sof-client-ipc-kernel-injector.c

  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
 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	ret = pm_runtime_put_autosuspend(dev);
 69	if (ret < 0)
 70		dev_err_ratelimited(dev, "debugfs write failed to idle %d\n", ret);
 71
 72	return count;
 73};
 74
 75static int sof_msg_inject_dfs_release(struct inode *inode, struct file *file)
 76{
 77	debugfs_file_put(file->f_path.dentry);
 78
 79	return 0;
 80}
 81
 82static const struct file_operations sof_kernel_msg_inject_fops = {
 83	.open = sof_msg_inject_dfs_open,
 84	.write = sof_kernel_msg_inject_dfs_write,
 85	.release = sof_msg_inject_dfs_release,
 86
 87	.owner = THIS_MODULE,
 88};
 89
 90static int sof_msg_inject_probe(struct auxiliary_device *auxdev,
 91				const struct auxiliary_device_id *id)
 92{
 93	struct sof_client_dev *cdev = auxiliary_dev_to_sof_client_dev(auxdev);
 94	struct dentry *debugfs_root = sof_client_get_debugfs_root(cdev);
 95	struct device *dev = &auxdev->dev;
 96	struct sof_msg_inject_priv *priv;
 97	size_t alloc_size;
 98
 99	/* allocate memory for client data */
100	priv = devm_kzalloc(&auxdev->dev, sizeof(*priv), GFP_KERNEL);
101	if (!priv)
102		return -ENOMEM;
103
104	priv->max_msg_size = sof_client_get_ipc_max_payload_size(cdev);
105	alloc_size = priv->max_msg_size;
106	priv->kernel_buffer = devm_kmalloc(dev, alloc_size, GFP_KERNEL);
107
108	if (!priv->kernel_buffer)
109		return -ENOMEM;
110
111	cdev->data = priv;
112
113	priv->kernel_dfs_file = debugfs_create_file("kernel_ipc_msg_inject", 0644,
114						    debugfs_root, cdev,
115						    &sof_kernel_msg_inject_fops);
116
117	/* enable runtime PM */
118	pm_runtime_set_autosuspend_delay(dev, SOF_IPC_CLIENT_SUSPEND_DELAY_MS);
119	pm_runtime_use_autosuspend(dev);
120	pm_runtime_set_active(dev);
121	pm_runtime_enable(dev);
122	pm_runtime_mark_last_busy(dev);
123	pm_runtime_idle(dev);
124
125	return 0;
126}
127
128static void sof_msg_inject_remove(struct auxiliary_device *auxdev)
129{
130	struct sof_client_dev *cdev = auxiliary_dev_to_sof_client_dev(auxdev);
131	struct sof_msg_inject_priv *priv = cdev->data;
132
133	pm_runtime_disable(&auxdev->dev);
134
135	debugfs_remove(priv->kernel_dfs_file);
136}
137
138static const struct auxiliary_device_id sof_msg_inject_client_id_table[] = {
139	{ .name = "snd_sof.kernel_injector" },
140	{},
141};
142MODULE_DEVICE_TABLE(auxiliary, sof_msg_inject_client_id_table);
143
144/*
145 * No need for driver pm_ops as the generic pm callbacks in the auxiliary bus
146 * type are enough to ensure that the parent SOF device resumes to bring the DSP
147 * back to D0.
148 * Driver name will be set based on KBUILD_MODNAME.
149 */
150static struct auxiliary_driver sof_msg_inject_client_drv = {
151	.probe = sof_msg_inject_probe,
152	.remove = sof_msg_inject_remove,
153
154	.id_table = sof_msg_inject_client_id_table,
155};
156
157module_auxiliary_driver(sof_msg_inject_client_drv);
158
159MODULE_LICENSE("GPL");
160MODULE_DESCRIPTION("SOF IPC Kernel Injector Client Driver");
161MODULE_IMPORT_NS("SND_SOC_SOF_CLIENT");