[PATCH v5 1/5] iommu: of: Fix check for returning EPROBE_DEFER

[PATCH v5 1/5] iommu: of: Fix check for returning EPROBE_DEFER

[Sricharan R]

Now with IOMMU probe deferral, we return -EPROBE_DEFER
for masters that are connected to an IOMMU which is not
probed yet, but going to get probed, so that we can attach
the correct dma_ops. So while trying to defer the probe of
the master, check if the of_iommu node that it is connected
to is marked in DT as 'status=disabled', then the IOMMU is never
is going to get probed. So simply return NULL and let the master
work without an IOMMU.

Fixes: 7b07cbefb68d ("iommu: of: Handle IOMMU lookup failure with deferred probing or error")
Signed-off-by: Sricharan R <sricharan@codeaurora.org>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Will Deacon <will.deacon@arm.com>
Tested-by: Magnus Damn <magnus.damn@gmail.com>
Acked-by: Will Deacon <will.deacon@arm.com>
---
 drivers/iommu/of_iommu.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
index 9f44ee8..e6e9bec 100644
--- a/drivers/iommu/of_iommu.c
+++ b/drivers/iommu/of_iommu.c
@@ -118,6 +118,7 @@ static bool of_iommu_driver_present(struct device_node *np)
 
 	ops = iommu_ops_from_fwnode(fwnode);
 	if ((ops && !ops->of_xlate) ||
+	    !of_device_is_available(iommu_spec->np) ||
 	    (!ops && !of_iommu_driver_present(iommu_spec->np)))
 		return NULL;
 
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation

[PATCH v5 2/5] iommu: of: Ignore all errors except EPROBE_DEFER

[Sricharan R]

While deferring the probe of IOMMU masters, xlate and
add_device callbacks called from of_iommu_configure
can pass back error values like -ENODEV, which means
the IOMMU cannot be connected with that master for real
reasons. Before the IOMMU probe deferral, all such errors
were ignored. Now all those errors are propagated back,
killing the master's probe for such errors. Instead ignore
all the errors except EPROBE_DEFER, which is the only one
of concern and let the master work without IOMMU, thus
restoring the old behavior. Also make explicit that
of_dma_configure handles only -EPROBE_DEFER from
of_iommu_configure.

Fixes: 7b07cbefb68d ("iommu: of: Handle IOMMU lookup failure with deferred probing or error")
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Magnus Damn <magnus.damn@gmail.com>
Signed-off-by: Sricharan R <sricharan@codeaurora.org>
---
[v5] Added the check in of_dma_configure

 drivers/iommu/of_iommu.c | 6 ++++++
 drivers/of/device.c      | 4 ++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
index e6e9bec..19779b8 100644
--- a/drivers/iommu/of_iommu.c
+++ b/drivers/iommu/of_iommu.c
@@ -237,6 +237,12 @@ const struct iommu_ops *of_iommu_configure(struct device *dev,
 			ops = ERR_PTR(err);
 	}
 
+	/* Ignore all other errors apart from EPROBE_DEFER */
+	if (IS_ERR(ops) && (PTR_ERR(ops) != -EPROBE_DEFER)) {
+		dev_dbg(dev, "Adding to IOMMU failed: %ld\n", PTR_ERR(ops));
+		ops = NULL;
+	}
+
 	return ops;
 }
 
diff --git a/drivers/of/device.c b/drivers/of/device.c
index 9416d05..28c38c7 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -144,8 +144,8 @@ int of_dma_configure(struct device *dev, struct device_node *np)
 		coherent ? " " : " not ");
 
 	iommu = of_iommu_configure(dev, np);
-	if (IS_ERR(iommu))
-		return PTR_ERR(iommu);
+	if (IS_ERR(iommu) && PTR_ERR(iommu) == -EPROBE_DEFER)
+		return -EPROBE_DEFER;
 
 	dev_dbg(dev, "device is%sbehind an iommu\n",
 		iommu ? " " : " not ");
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation

[PATCH v5 3/5] ACPI/IORT: Ignore all errors except EPROBE_DEFER

[Sricharan R]

While deferring the probe of IOMMU masters, xlate and
add_device callbacks called from iort_iommu_configure
can pass back error values like -ENODEV, which means
the IOMMU cannot be connected with that master for real
reasons. Before the IOMMU probe deferral, all such errors
were ignored. Now all those errors are propagated back,
killing the master's probe for such errors. Instead ignore
all the errors except EPROBE_DEFER, which is the only one
of concern and let the master work without IOMMU, thus
restoring the old behavior. Also make explicit that
acpi_dma_configure handles only -EPROBE_DEFER from
iort_iommu_configure.

Fixes: 5a1bb638d567 ("drivers: acpi: Handle IOMMU lookup failure with deferred probing or error")
Signed-off-by: Sricharan R <sricharan@codeaurora.org>
---
[v5] Added the check in acpi_dma_configure

 drivers/acpi/arm64/iort.c | 6 ++++++
 drivers/acpi/scan.c       | 4 ++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index c5fecf9..16e101f 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -782,6 +782,12 @@ const struct iommu_ops *iort_iommu_configure(struct device *dev)
 	if (err)
 		ops = ERR_PTR(err);
 
+	/* Ignore all other errors apart from EPROBE_DEFER */
+	if (IS_ERR(ops) && (PTR_ERR(ops) != -EPROBE_DEFER)) {
+		dev_dbg(dev, "Adding to IOMMU failed: %ld\n", PTR_ERR(ops));
+		ops = NULL;
+	}
+
 	return ops;
 }
 
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index e39ec7b..3a10d757 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -1371,8 +1371,8 @@ int acpi_dma_configure(struct device *dev, enum dev_dma_attr attr)
 	iort_set_dma_mask(dev);
 
 	iommu = iort_iommu_configure(dev);
-	if (IS_ERR(iommu))
-		return PTR_ERR(iommu);
+	if (IS_ERR(iommu) && PTR_ERR(iommu) == -EPROBE_DEFER)
+		return -EPROBE_DEFER;
 
 	size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1);
 	/*
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation

[PATCH v5 4/5] ARM: dma-mapping: Don't tear third-party mappings

[Sricharan R]

From: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

arch_setup_dma_ops() is used in device probe code paths to create an
IOMMU mapping and attach it to the device. The function assumes that the
device is attached to a device-specific IOMMU instance (or at least a
device-specific TLB in a shared IOMMU instance) and thus creates a
separate mapping for every device.

On several systems (Renesas R-Car Gen2 being one of them), that
assumption is not true, and IOMMU mappings must be shared between
multiple devices. In those cases the IOMMU driver knows better than the
generic ARM dma-mapping layer and attaches mapping to devices manually
with arm_iommu_attach_device(), which sets the DMA ops for the device.

The arch_setup_dma_ops() function takes this into account and bails out
immediately if the device already has DMA ops assigned. However, the
corresponding arch_teardown_dma_ops() function, called from driver
unbind code paths (including probe deferral), will tear the mapping down
regardless of who created it. When the device is reprobed
arch_setup_dma_ops() will be called again but won't perform any
operation as the DMA ops will still be set.

We need to reset the DMA ops in arch_teardown_dma_ops() to fix this.
However, we can't do so unconditionally, as then a new mapping would be
created by arch_setup_dma_ops() when the device is reprobed, regardless
of whether the device needs to share a mapping or not. We must thus keep
track of whether arch_setup_dma_ops() created the mapping, and only in
that case tear it down in arch_teardown_dma_ops().

Keep track of that information in the dev_archdata structure. As the
structure is embedded in all instances of struct device let's not grow
it, but turn the existing dma_coherent bool field into a bitfield that
can be used for other purposes.

Fixes: 09515ef5ddad ("of/acpi: Configure dma operations at probe time for platform/amba/pci bus devices")
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
---
 arch/arm/include/asm/device.h | 3 ++-
 arch/arm/mm/dma-mapping.c     | 4 ++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/arm/include/asm/device.h b/arch/arm/include/asm/device.h
index 36ec9c8..3234fe9 100644
--- a/arch/arm/include/asm/device.h
+++ b/arch/arm/include/asm/device.h
@@ -19,7 +19,8 @@ struct dev_archdata {
 #ifdef CONFIG_XEN
 	const struct dma_map_ops *dev_dma_ops;
 #endif
-	bool dma_coherent;
+	unsigned int dma_coherent:1;
+	unsigned int dma_ops_setup:1;
 };
 
 struct omap_device;
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index c742dfd..b48998f 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -2430,9 +2430,13 @@ void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
 		dev->dma_ops = xen_dma_ops;
 	}
 #endif
+	dev->archdata.dma_ops_setup = true;
 }
 
 void arch_teardown_dma_ops(struct device *dev)
 {
+	if (!dev->archdata.dma_ops_setup)
+		return;
+
 	arm_teardown_iommu_dma_ops(dev);
 }
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation

[PATCH v5 5/5] ACPI/IORT: Move the check to get iommu_ops from translated fwspec

[Sricharan R]

From: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

With IOMMU probe deferral, iort_iommu_configure can be called
multiple times for the same device. Hence we have a check
to see if the device's fwspec is already translated and return
the iommu_ops from that directly. But the check is wrongly
placed in iort_iommu_xlate, which breaks devices with multiple
sids. Move the check to iort_iommu_configure.

Fixes: 5a1bb638d567 ("drivers: acpi: Handle IOMMU lookup failure with deferred probing or error")
Tested-by: Nate Watterson <nwatters@codeaurora.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
---

[v5] new patch

 drivers/acpi/arm64/iort.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index 16e101f..797b28d 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -666,14 +666,6 @@ static const struct iommu_ops *iort_iommu_xlate(struct device *dev,
 	int ret = -ENODEV;
 	struct fwnode_handle *iort_fwnode;
 
-	/*
-	 * If we already translated the fwspec there
-	 * is nothing left to do, return the iommu_ops.
-	 */
-	ops = iort_fwspec_iommu_ops(dev->iommu_fwspec);
-	if (ops)
-		return ops;
-
 	if (node) {
 		iort_fwnode = iort_get_fwnode(node);
 		if (!iort_fwnode)
@@ -735,6 +727,14 @@ const struct iommu_ops *iort_iommu_configure(struct device *dev)
 	u32 streamid = 0;
 	int err;
 
+	/*
+	 * If we already translated the fwspec there
+	 * is nothing left to do, return the iommu_ops.
+	 */
+	ops = iort_fwspec_iommu_ops(dev->iommu_fwspec);
+	if (ops)
+		return ops;
+
 	if (dev_is_pci(dev)) {
 		struct pci_bus *bus = to_pci_dev(dev)->bus;
 		u32 rid;
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation

Re: [PATCH v5 1/5] iommu: of: Fix check for returning EPROBE_DEFER

[Joerg Roedel]

On Tue, May 23, 2017 at 06:31:29PM +0530, Sricharan R wrote:
> Now with IOMMU probe deferral, we return -EPROBE_DEFER
> for masters that are connected to an IOMMU which is not
> probed yet, but going to get probed, so that we can attach
> the correct dma_ops. So while trying to defer the probe of
> the master, check if the of_iommu node that it is connected
> to is marked in DT as 'status=disabled', then the IOMMU is never
> is going to get probed. So simply return NULL and let the master
> work without an IOMMU.
> 
> Fixes: 7b07cbefb68d ("iommu: of: Handle IOMMU lookup failure with deferred probing or error")
> Signed-off-by: Sricharan R <sricharan@codeaurora.org>
> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Tested-by: Will Deacon <will.deacon@arm.com>
> Tested-by: Magnus Damn <magnus.damn@gmail.com>
> Acked-by: Will Deacon <will.deacon@arm.com>

Applied all to iommu/fixes, thanks.