coresight: etm4x: Handle access to TRCSSPCICRn

TRCSSPCICR<n> is present only if all of the following are true:
	TRCIDR4.NUMSSCC > n.
	TRCIDR4.NUMPC > 0b0000 .
	TRCSSCSR<n>.PC == 0b1

Add a helper function to check all the conditions.

Link: https://lore.kernel.org/r/20210110224850.1880240-2-suzuki.poulose@arm.com
Cc: Mike Leach <mike.leach@linaro.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/20210201181351.1475223-4-mathieu.poirier@linaro.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

@@ -59,6 +59,22 @@ static u64 etm4_get_access_type(struct etmv4_config *config);
 
 static enum cpuhp_state hp_online;
 
+/*
+ * Check if TRCSSPCICRn(i) is implemented for a given instance.
+ *
+ * TRCSSPCICRn is implemented only if :
+ *	TRCSSPCICR<n> is present only if all of the following are true:
+ *		TRCIDR4.NUMSSCC > n.
+ *		TRCIDR4.NUMPC > 0b0000 .
+ *		TRCSSCSR<n>.PC == 0b1
+ */
+static inline bool etm4x_sspcicrn_present(struct etmv4_drvdata *drvdata, int n)
+{
+	return (n < drvdata->nr_ss_cmp) &&
+	       drvdata->nr_pe &&
+	       (drvdata->config.ss_status[n] & TRCSSCSRn_PC);
+}
+
 static void etm4_os_unlock(struct etmv4_drvdata *drvdata)
 {
 	/* Writing 0 to TRCOSLAR unlocks the trace registers */
@@ -270,8 +286,9 @@ static int etm4_enable_hw(struct etmv4_drvdata *drvdata)
 			       drvdata->base + TRCSSCCRn(i));
 		writel_relaxed(config->ss_status[i],
 			       drvdata->base + TRCSSCSRn(i));
-		writel_relaxed(config->ss_pe_cmp[i],
-			       drvdata->base + TRCSSPCICRn(i));
+		if (etm4x_sspcicrn_present(drvdata, i))
+			writel_relaxed(config->ss_pe_cmp[i],
+				       drvdata->base + TRCSSPCICRn(i));
 	}
 	for (i = 0; i < drvdata->nr_addr_cmp; i++) {
 		writeq_relaxed(config->addr_val[i],
@@ -1324,7 +1341,8 @@ static int etm4_cpu_save(struct etmv4_drvdata *drvdata)
 	for (i = 0; i < drvdata->nr_ss_cmp; i++) {
 		state->trcssccr[i] = readl(drvdata->base + TRCSSCCRn(i));
 		state->trcsscsr[i] = readl(drvdata->base + TRCSSCSRn(i));
-		state->trcsspcicr[i] = readl(drvdata->base + TRCSSPCICRn(i));
+		if (etm4x_sspcicrn_present(drvdata, i))
+			state->trcsspcicr[i] = readl(drvdata->base + TRCSSPCICRn(i));
 	}
 
 	for (i = 0; i < drvdata->nr_addr_cmp * 2; i++) {
@@ -1440,8 +1458,9 @@ static void etm4_cpu_restore(struct etmv4_drvdata *drvdata)
 			       drvdata->base + TRCSSCCRn(i));
 		writel_relaxed(state->trcsscsr[i],
 			       drvdata->base + TRCSSCSRn(i));
-		writel_relaxed(state->trcsspcicr[i],
-			       drvdata->base + TRCSSPCICRn(i));
+		if (etm4x_sspcicrn_present(drvdata, i))
+			writel_relaxed(state->trcsspcicr[i],
+				       drvdata->base + TRCSSPCICRn(i));
 	}
 
 	for (i = 0; i < drvdata->nr_addr_cmp * 2; i++) {

drivers/hwtracing/coresight/coresight-etm4x.h

@@ -179,6 +179,8 @@
 #define TRCSTATR_PMSTABLE_BIT		1
 #define ETM_DEFAULT_ADDR_COMP		0
 
+#define TRCSSCSRn_PC			BIT(3)
+
 /* PowerDown Control Register bits */
 #define TRCPDCR_PU			BIT(3)