Re: [PATCH v3 2/7] coresight: Add coresight TGU driver

Hi,

On Thu, 27 Feb 2025 at 09:27, songchai quic_songchai@quicinc.com wrote:

From: Songwei Chai quic_songchai@quicinc.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@quicinc.com Signed-off-by: songchai quic_songchai@quicinc.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@quicinc.com, Sam Chai (QUIC) quic_songchai@quicinc.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