coresight: tmc-etr: Disallow perf mode

We don't support ETR in perf mode yet. So, don't
even try to enable the hardware, even by mistake.

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>

drivers/hwtracing/coresight/coresight-tmc-etr.c

@@ -211,32 +211,8 @@ out:
 
 static int tmc_enable_etr_sink_perf(struct coresight_device *csdev)
 {
-	int ret = 0;
-	unsigned long flags;
-	struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
-
-	spin_lock_irqsave(&drvdata->spinlock, flags);
-	if (drvdata->reading) {
-		ret = -EINVAL;
-		goto out;
-	}
-
-	/*
-	 * 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 (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);
-
-	return ret;
+	/* We don't support perf mode yet ! */
+	return -EINVAL;
 }
 
 static int tmc_enable_etr_sink(struct coresight_device *csdev, u32 mode)