new file mode 100644
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+// SPDX-License-Identifier: (GPL-2.0 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) 2018 Intel Corporation. All rights reserved.
+//
+// Author: Liam Girdwood <liam.r.girdwood@linux.intel.com>
+//
+// Generic debug routines used to export DSP MMIO and memories to userspace
+// for firmware debugging.
+//
+
+#include <linux/debugfs.h>
+#include <linux/io.h>
+#include <linux/pm_runtime.h>
+#include "sof-priv.h"
+#include "ops.h"
+
+static ssize_t sof_dfsentry_read(struct file *file, char __user *buffer,
+ size_t count, loff_t *ppos)
+{
+ struct snd_sof_dfsentry *dfse = file->private_data;
+ struct snd_sof_dev *sdev = dfse->sdev;
+ struct dentry *dfsentry = dfse->dfsentry;
+ int size;
+ u32 *buf;
+ loff_t pos = *ppos;
+ size_t size_ret;
+
+ size = dfse->size;
+
+ /* validate position & count */
+ if (pos < 0)
+ return -EINVAL;
+ if (pos >= size || !count)
+ return 0;
+ /* find the minimum. min() is not used since it adds sparse warnings */
+ if (count > size - pos)
+ count = size - pos;
+
+ /* intermediate buffer size must be u32 multiple */
+ size = round_up(count, 4);
+ buf = kzalloc(size, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ if (dfse->type == SOF_DFSENTRY_TYPE_IOMEM) {
+#if IS_ENABLED(CONFIG_SND_SOC_SOF_DEBUG_ENABLE_DEBUGFS_CACHE)
+ /*
+ * If the DSP is active: copy from IO.
+ * If the DSP is suspended:
+ * - Copy from IO if the memory is always accessible.
+ * - Otherwise, copy from cached buffer.
+ */
+ if (pm_runtime_active(sdev->dev) ||
+ dfse->access_type == SOF_DEBUGFS_ACCESS_ALWAYS) {
+ memcpy_fromio(buf, dfse->io_mem + pos, size);
+ } else {
+ dev_info(sdev->dev,
+ "Copying cached debugfs data\n");
+ memcpy(buf, dfse->cache_buf + pos, size);
+ }
+#else
+ /* if the DSP is in D3 */
+ if (!pm_runtime_active(sdev->dev) &&
+ dfse->access_type == SOF_DEBUGFS_ACCESS_D0_ONLY) {
+ dev_err(sdev->dev,
+ "error: debugfs entry %s cannot be read in DSP D3\n",
+ dfsentry->d_name.name);
+ return -EINVAL;
+ }
+
+ memcpy_fromio(buf, dfse->io_mem + pos, size);
+#endif
+ } else {
+ memcpy(buf, dfse->buf + pos, size);
+ }
+
+ /* copy to userspace */
+ size_ret = copy_to_user(buffer, buf, count);
+ kfree(buf);
+
+ /* update count & position if copy succeeded */
+ if (size_ret == count)
+ return -EFAULT;
+ count -= size_ret;
+ *ppos = pos + count;
+
+ return count;
+}
+
+static const struct file_operations sof_dfs_fops = {
+ .open = simple_open,
+ .read = sof_dfsentry_read,
+ .llseek = default_llseek,
+};
+
+/* create FS entry for debug files that can expose DSP memories, registers */
+int snd_sof_debugfs_io_item(struct snd_sof_dev *sdev,
+ void __iomem *base, size_t size,
+ const char *name,
+ enum sof_debugfs_access_type access_type)
+{
+ struct snd_sof_dfsentry *dfse;
+
+ if (!sdev)
+ return -EINVAL;
+
+ dfse = devm_kzalloc(sdev->dev, sizeof(*dfse), GFP_KERNEL);
+ if (!dfse)
+ return -ENOMEM;
+
+ dfse->type = SOF_DFSENTRY_TYPE_IOMEM;
+ dfse->io_mem = base;
+ dfse->size = size;
+ dfse->sdev = sdev;
+ dfse->access_type = access_type;
+
+#if IS_ENABLED(CONFIG_SND_SOC_SOF_DEBUG_ENABLE_DEBUGFS_CACHE)
+ /*
+ * allocate cache buffer that will be used to save the mem window
+ * contents prior to suspend
+ */
+ if (access_type == SOF_DEBUGFS_ACCESS_D0_ONLY) {
+ dfse->cache_buf = devm_kzalloc(sdev->dev, size, GFP_KERNEL);
+ if (!dfse->cache_buf)
+ return -ENOMEM;
+ }
+#endif
+
+ dfse->dfsentry = debugfs_create_file(name, 0444, sdev->debugfs_root,
+ dfse, &sof_dfs_fops);
+ if (!dfse->dfsentry) {
+ /* can't rely on debugfs, only log error and keep going */
+ dev_err(sdev->dev, "error: cannot create debugfs entry %s\n",
+ name);
+ } else {
+ /* add to dfsentry list */
+ list_add(&dfse->list, &sdev->dfsentry_list);
+
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(snd_sof_debugfs_io_item);
+
+/* create FS entry for debug files to expose kernel memory */
+int snd_sof_debugfs_buf_item(struct snd_sof_dev *sdev,
+ void *base, size_t size,
+ const char *name)
+{
+ struct snd_sof_dfsentry *dfse;
+
+ if (!sdev)
+ return -EINVAL;
+
+ dfse = devm_kzalloc(sdev->dev, sizeof(*dfse), GFP_KERNEL);
+ if (!dfse)
+ return -ENOMEM;
+
+ dfse->type = SOF_DFSENTRY_TYPE_BUF;
+ dfse->buf = base;
+ dfse->size = size;
+ dfse->sdev = sdev;
+
+ dfse->dfsentry = debugfs_create_file(name, 0444, sdev->debugfs_root,
+ dfse, &sof_dfs_fops);
+ if (!dfse->dfsentry) {
+ /* can't rely on debugfs, only log error and keep going */
+ dev_err(sdev->dev, "error: cannot create debugfs entry %s\n",
+ name);
+ } else {
+ /* add to dfsentry list */
+ list_add(&dfse->list, &sdev->dfsentry_list);
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(snd_sof_debugfs_buf_item);
+
+int snd_sof_dbg_init(struct snd_sof_dev *sdev)
+{
+ const struct snd_sof_dsp_ops *ops = sof_ops(sdev);
+ const struct snd_sof_debugfs_map *map;
+ int i;
+ int err;
+
+ /* use "sof" as top level debugFS dir */
+ sdev->debugfs_root = debugfs_create_dir("sof", NULL);
+ if (IS_ERR_OR_NULL(sdev->debugfs_root)) {
+ dev_err(sdev->dev, "error: failed to create debugfs directory\n");
+ return 0;
+ }
+
+ /* init dfsentry list */
+ INIT_LIST_HEAD(&sdev->dfsentry_list);
+
+ /* create debugFS files for platform specific MMIO/DSP memories */
+ for (i = 0; i < ops->debug_map_count; i++) {
+ map = &ops->debug_map[i];
+
+ err = snd_sof_debugfs_io_item(sdev, sdev->bar[map->bar] +
+ map->offset, map->size,
+ map->name, map->access_type);
+ /* errors are only due to memory allocation, not debugfs */
+ if (err < 0)
+ return err;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(snd_sof_dbg_init);
+
+void snd_sof_free_debug(struct snd_sof_dev *sdev)
+{
+ debugfs_remove_recursive(sdev->debugfs_root);
+}
+EXPORT_SYMBOL_GPL(snd_sof_free_debug);