[PATCH 2/2] coresight: tmc: Add shutdown callback for TMC ETR/ETF

[Sai Prakash Ranjan]

Implement a shutdown callback to ensure ETR/ETF hardware is
properly shutdown in reboot/shutdown path. This is required
for ETR/ETF which has SMMU address translation enabled like
on SC7180 SoC and few others. If the hardware is still accessing
memory after SMMU translation is disabled as part of SMMU
shutdown callback in system reboot or shutdown path, then
IOVAs(I/O virtual address) which it was using will go on the bus
as the physical addresses which might result in unknown crashes
(NoC/interconnect errors). So we make sure from this shutdown
callback that the ETR/ETF is shutdown before SMMU translation is
disabled and device_link in SMMU driver will take care of ordering
of shutdown callbacks such that SMMU shutdown callback is not
called before any of its consumer shutdown callbacks.

Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@xxxxxxxxxxxxxx>
---
 .../hwtracing/coresight/coresight-tmc-etf.c   |  4 +--
 .../hwtracing/coresight/coresight-tmc-etr.c   |  2 +-
 drivers/hwtracing/coresight/coresight-tmc.c   | 29 +++++++++++++++++++
 drivers/hwtracing/coresight/coresight-tmc.h   |  3 ++
 4 files changed, 35 insertions(+), 3 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c
index 36cce2bfb744..cba3e7592820 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etf.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c
@@ -85,7 +85,7 @@ static void __tmc_etb_disable_hw(struct tmc_drvdata *drvdata)
 	CS_LOCK(drvdata->base);
 }
 
-static void tmc_etb_disable_hw(struct tmc_drvdata *drvdata)
+void tmc_etb_disable_hw(struct tmc_drvdata *drvdata)
 {
 	__tmc_etb_disable_hw(drvdata);
 	coresight_disclaim_device(drvdata->base);
@@ -118,7 +118,7 @@ static int tmc_etf_enable_hw(struct tmc_drvdata *drvdata)
 	return 0;
 }
 
-static void tmc_etf_disable_hw(struct tmc_drvdata *drvdata)
+void tmc_etf_disable_hw(struct tmc_drvdata *drvdata)
 {
 	CS_UNLOCK(drvdata->base);
 
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index 625882bc8b08..b29c2db94d96 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -1110,7 +1110,7 @@ static void __tmc_etr_disable_hw(struct tmc_drvdata *drvdata)
 
 }
 
-static void tmc_etr_disable_hw(struct tmc_drvdata *drvdata)
+void tmc_etr_disable_hw(struct tmc_drvdata *drvdata)
 {
 	__tmc_etr_disable_hw(drvdata);
 	/* Disable CATU device if this ETR is connected to one */
diff --git a/drivers/hwtracing/coresight/coresight-tmc.c b/drivers/hwtracing/coresight/coresight-tmc.c
index 5a271ebc4585..7e687a356fe0 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.c
+++ b/drivers/hwtracing/coresight/coresight-tmc.c
@@ -540,6 +540,34 @@ static int tmc_probe(struct amba_device *adev, const struct amba_id *id)
 	return ret;
 }
 
+static void tmc_shutdown(struct amba_device *adev)
+{
+	struct tmc_drvdata *drvdata = amba_get_drvdata(adev);
+
+	if (!drvdata->enable)
+		goto out;
+
+	/*
+	 * We do not care about the active trace sessions here
+	 * since the system is going down unlike remove callback,
+	 * just make sure that the hardware is shutdown.
+	 */
+	switch (drvdata->config_type) {
+	case TMC_CONFIG_TYPE_ETB:
+		tmc_etb_disable_hw(drvdata);
+		break;
+	case TMC_CONFIG_TYPE_ETF:
+		tmc_etf_disable_hw(drvdata);
+		break;
+	case TMC_CONFIG_TYPE_ETR:
+		tmc_etr_disable_hw(drvdata);
+	}
+
+out:
+	misc_deregister(&drvdata->miscdev);
+	coresight_unregister(drvdata->csdev);
+}
+
 static const struct amba_id tmc_ids[] = {
 	CS_AMBA_ID(0x000bb961),
 	/* Coresight SoC 600 TMC-ETR/ETS */
@@ -558,6 +586,7 @@ static struct amba_driver tmc_driver = {
 		.suppress_bind_attrs = true,
 	},
 	.probe		= tmc_probe,
+	.shutdown	= tmc_shutdown,
 	.id_table	= tmc_ids,
 };
 builtin_amba_driver(tmc_driver);
diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h
index d156860495c7..f4f56c474e58 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.h
+++ b/drivers/hwtracing/coresight/coresight-tmc.h
@@ -262,6 +262,8 @@ u32 tmc_get_memwidth_mask(struct tmc_drvdata *drvdata);
 /* ETB/ETF functions */
 int tmc_read_prepare_etb(struct tmc_drvdata *drvdata);
 int tmc_read_unprepare_etb(struct tmc_drvdata *drvdata);
+void tmc_etb_disable_hw(struct tmc_drvdata *drvdata);
+void tmc_etf_disable_hw(struct tmc_drvdata *drvdata);
 extern const struct coresight_ops tmc_etb_cs_ops;
 extern const struct coresight_ops tmc_etf_cs_ops;
 
@@ -270,6 +272,7 @@ ssize_t tmc_etb_get_sysfs_trace(struct tmc_drvdata *drvdata,
 /* ETR functions */
 int tmc_read_prepare_etr(struct tmc_drvdata *drvdata);
 int tmc_read_unprepare_etr(struct tmc_drvdata *drvdata);
+void tmc_etr_disable_hw(struct tmc_drvdata *drvdata);
 extern const struct coresight_ops tmc_etr_cs_ops;
 ssize_t tmc_etr_get_sysfs_trace(struct tmc_drvdata *drvdata,
 				loff_t pos, size_t len, char **bufpp);
-- 
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