coresight: etm4x: Handle TRCVIPCSSCTLR accesses

TRCVIPCSSCTLR is not present if the TRCIDR4.NUMPC > 0. Thus we
should only access the register if it is present, preventing
any undesired behavior.

Cc: stable@vger.kernel.org
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20201127175256.1092685-8-mathieu.poirier@linaro.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/hwtracing/coresight/coresight-etm4x-core.c

@@ -141,6 +141,7 @@ static int etm4_enable_hw(struct etmv4_drvdata *drvdata)
 	writel_relaxed(config->viiectlr, drvdata->base + TRCVIIECTLR);
 	writel_relaxed(config->vissctlr,
 		       drvdata->base + TRCVISSCTLR);
+	if (drvdata->nr_pe_cmp)
 		writel_relaxed(config->vipcssctlr,
 			       drvdata->base + TRCVIPCSSCTLR);
 	for (i = 0; i < drvdata->nrseqstate - 1; i++)
@@ -1202,6 +1203,7 @@ static int etm4_cpu_save(struct etmv4_drvdata *drvdata)
 	state->trcvictlr = readl(drvdata->base + TRCVICTLR);
 	state->trcviiectlr = readl(drvdata->base + TRCVIIECTLR);
 	state->trcvissctlr = readl(drvdata->base + TRCVISSCTLR);
+	if (drvdata->nr_pe_cmp)
 		state->trcvipcssctlr = readl(drvdata->base + TRCVIPCSSCTLR);
 	state->trcvdctlr = readl(drvdata->base + TRCVDCTLR);
 	state->trcvdsacctlr = readl(drvdata->base + TRCVDSACCTLR);
@@ -1310,6 +1312,7 @@ static void etm4_cpu_restore(struct etmv4_drvdata *drvdata)
 	writel_relaxed(state->trcvictlr, drvdata->base + TRCVICTLR);
 	writel_relaxed(state->trcviiectlr, drvdata->base + TRCVIIECTLR);
 	writel_relaxed(state->trcvissctlr, drvdata->base + TRCVISSCTLR);
+	if (drvdata->nr_pe_cmp)
 		writel_relaxed(state->trcvipcssctlr, drvdata->base + TRCVIPCSSCTLR);
 	writel_relaxed(state->trcvdctlr, drvdata->base + TRCVDCTLR);
 	writel_relaxed(state->trcvdsacctlr, drvdata->base + TRCVDSACCTLR);