Debug stream debugfs

include/sound/sof/ipc4/header.h

@@ -650,6 +650,7 @@ struct sof_ipc4_notify_resource_data {
 #define SOF_IPC4_DEBUG_SLOT_DEBUG_LOG		0x474f4c00 /* byte 0: core ID */
 #define SOF_IPC4_DEBUG_SLOT_GDB_STUB		0x42444700
 #define SOF_IPC4_DEBUG_SLOT_TELEMETRY		0x4c455400
+#define SOF_IPC4_DEBUG_SLOT_DEBUG_STREAM	0x53523134
 #define SOF_IPC4_DEBUG_SLOT_BROKEN		0x44414544
 
 /**

sound/soc/sof/Makefile

@@ -12,7 +12,7 @@ snd-sof-$(CONFIG_SND_SOC_SOF_COMPRESS) += ipc3-compress.o
 endif
 ifneq ($(CONFIG_SND_SOC_SOF_IPC4),)
 snd-sof-y += ipc4.o ipc4-loader.o ipc4-topology.o ipc4-control.o ipc4-pcm.o\
-		ipc4-mtrace.o ipc4-telemetry.o
+		ipc4-mtrace.o ipc4-debug-slot-debugfs.o
 snd-sof-$(CONFIG_SND_SOC_SOF_COMPRESS) += ipc4-compress.o
 endif
 

sound/soc/sof/ipc4-debug-slot-debugfs.c

@@ -0,0 +1,113 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause)
+//
+// This file is provided under a dual BSD/GPLv2 license.  When using or
+// redistributing this file, you may do so under either license.
+//
+// Copyright(c) 2024-2025 Intel Corporation.
+//
+
+#include <linux/debugfs.h>
+#include <linux/io.h>
+#include <linux/pm_runtime.h>
+#include <sound/sof/debug.h>
+#include <sound/sof/ipc4/header.h>
+#include "sof-priv.h"
+#include "ops.h"
+#include "ipc4-priv.h"
+
+struct debug_slot_fs_ud {
+	struct snd_sof_dfsentry dfse;
+	u32 slot_type;
+	size_t data_offset;
+};
+
+static ssize_t sof_debug_slot_debugfs_entry_read(struct file *file, char __user *buffer,
+						 size_t count, loff_t *ppos)
+{
+	struct debug_slot_fs_ud *ud = file->private_data;
+	struct snd_sof_dfsentry *dfse = &ud->dfse;
+	struct snd_sof_dev *sdev = dfse->sdev;
+	size_t doffset = ud->data_offset;
+	u32 type = ud->slot_type;
+	loff_t pos = *ppos;
+	size_t exposed_size;
+	size_t size_ret;
+	u32 offset;
+	u8 *buf;
+
+	if (doffset >= SOF_IPC4_DEBUG_SLOT_SIZE)
+		return -EINVAL;
+
+	exposed_size = SOF_IPC4_DEBUG_SLOT_SIZE - doffset;
+
+	if (pos < 0)
+		return -EINVAL;
+	if (pos >= exposed_size || !count)
+		return 0;
+	if (count > exposed_size - pos)
+		count = exposed_size - pos;
+
+	offset = sof_ipc4_find_debug_slot_offset_by_type(sdev, type);
+	if (!offset)
+		return -EFAULT;
+
+	buf = kzalloc(exposed_size, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	sof_mailbox_read(sdev, offset + doffset, buf, exposed_size);
+	size_ret = copy_to_user(buffer, buf + pos, count);
+	kfree(buf);
+	if (size_ret)
+		return -EFAULT;
+
+	*ppos = pos + count;
+
+	return count;
+}
+
+static const struct file_operations sof_debug_stream_fops = {
+	.open = simple_open,
+	.read = sof_debug_slot_debugfs_entry_read,
+	.llseek = default_llseek,
+};
+
+void sof_ipc4_create_debug_slot_ro_debugfs_node(struct snd_sof_dev *sdev, u32 slot_type,
+					       size_t data_offset, const char *name)
+{
+	struct debug_slot_fs_ud *ud;
+	size_t exposed_size;
+
+	if (data_offset >= SOF_IPC4_DEBUG_SLOT_SIZE)
+		return;
+
+	exposed_size = SOF_IPC4_DEBUG_SLOT_SIZE - data_offset;
+
+	/*
+	 * Reject partial descriptor 15 if this interface must not cross the
+	 * end of page 0 into the next slot.
+	 */
+	if (slot_type == SOF_IPC4_DEBUG_SLOT_DEBUG_STREAM &&
+	    sof_ipc4_find_debug_slot_offset_by_type(sdev, slot_type) ==
+ 	    sdev->debug_box.offset + SOF_IPC4_DEBUG_PAGE0_SLOT_OFFSET)
+		return;
+
+	if (data_offset >= SOF_IPC4_DEBUG_SLOT_SIZE)
+		return;
+
+	ud = devm_kzalloc(sdev->dev, sizeof(*ud), GFP_KERNEL);
+	if (!ud)
+		return;
+
+	ud->dfse.type = SOF_DFSENTRY_TYPE_IOMEM;
+	ud->dfse.size = exposed_size;
+	ud->dfse.access_type = SOF_DEBUGFS_ACCESS_ALWAYS;
+	ud->dfse.sdev = sdev;
+
+	ud->slot_type = slot_type;
+	ud->data_offset = data_offset;
+
+	list_add(&ud->dfse.list, &sdev->dfsentry_list);
+
+	debugfs_create_file(name, 0444, sdev->debugfs_root, ud, &sof_debug_stream_fops);
+}

sound/soc/sof/ipc4-priv.h

@@ -180,4 +180,6 @@ static inline void sof_ipc4_compr_drain_done(struct snd_sof_dev *sdev,
 					     void *ipc_message) { }
 #endif
 
+void sof_ipc4_create_debug_slot_ro_debugfs_node(struct snd_sof_dev *sdev, u32 slot_type,
+						size_t data_offset, const char *name);
 #endif

sound/soc/sof/ipc4-telemetry.h

@@ -69,5 +69,4 @@ struct sof_ipc4_telemetry_slot_data {
 	u32 arch_data[];
 } __packed;
 
-void sof_ipc4_create_exception_debugfs_node(struct snd_sof_dev *sdev);
 #endif

sound/soc/sof/ipc4.c

@@ -16,7 +16,6 @@
 #include "ipc4-fw-reg.h"
 #include "ipc4-priv.h"
 #include "ipc4-topology.h"
-#include "ipc4-telemetry.h"
 #include "ops.h"
 
 static const struct sof_ipc4_fw_status {
@@ -720,7 +719,8 @@ size_t sof_ipc4_find_debug_slot_offset_by_type(struct snd_sof_dev *sdev,
 		slot_desc_type_offset += SOF_IPC4_DEBUG_DESCRIPTOR_SIZE;
 	}
 
-	dev_dbg(sdev->dev, "Slot type %#x is not available in debug window\n", slot_type);
+	dev_dbg_ratelimited(sdev->dev, "Slot type %#x is not available in debug window\n",
+			    slot_type);
 	return 0;
 }
 EXPORT_SYMBOL(sof_ipc4_find_debug_slot_offset_by_type);
@@ -741,7 +741,12 @@ static int ipc4_fw_ready(struct snd_sof_dev *sdev, struct sof_ipc4_msg *ipc4_msg
 		return 0;
 	}
 
-	sof_ipc4_create_exception_debugfs_node(sdev);
+	/* sizeof(u32) is for skipping the first separator magic number */
+	sof_ipc4_create_debug_slot_ro_debugfs_node(sdev, SOF_IPC4_DEBUG_SLOT_TELEMETRY,
+						   sizeof(u32), "exception");
+
+	sof_ipc4_create_debug_slot_ro_debugfs_node(sdev, SOF_IPC4_DEBUG_SLOT_DEBUG_STREAM,
+						   0, "debug_stream");
 
 	return sof_ipc4_init_msg_memory(sdev);
 }