UPSTREAM: coresight: tmc: Cleanup operation mode handling
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@broadcom.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 297ab90f15f6222408380bbf4e8cbff57b02060d)
Change-Id: I5f217d87f2e3a3e18764c1b5f909c88bf1a9dc91
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index 886ea83..f23ef0c 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -86,7 +86,7 @@
* 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 @@
{
int ret = 0;
bool used = false;
- long val;
unsigned long flags;
void __iomem *vaddr = NULL;
dma_addr_t paddr;
@@ -134,13 +133,12 @@
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 @@
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 @@
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);
@@ -188,17 +186,17 @@
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) {
ret = -EINVAL;
goto out;
}
+ drvdata->mode = CS_MODE_PERF;
tmc_etr_enable_hw(drvdata);
out:
spin_unlock_irqrestore(&drvdata->spinlock, flags);
@@ -221,7 +219,6 @@
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 @@
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 @@
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 @@
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 @@
}
/* 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 @@
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(),