From: Rob Herring <robh@kernel.org> To: Suzuki K Poulose <suzuki.poulose@arm.com> Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, mathieu.poirier@linaro.org, mike.leach@linaro.org, robert.walker@arm.com, mark.rutland@arm.com, will.deacon@arm.com, robin.murphy@arm.com, sudeep.holla@arm.com, frowand.list@gmail.com, john.horley@arm.com, Mathieu Poirier <matheiu.poirier@linaro.org>, devicetree@vger.kernel.org Subject: Re: [PATCH v2 10/27] dts: bindings: Restrict coresight tmc-etr scatter-gather mode Date: Tue, 1 May 2018 08:13:00 -0500 [thread overview] Message-ID: <20180501131300.GA31425@rob-hp-laptop> (raw) In-Reply-To: <1525165857-11096-11-git-send-email-suzuki.poulose@arm.com> On Tue, May 01, 2018 at 10:10:40AM +0100, Suzuki K Poulose wrote: > We are about to add the support for ETR builtin scatter-gather mode > for dealing with large amount of trace buffers. However, on some of > the platforms, using the ETR SG mode can lock up the system due to > the way the ETR is connected to the memory subsystem. > > In SG mode, the ETR performs READ from the scatter-gather table to > fetch the next page and regular WRITE of trace data. If the READ > operation doesn't complete(due to the memory subsystem issues, > which we have seen on a couple of platforms) the trace WRITE > cannot proceed leading to issues. So, we by default do not > use the SG mode, unless it is known to be safe on the platform. > We define a DT property for the TMC node to specify whether we > have a proper SG mode. > > Cc: Mathieu Poirier <matheiu.poirier@linaro.org> > Cc: Mike Leach <mike.leach@linaro.org> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: John Horley <john.horley@arm.com> > Cc: Robert Walker <robert.walker@arm.com> > Cc: devicetree@vger.kernel.org > Cc: frowand.list@gmail.com > Cc: Rob Herring <robh@kernel.org> > Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> > --- > Documentation/devicetree/bindings/arm/coresight.txt | 3 +++ > drivers/hwtracing/coresight/coresight-tmc.c | 8 +++++++- > 2 files changed, 10 insertions(+), 1 deletion(-) > > diff --git a/Documentation/devicetree/bindings/arm/coresight.txt b/Documentation/devicetree/bindings/arm/coresight.txt > index cdd84d0..7c0c8f0 100644 > --- a/Documentation/devicetree/bindings/arm/coresight.txt > +++ b/Documentation/devicetree/bindings/arm/coresight.txt > @@ -88,6 +88,9 @@ its hardware characteristcs. > * arm,buffer-size: size of contiguous buffer space for TMC ETR > (embedded trace router) > > + * scatter-gather: boolean. Indicates that the TMC-ETR can safely > + use the SG mode on this system. > + Needs a vendor prefix. > * Optional property for CATU : > * interrupts : Exactly one SPI may be listed for reporting the address > error
WARNING: multiple messages have this Message-ID (diff)
From: robh@kernel.org (Rob Herring) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v2 10/27] dts: bindings: Restrict coresight tmc-etr scatter-gather mode Date: Tue, 1 May 2018 08:13:00 -0500 [thread overview] Message-ID: <20180501131300.GA31425@rob-hp-laptop> (raw) In-Reply-To: <1525165857-11096-11-git-send-email-suzuki.poulose@arm.com> On Tue, May 01, 2018 at 10:10:40AM +0100, Suzuki K Poulose wrote: > We are about to add the support for ETR builtin scatter-gather mode > for dealing with large amount of trace buffers. However, on some of > the platforms, using the ETR SG mode can lock up the system due to > the way the ETR is connected to the memory subsystem. > > In SG mode, the ETR performs READ from the scatter-gather table to > fetch the next page and regular WRITE of trace data. If the READ > operation doesn't complete(due to the memory subsystem issues, > which we have seen on a couple of platforms) the trace WRITE > cannot proceed leading to issues. So, we by default do not > use the SG mode, unless it is known to be safe on the platform. > We define a DT property for the TMC node to specify whether we > have a proper SG mode. > > Cc: Mathieu Poirier <matheiu.poirier@linaro.org> > Cc: Mike Leach <mike.leach@linaro.org> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: John Horley <john.horley@arm.com> > Cc: Robert Walker <robert.walker@arm.com> > Cc: devicetree at vger.kernel.org > Cc: frowand.list at gmail.com > Cc: Rob Herring <robh@kernel.org> > Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> > --- > Documentation/devicetree/bindings/arm/coresight.txt | 3 +++ > drivers/hwtracing/coresight/coresight-tmc.c | 8 +++++++- > 2 files changed, 10 insertions(+), 1 deletion(-) > > diff --git a/Documentation/devicetree/bindings/arm/coresight.txt b/Documentation/devicetree/bindings/arm/coresight.txt > index cdd84d0..7c0c8f0 100644 > --- a/Documentation/devicetree/bindings/arm/coresight.txt > +++ b/Documentation/devicetree/bindings/arm/coresight.txt > @@ -88,6 +88,9 @@ its hardware characteristcs. > * arm,buffer-size: size of contiguous buffer space for TMC ETR > (embedded trace router) > > + * scatter-gather: boolean. Indicates that the TMC-ETR can safely > + use the SG mode on this system. > + Needs a vendor prefix. > * Optional property for CATU : > * interrupts : Exactly one SPI may be listed for reporting the address > error
next prev parent reply other threads:[~2018-05-01 13:13 UTC|newest] Thread overview: 134+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-05-01 9:10 [PATCH v2 00/27] coresight: TMC ETR backend support for perf Suzuki K Poulose 2018-05-01 9:10 ` Suzuki K Poulose 2018-05-01 9:10 ` [PATCH v2 01/27] coresight: ETM: Add support for ARM Cortex-A73 Suzuki K Poulose 2018-05-01 9:10 ` Suzuki K Poulose 2018-05-01 9:10 ` [PATCH v2 02/27] coresight: Cleanup device subtype struct Suzuki K Poulose 2018-05-01 9:10 ` Suzuki K Poulose 2018-05-01 9:10 ` [PATCH v2 03/27] coresight: Add helper device type Suzuki K Poulose 2018-05-01 9:10 ` Suzuki K Poulose 2018-05-03 17:00 ` Mathieu Poirier 2018-05-03 17:00 ` Mathieu Poirier 2018-05-05 9:56 ` Suzuki K Poulose 2018-05-05 9:56 ` Suzuki K Poulose 2018-05-01 9:10 ` [PATCH v2 04/27] coresight: Introduce support for Coresight Addrss Translation Unit Suzuki K Poulose 2018-05-01 9:10 ` Suzuki K Poulose 2018-05-03 17:31 ` Mathieu Poirier 2018-05-03 17:31 ` Mathieu Poirier 2018-05-03 20:25 ` Mathieu Poirier 2018-05-03 20:25 ` Mathieu Poirier 2018-05-05 10:03 ` Suzuki K Poulose 2018-05-05 10:03 ` Suzuki K Poulose 2018-05-01 9:10 ` [PATCH v2 05/27] dts: bindings: Document device tree binding for CATU Suzuki K Poulose 2018-05-01 9:10 ` Suzuki K Poulose 2018-05-01 13:10 ` Rob Herring 2018-05-01 13:10 ` Rob Herring 2018-05-03 17:42 ` Mathieu Poirier 2018-05-03 17:42 ` Mathieu Poirier 2018-05-08 15:40 ` Suzuki K Poulose 2018-05-08 15:40 ` Suzuki K Poulose 2018-05-11 16:05 ` Rob Herring 2018-05-11 16:05 ` Rob Herring 2018-05-14 14:42 ` Mathieu Poirier 2018-05-14 14:42 ` Mathieu Poirier 2018-05-01 9:10 ` [PATCH v2 06/27] coresight: tmc etr: Disallow perf mode temporarily Suzuki K Poulose 2018-05-01 9:10 ` Suzuki K Poulose 2018-05-01 9:10 ` [PATCH v2 07/27] coresight: tmc: Hide trace buffer handling for file read Suzuki K Poulose 2018-05-01 9:10 ` Suzuki K Poulose 2018-05-03 19:50 ` Mathieu Poirier 2018-05-03 19:50 ` Mathieu Poirier 2018-05-01 9:10 ` [PATCH v2 08/27] coresight: tmc-etr: Do not clean trace buffer Suzuki K Poulose 2018-05-01 9:10 ` Suzuki K Poulose 2018-05-01 9:10 ` [PATCH v2 09/27] coresight: Add helper for inserting synchronization packets Suzuki K Poulose 2018-05-01 9:10 ` Suzuki K Poulose 2018-05-01 9:10 ` [PATCH v2 10/27] dts: bindings: Restrict coresight tmc-etr scatter-gather mode Suzuki K Poulose 2018-05-01 9:10 ` Suzuki K Poulose 2018-05-01 13:13 ` Rob Herring [this message] 2018-05-01 13:13 ` Rob Herring 2018-05-03 20:32 ` Mathieu Poirier 2018-05-03 20:32 ` Mathieu Poirier 2018-05-04 22:56 ` Rob Herring 2018-05-04 22:56 ` Rob Herring 2018-05-08 15:48 ` Suzuki K Poulose 2018-05-08 15:48 ` Suzuki K Poulose 2018-05-08 17:34 ` Rob Herring 2018-05-08 17:34 ` Rob Herring 2018-05-01 9:10 ` [PATCH v2 11/27] dts: juno: Add scatter-gather support for all revisions Suzuki K Poulose 2018-05-01 9:10 ` Suzuki K Poulose 2018-05-01 9:10 ` [PATCH v2 12/27] coresight: tmc-etr: Allow commandline option to override SG use Suzuki K Poulose 2018-05-01 9:10 ` Suzuki K Poulose 2018-05-03 20:40 ` Mathieu Poirier 2018-05-03 20:40 ` Mathieu Poirier 2018-05-08 15:49 ` Suzuki K Poulose 2018-05-08 15:49 ` Suzuki K Poulose 2018-05-01 9:10 ` [PATCH v2 13/27] coresight: Add generic TMC sg table framework Suzuki K Poulose 2018-05-01 9:10 ` Suzuki K Poulose 2018-05-04 17:35 ` Mathieu Poirier 2018-05-04 17:35 ` Mathieu Poirier 2018-05-01 9:10 ` [PATCH v2 14/27] coresight: Add support for TMC ETR SG unit Suzuki K Poulose 2018-05-01 9:10 ` Suzuki K Poulose 2018-05-01 9:10 ` [PATCH v2 15/27] coresight: tmc-etr: Make SG table circular Suzuki K Poulose 2018-05-01 9:10 ` Suzuki K Poulose 2018-05-01 9:10 ` [PATCH v2 16/27] coresight: tmc-etr: Add transparent buffer management Suzuki K Poulose 2018-05-01 9:10 ` Suzuki K Poulose 2018-05-07 17:20 ` Mathieu Poirier 2018-05-07 17:20 ` Mathieu Poirier 2018-05-01 9:10 ` [PATCH v2 17/27] coresight: etr: Add support for save restore buffers Suzuki K Poulose 2018-05-01 9:10 ` Suzuki K Poulose 2018-05-07 17:48 ` Mathieu Poirier 2018-05-07 17:48 ` Mathieu Poirier 2018-05-01 9:10 ` [PATCH v2 18/27] coresight: catu: Add support for scatter gather tables Suzuki K Poulose 2018-05-01 9:10 ` Suzuki K Poulose 2018-05-07 20:25 ` Mathieu Poirier 2018-05-07 20:25 ` Mathieu Poirier 2018-05-08 15:56 ` Suzuki K Poulose 2018-05-08 15:56 ` Suzuki K Poulose 2018-05-08 16:13 ` Mathieu Poirier 2018-05-08 16:13 ` Mathieu Poirier 2018-05-01 9:10 ` [PATCH v2 19/27] coresight: catu: Plug in CATU as a backend for ETR buffer Suzuki K Poulose 2018-05-01 9:10 ` Suzuki K Poulose 2018-05-07 22:02 ` Mathieu Poirier 2018-05-07 22:02 ` Mathieu Poirier 2018-05-08 16:21 ` Suzuki K Poulose 2018-05-08 16:21 ` Suzuki K Poulose 2018-05-01 9:10 ` [PATCH v2 20/27] coresight: tmc: Add configuration support for trace buffer size Suzuki K Poulose 2018-05-01 9:10 ` Suzuki K Poulose 2018-05-01 9:10 ` [PATCH v2 21/27] coresight: Convert driver messages to dev_dbg Suzuki K Poulose 2018-05-01 9:10 ` Suzuki K Poulose 2018-05-02 3:55 ` Kim Phillips 2018-05-02 3:55 ` Kim Phillips 2018-05-02 8:25 ` Robert Walker 2018-05-02 8:25 ` Robert Walker 2018-05-02 13:52 ` Robin Murphy 2018-05-02 13:52 ` Robin Murphy 2018-05-10 13:36 ` Suzuki K Poulose 2018-05-10 13:36 ` Suzuki K Poulose 2018-05-07 22:28 ` Mathieu Poirier 2018-05-07 22:28 ` Mathieu Poirier 2018-05-01 9:10 ` [PATCH v2 22/27] coresight: tmc-etr: Track if the device is coherent Suzuki K Poulose 2018-05-01 9:10 ` Suzuki K Poulose 2018-05-01 9:10 ` [PATCH v2 23/27] coresight: tmc-etr: Handle driver mode specific ETR buffers Suzuki K Poulose 2018-05-01 9:10 ` Suzuki K Poulose 2018-05-08 17:18 ` Mathieu Poirier 2018-05-08 17:18 ` Mathieu Poirier 2018-05-08 21:51 ` Suzuki K Poulose 2018-05-08 21:51 ` Suzuki K Poulose 2018-05-09 17:12 ` Mathieu Poirier 2018-05-09 17:12 ` Mathieu Poirier 2018-05-01 9:10 ` [PATCH v2 24/27] coresight: tmc-etr: Relax collection of trace from sysfs mode Suzuki K Poulose 2018-05-01 9:10 ` Suzuki K Poulose 2018-05-07 22:54 ` Mathieu Poirier 2018-05-07 22:54 ` Mathieu Poirier 2018-05-01 9:10 ` [PATCH v2 25/27] coresight: etr_buf: Add helper for padding an area of trace data Suzuki K Poulose 2018-05-01 9:10 ` Suzuki K Poulose 2018-05-08 17:34 ` Mathieu Poirier 2018-05-08 17:34 ` Mathieu Poirier 2018-05-01 9:10 ` [PATCH v2 26/27] coresight: perf: Remove reset_buffer call back for sinks Suzuki K Poulose 2018-05-01 9:10 ` Suzuki K Poulose 2018-05-08 19:42 ` Mathieu Poirier 2018-05-08 19:42 ` Mathieu Poirier 2018-05-11 16:35 ` Suzuki K Poulose 2018-05-11 16:35 ` Suzuki K Poulose 2018-05-01 9:10 ` [PATCH v2 27/27] coresight: etm-perf: Add support for ETR backend Suzuki K Poulose 2018-05-01 9:10 ` Suzuki K Poulose 2018-05-08 22:04 ` Mathieu Poirier 2018-05-08 22:04 ` Mathieu Poirier
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