From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760107AbbA2B64 (ORCPT ); Wed, 28 Jan 2015 20:58:56 -0500 Received: from galahad.ideasonboard.com ([185.26.127.97]:49595 "EHLO galahad.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754080AbbA2B6y (ORCPT ); Wed, 28 Jan 2015 20:58:54 -0500 From: Laurent Pinchart To: Will Deacon Cc: Murali Karicheri , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "linux-pci@vger.kernel.org" , "devicetree@vger.kernel.org" , "iommu@lists.linux-foundation.org" , Russell King , Arnd Bergmann , Joerg Roedel , Rob Herring , Bjorn Helgaas , "suravee.suthikulpanit@amd.com" , "grant.likely@linaro.org" Subject: Re: [PATCH v4 1/6] of: iommu: add ptr to OF node arg to of_iommu_configure() Date: Thu, 29 Jan 2015 01:32 +0200 Message-ID: <5349994.6VHXzPdIxs@avalon> User-Agent: KMail/4.14.3 (Linux/3.17.7-gentoo; KDE/4.14.3; x86_64; ; ) In-Reply-To: <20150128133219.GM1569@arm.com> References: <1422052359-12384-1-git-send-email-m-karicheri2@ti.com> <13812499.ICbNgSDOae@avalon> <20150128133219.GM1569@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Will, On Wednesday 28 January 2015 13:32:19 Will Deacon wrote: > On Wed, Jan 28, 2015 at 01:15:10PM +0000, Laurent Pinchart wrote: > > On Wednesday 28 January 2015 12:29:42 Will Deacon wrote: > >> On Wed, Jan 28, 2015 at 12:23:03PM +0000, Laurent Pinchart wrote: > >>> On Wednesday 28 January 2015 11:33:00 Will Deacon wrote: > >>>> On Mon, Jan 26, 2015 at 06:49:01PM +0000, Murali Karicheri wrote: > >>>>> On 01/25/2015 08:32 AM, Laurent Pinchart wrote: > >>>>>> On Friday 23 January 2015 17:32:34 Murali Karicheri 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. > >>>>>>> > >>>>>>> Cc: Joerg Roedel > >>>>>>> Cc: Grant Likely > >>>>>>> Cc: Rob Herring > >>>>>>> Cc: Bjorn Helgaas > >>>>>>> Cc: Will Deacon > >>>>>>> Cc: Russell King > >>>>>>> Cc: Arnd Bergmann > >>>>>>> Cc: Suravee Suthikulpanit > >>>>>>> > >>>>>>> Signed-off-by: Murali Karicheri > >>>>>>> --- > >>>>>>> > >>>>>>> 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..439235b 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 *iommu_np) > >>>>>>> { > >>>>>>> struct of_phandle_args iommu_spec; > >>>>>>> struct device_node *np; > >>>>>>> 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 > >>>>>>> */ > >>>>>> > >>>>>> Wouldn't it be better to fix this rather than passing the device > >>>>>> node pointer to the function ? The solution would be more generic. > >>>>> > >>>>> Will Deacon (Copied here) is working on this as we alteady discussed > >>>>> in this thread. So it will be addressed by him in another series. > >>>> > >>>> Well, "working on this" equates to "has it somewhere near the bottom > >>>> of a very long list" :) > >>> > >>> What's your opinion on this patch then, do you think adding the > >>> iommu_np argument makes sense as a temporary hack, or should we instead > >>> walk up the tree looking for an iommus attribute in parent nodes ? I > >>> don't expect that to be insanely difficult to code. > >> > >> If walking up the tree is useful, then I think we should do that and > >> update the Documentation to reflect the new behaviour. > > > > If I understand Murali's patch set right (please correct me if that's not > > the case) the PCI code walks up the DT nodes hierarchy to the parent node > > that contains the iommus attribute and passes a pointer to that node to > > this function. It's thus a PCI-specific solution. As a temporary hack > > that's OK I suppose, but if implementing it right straight away isn't > > difficult that would be better. > > It looks to me like the code walks the PCI topology to get the DT node for > the host controller, and passes *that* to of_dma_configure. That sounds > like the right thing to do to me, especially since the PCI topology is > likely not encoded in the device-tree. So actually, it is passing the > first parent node afaict. Indeed, that's right. I forgot for a moment that we have non-DT devices ;-) Acked-by: Laurent Pinchart Murali, nitpicking a bit, shouldn't the iommu_np parameter be renamed ? It points to the node containing the iommus parameter, not to the iommu node, so the current name is slightly confusing. A brief kerneldoc above the function would also help. This can be the subject of a separate patch. > The part I'm more interested in is the mapping of RequesterID (PCI dma > alias) to IOMMU ID when we transition from the PCI topology to the DT > topology. Currently, it seems to be 1:1 on the platforms I have, but I > doubt this will always be the case. -- Regards, Laurent Pinchart From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laurent Pinchart Subject: Re: [PATCH v4 1/6] of: iommu: add ptr to OF node arg to of_iommu_configure() Date: Thu, 29 Jan 2015 01:32 +0200 Message-ID: <5349994.6VHXzPdIxs@avalon> References: <1422052359-12384-1-git-send-email-m-karicheri2@ti.com> <13812499.ICbNgSDOae@avalon> <20150128133219.GM1569@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20150128133219.GM1569-5wv7dgnIgG8@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Will Deacon Cc: "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Russell King , Arnd Bergmann , "linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Rob Herring , "grant.likely-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org" , "iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org" , Murali Karicheri , Bjorn Helgaas , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" List-Id: devicetree@vger.kernel.org Hi Will, On Wednesday 28 January 2015 13:32:19 Will Deacon wrote: > On Wed, Jan 28, 2015 at 01:15:10PM +0000, Laurent Pinchart wrote: > > On Wednesday 28 January 2015 12:29:42 Will Deacon wrote: > >> On Wed, Jan 28, 2015 at 12:23:03PM +0000, Laurent Pinchart wrote: > >>> On Wednesday 28 January 2015 11:33:00 Will Deacon wrote: > >>>> On Mon, Jan 26, 2015 at 06:49:01PM +0000, Murali Karicheri wrote: > >>>>> On 01/25/2015 08:32 AM, Laurent Pinchart wrote: > >>>>>> On Friday 23 January 2015 17:32:34 Murali Karicheri 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. > >>>>>>> > >>>>>>> Cc: Joerg Roedel > >>>>>>> Cc: Grant Likely > >>>>>>> Cc: Rob Herring > >>>>>>> Cc: Bjorn Helgaas > >>>>>>> Cc: Will Deacon > >>>>>>> Cc: Russell King > >>>>>>> Cc: Arnd Bergmann > >>>>>>> Cc: Suravee Suthikulpanit > >>>>>>> > >>>>>>> Signed-off-by: Murali Karicheri > >>>>>>> --- > >>>>>>> > >>>>>>> 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..439235b 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 *iommu_np) > >>>>>>> { > >>>>>>> struct of_phandle_args iommu_spec; > >>>>>>> struct device_node *np; > >>>>>>> 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 > >>>>>>> */ > >>>>>> > >>>>>> Wouldn't it be better to fix this rather than passing the device > >>>>>> node pointer to the function ? The solution would be more generic. > >>>>> > >>>>> Will Deacon (Copied here) is working on this as we alteady discussed > >>>>> in this thread. So it will be addressed by him in another series. > >>>> > >>>> Well, "working on this" equates to "has it somewhere near the bottom > >>>> of a very long list" :) > >>> > >>> What's your opinion on this patch then, do you think adding the > >>> iommu_np argument makes sense as a temporary hack, or should we instead > >>> walk up the tree looking for an iommus attribute in parent nodes ? I > >>> don't expect that to be insanely difficult to code. > >> > >> If walking up the tree is useful, then I think we should do that and > >> update the Documentation to reflect the new behaviour. > > > > If I understand Murali's patch set right (please correct me if that's not > > the case) the PCI code walks up the DT nodes hierarchy to the parent node > > that contains the iommus attribute and passes a pointer to that node to > > this function. It's thus a PCI-specific solution. As a temporary hack > > that's OK I suppose, but if implementing it right straight away isn't > > difficult that would be better. > > It looks to me like the code walks the PCI topology to get the DT node for > the host controller, and passes *that* to of_dma_configure. That sounds > like the right thing to do to me, especially since the PCI topology is > likely not encoded in the device-tree. So actually, it is passing the > first parent node afaict. Indeed, that's right. I forgot for a moment that we have non-DT devices ;-) Acked-by: Laurent Pinchart Murali, nitpicking a bit, shouldn't the iommu_np parameter be renamed ? It points to the node containing the iommus parameter, not to the iommu node, so the current name is slightly confusing. A brief kerneldoc above the function would also help. This can be the subject of a separate patch. > The part I'm more interested in is the mapping of RequesterID (PCI dma > alias) to IOMMU ID when we transition from the PCI topology to the DT > topology. Currently, it seems to be 1:1 on the platforms I have, but I > doubt this will always be the case. -- Regards, Laurent Pinchart From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Laurent Pinchart To: Will Deacon Cc: Murali Karicheri , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "linux-pci@vger.kernel.org" , "devicetree@vger.kernel.org" , "iommu@lists.linux-foundation.org" , Russell King , Arnd Bergmann , Joerg Roedel , Rob Herring , Bjorn Helgaas , "suravee.suthikulpanit@amd.com" , "grant.likely@linaro.org" Subject: Re: [PATCH v4 1/6] of: iommu: add ptr to OF node arg to of_iommu_configure() Date: Thu, 29 Jan 2015 01:32 +0200 Message-ID: <5349994.6VHXzPdIxs@avalon> In-Reply-To: <20150128133219.GM1569@arm.com> References: <1422052359-12384-1-git-send-email-m-karicheri2@ti.com> <13812499.ICbNgSDOae@avalon> <20150128133219.GM1569@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org List-ID: Hi Will, On Wednesday 28 January 2015 13:32:19 Will Deacon wrote: > On Wed, Jan 28, 2015 at 01:15:10PM +0000, Laurent Pinchart wrote: > > On Wednesday 28 January 2015 12:29:42 Will Deacon wrote: > >> On Wed, Jan 28, 2015 at 12:23:03PM +0000, Laurent Pinchart wrote: > >>> On Wednesday 28 January 2015 11:33:00 Will Deacon wrote: > >>>> On Mon, Jan 26, 2015 at 06:49:01PM +0000, Murali Karicheri wrote: > >>>>> On 01/25/2015 08:32 AM, Laurent Pinchart wrote: > >>>>>> On Friday 23 January 2015 17:32:34 Murali Karicheri 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. > >>>>>>> > >>>>>>> Cc: Joerg Roedel > >>>>>>> Cc: Grant Likely > >>>>>>> Cc: Rob Herring > >>>>>>> Cc: Bjorn Helgaas > >>>>>>> Cc: Will Deacon > >>>>>>> Cc: Russell King > >>>>>>> Cc: Arnd Bergmann > >>>>>>> Cc: Suravee Suthikulpanit > >>>>>>> > >>>>>>> Signed-off-by: Murali Karicheri > >>>>>>> --- > >>>>>>> > >>>>>>> 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..439235b 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 *iommu_np) > >>>>>>> { > >>>>>>> struct of_phandle_args iommu_spec; > >>>>>>> struct device_node *np; > >>>>>>> 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 > >>>>>>> */ > >>>>>> > >>>>>> Wouldn't it be better to fix this rather than passing the device > >>>>>> node pointer to the function ? The solution would be more generic. > >>>>> > >>>>> Will Deacon (Copied here) is working on this as we alteady discussed > >>>>> in this thread. So it will be addressed by him in another series. > >>>> > >>>> Well, "working on this" equates to "has it somewhere near the bottom > >>>> of a very long list" :) > >>> > >>> What's your opinion on this patch then, do you think adding the > >>> iommu_np argument makes sense as a temporary hack, or should we instead > >>> walk up the tree looking for an iommus attribute in parent nodes ? I > >>> don't expect that to be insanely difficult to code. > >> > >> If walking up the tree is useful, then I think we should do that and > >> update the Documentation to reflect the new behaviour. > > > > If I understand Murali's patch set right (please correct me if that's not > > the case) the PCI code walks up the DT nodes hierarchy to the parent node > > that contains the iommus attribute and passes a pointer to that node to > > this function. It's thus a PCI-specific solution. As a temporary hack > > that's OK I suppose, but if implementing it right straight away isn't > > difficult that would be better. > > It looks to me like the code walks the PCI topology to get the DT node for > the host controller, and passes *that* to of_dma_configure. That sounds > like the right thing to do to me, especially since the PCI topology is > likely not encoded in the device-tree. So actually, it is passing the > first parent node afaict. Indeed, that's right. I forgot for a moment that we have non-DT devices ;-) Acked-by: Laurent Pinchart Murali, nitpicking a bit, shouldn't the iommu_np parameter be renamed ? It points to the node containing the iommus parameter, not to the iommu node, so the current name is slightly confusing. A brief kerneldoc above the function would also help. This can be the subject of a separate patch. > The part I'm more interested in is the mapping of RequesterID (PCI dma > alias) to IOMMU ID when we transition from the PCI topology to the DT > topology. Currently, it seems to be 1:1 on the platforms I have, but I > doubt this will always be the case. -- Regards, Laurent Pinchart From mboxrd@z Thu Jan 1 00:00:00 1970 From: laurent.pinchart@ideasonboard.com (Laurent Pinchart) Date: Thu, 29 Jan 2015 01:32 +0200 Subject: [PATCH v4 1/6] of: iommu: add ptr to OF node arg to of_iommu_configure() In-Reply-To: <20150128133219.GM1569@arm.com> References: <1422052359-12384-1-git-send-email-m-karicheri2@ti.com> <13812499.ICbNgSDOae@avalon> <20150128133219.GM1569@arm.com> Message-ID: <5349994.6VHXzPdIxs@avalon> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Will, On Wednesday 28 January 2015 13:32:19 Will Deacon wrote: > On Wed, Jan 28, 2015 at 01:15:10PM +0000, Laurent Pinchart wrote: > > On Wednesday 28 January 2015 12:29:42 Will Deacon wrote: > >> On Wed, Jan 28, 2015 at 12:23:03PM +0000, Laurent Pinchart wrote: > >>> On Wednesday 28 January 2015 11:33:00 Will Deacon wrote: > >>>> On Mon, Jan 26, 2015 at 06:49:01PM +0000, Murali Karicheri wrote: > >>>>> On 01/25/2015 08:32 AM, Laurent Pinchart wrote: > >>>>>> On Friday 23 January 2015 17:32:34 Murali Karicheri 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. > >>>>>>> > >>>>>>> Cc: Joerg Roedel > >>>>>>> Cc: Grant Likely > >>>>>>> Cc: Rob Herring > >>>>>>> Cc: Bjorn Helgaas > >>>>>>> Cc: Will Deacon > >>>>>>> Cc: Russell King > >>>>>>> Cc: Arnd Bergmann > >>>>>>> Cc: Suravee Suthikulpanit > >>>>>>> > >>>>>>> Signed-off-by: Murali Karicheri > >>>>>>> --- > >>>>>>> > >>>>>>> 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..439235b 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 *iommu_np) > >>>>>>> { > >>>>>>> struct of_phandle_args iommu_spec; > >>>>>>> struct device_node *np; > >>>>>>> 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 > >>>>>>> */ > >>>>>> > >>>>>> Wouldn't it be better to fix this rather than passing the device > >>>>>> node pointer to the function ? The solution would be more generic. > >>>>> > >>>>> Will Deacon (Copied here) is working on this as we alteady discussed > >>>>> in this thread. So it will be addressed by him in another series. > >>>> > >>>> Well, "working on this" equates to "has it somewhere near the bottom > >>>> of a very long list" :) > >>> > >>> What's your opinion on this patch then, do you think adding the > >>> iommu_np argument makes sense as a temporary hack, or should we instead > >>> walk up the tree looking for an iommus attribute in parent nodes ? I > >>> don't expect that to be insanely difficult to code. > >> > >> If walking up the tree is useful, then I think we should do that and > >> update the Documentation to reflect the new behaviour. > > > > If I understand Murali's patch set right (please correct me if that's not > > the case) the PCI code walks up the DT nodes hierarchy to the parent node > > that contains the iommus attribute and passes a pointer to that node to > > this function. It's thus a PCI-specific solution. As a temporary hack > > that's OK I suppose, but if implementing it right straight away isn't > > difficult that would be better. > > It looks to me like the code walks the PCI topology to get the DT node for > the host controller, and passes *that* to of_dma_configure. That sounds > like the right thing to do to me, especially since the PCI topology is > likely not encoded in the device-tree. So actually, it is passing the > first parent node afaict. Indeed, that's right. I forgot for a moment that we have non-DT devices ;-) Acked-by: Laurent Pinchart Murali, nitpicking a bit, shouldn't the iommu_np parameter be renamed ? It points to the node containing the iommus parameter, not to the iommu node, so the current name is slightly confusing. A brief kerneldoc above the function would also help. This can be the subject of a separate patch. > The part I'm more interested in is the mapping of RequesterID (PCI dma > alias) to IOMMU ID when we transition from the PCI topology to the DT > topology. Currently, it seems to be 1:1 on the platforms I have, but I > doubt this will always be the case. -- Regards, Laurent Pinchart