coresight: tmc-etr: Introduce the notion of IDR to ETR devices

In CPU-wide scenarios with an N:1 source/sink topology, sources share
the same sink.  In order to reuse the same sink for all sources an
IDR is needed to archive events that have already been accounted for.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Tested-by: Leo Yan <leo.yan@linaro.org>
Tested-by: Robert Walker <robert.walker@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/hwtracing/coresight/coresight-tmc.c

@@ -8,10 +8,12 @@
 #include <linux/init.h>
 #include <linux/types.h>
 #include <linux/device.h>
+#include <linux/idr.h>
 #include <linux/io.h>
 #include <linux/err.h>
 #include <linux/fs.h>
 #include <linux/miscdevice.h>
+#include <linux/mutex.h>
 #include <linux/property.h>
 #include <linux/uaccess.h>
 #include <linux/slab.h>
@@ -450,6 +452,8 @@ static int tmc_probe(struct amba_device *adev, const struct amba_id *id)
 					 coresight_get_uci_data(id));
 		if (ret)
 			goto out;
+		idr_init(&drvdata->idr);
+		mutex_init(&drvdata->idr_mutex);
 		break;
 	case TMC_CONFIG_TYPE_ETF:
 		desc.type = CORESIGHT_DEV_TYPE_LINKSINK;

drivers/hwtracing/coresight/coresight-tmc.h

@@ -8,7 +8,9 @@
 #define _CORESIGHT_TMC_H
 
 #include <linux/dma-mapping.h>
+#include <linux/idr.h>
 #include <linux/miscdevice.h>
+#include <linux/mutex.h>
 #include <linux/refcount.h>
 
 #define TMC_RSZ			0x004
@@ -173,6 +175,8 @@ struct etr_buf {
  * @trigger_cntr: amount of words to store after a trigger.
  * @etr_caps:	Bitmask of capabilities of the TMC ETR, inferred from the
  *		device configuration register (DEVID)
+ * @idr:	Holds etr_bufs allocated for this ETR.
+ * @idr_mutex:	Access serialisation for idr.
  * @perf_data:	PERF buffer for ETR.
  * @sysfs_data:	SYSFS buffer for ETR.
  */
@@ -194,6 +198,8 @@ struct tmc_drvdata {
 	enum tmc_mem_intf_width	memwidth;
 	u32			trigger_cntr;
 	u32			etr_caps;
+	struct idr		idr;
+	struct mutex		idr_mutex;
 	struct etr_buf		*sysfs_buf;
 	void			*perf_data;
 };