[PATCHv3 0/2] Add support for replicators which loses context on clock removal

[PATCHv3 0/2] Add support for replicators which loses context on clock removal

[Sai Prakash Ranjan]

This series is mainly to add support for replicators
which lose context on removing AMBA clock like on SC7180
SoC where replicator in AOSS domain loses context.

v2 - https://lore.kernel.org/patchwork/cover/1244340/
More discussion is found here - https://lore.kernel.org/patchwork/patch/1231182/

Changes since v2:
 * Added DT maintainers which I missed in v2
 * Added proper kernel-doc and header as per Mathieu

Sai Prakash Ranjan (2):
  coresight: replicator: Reset replicator if context is lost
  dt-bindings: arm: coresight: Add optional property to replicators

 .../devicetree/bindings/arm/coresight.txt     |  6 ++
 .../coresight/coresight-replicator.c          | 55 +++++++++++++------
 2 files changed, 44 insertions(+), 17 deletions(-)

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[PATCHv3 1/2] coresight: replicator: Reset replicator if context is lost

[Sai Prakash Ranjan]

On some QCOM SoCs, replicators in Always-On domain loses its
context as soon as the clock is disabled. Currently as a part
of pm_runtime workqueue, clock is disabled after the replicator
is initialized by amba_pm_runtime_suspend assuming that context
is not lost which is not true for replicators with such
limitations. So add a new property "qcom,replicator-loses-context"
to identify such replicators and reset them.

Suggested-by: Mike Leach <mike.leach@linaro.org>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
---
 .../coresight/coresight-replicator.c          | 55 +++++++++++++------
 1 file changed, 38 insertions(+), 17 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-replicator.c b/drivers/hwtracing/coresight/coresight-replicator.c
index e7dc1c31d20d..9d3a8f915784 100644
--- a/drivers/hwtracing/coresight/coresight-replicator.c
+++ b/drivers/hwtracing/coresight/coresight-replicator.c
@@ -14,6 +14,7 @@
 #include <linux/err.h>
 #include <linux/slab.h>
 #include <linux/pm_runtime.h>
+#include <linux/property.h>
 #include <linux/clk.h>
 #include <linux/of.h>
 #include <linux/coresight.h>
@@ -32,12 +33,14 @@ DEFINE_CORESIGHT_DEVLIST(replicator_devs, "replicator");
  * @atclk:	optional clock for the core parts of the replicator.
  * @csdev:	component vitals needed by the framework
  * @spinlock:	serialize enable/disable operations.
+ * @check_idfilter_val: check if the context is lost upon clock removal.
  */
 struct replicator_drvdata {
 	void __iomem		*base;
 	struct clk		*atclk;
 	struct coresight_device	*csdev;
 	spinlock_t		spinlock;
+	bool			check_idfilter_val;
 };
 
 static void dynamic_replicator_reset(struct replicator_drvdata *drvdata)
@@ -66,29 +69,43 @@ static int dynamic_replicator_enable(struct replicator_drvdata *drvdata,
 				     int inport, int outport)
 {
 	int rc = 0;
-	u32 reg;
-
-	switch (outport) {
-	case 0:
-		reg = REPLICATOR_IDFILTER0;
-		break;
-	case 1:
-		reg = REPLICATOR_IDFILTER1;
-		break;
-	default:
-		WARN_ON(1);
-		return -EINVAL;
-	}
+	u32 id0val, id1val;
 
 	CS_UNLOCK(drvdata->base);
 
-	if ((readl_relaxed(drvdata->base + REPLICATOR_IDFILTER0) == 0xff) &&
-	    (readl_relaxed(drvdata->base + REPLICATOR_IDFILTER1) == 0xff))
+	id0val = readl_relaxed(drvdata->base + REPLICATOR_IDFILTER0);
+	id1val = readl_relaxed(drvdata->base + REPLICATOR_IDFILTER1);
+
+	/*
+	 * Some replicator designs lose context when AMBA clocks are removed,
+	 * so have a check for this.
+	 */
+	if (drvdata->check_idfilter_val && id0val == 0x0 && id1val == 0x0)
+		id0val = id1val = 0xff;
+
+	if (id0val == 0xff && id1val == 0xff)
 		rc = coresight_claim_device_unlocked(drvdata->base);
 
+	if (!rc) {
+		switch (outport) {
+		case 0:
+			id0val = 0x0;
+			break;
+		case 1:
+			id1val = 0x0;
+			break;
+		default:
+			WARN_ON(1);
+			rc = -EINVAL;
+		}
+	}
+
 	/* Ensure that the outport is enabled. */
-	if (!rc)
-		writel_relaxed(0x00, drvdata->base + reg);
+	if (!rc) {
+		writel_relaxed(id0val, drvdata->base + REPLICATOR_IDFILTER0);
+		writel_relaxed(id1val, drvdata->base + REPLICATOR_IDFILTER1);
+	}
+
 	CS_LOCK(drvdata->base);
 
 	return rc;
@@ -239,6 +256,10 @@ static int replicator_probe(struct device *dev, struct resource *res)
 		desc.groups = replicator_groups;
 	}
 
+	if (fwnode_property_present(dev_fwnode(dev),
+				    "qcom,replicator-loses-context"))
+		drvdata->check_idfilter_val = true;
+
 	dev_set_drvdata(dev, drvdata);
 
 	pdata = coresight_get_platform_data(dev);
-- 
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[PATCHv3 2/2] dt-bindings: arm: coresight: Add optional property to replicators

[Sai Prakash Ranjan]

Add an optional boolean property "qcom,replicator-loses-context" to
identify replicators which loses context when AMBA clocks are removed
in certain configurable replicator designs.

Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
---
 Documentation/devicetree/bindings/arm/coresight.txt | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/devicetree/bindings/arm/coresight.txt b/Documentation/devicetree/bindings/arm/coresight.txt
index 846f6daae71b..b598a5f0037d 100644
--- a/Documentation/devicetree/bindings/arm/coresight.txt
+++ b/Documentation/devicetree/bindings/arm/coresight.txt
@@ -121,6 +121,12 @@ its hardware characteristcs.
 	* interrupts : Exactly one SPI may be listed for reporting the address
 	  error
 
+* Optional property for configurable replicators:
+
+	* qcom,replicator-loses-context: boolean. Indicates that the replicator
+	  will lose register context when AMBA clock is removed which is observed
+	  in some replicator designs.
+
 Graph bindings for Coresight
 -------------------------------
 
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Re: [PATCHv3 2/2] dt-bindings: arm: coresight: Add optional property to replicators

[Mathieu Poirier]

On Fri, 22 May 2020 at 12:37, Sai Prakash Ranjan
<saiprakash.ranjan@codeaurora.org> wrote:
>
> Add an optional boolean property "qcom,replicator-loses-context" to
> identify replicators which loses context when AMBA clocks are removed
> in certain configurable replicator designs.
>
> Reviewed-by: Mike Leach <mike.leach@linaro.org>
> Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
> ---
>  Documentation/devicetree/bindings/arm/coresight.txt | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/arm/coresight.txt b/Documentation/devicetree/bindings/arm/coresight.txt
> index 846f6daae71b..b598a5f0037d 100644
> --- a/Documentation/devicetree/bindings/arm/coresight.txt
> +++ b/Documentation/devicetree/bindings/arm/coresight.txt
> @@ -121,6 +121,12 @@ its hardware characteristcs.
>         * interrupts : Exactly one SPI may be listed for reporting the address
>           error
>
> +* Optional property for configurable replicators:
> +
> +       * qcom,replicator-loses-context: boolean. Indicates that the replicator
> +         will lose register context when AMBA clock is removed which is observed
> +         in some replicator designs.

Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>

> +
>  Graph bindings for Coresight
>  -------------------------------
>
> --
> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
> of Code Aurora Forum, hosted by The Linux Foundation
>

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Re: [PATCHv3 0/2] Add support for replicators which loses context on clock removal

[Mathieu Poirier]

Hi Sai,

On Sat, May 23, 2020 at 12:06:50AM +0530, Sai Prakash Ranjan wrote:
> This series is mainly to add support for replicators
> which lose context on removing AMBA clock like on SC7180
> SoC where replicator in AOSS domain loses context.
> 

I am good with this set but need a reviewed-by on the DT binding before I can
add it to my tree.  The same goes for your other set[1].

Thanks,
Mathieu

[1]. "coresight: etm4x: Add support to skip trace unit power up"

> v2 - https://lore.kernel.org/patchwork/cover/1244340/
> More discussion is found here - https://lore.kernel.org/patchwork/patch/1231182/
> 
> Changes since v2:
>  * Added DT maintainers which I missed in v2
>  * Added proper kernel-doc and header as per Mathieu
> 
> Sai Prakash Ranjan (2):
>   coresight: replicator: Reset replicator if context is lost
>   dt-bindings: arm: coresight: Add optional property to replicators
> 
>  .../devicetree/bindings/arm/coresight.txt     |  6 ++
>  .../coresight/coresight-replicator.c          | 55 +++++++++++++------
>  2 files changed, 44 insertions(+), 17 deletions(-)
> 
> -- 
> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
> of Code Aurora Forum, hosted by The Linux Foundation
> 

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Re: [PATCHv3 0/2] Add support for replicators which loses context on clock removal

[Sai Prakash Ranjan]

Hi Mathieu,

On 2020-05-25 21:45, Mathieu Poirier wrote:
> Hi Sai,
> 
> On Sat, May 23, 2020 at 12:06:50AM +0530, Sai Prakash Ranjan wrote:
>> This series is mainly to add support for replicators
>> which lose context on removing AMBA clock like on SC7180
>> SoC where replicator in AOSS domain loses context.
>> 
> 
> I am good with this set but need a reviewed-by on the DT binding before 
> I can
> add it to my tree.  The same goes for your other set[1].
> 

Sure, let's wait for an ack from Rob and thanks for the reviews.

Thanks,
Sai

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Re: [PATCHv3 0/2] Add support for replicators which loses context on clock removal

[Rob Herring]

On Mon, May 25, 2020 at 10:15:53AM -0600, Mathieu Poirier wrote:
> Hi Sai,
> 
> On Sat, May 23, 2020 at 12:06:50AM +0530, Sai Prakash Ranjan wrote:
> > This series is mainly to add support for replicators
> > which lose context on removing AMBA clock like on SC7180
> > SoC where replicator in AOSS domain loses context.
> > 
> 
> I am good with this set but need a reviewed-by on the DT binding before I can
> add it to my tree.  The same goes for your other set[1].

Then why is it already in linux-next?

In any case,

Acked-by: Rob Herring <robh@kernel.org>

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Re: [PATCHv3 0/2] Add support for replicators which loses context on clock removal

[Mathieu Poirier]

On Thu, May 28, 2020 at 08:48:03AM -0600, Rob Herring wrote:
> On Mon, May 25, 2020 at 10:15:53AM -0600, Mathieu Poirier wrote:
> > Hi Sai,
> > 
> > On Sat, May 23, 2020 at 12:06:50AM +0530, Sai Prakash Ranjan wrote:
> > > This series is mainly to add support for replicators
> > > which lose context on removing AMBA clock like on SC7180
> > > SoC where replicator in AOSS domain loses context.
> > > 
> > 
> > I am good with this set but need a reviewed-by on the DT binding before I can
> > add it to my tree.  The same goes for your other set[1].
> 
> Then why is it already in linux-next?

I wanted the patches to get exposure to linux-next before sending them on to
Greg for inclusion in the next merge window.  Rest assured that I would not have
moved forward without your consent.

> 
> In any case,
> 
> Acked-by: Rob Herring <robh@kernel.org>

Thank you for that.

Mathieu

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