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 <sound/asound.h>
 30
 31#include "sst-dsp.h"
 32#include "sst-dsp-priv.h"
 33#include "sst-ipc.h"
 34
 35/* IPC message timeout (msecs) */
 36#define IPC_TIMEOUT_MSECS	300
 37
 38#define IPC_EMPTY_LIST_SIZE	8
 39
 40/* locks held by caller */
 41static struct ipc_message *msg_get_empty(struct sst_generic_ipc *ipc)
 42{
 43	struct ipc_message *msg = NULL;
 44
 45	if (!list_empty(&ipc->empty_list)) {
 46		msg = list_first_entry(&ipc->empty_list, struct ipc_message,
 47			list);
 48		list_del(&msg->list);
 49	}
 50
 51	return msg;
 52}
 53
 54static int tx_wait_done(struct sst_generic_ipc *ipc,
 55	struct ipc_message *msg, void *rx_data)
 56{
 57	unsigned long flags;
 58	int ret;
 59
 60	/* wait for DSP completion (in all cases atm inc pending) */
 61	ret = wait_event_timeout(msg->waitq, msg->complete,
 62		msecs_to_jiffies(IPC_TIMEOUT_MSECS));
 63
 64	spin_lock_irqsave(&ipc->dsp->spinlock, flags);
 65	if (ret == 0) {
 66		if (ipc->ops.shim_dbg != NULL)
 67			ipc->ops.shim_dbg(ipc, "message timeout");
 68
 69		list_del(&msg->list);
 70		ret = -ETIMEDOUT;
 71	} else {
 72
 73		/* copy the data returned from DSP */
 74		if (msg->rx_size)
 75			memcpy(rx_data, msg->rx_data, msg->rx_size);
 76		ret = msg->errno;
 77	}
 78
 79	list_add_tail(&msg->list, &ipc->empty_list);
 80	spin_unlock_irqrestore(&ipc->dsp->spinlock, flags);
 81	return ret;
 82}
 83
 84static int ipc_tx_message(struct sst_generic_ipc *ipc, u64 header,
 85	void *tx_data, size_t tx_bytes, void *rx_data,
 86	size_t rx_bytes, int wait)
 87{
 88	struct ipc_message *msg;
 89	unsigned long flags;
 90
 91	spin_lock_irqsave(&ipc->dsp->spinlock, flags);
 92
 93	msg = msg_get_empty(ipc);
 94	if (msg == NULL) {
 95		spin_unlock_irqrestore(&ipc->dsp->spinlock, flags);
 96		return -EBUSY;
 97	}
 98
 99	msg->header = header;
100	msg->tx_size = tx_bytes;
101	msg->rx_size = rx_bytes;
102	msg->wait = wait;
103	msg->errno = 0;
104	msg->pending = false;
105	msg->complete = false;
106
107	if ((tx_bytes) && (ipc->ops.tx_data_copy != NULL))
108		ipc->ops.tx_data_copy(msg, tx_data, tx_bytes);
109
110	list_add_tail(&msg->list, &ipc->tx_list);
111	schedule_work(&ipc->kwork);
112	spin_unlock_irqrestore(&ipc->dsp->spinlock, flags);
113
114	if (wait)
115		return tx_wait_done(ipc, msg, rx_data);
116	else
117		return 0;
118}
119
120static int msg_empty_list_init(struct sst_generic_ipc *ipc)
121{
122	int i;
123
124	ipc->msg = kzalloc(sizeof(struct ipc_message) *
125		IPC_EMPTY_LIST_SIZE, GFP_KERNEL);
126	if (ipc->msg == NULL)
127		return -ENOMEM;
128
129	for (i = 0; i < IPC_EMPTY_LIST_SIZE; i++) {
130		ipc->msg[i].tx_data = kzalloc(ipc->tx_data_max_size, GFP_KERNEL);
131		if (ipc->msg[i].tx_data == NULL)
132			goto free_mem;
133
134		ipc->msg[i].rx_data = kzalloc(ipc->rx_data_max_size, GFP_KERNEL);
135		if (ipc->msg[i].rx_data == NULL) {
136			kfree(ipc->msg[i].tx_data);
137			goto free_mem;
138		}
139
140		init_waitqueue_head(&ipc->msg[i].waitq);
141		list_add(&ipc->msg[i].list, &ipc->empty_list);
142	}
143
144	return 0;
145
146free_mem:
147	while (i > 0) {
148		kfree(ipc->msg[i-1].tx_data);
149		kfree(ipc->msg[i-1].rx_data);
150		--i;
151	}
152	kfree(ipc->msg);
153
154	return -ENOMEM;
155}
156
157static void ipc_tx_msgs(struct work_struct *work)
158{
159	struct sst_generic_ipc *ipc =
160		container_of(work, struct sst_generic_ipc, kwork);
161	struct ipc_message *msg;
162
163	spin_lock_irq(&ipc->dsp->spinlock);
164
165	while (!list_empty(&ipc->tx_list) && !ipc->pending) {
166		/* if the DSP is busy, we will TX messages after IRQ.
167		 * also postpone if we are in the middle of processing
168		 * completion irq
169		 */
170		if (ipc->ops.is_dsp_busy && ipc->ops.is_dsp_busy(ipc->dsp)) {
171			dev_dbg(ipc->dev, "ipc_tx_msgs dsp busy\n");
172			break;
173		}
174
175		msg = list_first_entry(&ipc->tx_list, struct ipc_message, list);
176		list_move(&msg->list, &ipc->rx_list);
177
178		if (ipc->ops.tx_msg != NULL)
179			ipc->ops.tx_msg(ipc, msg);
180	}
181
182	spin_unlock_irq(&ipc->dsp->spinlock);
183}
184
185int sst_ipc_tx_message_wait(struct sst_generic_ipc *ipc, u64 header,
186	void *tx_data, size_t tx_bytes, void *rx_data, size_t rx_bytes)
187{
188	int ret;
189
190	/*
191	 * DSP maybe in lower power active state, so
192	 * check if the DSP supports DSP lp On method
193	 * if so invoke that before sending IPC
194	 */
195	if (ipc->ops.check_dsp_lp_on)
196		if (ipc->ops.check_dsp_lp_on(ipc->dsp, true))
197			return -EIO;
198
199	ret = ipc_tx_message(ipc, header, tx_data, tx_bytes,
200		rx_data, rx_bytes, 1);
201
202	if (ipc->ops.check_dsp_lp_on)
203		if (ipc->ops.check_dsp_lp_on(ipc->dsp, false))
204			return -EIO;
205
206	return ret;
207}
208EXPORT_SYMBOL_GPL(sst_ipc_tx_message_wait);
209
210int sst_ipc_tx_message_nowait(struct sst_generic_ipc *ipc, u64 header,
211	void *tx_data, size_t tx_bytes)
212{
213	return ipc_tx_message(ipc, header, tx_data, tx_bytes,
214		NULL, 0, 0);
215}
216EXPORT_SYMBOL_GPL(sst_ipc_tx_message_nowait);
217
218int sst_ipc_tx_message_nopm(struct sst_generic_ipc *ipc, u64 header,
219	void *tx_data, size_t tx_bytes, void *rx_data, size_t rx_bytes)
220{
221	return ipc_tx_message(ipc, header, tx_data, tx_bytes,
222		rx_data, rx_bytes, 1);
223}
224EXPORT_SYMBOL_GPL(sst_ipc_tx_message_nopm);
225
226struct ipc_message *sst_ipc_reply_find_msg(struct sst_generic_ipc *ipc,
227	u64 header)
228{
229	struct ipc_message *msg;
230	u64 mask;
231
232	if (ipc->ops.reply_msg_match != NULL)
233		header = ipc->ops.reply_msg_match(header, &mask);
234
235	if (list_empty(&ipc->rx_list)) {
236		dev_err(ipc->dev, "error: rx list empty but received 0x%llx\n",
237			header);
238		return NULL;
239	}
240
241	list_for_each_entry(msg, &ipc->rx_list, list) {
242		if ((msg->header & mask) == header)
243			return msg;
244	}
245
246	return NULL;
247}
248EXPORT_SYMBOL_GPL(sst_ipc_reply_find_msg);
249
250/* locks held by caller */
251void sst_ipc_tx_msg_reply_complete(struct sst_generic_ipc *ipc,
252	struct ipc_message *msg)
253{
254	msg->complete = true;
255
256	if (!msg->wait)
257		list_add_tail(&msg->list, &ipc->empty_list);
258	else
259		wake_up(&msg->waitq);
260}
261EXPORT_SYMBOL_GPL(sst_ipc_tx_msg_reply_complete);
262
263void sst_ipc_drop_all(struct sst_generic_ipc *ipc)
264{
265	struct ipc_message *msg, *tmp;
266	unsigned long flags;
267	int tx_drop_cnt = 0, rx_drop_cnt = 0;
268
269	/* drop all TX and Rx messages before we stall + reset DSP */
270	spin_lock_irqsave(&ipc->dsp->spinlock, flags);
271
272	list_for_each_entry_safe(msg, tmp, &ipc->tx_list, list) {
273		list_move(&msg->list, &ipc->empty_list);
274		tx_drop_cnt++;
275	}
276
277	list_for_each_entry_safe(msg, tmp, &ipc->rx_list, list) {
278		list_move(&msg->list, &ipc->empty_list);
279		rx_drop_cnt++;
280	}
281
282	spin_unlock_irqrestore(&ipc->dsp->spinlock, flags);
283
284	if (tx_drop_cnt || rx_drop_cnt)
285		dev_err(ipc->dev, "dropped IPC msg RX=%d, TX=%d\n",
286			tx_drop_cnt, rx_drop_cnt);
287}
288EXPORT_SYMBOL_GPL(sst_ipc_drop_all);
289
290int sst_ipc_init(struct sst_generic_ipc *ipc)
291{
292	int ret;
293
294	INIT_LIST_HEAD(&ipc->tx_list);
295	INIT_LIST_HEAD(&ipc->rx_list);
296	INIT_LIST_HEAD(&ipc->empty_list);
297	init_waitqueue_head(&ipc->wait_txq);
298
299	ret = msg_empty_list_init(ipc);
300	if (ret < 0)
301		return -ENOMEM;
302
303	INIT_WORK(&ipc->kwork, ipc_tx_msgs);
304	return 0;
305}
306EXPORT_SYMBOL_GPL(sst_ipc_init);
307
308void sst_ipc_fini(struct sst_generic_ipc *ipc)
309{
310	int i;
311
312	cancel_work_sync(&ipc->kwork);
313
314	if (ipc->msg) {
315		for (i = 0; i < IPC_EMPTY_LIST_SIZE; i++) {
316			kfree(ipc->msg[i].tx_data);
317			kfree(ipc->msg[i].rx_data);
318		}
319		kfree(ipc->msg);
320	}
321}
322EXPORT_SYMBOL_GPL(sst_ipc_fini);
323
324/* Module information */
325MODULE_AUTHOR("Jin Yao");
326MODULE_DESCRIPTION("Intel SST IPC generic");
327MODULE_LICENSE("GPL v2");