1/*
2 * Intel SST generic IPC Support
3 *
4 * Copyright (C) 2015, Intel Corporation. All rights reserved.
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License version
8 * 2 as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13 * GNU General Public License for more details.
14 *
15 */
16
17#include <linux/types.h>
18#include <linux/kernel.h>
19#include <linux/list.h>
20#include <linux/wait.h>
21#include <linux/module.h>
22#include <linux/spinlock.h>
23#include <linux/device.h>
24#include <linux/slab.h>
25#include <linux/workqueue.h>
26#include <linux/sched.h>
27#include <linux/delay.h>
28#include <linux/platform_device.h>
29#include <linux/kthread.h>
30#include <sound/asound.h>
31
32#include "sst-dsp.h"
33#include "sst-dsp-priv.h"
34#include "sst-ipc.h"
35
36/* IPC message timeout (msecs) */
37#define IPC_TIMEOUT_MSECS	300
38
39#define IPC_EMPTY_LIST_SIZE	8
40
41/* locks held by caller */
42static struct ipc_message *msg_get_empty(struct sst_generic_ipc *ipc)
43{
44	struct ipc_message *msg = NULL;
45
46	if (!list_empty(&ipc->empty_list)) {
47		msg = list_first_entry(&ipc->empty_list, struct ipc_message,
48			list);
49		list_del(&msg->list);
50	}
51
52	return msg;
53}
54
55static int tx_wait_done(struct sst_generic_ipc *ipc,
56	struct ipc_message *msg, void *rx_data)
57{
58	unsigned long flags;
59	int ret;
60
61	/* wait for DSP completion (in all cases atm inc pending) */
62	ret = wait_event_timeout(msg->waitq, msg->complete,
63		msecs_to_jiffies(IPC_TIMEOUT_MSECS));
64
65	spin_lock_irqsave(&ipc->dsp->spinlock, flags);
66	if (ret == 0) {
67		if (ipc->ops.shim_dbg != NULL)
68			ipc->ops.shim_dbg(ipc, "message timeout");
69
70		list_del(&msg->list);
71		ret = -ETIMEDOUT;
72	} else {
73
74		/* copy the data returned from DSP */
75		if (msg->rx_size)
76			memcpy(rx_data, msg->rx_data, msg->rx_size);
77		ret = msg->errno;
78	}
79
80	list_add_tail(&msg->list, &ipc->empty_list);
81	spin_unlock_irqrestore(&ipc->dsp->spinlock, flags);
82	return ret;
83}
84
85static int ipc_tx_message(struct sst_generic_ipc *ipc, u64 header,
86	void *tx_data, size_t tx_bytes, void *rx_data,
87	size_t rx_bytes, int wait)
88{
89	struct ipc_message *msg;
90	unsigned long flags;
91
92	spin_lock_irqsave(&ipc->dsp->spinlock, flags);
93
94	msg = msg_get_empty(ipc);
95	if (msg == NULL) {
96		spin_unlock_irqrestore(&ipc->dsp->spinlock, flags);
97		return -EBUSY;
98	}
99
100	msg->header = header;
101	msg->tx_size = tx_bytes;
102	msg->rx_size = rx_bytes;
103	msg->wait = wait;
104	msg->errno = 0;
105	msg->pending = false;
106	msg->complete = false;
107
108	if ((tx_bytes) && (ipc->ops.tx_data_copy != NULL))
109		ipc->ops.tx_data_copy(msg, tx_data, tx_bytes);
110
111	list_add_tail(&msg->list, &ipc->tx_list);
112	spin_unlock_irqrestore(&ipc->dsp->spinlock, flags);
113
114	queue_kthread_work(&ipc->kworker, &ipc->kwork);
115
116	if (wait)
117		return tx_wait_done(ipc, msg, rx_data);
118	else
119		return 0;
120}
121
122static int msg_empty_list_init(struct sst_generic_ipc *ipc)
123{
124	int i;
125
126	ipc->msg = kzalloc(sizeof(struct ipc_message) *
127		IPC_EMPTY_LIST_SIZE, GFP_KERNEL);
128	if (ipc->msg == NULL)
129		return -ENOMEM;
130
131	for (i = 0; i < IPC_EMPTY_LIST_SIZE; i++) {
132		init_waitqueue_head(&ipc->msg[i].waitq);
133		list_add(&ipc->msg[i].list, &ipc->empty_list);
134	}
135
136	return 0;
137}
138
139static void ipc_tx_msgs(struct kthread_work *work)
140{
141	struct sst_generic_ipc *ipc =
142		container_of(work, struct sst_generic_ipc, kwork);
143	struct ipc_message *msg;
144	unsigned long flags;
145	u64 ipcx;
146
147	spin_lock_irqsave(&ipc->dsp->spinlock, flags);
148
149	if (list_empty(&ipc->tx_list) || ipc->pending) {
150		spin_unlock_irqrestore(&ipc->dsp->spinlock, flags);
151		return;
152	}
153
154	/* if the DSP is busy, we will TX messages after IRQ.
155	 * also postpone if we are in the middle of procesing completion irq*/
156	ipcx = sst_dsp_shim_read_unlocked(ipc->dsp, SST_IPCX);
157	if (ipcx & (SST_IPCX_BUSY | SST_IPCX_DONE)) {
158		spin_unlock_irqrestore(&ipc->dsp->spinlock, flags);
159		return;
160	}
161
162	msg = list_first_entry(&ipc->tx_list, struct ipc_message, list);
163	list_move(&msg->list, &ipc->rx_list);
164
165	if (ipc->ops.tx_msg != NULL)
166		ipc->ops.tx_msg(ipc, msg);
167
168	spin_unlock_irqrestore(&ipc->dsp->spinlock, flags);
169}
170
171int sst_ipc_tx_message_wait(struct sst_generic_ipc *ipc, u64 header,
172	void *tx_data, size_t tx_bytes, void *rx_data, size_t rx_bytes)
173{
174	return ipc_tx_message(ipc, header, tx_data, tx_bytes,
175		rx_data, rx_bytes, 1);
176}
177EXPORT_SYMBOL_GPL(sst_ipc_tx_message_wait);
178
179int sst_ipc_tx_message_nowait(struct sst_generic_ipc *ipc, u64 header,
180	void *tx_data, size_t tx_bytes)
181{
182	return ipc_tx_message(ipc, header, tx_data, tx_bytes,
183		NULL, 0, 0);
184}
185EXPORT_SYMBOL_GPL(sst_ipc_tx_message_nowait);
186
187struct ipc_message *sst_ipc_reply_find_msg(struct sst_generic_ipc *ipc,
188	u64 header)
189{
190	struct ipc_message *msg;
191	u64 mask;
192
193	if (ipc->ops.reply_msg_match != NULL)
194		header = ipc->ops.reply_msg_match(header, &mask);
195
196	if (list_empty(&ipc->rx_list)) {
197		dev_err(ipc->dev, "error: rx list empty but received 0x%llx\n",
198			header);
199		return NULL;
200	}
201
202	list_for_each_entry(msg, &ipc->rx_list, list) {
203		if ((msg->header & mask) == header)
204			return msg;
205	}
206
207	return NULL;
208}
209EXPORT_SYMBOL_GPL(sst_ipc_reply_find_msg);
210
211/* locks held by caller */
212void sst_ipc_tx_msg_reply_complete(struct sst_generic_ipc *ipc,
213	struct ipc_message *msg)
214{
215	msg->complete = true;
216
217	if (!msg->wait)
218		list_add_tail(&msg->list, &ipc->empty_list);
219	else
220		wake_up(&msg->waitq);
221}
222EXPORT_SYMBOL_GPL(sst_ipc_tx_msg_reply_complete);
223
224void sst_ipc_drop_all(struct sst_generic_ipc *ipc)
225{
226	struct ipc_message *msg, *tmp;
227	unsigned long flags;
228	int tx_drop_cnt = 0, rx_drop_cnt = 0;
229
230	/* drop all TX and Rx messages before we stall + reset DSP */
231	spin_lock_irqsave(&ipc->dsp->spinlock, flags);
232
233	list_for_each_entry_safe(msg, tmp, &ipc->tx_list, list) {
234		list_move(&msg->list, &ipc->empty_list);
235		tx_drop_cnt++;
236	}
237
238	list_for_each_entry_safe(msg, tmp, &ipc->rx_list, list) {
239		list_move(&msg->list, &ipc->empty_list);
240		rx_drop_cnt++;
241	}
242
243	spin_unlock_irqrestore(&ipc->dsp->spinlock, flags);
244
245	if (tx_drop_cnt || rx_drop_cnt)
246		dev_err(ipc->dev, "dropped IPC msg RX=%d, TX=%d\n",
247			tx_drop_cnt, rx_drop_cnt);
248}
249EXPORT_SYMBOL_GPL(sst_ipc_drop_all);
250
251int sst_ipc_init(struct sst_generic_ipc *ipc)
252{
253	int ret;
254
255	INIT_LIST_HEAD(&ipc->tx_list);
256	INIT_LIST_HEAD(&ipc->rx_list);
257	INIT_LIST_HEAD(&ipc->empty_list);
258	init_waitqueue_head(&ipc->wait_txq);
259
260	ret = msg_empty_list_init(ipc);
261	if (ret < 0)
262		return -ENOMEM;
263
264	/* start the IPC message thread */
265	init_kthread_worker(&ipc->kworker);
266	ipc->tx_thread = kthread_run(kthread_worker_fn,
267					&ipc->kworker, "%s",
268					dev_name(ipc->dev));
269	if (IS_ERR(ipc->tx_thread)) {
270		dev_err(ipc->dev, "error: failed to create message TX task\n");
271		ret = PTR_ERR(ipc->tx_thread);
272		kfree(ipc->msg);
273		return ret;
274	}
275
276	init_kthread_work(&ipc->kwork, ipc_tx_msgs);
277	return 0;
278}
279EXPORT_SYMBOL_GPL(sst_ipc_init);
280
281void sst_ipc_fini(struct sst_generic_ipc *ipc)
282{
283	if (ipc->tx_thread)
284		kthread_stop(ipc->tx_thread);
285
286	if (ipc->msg)
287		kfree(ipc->msg);
288}
289EXPORT_SYMBOL_GPL(sst_ipc_fini);
290
291/* Module information */
292MODULE_AUTHOR("Jin Yao");
293MODULE_DESCRIPTION("Intel SST IPC generic");
294MODULE_LICENSE("GPL v2");
295