/device.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
@@ -181,7 +181,14 @@ int of_dma_configure_id(struct device *dev, struct device_node *np,arch_setup_dma_ops(dev,dma_start,size,iommu,coherent);-dev->dma_range_map=map;+if(!dev->dma_range_map){+dev->dma_range_map=map;+}elseif(map){+dev_warn(dev,+"DMA range map was already set, ignoring range map from dt\n");+kfree(map);+}+return0;}EXPORT_SYMBOL_GPL(of_dma_configure_id);
From: Robin Murphy <robin.murphy@arm.com> Date: 2021-01-18 13:37:28
On 2021-01-16 17:07, Paul Kocialkowski wrote:
Hi Robin,
Le Sat 16 Jan 21, 14:57, Robin Murphy a écrit :
quoted
On 2021-01-15 17:58, Paul Kocialkowski wrote:
quoted
A mechanism was recently introduced for the sunxi architecture where
the DMA offset for specific devices (under the MBUS) is set by a common
driver (sunxi_mbus). This driver calls dma_direct_set_offset to set
the device's dma_range_map manually.
However this information was overwritten by of_dma_configure_id, which
obtains the map from of_dma_get_range (or keeps it NULL when it fails
and the force_dma argument is true, which is the case for platform
devices).
As a result, the dma_range_map was always overwritten and the mechanism
could not correctly take effect.
This adds a check to ensure that no previous DMA range map is
overwritten and prints a warning when the map was already set while
also being available from dt. In this case, the map that was already
set is kept.
Hang on, the hard-coded offset is only intended to be installed when there
*isn't* anything described in DT, in which case of_dma_get_range() should
always bail out early without touching it anyway. This sounds like
something's not quite right in the MBUS driver, so I don't think working
around it in core code is really the right thing to do.
That's right, there is no practical case where the two are in conflict.
The problem that I'm solving here is that dev->dma_range_map is *always*
assigned, even when of_dma_get_range bailed and map still is NULL.
This has the effect of always overwriting what the MBUS driver does
(and leaking its memory too).
Oh, I should have looked closer at of_dma_configure_id() itself. I was
assuming that b4bdc4fbf8d0 had been tested and at least *could* work,
but apparently not :/
Indeed it seems there was a fundamental oversight in e0d072782c73
("dma-mapping: introduce DMA range map, supplanting dma_pfn_offset"),
equivalent to the same one I previously made myself with bus_dma_mask
and fixed in 6778be4e5209 ("of/device: Really only set bus DMA mask when
appropriate"). I think same simpler fix is the right one for this case
too, i.e. just move the assignment to dev->dma_range_map up under the
"if (!ret)" condition. Assigning it this late - after the IOMMU and arch
setup - looks wrong anyway, even if it isn't currently an issue in
practice (in principle an IOMMU driver *could* start trying to figure
out reserved regions around DMA windows for a device as early as its
.of_xlate callback, even though that's not the intent of the API design).
Luckily dma_range_map hasn't been hooked up in the equivalent ACPI path
yet, so you're off the hook for fixing that too :)
Cheers,
Robin.
quoted
Do you have a case where one of the relevant devices inherits a "dma-ranges"
via the regular hierarchy without indirecting via an "interconnects"
reference? Currently you're only checking for the latter, so that would be
one way things could go awry (although to be a problem, said "dma-ranges"
would also have to encode something *other* than the appropriate MBUS
offset, which implies an incorrect or at least inaccurately-structured DT as
well).
No, I think things are good in that regard. No messed up dt or anything like
that :)
Cheers,
Paul
quoted
Robin.
quoted
Fixes: b4bdc4fbf8d0 ("soc: sunxi: Deal with the MBUS DMA offsets in a central place")
Signed-off-by: Paul Kocialkowski <redacted>
---
drivers/of/device.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
@@ -181,7 +181,14 @@ int of_dma_configure_id(struct device *dev, struct device_node *np,arch_setup_dma_ops(dev,dma_start,size,iommu,coherent);-dev->dma_range_map=map;+if(!dev->dma_range_map){+dev->dma_range_map=map;+}elseif(map){+dev_warn(dev,+"DMA range map was already set, ignoring range map from dt\n");+kfree(map);+}+return0;}EXPORT_SYMBOL_GPL(of_dma_configure_id);
From: Paul Kocialkowski <hidden> Date: 2021-01-19 09:10:05
Hi Robin,
On Mon 18 Jan 21, 13:27, Robin Murphy wrote:
On 2021-01-16 17:07, Paul Kocialkowski wrote:
quoted
Hi Robin,
Le Sat 16 Jan 21, 14:57, Robin Murphy a écrit :
quoted
On 2021-01-15 17:58, Paul Kocialkowski wrote:
quoted
A mechanism was recently introduced for the sunxi architecture where
the DMA offset for specific devices (under the MBUS) is set by a common
driver (sunxi_mbus). This driver calls dma_direct_set_offset to set
the device's dma_range_map manually.
However this information was overwritten by of_dma_configure_id, which
obtains the map from of_dma_get_range (or keeps it NULL when it fails
and the force_dma argument is true, which is the case for platform
devices).
As a result, the dma_range_map was always overwritten and the mechanism
could not correctly take effect.
This adds a check to ensure that no previous DMA range map is
overwritten and prints a warning when the map was already set while
also being available from dt. In this case, the map that was already
set is kept.
Hang on, the hard-coded offset is only intended to be installed when there
*isn't* anything described in DT, in which case of_dma_get_range() should
always bail out early without touching it anyway. This sounds like
something's not quite right in the MBUS driver, so I don't think working
around it in core code is really the right thing to do.
That's right, there is no practical case where the two are in conflict.
The problem that I'm solving here is that dev->dma_range_map is *always*
assigned, even when of_dma_get_range bailed and map still is NULL.
This has the effect of always overwriting what the MBUS driver does
(and leaking its memory too).
Oh, I should have looked closer at of_dma_configure_id() itself. I was
assuming that b4bdc4fbf8d0 had been tested and at least *could* work, but
apparently not :/
Indeed it seems there was a fundamental oversight in e0d072782c73
("dma-mapping: introduce DMA range map, supplanting dma_pfn_offset"),
equivalent to the same one I previously made myself with bus_dma_mask and
fixed in 6778be4e5209 ("of/device: Really only set bus DMA mask when
appropriate"). I think same simpler fix is the right one for this case too,
i.e. just move the assignment to dev->dma_range_map up under the "if (!ret)"
condition. Assigning it this late - after the IOMMU and arch setup - looks
wrong anyway, even if it isn't currently an issue in practice (in principle
an IOMMU driver *could* start trying to figure out reserved regions around
DMA windows for a device as early as its .of_xlate callback, even though
that's not the intent of the API design).
Okay sounds good, I'll resend a patch with the assignment under if (!ret)!
Luckily dma_range_map hasn't been hooked up in the equivalent ACPI path yet,
so you're off the hook for fixing that too :)
Good for me :)
Cheers,
Paul
quoted
quoted
Do you have a case where one of the relevant devices inherits a "dma-ranges"
via the regular hierarchy without indirecting via an "interconnects"
reference? Currently you're only checking for the latter, so that would be
one way things could go awry (although to be a problem, said "dma-ranges"
would also have to encode something *other* than the appropriate MBUS
offset, which implies an incorrect or at least inaccurately-structured DT as
well).
No, I think things are good in that regard. No messed up dt or anything like
that :)
Cheers,
Paul
quoted
Robin.
quoted
Fixes: b4bdc4fbf8d0 ("soc: sunxi: Deal with the MBUS DMA offsets in a central place")
Signed-off-by: Paul Kocialkowski <redacted>
---
drivers/of/device.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
@@ -181,7 +181,14 @@ int of_dma_configure_id(struct device *dev, struct device_node *np,arch_setup_dma_ops(dev,dma_start,size,iommu,coherent);-dev->dma_range_map=map;+if(!dev->dma_range_map){+dev->dma_range_map=map;+}elseif(map){+dev_warn(dev,+"DMA range map was already set, ignoring range map from dt\n");+kfree(map);+}+return0;}EXPORT_SYMBOL_GPL(of_dma_configure_id);
--
Paul Kocialkowski, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com
From: Paul Kocialkowski <hidden> Date: 2021-01-27 13:05:49
Hi,
On Fri 15 Jan 21, 18:58, Paul Kocialkowski wrote:
A mechanism was recently introduced for the sunxi architecture where
the DMA offset for specific devices (under the MBUS) is set by a common
driver (sunxi_mbus). This driver calls dma_direct_set_offset to set
the device's dma_range_map manually.
However this information was overwritten by of_dma_configure_id, which
obtains the map from of_dma_get_range (or keeps it NULL when it fails
and the force_dma argument is true, which is the case for platform
devices).
As a result, the dma_range_map was always overwritten and the mechanism
could not correctly take effect.
This adds a check to ensure that no previous DMA range map is
overwritten and prints a warning when the map was already set while
also being available from dt. In this case, the map that was already
set is kept.
Fixes: b4bdc4fbf8d0 ("soc: sunxi: Deal with the MBUS DMA offsets in a central place")
Signed-off-by: Paul Kocialkowski <redacted>
---
drivers/of/device.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
@@ -181,7 +181,14 @@ int of_dma_configure_id(struct device *dev, struct device_node *np,arch_setup_dma_ops(dev,dma_start,size,iommu,coherent);-dev->dma_range_map=map;+if(!dev->dma_range_map){+dev->dma_range_map=map;+}elseif(map){+dev_warn(dev,+"DMA range map was already set, ignoring range map from dt\n");+kfree(map);+}+return0;}EXPORT_SYMBOL_GPL(of_dma_configure_id);
--
2.30.0
--
Paul Kocialkowski, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com
From: Paul Kocialkowski <hidden> Date: 2021-01-27 13:06:43
Hi,
On Fri 15 Jan 21, 18:58, Paul Kocialkowski wrote:
The DE2 display engine hardware takes physical addresses that do not
need PHYS_BASE subtracted. As a result, they should not be present
on the mbus driver match list. Remove them.
This was tested on the A83T, along with the patch allowing the DMA
range map to be non-NULL and restores a working display.
Could we get this merged ASAP (in this RC cycle), hopefully with the patch
that superseded 1/2 from this series so that we don't end up with either
CSI or DE2 broken in the next release?
Cheers,
Paul
quoted hunk
Fixes: b4bdc4fbf8d0 ("soc: sunxi: Deal with the MBUS DMA offsets in a central place")
Signed-off-by: Paul Kocialkowski <redacted>
---
drivers/soc/sunxi/sunxi_mbus.c | 5 -----
1 file changed, 5 deletions(-)
From: Maxime Ripard <hidden> Date: 2021-01-28 10:26:31
On Wed, Jan 27, 2021 at 02:03:03PM +0100, Paul Kocialkowski wrote:
Hi,
On Fri 15 Jan 21, 18:58, Paul Kocialkowski wrote:
quoted
The DE2 display engine hardware takes physical addresses that do not
need PHYS_BASE subtracted. As a result, they should not be present
on the mbus driver match list. Remove them.
This was tested on the A83T, along with the patch allowing the DMA
range map to be non-NULL and restores a working display.
Could we get this merged ASAP (in this RC cycle), hopefully with the patch
that superseded 1/2 from this series so that we don't end up with either
CSI or DE2 broken in the next release?