Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

6 files changed, 699 insertions, 0 deletions

diff --git a/sound/ac97/Kconfig b/sound/ac97/Kconfig
new file mode 100644
index 000000000..f0e31f2bb
--- /dev/null
+++ b/sound/ac97/Kconfig
@@ -0,0 +1,19 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# AC97 configuration
+#
+
+
+config AC97_BUS_NEW
+	tristate
+	help
+	  This is the new AC97 bus type, successor of AC97_BUS. The ported
+	  drivers which benefit from the AC97 automatic probing should "select"
+	  this instead of the AC97_BUS.
+	  Say Y here if you want to have AC97 devices, which are sound oriented
+	  devices around an AC-Link.
+
+config AC97_BUS_COMPAT
+	bool
+	depends on AC97_BUS_NEW
+	depends on !AC97_BUS
diff --git a/sound/ac97/Makefile b/sound/ac97/Makefile
new file mode 100644
index 000000000..f5efa1ad7
--- /dev/null
+++ b/sound/ac97/Makefile
@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# make for AC97 bus drivers
+#
+
+obj-$(CONFIG_AC97_BUS_NEW)	+= ac97.o
+
+ac97-y				+= bus.o codec.o
+ac97-$(CONFIG_AC97_BUS_COMPAT)	+= snd_ac97_compat.o
diff --git a/sound/ac97/ac97_core.h b/sound/ac97/ac97_core.h
new file mode 100644
index 000000000..5a9677c3d
--- /dev/null
+++ b/sound/ac97/ac97_core.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2016 Robert Jarzmik <robert.jarzmik@free.fr>
+ */
+
+unsigned int snd_ac97_bus_scan_one(struct ac97_controller *adrv,
+				   unsigned int codec_num);
+
+static inline bool ac97_ids_match(unsigned int id1, unsigned int id2,
+				  unsigned int mask)
+{
+	return (id1 & mask) == (id2 & mask);
+}
diff --git a/sound/ac97/bus.c b/sound/ac97/bus.c
new file mode 100644
index 000000000..a4d230a19
--- /dev/null
+++ b/sound/ac97/bus.c
@@ -0,0 +1,526 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2016 Robert Jarzmik <robert.jarzmik@free.fr>
+ */
+
+#include <linux/module.h>
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/idr.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/pm.h>
+#include <linux/pm_runtime.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <sound/ac97_codec.h>
+#include <sound/ac97/codec.h>
+#include <sound/ac97/controller.h>
+#include <sound/ac97/regs.h>
+
+#include "ac97_core.h"
+
+/*
+ * Protects ac97_controllers and each ac97_controller structure.
+ */
+static DEFINE_MUTEX(ac97_controllers_mutex);
+static DEFINE_IDR(ac97_adapter_idr);
+static LIST_HEAD(ac97_controllers);
+
+static inline struct ac97_controller*
+to_ac97_controller(struct device *ac97_adapter)
+{
+	return container_of(ac97_adapter, struct ac97_controller, adap);
+}
+
+static int ac97_unbound_ctrl_write(struct ac97_controller *adrv, int slot,
+		     unsigned short reg, unsigned short val)
+{
+	return -ENODEV;
+}
+
+static int ac97_unbound_ctrl_read(struct ac97_controller *adrv, int slot,
+				  unsigned short reg)
+{
+	return -ENODEV;
+}
+
+static const struct ac97_controller_ops ac97_unbound_ctrl_ops = {
+	.write = ac97_unbound_ctrl_write,
+	.read = ac97_unbound_ctrl_read,
+};
+
+static struct ac97_controller ac97_unbound_ctrl = {
+	.ops = &ac97_unbound_ctrl_ops,
+};
+
+static struct ac97_codec_device *
+ac97_codec_find(struct ac97_controller *ac97_ctrl, unsigned int codec_num)
+{
+	if (codec_num >= AC97_BUS_MAX_CODECS)
+		return ERR_PTR(-EINVAL);
+
+	return ac97_ctrl->codecs[codec_num];
+}
+
+static struct device_node *
+ac97_of_get_child_device(struct ac97_controller *ac97_ctrl, int idx,
+			 unsigned int vendor_id)
+{
+	struct device_node *node;
+	u32 reg;
+	char compat[] = "ac97,0000,0000";
+
+	snprintf(compat, sizeof(compat), "ac97,%04x,%04x",
+		 vendor_id >> 16, vendor_id & 0xffff);
+
+	for_each_child_of_node(ac97_ctrl->parent->of_node, node) {
+		if ((idx != of_property_read_u32(node, "reg", &reg)) ||
+		    !of_device_is_compatible(node, compat))
+			continue;
+		return node;
+	}
+
+	return NULL;
+}
+
+static void ac97_codec_release(struct device *dev)
+{
+	struct ac97_codec_device *adev;
+	struct ac97_controller *ac97_ctrl;
+
+	adev = to_ac97_device(dev);
+	ac97_ctrl = adev->ac97_ctrl;
+	ac97_ctrl->codecs[adev->num] = NULL;
+	of_node_put(dev->of_node);
+	kfree(adev);
+}
+
+static int ac97_codec_add(struct ac97_controller *ac97_ctrl, int idx,
+		   unsigned int vendor_id)
+{
+	struct ac97_codec_device *codec;
+	int ret;
+
+	codec = kzalloc_obj(*codec);
+	if (!codec)
+		return -ENOMEM;
+	ac97_ctrl->codecs[idx] = codec;
+	codec->vendor_id = vendor_id;
+	codec->dev.release = ac97_codec_release;
+	codec->dev.bus = &ac97_bus_type;
+	codec->dev.parent = &ac97_ctrl->adap;
+	codec->num = idx;
+	codec->ac97_ctrl = ac97_ctrl;
+
+	device_initialize(&codec->dev);
+	dev_set_name(&codec->dev, "%s:%u", dev_name(ac97_ctrl->parent), idx);
+	codec->dev.of_node = ac97_of_get_child_device(ac97_ctrl, idx,
+						      vendor_id);
+
+	ret = device_add(&codec->dev);
+	if (ret) {
+		put_device(&codec->dev);
+		return ret;
+	}
+
+	return 0;
+}
+
+unsigned int snd_ac97_bus_scan_one(struct ac97_controller *adrv,
+				   unsigned int codec_num)
+{
+	unsigned short vid1, vid2;
+	int ret;
+
+	ret = adrv->ops->read(adrv, codec_num, AC97_VENDOR_ID1);
+	vid1 = (ret & 0xffff);
+	if (ret < 0)
+		return 0;
+
+	ret = adrv->ops->read(adrv, codec_num, AC97_VENDOR_ID2);
+	vid2 = (ret & 0xffff);
+	if (ret < 0)
+		return 0;
+
+	dev_dbg(&adrv->adap, "%s(codec_num=%u): vendor_id=0x%08x\n",
+		__func__, codec_num, AC97_ID(vid1, vid2));
+	return AC97_ID(vid1, vid2);
+}
+
+static int ac97_bus_scan(struct ac97_controller *ac97_ctrl)
+{
+	int ret, i;
+	unsigned int vendor_id;
+
+	for (i = 0; i < AC97_BUS_MAX_CODECS; i++) {
+		if (ac97_codec_find(ac97_ctrl, i))
+			continue;
+		if (!(ac97_ctrl->slots_available & BIT(i)))
+			continue;
+		vendor_id = snd_ac97_bus_scan_one(ac97_ctrl, i);
+		if (!vendor_id)
+			continue;
+
+		ret = ac97_codec_add(ac97_ctrl, i, vendor_id);
+		if (ret < 0)
+			return ret;
+	}
+	return 0;
+}
+
+static int ac97_bus_reset(struct ac97_controller *ac97_ctrl)
+{
+	ac97_ctrl->ops->reset(ac97_ctrl);
+
+	return 0;
+}
+
+/**
+ * snd_ac97_codec_driver_register - register an AC97 codec driver
+ * @drv: AC97 driver codec to register
+ *
+ * Register an AC97 codec driver to the ac97 bus driver, aka. the AC97 digital
+ * controller.
+ *
+ * Returns 0 on success or error code
+ */
+int snd_ac97_codec_driver_register(struct ac97_codec_driver *drv)
+{
+	drv->driver.bus = &ac97_bus_type;
+	return driver_register(&drv->driver);
+}
+EXPORT_SYMBOL_GPL(snd_ac97_codec_driver_register);
+
+/**
+ * snd_ac97_codec_driver_unregister - unregister an AC97 codec driver
+ * @drv: AC97 codec driver to unregister
+ *
+ * Unregister a previously registered ac97 codec driver.
+ */
+void snd_ac97_codec_driver_unregister(struct ac97_codec_driver *drv)
+{
+	driver_unregister(&drv->driver);
+}
+EXPORT_SYMBOL_GPL(snd_ac97_codec_driver_unregister);
+
+static void ac97_ctrl_codecs_unregister(struct ac97_controller *ac97_ctrl)
+{
+	int i;
+
+	for (i = 0; i < AC97_BUS_MAX_CODECS; i++)
+		if (ac97_ctrl->codecs[i]) {
+			ac97_ctrl->codecs[i]->ac97_ctrl = &ac97_unbound_ctrl;
+			device_unregister(&ac97_ctrl->codecs[i]->dev);
+		}
+}
+
+static ssize_t cold_reset_store(struct device *dev,
+				struct device_attribute *attr, const char *buf,
+				size_t len)
+{
+	struct ac97_controller *ac97_ctrl;
+
+	guard(mutex)(&ac97_controllers_mutex);
+	ac97_ctrl = to_ac97_controller(dev);
+	ac97_ctrl->ops->reset(ac97_ctrl);
+	return len;
+}
+static DEVICE_ATTR_WO(cold_reset);
+
+static ssize_t warm_reset_store(struct device *dev,
+				struct device_attribute *attr, const char *buf,
+				size_t len)
+{
+	struct ac97_controller *ac97_ctrl;
+
+	if (!dev)
+		return -ENODEV;
+
+	guard(mutex)(&ac97_controllers_mutex);
+	ac97_ctrl = to_ac97_controller(dev);
+	ac97_ctrl->ops->warm_reset(ac97_ctrl);
+	return len;
+}
+static DEVICE_ATTR_WO(warm_reset);
+
+static struct attribute *ac97_controller_device_attrs[] = {
+	&dev_attr_cold_reset.attr,
+	&dev_attr_warm_reset.attr,
+	NULL
+};
+
+static const struct attribute_group ac97_adapter_attr_group = {
+	.name	= "ac97_operations",
+	.attrs	= ac97_controller_device_attrs,
+};
+
+static const struct attribute_group *ac97_adapter_groups[] = {
+	&ac97_adapter_attr_group,
+	NULL,
+};
+
+static void ac97_del_adapter(struct ac97_controller *ac97_ctrl)
+{
+	scoped_guard(mutex, &ac97_controllers_mutex) {
+		ac97_ctrl_codecs_unregister(ac97_ctrl);
+		list_del(&ac97_ctrl->controllers);
+	}
+
+	device_unregister(&ac97_ctrl->adap);
+}
+
+static void ac97_adapter_release(struct device *dev)
+{
+	struct ac97_controller *ac97_ctrl;
+
+	ac97_ctrl = to_ac97_controller(dev);
+	idr_remove(&ac97_adapter_idr, ac97_ctrl->nr);
+	dev_dbg(&ac97_ctrl->adap, "adapter unregistered by %s\n",
+		dev_name(ac97_ctrl->parent));
+	kfree(ac97_ctrl);
+}
+
+static const struct device_type ac97_adapter_type = {
+	.groups		= ac97_adapter_groups,
+	.release	= ac97_adapter_release,
+};
+
+static int ac97_add_adapter(struct ac97_controller *ac97_ctrl)
+{
+	int ret;
+
+	guard(mutex)(&ac97_controllers_mutex);
+	ret = idr_alloc(&ac97_adapter_idr, ac97_ctrl, 0, 0, GFP_KERNEL);
+	ac97_ctrl->nr = ret;
+	if (ret >= 0) {
+		dev_set_name(&ac97_ctrl->adap, "ac97-%d", ret);
+		ac97_ctrl->adap.type = &ac97_adapter_type;
+		ac97_ctrl->adap.parent = ac97_ctrl->parent;
+		ret = device_register(&ac97_ctrl->adap);
+		if (ret)
+			put_device(&ac97_ctrl->adap);
+	} else
+		kfree(ac97_ctrl);
+
+	if (!ret) {
+		list_add(&ac97_ctrl->controllers, &ac97_controllers);
+		dev_dbg(&ac97_ctrl->adap, "adapter registered by %s\n",
+			dev_name(ac97_ctrl->parent));
+	}
+	return ret;
+}
+
+/**
+ * snd_ac97_controller_register - register an ac97 controller
+ * @ops: the ac97 bus operations
+ * @dev: the device providing the ac97 DC function
+ * @slots_available: mask of the ac97 codecs that can be scanned and probed
+ *                   bit0 => codec 0, bit1 => codec 1 ... bit 3 => codec 3
+ *
+ * Register a digital controller which can control up to 4 ac97 codecs. This is
+ * the controller side of the AC97 AC-link, while the slave side are the codecs.
+ *
+ * Returns a valid controller upon success, negative pointer value upon error
+ */
+struct ac97_controller *snd_ac97_controller_register(
+	const struct ac97_controller_ops *ops, struct device *dev,
+	unsigned short slots_available)
+{
+	struct ac97_controller *ac97_ctrl;
+	int ret;
+
+	ac97_ctrl = kzalloc_obj(*ac97_ctrl);
+	if (!ac97_ctrl)
+		return ERR_PTR(-ENOMEM);
+
+	ac97_ctrl->ops = ops;
+	ac97_ctrl->slots_available = slots_available;
+	ac97_ctrl->parent = dev;
+	ret = ac97_add_adapter(ac97_ctrl);
+
+	if (ret)
+		return ERR_PTR(ret);
+	ac97_bus_reset(ac97_ctrl);
+	ac97_bus_scan(ac97_ctrl);
+
+	return ac97_ctrl;
+}
+EXPORT_SYMBOL_GPL(snd_ac97_controller_register);
+
+/**
+ * snd_ac97_controller_unregister - unregister an ac97 controller
+ * @ac97_ctrl: the device previously provided to ac97_controller_register()
+ *
+ */
+void snd_ac97_controller_unregister(struct ac97_controller *ac97_ctrl)
+{
+	ac97_del_adapter(ac97_ctrl);
+}
+EXPORT_SYMBOL_GPL(snd_ac97_controller_unregister);
+
+static int ac97_pm_runtime_suspend(struct device *dev)
+{
+	struct ac97_codec_device *codec = to_ac97_device(dev);
+	int ret = pm_generic_runtime_suspend(dev);
+
+	if (ret == 0 && dev->driver) {
+		if (pm_runtime_is_irq_safe(dev))
+			clk_disable(codec->clk);
+		else
+			clk_disable_unprepare(codec->clk);
+	}
+
+	return ret;
+}
+
+static int ac97_pm_runtime_resume(struct device *dev)
+{
+	struct ac97_codec_device *codec = to_ac97_device(dev);
+	int ret;
+
+	if (dev->driver) {
+		if (pm_runtime_is_irq_safe(dev))
+			ret = clk_enable(codec->clk);
+		else
+			ret = clk_prepare_enable(codec->clk);
+		if (ret)
+			return ret;
+	}
+
+	return pm_generic_runtime_resume(dev);
+}
+
+static const struct dev_pm_ops ac97_pm = {
+	.suspend	= pm_generic_suspend,
+	.resume		= pm_generic_resume,
+	.freeze		= pm_generic_freeze,
+	.thaw		= pm_generic_thaw,
+	.poweroff	= pm_generic_poweroff,
+	.restore	= pm_generic_restore,
+	RUNTIME_PM_OPS(ac97_pm_runtime_suspend, ac97_pm_runtime_resume, NULL)
+};
+
+static int ac97_get_enable_clk(struct ac97_codec_device *adev)
+{
+	int ret;
+
+	adev->clk = clk_get(&adev->dev, "ac97_clk");
+	if (IS_ERR(adev->clk))
+		return PTR_ERR(adev->clk);
+
+	ret = clk_prepare_enable(adev->clk);
+	if (ret)
+		clk_put(adev->clk);
+
+	return ret;
+}
+
+static void ac97_put_disable_clk(struct ac97_codec_device *adev)
+{
+	clk_disable_unprepare(adev->clk);
+	clk_put(adev->clk);
+}
+
+static ssize_t vendor_id_show(struct device *dev,
+			      struct device_attribute *attr, char *buf)
+{
+	struct ac97_codec_device *codec = to_ac97_device(dev);
+
+	return sysfs_emit(buf, "%08x", codec->vendor_id);
+}
+static DEVICE_ATTR_RO(vendor_id);
+
+static struct attribute *ac97_dev_attrs[] = {
+	&dev_attr_vendor_id.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(ac97_dev);
+
+static int ac97_bus_match(struct device *dev, const struct device_driver *drv)
+{
+	struct ac97_codec_device *adev = to_ac97_device(dev);
+	const struct ac97_codec_driver *adrv = to_ac97_driver(drv);
+	const struct ac97_id *id = adrv->id_table;
+	int i = 0;
+
+	if (adev->vendor_id == 0x0 || adev->vendor_id == 0xffffffff)
+		return false;
+
+	do {
+		if (ac97_ids_match(id[i].id, adev->vendor_id, id[i].mask))
+			return true;
+	} while (id[i++].id);
+
+	return false;
+}
+
+static int ac97_bus_probe(struct device *dev)
+{
+	struct ac97_codec_device *adev = to_ac97_device(dev);
+	struct ac97_codec_driver *adrv = to_ac97_driver(dev->driver);
+	int ret;
+
+	ret = ac97_get_enable_clk(adev);
+	if (ret)
+		return ret;
+
+	pm_runtime_get_noresume(dev);
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+
+	ret = adrv->probe(adev);
+	if (ret == 0)
+		return 0;
+
+	pm_runtime_disable(dev);
+	pm_runtime_set_suspended(dev);
+	pm_runtime_put_noidle(dev);
+	ac97_put_disable_clk(adev);
+
+	return ret;
+}
+
+static void ac97_bus_remove(struct device *dev)
+{
+	struct ac97_codec_device *adev = to_ac97_device(dev);
+	struct ac97_codec_driver *adrv = to_ac97_driver(dev->driver);
+	int ret;
+
+	ret = pm_runtime_resume_and_get(dev);
+	if (ret < 0)
+		return;
+
+	adrv->remove(adev);
+	pm_runtime_put_noidle(dev);
+	ac97_put_disable_clk(adev);
+
+	pm_runtime_disable(dev);
+}
+
+const struct bus_type ac97_bus_type = {
+	.name		= "ac97bus",
+	.dev_groups	= ac97_dev_groups,
+	.match		= ac97_bus_match,
+	.pm		= pm_ptr(&ac97_pm),
+	.probe		= ac97_bus_probe,
+	.remove		= ac97_bus_remove,
+};
+
+static int __init ac97_bus_init(void)
+{
+	return bus_register(&ac97_bus_type);
+}
+subsys_initcall(ac97_bus_init);
+
+static void __exit ac97_bus_exit(void)
+{
+	bus_unregister(&ac97_bus_type);
+}
+module_exit(ac97_bus_exit);
+
+MODULE_DESCRIPTION("AC97 bus interface");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Robert Jarzmik <robert.jarzmik@free.fr>");
diff --git a/sound/ac97/codec.c b/sound/ac97/codec.c
new file mode 100644
index 000000000..1c8357ad6
--- /dev/null
+++ b/sound/ac97/codec.c
@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  Copyright (C) 2016 Robert Jarzmik <robert.jarzmik@free.fr>
+ */
+
+#include <sound/ac97_codec.h>
+#include <sound/ac97/codec.h>
+#include <sound/ac97/controller.h>
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <sound/soc.h>	/* For compat_ac97_* */
+
diff --git a/sound/ac97/snd_ac97_compat.c b/sound/ac97/snd_ac97_compat.c
new file mode 100644
index 000000000..1a89286d1
--- /dev/null
+++ b/sound/ac97/snd_ac97_compat.c
@@ -0,0 +1,120 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  Copyright (C) 2016 Robert Jarzmik <robert.jarzmik@free.fr>
+ */
+
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <sound/ac97/codec.h>
+#include <sound/ac97/compat.h>
+#include <sound/ac97/controller.h>
+#include <sound/soc.h>
+
+#include "ac97_core.h"
+
+static void compat_ac97_release(struct device *dev)
+{
+	kfree(to_ac97_t(dev));
+}
+
+static void compat_ac97_reset(struct snd_ac97 *ac97)
+{
+	struct ac97_codec_device *adev = to_ac97_device(ac97->private_data);
+	struct ac97_controller *actrl = adev->ac97_ctrl;
+
+	if (actrl->ops->reset)
+		actrl->ops->reset(actrl);
+}
+
+static void compat_ac97_warm_reset(struct snd_ac97 *ac97)
+{
+	struct ac97_codec_device *adev = to_ac97_device(ac97->private_data);
+	struct ac97_controller *actrl = adev->ac97_ctrl;
+
+	if (actrl->ops->warm_reset)
+		actrl->ops->warm_reset(actrl);
+}
+
+static void compat_ac97_write(struct snd_ac97 *ac97, unsigned short reg,
+			      unsigned short val)
+{
+	struct ac97_codec_device *adev = to_ac97_device(ac97->private_data);
+	struct ac97_controller *actrl = adev->ac97_ctrl;
+
+	actrl->ops->write(actrl, ac97->num, reg, val);
+}
+
+static unsigned short compat_ac97_read(struct snd_ac97 *ac97,
+				       unsigned short reg)
+{
+	struct ac97_codec_device *adev = to_ac97_device(ac97->private_data);
+	struct ac97_controller *actrl = adev->ac97_ctrl;
+
+	return actrl->ops->read(actrl, ac97->num, reg);
+}
+
+static const struct snd_ac97_bus_ops compat_snd_ac97_bus_ops = {
+	.reset = compat_ac97_reset,
+	.warm_reset = compat_ac97_warm_reset,
+	.write = compat_ac97_write,
+	.read = compat_ac97_read,
+};
+
+static struct snd_ac97_bus compat_soc_ac97_bus = {
+	.ops = &compat_snd_ac97_bus_ops,
+};
+
+struct snd_ac97 *snd_ac97_compat_alloc(struct ac97_codec_device *adev)
+{
+	struct snd_ac97 *ac97;
+	int ret;
+
+	ac97 = kzalloc_obj(struct snd_ac97);
+	if (ac97 == NULL)
+		return ERR_PTR(-ENOMEM);
+
+	ac97->private_data = adev;
+	ac97->bus = &compat_soc_ac97_bus;
+
+	ac97->dev.parent = &adev->dev;
+	ac97->dev.release = compat_ac97_release;
+	dev_set_name(&ac97->dev, "%s-compat", dev_name(&adev->dev));
+	ret = device_register(&ac97->dev);
+	if (ret) {
+		put_device(&ac97->dev);
+		return ERR_PTR(ret);
+	}
+
+	return ac97;
+}
+EXPORT_SYMBOL_GPL(snd_ac97_compat_alloc);
+
+void snd_ac97_compat_release(struct snd_ac97 *ac97)
+{
+	device_unregister(&ac97->dev);
+}
+EXPORT_SYMBOL_GPL(snd_ac97_compat_release);
+
+int snd_ac97_reset(struct snd_ac97 *ac97, bool try_warm, unsigned int id,
+	unsigned int id_mask)
+{
+	struct ac97_codec_device *adev = to_ac97_device(ac97->private_data);
+	struct ac97_controller *actrl = adev->ac97_ctrl;
+	unsigned int scanned;
+
+	if (try_warm) {
+		compat_ac97_warm_reset(ac97);
+		scanned = snd_ac97_bus_scan_one(actrl, adev->num);
+		if (ac97_ids_match(scanned, adev->vendor_id, id_mask))
+			return 1;
+	}
+
+	compat_ac97_reset(ac97);
+	compat_ac97_warm_reset(ac97);
+	scanned = snd_ac97_bus_scan_one(actrl, adev->num);
+	if (ac97_ids_match(scanned, adev->vendor_id, id_mask))
+		return 0;
+
+	return -ENODEV;
+}
+EXPORT_SYMBOL_GPL(snd_ac97_reset);