[PATCH v14 2/7] qcom-tgu: Add TGU driver

[Songwei Chai <songwei.chai@oss.qualcomm.com>]

Add driver to support 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 <songwei.chai@oss.qualcomm.com>
Acked-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
---
 .../ABI/testing/sysfs-bus-amba-devices-tgu    |   9 +
 drivers/Makefile                              |   1 +
 drivers/hwtracing/Kconfig                     |   2 +
 drivers/hwtracing/qcom/Kconfig                |  20 ++
 drivers/hwtracing/qcom/Makefile               |   3 +
 drivers/hwtracing/qcom/tgu.c                  | 193 ++++++++++++++++++
 drivers/hwtracing/qcom/tgu.h                  |  51 +++++
 7 files changed, 279 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-bus-amba-devices-tgu
 create mode 100644 drivers/hwtracing/qcom/Kconfig
 create mode 100644 drivers/hwtracing/qcom/Makefile
 create mode 100644 drivers/hwtracing/qcom/tgu.c
 create mode 100644 drivers/hwtracing/qcom/tgu.h

diff --git a/Documentation/ABI/testing/sysfs-bus-amba-devices-tgu b/Documentation/ABI/testing/sysfs-bus-amba-devices-tgu
new file mode 100644
index 000000000000..f877a00fcaa5
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-amba-devices-tgu
@@ -0,0 +1,9 @@
+What:		/sys/bus/amba/devices/<tgu-name>/enable_tgu
+Date:		April 2026
+KernelVersion:	7.1
+Contact:	Jinlong Mao <jinlong.mao@oss.qualcomm.com>, Songwei Chai <songwei.chai@oss.qualcomm.com>
+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/Makefile b/drivers/Makefile
index 53fbd2e0acdd..82b712a12a26 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -177,6 +177,7 @@ obj-$(CONFIG_RAS)		+= ras/
 obj-$(CONFIG_USB4)		+= thunderbolt/
 obj-$(CONFIG_CORESIGHT)		+= hwtracing/coresight/
 obj-y				+= hwtracing/intel_th/
+obj-y				+= hwtracing/qcom/
 obj-$(CONFIG_STM)		+= hwtracing/stm/
 obj-$(CONFIG_HISI_PTT)		+= hwtracing/ptt/
 obj-y				+= android/
diff --git a/drivers/hwtracing/Kconfig b/drivers/hwtracing/Kconfig
index 911ee977103c..8a640218eed8 100644
--- a/drivers/hwtracing/Kconfig
+++ b/drivers/hwtracing/Kconfig
@@ -7,4 +7,6 @@ source "drivers/hwtracing/intel_th/Kconfig"
 
 source "drivers/hwtracing/ptt/Kconfig"
 
+source "drivers/hwtracing/qcom/Kconfig"
+
 endmenu
diff --git a/drivers/hwtracing/qcom/Kconfig b/drivers/hwtracing/qcom/Kconfig
new file mode 100644
index 000000000000..5c94c75ffa39
--- /dev/null
+++ b/drivers/hwtracing/qcom/Kconfig
@@ -0,0 +1,20 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# QCOM specific hwtracing drivers
+#
+menu "Qualcomm specific hwtracing drivers"
+
+config QCOM_TGU
+	tristate "QCOM Trigger Generation Unit driver"
+	depends on ARCH_QCOM || COMPILE_TEST
+	depends on ARM_AMBA
+	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.
+
+endmenu
diff --git a/drivers/hwtracing/qcom/Makefile b/drivers/hwtracing/qcom/Makefile
new file mode 100644
index 000000000000..5a0a868c1ea0
--- /dev/null
+++ b/drivers/hwtracing/qcom/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_QCOM_TGU) += tgu.o
diff --git a/drivers/hwtracing/qcom/tgu.c b/drivers/hwtracing/qcom/tgu.c
new file mode 100644
index 000000000000..49c8f710b931
--- /dev/null
+++ b/drivers/hwtracing/qcom/tgu.c
@@ -0,0 +1,193 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
+ */
+
+#include <linux/amba/bus.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 <linux/pm_runtime.h>
+
+#include "tgu.h"
+
+static void tgu_write_all_hw_regs(struct tgu_drvdata *drvdata)
+{
+	TGU_UNLOCK(drvdata->base);
+	/* Enable TGU to program the triggers */
+	writel(1, drvdata->base + TGU_CONTROL);
+	TGU_LOCK(drvdata->base);
+}
+
+static int tgu_enable(struct device *dev)
+{
+	struct tgu_drvdata *drvdata = dev_get_drvdata(dev);
+
+	guard(spinlock)(&drvdata->lock);
+	drvdata->enabled = true;
+
+	tgu_write_all_hw_regs(drvdata);
+
+	return 0;
+}
+
+static void tgu_do_disable(struct tgu_drvdata *drvdata)
+{
+	TGU_UNLOCK(drvdata->base);
+	writel(0, drvdata->base + TGU_CONTROL);
+	TGU_LOCK(drvdata->base);
+
+	drvdata->enabled = false;
+}
+
+static void tgu_disable(struct device *dev)
+{
+	struct tgu_drvdata *drvdata = dev_get_drvdata(dev);
+
+	guard(spinlock)(&drvdata->lock);
+	if (!drvdata->enabled)
+		return;
+
+	tgu_do_disable(drvdata);
+}
+
+static ssize_t enable_tgu_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	struct tgu_drvdata *drvdata = dev_get_drvdata(dev);
+	bool enabled;
+
+	guard(spinlock)(&drvdata->lock);
+	enabled = drvdata->enabled;
+
+	return sysfs_emit(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)
+{
+	struct tgu_drvdata *drvdata = dev_get_drvdata(dev);
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul(buf, 0, &val);
+	if (ret || val > 1)
+		return -EINVAL;
+
+	if (val) {
+		scoped_guard(spinlock, &drvdata->lock) {
+			if (drvdata->enabled)
+				return -EBUSY;
+		}
+
+		ret = pm_runtime_resume_and_get(dev);
+		if (ret)
+			return ret;
+
+		ret = tgu_enable(dev);
+		if (ret) {
+			pm_runtime_put(dev);
+			return ret;
+		}
+	} else {
+		scoped_guard(spinlock, &drvdata->lock) {
+			if (!drvdata->enabled)
+				return -EINVAL;
+		}
+
+		tgu_disable(dev);
+		pm_runtime_put(dev);
+	}
+
+	return size;
+}
+static DEVICE_ATTR_RW(enable_tgu);
+
+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)
+{
+	struct device *dev = &adev->dev;
+	struct tgu_drvdata *drvdata;
+	int ret;
+
+	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 (IS_ERR(drvdata->base))
+		return PTR_ERR(drvdata->base);
+
+	spin_lock_init(&drvdata->lock);
+
+	ret = sysfs_create_groups(&dev->kobj, tgu_attr_groups);
+	if (ret) {
+		dev_err(dev, "failed to create sysfs groups: %d\n", ret);
+		return ret;
+	}
+
+	drvdata->enabled = false;
+
+	pm_runtime_put(&adev->dev);
+
+	return 0;
+}
+
+static void tgu_remove(struct amba_device *adev)
+{
+	struct device *dev = &adev->dev;
+
+	sysfs_remove_groups(&dev->kobj, tgu_attr_groups);
+
+	tgu_disable(dev);
+}
+
+static const struct amba_id tgu_ids[] = {
+	{
+		.id = 0x000f0e00,
+		.mask = 0x000fffff,
+	},
+	{ 0, 0, NULL },
+};
+
+MODULE_DEVICE_TABLE(amba, tgu_ids);
+
+static struct amba_driver tgu_driver = {
+	.drv = {
+		.name = "qcom-tgu",
+		.suppress_bind_attrs = true,
+	},
+	.probe = tgu_probe,
+	.remove = tgu_remove,
+	.id_table = tgu_ids,
+};
+
+module_amba_driver(tgu_driver);
+
+MODULE_AUTHOR("Songwei Chai <songwei.chai@oss.qualcomm.com>");
+MODULE_AUTHOR("Jinlong Mao <jinlong.mao@oss.qualcomm.com>");
+MODULE_DESCRIPTION("Qualcomm Trigger Generation Unit driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/hwtracing/qcom/tgu.h b/drivers/hwtracing/qcom/tgu.h
new file mode 100644
index 000000000000..dd7533b9d735
--- /dev/null
+++ b/drivers/hwtracing/qcom/tgu.h
@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
+ */
+
+#ifndef _QCOM_TGU_H
+#define _QCOM_TGU_H
+
+/* Register addresses */
+#define TGU_CONTROL		0x0000
+#define TGU_LAR		0xfb0
+#define TGU_UNLOCK_OFFSET	0xc5acce55
+
+static inline void TGU_LOCK(void __iomem *addr)
+{
+	do {
+		/* Wait for things to settle */
+		mb();
+		writel_relaxed(0x0, addr + TGU_LAR);
+	} while (0);
+}
+
+static inline void TGU_UNLOCK(void __iomem *addr)
+{
+	do {
+		writel_relaxed(TGU_UNLOCK_OFFSET, addr + TGU_LAR);
+		/* Make sure everyone has seen this */
+		mb();
+	} while (0);
+}
+
+/**
+ * struct tgu_drvdata - Data structure for a TGU (Trigger Generator Unit)
+ * @base: Memory-mapped base address of the TGU device
+ * @dev: Pointer to the associated device structure
+ * @lock: Spinlock for handling concurrent access to private data
+ * @enabled: 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;
+	spinlock_t lock;
+	bool enabled;
+};
+
+#endif
-- 
2.34.1