linux-kernel - Re: [PATCH v3 1/4] of: iommu: add ptr to OF node arg to of_iommu

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Message-ID: <54AECC86.7080201@ti.com>
Date:	Thu, 8 Jan 2015 13:29:26 -0500
From:	Murali Karicheri <m-karicheri2@...com>
To:	Rob Herring <robherring2@...il.com>
CC:	Joerg Roedel <joro@...tes.org>,
	Grant Likely <grant.likely@...aro.org>,
	Rob Herring <robh+dt@...nel.org>,
	Linux IOMMU <iommu@...ts.linux-foundation.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	Will Deacon <will.deacon@....com>,
	Russell King - ARM Linux <linux@....linux.org.uk>,
	Arnd Bergmann <arnd@...db.de>
Subject: Re: [PATCH v3 1/4] of: iommu: add ptr to OF node arg to of_iommu_configure()

On 01/07/2015 06:30 PM, Rob Herring wrote:
> On Wed, Jan 7, 2015 at 12:49 PM, Murali Karicheri<m-karicheri2@...com>  wrote:
>> Function of_iommu_configure() is called from of_dma_configure() to
>> setup iommu ops using DT property. This API is currently used for
>> platform devices for which DMA configuration (including iommu ops)
>> may come from device's parent. To extend this functionality for PCI
>> devices, this API need to take a parent node ptr as an argument
>> instead of assuming device's parent. This is needed since for PCI, the
>> dma configuration may be defined in the DT node of the root bus bridge's
>> parent device. Currently only dma-range is used for PCI and iommu is not
>> supported. So return error if the device is PCI.
>>
>> Signed-off-by: Murali Karicheri<m-karicheri2@...com>
>> ---
>>   drivers/iommu/of_iommu.c |   10 ++++++++--
>>   drivers/of/platform.c    |    2 +-
>>   include/linux/of_iommu.h |    6 ++++--
>>   3 files changed, 13 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
>> index af1dc6a..396bc77 100644
>> --- a/drivers/iommu/of_iommu.c
>> +++ b/drivers/iommu/of_iommu.c
>> @@ -133,19 +133,25 @@ struct iommu_ops *of_iommu_get_ops(struct device_node *np)
>>          return ops;
>>   }
>>
>> -struct iommu_ops *of_iommu_configure(struct device *dev)
>> +struct iommu_ops *of_iommu_configure(struct device *dev,
>> +                                    struct device_node *node)
>
> You use node here, but np in the declaration. However...
>
>>   {
>>          struct of_phandle_args iommu_spec;
>>          struct device_node *np;
>
> We also have np here. I would suggest we rename this to iommu_node or
> iommu_np to be clear which one this is for.
>
Rob,

Thanks for the comment. Will pick and use iommu_np consistently everywhere.

Murali
>>          struct iommu_ops *ops = NULL;
>>          int idx = 0;
>>
>> +       if (dev_is_pci(dev)) {
>> +               dev_err(dev, "iommu is currently not supported for PCI\n");
>> +               return NULL;
>> +       }
>> +
>>          /*
>>           * We don't currently walk up the tree looking for a parent IOMMU.
>>           * See the `Notes:' section of
>>           * Documentation/devicetree/bindings/iommu/iommu.txt
>>           */
>> -       while (!of_parse_phandle_with_args(dev->of_node, "iommus",
>> +       while (!of_parse_phandle_with_args(node, "iommus",
>>                                             "#iommu-cells", idx,
>>                                             &iommu_spec)) {
>>                  np = iommu_spec.np;
>> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
>> index a54ec10..7675b79 100644
>> --- a/drivers/of/platform.c
>> +++ b/drivers/of/platform.c
>> @@ -196,7 +196,7 @@ static void of_dma_configure(struct device *dev)
>>          dev_dbg(dev, "device is%sdma coherent\n",
>>                  coherent ? " " : " not ");
>>
>> -       iommu = of_iommu_configure(dev);
>> +       iommu = of_iommu_configure(dev, dev->of_node);
>>          dev_dbg(dev, "device is%sbehind an iommu\n",
>>                  iommu ? " " : " not ");
>>
>> diff --git a/include/linux/of_iommu.h b/include/linux/of_iommu.h
>> index 16c7554..3258cbb 100644
>> --- a/include/linux/of_iommu.h
>> +++ b/include/linux/of_iommu.h
>> @@ -12,7 +12,8 @@ extern int of_get_dma_window(struct device_node *dn, const char *prefix,
>>                               size_t *size);
>>
>>   extern void of_iommu_init(void);
>> -extern struct iommu_ops *of_iommu_configure(struct device *dev);
>> +extern struct iommu_ops *of_iommu_configure(struct device *dev,
>> +                                       struct device_node *np);
>>
>>   #else
>>
>> @@ -24,7 +25,8 @@ static inline int of_get_dma_window(struct device_node *dn, const char *prefix,
>>   }
>>
>>   static inline void of_iommu_init(void) { }
>> -static inline struct iommu_ops *of_iommu_configure(struct device *dev)
>> +static inline struct iommu_ops *of_iommu_configure(struct device *dev,
>> +                                        struct device_node *np)
>>   {
>>          return NULL;
>>   }
>> --
>> 1.7.9.5
>>


-- 
Murali Karicheri
Linux Kernel, Texas Instruments
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