xref: /linux/sound/soc/sof/sof-client-ipc-kernel-injector.c (revision daa121128a2d2ac6006159e2c47676e4fcd21eab)
1 // SPDX-License-Identifier: GPL-2.0-only
2 //
3 // Copyright(c) 2023 Google Inc
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 
19 struct sof_msg_inject_priv {
20 	struct dentry *kernel_dfs_file;
21 	size_t max_msg_size;
22 
23 	void *kernel_buffer;
24 };
25 
26 static 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 
40 static 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 
76 static 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 
83 static 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 
91 static 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 
129 static 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 
139 static const struct auxiliary_device_id sof_msg_inject_client_id_table[] = {
140 	{ .name = "snd_sof.kernel_injector" },
141 	{},
142 };
143 MODULE_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  */
151 static 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 
158 module_auxiliary_driver(sof_msg_inject_client_drv);
159 
160 MODULE_DESCRIPTION("SOF IPC Kernel Injector Client Driver");
161 MODULE_LICENSE("GPL");
162 MODULE_IMPORT_NS(SND_SOC_SOF_CLIENT);
163