1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2020-21 Intel Corporation.
4  */
5 
6 #include <linux/nospec.h>
7 
8 #include "iosm_ipc_imem_ops.h"
9 #include "iosm_ipc_mux_codec.h"
10 #include "iosm_ipc_task_queue.h"
11 
12 /* Test the link power state and send a MUX command in blocking mode. */
13 static int ipc_mux_tq_cmd_send(struct iosm_imem *ipc_imem, int arg, void *msg,
14 			       size_t size)
15 {
16 	struct iosm_mux *ipc_mux = ipc_imem->mux;
17 	const struct mux_acb *acb = msg;
18 
19 	skb_queue_tail(&ipc_mux->channel->ul_list, acb->skb);
20 	ipc_imem_ul_send(ipc_mux->imem);
21 
22 	return 0;
23 }
24 
25 static int ipc_mux_acb_send(struct iosm_mux *ipc_mux, bool blocking)
26 {
27 	struct completion *completion = &ipc_mux->channel->ul_sem;
28 	int ret = ipc_task_queue_send_task(ipc_mux->imem, ipc_mux_tq_cmd_send,
29 					   0, &ipc_mux->acb,
30 					   sizeof(ipc_mux->acb), false);
31 	if (ret) {
32 		dev_err(ipc_mux->dev, "unable to send mux command");
33 		return ret;
34 	}
35 
36 	/* if blocking, suspend the app and wait for irq in the flash or
37 	 * crash phase. return false on timeout to indicate failure.
38 	 */
39 	if (blocking) {
40 		u32 wait_time_milliseconds = IPC_MUX_CMD_RUN_DEFAULT_TIMEOUT;
41 
42 		reinit_completion(completion);
43 
44 		if (wait_for_completion_interruptible_timeout
45 		   (completion, msecs_to_jiffies(wait_time_milliseconds)) ==
46 		   0) {
47 			dev_err(ipc_mux->dev, "ch[%d] timeout",
48 				ipc_mux->channel_id);
49 			ipc_uevent_send(ipc_mux->imem->dev, UEVENT_MDM_TIMEOUT);
50 			return -ETIMEDOUT;
51 		}
52 	}
53 
54 	return 0;
55 }
56 
57 /* Prepare mux Command */
58 static struct mux_lite_cmdh *ipc_mux_lite_add_cmd(struct iosm_mux *ipc_mux,
59 						  u32 cmd, struct mux_acb *acb,
60 						  void *param, u32 param_size)
61 {
62 	struct mux_lite_cmdh *cmdh = (struct mux_lite_cmdh *)acb->skb->data;
63 
64 	cmdh->signature = cpu_to_le32(MUX_SIG_CMDH);
65 	cmdh->command_type = cpu_to_le32(cmd);
66 	cmdh->if_id = acb->if_id;
67 
68 	acb->cmd = cmd;
69 
70 	cmdh->cmd_len = cpu_to_le16(offsetof(struct mux_lite_cmdh, param) +
71 				    param_size);
72 	cmdh->transaction_id = cpu_to_le32(ipc_mux->tx_transaction_id++);
73 
74 	if (param)
75 		memcpy(&cmdh->param, param, param_size);
76 
77 	skb_put(acb->skb, le16_to_cpu(cmdh->cmd_len));
78 
79 	return cmdh;
80 }
81 
82 static int ipc_mux_acb_alloc(struct iosm_mux *ipc_mux)
83 {
84 	struct mux_acb *acb = &ipc_mux->acb;
85 	struct sk_buff *skb;
86 	dma_addr_t mapping;
87 
88 	/* Allocate skb memory for the uplink buffer. */
89 	skb = ipc_pcie_alloc_skb(ipc_mux->pcie, MUX_MAX_UL_ACB_BUF_SIZE,
90 				 GFP_ATOMIC, &mapping, DMA_TO_DEVICE, 0);
91 	if (!skb)
92 		return -ENOMEM;
93 
94 	/* Save the skb address. */
95 	acb->skb = skb;
96 
97 	memset(skb->data, 0, MUX_MAX_UL_ACB_BUF_SIZE);
98 
99 	return 0;
100 }
101 
102 int ipc_mux_dl_acb_send_cmds(struct iosm_mux *ipc_mux, u32 cmd_type, u8 if_id,
103 			     u32 transaction_id, union mux_cmd_param *param,
104 			     size_t res_size, bool blocking, bool respond)
105 {
106 	struct mux_acb *acb = &ipc_mux->acb;
107 	struct mux_lite_cmdh *ack_lite;
108 	int ret = 0;
109 
110 	acb->if_id = if_id;
111 	ret = ipc_mux_acb_alloc(ipc_mux);
112 	if (ret)
113 		return ret;
114 
115 	ack_lite = ipc_mux_lite_add_cmd(ipc_mux, cmd_type, acb, param,
116 					res_size);
117 	if (respond)
118 		ack_lite->transaction_id = cpu_to_le32(transaction_id);
119 
120 	ret = ipc_mux_acb_send(ipc_mux, blocking);
121 
122 	return ret;
123 }
124 
125 void ipc_mux_netif_tx_flowctrl(struct mux_session *session, int idx, bool on)
126 {
127 	/* Inform the network interface to start/stop flow ctrl */
128 	ipc_wwan_tx_flowctrl(session->wwan, idx, on);
129 }
130 
131 static int ipc_mux_dl_cmdresps_decode_process(struct iosm_mux *ipc_mux,
132 					      struct mux_lite_cmdh *cmdh)
133 {
134 	struct mux_acb *acb = &ipc_mux->acb;
135 
136 	switch (le32_to_cpu(cmdh->command_type)) {
137 	case MUX_CMD_OPEN_SESSION_RESP:
138 	case MUX_CMD_CLOSE_SESSION_RESP:
139 		/* Resume the control application. */
140 		acb->got_param = cmdh->param;
141 		break;
142 
143 	case MUX_LITE_CMD_FLOW_CTL_ACK:
144 		/* This command type is not expected as response for
145 		 * Aggregation version of the protocol. So return non-zero.
146 		 */
147 		if (ipc_mux->protocol != MUX_LITE)
148 			return -EINVAL;
149 
150 		dev_dbg(ipc_mux->dev, "if %u FLOW_CTL_ACK %u received",
151 			cmdh->if_id, le32_to_cpu(cmdh->transaction_id));
152 		break;
153 
154 	default:
155 		return -EINVAL;
156 	}
157 
158 	acb->wanted_response = MUX_CMD_INVALID;
159 	acb->got_response = le32_to_cpu(cmdh->command_type);
160 	complete(&ipc_mux->channel->ul_sem);
161 
162 	return 0;
163 }
164 
165 static int ipc_mux_dl_dlcmds_decode_process(struct iosm_mux *ipc_mux,
166 					    struct mux_lite_cmdh *cmdh)
167 {
168 	union mux_cmd_param *param = &cmdh->param;
169 	struct mux_session *session;
170 	int new_size;
171 
172 	dev_dbg(ipc_mux->dev, "if_id[%d]: dlcmds decode process %d",
173 		cmdh->if_id, le32_to_cpu(cmdh->command_type));
174 
175 	switch (le32_to_cpu(cmdh->command_type)) {
176 	case MUX_LITE_CMD_FLOW_CTL:
177 
178 		if (cmdh->if_id >= ipc_mux->nr_sessions) {
179 			dev_err(ipc_mux->dev, "if_id [%d] not valid",
180 				cmdh->if_id);
181 			return -EINVAL; /* No session interface id. */
182 		}
183 
184 		session = &ipc_mux->session[cmdh->if_id];
185 
186 		new_size = offsetof(struct mux_lite_cmdh, param) +
187 			   sizeof(param->flow_ctl);
188 		if (param->flow_ctl.mask == cpu_to_le32(0xFFFFFFFF)) {
189 			/* Backward Compatibility */
190 			if (cmdh->cmd_len == cpu_to_le16(new_size))
191 				session->flow_ctl_mask =
192 					le32_to_cpu(param->flow_ctl.mask);
193 			else
194 				session->flow_ctl_mask = ~0;
195 			/* if CP asks for FLOW CTRL Enable
196 			 * then set our internal flow control Tx flag
197 			 * to limit uplink session queueing
198 			 */
199 			session->net_tx_stop = true;
200 			/* Update the stats */
201 			session->flow_ctl_en_cnt++;
202 		} else if (param->flow_ctl.mask == 0) {
203 			/* Just reset the Flow control mask and let
204 			 * mux_flow_ctrl_low_thre_b take control on
205 			 * our internal Tx flag and enabling kernel
206 			 * flow control
207 			 */
208 			/* Backward Compatibility */
209 			if (cmdh->cmd_len == cpu_to_le16(new_size))
210 				session->flow_ctl_mask =
211 					le32_to_cpu(param->flow_ctl.mask);
212 			else
213 				session->flow_ctl_mask = 0;
214 			/* Update the stats */
215 			session->flow_ctl_dis_cnt++;
216 		} else {
217 			break;
218 		}
219 
220 		dev_dbg(ipc_mux->dev, "if[%u] FLOW CTRL 0x%08X", cmdh->if_id,
221 			le32_to_cpu(param->flow_ctl.mask));
222 		break;
223 
224 	case MUX_LITE_CMD_LINK_STATUS_REPORT:
225 		break;
226 
227 	default:
228 		return -EINVAL;
229 	}
230 	return 0;
231 }
232 
233 /* Decode and Send appropriate response to a command block. */
234 static void ipc_mux_dl_cmd_decode(struct iosm_mux *ipc_mux, struct sk_buff *skb)
235 {
236 	struct mux_lite_cmdh *cmdh = (struct mux_lite_cmdh *)skb->data;
237 	__le32 trans_id = cmdh->transaction_id;
238 
239 	if (ipc_mux_dl_cmdresps_decode_process(ipc_mux, cmdh)) {
240 		/* Unable to decode command response indicates the cmd_type
241 		 * may be a command instead of response. So try to decoding it.
242 		 */
243 		if (!ipc_mux_dl_dlcmds_decode_process(ipc_mux, cmdh)) {
244 			/* Decoded command may need a response. Give the
245 			 * response according to the command type.
246 			 */
247 			union mux_cmd_param *mux_cmd = NULL;
248 			size_t size = 0;
249 			u32 cmd = MUX_LITE_CMD_LINK_STATUS_REPORT_RESP;
250 
251 			if (cmdh->command_type ==
252 			    cpu_to_le32(MUX_LITE_CMD_LINK_STATUS_REPORT)) {
253 				mux_cmd = &cmdh->param;
254 				mux_cmd->link_status_resp.response =
255 					cpu_to_le32(MUX_CMD_RESP_SUCCESS);
256 				/* response field is u32 */
257 				size = sizeof(u32);
258 			} else if (cmdh->command_type ==
259 				   cpu_to_le32(MUX_LITE_CMD_FLOW_CTL)) {
260 				cmd = MUX_LITE_CMD_FLOW_CTL_ACK;
261 			} else {
262 				return;
263 			}
264 
265 			if (ipc_mux_dl_acb_send_cmds(ipc_mux, cmd, cmdh->if_id,
266 						     le32_to_cpu(trans_id),
267 						     mux_cmd, size, false,
268 						     true))
269 				dev_err(ipc_mux->dev,
270 					"if_id %d: cmd send failed",
271 					cmdh->if_id);
272 		}
273 	}
274 }
275 
276 /* Pass the DL packet to the netif layer. */
277 static int ipc_mux_net_receive(struct iosm_mux *ipc_mux, int if_id,
278 			       struct iosm_wwan *wwan, u32 offset,
279 			       u8 service_class, struct sk_buff *skb)
280 {
281 	struct sk_buff *dest_skb = skb_clone(skb, GFP_ATOMIC);
282 
283 	if (!dest_skb)
284 		return -ENOMEM;
285 
286 	skb_pull(dest_skb, offset);
287 	skb_set_tail_pointer(dest_skb, dest_skb->len);
288 	/* Pass the packet to the netif layer. */
289 	dest_skb->priority = service_class;
290 
291 	return ipc_wwan_receive(wwan, dest_skb, false, if_id);
292 }
293 
294 /* Decode Flow Credit Table in the block */
295 static void ipc_mux_dl_fcth_decode(struct iosm_mux *ipc_mux,
296 				   unsigned char *block)
297 {
298 	struct ipc_mem_lite_gen_tbl *fct = (struct ipc_mem_lite_gen_tbl *)block;
299 	struct iosm_wwan *wwan;
300 	int ul_credits;
301 	int if_id;
302 
303 	if (fct->vfl_length != sizeof(fct->vfl.nr_of_bytes)) {
304 		dev_err(ipc_mux->dev, "unexpected FCT length: %d",
305 			fct->vfl_length);
306 		return;
307 	}
308 
309 	if_id = fct->if_id;
310 	if (if_id >= ipc_mux->nr_sessions) {
311 		dev_err(ipc_mux->dev, "not supported if_id: %d", if_id);
312 		return;
313 	}
314 
315 	/* Is the session active ? */
316 	if_id = array_index_nospec(if_id, ipc_mux->nr_sessions);
317 	wwan = ipc_mux->session[if_id].wwan;
318 	if (!wwan) {
319 		dev_err(ipc_mux->dev, "session Net ID is NULL");
320 		return;
321 	}
322 
323 	ul_credits = fct->vfl.nr_of_bytes;
324 
325 	dev_dbg(ipc_mux->dev, "Flow_Credit:: if_id[%d] Old: %d Grants: %d",
326 		if_id, ipc_mux->session[if_id].ul_flow_credits, ul_credits);
327 
328 	/* Update the Flow Credit information from ADB */
329 	ipc_mux->session[if_id].ul_flow_credits += ul_credits;
330 
331 	/* Check whether the TX can be started */
332 	if (ipc_mux->session[if_id].ul_flow_credits > 0) {
333 		ipc_mux->session[if_id].net_tx_stop = false;
334 		ipc_mux_netif_tx_flowctrl(&ipc_mux->session[if_id],
335 					  ipc_mux->session[if_id].if_id, false);
336 	}
337 }
338 
339 /* Decode non-aggregated datagram */
340 static void ipc_mux_dl_adgh_decode(struct iosm_mux *ipc_mux,
341 				   struct sk_buff *skb)
342 {
343 	u32 pad_len, packet_offset;
344 	struct iosm_wwan *wwan;
345 	struct mux_adgh *adgh;
346 	u8 *block = skb->data;
347 	int rc = 0;
348 	u8 if_id;
349 
350 	adgh = (struct mux_adgh *)block;
351 
352 	if (adgh->signature != cpu_to_le32(MUX_SIG_ADGH)) {
353 		dev_err(ipc_mux->dev, "invalid ADGH signature received");
354 		return;
355 	}
356 
357 	if_id = adgh->if_id;
358 	if (if_id >= ipc_mux->nr_sessions) {
359 		dev_err(ipc_mux->dev, "invalid if_id while decoding %d", if_id);
360 		return;
361 	}
362 
363 	/* Is the session active ? */
364 	if_id = array_index_nospec(if_id, ipc_mux->nr_sessions);
365 	wwan = ipc_mux->session[if_id].wwan;
366 	if (!wwan) {
367 		dev_err(ipc_mux->dev, "session Net ID is NULL");
368 		return;
369 	}
370 
371 	/* Store the pad len for the corresponding session
372 	 * Pad bytes as negotiated in the open session less the header size
373 	 * (see session management chapter for details).
374 	 * If resulting padding is zero or less, the additional head padding is
375 	 * omitted. For e.g., if HEAD_PAD_LEN = 16 or less, this field is
376 	 * omitted if HEAD_PAD_LEN = 20, then this field will have 4 bytes
377 	 * set to zero
378 	 */
379 	pad_len =
380 		ipc_mux->session[if_id].dl_head_pad_len - IPC_MEM_DL_ETH_OFFSET;
381 	packet_offset = sizeof(*adgh) + pad_len;
382 
383 	if_id += ipc_mux->wwan_q_offset;
384 
385 	/* Pass the packet to the netif layer */
386 	rc = ipc_mux_net_receive(ipc_mux, if_id, wwan, packet_offset,
387 				 adgh->service_class, skb);
388 	if (rc) {
389 		dev_err(ipc_mux->dev, "mux adgh decoding error");
390 		return;
391 	}
392 	ipc_mux->session[if_id].flush = 1;
393 }
394 
395 void ipc_mux_dl_decode(struct iosm_mux *ipc_mux, struct sk_buff *skb)
396 {
397 	u32 signature;
398 
399 	if (!skb->data)
400 		return;
401 
402 	/* Decode the MUX header type. */
403 	signature = le32_to_cpup((__le32 *)skb->data);
404 
405 	switch (signature) {
406 	case MUX_SIG_ADGH:
407 		ipc_mux_dl_adgh_decode(ipc_mux, skb);
408 		break;
409 
410 	case MUX_SIG_FCTH:
411 		ipc_mux_dl_fcth_decode(ipc_mux, skb->data);
412 		break;
413 
414 	case MUX_SIG_CMDH:
415 		ipc_mux_dl_cmd_decode(ipc_mux, skb);
416 		break;
417 
418 	default:
419 		dev_err(ipc_mux->dev, "invalid ABH signature");
420 	}
421 
422 	ipc_pcie_kfree_skb(ipc_mux->pcie, skb);
423 }
424 
425 static int ipc_mux_ul_skb_alloc(struct iosm_mux *ipc_mux,
426 				struct mux_adb *ul_adb, u32 type)
427 {
428 	/* Take the first element of the free list. */
429 	struct sk_buff *skb = skb_dequeue(&ul_adb->free_list);
430 	int qlt_size;
431 
432 	if (!skb)
433 		return -EBUSY; /* Wait for a free ADB skb. */
434 
435 	/* Mark it as UL ADB to select the right free operation. */
436 	IPC_CB(skb)->op_type = (u8)UL_MUX_OP_ADB;
437 
438 	switch (type) {
439 	case MUX_SIG_ADGH:
440 		/* Save the ADB memory settings. */
441 		ul_adb->dest_skb = skb;
442 		ul_adb->buf = skb->data;
443 		ul_adb->size = IPC_MEM_MAX_DL_MUX_LITE_BUF_SIZE;
444 		/* reset statistic counter */
445 		ul_adb->if_cnt = 0;
446 		ul_adb->payload_size = 0;
447 		ul_adb->dg_cnt_total = 0;
448 
449 		ul_adb->adgh = (struct mux_adgh *)skb->data;
450 		memset(ul_adb->adgh, 0, sizeof(struct mux_adgh));
451 		break;
452 
453 	case MUX_SIG_QLTH:
454 		qlt_size = offsetof(struct ipc_mem_lite_gen_tbl, vfl) +
455 			   (MUX_QUEUE_LEVEL * sizeof(struct mux_lite_vfl));
456 
457 		if (qlt_size > IPC_MEM_MAX_DL_MUX_LITE_BUF_SIZE) {
458 			dev_err(ipc_mux->dev,
459 				"can't support. QLT size:%d SKB size: %d",
460 				qlt_size, IPC_MEM_MAX_DL_MUX_LITE_BUF_SIZE);
461 			return -ERANGE;
462 		}
463 
464 		ul_adb->qlth_skb = skb;
465 		memset((ul_adb->qlth_skb)->data, 0, qlt_size);
466 		skb_put(skb, qlt_size);
467 		break;
468 	}
469 
470 	return 0;
471 }
472 
473 static void ipc_mux_ul_adgh_finish(struct iosm_mux *ipc_mux)
474 {
475 	struct mux_adb *ul_adb = &ipc_mux->ul_adb;
476 	u16 adgh_len;
477 	long long bytes;
478 	char *str;
479 
480 	if (!ul_adb->dest_skb) {
481 		dev_err(ipc_mux->dev, "no dest skb");
482 		return;
483 	}
484 
485 	adgh_len = le16_to_cpu(ul_adb->adgh->length);
486 	skb_put(ul_adb->dest_skb, adgh_len);
487 	skb_queue_tail(&ipc_mux->channel->ul_list, ul_adb->dest_skb);
488 	ul_adb->dest_skb = NULL;
489 
490 	if (ipc_mux->ul_flow == MUX_UL_ON_CREDITS) {
491 		struct mux_session *session;
492 
493 		session = &ipc_mux->session[ul_adb->adgh->if_id];
494 		str = "available_credits";
495 		bytes = (long long)session->ul_flow_credits;
496 
497 	} else {
498 		str = "pend_bytes";
499 		bytes = ipc_mux->ul_data_pend_bytes;
500 		ipc_mux->ul_data_pend_bytes = ipc_mux->ul_data_pend_bytes +
501 					      adgh_len;
502 	}
503 
504 	dev_dbg(ipc_mux->dev, "UL ADGH: size=%u, if_id=%d, payload=%d, %s=%lld",
505 		adgh_len, ul_adb->adgh->if_id, ul_adb->payload_size,
506 		str, bytes);
507 }
508 
509 /* Allocates an ADB from the free list and initializes it with ADBH  */
510 static bool ipc_mux_ul_adb_allocate(struct iosm_mux *ipc_mux,
511 				    struct mux_adb *adb, int *size_needed,
512 				    u32 type)
513 {
514 	bool ret_val = false;
515 	int status;
516 
517 	if (!adb->dest_skb) {
518 		/* Allocate memory for the ADB including of the
519 		 * datagram table header.
520 		 */
521 		status = ipc_mux_ul_skb_alloc(ipc_mux, adb, type);
522 		if (status)
523 			/* Is a pending ADB available ? */
524 			ret_val = true; /* None. */
525 
526 		/* Update size need to zero only for new ADB memory */
527 		*size_needed = 0;
528 	}
529 
530 	return ret_val;
531 }
532 
533 /* Informs the network stack to stop sending further packets for all opened
534  * sessions
535  */
536 static void ipc_mux_stop_tx_for_all_sessions(struct iosm_mux *ipc_mux)
537 {
538 	struct mux_session *session;
539 	int idx;
540 
541 	for (idx = 0; idx < ipc_mux->nr_sessions; idx++) {
542 		session = &ipc_mux->session[idx];
543 
544 		if (!session->wwan)
545 			continue;
546 
547 		session->net_tx_stop = true;
548 	}
549 }
550 
551 /* Sends Queue Level Table of all opened sessions */
552 static bool ipc_mux_lite_send_qlt(struct iosm_mux *ipc_mux)
553 {
554 	struct ipc_mem_lite_gen_tbl *qlt;
555 	struct mux_session *session;
556 	bool qlt_updated = false;
557 	int i;
558 	int qlt_size;
559 
560 	if (!ipc_mux->initialized || ipc_mux->state != MUX_S_ACTIVE)
561 		return qlt_updated;
562 
563 	qlt_size = offsetof(struct ipc_mem_lite_gen_tbl, vfl) +
564 		   MUX_QUEUE_LEVEL * sizeof(struct mux_lite_vfl);
565 
566 	for (i = 0; i < ipc_mux->nr_sessions; i++) {
567 		session = &ipc_mux->session[i];
568 
569 		if (!session->wwan || session->flow_ctl_mask)
570 			continue;
571 
572 		if (ipc_mux_ul_skb_alloc(ipc_mux, &ipc_mux->ul_adb,
573 					 MUX_SIG_QLTH)) {
574 			dev_err(ipc_mux->dev,
575 				"no reserved mem to send QLT of if_id: %d", i);
576 			break;
577 		}
578 
579 		/* Prepare QLT */
580 		qlt = (struct ipc_mem_lite_gen_tbl *)(ipc_mux->ul_adb.qlth_skb)
581 			      ->data;
582 		qlt->signature = cpu_to_le32(MUX_SIG_QLTH);
583 		qlt->length = cpu_to_le16(qlt_size);
584 		qlt->if_id = i;
585 		qlt->vfl_length = MUX_QUEUE_LEVEL * sizeof(struct mux_lite_vfl);
586 		qlt->reserved[0] = 0;
587 		qlt->reserved[1] = 0;
588 
589 		qlt->vfl.nr_of_bytes = session->ul_list.qlen;
590 
591 		/* Add QLT to the transfer list. */
592 		skb_queue_tail(&ipc_mux->channel->ul_list,
593 			       ipc_mux->ul_adb.qlth_skb);
594 
595 		qlt_updated = true;
596 		ipc_mux->ul_adb.qlth_skb = NULL;
597 	}
598 
599 	if (qlt_updated)
600 		/* Updates the TDs with ul_list */
601 		(void)ipc_imem_ul_write_td(ipc_mux->imem);
602 
603 	return qlt_updated;
604 }
605 
606 /* Checks the available credits for the specified session and returns
607  * number of packets for which credits are available.
608  */
609 static int ipc_mux_ul_bytes_credits_check(struct iosm_mux *ipc_mux,
610 					  struct mux_session *session,
611 					  struct sk_buff_head *ul_list,
612 					  int max_nr_of_pkts)
613 {
614 	int pkts_to_send = 0;
615 	struct sk_buff *skb;
616 	int credits = 0;
617 
618 	if (ipc_mux->ul_flow == MUX_UL_ON_CREDITS) {
619 		credits = session->ul_flow_credits;
620 		if (credits <= 0) {
621 			dev_dbg(ipc_mux->dev,
622 				"FC::if_id[%d] Insuff.Credits/Qlen:%d/%u",
623 				session->if_id, session->ul_flow_credits,
624 				session->ul_list.qlen); /* nr_of_bytes */
625 			return 0;
626 		}
627 	} else {
628 		credits = IPC_MEM_MUX_UL_FLOWCTRL_HIGH_B -
629 			  ipc_mux->ul_data_pend_bytes;
630 		if (credits <= 0) {
631 			ipc_mux_stop_tx_for_all_sessions(ipc_mux);
632 
633 			dev_dbg(ipc_mux->dev,
634 				"if_id[%d] encod. fail Bytes: %llu, thresh: %d",
635 				session->if_id, ipc_mux->ul_data_pend_bytes,
636 				IPC_MEM_MUX_UL_FLOWCTRL_HIGH_B);
637 			return 0;
638 		}
639 	}
640 
641 	/* Check if there are enough credits/bytes available to send the
642 	 * requested max_nr_of_pkts. Otherwise restrict the nr_of_pkts
643 	 * depending on available credits.
644 	 */
645 	skb_queue_walk(ul_list, skb)
646 	{
647 		if (!(credits >= skb->len && pkts_to_send < max_nr_of_pkts))
648 			break;
649 		credits -= skb->len;
650 		pkts_to_send++;
651 	}
652 
653 	return pkts_to_send;
654 }
655 
656 /* Encode the UL IP packet according to Lite spec. */
657 static int ipc_mux_ul_adgh_encode(struct iosm_mux *ipc_mux, int session_id,
658 				  struct mux_session *session,
659 				  struct sk_buff_head *ul_list,
660 				  struct mux_adb *adb, int nr_of_pkts)
661 {
662 	int offset = sizeof(struct mux_adgh);
663 	int adb_updated = -EINVAL;
664 	struct sk_buff *src_skb;
665 	int aligned_size = 0;
666 	int nr_of_skb = 0;
667 	u32 pad_len = 0;
668 
669 	/* Re-calculate the number of packets depending on number of bytes to be
670 	 * processed/available credits.
671 	 */
672 	nr_of_pkts = ipc_mux_ul_bytes_credits_check(ipc_mux, session, ul_list,
673 						    nr_of_pkts);
674 
675 	/* If calculated nr_of_pkts from available credits is <= 0
676 	 * then nothing to do.
677 	 */
678 	if (nr_of_pkts <= 0)
679 		return 0;
680 
681 	/* Read configured UL head_pad_length for session.*/
682 	if (session->ul_head_pad_len > IPC_MEM_DL_ETH_OFFSET)
683 		pad_len = session->ul_head_pad_len - IPC_MEM_DL_ETH_OFFSET;
684 
685 	/* Process all pending UL packets for this session
686 	 * depending on the allocated datagram table size.
687 	 */
688 	while (nr_of_pkts > 0) {
689 		/* get destination skb allocated */
690 		if (ipc_mux_ul_adb_allocate(ipc_mux, adb, &ipc_mux->size_needed,
691 					    MUX_SIG_ADGH)) {
692 			dev_err(ipc_mux->dev, "no reserved memory for ADGH");
693 			return -ENOMEM;
694 		}
695 
696 		/* Peek at the head of the list. */
697 		src_skb = skb_peek(ul_list);
698 		if (!src_skb) {
699 			dev_err(ipc_mux->dev,
700 				"skb peek return NULL with count : %d",
701 				nr_of_pkts);
702 			break;
703 		}
704 
705 		/* Calculate the memory value. */
706 		aligned_size = ALIGN((pad_len + src_skb->len), 4);
707 
708 		ipc_mux->size_needed = sizeof(struct mux_adgh) + aligned_size;
709 
710 		if (ipc_mux->size_needed > adb->size) {
711 			dev_dbg(ipc_mux->dev, "size needed %d, adgh size %d",
712 				ipc_mux->size_needed, adb->size);
713 			/* Return 1 if any IP packet is added to the transfer
714 			 * list.
715 			 */
716 			return nr_of_skb ? 1 : 0;
717 		}
718 
719 		/* Add buffer (without head padding to next pending transfer) */
720 		memcpy(adb->buf + offset + pad_len, src_skb->data,
721 		       src_skb->len);
722 
723 		adb->adgh->signature = cpu_to_le32(MUX_SIG_ADGH);
724 		adb->adgh->if_id = session_id;
725 		adb->adgh->length =
726 			cpu_to_le16(sizeof(struct mux_adgh) + pad_len +
727 				    src_skb->len);
728 		adb->adgh->service_class = src_skb->priority;
729 		adb->adgh->next_count = --nr_of_pkts;
730 		adb->dg_cnt_total++;
731 		adb->payload_size += src_skb->len;
732 
733 		if (ipc_mux->ul_flow == MUX_UL_ON_CREDITS)
734 			/* Decrement the credit value as we are processing the
735 			 * datagram from the UL list.
736 			 */
737 			session->ul_flow_credits -= src_skb->len;
738 
739 		/* Remove the processed elements and free it. */
740 		src_skb = skb_dequeue(ul_list);
741 		dev_kfree_skb(src_skb);
742 		nr_of_skb++;
743 
744 		ipc_mux_ul_adgh_finish(ipc_mux);
745 	}
746 
747 	if (nr_of_skb) {
748 		/* Send QLT info to modem if pending bytes > high watermark
749 		 * in case of mux lite
750 		 */
751 		if (ipc_mux->ul_flow == MUX_UL_ON_CREDITS ||
752 		    ipc_mux->ul_data_pend_bytes >=
753 			    IPC_MEM_MUX_UL_FLOWCTRL_LOW_B)
754 			adb_updated = ipc_mux_lite_send_qlt(ipc_mux);
755 		else
756 			adb_updated = 1;
757 
758 		/* Updates the TDs with ul_list */
759 		(void)ipc_imem_ul_write_td(ipc_mux->imem);
760 	}
761 
762 	return adb_updated;
763 }
764 
765 bool ipc_mux_ul_data_encode(struct iosm_mux *ipc_mux)
766 {
767 	struct sk_buff_head *ul_list;
768 	struct mux_session *session;
769 	int updated = 0;
770 	int session_id;
771 	int dg_n;
772 	int i;
773 
774 	if (!ipc_mux || ipc_mux->state != MUX_S_ACTIVE ||
775 	    ipc_mux->adb_prep_ongoing)
776 		return false;
777 
778 	ipc_mux->adb_prep_ongoing = true;
779 
780 	for (i = 0; i < ipc_mux->nr_sessions; i++) {
781 		session_id = ipc_mux->rr_next_session;
782 		session = &ipc_mux->session[session_id];
783 
784 		/* Go to next handle rr_next_session overflow */
785 		ipc_mux->rr_next_session++;
786 		if (ipc_mux->rr_next_session >= ipc_mux->nr_sessions)
787 			ipc_mux->rr_next_session = 0;
788 
789 		if (!session->wwan || session->flow_ctl_mask ||
790 		    session->net_tx_stop)
791 			continue;
792 
793 		ul_list = &session->ul_list;
794 
795 		/* Is something pending in UL and flow ctrl off */
796 		dg_n = skb_queue_len(ul_list);
797 		if (dg_n > MUX_MAX_UL_DG_ENTRIES)
798 			dg_n = MUX_MAX_UL_DG_ENTRIES;
799 
800 		if (dg_n == 0)
801 			/* Nothing to do for ipc_mux session
802 			 * -> try next session id.
803 			 */
804 			continue;
805 
806 		updated = ipc_mux_ul_adgh_encode(ipc_mux, session_id, session,
807 						 ul_list, &ipc_mux->ul_adb,
808 						 dg_n);
809 	}
810 
811 	ipc_mux->adb_prep_ongoing = false;
812 	return updated == 1;
813 }
814 
815 void ipc_mux_ul_encoded_process(struct iosm_mux *ipc_mux, struct sk_buff *skb)
816 {
817 	struct mux_adgh *adgh;
818 	u16 adgh_len;
819 
820 	adgh = (struct mux_adgh *)skb->data;
821 	adgh_len = le16_to_cpu(adgh->length);
822 
823 	if (adgh->signature == cpu_to_le32(MUX_SIG_ADGH) &&
824 	    ipc_mux->ul_flow == MUX_UL)
825 		ipc_mux->ul_data_pend_bytes = ipc_mux->ul_data_pend_bytes -
826 					      adgh_len;
827 
828 	if (ipc_mux->ul_flow == MUX_UL)
829 		dev_dbg(ipc_mux->dev, "ul_data_pend_bytes: %lld",
830 			ipc_mux->ul_data_pend_bytes);
831 
832 	/* Reset the skb settings. */
833 	skb->tail = 0;
834 	skb->len = 0;
835 
836 	/* Add the consumed ADB to the free list. */
837 	skb_queue_tail((&ipc_mux->ul_adb.free_list), skb);
838 }
839 
840 /* Start the NETIF uplink send transfer in MUX mode. */
841 static int ipc_mux_tq_ul_trigger_encode(struct iosm_imem *ipc_imem, int arg,
842 					void *msg, size_t size)
843 {
844 	struct iosm_mux *ipc_mux = ipc_imem->mux;
845 	bool ul_data_pend = false;
846 
847 	/* Add session UL data to a ADB and ADGH */
848 	ul_data_pend = ipc_mux_ul_data_encode(ipc_mux);
849 	if (ul_data_pend)
850 		/* Delay the doorbell irq */
851 		ipc_imem_td_update_timer_start(ipc_mux->imem);
852 
853 	/* reset the debounce flag */
854 	ipc_mux->ev_mux_net_transmit_pending = false;
855 
856 	return 0;
857 }
858 
859 int ipc_mux_ul_trigger_encode(struct iosm_mux *ipc_mux, int if_id,
860 			      struct sk_buff *skb)
861 {
862 	struct mux_session *session = &ipc_mux->session[if_id];
863 	int ret = -EINVAL;
864 
865 	if (ipc_mux->channel &&
866 	    ipc_mux->channel->state != IMEM_CHANNEL_ACTIVE) {
867 		dev_err(ipc_mux->dev,
868 			"channel state is not IMEM_CHANNEL_ACTIVE");
869 		goto out;
870 	}
871 
872 	if (!session->wwan) {
873 		dev_err(ipc_mux->dev, "session net ID is NULL");
874 		ret = -EFAULT;
875 		goto out;
876 	}
877 
878 	/* Session is under flow control.
879 	 * Check if packet can be queued in session list, if not
880 	 * suspend net tx
881 	 */
882 	if (skb_queue_len(&session->ul_list) >=
883 	    (session->net_tx_stop ?
884 		     IPC_MEM_MUX_UL_SESS_FCON_THRESHOLD :
885 		     (IPC_MEM_MUX_UL_SESS_FCON_THRESHOLD *
886 		      IPC_MEM_MUX_UL_SESS_FCOFF_THRESHOLD_FACTOR))) {
887 		ipc_mux_netif_tx_flowctrl(session, session->if_id, true);
888 		ret = -EBUSY;
889 		goto out;
890 	}
891 
892 	/* Add skb to the uplink skb accumulator. */
893 	skb_queue_tail(&session->ul_list, skb);
894 
895 	/* Inform the IPC kthread to pass uplink IP packets to CP. */
896 	if (!ipc_mux->ev_mux_net_transmit_pending) {
897 		ipc_mux->ev_mux_net_transmit_pending = true;
898 		ret = ipc_task_queue_send_task(ipc_mux->imem,
899 					       ipc_mux_tq_ul_trigger_encode, 0,
900 					       NULL, 0, false);
901 		if (ret)
902 			goto out;
903 	}
904 	dev_dbg(ipc_mux->dev, "mux ul if[%d] qlen=%d/%u, len=%d/%d, prio=%d",
905 		if_id, skb_queue_len(&session->ul_list), session->ul_list.qlen,
906 		skb->len, skb->truesize, skb->priority);
907 	ret = 0;
908 out:
909 	return ret;
910 }
911