accel/amdxdna: Add iommu_bypass debugfs for aie4 only

drivers/accel/amdxdna/Kbuild

@@ -60,3 +60,4 @@ amdxdna-$(CONFIG_PCI_IOV) += \
 
 amdxdna-$(CONFIG_DEBUG_FS) += \
 	amdxdna_debugfs.o \
+	aie4_debugfs.o \

drivers/accel/amdxdna/aie4_debugfs.c

@@ -0,0 +1,124 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2026, Advanced Micro Devices, Inc.
+ */
+
+#include <drm/drm_file.h>
+#include <linux/debugfs.h>
+#include <linux/pm_runtime.h>
+#include <linux/seq_file.h>
+#include <linux/string.h>
+#include <linux/uaccess.h>
+
+#include "amdxdna_cbuf.h"
+#include "amdxdna_debugfs.h"
+#include "aie4_pci.h"
+#include "aie4_msg_priv.h"
+#include "amdxdna_mailbox.h"
+#include "amdxdna_mailbox_helper.h"
+
+#define _DBGFS_FOPS(_open, _release, _write) \
+{ \
+	.owner = THIS_MODULE, \
+	.open = _open, \
+	.read = seq_read, \
+	.llseek = seq_lseek, \
+	.release = _release, \
+	.write = _write, \
+}
+
+#define AMDXDNA_DBGFS_FOPS(_name, _show, _write) \
+	static int amdxdna_dbgfs_##_name##_open(struct inode *inode, struct file *file) \
+	{ \
+		return single_open(file, _show, inode->i_private); \
+	} \
+	static int amdxdna_dbgfs_##_name##_release(struct inode *inode, struct file *file) \
+	{ \
+		return single_release(inode, file); \
+	} \
+	static const struct file_operations amdxdna_fops_##_name = \
+		_DBGFS_FOPS(amdxdna_dbgfs_##_name##_open, amdxdna_dbgfs_##_name##_release, _write)
+
+#define AMDXDNA_DBGFS_FILE(_name, _mode) { #_name, &amdxdna_fops_##_name, _mode }
+
+#define file_to_xdna(file) (((struct seq_file *)(file)->private_data)->private)
+
+static int amdxdna_iommu_bypass_show(struct seq_file *m, void *unused)
+{
+	return 0;
+}
+
+static ssize_t amdxdna_iommu_bypass_write(struct file *file, const char __user *buf,
+					  size_t count, loff_t *ppos)
+{
+	DECLARE_AIE_MSG(aie4_msg_echo, AIE4_MSG_OP_ECHO);
+	struct amdxdna_dev *xdna = file_to_xdna(file);
+	struct amdxdna_dev_hdl *ndev = xdna->dev_handle;
+	char kbuf[32];
+	u8 val;
+	int ret;
+
+	if (count == 0 || count >= sizeof(kbuf))
+		return -EINVAL;
+
+	if (copy_from_user(kbuf, buf, count))
+		return -EFAULT;
+	kbuf[count] = '\0';
+	strim(kbuf);
+
+	XDNA_DBG(xdna, "Trying to set iommu_bypass mode to %s", kbuf);
+
+	ret = kstrtou8(kbuf, 0, &val);
+	if (ret)
+		return ret;
+
+	if (!val)
+		return count;
+
+	XDNA_DBG(xdna, "Setting iommu_bypass mode to %d", val);
+
+#define MAKE_MAGIC(a, b, c, d)  ((u32)((a) << 24 | (b) << 16 | (c) << 8 | (d)))
+	req.val1 = MAKE_MAGIC('B', 'Y', 'P', 'A');
+	req.val2 = MAKE_MAGIC('M', 'A', 'G', 'C');
+
+	guard(mutex)(&xdna->dev_lock);
+	ret = aie_send_mgmt_msg_wait(&ndev->aie, &msg);
+	if (ret)
+		XDNA_ERR(xdna, "echo failed: %d", ret);
+
+	if (req.val1 == resp.val1 &&
+	    req.val2 == resp.val2)
+		XDNA_INFO(xdna, "echo finished, response correct value.");
+	else
+		XDNA_WARN(xdna, "echo finished, expect: 0x%x,0x%x, got: 0x%x,0x%x",
+			  req.val1, req.val1, resp.val1, resp.val2);
+
+	return count;
+}
+
+/*
+ * Input/output format: <carveout_size>@<carveout_address>
+ */
+AMDXDNA_DBGFS_FOPS(iommu_bypass, amdxdna_iommu_bypass_show, amdxdna_iommu_bypass_write);
+
+static const struct {
+	const char *name;
+	const struct file_operations *fops;
+	umode_t mode;
+} aie4_dbgfs_files[] = {
+	AMDXDNA_DBGFS_FILE(iommu_bypass, 0200),
+};
+
+void aie4_debugfs_init(struct amdxdna_dev *xdna)
+{
+	struct drm_minor *minor = xdna->ddev.accel;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(aie4_dbgfs_files); i++) {
+		debugfs_create_file(aie4_dbgfs_files[i].name,
+				    aie4_dbgfs_files[i].mode,
+				    minor->debugfs_root,
+				    xdna,
+				    aie4_dbgfs_files[i].fops);
+	}
+}

drivers/accel/amdxdna/aie4_msg_priv.h

@@ -11,6 +11,7 @@
 #include <linux/types.h>
 
 enum aie4_msg_opcode {
+	AIE4_MSG_OP_ECHO                             = 0x10001,
 	AIE4_MSG_OP_SUSPEND                          = 0x10003,
 	AIE4_MSG_OP_ATTACH_WORK_BUFFER               = 0x1000D,
 	AIE4_MSG_OP_AIE_COREDUMP                     = 0x30010,
@@ -32,6 +33,17 @@ enum aie4_msg_status {
 	MAX_AIE4_MSG_STATUS_CODE = 0x4,
 };
 
+struct aie4_msg_echo_req {
+	__u32 val1;
+	__u32 val2;
+} __packed;
+
+struct aie4_msg_echo_resp {
+	enum aie4_msg_status status;
+	__u32 val1;
+	__u32 val2;
+} __packed;
+
 struct aie4_msg_suspend_req {
 	__u32 rsvd;
 } __packed;

drivers/accel/amdxdna/aie4_pci.c

@@ -773,6 +773,7 @@ const struct amdxdna_dev_ops aie4_pf_ops = {
 	.init			= aie4_pf_init,
 	.fini			= aie4_pf_fini,
 	.sriov_configure        = aie4_sriov_configure,
+	.debugfs		= aie4_debugfs_init,
 };
 
 const struct amdxdna_dev_ops aie4_vf_ops = {
@@ -797,4 +798,5 @@ const struct amdxdna_dev_ops aie4_classic_ops = {
 	.get_aie_info		= aie4_get_info,
 	.get_array		= aie4_get_array,
 	.get_coredump		= aie4_get_aie_coredump,
+	.debugfs		= aie4_debugfs_init,
 };

drivers/accel/amdxdna/aie4_pci.h

@@ -80,6 +80,9 @@ static inline int aie4_sriov_stop(struct amdxdna_dev_hdl *ndev)
 }
 #endif
 
+/* aie4_debugfs.c */
+void aie4_debugfs_init(struct amdxdna_dev *xdna);
+
 enum aie4_fw_feature {
 	AIE4_GET_COREDUMP,
 	AIE4_FEATURE_MAX

drivers/accel/amdxdna/amdxdna_debugfs.c

@@ -126,4 +126,7 @@ void amdxdna_debugfs_init(struct amdxdna_dev *xdna)
 				    xdna,
 				    amdxdna_dbgfs_files[i].fops);
 	}
+
+	if (xdna->dev_info->ops->debugfs)
+		xdna->dev_info->ops->debugfs(xdna);
 }

drivers/accel/amdxdna/amdxdna_pci_drv.c

@@ -435,6 +435,7 @@ static int amdxdna_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	}
 
 	amdxdna_debugfs_init(xdna);
+
 	return 0;
 
 failed_sysfs_fini:

drivers/accel/amdxdna/amdxdna_pci_drv.h

@@ -80,6 +80,7 @@ struct amdxdna_dev_ops {
 			    struct amdxdna_hwctx *hwctx, u32 num_bufs);
 	int (*get_dev_revision)(struct amdxdna_dev *xdna, u32 *rev);
 	int (*hwctx_heap_expand)(struct amdxdna_hwctx *hwctx);
+	void (*debugfs)(struct amdxdna_dev *xdna);
 };
 
 struct amdxdna_fw_feature_tbl {