[PATCH v16 6/7] coresight: ctcu: enable byte-cntr for TMC ETR devices
Jie Gan
jie.gan at oss.qualcomm.com
Mon Apr 6 22:59:06 PDT 2026
On 3/23/2026 5:49 PM, 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.
>
> Byte-cntr workflow:
> start -> ctcu_enable(ctcu_byte_cntr_start) -> tmc_enable_etr_sink ->
> tmc_read_prepare_etr(jump to tmc_read_prepare_byte_cntr) ->
> tmc_etr_get_sysfs_trace(jump to tmc_byte_cntr_get_data) ->
> tmc_disable_etr_sink -> ctcu_disable(ctcu_byte_cntr_stop) ->
> tmc_read_unprepare_etr(jump to tmc_read_unprepare_byte_cntr) -> finish
>
> Signed-off-by: Jie Gan <jie.gan at oss.qualcomm.com>
> ---
> .../ABI/testing/sysfs-bus-coresight-devices-ctcu | 9 +
> drivers/hwtracing/coresight/Makefile | 2 +-
> .../hwtracing/coresight/coresight-ctcu-byte-cntr.c | 286 +++++++++++++++++++++
> drivers/hwtracing/coresight/coresight-ctcu-core.c | 104 +++++++-
> drivers/hwtracing/coresight/coresight-ctcu.h | 79 +++++-
> drivers/hwtracing/coresight/coresight-tmc-core.c | 3 +-
> drivers/hwtracing/coresight/coresight-tmc-etr.c | 104 +++++++-
> drivers/hwtracing/coresight/coresight-tmc.h | 9 +
> 8 files changed, 571 insertions(+), 25 deletions(-)
>
[...]
> +
> +static int tmc_read_prepare_byte_cntr(struct tmc_drvdata *etr_drvdata)
> +{
> + struct coresight_device *ctcu = tmc_etr_get_ctcu_device(etr_drvdata);
> + struct ctcu_byte_cntr *byte_cntr_data;
> + int ret = 0;
> +
> + /* byte-cntr is operating with SYSFS mode being enabled only */
> + if (coresight_get_mode(etr_drvdata->csdev) != CS_MODE_SYSFS)
> + return -EINVAL;
> +
> + byte_cntr_data = ctcu_get_byte_cntr(ctcu, etr_drvdata->csdev);
> + if (!byte_cntr_data || !byte_cntr_data->irq_enabled)
> + return -EINVAL;
> +
> + if (byte_cntr_data->reading)
> + return -EBUSY;
> +
Found a potential race condition here.
I should set the byte_cntr_data->reading as earlier as possible, reset
it if we suffered an issue for creating buffer list to prevent to create
the etr_buf_list twice.
After the correction:
unsigned long flags;
raw_spin_lock_irqsave(&byte_cntr_data->spin_lock, flags);
if (byte_cntr_data->reading)
return -EBUSY;
byte_cntr_data->reading = true;
raw_spin_unlock_irqrestore(&byte_cntr_data->spin_lock, flags);
/* Setup an available etr_buf_list for byte-cntr */
ret = tmc_create_etr_buf_list(etr_drvdata, 2);
if (ret) {
byte_cntr_data->reading = false;
return ret;
}
guard(raw_spinlock_irqsave)(&byte_cntr_data->spin_lock);
...
Thanks,
Jie
> + /* Setup an available etr_buf_list for byte-cntr */
> + ret = tmc_create_etr_buf_list(etr_drvdata, 2);
> + if (ret)
> + return ret;
> +
> + guard(raw_spinlock_irqsave)(&byte_cntr_data->spin_lock);
> + atomic_set(&byte_cntr_data->irq_cnt, 0);
> + /*
> + * Configure the byte-cntr register to enable IRQ. The configured
> + * size is 5% of the buffer_size.
> + */
> + ctcu_cfg_byte_cntr_reg(byte_cntr_data->ctcu_drvdata,
> + etr_drvdata->size / MAX_IRQ_CNT,
> + byte_cntr_data->irq_ctrl_offset);
> + enable_irq_wake(byte_cntr_data->irq);
> + byte_cntr_data->buf_node = NULL;
> + byte_cntr_data->reading = true;
> +
> + return 0;
> +}
> +
> +static int tmc_read_unprepare_byte_cntr(struct tmc_drvdata *etr_drvdata)
> +{
> + struct coresight_device *ctcu = tmc_etr_get_ctcu_device(etr_drvdata);
> + struct ctcu_byte_cntr *byte_cntr_data;
> +
> + byte_cntr_data = ctcu_get_byte_cntr(ctcu, etr_drvdata->csdev);
> + if (!byte_cntr_data || !byte_cntr_data->irq_enabled)
> + return -EINVAL;
> +
> + tmc_clean_etr_buf_list(etr_drvdata);
> + guard(raw_spinlock_irqsave)(&byte_cntr_data->spin_lock);
> + /* Configure the byte-cntr register to disable IRQ */
> + ctcu_cfg_byte_cntr_reg(byte_cntr_data->ctcu_drvdata, 0,
> + byte_cntr_data->irq_ctrl_offset);
> + disable_irq_wake(byte_cntr_data->irq);
> + byte_cntr_data->buf_node = NULL;
> + byte_cntr_data->reading = false;
> +
> + return 0;
> +}
> +
> +const struct tmc_sysfs_ops byte_cntr_sysfs_ops = {
> + .read_prepare = tmc_read_prepare_byte_cntr,
> + .read_unprepare = tmc_read_unprepare_byte_cntr,
> + .get_trace_data = tmc_byte_cntr_get_data,
> +};
> +
> +/* Start the byte-cntr function when the path is enabled. */
> +void ctcu_byte_cntr_start(struct coresight_device *csdev, struct coresight_path *path)
> +{
> + struct coresight_device *sink = coresight_get_sink(path);
> + struct ctcu_byte_cntr *byte_cntr_data;
> +
> + byte_cntr_data = ctcu_get_byte_cntr(csdev, sink);
> + if (!byte_cntr_data)
> + return;
> +
> + /* Don't start byte-cntr function when irq_enabled is not set. */
> + if (!byte_cntr_data->irq_enabled || byte_cntr_data->enable)
> + return;
> +
> + guard(raw_spinlock_irqsave)(&byte_cntr_data->spin_lock);
> + byte_cntr_data->enable = true;
> +}
> +
> +/* Stop the byte-cntr function when the path is disabled. */
> +void ctcu_byte_cntr_stop(struct coresight_device *csdev, struct coresight_path *path)
> +{
> + struct coresight_device *sink = coresight_get_sink(path);
> + struct ctcu_byte_cntr *byte_cntr_data;
> +
> + if (coresight_get_mode(sink) == CS_MODE_SYSFS)
> + return;
> +
> + byte_cntr_data = ctcu_get_byte_cntr(csdev, sink);
> + if (!byte_cntr_data)
> + return;
> +
> + guard(raw_spinlock_irqsave)(&byte_cntr_data->spin_lock);
> + byte_cntr_data->enable = false;
> +}
> +
> +void ctcu_byte_cntr_init(struct device *dev, struct ctcu_drvdata *drvdata, int etr_num)
> +{
> + struct ctcu_byte_cntr *byte_cntr_data;
> + struct device_node *nd = dev->of_node;
> + int irq_num, ret, i;
> +
> + tmc_etr_set_byte_cntr_sysfs_ops(&byte_cntr_sysfs_ops);
> + for (i = 0; i < etr_num; i++) {
> + byte_cntr_data = &drvdata->byte_cntr_data[i];
> + irq_num = of_irq_get(nd, i);
> + if (irq_num < 0) {
> + dev_err(dev, "Failed to get IRQ from DT for port%d\n", i);
> + continue;
> + }
> +
> + ret = devm_request_irq(dev, irq_num, byte_cntr_handler,
> + IRQF_TRIGGER_RISING | IRQF_SHARED,
> + dev_name(dev), byte_cntr_data);
> + if (ret) {
> + dev_err(dev, "Failed to register IRQ for port%d\n", i);
> + continue;
> + }
> +
> + byte_cntr_data->irq = irq_num;
> + byte_cntr_data->ctcu_drvdata = drvdata;
> + init_waitqueue_head(&byte_cntr_data->wq);
> + raw_spin_lock_init(&byte_cntr_data->spin_lock);
> + }
> +}
> diff --git a/drivers/hwtracing/coresight/coresight-ctcu-core.c b/drivers/hwtracing/coresight/coresight-ctcu-core.c
> index e8720026c9e3..56590f22ad79 100644
> --- a/drivers/hwtracing/coresight/coresight-ctcu-core.c
> +++ b/drivers/hwtracing/coresight/coresight-ctcu-core.c
> @@ -1,6 +1,7 @@
> // SPDX-License-Identifier: GPL-2.0-only
> /*
> - * Copyright (c) 2024-2025 Qualcomm Innovation Center, Inc. All rights reserved.
> + * Copyright (c) 2024-2026 Qualcomm Innovation Center, Inc. All rights reserved.
> + * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
> */
>
> #include <linux/clk.h>
> @@ -18,6 +19,7 @@
>
> #include "coresight-ctcu.h"
> #include "coresight-priv.h"
> +#include "coresight-tmc.h"
>
> #define ctcu_writel(drvdata, val, offset) __raw_writel((val), drvdata->base + offset)
> #define ctcu_readl(drvdata, offset) __raw_readl(drvdata->base + offset)
> @@ -43,17 +45,21 @@
>
> #define CTCU_ATID_REG_BIT(traceid) (traceid % 32)
> #define CTCU_ATID_REG_SIZE 0x10
> +#define CTCU_ETR0_IRQCTRL 0x6c
> +#define CTCU_ETR1_IRQCTRL 0x70
> #define CTCU_ETR0_ATID0 0xf8
> #define CTCU_ETR1_ATID0 0x108
>
> static const struct ctcu_etr_config sa8775p_etr_cfgs[] = {
> {
> - .atid_offset = CTCU_ETR0_ATID0,
> - .port_num = 0,
> + .atid_offset = CTCU_ETR0_ATID0,
> + .irq_ctrl_offset = CTCU_ETR0_IRQCTRL,
> + .port_num = 0,
> },
> {
> - .atid_offset = CTCU_ETR1_ATID0,
> - .port_num = 1,
> + .atid_offset = CTCU_ETR1_ATID0,
> + .irq_ctrl_offset = CTCU_ETR1_IRQCTRL,
> + .port_num = 1,
> },
> };
>
> @@ -62,6 +68,85 @@ static const struct ctcu_config sa8775p_cfgs = {
> .num_etr_config = ARRAY_SIZE(sa8775p_etr_cfgs),
> };
>
> +void ctcu_program_register(struct ctcu_drvdata *drvdata, u32 val, u32 offset)
> +{
> + CS_UNLOCK(drvdata->base);
> + ctcu_writel(drvdata, val, offset);
> + CS_LOCK(drvdata->base);
> +}
> +
> +static ssize_t irq_enabled_show(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + struct ctcu_byte_cntr_irq_attribute *irq_attr =
> + container_of(attr, struct ctcu_byte_cntr_irq_attribute, attr);
> + struct ctcu_drvdata *drvdata = dev_get_drvdata(dev->parent);
> + u8 port = irq_attr->port;
> +
> + if (!drvdata->byte_cntr_data[port].irq_ctrl_offset)
> + return -EINVAL;
> +
> + return sysfs_emit(buf, "%u\n",
> + (unsigned int)drvdata->byte_cntr_data[port].irq_enabled);
> +}
> +
> +static ssize_t irq_enabled_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf,
> + size_t size)
> +{
> + struct ctcu_byte_cntr_irq_attribute *irq_attr =
> + container_of(attr, struct ctcu_byte_cntr_irq_attribute, attr);
> + struct ctcu_drvdata *drvdata = dev_get_drvdata(dev->parent);
> + u8 port = irq_attr->port;
> + unsigned long val;
> +
> + if (kstrtoul(buf, 0, &val))
> + return -EINVAL;
> +
> + guard(raw_spinlock_irqsave)(&drvdata->spin_lock);
> + if (drvdata->byte_cntr_data[port].reading)
> + return -EBUSY;
> + else if (drvdata->byte_cntr_data[port].irq_ctrl_offset)
> + drvdata->byte_cntr_data[port].irq_enabled = !!val;
> +
> + return size;
> +}
> +
> +static umode_t irq_enabled_is_visible(struct kobject *kobj,
> + struct attribute *attr, int n)
> +{
> + struct device_attribute *dev_attr =
> + container_of(attr, struct device_attribute, attr);
> + struct ctcu_byte_cntr_irq_attribute *irq_attr =
> + container_of(dev_attr, struct ctcu_byte_cntr_irq_attribute, attr);
> + struct device *dev = kobj_to_dev(kobj);
> + struct ctcu_drvdata *drvdata = dev_get_drvdata(dev->parent);
> + u8 port = irq_attr->port;
> +
> + if (drvdata && drvdata->byte_cntr_data[port].irq_ctrl_offset)
> + return attr->mode;
> +
> + return 0;
> +}
> +
> +static struct attribute *ctcu_attrs[] = {
> + ctcu_byte_cntr_irq_rw(0),
> + ctcu_byte_cntr_irq_rw(1),
> + NULL,
> +};
> +
> +static struct attribute_group ctcu_attr_grp = {
> + .attrs = ctcu_attrs,
> + .is_visible = irq_enabled_is_visible,
> +};
> +
> +static const struct attribute_group *ctcu_attr_grps[] = {
> + &ctcu_attr_grp,
> + NULL,
> +};
> +
> static void ctcu_program_atid_register(struct ctcu_drvdata *drvdata, u32 reg_offset,
> u8 bit, bool enable)
> {
> @@ -140,11 +225,15 @@ static int ctcu_set_etr_traceid(struct coresight_device *csdev, struct coresight
> static int ctcu_enable(struct coresight_device *csdev, enum cs_mode mode,
> struct coresight_path *path)
> {
> + ctcu_byte_cntr_start(csdev, path);
> +
> return ctcu_set_etr_traceid(csdev, path, true);
> }
>
> static int ctcu_disable(struct coresight_device *csdev, struct coresight_path *path)
> {
> + ctcu_byte_cntr_stop(csdev, path);
> +
> return ctcu_set_etr_traceid(csdev, path, false);
> }
>
> @@ -195,7 +284,10 @@ static int ctcu_probe(struct platform_device *pdev)
> for (i = 0; i < cfgs->num_etr_config; i++) {
> etr_cfg = &cfgs->etr_cfgs[i];
> drvdata->atid_offset[i] = etr_cfg->atid_offset;
> + drvdata->byte_cntr_data[i].irq_ctrl_offset =
> + etr_cfg->irq_ctrl_offset;
> }
> + ctcu_byte_cntr_init(dev, drvdata, cfgs->num_etr_config);
> }
> }
>
> @@ -209,6 +301,7 @@ static int ctcu_probe(struct platform_device *pdev)
> desc.dev = dev;
> desc.ops = &ctcu_ops;
> desc.access = CSDEV_ACCESS_IOMEM(base);
> + desc.groups = ctcu_attr_grps;
> raw_spin_lock_init(&drvdata->spin_lock);
>
> drvdata->csdev = coresight_register(&desc);
> @@ -248,6 +341,7 @@ static void ctcu_platform_remove(struct platform_device *pdev)
> if (WARN_ON(!drvdata))
> return;
>
> + tmc_etr_reset_byte_cntr_sysfs_ops();
> ctcu_remove(pdev);
> pm_runtime_disable(&pdev->dev);
> }
> diff --git a/drivers/hwtracing/coresight/coresight-ctcu.h b/drivers/hwtracing/coresight/coresight-ctcu.h
> index e9594c38dd91..a2ae0a0d91d0 100644
> --- a/drivers/hwtracing/coresight/coresight-ctcu.h
> +++ b/drivers/hwtracing/coresight/coresight-ctcu.h
> @@ -1,23 +1,31 @@
> /* SPDX-License-Identifier: GPL-2.0-only */
> /*
> - * Copyright (c) 2024-2025 Qualcomm Innovation Center, Inc. All rights reserved.
> + * Copyright (c) 2024-2026 Qualcomm Innovation Center, Inc. All rights reserved.
> + * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
> */
>
> #ifndef _CORESIGHT_CTCU_H
> #define _CORESIGHT_CTCU_H
> +
> +#include <linux/time.h>
> #include "coresight-trace-id.h"
>
> /* Maximum number of supported ETR devices for a single CTCU. */
> #define ETR_MAX_NUM 2
>
> +#define BYTE_CNTR_TIMEOUT (3 * HZ)
> +#define MAX_IRQ_CNT 20
> +
> /**
> * struct ctcu_etr_config
> * @atid_offset: offset to the ATID0 Register.
> - * @port_num: in-port number of CTCU device that connected to ETR.
> + * @port_num: in-port number of the CTCU device that connected to ETR.
> + * @irq_ctrl_offset: offset to the BYTECNTRVAL register.
> */
> struct ctcu_etr_config {
> const u32 atid_offset;
> const u32 port_num;
> + const u32 irq_ctrl_offset;
> };
>
> struct ctcu_config {
> @@ -25,15 +33,68 @@ struct ctcu_config {
> int num_etr_config;
> };
>
> -struct ctcu_drvdata {
> - void __iomem *base;
> - struct clk *apb_clk;
> - struct device *dev;
> - struct coresight_device *csdev;
> +/**
> + * struct ctcu_byte_cntr
> + * @enable: indicates that byte_cntr function is enabled or not.
> + * @irq_enabled: indicates that the interruption is enabled.
> + * @reading: indicates that byte_cntr is reading.
> + * @irq: allocated number of the IRQ.
> + * @irq_cnt: IRQ count number of the triggered interruptions.
> + * @wq: waitqueue for reading data from ETR buffer.
> + * @spin_lock: spinlock of the byte_cntr_data.
> + * @irq_ctrl_offset: offset to the BYTECNTVAL Register.
> + * @ctcu_drvdata: drvdata of the CTCU device.
> + * @buf_node: etr_buf_node for reading.
> + */
> +struct ctcu_byte_cntr {
> + bool enable;
> + bool irq_enabled;
> + bool reading;
> + int irq;
> + atomic_t irq_cnt;
> + wait_queue_head_t wq;
> raw_spinlock_t spin_lock;
> - u32 atid_offset[ETR_MAX_NUM];
> + u32 irq_ctrl_offset;
> + struct ctcu_drvdata *ctcu_drvdata;
> + struct etr_buf_node *buf_node;
> +};
> +
> +struct ctcu_drvdata {
> + void __iomem *base;
> + struct clk *apb_clk;
> + struct device *dev;
> + struct coresight_device *csdev;
> + struct ctcu_byte_cntr byte_cntr_data[ETR_MAX_NUM];
> + raw_spinlock_t spin_lock;
> + u32 atid_offset[ETR_MAX_NUM];
> /* refcnt for each traceid of each sink */
> - u8 traceid_refcnt[ETR_MAX_NUM][CORESIGHT_TRACE_ID_RES_TOP];
> + u8 traceid_refcnt[ETR_MAX_NUM][CORESIGHT_TRACE_ID_RES_TOP];
> };
>
> +/**
> + * struct ctcu_byte_cntr_irq_attribute
> + * @attr: The device attribute.
> + * @port: port number.
> + */
> +struct ctcu_byte_cntr_irq_attribute {
> + struct device_attribute attr;
> + u8 port;
> +};
> +
> +#define ctcu_byte_cntr_irq_rw(port) \
> + (&((struct ctcu_byte_cntr_irq_attribute[]) { \
> + { \
> + __ATTR(irq_enabled##port, 0644, irq_enabled_show, \
> + irq_enabled_store), \
> + port, \
> + } \
> + })[0].attr.attr)
> +
> +void ctcu_program_register(struct ctcu_drvdata *drvdata, u32 val, u32 offset);
> +
> +/* Byte-cntr functions */
> +void ctcu_byte_cntr_start(struct coresight_device *csdev, struct coresight_path *path);
> +void ctcu_byte_cntr_stop(struct coresight_device *csdev, struct coresight_path *path);
> +void ctcu_byte_cntr_init(struct device *dev, struct ctcu_drvdata *drvdata, int port_num);
> +
> #endif
> diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c
> index 110eedde077f..9f4fd86e8c32 100644
> --- a/drivers/hwtracing/coresight/coresight-tmc-core.c
> +++ b/drivers/hwtracing/coresight/coresight-tmc-core.c
> @@ -293,7 +293,8 @@ static ssize_t tmc_read(struct file *file, char __user *data, size_t len,
> return -EFAULT;
> }
>
> - *ppos += actual;
> + if (!tmc_etr_update_buf_node_pos(drvdata, actual))
> + *ppos += actual;
> dev_dbg(&drvdata->csdev->dev, "%zu bytes copied\n", actual);
>
> return actual;
> diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
> index d4a99c77dd90..3253964d1ce7 100644
> --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
> +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
> @@ -1168,6 +1168,8 @@ static int tmc_etr_enable_hw(struct tmc_drvdata *drvdata,
> return rc;
> }
>
> +static const struct tmc_sysfs_ops *byte_cntr_sysfs_ops;
> +
> /*
> * Return the available trace data in the buffer (starts at etr_buf->offset,
> * limited by etr_buf->len) from @pos, with a maximum limit of @len,
> @@ -1178,23 +1180,39 @@ static int tmc_etr_enable_hw(struct tmc_drvdata *drvdata,
> * We are protected here by drvdata->reading != 0, which ensures the
> * sysfs_buf stays alive.
> */
> -ssize_t tmc_etr_get_sysfs_trace(struct tmc_drvdata *drvdata,
> - loff_t pos, size_t len, char **bufpp)
> +ssize_t tmc_etr_read_sysfs_buf(struct etr_buf *sysfs_buf, loff_t pos,
> + size_t len, char **bufpp)
> {
> s64 offset;
> ssize_t actual = len;
> - struct etr_buf *etr_buf = drvdata->sysfs_buf;
>
> - if (pos + actual > etr_buf->len)
> - actual = etr_buf->len - pos;
> + if (pos + actual > sysfs_buf->len)
> + actual = sysfs_buf->len - pos;
> if (actual <= 0)
> return actual;
>
> /* Compute the offset from which we read the data */
> - offset = etr_buf->offset + pos;
> - if (offset >= etr_buf->size)
> - offset -= etr_buf->size;
> - return tmc_etr_buf_get_data(etr_buf, offset, actual, bufpp);
> + offset = sysfs_buf->offset + pos;
> + if (offset >= sysfs_buf->size)
> + offset -= sysfs_buf->size;
> + return tmc_etr_buf_get_data(sysfs_buf, offset, actual, bufpp);
> +}
> +EXPORT_SYMBOL_GPL(tmc_etr_read_sysfs_buf);
> +
> +ssize_t tmc_etr_get_sysfs_trace(struct tmc_drvdata *drvdata,
> + loff_t pos, size_t len, char **bufpp)
> +{
> + ssize_t ret;
> +
> + if (byte_cntr_sysfs_ops) {
> + ret = byte_cntr_sysfs_ops->get_trace_data(drvdata, pos,
> + len, bufpp);
> + /* Return the filled buffer */
> + if (ret > 0 || ret == -ENOMEM)
> + return ret;
> + }
> +
> + return tmc_etr_read_sysfs_buf(drvdata->sysfs_buf, pos, len, bufpp);
> }
>
> static struct etr_buf *
> @@ -1248,6 +1266,33 @@ static void __tmc_etr_disable_hw(struct tmc_drvdata *drvdata)
>
> }
>
> +static void tmc_etr_reset_sysfs_buf(struct tmc_drvdata *drvdata)
> +{
> + 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);
> +}
> +
> +/**
> + * tmc_etr_enable_disable_hw - enable/disable the ETR hw.
> + * @drvdata: drvdata of the TMC device.
> + * @enable: indicates enable/disable.
> + */
> +void tmc_etr_enable_disable_hw(struct tmc_drvdata *drvdata, bool enable)
> +{
> + if (enable) {
> + tmc_etr_reset_sysfs_buf(drvdata);
> + __tmc_etr_enable_hw(drvdata);
> + } else
> + __tmc_etr_disable_hw(drvdata);
> +}
> +EXPORT_SYMBOL_GPL(tmc_etr_enable_disable_hw);
> +
> void tmc_etr_disable_hw(struct tmc_drvdata *drvdata)
> {
> __tmc_etr_disable_hw(drvdata);
> @@ -2040,6 +2085,35 @@ int tmc_create_etr_buf_list(struct tmc_drvdata *drvdata, int num_nodes)
> }
> EXPORT_SYMBOL_GPL(tmc_create_etr_buf_list);
>
> +void tmc_etr_set_byte_cntr_sysfs_ops(const struct tmc_sysfs_ops *sysfs_ops)
> +{
> + byte_cntr_sysfs_ops = sysfs_ops;
> +}
> +EXPORT_SYMBOL_GPL(tmc_etr_set_byte_cntr_sysfs_ops);
> +
> +void tmc_etr_reset_byte_cntr_sysfs_ops(void)
> +{
> + byte_cntr_sysfs_ops = NULL;
> +}
> +EXPORT_SYMBOL_GPL(tmc_etr_reset_byte_cntr_sysfs_ops);
> +
> +bool tmc_etr_update_buf_node_pos(struct tmc_drvdata *drvdata, ssize_t size)
> +{
> + struct etr_buf_node *nd, *next;
> +
> + if (drvdata->config_type != TMC_CONFIG_TYPE_ETR)
> + return false;
> +
> + list_for_each_entry_safe(nd, next, &drvdata->etr_buf_list, link) {
> + if (nd && nd->reading) {
> + nd->pos += size;
> + return true;
> + }
> + }
> +
> + return false;
> +}
> +
> int tmc_read_prepare_etr(struct tmc_drvdata *drvdata)
> {
> int ret = 0;
> @@ -2049,6 +2123,14 @@ int tmc_read_prepare_etr(struct tmc_drvdata *drvdata)
> if (WARN_ON_ONCE(drvdata->config_type != TMC_CONFIG_TYPE_ETR))
> return -EINVAL;
>
> + if (byte_cntr_sysfs_ops) {
> + ret = byte_cntr_sysfs_ops->read_prepare(drvdata);
> + if (!ret || ret == -EBUSY)
> + return ret;
> +
> + ret = 0;
> + }
> +
> raw_spin_lock_irqsave(&drvdata->spinlock, flags);
> if (drvdata->reading) {
> ret = -EBUSY;
> @@ -2085,6 +2167,10 @@ int tmc_read_unprepare_etr(struct tmc_drvdata *drvdata)
> if (WARN_ON_ONCE(drvdata->config_type != TMC_CONFIG_TYPE_ETR))
> return -EINVAL;
>
> + if (byte_cntr_sysfs_ops)
> + if (!byte_cntr_sysfs_ops->read_unprepare(drvdata))
> + return 0;
> +
> raw_spin_lock_irqsave(&drvdata->spinlock, flags);
>
> /* RE-enable the TMC if need be */
> diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h
> index fbb015079872..a15e2f93f16a 100644
> --- a/drivers/hwtracing/coresight/coresight-tmc.h
> +++ b/drivers/hwtracing/coresight/coresight-tmc.h
> @@ -211,12 +211,15 @@ struct tmc_resrv_buf {
> /**
> * @sysfs_buf: Allocated sysfs_buf.
> * @is_free: Indicates whether the buffer is free to choose.
> + * @reading: Indicates byte_cntr is reading the buffer attached to
> + * the node.
> * @pos: Offset to the start of the buffer.
> * @link: list_head of the node.
> */
> struct etr_buf_node {
> struct etr_buf *sysfs_buf;
> bool is_free;
> + bool reading;
> loff_t pos;
> struct list_head link;
> };
> @@ -480,5 +483,11 @@ struct etr_buf *tmc_etr_get_buffer(struct coresight_device *csdev,
> extern const struct attribute_group coresight_etr_group;
> void tmc_clean_etr_buf_list(struct tmc_drvdata *drvdata);
> int tmc_create_etr_buf_list(struct tmc_drvdata *drvdata, int num_nodes);
> +void tmc_etr_set_byte_cntr_sysfs_ops(const struct tmc_sysfs_ops *sysfs_ops);
> +void tmc_etr_reset_byte_cntr_sysfs_ops(void);
> +void tmc_etr_enable_disable_hw(struct tmc_drvdata *drvdata, bool enable);
> +bool tmc_etr_update_buf_node_pos(struct tmc_drvdata *drvdata, ssize_t size);
> +ssize_t tmc_etr_read_sysfs_buf(struct etr_buf *sysfs_buf, loff_t pos,
> + size_t len, char **bufpp);
>
> #endif
>
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