1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Interrupt bottom half (BH).
4 *
5 * Copyright (c) 2017-2020, Silicon Laboratories, Inc.
6 * Copyright (c) 2010, ST-Ericsson
7 */
8#include <linux/gpio/consumer.h>
9#include <net/mac80211.h>
10
11#include "bh.h"
12#include "wfx.h"
13#include "hwio.h"
14#include "traces.h"
15#include "hif_rx.h"
16#include "hif_api_cmd.h"
17
18static void device_wakeup(struct wfx_dev *wdev)
19{
20	int max_retry = 3;
21
22	if (!wdev->pdata.gpio_wakeup)
23		return;
24	if (gpiod_get_value_cansleep(wdev->pdata.gpio_wakeup) > 0)
25		return;
26
27	if (wfx_api_older_than(wdev, 1, 4)) {
28		gpiod_set_value_cansleep(wdev->pdata.gpio_wakeup, 1);
29		if (!completion_done(&wdev->hif.ctrl_ready))
30			usleep_range(2000, 2500);
31		return;
32	}
33	for (;;) {
34		gpiod_set_value_cansleep(wdev->pdata.gpio_wakeup, 1);
35		/* completion.h does not provide any function to wait completion without consume it
36		 * (a kind of wait_for_completion_done_timeout()). So we have to emulate it.
37		 */
38		if (wait_for_completion_timeout(&wdev->hif.ctrl_ready, msecs_to_jiffies(2))) {
39			complete(&wdev->hif.ctrl_ready);
40			return;
41		} else if (max_retry-- > 0) {
42			/* Older firmwares have a race in sleep/wake-up process.  Redo the process
43			 * is sufficient to unfreeze the chip.
44			 */
45			dev_err(wdev->dev, "timeout while wake up chip\n");
46			gpiod_set_value_cansleep(wdev->pdata.gpio_wakeup, 0);
47			usleep_range(2000, 2500);
48		} else {
49			dev_err(wdev->dev, "max wake-up retries reached\n");
50			return;
51		}
52	}
53}
54
55static void device_release(struct wfx_dev *wdev)
56{
57	if (!wdev->pdata.gpio_wakeup)
58		return;
59
60	gpiod_set_value_cansleep(wdev->pdata.gpio_wakeup, 0);
61}
62
63static int rx_helper(struct wfx_dev *wdev, size_t read_len, int *is_cnf)
64{
65	struct sk_buff *skb;
66	struct wfx_hif_msg *hif;
67	size_t alloc_len;
68	size_t computed_len;
69	int release_count;
70	int piggyback = 0;
71
72	WARN(read_len > round_down(0xFFF, 2) * sizeof(u16), "request exceed the chip capability");
73
74	/* Add 2 to take into account piggyback size */
75	alloc_len = wdev->hwbus_ops->align_size(wdev->hwbus_priv, read_len + 2);
76	skb = dev_alloc_skb(alloc_len);
77	if (!skb)
78		return -ENOMEM;
79
80	if (wfx_data_read(wdev, skb->data, alloc_len))
81		goto err;
82
83	piggyback = le16_to_cpup((__le16 *)(skb->data + alloc_len - 2));
84	_trace_piggyback(piggyback, false);
85
86	hif = (struct wfx_hif_msg *)skb->data;
87	WARN(hif->encrypted & 0x3, "encryption is unsupported");
88	if (WARN(read_len < sizeof(struct wfx_hif_msg), "corrupted read"))
89		goto err;
90	computed_len = le16_to_cpu(hif->len);
91	computed_len = round_up(computed_len, 2);
92	if (computed_len != read_len) {
93		dev_err(wdev->dev, "inconsistent message length: %zu != %zu\n",
94			computed_len, read_len);
95		print_hex_dump(KERN_INFO, "hif: ", DUMP_PREFIX_OFFSET, 16, 1,
96			       hif, read_len, true);
97		goto err;
98	}
99
100	if (!(hif->id & HIF_ID_IS_INDICATION)) {
101		(*is_cnf)++;
102		if (hif->id == HIF_CNF_ID_MULTI_TRANSMIT)
103			release_count =
104				((struct wfx_hif_cnf_multi_transmit *)hif->body)->num_tx_confs;
105		else
106			release_count = 1;
107		WARN(wdev->hif.tx_buffers_used < release_count, "corrupted buffer counter");
108		wdev->hif.tx_buffers_used -= release_count;
109	}
110	_trace_hif_recv(hif, wdev->hif.tx_buffers_used);
111
112	if (hif->id != HIF_IND_ID_EXCEPTION && hif->id != HIF_IND_ID_ERROR) {
113		if (hif->seqnum != wdev->hif.rx_seqnum)
114			dev_warn(wdev->dev, "wrong message sequence: %d != %d\n",
115				 hif->seqnum, wdev->hif.rx_seqnum);
116		wdev->hif.rx_seqnum = (hif->seqnum + 1) % (HIF_COUNTER_MAX + 1);
117	}
118
119	skb_put(skb, le16_to_cpu(hif->len));
120	/* wfx_handle_rx takes care on SKB livetime */
121	wfx_handle_rx(wdev, skb);
122	if (!wdev->hif.tx_buffers_used)
123		wake_up(&wdev->hif.tx_buffers_empty);
124
125	return piggyback;
126
127err:
128	if (skb)
129		dev_kfree_skb(skb);
130	return -EIO;
131}
132
133static int bh_work_rx(struct wfx_dev *wdev, int max_msg, int *num_cnf)
134{
135	size_t len;
136	int i;
137	int ctrl_reg, piggyback;
138
139	piggyback = 0;
140	for (i = 0; i < max_msg; i++) {
141		if (piggyback & CTRL_NEXT_LEN_MASK)
142			ctrl_reg = piggyback;
143		else if (try_wait_for_completion(&wdev->hif.ctrl_ready))
144			ctrl_reg = atomic_xchg(&wdev->hif.ctrl_reg, 0);
145		else
146			ctrl_reg = 0;
147		if (!(ctrl_reg & CTRL_NEXT_LEN_MASK))
148			return i;
149		/* ctrl_reg units are 16bits words */
150		len = (ctrl_reg & CTRL_NEXT_LEN_MASK) * 2;
151		piggyback = rx_helper(wdev, len, num_cnf);
152		if (piggyback < 0)
153			return i;
154		if (!(piggyback & CTRL_WLAN_READY))
155			dev_err(wdev->dev, "unexpected piggyback value: ready bit not set: %04x\n",
156				piggyback);
157	}
158	if (piggyback & CTRL_NEXT_LEN_MASK) {
159		ctrl_reg = atomic_xchg(&wdev->hif.ctrl_reg, piggyback);
160		complete(&wdev->hif.ctrl_ready);
161		if (ctrl_reg)
162			dev_err(wdev->dev, "unexpected IRQ happened: %04x/%04x\n",
163				ctrl_reg, piggyback);
164	}
165	return i;
166}
167
168static void tx_helper(struct wfx_dev *wdev, struct wfx_hif_msg *hif)
169{
170	int ret;
171	void *data;
172	bool is_encrypted = false;
173	size_t len = le16_to_cpu(hif->len);
174
175	WARN(len < sizeof(*hif), "try to send corrupted data");
176
177	hif->seqnum = wdev->hif.tx_seqnum;
178	wdev->hif.tx_seqnum = (wdev->hif.tx_seqnum + 1) % (HIF_COUNTER_MAX + 1);
179
180	data = hif;
181	WARN(len > le16_to_cpu(wdev->hw_caps.size_inp_ch_buf),
182	     "request exceed the chip capability: %zu > %d\n",
183	     len, le16_to_cpu(wdev->hw_caps.size_inp_ch_buf));
184	len = wdev->hwbus_ops->align_size(wdev->hwbus_priv, len);
185	ret = wfx_data_write(wdev, data, len);
186	if (ret)
187		goto end;
188
189	wdev->hif.tx_buffers_used++;
190	_trace_hif_send(hif, wdev->hif.tx_buffers_used);
191end:
192	if (is_encrypted)
193		kfree(data);
194}
195
196static int bh_work_tx(struct wfx_dev *wdev, int max_msg)
197{
198	struct wfx_hif_msg *hif;
199	int i;
200
201	for (i = 0; i < max_msg; i++) {
202		hif = NULL;
203		if (wdev->hif.tx_buffers_used < le16_to_cpu(wdev->hw_caps.num_inp_ch_bufs)) {
204			if (try_wait_for_completion(&wdev->hif_cmd.ready)) {
205				WARN(!mutex_is_locked(&wdev->hif_cmd.lock), "data locking error");
206				hif = wdev->hif_cmd.buf_send;
207			} else {
208				hif = wfx_tx_queues_get(wdev);
209			}
210		}
211		if (!hif)
212			return i;
213		tx_helper(wdev, hif);
214	}
215	return i;
216}
217
218/* In SDIO mode, it is necessary to make an access to a register to acknowledge last received
219 * message. It could be possible to restrict this acknowledge to SDIO mode and only if last
220 * operation was rx.
221 */
222static void ack_sdio_data(struct wfx_dev *wdev)
223{
224	u32 cfg_reg;
225
226	wfx_config_reg_read(wdev, &cfg_reg);
227	if (cfg_reg & 0xFF) {
228		dev_warn(wdev->dev, "chip reports errors: %02x\n", cfg_reg & 0xFF);
229		wfx_config_reg_write_bits(wdev, 0xFF, 0x00);
230	}
231}
232
233static void bh_work(struct work_struct *work)
234{
235	struct wfx_dev *wdev = container_of(work, struct wfx_dev, hif.bh);
236	int stats_req = 0, stats_cnf = 0, stats_ind = 0;
237	bool release_chip = false, last_op_is_rx = false;
238	int num_tx, num_rx;
239
240	device_wakeup(wdev);
241	do {
242		num_tx = bh_work_tx(wdev, 32);
243		stats_req += num_tx;
244		if (num_tx)
245			last_op_is_rx = false;
246		num_rx = bh_work_rx(wdev, 32, &stats_cnf);
247		stats_ind += num_rx;
248		if (num_rx)
249			last_op_is_rx = true;
250	} while (num_rx || num_tx);
251	stats_ind -= stats_cnf;
252
253	if (last_op_is_rx)
254		ack_sdio_data(wdev);
255	if (!wdev->hif.tx_buffers_used && !work_pending(work)) {
256		device_release(wdev);
257		release_chip = true;
258	}
259	_trace_bh_stats(stats_ind, stats_req, stats_cnf, wdev->hif.tx_buffers_used, release_chip);
260}
261
262/* An IRQ from chip did occur */
263void wfx_bh_request_rx(struct wfx_dev *wdev)
264{
265	u32 cur, prev;
266
267	wfx_control_reg_read(wdev, &cur);
268	prev = atomic_xchg(&wdev->hif.ctrl_reg, cur);
269	complete(&wdev->hif.ctrl_ready);
270	queue_work(wdev->bh_wq, &wdev->hif.bh);
271
272	if (!(cur & CTRL_NEXT_LEN_MASK))
273		dev_err(wdev->dev, "unexpected control register value: length field is 0: %04x\n",
274			cur);
275	if (prev != 0)
276		dev_err(wdev->dev, "received IRQ but previous data was not (yet) read: %04x/%04x\n",
277			prev, cur);
278}
279
280/* Driver want to send data */
281void wfx_bh_request_tx(struct wfx_dev *wdev)
282{
283	queue_work(wdev->bh_wq, &wdev->hif.bh);
284}
285
286/* If IRQ is not available, this function allow to manually poll the control register and simulate
287 * an IRQ ahen an event happened.
288 *
289 * Note that the device has a bug: If an IRQ raise while host read control register, the IRQ is
290 * lost. So, use this function carefully (only duing device initialisation).
291 */
292void wfx_bh_poll_irq(struct wfx_dev *wdev)
293{
294	ktime_t now, start;
295	u32 reg;
296
297	WARN(!wdev->poll_irq, "unexpected IRQ polling can mask IRQ");
298	flush_workqueue(wdev->bh_wq);
299	start = ktime_get();
300	for (;;) {
301		wfx_control_reg_read(wdev, &reg);
302		now = ktime_get();
303		if (reg & 0xFFF)
304			break;
305		if (ktime_after(now, ktime_add_ms(start, 1000))) {
306			dev_err(wdev->dev, "time out while polling control register\n");
307			return;
308		}
309		udelay(200);
310	}
311	wfx_bh_request_rx(wdev);
312}
313
314void wfx_bh_register(struct wfx_dev *wdev)
315{
316	INIT_WORK(&wdev->hif.bh, bh_work);
317	init_completion(&wdev->hif.ctrl_ready);
318	init_waitqueue_head(&wdev->hif.tx_buffers_empty);
319}
320
321void wfx_bh_unregister(struct wfx_dev *wdev)
322{
323	flush_work(&wdev->hif.bh);
324}
325