linux-kernel - [RFC PATCH] coresight: dynamic-replicator: Fix handling of multiple connections

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Date:   Sun,  5 Apr 2020 15:58:19 +0530
From:   Sai Prakash Ranjan <saiprakash.ranjan@...eaurora.org>
To:     Mathieu Poirier <mathieu.poirier@...aro.org>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Leo Yan <leo.yan@...aro.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Mike Leach <mike.leach@...aro.org>,
        Stephen Boyd <swboyd@...omium.org>
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-arm-msm@...r.kernel.org,
        Sai Prakash Ranjan <saiprakash.ranjan@...eaurora.org>
Subject: [RFC PATCH] coresight: dynamic-replicator: Fix handling of multiple connections

Since commit 30af4fb619e5 ("coresight: dynamic-replicator:
Handle multiple connections"), we do not make sure that
the other port is disabled when the dynamic replicator is
enabled. This is seen to cause the CPU hardlockup atleast
on SC7180 SoC when enabling ETM with ETR as the sink via
sysfs.

  Kernel panic - not syncing: Watchdog detected hard LOCKUP on cpu 0
  CPU: 7 PID: 0 Comm: swapper/7 Tainted: G S  B             5.4.25 #100
  Hardware name: Qualcomm Technologies, Inc. SC7180 IDP (DT)
  Call trace:
   dump_backtrace+0x0/0x188
   show_stack+0x20/0x2c
   dump_stack+0xdc/0x144
   panic+0x168/0x370
   arch_seccomp_spec_mitigate+0x0/0x14
   watchdog_timer_fn+0x68/0x290
   __hrtimer_run_queues+0x264/0x498
   hrtimer_interrupt+0xf0/0x22c
   arch_timer_handler_phys+0x40/0x50
   handle_percpu_devid_irq+0x8c/0x158
   __handle_domain_irq+0x84/0xc4
   gic_handle_irq+0x100/0x1c4
   el1_irq+0xbc/0x180
   arch_cpu_idle+0x3c/0x5c
   default_idle_call+0x1c/0x38
   do_idle+0x100/0x280
   cpu_startup_entry+0x24/0x28
   secondary_start_kernel+0x15c/0x170
  SMP: stopping secondary CPUs

Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@...eaurora.org>
---
 .../hwtracing/coresight/coresight-replicator.c    | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-replicator.c b/drivers/hwtracing/coresight/coresight-replicator.c
index e7dc1c31d20d..f4eaa38f8f43 100644
--- a/drivers/hwtracing/coresight/coresight-replicator.c
+++ b/drivers/hwtracing/coresight/coresight-replicator.c
@@ -66,14 +66,16 @@ static int dynamic_replicator_enable(struct replicator_drvdata *drvdata,
 				     int inport, int outport)
 {
 	int rc = 0;
-	u32 reg;
+	u32 reg0, reg1;

 	switch (outport) {
 	case 0:
-		reg = REPLICATOR_IDFILTER0;
+		reg0 = REPLICATOR_IDFILTER0;
+		reg1 = REPLICATOR_IDFILTER1;
 		break;
 	case 1:
-		reg = REPLICATOR_IDFILTER1;
+		reg0 = REPLICATOR_IDFILTER1;
+		reg1 = REPLICATOR_IDFILTER0;
 		break;
 	default:
 		WARN_ON(1);
@@ -87,8 +89,11 @@ static int dynamic_replicator_enable(struct replicator_drvdata *drvdata,
 		rc = coresight_claim_device_unlocked(drvdata->base);

 	/* Ensure that the outport is enabled. */
-	if (!rc)
-		writel_relaxed(0x00, drvdata->base + reg);
+	if (!rc) {
+		writel_relaxed(0x00, drvdata->base + reg0);
+		writel_relaxed(0xff, drvdata->base + reg1);
+	}
+
 	CS_LOCK(drvdata->base);

 	return rc;
-- 
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