xref: /openbmc/linux/drivers/net/wireless/silabs/wfx/bh.c (revision 4f2c0a4acffbec01079c28f839422e64ddeff004)
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