Qualcomm implements an extended variant of the ARM CoreSight CTI with a
different register layout and vendor-specific behavior. While the
programming model remains largely compatible, the register offsets differ
from the standard ARM CTI and require explicit handling.

Detect Qualcomm CTIs via the DEVARCH register and record this in the CTI
driver data. Introduce a small mapping layer to translate standard CTI
register offsets to Qualcomm-specific offsets, allowing the rest of the
driver to use a common register access path.

Additionally, handle a Qualcomm-specific quirk where the CLAIMSET
register is incorrectly initialized to a non-zero value, which can cause
tools or drivers to assume the component is already claimed. Clear the
register during probe to reflect the actual unclaimed state.

No functional change is intended for standard ARM CTI devices.

Co-developed-by: Jinlong Mao <jinlong.mao@oss.qualcomm.com>
Signed-off-by: Jinlong Mao <jinlong.mao@oss.qualcomm.com>
Signed-off-by: Yingchao Deng <yingchao.deng@oss.qualcomm.com>
---
 drivers/hwtracing/coresight/coresight-cti-core.c | 26 +++++++++-
 drivers/hwtracing/coresight/coresight-cti.h      |  1 +
 drivers/hwtracing/coresight/qcom-cti.h           | 65 ++++++++++++++++++++++++
 3 files changed, 91 insertions(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-cti-core.c b/drivers/hwtracing/coresight/coresight-cti-core.c
index 023993475a2e..afa83d411a4a 100644
--- a/drivers/hwtracing/coresight/coresight-cti-core.c
+++ b/drivers/hwtracing/coresight/coresight-cti-core.c
@@ -21,6 +21,7 @@
 
 #include "coresight-priv.h"
 #include "coresight-cti.h"
+#include "qcom-cti.h"
 
 /*
  * CTI devices can be associated with a PE, or be connected to CoreSight
@@ -47,6 +48,10 @@ static void __iomem *cti_reg_addr(struct cti_drvdata *drvdata, u32 reg)
 	u32 offset = CTI_REG_CLR_NR(reg);
 	u32 nr = CTI_REG_GET_NR(reg);
 
+	/* convert to qcom specific offset */
+	if (unlikely(drvdata->is_qcom_cti))
+		offset = cti_qcom_reg_off(offset);
+
 	return drvdata->base + offset + sizeof(u32) * nr;
 }
 
@@ -170,6 +175,9 @@ void cti_write_intack(struct device *dev, u32 ackval)
 /* DEVID[19:16] - number of CTM channels */
 #define CTI_DEVID_CTMCHANNELS(devid_val) ((int) BMVAL(devid_val, 16, 19))
 
+/* DEVARCH[31:21] - ARCHITECT */
+#define CTI_DEVARCH_ARCHITECT(devarch_val) ((int)BMVAL(devarch_val, 21, 31))
+
 static int cti_set_default_config(struct device *dev,
 				  struct cti_drvdata *drvdata)
 {
@@ -698,6 +706,7 @@ static int cti_probe(struct amba_device *adev, const struct amba_id *id)
 	struct coresight_desc cti_desc;
 	struct coresight_platform_data *pdata = NULL;
 	struct resource *res = &adev->res;
+	u32 devarch;
 
 	/* driver data*/
 	drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
@@ -722,6 +731,20 @@ static int cti_probe(struct amba_device *adev, const struct amba_id *id)
 
 	raw_spin_lock_init(&drvdata->spinlock);
 
+	devarch = readl_relaxed(drvdata->base + CORESIGHT_DEVARCH);
+	if (CTI_DEVARCH_ARCHITECT(devarch) == ARCHITECT_QCOM) {
+		drvdata->is_qcom_cti = true;
+		/*
+		 * QCOM CTI does not implement Claimtag functionality as
+		 * per CoreSight specification, but its CLAIMSET register
+		 * is incorrectly initialized to 0xF. This can mislead
+		 * tools or drivers into thinking the component is claimed.
+		 *
+		 * Reset CLAIMSET to 0 to reflect that no claims are active.
+		 */
+		writel_relaxed(0, drvdata->base + CORESIGHT_CLAIMSET);
+	}
+
 	/* initialise CTI driver config values */
 	ret = cti_set_default_config(dev, drvdata);
 	if (ret)
@@ -778,7 +801,8 @@ static int cti_probe(struct amba_device *adev, const struct amba_id *id)
 
 	/* all done - dec pm refcount */
 	pm_runtime_put(&adev->dev);
-	dev_info(&drvdata->csdev->dev, "CTI initialized\n");
+	dev_info(&drvdata->csdev->dev,
+		 "%sCTI initialized\n", drvdata->is_qcom_cti ? "QCOM " : "");
 	return 0;
 }
 
diff --git a/drivers/hwtracing/coresight/coresight-cti.h b/drivers/hwtracing/coresight/coresight-cti.h
index 21bcdedcb95f..9c0896b17c24 100644
--- a/drivers/hwtracing/coresight/coresight-cti.h
+++ b/drivers/hwtracing/coresight/coresight-cti.h
@@ -187,6 +187,7 @@ struct cti_drvdata {
 	raw_spinlock_t spinlock;
 	struct cti_config config;
 	struct list_head node;
+	bool is_qcom_cti;
 };
 
 /*
diff --git a/drivers/hwtracing/coresight/qcom-cti.h b/drivers/hwtracing/coresight/qcom-cti.h
new file mode 100644
index 000000000000..21a33b759b36
--- /dev/null
+++ b/drivers/hwtracing/coresight/qcom-cti.h
@@ -0,0 +1,65 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
+ */
+
+#ifndef _CORESIGHT_QCOM_CTI_H
+#define _CORESIGHT_QCOM_CTI_H
+
+#include "coresight-cti.h"
+
+#define ARCHITECT_QCOM 0x477
+
+/* CTI programming registers */
+#define    QCOM_CTIINTACK	0x020
+#define    QCOM_CTIAPPSET	0x004
+#define    QCOM_CTIAPPCLEAR	0x008
+#define    QCOM_CTIAPPPULSE	0x00C
+#define    QCOM_CTIINEN		0x400
+#define    QCOM_CTIOUTEN        0x800
+#define    QCOM_CTITRIGINSTATUS	0x040
+#define    QCOM_CTITRIGOUTSTATUS	0x060
+#define    QCOM_CTICHINSTATUS	0x080
+#define    QCOM_CTICHOUTSTATUS	0x084
+#define    QCOM_CTIGATE		0x088
+#define    QCOM_ASICCTL		0x08c
+/* Integration test registers */
+#define    QCOM_ITCHINACK	0xE70
+#define    QCOM_ITTRIGINACK	0xE80
+#define    QCOM_ITCHOUT		0xE74
+#define    QCOM_ITTRIGOUT	0xEA0
+#define    QCOM_ITCHOUTACK	0xE78
+#define    QCOM_ITTRIGOUTACK	0xEC0
+#define    QCOM_ITCHIN		0xE7C
+#define    QCOM_ITTRIGIN	0xEE0
+
+static noinline u32 cti_qcom_reg_off(u32 offset)
+{
+	switch (offset) {
+	case CTIINTACK:		return QCOM_CTIINTACK;
+	case CTIAPPSET:		return QCOM_CTIAPPSET;
+	case CTIAPPCLEAR:	return QCOM_CTIAPPCLEAR;
+	case CTIAPPPULSE:	return QCOM_CTIAPPPULSE;
+	case CTIINEN:		return QCOM_CTIINEN;
+	case CTIOUTEN:		return QCOM_CTIOUTEN;
+	case CTITRIGINSTATUS:	return QCOM_CTITRIGINSTATUS;
+	case CTITRIGOUTSTATUS:	return QCOM_CTITRIGOUTSTATUS;
+	case CTICHINSTATUS:	return QCOM_CTICHINSTATUS;
+	case CTICHOUTSTATUS:	return QCOM_CTICHOUTSTATUS;
+	case CTIGATE:		return QCOM_CTIGATE;
+	case ASICCTL:		return QCOM_ASICCTL;
+	case ITCHINACK:		return QCOM_ITCHINACK;
+	case ITTRIGINACK:	return QCOM_ITTRIGINACK;
+	case ITCHOUT:		return QCOM_ITCHOUT;
+	case ITTRIGOUT:		return QCOM_ITTRIGOUT;
+	case ITCHOUTACK:	return QCOM_ITCHOUTACK;
+	case ITTRIGOUTACK:	return QCOM_ITTRIGOUTACK;
+	case ITCHIN:		return QCOM_ITCHIN;
+	case ITTRIGIN:		return QCOM_ITTRIGIN;
+
+	default:
+		return offset;
+	}
+}
+
+#endif  /* _CORESIGHT_QCOM_CTI_H */

-- 
2.43.0