On 12/04/16 18:54, Mathieu Poirier wrote:
Moving tmc_drvdata::enable to a local_t mode. That way the
sink interface is aware of it's orgin and the foundation for
mutual exclusion between the sysFS and Perf interface can be
laid out.
Signed-off-by: Mathieu Poirier <[email protected]>
---
drivers/hwtracing/coresight/coresight-tmc-etf.c | 28 ++++++++++++++++++-------
drivers/hwtracing/coresight/coresight-tmc-etr.c | 24 ++++++++++++++++-----
drivers/hwtracing/coresight/coresight-tmc.h | 4 ++--
3 files changed, 42 insertions(+), 14 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c
b/drivers/hwtracing/coresight/coresight-tmc-etf.c
index 7cb287ef7b9e..5908000e1ae0 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etf.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c
@@ -110,6 +110,7 @@ static int tmc_enable_etf_sink(struct coresight_device
*csdev, u32 mode)
{
bool allocated = false;
char *buf = NULL;
+ u32 val;
unsigned long flags;
struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
@@ -146,6 +147,15 @@ fast_path:
return -EBUSY;
}
+ 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)
+ goto out;
+
We are not dropping the spinlock in this case. Are we ?
/*
* If drvdata::buf isn't NULL, memory was allocated for a previous
* trace run but wasn't read. If so simply zero-out the memory.
@@ -163,9 +173,9 @@ fast_path:
}
tmc_etb_enable_hw(drvdata);
- drvdata->enable = true;
spin_unlock_irqrestore(&drvdata->spinlock, flags);
+out:
/* Free memory outside the spinlock if need be */
if (!allocated && buf)
kfree(buf);
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c
b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index 6022ff26deba..8e6fe267195a 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -85,6 +85,7 @@ static void tmc_etr_disable_hw(struct tmc_drvdata *drvdata)
static int tmc_enable_etr_sink(struct coresight_device *csdev, u32 mode)
{
bool allocated = false;
+ u32 val;
unsigned long flags;
void __iomem *vaddr = NULL;
dma_addr_t paddr;
@@ -125,6 +126,15 @@ fast_path:
return -EBUSY;
}
+ 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)
+ goto out;
+
Same as above, we should drop the locks in this case.
@@ -140,9 +150,9 @@ fast_path:
memset(drvdata->vaddr, 0, drvdata->size);
tmc_etr_enable_hw(drvdata);
- drvdata->enable = true;
spin_unlock_irqrestore(&drvdata->spinlock, flags);
+out:
/* Free memory outside the spinlock if need be */
if (!allocated && vaddr)
dma_free_coherent(drvdata->dev, drvdata->size, vaddr, paddr);
@@ -153,6 +163,7 @@ fast_path:
diff --git a/drivers/hwtracing/coresight/coresight-tmc.h
b/drivers/hwtracing/coresight/coresight-tmc.h
index 80096fa75326..821bdf150ac9 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.h
+++ b/drivers/hwtracing/coresight/coresight-tmc.h
@@ -100,7 +100,7 @@ enum tmc_mem_intf_width {
* @paddr: DMA start location in RAM.
* @vaddr: virtual representation of @paddr.
* @size: @buf size.
- * @enable: this TMC is being used.
+ * @mode: how this TMC is being used.
* @config_type: TMC variant, must be of type @tmc_config_type.
* @trigger_cntr: amount of words to store after a trigger.
*/
@@ -116,7 +116,7 @@ struct tmc_drvdata {
dma_addr_t paddr;
void __iomem *vaddr;
u32 size;
- bool enable;
+ local_t mode;
Since we always deal with the mode under the spinlock, do we really need this to
be local_t ? Or do we plan to get rid of the lock ?
Suzuki
