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Message-ID: <CAJ9a7Vip6Dda1q7R_LoQjB4696Yi3iDv6512Vsy6aqdpiPTWgw@mail.gmail.com>
Date: Thu, 6 Mar 2025 16:57:35 +0000
From: Mike Leach <mike.leach@...aro.org>
To: songchai <quic_songchai@...cinc.com>
Cc: Suzuki K Poulose <suzuki.poulose@....com>, James Clark <james.clark@....com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Andy Gross <agross@...nel.org>,
Bjorn Andersson <andersson@...nel.org>, Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, linux-kernel@...r.kernel.org,
coresight@...ts.linaro.org, linux-arm-kernel@...ts.infradead.org,
linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org
Subject: Re: [PATCH v3 2/7] coresight: Add coresight TGU driver
Hi,
On Thu, 27 Feb 2025 at 09:27, songchai <quic_songchai@...cinc.com> wrote:
>
> From: Songwei Chai <quic_songchai@...cinc.com>
>
> 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@...cinc.com>
> Signed-off-by: songchai <quic_songchai@...cinc.com>
> ---
> .../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..741bc9fd9df5
> --- /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: February 2025
> +KernelVersion 6.15
> +Contact: Jinlong Mao (QUIC) <quic_jinlmao@...cinc.com>, Sam Chai (QUIC) <quic_songchai@...cinc.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/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..da4c04ac1097
> --- /dev/null
> +++ b/drivers/hwtracing/coresight/coresight-tgu.c
> @@ -0,0 +1,218 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2024-2025 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) {
Could simplify by changing logic here -
if (enable) { do disable stuff }
and have a single return point
> + 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);
sysfs_emit() should be used here.
> +}
> +
> +/* 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)
redundant - tgu_disable always returns 0.
> + 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..380686f94130
> --- /dev/null
> +++ b/drivers/hwtracing/coresight/coresight-tgu.h
> @@ -0,0 +1,36 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (c) 2024-2025 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,
I don't see any trigger data pointers or limits here. Comment on what
is there, if more is added later, expand the comment later.
> + * 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
>
Regards
Mike
--
Mike Leach
Principal Engineer, ARM Ltd.
Manchester Design Centre. UK
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