On 10/03/2026 03:01, Jie Gan wrote:
On 3/9/2026 8:43 PM, Suzuki K Poulose wrote:
On 09/03/2026 09:47, Jie Gan wrote:
The byte-cntr function provided by the CTCU device is used to transfer data from the ETR buffer to the userspace. An interrupt is triggered if the data size exceeds the threshold set in the BYTECNTRVAL register. The interrupt handler counts the number of triggered interruptions and the read function will read the data from the synced ETR buffer.
Switching the sysfs_buf when current buffer is full or the timeout is triggered and resets rrp and rwp registers after switched the buffer. The synced buffer will become available for reading after the switch.
Signed-off-by: Jie Gan jie.gan@oss.qualcomm.com
.../ABI/testing/sysfs-bus-coresight-devices-ctcu | 8 + drivers/hwtracing/coresight/Makefile | 2 +- .../hwtracing/coresight/coresight-ctcu-byte-cntr.c | 351 ++++++++++
- ++++++++++
drivers/hwtracing/coresight/coresight-ctcu-core.c | 103 +++++- drivers/hwtracing/coresight/coresight-ctcu.h | 76 ++++- drivers/hwtracing/coresight/coresight-tmc-core.c | 8 +- drivers/hwtracing/coresight/coresight-tmc-etr.c | 18 ++ drivers/hwtracing/coresight/coresight-tmc.h | 4 + 8 files changed, 555 insertions(+), 15 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices- ctcu b/Documentation/ABI/testing/sysfs-bus-coresight-devices-ctcu new file mode 100644 index 000000000000..6ff1708fb944 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-ctcu @@ -0,0 +1,8 @@ +What: /sys/bus/coresight/devices/<ctcu-name>/ irq_threshold[0:1] +Date: March 2026 +KernelVersion: 7.1 +Contact: Tingwei Zhang tingwei.zhang@oss.qualcomm.com; Jinlong Mao jinlong.mao@oss.qualcomm.com; Jie Gan jie.gan@oss.qualcomm.com +Description: + (RW) Configure the byte-cntr IRQ register for the specified ETR device + based on its port number. An interrupt is generated when the data size + exceeds the value set in the IRQ register. diff --git a/drivers/hwtracing/coresight/Makefile b/drivers/ hwtracing/ coresight/Makefile index ab16d06783a5..821a1b06b20c 100644 --- a/drivers/hwtracing/coresight/Makefile +++ b/drivers/hwtracing/coresight/Makefile @@ -55,5 +55,5 @@ coresight-cti-y := coresight-cti-core.o coresight- cti-platform.o \ obj-$(CONFIG_ULTRASOC_SMB) += ultrasoc-smb.o obj-$(CONFIG_CORESIGHT_DUMMY) += coresight-dummy.o obj-$(CONFIG_CORESIGHT_CTCU) += coresight-ctcu.o -coresight-ctcu-y := coresight-ctcu-core.o +coresight-ctcu-y := coresight-ctcu-core.o coresight-ctcu-byte-cntr.o obj-$(CONFIG_CORESIGHT_KUNIT_TESTS) += coresight-kunit-tests.o diff --git a/drivers/hwtracing/coresight/coresight-ctcu-byte-cntr.c b/ drivers/hwtracing/coresight/coresight-ctcu-byte-cntr.c new file mode 100644 index 000000000000..0bf738d6c283 --- /dev/null +++ b/drivers/hwtracing/coresight/coresight-ctcu-byte-cntr.c @@ -0,0 +1,351 @@ +// SPDX-License-Identifier: GPL-2.0 +/*
- Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
- */
+#include <linux/coresight.h> +#include <linux/device.h> +#include <linux/fs.h> +#include <linux/interrupt.h> +#include <linux/of_irq.h> +#include <linux/uaccess.h>
+#include "coresight-ctcu.h" +#include "coresight-priv.h" +#include "coresight-tmc.h"
+static irqreturn_t byte_cntr_handler(int irq, void *data) +{ + struct ctcu_byte_cntr *byte_cntr_data = (struct ctcu_byte_cntr *)data;
+ atomic_inc(&byte_cntr_data->irq_cnt); + wake_up(&byte_cntr_data->wq);
+ return IRQ_HANDLED; +}
+static void ctcu_reset_sysfs_buf(struct tmc_drvdata *drvdata)
minor nit: This has nothing to do with the CTCU. For what it is worth, it must be called, tmc_etr_reset_sysf_buf(). But more on this below, and even do we need it, further below.
+{ + u32 sts;
+ CS_UNLOCK(drvdata->base); + tmc_write_rrp(drvdata, drvdata->sysfs_buf->hwaddr); + tmc_write_rwp(drvdata, drvdata->sysfs_buf->hwaddr); + sts = readl_relaxed(drvdata->base + TMC_STS) & ~TMC_STS_FULL; + writel_relaxed(sts, drvdata->base + TMC_STS); + CS_LOCK(drvdata->base);
Could we not keep this function in the tmc-etr.c and invoke from here ?
Sure, will move the function tmc-etr.c
+}
+static void ctcu_cfg_byte_cntr_reg(struct tmc_drvdata *drvdata, u32 val, u32 offset) +{ + struct ctcu_drvdata *ctcu_drvdata; + struct coresight_device *helper;
+ helper = tmc_etr_get_ctcu_device(drvdata); + if (!helper) + return;
+ ctcu_drvdata = dev_get_drvdata(helper->dev.parent); + /* A one value for IRQCTRL register represents 8 bytes */ + ctcu_program_register(ctcu_drvdata, val / 8, offset); +}
+static struct ctcu_byte_cntr *ctcu_get_byte_cntr_data(struct tmc_drvdata *drvdata) +{ + struct ctcu_byte_cntr *byte_cntr_data; + struct ctcu_drvdata *ctcu_drvdata; + struct coresight_device *helper; + int port;
+ helper = tmc_etr_get_ctcu_device(drvdata); + if (!helper) + return NULL;
+ port = coresight_get_in_port(drvdata->csdev, helper); + if (port < 0) + return NULL;
Please validate that the port_num you get is valid for the CTCU ? That applies to all uses of this construct.
Will validate it before using.
+ ctcu_drvdata = dev_get_drvdata(helper->dev.parent); + byte_cntr_data = &ctcu_drvdata->byte_cntr_data[port]; + return byte_cntr_data;
nit: return &ctcu_drvdata->byte_cntr_data[port]; ?
Also, why not make this into a helper, as we seem to use this other places too ?
Didnt get the point here. We may run more than one ETR devices concurrently. So we should get the proper byte_cntr_data according to the port number at runtime.
static struct ctcu_byte_cntr *ctcu_byte_cntr(struct coresight_device *cctcu_dev, struct coresight_device *tmc_etr, ) {
port = coresight_get_in_port().. // Verify the port in this helper and everyone uses this. if (//!validate_port//) return NULL return ... }
Suzuki
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Suzuki K Poulose