1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2020-21 Intel Corporation.
4  */
5 
6 #include <linux/delay.h>
7 
8 #include "iosm_ipc_chnl_cfg.h"
9 #include "iosm_ipc_devlink.h"
10 #include "iosm_ipc_imem.h"
11 #include "iosm_ipc_imem_ops.h"
12 #include "iosm_ipc_port.h"
13 #include "iosm_ipc_task_queue.h"
14 
15 /* Open a packet data online channel between the network layer and CP. */
16 int ipc_imem_sys_wwan_open(struct iosm_imem *ipc_imem, int if_id)
17 {
18 	dev_dbg(ipc_imem->dev, "%s if id: %d",
19 		ipc_imem_phase_get_string(ipc_imem->phase), if_id);
20 
21 	/* The network interface is only supported in the runtime phase. */
22 	if (ipc_imem_phase_update(ipc_imem) != IPC_P_RUN) {
23 		dev_err(ipc_imem->dev, "net:%d : refused phase %s", if_id,
24 			ipc_imem_phase_get_string(ipc_imem->phase));
25 		return -EIO;
26 	}
27 
28 	return ipc_mux_open_session(ipc_imem->mux, if_id);
29 }
30 
31 /* Release a net link to CP. */
32 void ipc_imem_sys_wwan_close(struct iosm_imem *ipc_imem, int if_id,
33 			     int channel_id)
34 {
35 	if (ipc_imem->mux && if_id >= IP_MUX_SESSION_START &&
36 	    if_id <= IP_MUX_SESSION_END)
37 		ipc_mux_close_session(ipc_imem->mux, if_id);
38 }
39 
40 /* Tasklet call to do uplink transfer. */
41 static int ipc_imem_tq_cdev_write(struct iosm_imem *ipc_imem, int arg,
42 				  void *msg, size_t size)
43 {
44 	ipc_imem_ul_send(ipc_imem);
45 
46 	return 0;
47 }
48 
49 /* Through tasklet to do sio write. */
50 static int ipc_imem_call_cdev_write(struct iosm_imem *ipc_imem)
51 {
52 	return ipc_task_queue_send_task(ipc_imem, ipc_imem_tq_cdev_write, 0,
53 					NULL, 0, false);
54 }
55 
56 /* Function for transfer UL data */
57 int ipc_imem_sys_wwan_transmit(struct iosm_imem *ipc_imem,
58 			       int if_id, int channel_id, struct sk_buff *skb)
59 {
60 	int ret = -EINVAL;
61 
62 	if (!ipc_imem || channel_id < 0)
63 		goto out;
64 
65 	/* Is CP Running? */
66 	if (ipc_imem->phase != IPC_P_RUN) {
67 		dev_dbg(ipc_imem->dev, "phase %s transmit",
68 			ipc_imem_phase_get_string(ipc_imem->phase));
69 		ret = -EIO;
70 		goto out;
71 	}
72 
73 	/* Route the UL packet through IP MUX Layer */
74 	ret = ipc_mux_ul_trigger_encode(ipc_imem->mux, if_id, skb);
75 out:
76 	return ret;
77 }
78 
79 /* Initialize wwan channel */
80 void ipc_imem_wwan_channel_init(struct iosm_imem *ipc_imem,
81 				enum ipc_mux_protocol mux_type)
82 {
83 	struct ipc_chnl_cfg chnl_cfg = { 0 };
84 
85 	ipc_imem->cp_version = ipc_mmio_get_cp_version(ipc_imem->mmio);
86 
87 	/* If modem version is invalid (0xffffffff), do not initialize WWAN. */
88 	if (ipc_imem->cp_version == -1) {
89 		dev_err(ipc_imem->dev, "invalid CP version");
90 		return;
91 	}
92 
93 	ipc_chnl_cfg_get(&chnl_cfg, ipc_imem->nr_of_channels);
94 
95 	if (ipc_imem->mmio->mux_protocol == MUX_AGGREGATION &&
96 	    ipc_imem->nr_of_channels == IPC_MEM_IP_CHL_ID_0) {
97 		chnl_cfg.ul_nr_of_entries = IPC_MEM_MAX_TDS_MUX_AGGR_UL;
98 		chnl_cfg.dl_nr_of_entries = IPC_MEM_MAX_TDS_MUX_AGGR_DL;
99 		chnl_cfg.dl_buf_size = IPC_MEM_MAX_ADB_BUF_SIZE;
100 	}
101 
102 	ipc_imem_channel_init(ipc_imem, IPC_CTYPE_WWAN, chnl_cfg,
103 			      IRQ_MOD_OFF);
104 
105 	/* WWAN registration. */
106 	ipc_imem->wwan = ipc_wwan_init(ipc_imem, ipc_imem->dev);
107 	if (!ipc_imem->wwan)
108 		dev_err(ipc_imem->dev,
109 			"failed to register the ipc_wwan interfaces");
110 }
111 
112 /* Map SKB to DMA for transfer */
113 static int ipc_imem_map_skb_to_dma(struct iosm_imem *ipc_imem,
114 				   struct sk_buff *skb)
115 {
116 	struct iosm_pcie *ipc_pcie = ipc_imem->pcie;
117 	char *buf = skb->data;
118 	int len = skb->len;
119 	dma_addr_t mapping;
120 	int ret;
121 
122 	ret = ipc_pcie_addr_map(ipc_pcie, buf, len, &mapping, DMA_TO_DEVICE);
123 
124 	if (ret)
125 		goto err;
126 
127 	BUILD_BUG_ON(sizeof(*IPC_CB(skb)) > sizeof(skb->cb));
128 
129 	IPC_CB(skb)->mapping = mapping;
130 	IPC_CB(skb)->direction = DMA_TO_DEVICE;
131 	IPC_CB(skb)->len = len;
132 	IPC_CB(skb)->op_type = (u8)UL_DEFAULT;
133 
134 err:
135 	return ret;
136 }
137 
138 /* return true if channel is ready for use */
139 static bool ipc_imem_is_channel_active(struct iosm_imem *ipc_imem,
140 				       struct ipc_mem_channel *channel)
141 {
142 	enum ipc_phase phase;
143 
144 	/* Update the current operation phase. */
145 	phase = ipc_imem->phase;
146 
147 	/* Select the operation depending on the execution stage. */
148 	switch (phase) {
149 	case IPC_P_RUN:
150 	case IPC_P_PSI:
151 	case IPC_P_EBL:
152 		break;
153 
154 	case IPC_P_ROM:
155 		/* Prepare the PSI image for the CP ROM driver and
156 		 * suspend the flash app.
157 		 */
158 		if (channel->state != IMEM_CHANNEL_RESERVED) {
159 			dev_err(ipc_imem->dev,
160 				"ch[%d]:invalid channel state %d,expected %d",
161 				channel->channel_id, channel->state,
162 				IMEM_CHANNEL_RESERVED);
163 			goto channel_unavailable;
164 		}
165 		goto channel_available;
166 
167 	default:
168 		/* Ignore uplink actions in all other phases. */
169 		dev_err(ipc_imem->dev, "ch[%d]: confused phase %d",
170 			channel->channel_id, phase);
171 		goto channel_unavailable;
172 	}
173 	/* Check the full availability of the channel. */
174 	if (channel->state != IMEM_CHANNEL_ACTIVE) {
175 		dev_err(ipc_imem->dev, "ch[%d]: confused channel state %d",
176 			channel->channel_id, channel->state);
177 		goto channel_unavailable;
178 	}
179 
180 channel_available:
181 	return true;
182 
183 channel_unavailable:
184 	return false;
185 }
186 
187 /**
188  * ipc_imem_sys_port_close - Release a sio link to CP.
189  * @ipc_imem:          Imem instance.
190  * @channel:           Channel instance.
191  */
192 void ipc_imem_sys_port_close(struct iosm_imem *ipc_imem,
193 			     struct ipc_mem_channel *channel)
194 {
195 	enum ipc_phase curr_phase;
196 	int status = 0;
197 	u32 tail = 0;
198 
199 	curr_phase = ipc_imem->phase;
200 
201 	/* If current phase is IPC_P_OFF or SIO ID is -ve then
202 	 * channel is already freed. Nothing to do.
203 	 */
204 	if (curr_phase == IPC_P_OFF) {
205 		dev_err(ipc_imem->dev,
206 			"nothing to do. Current Phase: %s",
207 			ipc_imem_phase_get_string(curr_phase));
208 		return;
209 	}
210 
211 	if (channel->state == IMEM_CHANNEL_FREE) {
212 		dev_err(ipc_imem->dev, "ch[%d]: invalid channel state %d",
213 			channel->channel_id, channel->state);
214 		return;
215 	}
216 
217 	/* If there are any pending TDs then wait for Timeout/Completion before
218 	 * closing pipe.
219 	 */
220 	if (channel->ul_pipe.old_tail != channel->ul_pipe.old_head) {
221 		ipc_imem->app_notify_ul_pend = 1;
222 
223 		/* Suspend the user app and wait a certain time for processing
224 		 * UL Data.
225 		 */
226 		status = wait_for_completion_interruptible_timeout
227 			 (&ipc_imem->ul_pend_sem,
228 			  msecs_to_jiffies(IPC_PEND_DATA_TIMEOUT));
229 		if (status == 0) {
230 			dev_dbg(ipc_imem->dev,
231 				"Pend data Timeout UL-Pipe:%d Head:%d Tail:%d",
232 				channel->ul_pipe.pipe_nr,
233 				channel->ul_pipe.old_head,
234 				channel->ul_pipe.old_tail);
235 		}
236 
237 		ipc_imem->app_notify_ul_pend = 0;
238 	}
239 
240 	/* If there are any pending TDs then wait for Timeout/Completion before
241 	 * closing pipe.
242 	 */
243 	ipc_protocol_get_head_tail_index(ipc_imem->ipc_protocol,
244 					 &channel->dl_pipe, NULL, &tail);
245 
246 	if (tail != channel->dl_pipe.old_tail) {
247 		ipc_imem->app_notify_dl_pend = 1;
248 
249 		/* Suspend the user app and wait a certain time for processing
250 		 * DL Data.
251 		 */
252 		status = wait_for_completion_interruptible_timeout
253 			 (&ipc_imem->dl_pend_sem,
254 			  msecs_to_jiffies(IPC_PEND_DATA_TIMEOUT));
255 		if (status == 0) {
256 			dev_dbg(ipc_imem->dev,
257 				"Pend data Timeout DL-Pipe:%d Head:%d Tail:%d",
258 				channel->dl_pipe.pipe_nr,
259 				channel->dl_pipe.old_head,
260 				channel->dl_pipe.old_tail);
261 		}
262 
263 		ipc_imem->app_notify_dl_pend = 0;
264 	}
265 
266 	/* Due to wait for completion in messages, there is a small window
267 	 * between closing the pipe and updating the channel is closed. In this
268 	 * small window there could be HP update from Host Driver. Hence update
269 	 * the channel state as CLOSING to aviod unnecessary interrupt
270 	 * towards CP.
271 	 */
272 	channel->state = IMEM_CHANNEL_CLOSING;
273 
274 	ipc_imem_pipe_close(ipc_imem, &channel->ul_pipe);
275 	ipc_imem_pipe_close(ipc_imem, &channel->dl_pipe);
276 
277 	ipc_imem_channel_free(channel);
278 }
279 
280 /* Open a PORT link to CP and return the channel */
281 struct ipc_mem_channel *ipc_imem_sys_port_open(struct iosm_imem *ipc_imem,
282 					       int chl_id, int hp_id)
283 {
284 	struct ipc_mem_channel *channel;
285 	int ch_id;
286 
287 	/* The PORT interface is only supported in the runtime phase. */
288 	if (ipc_imem_phase_update(ipc_imem) != IPC_P_RUN) {
289 		dev_err(ipc_imem->dev, "PORT open refused, phase %s",
290 			ipc_imem_phase_get_string(ipc_imem->phase));
291 		return NULL;
292 	}
293 
294 	ch_id = ipc_imem_channel_alloc(ipc_imem, chl_id, IPC_CTYPE_CTRL);
295 
296 	if (ch_id < 0) {
297 		dev_err(ipc_imem->dev, "reservation of an PORT chnl id failed");
298 		return NULL;
299 	}
300 
301 	channel = ipc_imem_channel_open(ipc_imem, ch_id, hp_id);
302 
303 	if (!channel) {
304 		dev_err(ipc_imem->dev, "PORT channel id open failed");
305 		return NULL;
306 	}
307 
308 	return channel;
309 }
310 
311 /* transfer skb to modem */
312 int ipc_imem_sys_cdev_write(struct iosm_cdev *ipc_cdev, struct sk_buff *skb)
313 {
314 	struct ipc_mem_channel *channel = ipc_cdev->channel;
315 	struct iosm_imem *ipc_imem = ipc_cdev->ipc_imem;
316 	int ret = -EIO;
317 
318 	if (!ipc_imem_is_channel_active(ipc_imem, channel) ||
319 	    ipc_imem->phase == IPC_P_OFF_REQ)
320 		goto out;
321 
322 	ret = ipc_imem_map_skb_to_dma(ipc_imem, skb);
323 
324 	if (ret)
325 		goto out;
326 
327 	/* Add skb to the uplink skbuf accumulator. */
328 	skb_queue_tail(&channel->ul_list, skb);
329 
330 	ret = ipc_imem_call_cdev_write(ipc_imem);
331 
332 	if (ret) {
333 		skb_dequeue_tail(&channel->ul_list);
334 		dev_err(ipc_cdev->dev, "channel id[%d] write failed\n",
335 			ipc_cdev->channel->channel_id);
336 	}
337 out:
338 	return ret;
339 }
340 
341 /* Open a SIO link to CP and return the channel instance */
342 struct ipc_mem_channel *ipc_imem_sys_devlink_open(struct iosm_imem *ipc_imem)
343 {
344 	struct ipc_mem_channel *channel;
345 	enum ipc_phase phase;
346 	int channel_id;
347 
348 	phase = ipc_imem_phase_update(ipc_imem);
349 	switch (phase) {
350 	case IPC_P_OFF:
351 	case IPC_P_ROM:
352 		/* Get a channel id as flash id and reserve it. */
353 		channel_id = ipc_imem_channel_alloc(ipc_imem,
354 						    IPC_MEM_CTRL_CHL_ID_7,
355 						    IPC_CTYPE_CTRL);
356 
357 		if (channel_id < 0) {
358 			dev_err(ipc_imem->dev,
359 				"reservation of a flash channel id failed");
360 			goto error;
361 		}
362 
363 		ipc_imem->ipc_devlink->devlink_sio.channel_id = channel_id;
364 		channel = &ipc_imem->channels[channel_id];
365 
366 		/* Enqueue chip info data to be read */
367 		if (ipc_imem_devlink_trigger_chip_info(ipc_imem)) {
368 			dev_err(ipc_imem->dev, "Enqueue of chip info failed");
369 			channel->state = IMEM_CHANNEL_FREE;
370 			goto error;
371 		}
372 
373 		return channel;
374 
375 	case IPC_P_PSI:
376 	case IPC_P_EBL:
377 		ipc_imem->cp_version = ipc_mmio_get_cp_version(ipc_imem->mmio);
378 		if (ipc_imem->cp_version == -1) {
379 			dev_err(ipc_imem->dev, "invalid CP version");
380 			goto error;
381 		}
382 
383 		channel_id = ipc_imem->ipc_devlink->devlink_sio.channel_id;
384 		return ipc_imem_channel_open(ipc_imem, channel_id,
385 					     IPC_HP_CDEV_OPEN);
386 
387 	default:
388 		/* CP is in the wrong state (e.g. CRASH or CD_READY) */
389 		dev_err(ipc_imem->dev, "SIO open refused, phase %d", phase);
390 	}
391 error:
392 	return NULL;
393 }
394 
395 /* Release a SIO channel link to CP. */
396 void ipc_imem_sys_devlink_close(struct iosm_devlink *ipc_devlink)
397 {
398 	struct iosm_imem *ipc_imem = ipc_devlink->pcie->imem;
399 	int boot_check_timeout = BOOT_CHECK_DEFAULT_TIMEOUT;
400 	enum ipc_mem_exec_stage exec_stage;
401 	struct ipc_mem_channel *channel;
402 	int status = 0;
403 	u32 tail = 0;
404 
405 	channel = ipc_imem->ipc_devlink->devlink_sio.channel;
406 	/* Increase the total wait time to boot_check_timeout */
407 	do {
408 		exec_stage = ipc_mmio_get_exec_stage(ipc_imem->mmio);
409 		if (exec_stage == IPC_MEM_EXEC_STAGE_RUN ||
410 		    exec_stage == IPC_MEM_EXEC_STAGE_PSI)
411 			break;
412 		msleep(20);
413 		boot_check_timeout -= 20;
414 	} while (boot_check_timeout > 0);
415 
416 	/* If there are any pending TDs then wait for Timeout/Completion before
417 	 * closing pipe.
418 	 */
419 	if (channel->ul_pipe.old_tail != channel->ul_pipe.old_head) {
420 		status = wait_for_completion_interruptible_timeout
421 			(&ipc_imem->ul_pend_sem,
422 			 msecs_to_jiffies(IPC_PEND_DATA_TIMEOUT));
423 		if (status == 0) {
424 			dev_dbg(ipc_imem->dev,
425 				"Data Timeout on UL-Pipe:%d Head:%d Tail:%d",
426 				channel->ul_pipe.pipe_nr,
427 				channel->ul_pipe.old_head,
428 				channel->ul_pipe.old_tail);
429 		}
430 	}
431 
432 	ipc_protocol_get_head_tail_index(ipc_imem->ipc_protocol,
433 					 &channel->dl_pipe, NULL, &tail);
434 
435 	if (tail != channel->dl_pipe.old_tail) {
436 		status = wait_for_completion_interruptible_timeout
437 			(&ipc_imem->dl_pend_sem,
438 			 msecs_to_jiffies(IPC_PEND_DATA_TIMEOUT));
439 		if (status == 0) {
440 			dev_dbg(ipc_imem->dev,
441 				"Data Timeout on DL-Pipe:%d Head:%d Tail:%d",
442 				channel->dl_pipe.pipe_nr,
443 				channel->dl_pipe.old_head,
444 				channel->dl_pipe.old_tail);
445 		}
446 	}
447 
448 	/* Due to wait for completion in messages, there is a small window
449 	 * between closing the pipe and updating the channel is closed. In this
450 	 * small window there could be HP update from Host Driver. Hence update
451 	 * the channel state as CLOSING to aviod unnecessary interrupt
452 	 * towards CP.
453 	 */
454 	channel->state = IMEM_CHANNEL_CLOSING;
455 	/* Release the pipe resources */
456 	ipc_imem_pipe_cleanup(ipc_imem, &channel->ul_pipe);
457 	ipc_imem_pipe_cleanup(ipc_imem, &channel->dl_pipe);
458 	ipc_imem->nr_of_channels--;
459 }
460 
461 void ipc_imem_sys_devlink_notify_rx(struct iosm_devlink *ipc_devlink,
462 				    struct sk_buff *skb)
463 {
464 	skb_queue_tail(&ipc_devlink->devlink_sio.rx_list, skb);
465 	complete(&ipc_devlink->devlink_sio.read_sem);
466 }
467 
468 /* PSI transfer */
469 static int ipc_imem_sys_psi_transfer(struct iosm_imem *ipc_imem,
470 				     struct ipc_mem_channel *channel,
471 				     unsigned char *buf, int count)
472 {
473 	int psi_start_timeout = PSI_START_DEFAULT_TIMEOUT;
474 	enum ipc_mem_exec_stage exec_stage;
475 
476 	dma_addr_t mapping = 0;
477 	int ret;
478 
479 	ret = ipc_pcie_addr_map(ipc_imem->pcie, buf, count, &mapping,
480 				DMA_TO_DEVICE);
481 	if (ret)
482 		goto pcie_addr_map_fail;
483 
484 	/* Save the PSI information for the CP ROM driver on the doorbell
485 	 * scratchpad.
486 	 */
487 	ipc_mmio_set_psi_addr_and_size(ipc_imem->mmio, mapping, count);
488 	ipc_doorbell_fire(ipc_imem->pcie, 0, IPC_MEM_EXEC_STAGE_BOOT);
489 
490 	ret = wait_for_completion_interruptible_timeout
491 		(&channel->ul_sem,
492 		 msecs_to_jiffies(IPC_PSI_TRANSFER_TIMEOUT));
493 
494 	if (ret <= 0) {
495 		dev_err(ipc_imem->dev, "Failed PSI transfer to CP, Error-%d",
496 			ret);
497 		goto psi_transfer_fail;
498 	}
499 	/* If the PSI download fails, return the CP boot ROM exit code */
500 	if (ipc_imem->rom_exit_code != IMEM_ROM_EXIT_OPEN_EXT &&
501 	    ipc_imem->rom_exit_code != IMEM_ROM_EXIT_CERT_EXT) {
502 		ret = (-1) * ((int)ipc_imem->rom_exit_code);
503 		goto psi_transfer_fail;
504 	}
505 
506 	dev_dbg(ipc_imem->dev, "PSI image successfully downloaded");
507 
508 	/* Wait psi_start_timeout milliseconds until the CP PSI image is
509 	 * running and updates the execution_stage field with
510 	 * IPC_MEM_EXEC_STAGE_PSI. Verify the execution stage.
511 	 */
512 	do {
513 		exec_stage = ipc_mmio_get_exec_stage(ipc_imem->mmio);
514 
515 		if (exec_stage == IPC_MEM_EXEC_STAGE_PSI)
516 			break;
517 
518 		msleep(20);
519 		psi_start_timeout -= 20;
520 	} while (psi_start_timeout > 0);
521 
522 	if (exec_stage != IPC_MEM_EXEC_STAGE_PSI)
523 		goto psi_transfer_fail; /* Unknown status of CP PSI process. */
524 
525 	ipc_imem->phase = IPC_P_PSI;
526 
527 	/* Enter the PSI phase. */
528 	dev_dbg(ipc_imem->dev, "execution_stage[%X] eq. PSI", exec_stage);
529 
530 	/* Request the RUNNING state from CP and wait until it was reached
531 	 * or timeout.
532 	 */
533 	ipc_imem_ipc_init_check(ipc_imem);
534 
535 	ret = wait_for_completion_interruptible_timeout
536 		(&channel->ul_sem, msecs_to_jiffies(IPC_PSI_TRANSFER_TIMEOUT));
537 	if (ret <= 0) {
538 		dev_err(ipc_imem->dev,
539 			"Failed PSI RUNNING state on CP, Error-%d", ret);
540 		goto psi_transfer_fail;
541 	}
542 
543 	if (ipc_mmio_get_ipc_state(ipc_imem->mmio) !=
544 			IPC_MEM_DEVICE_IPC_RUNNING) {
545 		dev_err(ipc_imem->dev,
546 			"ch[%d] %s: unexpected CP IPC state %d, not RUNNING",
547 			channel->channel_id,
548 			ipc_imem_phase_get_string(ipc_imem->phase),
549 			ipc_mmio_get_ipc_state(ipc_imem->mmio));
550 
551 		goto psi_transfer_fail;
552 	}
553 
554 	/* Create the flash channel for the transfer of the images. */
555 	if (!ipc_imem_sys_devlink_open(ipc_imem)) {
556 		dev_err(ipc_imem->dev, "can't open flash_channel");
557 		goto psi_transfer_fail;
558 	}
559 
560 	ret = 0;
561 psi_transfer_fail:
562 	ipc_pcie_addr_unmap(ipc_imem->pcie, count, mapping, DMA_TO_DEVICE);
563 pcie_addr_map_fail:
564 	return ret;
565 }
566 
567 int ipc_imem_sys_devlink_write(struct iosm_devlink *ipc_devlink,
568 			       unsigned char *buf, int count)
569 {
570 	struct iosm_imem *ipc_imem = ipc_devlink->pcie->imem;
571 	struct ipc_mem_channel *channel;
572 	struct sk_buff *skb;
573 	dma_addr_t mapping;
574 	int ret;
575 
576 	channel = ipc_imem->ipc_devlink->devlink_sio.channel;
577 
578 	/* In the ROM phase the PSI image is passed to CP about a specific
579 	 *  shared memory area and doorbell scratchpad directly.
580 	 */
581 	if (ipc_imem->phase == IPC_P_ROM) {
582 		ret = ipc_imem_sys_psi_transfer(ipc_imem, channel, buf, count);
583 		/* If the PSI transfer fails then send crash
584 		 * Signature.
585 		 */
586 		if (ret > 0)
587 			ipc_imem_msg_send_feature_set(ipc_imem,
588 						      IPC_MEM_INBAND_CRASH_SIG,
589 						      false);
590 		goto out;
591 	}
592 
593 	/* Allocate skb memory for the uplink buffer. */
594 	skb = ipc_pcie_alloc_skb(ipc_devlink->pcie, count, GFP_KERNEL, &mapping,
595 				 DMA_TO_DEVICE, 0);
596 	if (!skb) {
597 		ret = -ENOMEM;
598 		goto out;
599 	}
600 
601 	skb_put_data(skb, buf, count);
602 
603 	IPC_CB(skb)->op_type = UL_USR_OP_BLOCKED;
604 
605 	/* Add skb to the uplink skbuf accumulator. */
606 	skb_queue_tail(&channel->ul_list, skb);
607 
608 	/* Inform the IPC tasklet to pass uplink IP packets to CP. */
609 	if (!ipc_imem_call_cdev_write(ipc_imem)) {
610 		ret = wait_for_completion_interruptible(&channel->ul_sem);
611 
612 		if (ret < 0) {
613 			dev_err(ipc_imem->dev,
614 				"ch[%d] no CP confirmation, status = %d",
615 				channel->channel_id, ret);
616 			ipc_pcie_kfree_skb(ipc_devlink->pcie, skb);
617 			goto out;
618 		}
619 	}
620 	ret = 0;
621 out:
622 	return ret;
623 }
624 
625 int ipc_imem_sys_devlink_read(struct iosm_devlink *devlink, u8 *data,
626 			      u32 bytes_to_read, u32 *bytes_read)
627 {
628 	struct sk_buff *skb = NULL;
629 	int rc = 0;
630 
631 	/* check skb is available in rx_list or wait for skb */
632 	devlink->devlink_sio.devlink_read_pend = 1;
633 	while (!skb && !(skb = skb_dequeue(&devlink->devlink_sio.rx_list))) {
634 		if (!wait_for_completion_interruptible_timeout
635 				(&devlink->devlink_sio.read_sem,
636 				 msecs_to_jiffies(IPC_READ_TIMEOUT))) {
637 			dev_err(devlink->dev, "Read timedout");
638 			rc =  -ETIMEDOUT;
639 			goto devlink_read_fail;
640 		}
641 	}
642 	devlink->devlink_sio.devlink_read_pend = 0;
643 	if (bytes_to_read < skb->len) {
644 		dev_err(devlink->dev, "Invalid size,expected len %d", skb->len);
645 		rc = -EINVAL;
646 		goto devlink_read_fail;
647 	}
648 	*bytes_read = skb->len;
649 	memcpy(data, skb->data, skb->len);
650 
651 devlink_read_fail:
652 	dev_kfree_skb(skb);
653 	return rc;
654 }
655