1// SPDX-License-Identifier: GPL-2.0-only
2//
3// Copyright(c) 2023 Google Inc. All rights reserved.
4//
5// Author: Curtis Malainey <cujomalainey@chromium.org>
6//
7
8#include <linux/auxiliary_bus.h>
9#include <linux/debugfs.h>
10#include <linux/mod_devicetable.h>
11#include <linux/module.h>
12#include <linux/pm_runtime.h>
13#include <sound/sof/header.h>
14
15#include "sof-client.h"
16
17#define SOF_IPC_CLIENT_SUSPEND_DELAY_MS	3000
18
19struct sof_msg_inject_priv {
20	struct dentry *kernel_dfs_file;
21	size_t max_msg_size;
22
23	void *kernel_buffer;
24};
25
26static int sof_msg_inject_dfs_open(struct inode *inode, struct file *file)
27{
28	int ret = debugfs_file_get(file->f_path.dentry);
29
30	if (unlikely(ret))
31		return ret;
32
33	ret = simple_open(inode, file);
34	if (ret)
35		debugfs_file_put(file->f_path.dentry);
36
37	return ret;
38}
39
40static ssize_t sof_kernel_msg_inject_dfs_write(struct file *file, const char __user *buffer,
41					       size_t count, loff_t *ppos)
42{
43	struct sof_client_dev *cdev = file->private_data;
44	struct sof_msg_inject_priv *priv = cdev->data;
45	struct sof_ipc_cmd_hdr *hdr = priv->kernel_buffer;
46	struct device *dev = &cdev->auxdev.dev;
47	ssize_t size;
48	int ret;
49
50	if (*ppos)
51		return 0;
52
53	size = simple_write_to_buffer(priv->kernel_buffer, priv->max_msg_size,
54				      ppos, buffer, count);
55	if (size < 0)
56		return size;
57	if (size != count)
58		return -EFAULT;
59
60	ret = pm_runtime_resume_and_get(dev);
61	if (ret < 0 && ret != -EACCES) {
62		dev_err_ratelimited(dev, "debugfs write failed to resume %d\n", ret);
63		return ret;
64	}
65
66	sof_client_ipc_rx_message(cdev, hdr, priv->kernel_buffer);
67
68	pm_runtime_mark_last_busy(dev);
69	ret = pm_runtime_put_autosuspend(dev);
70	if (ret < 0)
71		dev_err_ratelimited(dev, "debugfs write failed to idle %d\n", ret);
72
73	return count;
74};
75
76static int sof_msg_inject_dfs_release(struct inode *inode, struct file *file)
77{
78	debugfs_file_put(file->f_path.dentry);
79
80	return 0;
81}
82
83static const struct file_operations sof_kernel_msg_inject_fops = {
84	.open = sof_msg_inject_dfs_open,
85	.write = sof_kernel_msg_inject_dfs_write,
86	.release = sof_msg_inject_dfs_release,
87
88	.owner = THIS_MODULE,
89};
90
91static int sof_msg_inject_probe(struct auxiliary_device *auxdev,
92				const struct auxiliary_device_id *id)
93{
94	struct sof_client_dev *cdev = auxiliary_dev_to_sof_client_dev(auxdev);
95	struct dentry *debugfs_root = sof_client_get_debugfs_root(cdev);
96	struct device *dev = &auxdev->dev;
97	struct sof_msg_inject_priv *priv;
98	size_t alloc_size;
99
100	/* allocate memory for client data */
101	priv = devm_kzalloc(&auxdev->dev, sizeof(*priv), GFP_KERNEL);
102	if (!priv)
103		return -ENOMEM;
104
105	priv->max_msg_size = sof_client_get_ipc_max_payload_size(cdev);
106	alloc_size = priv->max_msg_size;
107	priv->kernel_buffer = devm_kmalloc(dev, alloc_size, GFP_KERNEL);
108
109	if (!priv->kernel_buffer)
110		return -ENOMEM;
111
112	cdev->data = priv;
113
114	priv->kernel_dfs_file = debugfs_create_file("kernel_ipc_msg_inject", 0644,
115						    debugfs_root, cdev,
116						    &sof_kernel_msg_inject_fops);
117
118	/* enable runtime PM */
119	pm_runtime_set_autosuspend_delay(dev, SOF_IPC_CLIENT_SUSPEND_DELAY_MS);
120	pm_runtime_use_autosuspend(dev);
121	pm_runtime_set_active(dev);
122	pm_runtime_enable(dev);
123	pm_runtime_mark_last_busy(dev);
124	pm_runtime_idle(dev);
125
126	return 0;
127}
128
129static void sof_msg_inject_remove(struct auxiliary_device *auxdev)
130{
131	struct sof_client_dev *cdev = auxiliary_dev_to_sof_client_dev(auxdev);
132	struct sof_msg_inject_priv *priv = cdev->data;
133
134	pm_runtime_disable(&auxdev->dev);
135
136	debugfs_remove(priv->kernel_dfs_file);
137}
138
139static const struct auxiliary_device_id sof_msg_inject_client_id_table[] = {
140	{ .name = "snd_sof.kernel_injector" },
141	{},
142};
143MODULE_DEVICE_TABLE(auxiliary, sof_msg_inject_client_id_table);
144
145/*
146 * No need for driver pm_ops as the generic pm callbacks in the auxiliary bus
147 * type are enough to ensure that the parent SOF device resumes to bring the DSP
148 * back to D0.
149 * Driver name will be set based on KBUILD_MODNAME.
150 */
151static struct auxiliary_driver sof_msg_inject_client_drv = {
152	.probe = sof_msg_inject_probe,
153	.remove = sof_msg_inject_remove,
154
155	.id_table = sof_msg_inject_client_id_table,
156};
157
158module_auxiliary_driver(sof_msg_inject_client_drv);
159
160MODULE_DESCRIPTION("SOF IPC Kernel Injector Client Driver");
161MODULE_LICENSE("GPL");
162MODULE_IMPORT_NS(SND_SOC_SOF_CLIENT);
163