From: Vivek Gautam <vivek.gautam-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org> To: Will Deacon <will.deacon-5wv7dgnIgG8@public.gmane.org>, thor.thayer-VuQAYsv1563Yd54FQh9/CA@public.gmane.org, Tomasz Figa <tfiga-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org> Cc: Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>, "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" <devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, alex.williamson-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, Linux PM <linux-pm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, sboyd-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, linux-arm-msm <linux-arm-msm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, "Rafael J. Wysocki" <rjw-LthD3rsA81gm4RdzfppkhA@public.gmane.org>, open list <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, "list-Y9sIeH5OGRo@public.gmane.org:IOMMU DRIVERS <iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>, Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>, " <iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>, robh+dt <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, freedreno <freedreno-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org>, Robin Murphy <robin.murphy-5wv7dgnIgG8@public.gmane.org> Subject: Re: [RESEND PATCH v17 5/5] iommu/arm-smmu: Add support for qcom, smmu-v2 variant Date: Fri, 23 Nov 2018 15:06:29 +0530 [thread overview] Message-ID: <CAFp+6iFhBRJWGY4Hj30tWedGpEUcnkBJrOvffmbpD2m9QMZB3A@mail.gmail.com> (raw) In-Reply-To: <CAAFQd5B-bZR8dmjARb8L4oqgET2YAjXhexAO0GKAvU4JoVU=7g-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> Hi Tomasz, On Fri, Nov 23, 2018 at 2:52 PM Tomasz Figa <tfiga@chromium.org> wrote: > > Hi Vivek, Will, > > On Fri, Nov 23, 2018 at 6:13 PM Vivek Gautam > <vivek.gautam@codeaurora.org> wrote: > > > > Hi Will, > > > > On Wed, Nov 21, 2018 at 11:09 PM Will Deacon <will.deacon@arm.com> wrote: > > > > > > [+Thor] > > > > > > On Fri, Nov 16, 2018 at 04:54:30PM +0530, Vivek Gautam wrote: > > > > qcom,smmu-v2 is an arm,smmu-v2 implementation with specific > > > > clock and power requirements. > > > > On msm8996, multiple cores, viz. mdss, video, etc. use this > > > > smmu. On sdm845, this smmu is used with gpu. > > > > Add bindings for the same. > > > > > > > > Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org> > > > > Reviewed-by: Rob Herring <robh@kernel.org> > > > > Reviewed-by: Tomasz Figa <tfiga@chromium.org> > > > > Tested-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> > > > > Reviewed-by: Robin Murphy <robin.murphy@arm.com> > > > > --- > > > > drivers/iommu/arm-smmu.c | 13 +++++++++++++ > > > > 1 file changed, 13 insertions(+) > > > > > > > > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c > > > > index 2098c3141f5f..d315ca637097 100644 > > > > --- a/drivers/iommu/arm-smmu.c > > > > +++ b/drivers/iommu/arm-smmu.c > > > > @@ -120,6 +120,7 @@ enum arm_smmu_implementation { > > > > GENERIC_SMMU, > > > > ARM_MMU500, > > > > CAVIUM_SMMUV2, > > > > + QCOM_SMMUV2, > > > > }; > > > > > > > > struct arm_smmu_s2cr { > > > > @@ -2026,6 +2027,17 @@ ARM_SMMU_MATCH_DATA(arm_mmu401, ARM_SMMU_V1_64K, GENERIC_SMMU); > > > > ARM_SMMU_MATCH_DATA(arm_mmu500, ARM_SMMU_V2, ARM_MMU500); > > > > ARM_SMMU_MATCH_DATA(cavium_smmuv2, ARM_SMMU_V2, CAVIUM_SMMUV2); > > > > > > > > +static const char * const qcom_smmuv2_clks[] = { > > > > + "bus", "iface", > > > > +}; > > > > + > > > > +static const struct arm_smmu_match_data qcom_smmuv2 = { > > > > + .version = ARM_SMMU_V2, > > > > + .model = QCOM_SMMUV2, > > > > + .clks = qcom_smmuv2_clks, > > > > + .num_clks = ARRAY_SIZE(qcom_smmuv2_clks), > > > > +}; > > > > > > These seems redundant if we go down the route proposed by Thor, where we > > > just pull all of the clocks out of the device-tree. In which case, why > > > do we need this match_data at all? > > > > Which is better? Driver relying solely on the device tree to tell > > which all clocks > > are required to be enabled, > > or, the driver deciding itself based on the platform's match data, > > that it should > > have X, Y, & Z clocks that should be supplied from the device tree. > > The former would simplify the driver, but would also make it > impossible to spot mistakes in DT, which would ultimately surface out > as very hard to debug bugs (likely complete system lockups). Thanks. Yea, this is how I understand things presently. Relying on device tree puts the things out of driver's control. Hi Will, Am I unable to understand the intentions here for Thor's clock-fetch design change? > > For qcom_smmuv2, I believe we're eventually going to end up with > platform-specific quirks anyway, so specifying the clocks too wouldn't > hurt. Given that, I'd recommend sticking to the latter, i.e. what this > patch does. > > Best regards, > Tomasz Best regards Vivek > _______________________________________________ > iommu mailing list > iommu@lists.linux-foundation.org > https://lists.linuxfoundation.org/mailman/listinfo/iommu -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation _______________________________________________ Freedreno mailing list Freedreno@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/freedreno
WARNING: multiple messages have this Message-ID (diff)
From: Vivek Gautam <vivek.gautam@codeaurora.org> To: Will Deacon <will.deacon@arm.com>, thor.thayer@linux.intel.com, Tomasz Figa <tfiga@chromium.org> Cc: Mark Rutland <mark.rutland@arm.com>, "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" <devicetree@vger.kernel.org>, Linux PM <linux-pm@vger.kernel.org>, sboyd@kernel.org, linux-arm-msm <linux-arm-msm@vger.kernel.org>, "Rafael J. Wysocki" <rjw@rjwysocki.net>, open list <linux-kernel@vger.kernel.org>, "list@263.net:IOMMU DRIVERS <iommu@lists.linux-foundation.org>, Joerg Roedel <joro@8bytes.org>," <iommu@lists.linux-foundation.org>, alex.williamson@redhat.com, "robh+dt" <robh+dt@kernel.org>, freedreno <freedreno@lists.freedesktop.org>, Robin Murphy <robin.murphy@arm.com> Subject: Re: [RESEND PATCH v17 5/5] iommu/arm-smmu: Add support for qcom,smmu-v2 variant Date: Fri, 23 Nov 2018 15:06:29 +0530 [thread overview] Message-ID: <CAFp+6iFhBRJWGY4Hj30tWedGpEUcnkBJrOvffmbpD2m9QMZB3A@mail.gmail.com> (raw) In-Reply-To: <CAAFQd5B-bZR8dmjARb8L4oqgET2YAjXhexAO0GKAvU4JoVU=7g@mail.gmail.com> Hi Tomasz, On Fri, Nov 23, 2018 at 2:52 PM Tomasz Figa <tfiga@chromium.org> wrote: > > Hi Vivek, Will, > > On Fri, Nov 23, 2018 at 6:13 PM Vivek Gautam > <vivek.gautam@codeaurora.org> wrote: > > > > Hi Will, > > > > On Wed, Nov 21, 2018 at 11:09 PM Will Deacon <will.deacon@arm.com> wrote: > > > > > > [+Thor] > > > > > > On Fri, Nov 16, 2018 at 04:54:30PM +0530, Vivek Gautam wrote: > > > > qcom,smmu-v2 is an arm,smmu-v2 implementation with specific > > > > clock and power requirements. > > > > On msm8996, multiple cores, viz. mdss, video, etc. use this > > > > smmu. On sdm845, this smmu is used with gpu. > > > > Add bindings for the same. > > > > > > > > Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org> > > > > Reviewed-by: Rob Herring <robh@kernel.org> > > > > Reviewed-by: Tomasz Figa <tfiga@chromium.org> > > > > Tested-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> > > > > Reviewed-by: Robin Murphy <robin.murphy@arm.com> > > > > --- > > > > drivers/iommu/arm-smmu.c | 13 +++++++++++++ > > > > 1 file changed, 13 insertions(+) > > > > > > > > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c > > > > index 2098c3141f5f..d315ca637097 100644 > > > > --- a/drivers/iommu/arm-smmu.c > > > > +++ b/drivers/iommu/arm-smmu.c > > > > @@ -120,6 +120,7 @@ enum arm_smmu_implementation { > > > > GENERIC_SMMU, > > > > ARM_MMU500, > > > > CAVIUM_SMMUV2, > > > > + QCOM_SMMUV2, > > > > }; > > > > > > > > struct arm_smmu_s2cr { > > > > @@ -2026,6 +2027,17 @@ ARM_SMMU_MATCH_DATA(arm_mmu401, ARM_SMMU_V1_64K, GENERIC_SMMU); > > > > ARM_SMMU_MATCH_DATA(arm_mmu500, ARM_SMMU_V2, ARM_MMU500); > > > > ARM_SMMU_MATCH_DATA(cavium_smmuv2, ARM_SMMU_V2, CAVIUM_SMMUV2); > > > > > > > > +static const char * const qcom_smmuv2_clks[] = { > > > > + "bus", "iface", > > > > +}; > > > > + > > > > +static const struct arm_smmu_match_data qcom_smmuv2 = { > > > > + .version = ARM_SMMU_V2, > > > > + .model = QCOM_SMMUV2, > > > > + .clks = qcom_smmuv2_clks, > > > > + .num_clks = ARRAY_SIZE(qcom_smmuv2_clks), > > > > +}; > > > > > > These seems redundant if we go down the route proposed by Thor, where we > > > just pull all of the clocks out of the device-tree. In which case, why > > > do we need this match_data at all? > > > > Which is better? Driver relying solely on the device tree to tell > > which all clocks > > are required to be enabled, > > or, the driver deciding itself based on the platform's match data, > > that it should > > have X, Y, & Z clocks that should be supplied from the device tree. > > The former would simplify the driver, but would also make it > impossible to spot mistakes in DT, which would ultimately surface out > as very hard to debug bugs (likely complete system lockups). Thanks. Yea, this is how I understand things presently. Relying on device tree puts the things out of driver's control. Hi Will, Am I unable to understand the intentions here for Thor's clock-fetch design change? > > For qcom_smmuv2, I believe we're eventually going to end up with > platform-specific quirks anyway, so specifying the clocks too wouldn't > hurt. Given that, I'd recommend sticking to the latter, i.e. what this > patch does. > > Best regards, > Tomasz Best regards Vivek > _______________________________________________ > iommu mailing list > iommu@lists.linux-foundation.org > https://lists.linuxfoundation.org/mailman/listinfo/iommu -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation
next prev parent reply other threads:[~2018-11-23 9:36 UTC|newest] Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-11-16 11:24 [RESEND PATCH v17 0/5] iommu/arm-smmu: Add runtime pm/sleep support Vivek Gautam 2018-11-16 11:24 ` [RESEND PATCH v17 1/5] iommu/arm-smmu: Add pm_runtime/sleep ops Vivek Gautam 2018-11-16 11:24 ` [RESEND PATCH v17 2/5] iommu/arm-smmu: Invoke pm_runtime during probe, add/remove device Vivek Gautam [not found] ` <20181116112430.31248-3-vivek.gautam-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org> 2018-11-21 17:37 ` Will Deacon 2018-11-21 17:37 ` Will Deacon [not found] ` <20181121173757.GA9801-5wv7dgnIgG8@public.gmane.org> 2018-11-22 12:02 ` Vivek Gautam 2018-11-22 12:02 ` Vivek Gautam [not found] ` <CAFp+6iEH7_XEcZNsbZfn6iBF5_o-ZKBj=DpturH7N85LU289qg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> 2018-11-23 18:36 ` Will Deacon 2018-11-23 18:36 ` Will Deacon [not found] ` <20181123183555.GE21183-5wv7dgnIgG8@public.gmane.org> 2018-11-26 6:03 ` Vivek Gautam 2018-11-26 6:03 ` Vivek Gautam [not found] ` <9064c01e-cef0-9306-078a-8d303cd6614b-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org> 2018-11-26 11:26 ` Vivek Gautam 2018-11-26 11:26 ` Vivek Gautam [not found] ` <d66c5dbf-2e44-a915-14a0-1968c8ede832-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org> 2018-11-26 19:31 ` Will Deacon 2018-11-26 19:31 ` Will Deacon [not found] ` <20181116112430.31248-1-vivek.gautam-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org> 2018-11-16 11:24 ` [RESEND PATCH v17 3/5] iommu/arm-smmu: Add the device_link between masters and smmu Vivek Gautam 2018-11-16 11:24 ` Vivek Gautam 2018-11-16 11:24 ` [RESEND PATCH v17 4/5] dt-bindings: arm-smmu: Add bindings for qcom, smmu-v2 Vivek Gautam 2018-11-16 11:24 ` [RESEND PATCH v17 4/5] dt-bindings: arm-smmu: Add bindings for qcom,smmu-v2 Vivek Gautam 2018-11-16 11:24 ` [RESEND PATCH v17 5/5] iommu/arm-smmu: Add support for qcom, smmu-v2 variant Vivek Gautam 2018-11-16 11:24 ` [RESEND PATCH v17 5/5] iommu/arm-smmu: Add support for qcom,smmu-v2 variant Vivek Gautam [not found] ` <20181116112430.31248-6-vivek.gautam-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org> 2018-11-21 17:38 ` [RESEND PATCH v17 5/5] iommu/arm-smmu: Add support for qcom, smmu-v2 variant Will Deacon 2018-11-21 17:38 ` [RESEND PATCH v17 5/5] iommu/arm-smmu: Add support for qcom,smmu-v2 variant Will Deacon [not found] ` <20181121173803.GB9801-5wv7dgnIgG8@public.gmane.org> 2018-11-23 9:13 ` [RESEND PATCH v17 5/5] iommu/arm-smmu: Add support for qcom, smmu-v2 variant Vivek Gautam 2018-11-23 9:13 ` [RESEND PATCH v17 5/5] iommu/arm-smmu: Add support for qcom,smmu-v2 variant Vivek Gautam [not found] ` <CAFp+6iELH7Mw3Ue2ksEyV+Ac8hG8--Ki69xrPCA4F-AcireRow-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> 2018-11-23 9:22 ` Tomasz Figa 2018-11-23 9:22 ` Tomasz Figa [not found] ` <CAAFQd5B-bZR8dmjARb8L4oqgET2YAjXhexAO0GKAvU4JoVU=7g-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> 2018-11-23 9:36 ` Vivek Gautam [this message] 2018-11-23 9:36 ` Vivek Gautam [not found] ` <CAFp+6iFhBRJWGY4Hj30tWedGpEUcnkBJrOvffmbpD2m9QMZB3A-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> 2018-11-23 18:34 ` Will Deacon 2018-11-23 18:34 ` Will Deacon [not found] ` <20181123183428.GD21183-5wv7dgnIgG8@public.gmane.org> 2018-11-26 4:02 ` Tomasz Figa 2018-11-26 4:02 ` Tomasz Figa 2018-11-26 10:55 ` [RESEND PATCH v17 5/5] iommu/arm-smmu: Add support for qcom, smmu-v2 variant Vivek Gautam 2018-11-26 10:55 ` [RESEND PATCH v17 5/5] iommu/arm-smmu: Add support for qcom,smmu-v2 variant Vivek Gautam 2018-11-26 14:41 ` Thor Thayer 2018-11-26 14:41 ` Thor Thayer [not found] ` <ca287382-1d21-ad73-1648-00291a5da21b-VuQAYsv1563Yd54FQh9/CA@public.gmane.org> 2018-11-26 17:55 ` [RESEND PATCH v17 5/5] iommu/arm-smmu: Add support for qcom, smmu-v2 variant Vivek Gautam 2018-11-26 17:55 ` [RESEND PATCH v17 5/5] iommu/arm-smmu: Add support for qcom,smmu-v2 variant Vivek Gautam
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