coresight: replicator: Add Qualcomm CoreSight Replicator driver

This driver manages Qualcomm CoreSight Replicator device, which
resides on the AMBA bus. Replicator has been made programmable to
allow software to turn of the replicator branch to sink that is not
being used. This avoids trace traffic to the unused/non-current sink
from causing back pressure that results in overflows at the source.

Signed-off-by: Pratik Patel <pratikp@codeaurora.org>
Signed-off-by: Ivan T. Ivanov <ivan.ivanov@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/arm/coresight.txt

@@ -17,6 +17,7 @@ its hardware characteristcs.
 		- "arm,coresight-tmc", "arm,primecell";
 		- "arm,coresight-funnel", "arm,primecell";
 		- "arm,coresight-etm3x", "arm,primecell";
+		- "qcom,coresight-replicator1x", "arm,primecell";
 
 	* reg: physical base address and length of the register
 	  set(s) of the component.

drivers/hwtracing/coresight/Kconfig

@@ -69,4 +69,12 @@ config CORESIGHT_SOURCE_ETM4X
 	  for instruction level tracing. Depending on the implemented version
 	  data tracing may also be available.
 
+config CORESIGHT_QCOM_REPLICATOR
+	bool "Qualcomm CoreSight Replicator driver"
+	depends on CORESIGHT_LINKS_AND_SINKS
+	help
+	  This enables support for Qualcomm CoreSight link driver. The
+	  programmable ATB replicator sends the ATB trace stream from the
+	  ETB/ETF to the TPIUi and ETR.
+
 endif

drivers/hwtracing/coresight/Makefile

@@ -10,3 +10,4 @@ obj-$(CONFIG_CORESIGHT_LINKS_AND_SINKS) += coresight-funnel.o \
 					   coresight-replicator.o
 obj-$(CONFIG_CORESIGHT_SOURCE_ETM3X) += coresight-etm3x.o coresight-etm-cp14.o
 obj-$(CONFIG_CORESIGHT_SOURCE_ETM4X) += coresight-etm4x.o
+obj-$(CONFIG_CORESIGHT_QCOM_REPLICATOR) += coresight-replicator-qcom.o

drivers/hwtracing/coresight/coresight-replicator-qcom.c

@@ -0,0 +1,214 @@
+/*
+ * Copyright (c) 2011-2015, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/amba/bus.h>
+#include <linux/clk.h>
+#include <linux/coresight.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/pm_runtime.h>
+#include <linux/slab.h>
+
+#include "coresight-priv.h"
+
+#define REPLICATOR_IDFILTER0		0x000
+#define REPLICATOR_IDFILTER1		0x004
+
+/**
+ * struct replicator_state - specifics associated to a replicator component
+ * @base:	memory mapped base address for this component.
+ * @dev:	the device entity associated with this component
+ * @atclk:	optional clock for the core parts of the replicator.
+ * @csdev:	component vitals needed by the framework
+ */
+struct replicator_state {
+	void __iomem		*base;
+	struct device		*dev;
+	struct clk		*atclk;
+	struct coresight_device	*csdev;
+};
+
+static int replicator_enable(struct coresight_device *csdev, int inport,
+			      int outport)
+{
+	struct replicator_state *drvdata = dev_get_drvdata(csdev->dev.parent);
+
+	pm_runtime_get_sync(drvdata->dev);
+
+	CS_UNLOCK(drvdata->base);
+
+	/*
+	 * Ensure that the other port is disabled
+	 * 0x00 - passing through the replicator unimpeded
+	 * 0xff - disable (or impede) the flow of ATB data
+	 */
+	if (outport == 0) {
+		writel_relaxed(0x00, drvdata->base + REPLICATOR_IDFILTER0);
+		writel_relaxed(0xff, drvdata->base + REPLICATOR_IDFILTER1);
+	} else {
+		writel_relaxed(0x00, drvdata->base + REPLICATOR_IDFILTER1);
+		writel_relaxed(0xff, drvdata->base + REPLICATOR_IDFILTER0);
+	}
+
+	CS_LOCK(drvdata->base);
+
+	dev_info(drvdata->dev, "REPLICATOR enabled\n");
+	return 0;
+}
+
+static void replicator_disable(struct coresight_device *csdev, int inport,
+				int outport)
+{
+	struct replicator_state *drvdata = dev_get_drvdata(csdev->dev.parent);
+
+	CS_UNLOCK(drvdata->base);
+
+	/* disable the flow of ATB data through port */
+	if (outport == 0)
+		writel_relaxed(0xff, drvdata->base + REPLICATOR_IDFILTER0);
+	else
+		writel_relaxed(0xff, drvdata->base + REPLICATOR_IDFILTER1);
+
+	CS_LOCK(drvdata->base);
+
+	pm_runtime_put(drvdata->dev);
+
+	dev_info(drvdata->dev, "REPLICATOR disabled\n");
+}
+
+static const struct coresight_ops_link replicator_link_ops = {
+	.enable		= replicator_enable,
+	.disable	= replicator_disable,
+};
+
+static const struct coresight_ops replicator_cs_ops = {
+	.link_ops	= &replicator_link_ops,
+};
+
+static int replicator_probe(struct amba_device *adev, const struct amba_id *id)
+{
+	int ret;
+	struct device *dev = &adev->dev;
+	struct resource *res = &adev->res;
+	struct coresight_platform_data *pdata = NULL;
+	struct replicator_state *drvdata;
+	struct coresight_desc *desc;
+	struct device_node *np = adev->dev.of_node;
+	void __iomem *base;
+
+	if (np) {
+		pdata = of_get_coresight_platform_data(dev, np);
+		if (IS_ERR(pdata))
+			return PTR_ERR(pdata);
+		adev->dev.platform_data = pdata;
+	}
+
+	drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
+	if (!drvdata)
+		return -ENOMEM;
+
+	drvdata->dev = &adev->dev;
+	drvdata->atclk = devm_clk_get(&adev->dev, "atclk"); /* optional */
+	if (!IS_ERR(drvdata->atclk)) {
+		ret = clk_prepare_enable(drvdata->atclk);
+		if (ret)
+			return ret;
+	}
+
+	/* Validity for the resource is already checked by the AMBA core */
+	base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	drvdata->base = base;
+	dev_set_drvdata(dev, drvdata);
+	pm_runtime_put(&adev->dev);
+
+	desc = devm_kzalloc(dev, sizeof(*desc), GFP_KERNEL);
+	if (!desc)
+		return -ENOMEM;
+
+	desc->type = CORESIGHT_DEV_TYPE_LINK;
+	desc->subtype.link_subtype = CORESIGHT_DEV_SUBTYPE_LINK_SPLIT;
+	desc->ops = &replicator_cs_ops;
+	desc->pdata = adev->dev.platform_data;
+	desc->dev = &adev->dev;
+	drvdata->csdev = coresight_register(desc);
+	if (IS_ERR(drvdata->csdev))
+		return PTR_ERR(drvdata->csdev);
+
+	dev_info(dev, "%s initialized\n", (char *)id->data);
+	return 0;
+}
+
+static int replicator_remove(struct amba_device *adev)
+{
+	struct replicator_state *drvdata = amba_get_drvdata(adev);
+
+	pm_runtime_disable(&adev->dev);
+	coresight_unregister(drvdata->csdev);
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int replicator_runtime_suspend(struct device *dev)
+{
+	struct replicator_state *drvdata = dev_get_drvdata(dev);
+
+	if (drvdata && !IS_ERR(drvdata->atclk))
+		clk_disable_unprepare(drvdata->atclk);
+
+	return 0;
+}
+
+static int replicator_runtime_resume(struct device *dev)
+{
+	struct replicator_state *drvdata = dev_get_drvdata(dev);
+
+	if (drvdata && !IS_ERR(drvdata->atclk))
+		clk_prepare_enable(drvdata->atclk);
+
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops replicator_dev_pm_ops = {
+	SET_RUNTIME_PM_OPS(replicator_runtime_suspend,
+			   replicator_runtime_resume,
+			   NULL)
+};
+
+static struct amba_id replicator_ids[] = {
+	{
+		.id     = 0x0003b909,
+		.mask   = 0x0003ffff,
+		.data	= "REPLICATOR 1.0",
+	},
+	{ 0, 0 },
+};
+
+static struct amba_driver replicator_driver = {
+	.drv = {
+		.name	= "coresight-replicator-qcom",
+		.pm	= &replicator_dev_pm_ops,
+	},
+	.probe		= replicator_probe,
+	.remove		= replicator_remove,
+	.id_table	= replicator_ids,
+};
+
+module_amba_driver(replicator_driver);