diff mbox

[V7,07/11] iommu: of: Handle IOMMU lookup failure with deferred probing or error

Message ID 1485188293-20263-8-git-send-email-sricharan@codeaurora.org
State Not Applicable
Headers show

Commit Message

Sricharan Ramabadhran Jan. 23, 2017, 4:18 p.m. UTC 
From: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

Failures to look up an IOMMU when parsing the DT iommus property need to
be handled separately from the .of_xlate() failures to support deferred
probing.

The lack of a registered IOMMU can be caused by the lack of a driver for
the IOMMU, the IOMMU device probe not having been performed yet, having
been deferred, or having failed.

The first case occurs when the device tree describes the bus master and
IOMMU topology correctly but no device driver exists for the IOMMU yet
or the device driver has not been compiled in. Return NULL, the caller
will configure the device without an IOMMU.

The second and third cases are handled by deferring the probe of the bus
master device which will eventually get reprobed after the IOMMU.

The last case is currently handled by deferring the probe of the bus
master device as well. A mechanism to either configure the bus master
device without an IOMMU or to fail the bus master device probe depending
on whether the IOMMU is optional or mandatory would be a good
enhancement.

Signed-off-by: Laurent Pichart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Sricharan R <sricharan@codeaurora.org>
---
 drivers/base/dma-mapping.c | 5 +++--
 drivers/iommu/of_iommu.c   | 5 +++--
 drivers/of/device.c        | 9 +++++++--
 include/linux/of_device.h  | 9 ++++++---
 4 files changed, 19 insertions(+), 9 deletions(-)

Comments

Bjorn Helgaas Jan. 28, 2017, 9:03 p.m. UTC | #1 
On Mon, Jan 23, 2017 at 09:48:09PM +0530, Sricharan R wrote:
> From: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> 
> Failures to look up an IOMMU when parsing the DT iommus property need to
> be handled separately from the .of_xlate() failures to support deferred
> probing.
> 
> The lack of a registered IOMMU can be caused by the lack of a driver for
> the IOMMU, the IOMMU device probe not having been performed yet, having
> been deferred, or having failed.
> 
> The first case occurs when the device tree describes the bus master and
> IOMMU topology correctly but no device driver exists for the IOMMU yet
> or the device driver has not been compiled in. Return NULL, the caller
> will configure the device without an IOMMU.
> 
> The second and third cases are handled by deferring the probe of the bus
> master device which will eventually get reprobed after the IOMMU.
> 
> The last case is currently handled by deferring the probe of the bus
> master device as well. A mechanism to either configure the bus master
> device without an IOMMU or to fail the bus master device probe depending
> on whether the IOMMU is optional or mandatory would be a good
> enhancement.
> 
> Signed-off-by: Laurent Pichart <laurent.pinchart+renesas@ideasonboard.com>
> Signed-off-by: Sricharan R <sricharan@codeaurora.org>
> ...

> diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
> index 349bd1d..9529d6c 100644
> --- a/drivers/iommu/of_iommu.c
> +++ b/drivers/iommu/of_iommu.c
> @@ -23,6 +23,7 @@
>  #include <linux/of.h>
>  #include <linux/of_iommu.h>
>  #include <linux/of_pci.h>
> +#include <linux/pci.h>

Why do we need this?

>  #include <linux/slab.h>
>  
>  static const struct of_device_id __iommu_of_table_sentinel
> @@ -223,7 +224,7 @@ const struct iommu_ops *of_iommu_configure(struct device *dev,
>  			ops = ERR_PTR(err);
>  	}
>  
> -	return IS_ERR(ops) ? NULL : ops;
> +	return ops;
>  }
>  
>  static int __init of_iommu_init(void)
> @@ -234,7 +235,7 @@ static int __init of_iommu_init(void)
>  	for_each_matching_node_and_match(np, matches, &match) {
>  		const of_iommu_init_fn init_fn = match->data;
>  
> -		if (init_fn(np))
> +		if (init_fn && init_fn(np))
>  			pr_err("Failed to initialise IOMMU %s\n",
>  				of_node_full_name(np));
>  	}
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Sinan Kaya Jan. 29, 2017, 4:36 p.m. UTC | #2 
On 1/23/2017 11:18 AM, Sricharan R wrote:
> @@ -107,7 +107,7 @@ void of_dma_configure(struct device *dev, struct device_node *np)
>  	ret = of_dma_get_range(np, &dma_addr, &paddr, &size);
>  	if (ret < 0) {
>  		dma_addr = offset = 0;
> -		size = dev->coherent_dma_mask + 1;
> +		size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1);
>  	} else {

what's happening here?
Sricharan Ramabadhran Jan. 30, 2017, 8:01 a.m. UTC | #3 
Hi Bjorn,

>-----Original Message-----
>From: Bjorn Helgaas [mailto:helgaas@kernel.org]
>Sent: Sunday, January 29, 2017 2:34 AM
>To: Sricharan R <sricharan@codeaurora.org>
>Cc: robin.murphy@arm.com; will.deacon@arm.com; joro@8bytes.org; lorenzo.pieralisi@arm.com; iommu@lists.linux-foundation.org;
>linux-arm-kernel@lists.infradead.org; linux-arm-msm@vger.kernel.org; m.szyprowski@samsung.com; bhelgaas@google.com; linux-
>pci@vger.kernel.org; linux-acpi@vger.kernel.org
>Subject: Re: [PATCH V7 07/11] iommu: of: Handle IOMMU lookup failure with deferred probing or error
>
>On Mon, Jan 23, 2017 at 09:48:09PM +0530, Sricharan R wrote:
>> From: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
>>
>> Failures to look up an IOMMU when parsing the DT iommus property need to
>> be handled separately from the .of_xlate() failures to support deferred
>> probing.
>>
>> The lack of a registered IOMMU can be caused by the lack of a driver for
>> the IOMMU, the IOMMU device probe not having been performed yet, having
>> been deferred, or having failed.
>>
>> The first case occurs when the device tree describes the bus master and
>> IOMMU topology correctly but no device driver exists for the IOMMU yet
>> or the device driver has not been compiled in. Return NULL, the caller
>> will configure the device without an IOMMU.
>>
>> The second and third cases are handled by deferring the probe of the bus
>> master device which will eventually get reprobed after the IOMMU.
>>
>> The last case is currently handled by deferring the probe of the bus
>> master device as well. A mechanism to either configure the bus master
>> device without an IOMMU or to fail the bus master device probe depending
>> on whether the IOMMU is optional or mandatory would be a good
>> enhancement.
>>
>> Signed-off-by: Laurent Pichart <laurent.pinchart+renesas@ideasonboard.com>
>> Signed-off-by: Sricharan R <sricharan@codeaurora.org>
>> ...
>
>> diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
>> index 349bd1d..9529d6c 100644
>> --- a/drivers/iommu/of_iommu.c
>> +++ b/drivers/iommu/of_iommu.c
>> @@ -23,6 +23,7 @@
>>  #include <linux/of.h>
>>  #include <linux/of_iommu.h>
>>  #include <linux/of_pci.h>
>> +#include <linux/pci.h>
>
>Why do we need this?

Right, will remove it.

Regards,
 Sricharan

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Sricharan Ramabadhran Jan. 30, 2017, noon UTC | #4 
Hi,

>-----Original Message-----
>From: linux-arm-kernel [mailto:linux-arm-kernel-bounces@lists.infradead.org] On Behalf Of Sinan Kaya
>Sent: Sunday, January 29, 2017 10:06 PM
>To: Sricharan R <sricharan@codeaurora.org>; robin.murphy@arm.com; will.deacon@arm.com; joro@8bytes.org;
>lorenzo.pieralisi@arm.com; iommu@lists.linux-foundation.org; linux-arm-kernel@lists.infradead.org; linux-arm-
>msm@vger.kernel.org; m.szyprowski@samsung.com; bhelgaas@google.com; linux-pci@vger.kernel.org; linux-acpi@vger.kernel.org
>Subject: Re: [PATCH V7 07/11] iommu: of: Handle IOMMU lookup failure with deferred probing or error
>
>On 1/23/2017 11:18 AM, Sricharan R wrote:
>> @@ -107,7 +107,7 @@ void of_dma_configure(struct device *dev, struct device_node *np)
>>  	ret = of_dma_get_range(np, &dma_addr, &paddr, &size);
>>  	if (ret < 0) {
>>  		dma_addr = offset = 0;
>> -		size = dev->coherent_dma_mask + 1;
>> +		size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1);
>>  	} else {
>
>what's happening here?

Sorry, not relevant. Will remove this. Has come in because of some rebase mistake.

Regards,
 Sricharan

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diff mbox

Patch

diff --git a/drivers/base/dma-mapping.c b/drivers/base/dma-mapping.c
index 449b948..82bd45c 100644
--- a/drivers/base/dma-mapping.c
+++ b/drivers/base/dma-mapping.c
@@ -353,6 +353,7 @@  int dma_configure(struct device *dev)
 {
 	struct device *bridge = NULL, *dma_dev = dev;
 	enum dev_dma_attr attr;
+	int ret = 0;
 
 	if (dev_is_pci(dev)) {
 		bridge = pci_get_host_bridge_device(to_pci_dev(dev));
@@ -363,7 +364,7 @@  int dma_configure(struct device *dev)
 	}
 
 	if (dma_dev->of_node) {
-		of_dma_configure(dev, dma_dev->of_node);
+		ret = of_dma_configure(dev, dma_dev->of_node);
 	} else if (has_acpi_companion(dma_dev)) {
 		attr = acpi_get_dma_attr(to_acpi_device_node(dma_dev->fwnode));
 		if (attr != DEV_DMA_NOT_SUPPORTED)
@@ -373,7 +374,7 @@  int dma_configure(struct device *dev)
 	if (bridge)
 		pci_put_host_bridge_device(bridge);
 
-	return 0;
+	return ret;
 }
 
 void dma_deconfigure(struct device *dev)
diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
index 349bd1d..9529d6c 100644
--- a/drivers/iommu/of_iommu.c
+++ b/drivers/iommu/of_iommu.c
@@ -23,6 +23,7 @@ 
 #include <linux/of.h>
 #include <linux/of_iommu.h>
 #include <linux/of_pci.h>
+#include <linux/pci.h>
 #include <linux/slab.h>
 
 static const struct of_device_id __iommu_of_table_sentinel
@@ -223,7 +224,7 @@  const struct iommu_ops *of_iommu_configure(struct device *dev,
 			ops = ERR_PTR(err);
 	}
 
-	return IS_ERR(ops) ? NULL : ops;
+	return ops;
 }
 
 static int __init of_iommu_init(void)
@@ -234,7 +235,7 @@  static int __init of_iommu_init(void)
 	for_each_matching_node_and_match(np, matches, &match) {
 		const of_iommu_init_fn init_fn = match->data;
 
-		if (init_fn(np))
+		if (init_fn && init_fn(np))
 			pr_err("Failed to initialise IOMMU %s\n",
 				of_node_full_name(np));
 	}
diff --git a/drivers/of/device.c b/drivers/of/device.c
index 1c843e2..d58595c 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -82,7 +82,7 @@  int of_device_add(struct platform_device *ofdev)
  * can use a platform bus notifier and handle BUS_NOTIFY_ADD_DEVICE events
  * to fix up DMA configuration.
  */
-void of_dma_configure(struct device *dev, struct device_node *np)
+int of_dma_configure(struct device *dev, struct device_node *np)
 {
 	u64 dma_addr, paddr, size;
 	int ret;
@@ -107,7 +107,7 @@  void of_dma_configure(struct device *dev, struct device_node *np)
 	ret = of_dma_get_range(np, &dma_addr, &paddr, &size);
 	if (ret < 0) {
 		dma_addr = offset = 0;
-		size = dev->coherent_dma_mask + 1;
+		size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1);
 	} else {
 		offset = PFN_DOWN(paddr - dma_addr);
 		dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", offset);
@@ -129,10 +129,15 @@  void 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);
+
 	dev_dbg(dev, "device is%sbehind an iommu\n",
 		iommu ? " " : " not ");
 
 	arch_setup_dma_ops(dev, dma_addr, size, iommu, coherent);
+
+	return 0;
 }
 EXPORT_SYMBOL_GPL(of_dma_configure);
 
diff --git a/include/linux/of_device.h b/include/linux/of_device.h
index d20a31a..6dca65c 100644
--- a/include/linux/of_device.h
+++ b/include/linux/of_device.h
@@ -55,7 +55,7 @@  static inline struct device_node *of_cpu_device_node_get(int cpu)
 	return of_node_get(cpu_dev->of_node);
 }
 
-void of_dma_configure(struct device *dev, struct device_node *np);
+int of_dma_configure(struct device *dev, struct device_node *np);
 void of_dma_deconfigure(struct device *dev);
 #else /* CONFIG_OF */
 
@@ -99,8 +99,11 @@  static inline struct device_node *of_cpu_device_node_get(int cpu)
 {
 	return NULL;
 }
-static inline void of_dma_configure(struct device *dev, struct device_node *np)
-{}
+
+static inline int of_dma_configure(struct device *dev, struct device_node *np)
+{
+	return 0;
+}
 static inline void of_dma_deconfigure(struct device *dev)
 {}
 #endif /* CONFIG_OF */