[PATCH] coresight: tmc: Cleanup operation mode handling
Suzuki K Poulose
suzuki.poulose at arm.com
Wed Sep 14 06:53:50 PDT 2016
The mode of operation of the TMC tracked in drvdata->mode is defined
as a local_t type. This is always checked and modified under the
drvdata->spinlock and hence we don't need local_t for it and the
unnecessary synchronisation instructions that comes with it. This
change makes the code a bit more cleaner.
Also fixes the order in which we update the drvdata->mode to
CS_MODE_DISABLED. i.e, in tmc_disable_etX_sink we change the
mode to CS_MODE_DISABLED before invoking tmc_disable_etX_hw()
which in turn depends on the mode to decide whether to dump the
trace to a buffer.
Applies on mathieu's coresight/next tree [1]
https://git.linaro.org/kernel/coresight.git next
Reported-by: Venkatesh Vivekanandan <venkatesh.vivekanandan at broadcom.com>
Cc: Mathieu Poirier <mathieu.poirier at linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose at arm.com>
---
drivers/hwtracing/coresight/coresight-tmc-etf.c | 32 +++++++++++--------------
drivers/hwtracing/coresight/coresight-tmc-etr.c | 30 ++++++++++-------------
drivers/hwtracing/coresight/coresight-tmc.h | 2 +-
3 files changed, 28 insertions(+), 36 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c
index d6941ea..c51ce45 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etf.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c
@@ -70,7 +70,7 @@ static void tmc_etb_disable_hw(struct tmc_drvdata *drvdata)
* When operating in sysFS mode the content of the buffer needs to be
* read before the TMC is disabled.
*/
- if (local_read(&drvdata->mode) == CS_MODE_SYSFS)
+ if (drvdata->mode == CS_MODE_SYSFS)
tmc_etb_dump_hw(drvdata);
tmc_disable_hw(drvdata);
@@ -108,7 +108,6 @@ static int tmc_enable_etf_sink_sysfs(struct coresight_device *csdev, u32 mode)
int ret = 0;
bool used = false;
char *buf = NULL;
- long val;
unsigned long flags;
struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
@@ -138,13 +137,12 @@ static int tmc_enable_etf_sink_sysfs(struct coresight_device *csdev, u32 mode)
goto out;
}
- val = local_xchg(&drvdata->mode, mode);
/*
* 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
* touched.
*/
- if (val == CS_MODE_SYSFS)
+ if (drvdata->mode == CS_MODE_SYSFS)
goto out;
/*
@@ -163,6 +161,7 @@ static int tmc_enable_etf_sink_sysfs(struct coresight_device *csdev, u32 mode)
drvdata->buf = buf;
}
+ drvdata->mode = CS_MODE_SYSFS;
tmc_etb_enable_hw(drvdata);
out:
spin_unlock_irqrestore(&drvdata->spinlock, flags);
@@ -180,7 +179,6 @@ out:
static int tmc_enable_etf_sink_perf(struct coresight_device *csdev, u32 mode)
{
int ret = 0;
- long val;
unsigned long flags;
struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
@@ -194,17 +192,17 @@ static int tmc_enable_etf_sink_perf(struct coresight_device *csdev, u32 mode)
goto out;
}
- val = local_xchg(&drvdata->mode, 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) {
+ if (drvdata->mode != CS_MODE_DISABLED) {
ret = -EINVAL;
goto out;
}
+ drvdata->mode = mode;
tmc_etb_enable_hw(drvdata);
out:
spin_unlock_irqrestore(&drvdata->spinlock, flags);
@@ -227,7 +225,6 @@ static int tmc_enable_etf_sink(struct coresight_device *csdev, u32 mode)
static void tmc_disable_etf_sink(struct coresight_device *csdev)
{
- long val;
unsigned long flags;
struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
@@ -237,10 +234,11 @@ static void tmc_disable_etf_sink(struct coresight_device *csdev)
return;
}
- val = local_xchg(&drvdata->mode, CS_MODE_DISABLED);
/* Disable the TMC only if it needs to */
- if (val != CS_MODE_DISABLED)
+ if (drvdata->mode != CS_MODE_DISABLED) {
tmc_etb_disable_hw(drvdata);
+ drvdata->mode = CS_MODE_DISABLED;
+ }
spin_unlock_irqrestore(&drvdata->spinlock, flags);
@@ -260,7 +258,7 @@ static int tmc_enable_etf_link(struct coresight_device *csdev,
}
tmc_etf_enable_hw(drvdata);
- local_set(&drvdata->mode, CS_MODE_SYSFS);
+ drvdata->mode = CS_MODE_SYSFS;
spin_unlock_irqrestore(&drvdata->spinlock, flags);
dev_info(drvdata->dev, "TMC-ETF enabled\n");
@@ -279,8 +277,8 @@ static void tmc_disable_etf_link(struct coresight_device *csdev,
return;
}
+ drvdata->mode = CS_MODE_DISABLED;
tmc_etf_disable_hw(drvdata);
- local_set(&drvdata->mode, CS_MODE_DISABLED);
spin_unlock_irqrestore(&drvdata->spinlock, flags);
dev_info(drvdata->dev, "TMC disabled\n");
@@ -383,7 +381,7 @@ static void tmc_update_etf_buffer(struct coresight_device *csdev,
return;
/* This shouldn't happen */
- if (WARN_ON_ONCE(local_read(&drvdata->mode) != CS_MODE_PERF))
+ if (WARN_ON_ONCE(drvdata->mode != CS_MODE_PERF))
return;
CS_UNLOCK(drvdata->base);
@@ -504,7 +502,6 @@ const struct coresight_ops tmc_etf_cs_ops = {
int tmc_read_prepare_etb(struct tmc_drvdata *drvdata)
{
- long val;
enum tmc_mode mode;
int ret = 0;
unsigned long flags;
@@ -528,9 +525,8 @@ int tmc_read_prepare_etb(struct tmc_drvdata *drvdata)
goto out;
}
- val = local_read(&drvdata->mode);
/* Don't interfere if operated from Perf */
- if (val == CS_MODE_PERF) {
+ if (drvdata->mode == CS_MODE_PERF) {
ret = -EINVAL;
goto out;
}
@@ -542,7 +538,7 @@ int tmc_read_prepare_etb(struct tmc_drvdata *drvdata)
}
/* Disable the TMC if need be */
- if (val == CS_MODE_SYSFS)
+ if (drvdata->mode == CS_MODE_SYSFS)
tmc_etb_disable_hw(drvdata);
drvdata->reading = true;
@@ -573,7 +569,7 @@ int tmc_read_unprepare_etb(struct tmc_drvdata *drvdata)
}
/* Re-enable the TMC if need be */
- if (local_read(&drvdata->mode) == CS_MODE_SYSFS) {
+ if (drvdata->mode == CS_MODE_SYSFS) {
/*
* The trace run will continue with the same allocated trace
* buffer. As such zero-out the buffer so that we don't end
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index 886ea83..cf2bf60 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -86,7 +86,7 @@ static void tmc_etr_disable_hw(struct tmc_drvdata *drvdata)
* When operating in sysFS mode the content of the buffer needs to be
* read before the TMC is disabled.
*/
- if (local_read(&drvdata->mode) == CS_MODE_SYSFS)
+ if (drvdata->mode == CS_MODE_SYSFS)
tmc_etr_dump_hw(drvdata);
tmc_disable_hw(drvdata);
@@ -97,7 +97,6 @@ static int tmc_enable_etr_sink_sysfs(struct coresight_device *csdev, u32 mode)
{
int ret = 0;
bool used = false;
- long val;
unsigned long flags;
void __iomem *vaddr = NULL;
dma_addr_t paddr;
@@ -134,13 +133,12 @@ static int tmc_enable_etr_sink_sysfs(struct coresight_device *csdev, u32 mode)
goto out;
}
- val = local_xchg(&drvdata->mode, mode);
/*
* 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
* touched.
*/
- if (val == CS_MODE_SYSFS)
+ if (drvdata->mode == CS_MODE_SYSFS)
goto out;
/*
@@ -157,6 +155,7 @@ static int tmc_enable_etr_sink_sysfs(struct coresight_device *csdev, u32 mode)
memset(drvdata->vaddr, 0, drvdata->size);
+ drvdata->mode = CS_MODE_SYSFS;
tmc_etr_enable_hw(drvdata);
out:
spin_unlock_irqrestore(&drvdata->spinlock, flags);
@@ -174,7 +173,6 @@ out:
static int tmc_enable_etr_sink_perf(struct coresight_device *csdev, u32 mode)
{
int ret = 0;
- long val;
unsigned long flags;
struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
@@ -188,18 +186,18 @@ static int tmc_enable_etr_sink_perf(struct coresight_device *csdev, u32 mode)
goto out;
}
- val = local_xchg(&drvdata->mode, 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) {
+ if (drvdata->mode == CS_MODE_DISABLED) {
+ drvdata->mode = CS_MODE_PERF;
+ tmc_etr_enable_hw(drvdata);
+ } else {
ret = -EINVAL;
- goto out;
}
- tmc_etr_enable_hw(drvdata);
out:
spin_unlock_irqrestore(&drvdata->spinlock, flags);
@@ -221,7 +219,6 @@ static int tmc_enable_etr_sink(struct coresight_device *csdev, u32 mode)
static void tmc_disable_etr_sink(struct coresight_device *csdev)
{
- long val;
unsigned long flags;
struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
@@ -231,10 +228,11 @@ static void tmc_disable_etr_sink(struct coresight_device *csdev)
return;
}
- val = local_xchg(&drvdata->mode, CS_MODE_DISABLED);
/* Disable the TMC only if it needs to */
- if (val != CS_MODE_DISABLED)
+ if (drvdata->mode != CS_MODE_DISABLED) {
tmc_etr_disable_hw(drvdata);
+ drvdata->mode = CS_MODE_DISABLED;
+ }
spin_unlock_irqrestore(&drvdata->spinlock, flags);
@@ -253,7 +251,6 @@ const struct coresight_ops tmc_etr_cs_ops = {
int tmc_read_prepare_etr(struct tmc_drvdata *drvdata)
{
int ret = 0;
- long val;
unsigned long flags;
/* config types are set a boot time and never change */
@@ -266,9 +263,8 @@ int tmc_read_prepare_etr(struct tmc_drvdata *drvdata)
goto out;
}
- val = local_read(&drvdata->mode);
/* Don't interfere if operated from Perf */
- if (val == CS_MODE_PERF) {
+ if (drvdata->mode == CS_MODE_PERF) {
ret = -EINVAL;
goto out;
}
@@ -280,7 +276,7 @@ int tmc_read_prepare_etr(struct tmc_drvdata *drvdata)
}
/* Disable the TMC if need be */
- if (val == CS_MODE_SYSFS)
+ if (drvdata->mode == CS_MODE_SYSFS)
tmc_etr_disable_hw(drvdata);
drvdata->reading = true;
@@ -303,7 +299,7 @@ int tmc_read_unprepare_etr(struct tmc_drvdata *drvdata)
spin_lock_irqsave(&drvdata->spinlock, flags);
/* RE-enable the TMC if need be */
- if (local_read(&drvdata->mode) == CS_MODE_SYSFS) {
+ if (drvdata->mode == CS_MODE_SYSFS) {
/*
* The trace run will continue with the same allocated trace
* buffer. The trace buffer is cleared in tmc_etr_enable_hw(),
diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h
index 44b3ae3..51c0185 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.h
+++ b/drivers/hwtracing/coresight/coresight-tmc.h
@@ -117,7 +117,7 @@ struct tmc_drvdata {
void __iomem *vaddr;
u32 size;
u32 len;
- local_t mode;
+ u32 mode;
enum tmc_config_type config_type;
enum tmc_mem_intf_width memwidth;
u32 trigger_cntr;
--
2.7.4
More information about the linux-arm-kernel
mailing list