xref: /openbmc/linux/drivers/net/wireless/silabs/wfx/bh.c (revision eeff214d)
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 
device_wakeup(struct wfx_dev * wdev)18 static 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 
device_release(struct wfx_dev * wdev)55 static 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 
rx_helper(struct wfx_dev * wdev,size_t read_len,int * is_cnf)63 static 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 
127 err:
128 	if (skb)
129 		dev_kfree_skb(skb);
130 	return -EIO;
131 }
132 
bh_work_rx(struct wfx_dev * wdev,int max_msg,int * num_cnf)133 static 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 
tx_helper(struct wfx_dev * wdev,struct wfx_hif_msg * hif)168 static 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);
191 end:
192 	if (is_encrypted)
193 		kfree(data);
194 }
195 
bh_work_tx(struct wfx_dev * wdev,int max_msg)196 static 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  */
ack_sdio_data(struct wfx_dev * wdev)222 static 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 
bh_work(struct work_struct * work)233 static 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 */
wfx_bh_request_rx(struct wfx_dev * wdev)263 void 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 */
wfx_bh_request_tx(struct wfx_dev * wdev)281 void 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  */
wfx_bh_poll_irq(struct wfx_dev * wdev)292 void 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 
wfx_bh_register(struct wfx_dev * wdev)314 void 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 
wfx_bh_unregister(struct wfx_dev * wdev)321 void wfx_bh_unregister(struct wfx_dev *wdev)
322 {
323 	flush_work(&wdev->hif.bh);
324 }
325