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Message-Id: <20250624060438.7469-10-jie.gan@oss.qualcomm.com>
Date: Tue, 24 Jun 2025 14:04:37 +0800
From: Jie Gan <jie.gan@....qualcomm.com>
To: Suzuki K Poulose <suzuki.poulose@....com>,
Mike Leach <mike.leach@...aro.org>,
James Clark <james.clark@...aro.org>, Rob Herring <robh@...nel.org>,
Krzysztof Kozlowski <krzk+dt@...nel.org>,
Conor Dooley <conor+dt@...nel.org>,
Bjorn Andersson <andersson@...nel.org>,
Konrad Dybcio <konradybcio@...nel.org>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Cc: Tingwei Zhang <quic_tingweiz@...cinc.com>, coresight@...ts.linaro.org,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
jie.gan@....qualcomm.com
Subject: [PATCH v3 09/10] coresight: tmc: add read function for byte-cntr
The byte-cntr read function always reads trace data from the deactivated
and filled buffer which is already synced. The read function will fail
when the ETR cannot find a available buffer to receive trace data.
The read function terminates when the path is disabled or interrupted by a
signal.
Signed-off-by: Jie Gan <jie.gan@....qualcomm.com>
---
.../hwtracing/coresight/coresight-tmc-core.c | 31 ++++++-
.../hwtracing/coresight/coresight-tmc-etr.c | 90 +++++++++++++++++++
drivers/hwtracing/coresight/coresight-tmc.h | 4 +-
3 files changed, 120 insertions(+), 5 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c
index 40605310240d..7b09cf060666 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-core.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-core.c
@@ -317,14 +317,18 @@ static int tmc_open(struct inode *inode, struct file *file)
return 0;
}
-static ssize_t tmc_get_sysfs_trace(struct tmc_drvdata *drvdata, loff_t pos, size_t len,
- char **bufpp)
+static ssize_t tmc_get_sysfs_trace(struct tmc_drvdata *drvdata,
+ struct ctcu_byte_cntr *byte_cntr_data,
+ loff_t pos, size_t len, char **bufpp)
{
switch (drvdata->config_type) {
case TMC_CONFIG_TYPE_ETB:
case TMC_CONFIG_TYPE_ETF:
return tmc_etb_get_sysfs_trace(drvdata, pos, len, bufpp);
case TMC_CONFIG_TYPE_ETR:
+ if (byte_cntr_data && byte_cntr_data->thresh_val)
+ return tmc_byte_cntr_get_data(drvdata, byte_cntr_data, len, bufpp);
+
return tmc_etr_get_sysfs_trace(drvdata, pos, len, bufpp);
}
@@ -338,7 +342,21 @@ static ssize_t tmc_read(struct file *file, char __user *data, size_t len,
ssize_t actual;
struct tmc_drvdata *drvdata = container_of(file->private_data,
struct tmc_drvdata, miscdev);
- actual = tmc_get_sysfs_trace(drvdata, *ppos, len, &bufp);
+ struct coresight_device *helper = coresight_get_helper(drvdata->csdev,
+ CORESIGHT_DEV_SUBTYPE_HELPER_CTCU);
+ struct ctcu_byte_cntr *byte_cntr_data = NULL;
+ struct ctcu_drvdata *ctcu_drvdata = NULL;
+ int port;
+
+ if (helper) {
+ port = coresight_get_port_helper(drvdata->csdev, helper);
+ if (port >= 0) {
+ ctcu_drvdata = dev_get_drvdata(helper->dev.parent);
+ byte_cntr_data = &ctcu_drvdata->byte_cntr_data[port];
+ }
+ }
+
+ actual = tmc_get_sysfs_trace(drvdata, byte_cntr_data, *ppos, len, &bufp);
if (actual <= 0)
return 0;
@@ -348,7 +366,12 @@ static ssize_t tmc_read(struct file *file, char __user *data, size_t len,
return -EFAULT;
}
- *ppos += actual;
+ if (byte_cntr_data && byte_cntr_data->thresh_val) {
+ byte_cntr_data->total_size += actual;
+ drvdata->reading_node->pos += actual;
+ } else
+ *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 3e3e1b5e78ca..8f53ecb12ad3 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -1163,6 +1163,10 @@ ssize_t tmc_etr_get_sysfs_trace(struct tmc_drvdata *drvdata,
ssize_t actual = len;
struct etr_buf *etr_buf = drvdata->sysfs_buf;
+ /* Reading the buf defind in buf_node if it exists*/
+ if (drvdata->reading_node)
+ etr_buf = drvdata->reading_node->sysfs_buf;
+
if (pos + actual > etr_buf->len)
actual = etr_buf->len - pos;
if (actual <= 0)
@@ -1339,6 +1343,92 @@ static bool tmc_byte_cntr_switch_buffer(struct tmc_drvdata *drvdata,
return found_free_buf;
}
+/*
+ * tmc_byte_cntr_get_data() - reads data from the deactived and filled buffer.
+ * The byte-cntr reading work reads data from the deactived and filled buffer.
+ * The read operation waits for a buffer to become available, either filled or
+ * upon timeout, and then reads trace data from the synced buffer.
+ */
+ssize_t tmc_byte_cntr_get_data(struct tmc_drvdata *drvdata,
+ struct ctcu_byte_cntr *byte_cntr_data,
+ size_t len, char **bufpp)
+{
+ size_t thresh_val = byte_cntr_data->thresh_val;
+ atomic_t *irq_cnt = &byte_cntr_data->irq_cnt;
+ struct etr_buf *sysfs_buf = drvdata->sysfs_buf;
+ struct device *dev = &drvdata->csdev->dev;
+ struct etr_buf_node *nd, *next;
+ ssize_t size = sysfs_buf->size;
+ ssize_t actual;
+ loff_t pos;
+ int ret;
+
+wait_buffer:
+ if (!byte_cntr_data->reading_buf) {
+ ret = wait_event_interruptible_timeout(byte_cntr_data->wq,
+ ((atomic_read(irq_cnt) + 1) * thresh_val >= size) ||
+ !byte_cntr_data->enable,
+ BYTE_CNTR_TIMEOUT);
+ if (ret < 0)
+ return ret;
+ /*
+ * The current etr_buf is almost full or timeout is triggered,
+ * so switch the buffer and mark the switched buffer as reading.
+ */
+ if (byte_cntr_data->enable) {
+ if (!tmc_byte_cntr_switch_buffer(drvdata, byte_cntr_data)) {
+ dev_err(dev, "Switch buffer failed for byte-cntr\n");
+ return -EINVAL;
+ }
+
+ byte_cntr_data->reading_buf = true;
+ } else {
+ if (!drvdata->reading_node) {
+ list_for_each_entry_safe(nd, next, &drvdata->etr_buf_list, node) {
+ if (nd->sysfs_buf == sysfs_buf) {
+ nd->pos = 0;
+ drvdata->reading_node = nd;
+ break;
+ }
+ }
+ }
+
+ pos = drvdata->reading_node->pos;
+ actual = tmc_etr_get_sysfs_trace(drvdata, pos, len, bufpp);
+ if (actual > 0)
+ return actual;
+
+ drvdata->reading_node = NULL;
+
+ /* Exit byte-cntr reading */
+ return -EINVAL;
+ }
+ }
+
+ /* Check the status of current etr_buf*/
+ if ((atomic_read(irq_cnt) + 1) * thresh_val >= size)
+ /*
+ * Unlikely to find a free buffer to switch, so just disable
+ * the ETR for a while.
+ */
+ if (!tmc_byte_cntr_switch_buffer(drvdata, byte_cntr_data))
+ dev_info(dev, "No available buffer to store data, disable ETR\n");
+
+ pos = drvdata->reading_node->pos;
+ actual = tmc_etr_get_sysfs_trace(drvdata, pos, len, bufpp);
+ if (actual == 0) {
+ /* Reading work for marked buffer has finished, reset flags */
+ drvdata->reading_node->reading = false;
+ byte_cntr_data->reading_buf = false;
+ drvdata->reading_node = NULL;
+
+ /* Nothing in the buffer, wait for next buffer to be filled */
+ goto wait_buffer;
+ }
+
+ return actual;
+}
+
static int tmc_enable_etr_sink_sysfs(struct coresight_device *csdev)
{
int ret = 0;
diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h
index f95df0a34ad6..4136ec5ecaf7 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.h
+++ b/drivers/hwtracing/coresight/coresight-tmc.h
@@ -364,7 +364,9 @@ int tmc_read_prepare_byte_cntr(struct tmc_drvdata *drvdata,
struct ctcu_byte_cntr *byte_cntr_data);
int tmc_read_unprepare_byte_cntr(struct tmc_drvdata *drvdata,
struct ctcu_byte_cntr *byte_cntr_data);
-
+ssize_t tmc_byte_cntr_get_data(struct tmc_drvdata *drvdata,
+ struct ctcu_byte_cntr *byte_cntr_data,
+ size_t len, char **bufpp);
#define TMC_REG_PAIR(name, lo_off, hi_off) \
static inline u64 \
--
2.34.1
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