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		ipc->msg[i].tx_data = kzalloc(ipc->tx_data_max_size, GFP_KERNEL);
133		if (ipc->msg[i].tx_data == NULL)
134			goto free_mem;
135
136		ipc->msg[i].rx_data = kzalloc(ipc->rx_data_max_size, GFP_KERNEL);
137		if (ipc->msg[i].rx_data == NULL) {
138			kfree(ipc->msg[i].tx_data);
139			goto free_mem;
140		}
141
142		init_waitqueue_head(&ipc->msg[i].waitq);
143		list_add(&ipc->msg[i].list, &ipc->empty_list);
144	}
145
146	return 0;
147
148free_mem:
149	while (i > 0) {
150		kfree(ipc->msg[i-1].tx_data);
151		kfree(ipc->msg[i-1].rx_data);
152		--i;
153	}
154	kfree(ipc->msg);
155
156	return -ENOMEM;
157}
158
159static void ipc_tx_msgs(struct kthread_work *work)
160{
161	struct sst_generic_ipc *ipc =
162		container_of(work, struct sst_generic_ipc, kwork);
163	struct ipc_message *msg;
164	unsigned long flags;
165
166	spin_lock_irqsave(&ipc->dsp->spinlock, flags);
167
168	if (list_empty(&ipc->tx_list) || ipc->pending) {
169		spin_unlock_irqrestore(&ipc->dsp->spinlock, flags);
170		return;
171	}
172
173	/* if the DSP is busy, we will TX messages after IRQ.
174	 * also postpone if we are in the middle of procesing completion irq*/
175	if (ipc->ops.is_dsp_busy && ipc->ops.is_dsp_busy(ipc->dsp)) {
176		dev_dbg(ipc->dev, "ipc_tx_msgs dsp busy\n");
177		spin_unlock_irqrestore(&ipc->dsp->spinlock, flags);
178		return;
179	}
180
181	msg = list_first_entry(&ipc->tx_list, struct ipc_message, list);
182	list_move(&msg->list, &ipc->rx_list);
183
184	if (ipc->ops.tx_msg != NULL)
185		ipc->ops.tx_msg(ipc, msg);
186
187	spin_unlock_irqrestore(&ipc->dsp->spinlock, flags);
188}
189
190int sst_ipc_tx_message_wait(struct sst_generic_ipc *ipc, u64 header,
191	void *tx_data, size_t tx_bytes, void *rx_data, size_t rx_bytes)
192{
193	return ipc_tx_message(ipc, header, tx_data, tx_bytes,
194		rx_data, rx_bytes, 1);
195}
196EXPORT_SYMBOL_GPL(sst_ipc_tx_message_wait);
197
198int sst_ipc_tx_message_nowait(struct sst_generic_ipc *ipc, u64 header,
199	void *tx_data, size_t tx_bytes)
200{
201	return ipc_tx_message(ipc, header, tx_data, tx_bytes,
202		NULL, 0, 0);
203}
204EXPORT_SYMBOL_GPL(sst_ipc_tx_message_nowait);
205
206struct ipc_message *sst_ipc_reply_find_msg(struct sst_generic_ipc *ipc,
207	u64 header)
208{
209	struct ipc_message *msg;
210	u64 mask;
211
212	if (ipc->ops.reply_msg_match != NULL)
213		header = ipc->ops.reply_msg_match(header, &mask);
214
215	if (list_empty(&ipc->rx_list)) {
216		dev_err(ipc->dev, "error: rx list empty but received 0x%llx\n",
217			header);
218		return NULL;
219	}
220
221	list_for_each_entry(msg, &ipc->rx_list, list) {
222		if ((msg->header & mask) == header)
223			return msg;
224	}
225
226	return NULL;
227}
228EXPORT_SYMBOL_GPL(sst_ipc_reply_find_msg);
229
230/* locks held by caller */
231void sst_ipc_tx_msg_reply_complete(struct sst_generic_ipc *ipc,
232	struct ipc_message *msg)
233{
234	msg->complete = true;
235
236	if (!msg->wait)
237		list_add_tail(&msg->list, &ipc->empty_list);
238	else
239		wake_up(&msg->waitq);
240}
241EXPORT_SYMBOL_GPL(sst_ipc_tx_msg_reply_complete);
242
243void sst_ipc_drop_all(struct sst_generic_ipc *ipc)
244{
245	struct ipc_message *msg, *tmp;
246	unsigned long flags;
247	int tx_drop_cnt = 0, rx_drop_cnt = 0;
248
249	/* drop all TX and Rx messages before we stall + reset DSP */
250	spin_lock_irqsave(&ipc->dsp->spinlock, flags);
251
252	list_for_each_entry_safe(msg, tmp, &ipc->tx_list, list) {
253		list_move(&msg->list, &ipc->empty_list);
254		tx_drop_cnt++;
255	}
256
257	list_for_each_entry_safe(msg, tmp, &ipc->rx_list, list) {
258		list_move(&msg->list, &ipc->empty_list);
259		rx_drop_cnt++;
260	}
261
262	spin_unlock_irqrestore(&ipc->dsp->spinlock, flags);
263
264	if (tx_drop_cnt || rx_drop_cnt)
265		dev_err(ipc->dev, "dropped IPC msg RX=%d, TX=%d\n",
266			tx_drop_cnt, rx_drop_cnt);
267}
268EXPORT_SYMBOL_GPL(sst_ipc_drop_all);
269
270int sst_ipc_init(struct sst_generic_ipc *ipc)
271{
272	int ret;
273
274	INIT_LIST_HEAD(&ipc->tx_list);
275	INIT_LIST_HEAD(&ipc->rx_list);
276	INIT_LIST_HEAD(&ipc->empty_list);
277	init_waitqueue_head(&ipc->wait_txq);
278
279	ret = msg_empty_list_init(ipc);
280	if (ret < 0)
281		return -ENOMEM;
282
283	/* start the IPC message thread */
284	init_kthread_worker(&ipc->kworker);
285	ipc->tx_thread = kthread_run(kthread_worker_fn,
286					&ipc->kworker, "%s",
287					dev_name(ipc->dev));
288	if (IS_ERR(ipc->tx_thread)) {
289		dev_err(ipc->dev, "error: failed to create message TX task\n");
290		ret = PTR_ERR(ipc->tx_thread);
291		kfree(ipc->msg);
292		return ret;
293	}
294
295	init_kthread_work(&ipc->kwork, ipc_tx_msgs);
296	return 0;
297}
298EXPORT_SYMBOL_GPL(sst_ipc_init);
299
300void sst_ipc_fini(struct sst_generic_ipc *ipc)
301{
302	int i;
303
304	if (ipc->tx_thread)
305		kthread_stop(ipc->tx_thread);
306
307	if (ipc->msg) {
308		for (i = 0; i < IPC_EMPTY_LIST_SIZE; i++) {
309			kfree(ipc->msg[i].tx_data);
310			kfree(ipc->msg[i].rx_data);
311		}
312		kfree(ipc->msg);
313	}
314}
315EXPORT_SYMBOL_GPL(sst_ipc_fini);
316
317/* Module information */
318MODULE_AUTHOR("Jin Yao");
319MODULE_DESCRIPTION("Intel SST IPC generic");
320MODULE_LICENSE("GPL v2");
321