1. Patchew
  2. linux
  3. [PATCH v6 0/9] coresight: ctcu: Enable byte-cntr function for TMC ETR
  4. View patch

[PATCH v6 3/9] coresight: tmc: add etr_buf_list to store allocated etr_buf

Jie Gan posted 9 patches 5 months ago
There is a newer version of this series
[PATCH v6 3/9] coresight: tmc: add etr_buf_list to store allocated etr_buf
Posted by Jie Gan 5 months ago 
Add a list to store allocated etr_buf.

The byte-cntr functionality requires two etr_buf to receive trace data.
The active etr_buf collects the trace data from source device, while the
byte-cntr reading function accesses the deactivated etr_buf after is
has been filled and synced, transferring data to the userspace.

Signed-off-by: Jie Gan <jie.gan@oss.qualcomm.com>
---
 drivers/hwtracing/coresight/coresight-tmc-core.c |  1 +
 drivers/hwtracing/coresight/coresight-tmc.h      | 17 +++++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c
index be964656be93..4d249af93097 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-core.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-core.c
@@ -830,6 +830,7 @@ static int __tmc_probe(struct device *dev, struct resource *res)
 		idr_init(&drvdata->idr);
 		mutex_init(&drvdata->idr_mutex);
 		dev_list = &etr_devs;
+		INIT_LIST_HEAD(&drvdata->etr_buf_list);
 		break;
 	case TMC_CONFIG_TYPE_ETF:
 		desc.groups = coresight_etf_groups;
diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h
index 6541a27a018e..292e25d82b62 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.h
+++ b/drivers/hwtracing/coresight/coresight-tmc.h
@@ -208,6 +208,19 @@ struct tmc_resrv_buf {
 	s64		len;
 };
 
+/**
+ * @sysfs_buf:	Allocated sysfs_buf.
+ * @is_free:	Indicates whether the buffer is free to choose.
+ * @pos:	Position of the buffer.
+ * @node:	Node in etr_buf_list.
+ */
+struct etr_buf_node {
+	struct etr_buf		*sysfs_buf;
+	bool			is_free;
+	loff_t			pos;
+	struct list_head	node;
+};
+
 /**
  * struct tmc_drvdata - specifics associated to an TMC component
  * @pclk:	APB clock if present, otherwise NULL
@@ -242,6 +255,8 @@ struct tmc_resrv_buf {
  *		(after crash) by default.
  * @crash_mdata: Reserved memory for storing tmc crash metadata.
  *		 Used by ETR/ETF.
+ * @etr_buf_list: List that is used to manage allocated etr_buf.
+ * @reading_node: Available buffer for byte-cntr reading.
  */
 struct tmc_drvdata {
 	struct clk		*pclk;
@@ -271,6 +286,8 @@ struct tmc_drvdata {
 	struct etr_buf		*perf_buf;
 	struct tmc_resrv_buf	resrv_buf;
 	struct tmc_resrv_buf	crash_mdata;
+	struct list_head        etr_buf_list;
+	struct etr_buf_node     *reading_node;
 };
 
 struct etr_buf_operations {

-- 
2.34.1
Re: [PATCH v6 3/9] coresight: tmc: add etr_buf_list to store allocated etr_buf
Posted by Suzuki K Poulose 2 months, 1 week ago 
On 08/09/2025 03:01, Jie Gan wrote:
> Add a list to store allocated etr_buf.
> 
> The byte-cntr functionality requires two etr_buf to receive trace data.
> The active etr_buf collects the trace data from source device, while the
> byte-cntr reading function accesses the deactivated etr_buf after is
> has been filled and synced, transferring data to the userspace.
> 
> Signed-off-by: Jie Gan <jie.gan@oss.qualcomm.com>

This patch alone doesn't make any sense. Please fold it with a proper 
user (i.e. later patches). I can't make any sense of how this will be
used TBH without the following patches and on its own, it doesn't do
much anyways.

Suzuki


> ---
>   drivers/hwtracing/coresight/coresight-tmc-core.c |  1 +
>   drivers/hwtracing/coresight/coresight-tmc.h      | 17 +++++++++++++++++
>   2 files changed, 18 insertions(+)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c
> index be964656be93..4d249af93097 100644
> --- a/drivers/hwtracing/coresight/coresight-tmc-core.c
> +++ b/drivers/hwtracing/coresight/coresight-tmc-core.c
> @@ -830,6 +830,7 @@ static int __tmc_probe(struct device *dev, struct resource *res)
>   		idr_init(&drvdata->idr);
>   		mutex_init(&drvdata->idr_mutex);
>   		dev_list = &etr_devs;
> +		INIT_LIST_HEAD(&drvdata->etr_buf_list);
>   		break;
>   	case TMC_CONFIG_TYPE_ETF:
>   		desc.groups = coresight_etf_groups;
> diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h
> index 6541a27a018e..292e25d82b62 100644
> --- a/drivers/hwtracing/coresight/coresight-tmc.h
> +++ b/drivers/hwtracing/coresight/coresight-tmc.h
> @@ -208,6 +208,19 @@ struct tmc_resrv_buf {
>   	s64		len;
>   };
>   
> +/**
> + * @sysfs_buf:	Allocated sysfs_buf.
> + * @is_free:	Indicates whether the buffer is free to choose.
> + * @pos:	Position of the buffer.
> + * @node:	Node in etr_buf_list.
> + */
> +struct etr_buf_node {
> +	struct etr_buf		*sysfs_buf;
> +	bool			is_free;
> +	loff_t			pos;
> +	struct list_head	node;
> +};
> +
>   /**
>    * struct tmc_drvdata - specifics associated to an TMC component
>    * @pclk:	APB clock if present, otherwise NULL
> @@ -242,6 +255,8 @@ struct tmc_resrv_buf {
>    *		(after crash) by default.
>    * @crash_mdata: Reserved memory for storing tmc crash metadata.
>    *		 Used by ETR/ETF.
> + * @etr_buf_list: List that is used to manage allocated etr_buf.
> + * @reading_node: Available buffer for byte-cntr reading.
>    */
>   struct tmc_drvdata {
>   	struct clk		*pclk;
> @@ -271,6 +286,8 @@ struct tmc_drvdata {
>   	struct etr_buf		*perf_buf;
>   	struct tmc_resrv_buf	resrv_buf;
>   	struct tmc_resrv_buf	crash_mdata;
> +	struct list_head        etr_buf_list;
> +	struct etr_buf_node     *reading_node;
>   };
>   
>   struct etr_buf_operations {
>
Re: [PATCH v6 3/9] coresight: tmc: add etr_buf_list to store allocated etr_buf
Posted by Mike Leach 2 months, 1 week ago 
On Mon, 8 Sept 2025 at 03:02, Jie Gan <jie.gan@oss.qualcomm.com> wrote:
>
> Add a list to store allocated etr_buf.
>
> The byte-cntr functionality requires two etr_buf to receive trace data.
> The active etr_buf collects the trace data from source device, while the
> byte-cntr reading function accesses the deactivated etr_buf after is
> has been filled and synced, transferring data to the userspace.
>
> Signed-off-by: Jie Gan <jie.gan@oss.qualcomm.com>
> ---
>  drivers/hwtracing/coresight/coresight-tmc-core.c |  1 +
>  drivers/hwtracing/coresight/coresight-tmc.h      | 17 +++++++++++++++++
>  2 files changed, 18 insertions(+)
>
> diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c
> index be964656be93..4d249af93097 100644
> --- a/drivers/hwtracing/coresight/coresight-tmc-core.c
> +++ b/drivers/hwtracing/coresight/coresight-tmc-core.c
> @@ -830,6 +830,7 @@ static int __tmc_probe(struct device *dev, struct resource *res)
>                 idr_init(&drvdata->idr);
>                 mutex_init(&drvdata->idr_mutex);
>                 dev_list = &etr_devs;
> +               INIT_LIST_HEAD(&drvdata->etr_buf_list);
>                 break;
>         case TMC_CONFIG_TYPE_ETF:
>                 desc.groups = coresight_etf_groups;
> diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h
> index 6541a27a018e..292e25d82b62 100644
> --- a/drivers/hwtracing/coresight/coresight-tmc.h
> +++ b/drivers/hwtracing/coresight/coresight-tmc.h
> @@ -208,6 +208,19 @@ struct tmc_resrv_buf {
>         s64             len;
>  };
>
> +/**
> + * @sysfs_buf: Allocated sysfs_buf.
> + * @is_free:   Indicates whether the buffer is free to choose.
> + * @pos:       Position of the buffer.
> + * @node:      Node in etr_buf_list.
> + */
> +struct etr_buf_node {
> +       struct etr_buf          *sysfs_buf;
> +       bool                    is_free;
> +       loff_t                  pos;
> +       struct list_head        node;
> +};
> +
>  /**
>   * struct tmc_drvdata - specifics associated to an TMC component
>   * @pclk:      APB clock if present, otherwise NULL
> @@ -242,6 +255,8 @@ struct tmc_resrv_buf {
>   *             (after crash) by default.
>   * @crash_mdata: Reserved memory for storing tmc crash metadata.
>   *              Used by ETR/ETF.
> + * @etr_buf_list: List that is used to manage allocated etr_buf.
> + * @reading_node: Available buffer for byte-cntr reading.
>   */
>  struct tmc_drvdata {
>         struct clk              *pclk;
> @@ -271,6 +286,8 @@ struct tmc_drvdata {
>         struct etr_buf          *perf_buf;
>         struct tmc_resrv_buf    resrv_buf;
>         struct tmc_resrv_buf    crash_mdata;
> +       struct list_head        etr_buf_list;
> +       struct etr_buf_node     *reading_node;
>  };
>
>  struct etr_buf_operations {
>
> --
> 2.34.1
>

Reviewed-by: Mike Leach <mike.leach@linaro.org>

-- 
Mike Leach
Principal Engineer, ARM Ltd.
Manchester Design Centre. UK

Patchew 2.1-devel-b67e4c2

© 2016 - 2026 Red Hat, Inc.