From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754276AbbA2PBc (ORCPT ); Thu, 29 Jan 2015 10:01:32 -0500 Received: from comal.ext.ti.com ([198.47.26.152]:40979 "EHLO comal.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754265AbbA2PAf (ORCPT ); Thu, 29 Jan 2015 10:00:35 -0500 Message-ID: <54CA4AD5.2060307@ti.com> Date: Thu, 29 Jan 2015 09:59:33 -0500 From: Murali Karicheri User-Agent: Mozilla/5.0 (X11; Linux i686; rv:12.0) Gecko/20120430 Thunderbird/12.0.1 MIME-Version: 1.0 To: Laurent Pinchart CC: Will Deacon , "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() References: <1422052359-12384-1-git-send-email-m-karicheri2@ti.com> <13812499.ICbNgSDOae@avalon> <20150128133219.GM1569@arm.com> <5349994.6VHXzPdIxs@avalon> In-Reply-To: <5349994.6VHXzPdIxs@avalon> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/28/2015 06:32 PM, Laurent Pinchart wrote: > 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. Probably the doc part can be added by Will. The iommu_np was a suggestion from Rob, if I recollect. Isn't the iommu_np points to the iommu device, and if so, iommu_np make sense. Murali > >> 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. > -- Murali Karicheri Linux Kernel, Texas Instruments From mboxrd@z Thu Jan 1 00:00:00 1970 From: Murali Karicheri Subject: Re: [PATCH v4 1/6] of: iommu: add ptr to OF node arg to of_iommu_configure() Date: Thu, 29 Jan 2015 09:59:33 -0500 Message-ID: <54CA4AD5.2060307@ti.com> References: <1422052359-12384-1-git-send-email-m-karicheri2@ti.com> <13812499.ICbNgSDOae@avalon> <20150128133219.GM1569@arm.com> <5349994.6VHXzPdIxs@avalon> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <5349994.6VHXzPdIxs@avalon> 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: Laurent Pinchart Cc: "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Russell King , Arnd Bergmann , "linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Will Deacon , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "grant.likely-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org" , "iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org" , Rob Herring , Bjorn Helgaas , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" List-Id: devicetree@vger.kernel.org On 01/28/2015 06:32 PM, Laurent Pinchart wrote: > 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. Probably the doc part can be added by Will. The iommu_np was a suggestion from Rob, if I recollect. Isn't the iommu_np points to the iommu device, and if so, iommu_np make sense. Murali > >> 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. > -- Murali Karicheri Linux Kernel, Texas Instruments From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from comal.ext.ti.com ([198.47.26.152]:40979 "EHLO comal.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754265AbbA2PAf (ORCPT ); Thu, 29 Jan 2015 10:00:35 -0500 Message-ID: <54CA4AD5.2060307@ti.com> Date: Thu, 29 Jan 2015 09:59:33 -0500 From: Murali Karicheri MIME-Version: 1.0 To: Laurent Pinchart CC: Will Deacon , "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() References: <1422052359-12384-1-git-send-email-m-karicheri2@ti.com> <13812499.ICbNgSDOae@avalon> <20150128133219.GM1569@arm.com> <5349994.6VHXzPdIxs@avalon> In-Reply-To: <5349994.6VHXzPdIxs@avalon> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Sender: linux-pci-owner@vger.kernel.org List-ID: On 01/28/2015 06:32 PM, Laurent Pinchart wrote: > 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. Probably the doc part can be added by Will. The iommu_np was a suggestion from Rob, if I recollect. Isn't the iommu_np points to the iommu device, and if so, iommu_np make sense. Murali > >> 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. > -- Murali Karicheri Linux Kernel, Texas Instruments From mboxrd@z Thu Jan 1 00:00:00 1970 From: m-karicheri2@ti.com (Murali Karicheri) Date: Thu, 29 Jan 2015 09:59:33 -0500 Subject: [PATCH v4 1/6] of: iommu: add ptr to OF node arg to of_iommu_configure() In-Reply-To: <5349994.6VHXzPdIxs@avalon> References: <1422052359-12384-1-git-send-email-m-karicheri2@ti.com> <13812499.ICbNgSDOae@avalon> <20150128133219.GM1569@arm.com> <5349994.6VHXzPdIxs@avalon> Message-ID: <54CA4AD5.2060307@ti.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 01/28/2015 06:32 PM, Laurent Pinchart wrote: > 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. Probably the doc part can be added by Will. The iommu_np was a suggestion from Rob, if I recollect. Isn't the iommu_np points to the iommu device, and if so, iommu_np make sense. Murali > >> 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. > -- Murali Karicheri Linux Kernel, Texas Instruments