iommu: arm-smmu: add testbus support for smmuv500

add a debugfs interface to support testbus also add an interface for
dumping testbus information, module parameters tcu_testbus_sel and
tbu_testbus_sel can be used for selecting different testbuses to dump
on tcu and tbu respectively.

Change-Id: I1bf420db053458b2ce1f43dc544c0776a3f4d176
Signed-off-by: Vijayanand Jitta <vjitta@codeaurora.org>
[isaacm@codeaurora.org: introduced CONFIG_ARM_SMMU_TESTBUS_DEBUGFS]
Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>
[guptap@codeaurora.org: resolved merge conflict]
Signed-off-by: Prakash Gupta <guptap@codeaurora.org>

drivers/iommu/Kconfig

@@ -529,6 +529,15 @@ config ARM_SMMU_DISABLE_BYPASS_BY_DEFAULT
 	  'arm-smmu.disable_bypass' will continue to override this
 	  config.
 
+config ARM_SMMU_TESTBUS_DEBUGFS
+	bool "Expose testbus control debugfs nodes"
+	depends on ARM_SMMU && IOMMU_DEBUGFS
+	help
+	  Support for exposing debugfs nodes to set testbus select values
+	  for selecting a testbus to inspect for a particular TCU/TBU
+	  on an SMMU. This also exposes debugfs nodes to read testbus output
+	  after the output has been selected.
+
 config ARM_SMMU_V3
 	tristate "ARM Ltd. System MMU Version 3 (SMMUv3) Support"
 	depends on ARM64
@@ -563,6 +572,16 @@ config IOMMU_TLBSYNC_DEBUG
 
 	  If unsure, say N here.
 
+config ARM_SMMU_TESTBUS_DUMP
+	bool "ARM SMMU testbus dump"
+	depends on ARM_SMMU
+	help
+	  Enables testbus dump collection on arm smmu right after TLB
+	  sync timeout failure.
+	  Note to use this only on debug builds.
+
+	  If unsure, say N here.
+
 config QCOM_LAZY_MAPPING
 	tristate "Reference counted iommu-mapping support"
 	depends on ION

drivers/iommu/Makefile

@@ -17,7 +17,7 @@ obj-$(CONFIG_AMD_IOMMU) += amd_iommu.o amd_iommu_init.o amd_iommu_quirks.o
 obj-$(CONFIG_AMD_IOMMU_DEBUGFS) += amd_iommu_debugfs.o
 obj-$(CONFIG_AMD_IOMMU_V2) += amd_iommu_v2.o
 obj-$(CONFIG_ARM_SMMU) += qcom-arm-smmu-mod.o
-qcom-arm-smmu-mod-objs += arm-smmu.o arm-smmu-impl.o arm-smmu-qcom.o
+qcom-arm-smmu-mod-objs += arm-smmu.o arm-smmu-impl.o arm-smmu-qcom.o arm-smmu-debug.o
 obj-$(CONFIG_ARM_SMMU_V3) += arm-smmu-v3.o
 obj-$(CONFIG_DMAR_TABLE) += dmar.o
 obj-$(CONFIG_INTEL_IOMMU) += intel-iommu.o intel-pasid.o

drivers/iommu/arm-smmu-debug.c

@@ -0,0 +1,193 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2019, The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/kernel.h>
+#include <linux/io.h>
+#include <linux/device.h>
+#include "arm-smmu.h"
+#include "arm-smmu-debug.h"
+
+
+u32 arm_smmu_debug_tbu_testbus_select(void __iomem *tbu_base,
+				bool write, u32 val)
+{
+	if (write) {
+		writel_relaxed(val, tbu_base + DEBUG_TESTBUS_SEL_TBU);
+		/* Make sure tbu select register is written to */
+		wmb();
+	} else {
+		return readl_relaxed(tbu_base + DEBUG_TESTBUS_SEL_TBU);
+	}
+	return 0;
+}
+
+u32 arm_smmu_debug_tbu_testbus_output(void __iomem *tbu_base)
+{
+	return readl_relaxed(tbu_base + DEBUG_TESTBUS_TBU);
+}
+
+u32 arm_smmu_debug_tcu_testbus_select(void __iomem *base,
+		void __iomem *tcu_base, enum tcu_testbus testbus,
+		bool write, u32 val)
+{
+	int offset;
+
+	if (testbus == CLK_TESTBUS) {
+		base = tcu_base;
+		offset = ARM_SMMU_TESTBUS_SEL_HLOS1_NS;
+	} else {
+		offset = ARM_SMMU_TESTBUS_SEL;
+	}
+
+	if (write) {
+		writel_relaxed(val, base + offset);
+		/* Make sure tcu select register is written to */
+		wmb();
+	} else {
+		return readl_relaxed(base + offset);
+	}
+
+	return 0;
+}
+
+u32 arm_smmu_debug_tcu_testbus_output(void __iomem *base)
+{
+	return readl_relaxed(base + ARM_SMMU_TESTBUS);
+}
+
+static void arm_smmu_debug_dump_tbu_qns4_testbus(struct device *dev,
+					void __iomem *tbu_base)
+{
+	int i;
+	u32 reg;
+
+	for (i = 0 ; i < TBU_QNS4_BRIDGE_SIZE; ++i) {
+		reg = arm_smmu_debug_tbu_testbus_select(tbu_base, READ, 0);
+		reg = (reg & ~TBU_QNS4_BRIDGE_MASK) | i << 0;
+		arm_smmu_debug_tbu_testbus_select(tbu_base, WRITE, reg);
+		dev_info(dev, "testbus_sel: 0x%lx Index: %d val: 0x%llx\n",
+			arm_smmu_debug_tbu_testbus_select(tbu_base,
+						READ, 0), i,
+			arm_smmu_debug_tbu_testbus_output(tbu_base));
+	}
+}
+
+static void arm_smmu_debug_program_tbu_testbus(void __iomem *tbu_base,
+					int tbu_testbus)
+{
+	u32 reg;
+
+	reg = arm_smmu_debug_tbu_testbus_select(tbu_base, READ, 0);
+	reg = (reg & ~TCU_PTW_QUEUE_MASK) | tbu_testbus;
+	arm_smmu_debug_tbu_testbus_select(tbu_base, WRITE, reg);
+}
+
+void arm_smmu_debug_dump_tbu_testbus(struct device *dev, void __iomem *tbu_base,
+			int tbu_testbus_sel)
+{
+	if (tbu_testbus_sel & TBU_CLK_GATE_CONTROLLER_TESTBUS_SEL) {
+		dev_info(dev, "Dumping TBU clk gate controller:\n");
+		arm_smmu_debug_program_tbu_testbus(tbu_base,
+				TBU_CLK_GATE_CONTROLLER_TESTBUS);
+		dev_info(dev, "testbus_sel: 0x%lx val: 0x%llx\n",
+			arm_smmu_debug_tbu_testbus_select(tbu_base,
+						READ, 0),
+			arm_smmu_debug_tbu_testbus_output(tbu_base));
+	}
+
+	if (tbu_testbus_sel & TBU_QNS4_A2Q_TESTBUS_SEL) {
+		dev_info(dev, "Dumping TBU qns4 a2q test bus:\n");
+		arm_smmu_debug_program_tbu_testbus(tbu_base,
+				TBU_QNS4_A2Q_TESTBUS);
+		arm_smmu_debug_dump_tbu_qns4_testbus(dev, tbu_base);
+	}
+
+	if (tbu_testbus_sel & TBU_QNS4_Q2A_TESTBUS_SEL) {
+		dev_info(dev, "Dumping qns4 q2a test bus:\n");
+		arm_smmu_debug_program_tbu_testbus(tbu_base,
+				TBU_QNS4_Q2A_TESTBUS);
+		arm_smmu_debug_dump_tbu_qns4_testbus(dev, tbu_base);
+	}
+
+	if (tbu_testbus_sel & TBU_MULTIMASTER_QCHANNEL_TESTBUS_SEL) {
+		dev_info(dev, "Dumping multi master qchannel:\n");
+		arm_smmu_debug_program_tbu_testbus(tbu_base,
+				TBU_MULTIMASTER_QCHANNEL_TESTBUS);
+		dev_info(dev, "testbus_sel: 0x%lx val: 0x%llx\n",
+			arm_smmu_debug_tbu_testbus_select(tbu_base,
+						READ, 0),
+			arm_smmu_debug_tbu_testbus_output(tbu_base));
+	}
+}
+
+static void arm_smmu_debug_program_tcu_testbus(struct device *dev,
+		void __iomem *base, void __iomem *tcu_base,
+		unsigned long mask, int start, int end, int shift,
+		bool print)
+{
+	u32 reg;
+	int i;
+
+	for (i = start; i < end; i++) {
+		reg = arm_smmu_debug_tcu_testbus_select(base, tcu_base,
+				PTW_AND_CACHE_TESTBUS, READ, 0);
+		reg &= mask;
+		reg |= i << shift;
+		arm_smmu_debug_tcu_testbus_select(base, tcu_base,
+				PTW_AND_CACHE_TESTBUS, WRITE, reg);
+		if (print)
+			dev_info(dev, "testbus_sel: 0x%lx Index: %d val: 0x%lx\n",
+				 arm_smmu_debug_tcu_testbus_select(base,
+				 tcu_base, PTW_AND_CACHE_TESTBUS, READ, 0),
+				 i, arm_smmu_debug_tcu_testbus_output(base));
+	}
+}
+
+void arm_smmu_debug_dump_tcu_testbus(struct device *dev, void __iomem *base,
+			void __iomem *tcu_base, int tcu_testbus_sel)
+{
+	int i;
+
+	if (tcu_testbus_sel & TCU_CACHE_TESTBUS_SEL) {
+		dev_info(dev, "Dumping TCU cache testbus:\n");
+		arm_smmu_debug_program_tcu_testbus(dev, base, tcu_base,
+				TCU_CACHE_TESTBUS, 0, 1, 0, false);
+		arm_smmu_debug_program_tcu_testbus(dev, base, tcu_base,
+						   ~TCU_PTW_QUEUE_MASK, 0,
+						   TCU_CACHE_LOOKUP_QUEUE_SIZE,
+						   2, true);
+	}
+
+	if (tcu_testbus_sel & TCU_PTW_TESTBUS_SEL) {
+		dev_info(dev, "Dumping TCU PTW test bus:\n");
+		arm_smmu_debug_program_tcu_testbus(dev, base, tcu_base, 1,
+				TCU_PTW_TESTBUS, TCU_PTW_TESTBUS + 1, 0, false);
+
+		arm_smmu_debug_program_tcu_testbus(dev, base, tcu_base,
+						~TCU_PTW_INTERNAL_STATES_MASK,
+						   0, TCU_PTW_INTERNAL_STATES,
+						   2, true);
+
+		for (i = TCU_PTW_QUEUE_START;
+			i < TCU_PTW_QUEUE_START + TCU_PTW_QUEUE_SIZE; ++i) {
+			arm_smmu_debug_program_tcu_testbus(dev, base, tcu_base,
+					~TCU_PTW_QUEUE_MASK, i, i + 1, 2, true);
+			arm_smmu_debug_program_tcu_testbus(dev, base, tcu_base,
+					~TCU_PTW_TESTBUS_SEL2_MASK, TCU_PTW_TESTBUS_SEL2,
+					TCU_PTW_TESTBUS_SEL2 + 1, 0, false);
+			dev_info(dev, "testbus_sel: 0x%lx Index: %d val: 0x%lx\n",
+				 arm_smmu_debug_tcu_testbus_select(base,
+				 tcu_base, PTW_AND_CACHE_TESTBUS, READ, 0),
+				 i, arm_smmu_debug_tcu_testbus_output(base));
+		}
+	}
+
+	/* program ARM_SMMU_TESTBUS_SEL_HLOS1_NS to select TCU clk testbus*/
+	arm_smmu_debug_tcu_testbus_select(base, tcu_base,
+			CLK_TESTBUS, WRITE, TCU_CLK_TESTBUS_SEL);
+	dev_info(dev, "Programming Tcu clk gate controller: testbus_sel: 0x%lx\n",
+		arm_smmu_debug_tcu_testbus_select(base, tcu_base,
+						CLK_TESTBUS, READ, 0));
+}

drivers/iommu/arm-smmu-debug.h

@@ -0,0 +1,99 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2019, The Linux Foundation. All rights reserved.
+ */
+
+#define ARM_SMMU_TESTBUS_SEL			0x25E4
+#define ARM_SMMU_TESTBUS			0x25E8
+#define ARM_SMMU_TESTBUS_SEL_HLOS1_NS		0x8
+#define DEBUG_TESTBUS_SEL_TBU			0x50
+#define DEBUG_TESTBUS_TBU			0x58
+
+#define TCU_PTW_TESTBUS				BIT(8)
+#define TCU_CACHE_TESTBUS			~TCU_PTW_TESTBUS
+#define TCU_PTW_TESTBUS_SEL			BIT(1)
+#define TCU_PTW_INTERNAL_STATES			3
+#define TCU_PTW_INTERNAL_STATES_MASK		GENMASK(7, 2)
+#define TCU_PTW_TESTBUS_SEL2			3
+#define TCU_PTW_TESTBUS_SEL2_MASK		GENMASK(1, 0)
+#define TCU_PTW_QUEUE_START			32
+#define TCU_PTW_QUEUE_SIZE			32
+#define TCU_PTW_QUEUE_MASK			GENMASK(7, 0)
+#define TCU_CACHE_TESTBUS_SEL			0x1
+#define TCU_CACHE_LOOKUP_QUEUE_SIZE		32
+#define TCU_CLK_TESTBUS_SEL			0x200
+
+
+#define TBU_CLK_GATE_CONTROLLER_TESTBUS_SEL	0x1
+#define TBU_QNS4_A2Q_TESTBUS_SEL		BIT(1)
+#define TBU_QNS4_Q2A_TESTBUS_SEL		BIT(2)
+#define TBU_MULTIMASTER_QCHANNEL_TESTBUS_SEL	BIT(3)
+#define TBU_CLK_GATE_CONTROLLER_TESTBUS		BIT(6)
+#define TBU_QNS4_A2Q_TESTBUS			BIT(7)
+#define TBU_QNS4_Q2A_TESTBUS			(BIT(5) | BIT(7))
+#define TBU_MULTIMASTER_QCHANNEL_TESTBUS	GENMASK(7, 6)
+#define TBU_QNS4_BRIDGE_SIZE			32
+#define TBU_QNS4_BRIDGE_MASK			GENMASK(4, 0)
+
+extern int tbu_testbus_sel;
+extern int tcu_testbus_sel;
+
+enum tcu_testbus {
+	PTW_AND_CACHE_TESTBUS,
+	CLK_TESTBUS,
+};
+
+enum testbus_sel {
+	SEL_TCU,
+	SEL_TBU,
+};
+
+enum testbus_ops {
+	TESTBUS_SELECT,
+	TESTBUS_OUTPUT,
+};
+
+#if IS_ENABLED(CONFIG_ARM_SMMU)
+
+u32 arm_smmu_debug_tbu_testbus_select(void __iomem *tbu_base,
+					bool write, u32 val);
+u32 arm_smmu_debug_tbu_testbus_output(void __iomem *tbu_base);
+u32 arm_smmu_debug_tcu_testbus_select(void __iomem *base,
+		void __iomem *tcu_base, enum tcu_testbus testbus,
+		bool write, u32 val);
+u32 arm_smmu_debug_tcu_testbus_output(void __iomem *base);
+void arm_smmu_debug_dump_tbu_testbus(struct device *dev, void __iomem *tbu_base,
+			int tbu_testbus_sel);
+void arm_smmu_debug_dump_tcu_testbus(struct device *dev, void __iomem *base,
+			void __iomem *tcu_base, int tcu_testbus_sel);
+
+#else
+static inline u32 arm_smmu_debug_tbu_testbus_select(void __iomem *tbu_base,
+				bool write, u32 val)
+{
+	return 0;
+}
+static inline u32 arm_smmu_debug_tbu_testbus_output(void __iomem *tbu_base)
+{
+	return 0;
+}
+u32 arm_smmu_debug_tcu_testbus_select(void __iomem *base,
+		void __iomem *tcu_base, enum tcu_testbus testbus,
+		bool write, u32 val)
+{
+}
+static inline u32 arm_smmu_debug_tcu_testbus_output(void __iomem *base)
+{
+	return 0;
+}
+static inline void arm_smmu_debug_dump_tbu_testbus(struct device *dev,
+			void __iomem *tbu_base, int tbu_testbus_sel)
+{
+}
+static inline void arm_smmu_debug_dump_tcu_testbus(struct device *dev,
+			void __iomem *base, void __iomem *tcu_base,
+			int tcu_testbus_sel)
+{
+}
+#endif
+

drivers/iommu/arm-smmu-qcom.c

@@ -14,6 +14,9 @@
 #include <linux/workqueue.h>
 
 #include "arm-smmu.h"
+#include "arm-smmu-debug.h"
+#include <linux/debugfs.h>
+#include <linux/uaccess.h>
 
 #define ARM_SMMU_IMPL_DEF1	6
 
@@ -421,6 +424,331 @@ static struct qsmmuv500_tbu_device *qsmmuv500_find_tbu(
  * snapshot capture feature.
  */
 static DEFINE_MUTEX(capture_reg_lock);
+static DEFINE_SPINLOCK(testbus_lock);
+
+#ifdef CONFIG_ARM_SMMU_TESTBUS_DEBUGFS
+static struct dentry *debugfs_testbus_dir;
+
+static ssize_t arm_smmu_debug_testbus_read(struct file *file,
+		char __user *ubuf, size_t count, loff_t *offset,
+		enum testbus_sel tbu, enum testbus_ops ops)
+
+{
+	char buf[100];
+	ssize_t retval;
+	size_t buflen;
+	int buf_len = sizeof(buf);
+
+	if (*offset)
+		return 0;
+
+	memset(buf, 0, buf_len);
+
+	if (tbu == SEL_TBU) {
+		struct qsmmuv500_tbu_device *tbu = file->private_data;
+		void __iomem *tbu_base = tbu->base;
+		long val;
+
+		arm_smmu_power_on(tbu->pwr);
+		if (ops == TESTBUS_SELECT)
+			val = arm_smmu_debug_tbu_testbus_select(tbu_base,
+							READ, 0);
+		else
+			val = arm_smmu_debug_tbu_testbus_output(tbu_base);
+		arm_smmu_power_off(tbu->smmu, tbu->pwr);
+
+		scnprintf(buf, buf_len, "0x%0x\n", val);
+	} else {
+
+		struct arm_smmu_device *smmu = file->private_data;
+		struct qsmmuv500_archdata *data = to_qsmmuv500_archdata(smmu);
+		void __iomem *base = arm_smmu_page(smmu, ARM_SMMU_GR0);
+		void __iomem *tcu_base = data->tcu_base;
+
+		arm_smmu_power_on(smmu->pwr);
+
+		if (ops == TESTBUS_SELECT) {
+			scnprintf(buf, buf_len, "TCU clk testbus sel: 0x%0x\n",
+				  arm_smmu_debug_tcu_testbus_select(base,
+					tcu_base, CLK_TESTBUS, READ, 0));
+			scnprintf(buf + strlen(buf), buf_len - strlen(buf),
+				  "TCU testbus sel : 0x%0x\n",
+				  arm_smmu_debug_tcu_testbus_select(base,
+					 tcu_base, PTW_AND_CACHE_TESTBUS,
+					 READ, 0));
+		} else {
+			scnprintf(buf, buf_len, "0x%0x\n",
+				  arm_smmu_debug_tcu_testbus_output(base));
+		}
+
+		arm_smmu_power_off(smmu, smmu->pwr);
+	}
+	buflen = min(count, strlen(buf));
+	if (copy_to_user(ubuf, buf, buflen)) {
+		pr_err_ratelimited("Couldn't copy_to_user\n");
+		retval = -EFAULT;
+	} else {
+		*offset = 1;
+		retval = buflen;
+	}
+
+	return retval;
+}
+
+static ssize_t arm_smmu_debug_tcu_testbus_sel_write(struct file *file,
+		const char __user *ubuf, size_t count, loff_t *offset)
+{
+	struct arm_smmu_device *smmu = file->private_data;
+	struct qsmmuv500_archdata *data = to_qsmmuv500_archdata(smmu);
+	void __iomem *tcu_base = data->tcu_base;
+	void __iomem *base = arm_smmu_page(smmu, ARM_SMMU_GR0);
+	char *comma;
+	char buf[100];
+	u64 sel, val;
+
+	if (count >= 100) {
+		pr_err_ratelimited("Value too large\n");
+		return -EINVAL;
+	}
+
+	memset(buf, 0, 100);
+
+	if (copy_from_user(buf, ubuf, count)) {
+		pr_err_ratelimited("Couldn't copy from user\n");
+		return -EFAULT;
+	}
+
+	comma = strnchr(buf, count, ',');
+	if (!comma)
+		goto invalid_format;
+
+	/* split up the words */
+	*comma = '\0';
+
+	if (kstrtou64(buf, 0, &sel))
+		goto invalid_format;
+
+	if (sel != 1 && sel != 2)
+		goto invalid_format;
+
+	if (kstrtou64(comma + 1, 0, &val))
+		goto invalid_format;
+
+	arm_smmu_power_on(smmu->pwr);
+
+	if (sel == 1)
+		arm_smmu_debug_tcu_testbus_select(base,
+				tcu_base, CLK_TESTBUS, WRITE, val);
+	else if (sel == 2)
+		arm_smmu_debug_tcu_testbus_select(base,
+				tcu_base, PTW_AND_CACHE_TESTBUS, WRITE, val);
+
+	arm_smmu_power_off(smmu, smmu->pwr);
+
+	return count;
+
+invalid_format:
+	pr_err_ratelimited("Invalid format. Expected: <1, testbus select> for tcu CLK testbus (or) <2, testbus select> for tcu PTW/CACHE testbuses\n");
+	return -EINVAL;
+}
+
+static ssize_t arm_smmu_debug_tcu_testbus_sel_read(struct file *file,
+		char __user *ubuf, size_t count, loff_t *offset)
+{
+	return arm_smmu_debug_testbus_read(file, ubuf,
+			count, offset, SEL_TCU, TESTBUS_SELECT);
+}
+
+static const struct file_operations arm_smmu_debug_tcu_testbus_sel_fops = {
+	.open	= simple_open,
+	.write	= arm_smmu_debug_tcu_testbus_sel_write,
+	.read	= arm_smmu_debug_tcu_testbus_sel_read,
+};
+
+static ssize_t arm_smmu_debug_tcu_testbus_read(struct file *file,
+		char __user *ubuf, size_t count, loff_t *offset)
+{
+	return arm_smmu_debug_testbus_read(file, ubuf,
+			count, offset, SEL_TCU, TESTBUS_OUTPUT);
+}
+
+static const struct file_operations arm_smmu_debug_tcu_testbus_fops = {
+	.open	= simple_open,
+	.read	= arm_smmu_debug_tcu_testbus_read,
+};
+
+static int qsmmuv500_tcu_testbus_init(struct arm_smmu_device *smmu)
+{
+	struct dentry *testbus_dir;
+
+	if (!iommu_debugfs_dir)
+		return 0;
+
+	if (!debugfs_testbus_dir) {
+		debugfs_testbus_dir = debugfs_create_dir("testbus",
+						       iommu_debugfs_dir);
+		if (IS_ERR(debugfs_testbus_dir)) {
+			pr_err_ratelimited("Couldn't create iommu/testbus debugfs directory\n");
+			return -ENODEV;
+		}
+	}
+
+	testbus_dir = debugfs_create_dir(dev_name(smmu->dev),
+				debugfs_testbus_dir);
+
+	if (IS_ERR(testbus_dir)) {
+		pr_err_ratelimited("Couldn't create iommu/testbus/%s debugfs directory\n",
+		       dev_name(smmu->dev));
+		goto err;
+	}
+
+	if (IS_ERR(debugfs_create_file("tcu_testbus_sel", 0400,
+					testbus_dir, smmu,
+					&arm_smmu_debug_tcu_testbus_sel_fops))) {
+		pr_err_ratelimited("Couldn't create iommu/testbus/%s/tcu_testbus_sel debugfs file\n",
+		       dev_name(smmu->dev));
+		goto err_rmdir;
+	}
+
+	if (IS_ERR(debugfs_create_file("tcu_testbus_output", 0400,
+					testbus_dir, smmu,
+					&arm_smmu_debug_tcu_testbus_fops))) {
+		pr_err_ratelimited("Couldn't create iommu/testbus/%s/tcu_testbus_output debugfs file\n",
+				   dev_name(smmu->dev));
+		goto err_rmdir;
+	}
+
+	return 0;
+err_rmdir:
+	debugfs_remove_recursive(testbus_dir);
+err:
+	return 0;
+}
+
+static ssize_t arm_smmu_debug_tbu_testbus_sel_write(struct file *file,
+		const char __user *ubuf, size_t count, loff_t *offset)
+{
+	struct qsmmuv500_tbu_device *tbu = file->private_data;
+	void __iomem *tbu_base = tbu->base;
+	u64 val;
+
+	if (kstrtoull_from_user(ubuf, count, 0, &val)) {
+		pr_err_ratelimited("Invalid format for tbu testbus select\n");
+		return -EINVAL;
+	}
+
+	arm_smmu_power_on(tbu->pwr);
+	arm_smmu_debug_tbu_testbus_select(tbu_base, WRITE, val);
+	arm_smmu_power_off(tbu->smmu, tbu->pwr);
+
+	return count;
+}
+
+static ssize_t arm_smmu_debug_tbu_testbus_sel_read(struct file *file,
+		char __user *ubuf, size_t count, loff_t *offset)
+{
+	return arm_smmu_debug_testbus_read(file, ubuf,
+			count, offset, SEL_TBU, TESTBUS_SELECT);
+}
+
+static const struct file_operations arm_smmu_debug_tbu_testbus_sel_fops = {
+	.open	= simple_open,
+	.write	= arm_smmu_debug_tbu_testbus_sel_write,
+	.read	= arm_smmu_debug_tbu_testbus_sel_read,
+};
+
+static ssize_t arm_smmu_debug_tbu_testbus_read(struct file *file,
+		char __user *ubuf, size_t count, loff_t *offset)
+{
+	return arm_smmu_debug_testbus_read(file, ubuf,
+			count, offset, SEL_TBU, TESTBUS_OUTPUT);
+}
+
+static const struct file_operations arm_smmu_debug_tbu_testbus_fops = {
+	.open	= simple_open,
+	.read	= arm_smmu_debug_tbu_testbus_read,
+};
+
+static int qsmmuv500_tbu_testbus_init(struct qsmmuv500_tbu_device *tbu)
+{
+	struct dentry *testbus_dir;
+
+	if (!iommu_debugfs_dir)
+		return 0;
+
+	if (!debugfs_testbus_dir) {
+		debugfs_testbus_dir = debugfs_create_dir("testbus",
+						       iommu_debugfs_dir);
+		if (IS_ERR(debugfs_testbus_dir)) {
+			pr_err_ratelimited("Couldn't create iommu/testbus debugfs directory\n");
+			return -ENODEV;
+		}
+	}
+
+	testbus_dir = debugfs_create_dir(dev_name(tbu->dev),
+				debugfs_testbus_dir);
+
+	if (IS_ERR(testbus_dir)) {
+		pr_err_ratelimited("Couldn't create iommu/testbus/%s debugfs directory\n",
+		       dev_name(tbu->dev));
+		goto err;
+	}
+
+	if (IS_ERR(debugfs_create_file("tbu_testbus_sel", 0400,
+					testbus_dir, tbu,
+					&arm_smmu_debug_tbu_testbus_sel_fops)))	{
+		pr_err_ratelimited("Couldn't create iommu/testbus/%s/tbu_testbus_sel debugfs file\n",
+		       dev_name(tbu->dev));
+		goto err_rmdir;
+	}
+
+	if (IS_ERR(debugfs_create_file("tbu_testbus_output", 0400,
+					testbus_dir, tbu,
+					&arm_smmu_debug_tbu_testbus_fops))) {
+		pr_err_ratelimited("Couldn't create iommu/testbus/%s/tbu_testbus_output debugfs file\n",
+		       dev_name(tbu->dev));
+		goto err_rmdir;
+	}
+
+	return 0;
+err_rmdir:
+	debugfs_remove_recursive(testbus_dir);
+err:
+	return 0;
+}
+#else
+static int qsmmuv500_tcu_testbus_init(struct arm_smmu_device *smmu)
+{
+	return 0;
+}
+
+static int qsmmuv500_tbu_testbus_init(struct qsmmuv500_tbu_device *tbu)
+{
+	return 0;
+}
+#endif
+
+static void arm_smmu_testbus_dump(struct arm_smmu_device *smmu, u16 sid)
+{
+	if (smmu->model == QCOM_SMMUV500 &&
+	    IS_ENABLED(CONFIG_ARM_SMMU_TESTBUS_DUMP)) {
+		struct qsmmuv500_archdata *data = to_qsmmuv500_archdata(smmu);
+		struct qsmmuv500_tbu_device *tbu;
+
+		tbu = qsmmuv500_find_tbu(smmu, sid);
+		spin_lock(&testbus_lock);
+		if (tbu)
+			arm_smmu_debug_dump_tbu_testbus(tbu->dev,
+							tbu->base,
+							tbu_testbus_sel);
+		else
+			arm_smmu_debug_dump_tcu_testbus(smmu->dev,
+							smmu->base,
+							data->tcu_base,
+							tcu_testbus_sel);
+		spin_unlock(&testbus_lock);
+	}
+}
 
 static void qsmmuv500_log_outstanding_transactions(struct work_struct *work)
 {
@@ -583,8 +911,14 @@ static void qsmmuv500_tlb_sync_timeout(struct arm_smmu_device *smmu)
 					tbu_sync_pending ?
 					"check pending transactions on TBU"
 					: "check for TBU power status");
+				arm_smmu_testbus_dump(smmu,
+						(u16)(tbu_id << TBUID_SHIFT));
 			}
 		}
+
+		/*dump TCU testbus*/
+		arm_smmu_testbus_dump(smmu, U16_MAX);
+
 	}
 
 	if (tcu_sync_pending) {
@@ -1064,6 +1398,8 @@ static int qsmmuv500_tbu_register(struct device *dev, void *cookie)
 	INIT_LIST_HEAD(&tbu->list);
 	tbu->smmu = &data->smmu;
 	list_add(&tbu->list, &data->tbus);
+
+	qsmmuv500_tbu_testbus_init(tbu);
 	return 0;
 }
 
@@ -1156,6 +1492,8 @@ struct arm_smmu_device *qsmmuv500_impl_init(struct arm_smmu_device *smmu)
 	data->smmu = *smmu;
 	data->smmu.impl = &qsmmuv500_impl;
 
+	qsmmuv500_tcu_testbus_init(&data->smmu);
+
 	ret = qsmmuv500_read_actlr_tbl(data);
 	if (ret)
 		return ERR_PTR(ret);

drivers/iommu/arm-smmu.c

@@ -110,6 +110,15 @@ struct arm_smmu_cb {
 #define ARM_SMMU_CB_VMID(smmu, cfg) ((u16)(smmu)->cavium_id_base + \
 							(cfg)->cbndx + 1)
 
+#define TCU_TESTBUS_SEL_ALL 0x3
+#define TBU_TESTBUS_SEL_ALL 0xf
+
+int tbu_testbus_sel = TBU_TESTBUS_SEL_ALL;
+int tcu_testbus_sel = TCU_TESTBUS_SEL_ALL;
+
+module_param_named(tcu_testbus_sel, tcu_testbus_sel, int, 0644);
+module_param_named(tbu_testbus_sel, tbu_testbus_sel, int, 0644);
+
 struct arm_smmu_pte_info {
 	void *virt_addr;
 	size_t size;