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Subject[PATCH 01/13] coresight: tmc-etr: Refactor for handling errors
Date
Refactor the tmc-etr enable operation to make it easier to
handle errors in enabling the hardware. We need to make
sure that the buffer is compatible with the ETR. This
patch re-arranges to make the error handling easier, by
deferring the hardware enablement until all the errors
are checked. This also avoids turning the CATU on/off
during a sysfs read session.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
drivers/hwtracing/coresight/coresight-tmc-etr.c | 67 ++++++++++++++++---------
1 file changed, 43 insertions(+), 24 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index 56fea4f..c426935 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -918,21 +918,10 @@ static void tmc_sync_etr_buf(struct tmc_drvdata *drvdata)
tmc_etr_buf_insert_barrier_packet(etr_buf, etr_buf->offset);
}

-static void tmc_etr_enable_hw(struct tmc_drvdata *drvdata,
- struct etr_buf *etr_buf)
+static void __tmc_etr_enable_hw(struct tmc_drvdata *drvdata)
{
u32 axictl, sts;
-
- /* Callers should provide an appropriate buffer for use */
- if (WARN_ON(!etr_buf || drvdata->etr_buf))
- return;
- drvdata->etr_buf = etr_buf;
-
- /*
- * If this ETR is connected to a CATU, enable it before we turn
- * this on
- */
- tmc_etr_enable_catu(drvdata);
+ struct etr_buf *etr_buf = drvdata->etr_buf;

CS_UNLOCK(drvdata->base);

@@ -952,11 +941,8 @@ static void tmc_etr_enable_hw(struct tmc_drvdata *drvdata,
axictl |= TMC_AXICTL_ARCACHE_OS;
}

- if (etr_buf->mode == ETR_MODE_ETR_SG) {
- if (WARN_ON(!tmc_etr_has_cap(drvdata, TMC_ETR_SG)))
- return;
+ if (etr_buf->mode == ETR_MODE_ETR_SG)
axictl |= TMC_AXICTL_SCT_GAT_MODE;
- }

writel_relaxed(axictl, drvdata->base + TMC_AXICTL);
tmc_write_dba(drvdata, etr_buf->hwaddr);
@@ -982,6 +968,32 @@ static void tmc_etr_enable_hw(struct tmc_drvdata *drvdata,
CS_LOCK(drvdata->base);
}

+static int tmc_etr_enable_hw(struct tmc_drvdata *drvdata,
+ struct etr_buf *etr_buf)
+{
+ /* Callers should provide an appropriate buffer for use */
+ if (WARN_ON(!etr_buf))
+ return -EINVAL;
+
+ if ((etr_buf->mode == ETR_MODE_ETR_SG) &&
+ WARN_ON(!tmc_etr_has_cap(drvdata, TMC_ETR_SG)))
+ return -EINVAL;
+
+ if (WARN_ON(drvdata->etr_buf))
+ return -EBUSY;
+
+ /* Set the buffer for the session */
+ drvdata->etr_buf = etr_buf;
+ /*
+ * If this ETR is connected to a CATU, enable it before we turn
+ * this on.
+ */
+ tmc_etr_enable_catu(drvdata);
+
+ __tmc_etr_enable_hw(drvdata);
+ return 0;
+}
+
/*
* 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,
@@ -1037,7 +1049,7 @@ static void tmc_etr_sync_sysfs_buf(struct tmc_drvdata *drvdata)
}
}

-static void tmc_etr_disable_hw(struct tmc_drvdata *drvdata)
+static void __tmc_etr_disable_hw(struct tmc_drvdata *drvdata)
{
CS_UNLOCK(drvdata->base);

@@ -1053,6 +1065,11 @@ static void tmc_etr_disable_hw(struct tmc_drvdata *drvdata)

CS_LOCK(drvdata->base);

+}
+
+static void tmc_etr_disable_hw(struct tmc_drvdata *drvdata)
+{
+ __tmc_etr_disable_hw(drvdata);
/* Disable CATU device if this ETR is connected to one */
tmc_etr_disable_catu(drvdata);
/* Reset the ETR buf used by hardware */
@@ -1111,8 +1128,9 @@ static int tmc_enable_etr_sink_sysfs(struct coresight_device *csdev)
drvdata->sysfs_buf = new_buf;
}

- drvdata->mode = CS_MODE_SYSFS;
- tmc_etr_enable_hw(drvdata, drvdata->sysfs_buf);
+ ret = tmc_etr_enable_hw(drvdata, drvdata->sysfs_buf);
+ if (!ret)
+ drvdata->mode = CS_MODE_SYSFS;
out:
spin_unlock_irqrestore(&drvdata->spinlock, flags);

@@ -1342,8 +1360,9 @@ static int tmc_enable_etr_sink_perf(struct coresight_device *csdev, void *data)

etr_perf->head = PERF_IDX2OFF(handle->head, etr_perf);
drvdata->perf_data = etr_perf;
- drvdata->mode = CS_MODE_PERF;
- tmc_etr_enable_hw(drvdata, etr_perf->etr_buf);
+ rc = tmc_etr_enable_hw(drvdata, etr_perf->etr_buf);
+ if (!rc)
+ drvdata->mode = CS_MODE_PERF;

unlock_out:
spin_unlock_irqrestore(&drvdata->spinlock, flags);
@@ -1425,7 +1444,7 @@ int tmc_read_prepare_etr(struct tmc_drvdata *drvdata)

/* Disable the TMC if we are trying to read from a running session. */
if (drvdata->mode == CS_MODE_SYSFS)
- tmc_etr_disable_hw(drvdata);
+ __tmc_etr_disable_hw(drvdata);

drvdata->reading = true;
out:
@@ -1452,7 +1471,7 @@ int tmc_read_unprepare_etr(struct tmc_drvdata *drvdata)
* buffer. Since the tracer is still enabled drvdata::buf can't
* be NULL.
*/
- tmc_etr_enable_hw(drvdata, drvdata->sysfs_buf);
+ __tmc_etr_enable_hw(drvdata);
} else {
/*
* The ETR is not tracing and the buffer was just read.
--
2.7.4
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