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Date: Tue, 22 Mar 2016 14:23:18 -0600
From: Mathieu Poirier <mathieu.poirier@...aro.org>
To: linux-arm-kernel@...ts.infradead.org
Cc: linux-kernel@...r.kernel.org
Subject: [PATCH 10/14] coresight: tmc: make sysFS and Perf mode mutually exclusive
The sysFS and Perf access methods can't be allowed to interfere
with one another. As such introducing guards to access
functions that prevents moving forward if a TMC is already
being used.
Signed-off-by: Mathieu Poirier <mathieu.poirier@...aro.org>
---
drivers/hwtracing/coresight/coresight-tmc-etf.c | 76 +++++++++++++++++++++---
drivers/hwtracing/coresight/coresight-tmc-etr.c | 77 ++++++++++++++++++++++---
2 files changed, 139 insertions(+), 14 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c
index a88c76d7f473..c533b4494969 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etf.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c
@@ -106,7 +106,7 @@ static void tmc_etf_disable_hw(struct tmc_drvdata *drvdata)
CS_LOCK(drvdata->base);
}
-static int tmc_enable_etf_sink(struct coresight_device *csdev, u32 mode)
+static int tmc_enable_etf_sink_sysfs(struct coresight_device *csdev, u32 mode)
{
u32 val;
bool allocated = false;
@@ -127,6 +127,12 @@ static int tmc_enable_etf_sink(struct coresight_device *csdev, u32 mode)
}
val = local_cmpxchg(&drvdata->mode, CS_MODE_DISABLED, mode);
+ /* No need to continue if already operated from Perf */
+ if (val == CS_MODE_PERF) {
+ spin_unlock_irqrestore(&drvdata->spinlock, flags);
+ kfree(buf);
+ return -EBUSY;
+ }
/*
* In sysFS mode we can have multiple writers per sink. Since this
* sink is already enabled no memory is needed and the HW need not be
@@ -162,7 +168,7 @@ out:
return 0;
}
-static void tmc_disable_etf_sink(struct coresight_device *csdev)
+static int tmc_enable_etf_sink_perf(struct coresight_device *csdev, u32 mode)
{
u32 val;
unsigned long flags;
@@ -171,16 +177,66 @@ static void tmc_disable_etf_sink(struct coresight_device *csdev)
spin_lock_irqsave(&drvdata->spinlock, flags);
if (drvdata->reading) {
spin_unlock_irqrestore(&drvdata->spinlock, flags);
+ return -EBUSY;
+ }
+
+ val = local_cmpxchg(&drvdata->mode, CS_MODE_DISABLED, mode);
+ /*
+ * In Perf mode there can be only one writer per sink. There
+ * is also no need to continue if the ETB/ETR is already operated
+ * from sysFS.
+ */
+ if (val != CS_MODE_DISABLED) {
+ spin_unlock_irqrestore(&drvdata->spinlock, flags);
+ return -EBUSY;
+ }
+
+ tmc_etb_enable_hw(drvdata);
+ spin_unlock_irqrestore(&drvdata->spinlock, flags);
+
+ return 0;
+}
+
+static int tmc_enable_etf_sink(struct coresight_device *csdev, u32 mode)
+{
+ switch (mode) {
+ case CS_MODE_SYSFS:
+ return tmc_enable_etf_sink_sysfs(csdev, mode);
+ case CS_MODE_PERF:
+ return tmc_enable_etf_sink_perf(csdev, mode);
+ }
+
+ /* We shouldn't be here */
+ return -EINVAL;
+}
+
+static void tmc_disable_etf_sink(struct coresight_device *csdev)
+{
+ u32 mode;
+ unsigned long flags;
+ struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+
+ spin_lock_irqsave(&drvdata->spinlock, flags);
+ if (drvdata->reading) {
+ spin_unlock_irqrestore(&drvdata->spinlock, flags);
return;
}
- val = local_cmpxchg(&drvdata->mode, CS_MODE_SYSFS, CS_MODE_DISABLED);
- /* Nothing to do, the TMC was already disabled */
- if (val == CS_MODE_DISABLED)
+ mode = local_xchg(&drvdata->mode, CS_MODE_DISABLED);
+ /* Nothing to do, the ETB/ETF was already disabled */
+ if (mode == CS_MODE_DISABLED)
goto out;
+ /* The engine has to be stopped in both sysFS and Perf mode */
tmc_etb_disable_hw(drvdata);
- tmc_etb_dump_hw(drvdata);
+
+ /*
+ * If we operated from sysFS, dump the trace data for retrieval
+ * via /dev/. From Perf trace data is handled via the Perf ring
+ * buffer.
+ */
+ if (mode == CS_MODE_SYSFS)
+ tmc_etb_dump_hw(drvdata);
out:
spin_unlock_irqrestore(&drvdata->spinlock, flags);
@@ -253,7 +309,13 @@ int tmc_read_prepare_etf(struct tmc_drvdata *drvdata)
spin_lock_irqsave(&drvdata->spinlock, flags);
- /* The TMC isn't enabled, so there is no need to disable it */
+ /* Don't interfere if operated from Perf */
+ if (local_read(&drvdata->mode) == CS_MODE_PERF) {
+ spin_unlock_irqrestore(&drvdata->spinlock, flags);
+ return -EBUSY;
+ }
+
+ /* The ETB/ETF isn't enabled, so there is no need to disable it */
if (local_read(&drvdata->mode) == CS_MODE_DISABLED) {
/*
* The ETB/ETF is disabled already. If drvdata::buf is NULL
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index 540d0b96a958..50a2e0a83714 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -82,7 +82,7 @@ static void tmc_etr_disable_hw(struct tmc_drvdata *drvdata)
CS_LOCK(drvdata->base);
}
-static int tmc_enable_etr_sink(struct coresight_device *csdev, u32 mode)
+static int tmc_enable_etr_sink_sysfs(struct coresight_device *csdev, u32 mode)
{
u32 val;
bool allocated = false;
@@ -109,6 +109,13 @@ static int tmc_enable_etr_sink(struct coresight_device *csdev, u32 mode)
}
val = local_cmpxchg(&drvdata->mode, CS_MODE_DISABLED, mode);
+ /* No need to continue if already operated from Perf */
+ if (val == CS_MODE_PERF) {
+ spin_unlock_irqrestore(&drvdata->spinlock, flags);
+ dma_free_coherent(drvdata->dev, drvdata->size, vaddr, paddr);
+ return -EBUSY;
+ }
+
/*
* In sysFS mode we can have multiple writers per sink. Since this
* sink is already enabled no memory is needed and the HW need not be
@@ -143,7 +150,7 @@ out:
return 0;
}
-static void tmc_disable_etr_sink(struct coresight_device *csdev)
+static int tmc_enable_etr_sink_perf(struct coresight_device *csdev, u32 mode)
{
u32 val;
unsigned long flags;
@@ -152,16 +159,66 @@ static void tmc_disable_etr_sink(struct coresight_device *csdev)
spin_lock_irqsave(&drvdata->spinlock, flags);
if (drvdata->reading) {
spin_unlock_irqrestore(&drvdata->spinlock, flags);
+ return -EBUSY;
+ }
+
+ val = local_cmpxchg(&drvdata->mode, CS_MODE_DISABLED, mode);
+ /*
+ * In Perf mode there can be only one writer per sink. There
+ * is also no need to continue if the ETR is already operated
+ * from sysFS.
+ */
+ if (val != CS_MODE_DISABLED) {
+ spin_unlock_irqrestore(&drvdata->spinlock, flags);
+ return -EBUSY;
+ }
+
+ tmc_etr_enable_hw(drvdata);
+ spin_unlock_irqrestore(&drvdata->spinlock, flags);
+
+ return 0;
+}
+
+static int tmc_enable_etr_sink(struct coresight_device *csdev, u32 mode)
+{
+ switch (mode) {
+ case CS_MODE_SYSFS:
+ return tmc_enable_etr_sink_sysfs(csdev, mode);
+ case CS_MODE_PERF:
+ return tmc_enable_etr_sink_perf(csdev, mode);
+ }
+
+ /* We shouldn't be here */
+ return -EINVAL;
+}
+
+static void tmc_disable_etr_sink(struct coresight_device *csdev)
+{
+ u32 mode;
+ unsigned long flags;
+ struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+
+ spin_lock_irqsave(&drvdata->spinlock, flags);
+ if (drvdata->reading) {
+ spin_unlock_irqrestore(&drvdata->spinlock, flags);
return;
}
- val = local_cmpxchg(&drvdata->mode, CS_MODE_SYSFS, CS_MODE_DISABLED);
- /* Nothing to do, the TMC was already disabled */
- if (val == CS_MODE_DISABLED)
+ mode = local_xchg(&drvdata->mode, CS_MODE_DISABLED);
+ /* Nothing to do, the ETR was already disabled */
+ if (mode == CS_MODE_DISABLED)
goto out;
+ /* The engine has to be stopped in both sysFS and Perf mode */
tmc_etr_disable_hw(drvdata);
- tmc_etr_dump_hw(drvdata);
+
+ /*
+ * If we operated from sysFS, dump the trace data for retrieval
+ * via /dev/. From Perf trace data is handled via the Perf ring
+ * buffer.
+ */
+ if (mode == CS_MODE_SYSFS)
+ tmc_etr_dump_hw(drvdata);
out:
spin_unlock_irqrestore(&drvdata->spinlock, flags);
@@ -184,7 +241,13 @@ int tmc_read_prepare_etr(struct tmc_drvdata *drvdata)
spin_lock_irqsave(&drvdata->spinlock, flags);
- /* The TMC isn't enabled, so there is no need to disable it */
+ /* Don't interfere if operated from Perf */
+ if (local_read(&drvdata->mode) == CS_MODE_PERF) {
+ spin_unlock_irqrestore(&drvdata->spinlock, flags);
+ return -EBUSY;
+ }
+
+ /* The ETR isn't enabled, so there is no need to disable it */
if (local_read(&drvdata->mode) == CS_MODE_DISABLED) {
/*
* The ETR is disabled already. If drvdata::buf is NULL
--
2.1.4
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