[PATCH v2 2/7] coresight: Add coresight TGU driver

[Songwei Chai]

Add driver to support Coresight device TGU (Trigger Generation Unit).
TGU is a Data Engine which can be utilized to sense a plurality of
signals and create a trigger into the CTI or generate interrupts to
processors. Add probe/enable/disable functions for tgu.

Signed-off-by: Songwei Chai <quic_songchai@xxxxxxxxxxx>
---
 .../testing/sysfs-bus-coresight-devices-tgu   |   9 +
 drivers/hwtracing/coresight/Kconfig           |  11 +
 drivers/hwtracing/coresight/Makefile          |   1 +
 drivers/hwtracing/coresight/coresight-tgu.c   | 218 ++++++++++++++++++
 drivers/hwtracing/coresight/coresight-tgu.h   |  36 +++
 5 files changed, 275 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-bus-coresight-devices-tgu
 create mode 100644 drivers/hwtracing/coresight/coresight-tgu.c
 create mode 100644 drivers/hwtracing/coresight/coresight-tgu.h

diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tgu b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tgu
new file mode 100644
index 000000000000..ee976b67ff01
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tgu
@@ -0,0 +1,9 @@
+What:		/sys/bus/coresight/devices/<tgu-name>/enable_tgu
+Date:		August 2024
+KernelVersion	6.10
+Contact:	Jinlong Mao (QUIC) <quic_jinlmao@xxxxxxxxxxx>, Sam Chai (QUIC) <quic_songchai@xxxxxxxxxxx>
+Description:
+		(RW) Set/Get the enable/disable status of TGU
+		Accepts only one of the 2 values -  0 or 1.
+		0 : disable TGU.
+		1 : enable TGU.
diff --git a/drivers/hwtracing/coresight/Kconfig b/drivers/hwtracing/coresight/Kconfig
index 06f0a7594169..3fe59c745dd4 100644
--- a/drivers/hwtracing/coresight/Kconfig
+++ b/drivers/hwtracing/coresight/Kconfig
@@ -247,4 +247,15 @@ config CORESIGHT_DUMMY
 
 	  To compile this driver as a module, choose M here: the module will be
 	  called coresight-dummy.
+
+config CORESIGHT_TGU
+	tristate "CoreSight Trigger Generation Unit driver"
+	help
+	  This driver provides support for Trigger Generation Unit that is
+	  used to detect patterns or sequences on a given set of signals.
+	  TGU is used to monitor a particular bus within a given region to
+	  detect illegal transaction sequences or slave responses. It is also
+	  used to monitor a data stream to detect protocol violations and to
+	  provide a trigger point for centering data around a specific event
+	  within the trace data buffer.
 endif
diff --git a/drivers/hwtracing/coresight/Makefile b/drivers/hwtracing/coresight/Makefile
index 4ba478211b31..7c2b9e9cf1cd 100644
--- a/drivers/hwtracing/coresight/Makefile
+++ b/drivers/hwtracing/coresight/Makefile
@@ -51,3 +51,4 @@ coresight-cti-y := coresight-cti-core.o	coresight-cti-platform.o \
 		   coresight-cti-sysfs.o
 obj-$(CONFIG_ULTRASOC_SMB) += ultrasoc-smb.o
 obj-$(CONFIG_CORESIGHT_DUMMY) += coresight-dummy.o
+obj-$(CONFIG_CORESIGHT_TGU) += coresight-tgu.o
diff --git a/drivers/hwtracing/coresight/coresight-tgu.c b/drivers/hwtracing/coresight/coresight-tgu.c
new file mode 100644
index 000000000000..1a196c90a973
--- /dev/null
+++ b/drivers/hwtracing/coresight/coresight-tgu.c
@@ -0,0 +1,218 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2024 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#include <linux/amba/bus.h>
+#include <linux/coresight.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+
+#include "coresight-priv.h"
+#include "coresight-tgu.h"
+
+DEFINE_CORESIGHT_DEVLIST(tgu_devs, "tgu");
+
+static void tgu_write_all_hw_regs(struct tgu_drvdata *drvdata)
+{
+	CS_UNLOCK(drvdata->base);
+	/* Enable TGU to program the triggers */
+	tgu_writel(drvdata, 1, TGU_CONTROL);
+	CS_LOCK(drvdata->base);
+}
+
+static int tgu_enable(struct coresight_device *csdev, enum cs_mode mode,
+		      void *data)
+{
+	struct tgu_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+
+	spin_lock(&drvdata->spinlock);
+
+	if (drvdata->enable) {
+		spin_unlock(&drvdata->spinlock);
+		return -EBUSY;
+	}
+	tgu_write_all_hw_regs(drvdata);
+	drvdata->enable = true;
+
+	spin_unlock(&drvdata->spinlock);
+	return 0;
+}
+
+static int tgu_disable(struct coresight_device *csdev, void *data)
+{
+	struct tgu_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+
+	spin_lock(&drvdata->spinlock);
+
+	if (!drvdata->enable) {
+		spin_unlock(&drvdata->spinlock);
+		return 0;
+	}
+
+	CS_UNLOCK(drvdata->base);
+	tgu_writel(drvdata, 0, TGU_CONTROL);
+	CS_LOCK(drvdata->base);
+
+	drvdata->enable = false;
+	spin_unlock(&drvdata->spinlock);
+	return 0;
+}
+
+static ssize_t enable_tgu_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	bool enabled;
+
+	struct tgu_drvdata *drvdata = dev_get_drvdata(dev->parent);
+
+	spin_lock(&drvdata->spinlock);
+	enabled = drvdata->enable;
+	spin_unlock(&drvdata->spinlock);
+
+	return sprintf(buf, "%d\n", enabled);
+}
+
+/* enable_tgu_store - Configure Trace and Gating Unit (TGU) triggers. */
+static ssize_t enable_tgu_store(struct device *dev,
+				struct device_attribute *attr, const char *buf,
+				size_t size)
+{
+	int ret = 0;
+	unsigned long val;
+	struct tgu_drvdata *drvdata = dev_get_drvdata(dev->parent);
+
+	ret = kstrtoul(buf, 0, &val);
+	if (ret)
+		return ret;
+
+	if (val) {
+		ret = pm_runtime_resume_and_get(dev->parent);
+		if (ret)
+			return ret;
+		ret = tgu_enable(drvdata->csdev, CS_MODE_SYSFS, NULL);
+		if (ret)
+			pm_runtime_put(dev->parent);
+	} else {
+		ret = tgu_disable(drvdata->csdev, NULL);
+		if (!ret)
+			pm_runtime_put(dev->parent);
+	}
+
+	if (ret)
+		return ret;
+	return size;
+}
+static DEVICE_ATTR_RW(enable_tgu);
+
+static const struct coresight_ops_helper tgu_helper_ops = {
+	.enable = tgu_enable,
+	.disable = tgu_disable,
+};
+
+static const struct coresight_ops tgu_ops = {
+	.helper_ops = &tgu_helper_ops,
+};
+
+static struct attribute *tgu_common_attrs[] = {
+	&dev_attr_enable_tgu.attr,
+	NULL,
+};
+
+static const struct attribute_group tgu_common_grp = {
+	.attrs = tgu_common_attrs,
+	NULL,
+};
+
+static const struct attribute_group *tgu_attr_groups[] = {
+	&tgu_common_grp,
+	NULL,
+};
+
+static int tgu_probe(struct amba_device *adev, const struct amba_id *id)
+{
+	int ret = 0;
+	struct device *dev = &adev->dev;
+	struct coresight_desc desc = { 0 };
+	struct coresight_platform_data *pdata;
+	struct tgu_drvdata *drvdata;
+
+	desc.name = coresight_alloc_device_name(&tgu_devs, dev);
+	if (!desc.name)
+		return -ENOMEM;
+
+	pdata = coresight_get_platform_data(dev);
+	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;
+	dev_set_drvdata(dev, drvdata);
+
+	drvdata->base = devm_ioremap_resource(dev, &adev->res);
+	if (!drvdata->base)
+		return -ENOMEM;
+
+	spin_lock_init(&drvdata->spinlock);
+
+	drvdata->enable = false;
+	desc.type = CORESIGHT_DEV_TYPE_HELPER;
+	desc.pdata = adev->dev.platform_data;
+	desc.dev = &adev->dev;
+	desc.ops = &tgu_ops;
+	desc.groups = tgu_attr_groups;
+
+	drvdata->csdev = coresight_register(&desc);
+	if (IS_ERR(drvdata->csdev)) {
+		ret = PTR_ERR(drvdata->csdev);
+		goto err;
+	}
+
+	pm_runtime_put(&adev->dev);
+	return 0;
+err:
+	pm_runtime_put(&adev->dev);
+	return ret;
+}
+
+static void tgu_remove(struct amba_device *adev)
+{
+	struct tgu_drvdata *drvdata = dev_get_drvdata(&adev->dev);
+
+	coresight_unregister(drvdata->csdev);
+}
+
+static const struct amba_id tgu_ids[] = {
+	{
+		.id = 0x000f0e00,
+		.mask = 0x000fffff,
+		.data = "TGU",
+	},
+	{ 0, 0, NULL },
+};
+
+MODULE_DEVICE_TABLE(amba, tgu_ids);
+
+static struct amba_driver tgu_driver = {
+	.drv = {
+		.name = "coresight-tgu",
+		.suppress_bind_attrs = true,
+	},
+	.probe	= tgu_probe,
+	.remove	= tgu_remove,
+	.id_table	= tgu_ids,
+};
+
+module_amba_driver(tgu_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("CoreSight TGU driver");
diff --git a/drivers/hwtracing/coresight/coresight-tgu.h b/drivers/hwtracing/coresight/coresight-tgu.h
new file mode 100644
index 000000000000..6e793421066b
--- /dev/null
+++ b/drivers/hwtracing/coresight/coresight-tgu.h
@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#ifndef _CORESIGHT_TGU_H
+#define _CORESIGHT_TGU_H
+
+/* Register addresses */
+#define TGU_CONTROL 0x0000
+
+/* Register read/write */
+#define tgu_writel(drvdata, val, off) __raw_writel((val), drvdata->base + off)
+#define tgu_readl(drvdata, off) __raw_readl(drvdata->base + off)
+
+/**
+ * struct tgu_drvdata - Data structure for a TGU (Trigger Generator Unit) device
+ * @base: Memory-mapped base address of the TGU device
+ * @dev: Pointer to the associated device structure
+ * @csdev: Pointer to the associated coresight device
+ * @spinlock: Spinlock for handling concurrent access
+ * @enable: Flag indicating whether the TGU device is enabled
+ *
+ * This structure defines the data associated with a TGU device, including its base
+ * address, device pointers, clock, spinlock for synchronization, trigger data pointers,
+ * maximum limits for various trigger-related parameters, and enable status.
+ */
+struct tgu_drvdata {
+	void __iomem *base;
+	struct device *dev;
+	struct coresight_device *csdev;
+	spinlock_t spinlock;
+	bool enable;
+};
+
+#endif