Re: [PATCH v4 03/10] coresight: tmc: add etr_buf_list to store allocated etr_buf

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 <redacted>
---
 .../hwtracing/coresight/coresight-tmc-core.c  |  1 +
 drivers/hwtracing/coresight/coresight-tmc.h   | 19 +++++++++++++++++++
 2 files changed, 20 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..52ee5f8efe8c 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.h
+++ b/drivers/hwtracing/coresight/coresight-tmc.h

@@ -208,6 +208,21 @@ struct tmc_resrv_buf {
        s64             len;
 };

+/**
+ * @sysfs_buf: Allocated sysfs_buf.
+ * @is_free:   Indicates whether the buffer is free to choose.
+ * @reading:   Indicates whether the buffer is reading.
+ * @pos:       Position of the buffer.
+ * @node:      Node in etr_buf_list.
+ */
+struct etr_buf_node {
+       struct etr_buf          *sysfs_buf;
+       bool                    is_free;
+       bool                    reading;
+       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 +257,8 @@ 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 +288,8 @@ 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;