Re: [PATCH v17 03/10] qcom-tgu: Add TGU driver

[Suzuki K Poulose <suzuki.poulose@arm.com>]

On 13/11/2026 02:49, Songwei Chai wrote:
> 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.
> 
> Acked-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
> Reviewed-by: Jie Gan <jie.gan@oss.qualcomm.com>
> Signed-off-by: Songwei Chai <songwei.chai@oss.qualcomm.com>
> ---
>   .../ABI/testing/sysfs-bus-amba-devices-tgu    |   9 +
>   MAINTAINERS                                   |  11 +
>   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                  |  31 +++
>   8 files changed, 270 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..66b12ffc2892
> --- /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:		November 2026
> +KernelVersion:	7.5
> +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/MAINTAINERS b/MAINTAINERS
> index fe23913b1e43..faf8706b6584 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -23264,6 +23264,17 @@ S:	Maintained
>   F:	Documentation/tee/qtee.rst
>   F:	drivers/tee/qcomtee/
>   
> +QUALCOMM HARDWARETRACING DRIVER

nit: HARDWARE TRACING DRIVER

> +M:	Songwei Chai <songwei.chai@oss.qualcomm.com>
> +M:	Jie Gan <jie.gan@oss.qualcomm.com>
> +M:	Suzuki K Poulose <suzuki.poulose@arm.com>
> +L:	linux-arm-msm@vger.kernel.org
> +S:	Maintained
> +T:	git git://git.kernel.org/pub/scm/linux/kernel/git/coresight/linux.git
> +F:	Documentation/ABI/testing/sysfs-bus-amba-devices-tgu
> +F:	Documentation/devicetree/bindings/arm/qcom,tgu.yaml
> +F:	drivers/hwtracing/qcom/
> +
>   QUALCOMM TRUST ZONE MEMORY ALLOCATOR
>   M:	Bartosz Golaszewski <brgl@kernel.org>
>   L:	linux-arm-msm@vger.kernel.org
> diff --git a/drivers/Makefile b/drivers/Makefile
> index 0841ea851847..f37edcf34e0d 100644
> --- a/drivers/Makefile
> +++ b/drivers/Makefile
> @@ -176,6 +176,7 @@ obj-$(CONFIG_RAS)		+= ras/
>   obj-$(CONFIG_USB4)		+= thunderbolt/
>   obj-$(CONFIG_CORESIGHT)		+= hwtracing/coresight/
>   obj-y				+= hwtracing/intel_th/
> +obj-$(CONFIG_QCOM_TGU)		+= 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..ac1ae8bb0ec4
> --- /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/coresight.h>
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/of.h>
> +#include <linux/pm_runtime.h>
> +
> +#include "tgu.h"

...

> +static ssize_t enable_tgu_show(struct device *dev,
> +			       struct device_attribute *attr, char *buf)
> +{

...

> +}
> +
> +/* enable_tgu_store - Enable or disable the Trigger Generation Unit (TGU). */
> +static ssize_t enable_tgu_store(struct device *dev,
> +				struct device_attribute *attr,
> +				const char *buf,
> +				size_t size)
> +{

...

> +}
> +static DEVICE_ATTR_RW(enable_tgu);

minor nit: Do we need "enable_tgu" in the name under /sys/.../tgu0/ ?
Couldn' this be "enable" ? Also, the function names could be named
as "tgu_enable_store/show"

Suzuki