1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * aspeed-vhub -- Driver for Aspeed SoC "vHub" USB gadget
4  *
5  * epn.c - Generic endpoints management
6  *
7  * Copyright 2017 IBM Corporation
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License as published by
11  * the Free Software Foundation; either version 2 of the License, or
12  * (at your option) any later version.
13  */
14 
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/platform_device.h>
18 #include <linux/delay.h>
19 #include <linux/ioport.h>
20 #include <linux/slab.h>
21 #include <linux/errno.h>
22 #include <linux/list.h>
23 #include <linux/interrupt.h>
24 #include <linux/proc_fs.h>
25 #include <linux/prefetch.h>
26 #include <linux/clk.h>
27 #include <linux/usb/gadget.h>
28 #include <linux/of.h>
29 #include <linux/of_gpio.h>
30 #include <linux/regmap.h>
31 #include <linux/dma-mapping.h>
32 
33 #include "vhub.h"
34 
35 #define EXTRA_CHECKS
36 
37 #ifdef EXTRA_CHECKS
38 #define CHECK(ep, expr, fmt...)					\
39 	do {							\
40 		if (!(expr)) EPDBG(ep, "CHECK:" fmt);		\
41 	} while(0)
42 #else
43 #define CHECK(ep, expr, fmt...)	do { } while(0)
44 #endif
45 
46 static void ast_vhub_epn_kick(struct ast_vhub_ep *ep, struct ast_vhub_req *req)
47 {
48 	unsigned int act = req->req.actual;
49 	unsigned int len = req->req.length;
50 	unsigned int chunk;
51 
52 	/* There should be no DMA ongoing */
53 	WARN_ON(req->active);
54 
55 	/* Calculate next chunk size */
56 	chunk = len - act;
57 	if (chunk > ep->ep.maxpacket)
58 		chunk = ep->ep.maxpacket;
59 	else if ((chunk < ep->ep.maxpacket) || !req->req.zero)
60 		req->last_desc = 1;
61 
62 	EPVDBG(ep, "kick req %p act=%d/%d chunk=%d last=%d\n",
63 	       req, act, len, chunk, req->last_desc);
64 
65 	/* If DMA unavailable, using staging EP buffer */
66 	if (!req->req.dma) {
67 
68 		/* For IN transfers, copy data over first */
69 		if (ep->epn.is_in) {
70 			memcpy(ep->buf, req->req.buf + act, chunk);
71 			vhub_dma_workaround(ep->buf);
72 		}
73 		writel(ep->buf_dma, ep->epn.regs + AST_VHUB_EP_DESC_BASE);
74 	} else {
75 		if (ep->epn.is_in)
76 			vhub_dma_workaround(req->req.buf);
77 		writel(req->req.dma + act, ep->epn.regs + AST_VHUB_EP_DESC_BASE);
78 	}
79 
80 	/* Start DMA */
81 	req->active = true;
82 	writel(VHUB_EP_DMA_SET_TX_SIZE(chunk),
83 	       ep->epn.regs + AST_VHUB_EP_DESC_STATUS);
84 	writel(VHUB_EP_DMA_SET_TX_SIZE(chunk) | VHUB_EP_DMA_SINGLE_KICK,
85 	       ep->epn.regs + AST_VHUB_EP_DESC_STATUS);
86 }
87 
88 static void ast_vhub_epn_handle_ack(struct ast_vhub_ep *ep)
89 {
90 	struct ast_vhub_req *req;
91 	unsigned int len;
92 	u32 stat;
93 
94 	/* Read EP status */
95 	stat = readl(ep->epn.regs + AST_VHUB_EP_DESC_STATUS);
96 
97 	/* Grab current request if any */
98 	req = list_first_entry_or_null(&ep->queue, struct ast_vhub_req, queue);
99 
100 	EPVDBG(ep, "ACK status=%08x is_in=%d, req=%p (active=%d)\n",
101 	       stat, ep->epn.is_in, req, req ? req->active : 0);
102 
103 	/* In absence of a request, bail out, must have been dequeued */
104 	if (!req)
105 		return;
106 
107 	/*
108 	 * Request not active, move on to processing queue, active request
109 	 * was probably dequeued
110 	 */
111 	if (!req->active)
112 		goto next_chunk;
113 
114 	/* Check if HW has moved on */
115 	if (VHUB_EP_DMA_RPTR(stat) != 0) {
116 		EPDBG(ep, "DMA read pointer not 0 !\n");
117 		return;
118 	}
119 
120 	/* No current DMA ongoing */
121 	req->active = false;
122 
123 	/* Grab length out of HW */
124 	len = VHUB_EP_DMA_TX_SIZE(stat);
125 
126 	/* If not using DMA, copy data out if needed */
127 	if (!req->req.dma && !ep->epn.is_in && len)
128 		memcpy(req->req.buf + req->req.actual, ep->buf, len);
129 
130 	/* Adjust size */
131 	req->req.actual += len;
132 
133 	/* Check for short packet */
134 	if (len < ep->ep.maxpacket)
135 		req->last_desc = 1;
136 
137 	/* That's it ? complete the request and pick a new one */
138 	if (req->last_desc >= 0) {
139 		ast_vhub_done(ep, req, 0);
140 		req = list_first_entry_or_null(&ep->queue, struct ast_vhub_req,
141 					       queue);
142 
143 		/*
144 		 * Due to lock dropping inside "done" the next request could
145 		 * already be active, so check for that and bail if needed.
146 		 */
147 		if (!req || req->active)
148 			return;
149 	}
150 
151  next_chunk:
152 	ast_vhub_epn_kick(ep, req);
153 }
154 
155 static inline unsigned int ast_vhub_count_free_descs(struct ast_vhub_ep *ep)
156 {
157 	/*
158 	 * d_next == d_last means descriptor list empty to HW,
159 	 * thus we can only have AST_VHUB_DESCS_COUNT-1 descriptors
160 	 * in the list
161 	 */
162 	return (ep->epn.d_last + AST_VHUB_DESCS_COUNT - ep->epn.d_next - 1) &
163 		(AST_VHUB_DESCS_COUNT - 1);
164 }
165 
166 static void ast_vhub_epn_kick_desc(struct ast_vhub_ep *ep,
167 				   struct ast_vhub_req *req)
168 {
169 	struct ast_vhub_desc *desc = NULL;
170 	unsigned int act = req->act_count;
171 	unsigned int len = req->req.length;
172 	unsigned int chunk;
173 
174 	/* Mark request active if not already */
175 	req->active = true;
176 
177 	/* If the request was already completely written, do nothing */
178 	if (req->last_desc >= 0)
179 		return;
180 
181 	EPVDBG(ep, "kick act=%d/%d chunk_max=%d free_descs=%d\n",
182 	       act, len, ep->epn.chunk_max, ast_vhub_count_free_descs(ep));
183 
184 	/* While we can create descriptors */
185 	while (ast_vhub_count_free_descs(ep) && req->last_desc < 0) {
186 		unsigned int d_num;
187 
188 		/* Grab next free descriptor */
189 		d_num = ep->epn.d_next;
190 		desc = &ep->epn.descs[d_num];
191 		ep->epn.d_next = (d_num + 1) & (AST_VHUB_DESCS_COUNT - 1);
192 
193 		/* Calculate next chunk size */
194 		chunk = len - act;
195 		if (chunk <= ep->epn.chunk_max) {
196 			/*
197 			 * Is this the last packet ? Because of having up to 8
198 			 * packets in a descriptor we can't just compare "chunk"
199 			 * with ep.maxpacket. We have to see if it's a multiple
200 			 * of it to know if we have to send a zero packet.
201 			 * Sadly that involves a modulo which is a bit expensive
202 			 * but probably still better than not doing it.
203 			 */
204 			if (!chunk || !req->req.zero || (chunk % ep->ep.maxpacket) != 0)
205 				req->last_desc = d_num;
206 		} else {
207 			chunk = ep->epn.chunk_max;
208 		}
209 
210 		EPVDBG(ep, " chunk: act=%d/%d chunk=%d last=%d desc=%d free=%d\n",
211 		       act, len, chunk, req->last_desc, d_num,
212 		       ast_vhub_count_free_descs(ep));
213 
214 		/* Populate descriptor */
215 		desc->w0 = cpu_to_le32(req->req.dma + act);
216 
217 		/* Interrupt if end of request or no more descriptors */
218 
219 		/*
220 		 * TODO: Be smarter about it, if we don't have enough
221 		 * descriptors request an interrupt before queue empty
222 		 * or so in order to be able to populate more before
223 		 * the HW runs out. This isn't a problem at the moment
224 		 * as we use 256 descriptors and only put at most one
225 		 * request in the ring.
226 		 */
227 		desc->w1 = cpu_to_le32(VHUB_DSC1_IN_SET_LEN(chunk));
228 		if (req->last_desc >= 0 || !ast_vhub_count_free_descs(ep))
229 			desc->w1 |= cpu_to_le32(VHUB_DSC1_IN_INTERRUPT);
230 
231 		/* Account packet */
232 		req->act_count = act = act + chunk;
233 	}
234 
235 	if (likely(desc))
236 		vhub_dma_workaround(desc);
237 
238 	/* Tell HW about new descriptors */
239 	writel(VHUB_EP_DMA_SET_CPU_WPTR(ep->epn.d_next),
240 	       ep->epn.regs + AST_VHUB_EP_DESC_STATUS);
241 
242 	EPVDBG(ep, "HW kicked, d_next=%d dstat=%08x\n",
243 	       ep->epn.d_next, readl(ep->epn.regs + AST_VHUB_EP_DESC_STATUS));
244 }
245 
246 static void ast_vhub_epn_handle_ack_desc(struct ast_vhub_ep *ep)
247 {
248 	struct ast_vhub_req *req;
249 	unsigned int len, d_last;
250 	u32 stat, stat1;
251 
252 	/* Read EP status, workaround HW race */
253 	do {
254 		stat = readl(ep->epn.regs + AST_VHUB_EP_DESC_STATUS);
255 		stat1 = readl(ep->epn.regs + AST_VHUB_EP_DESC_STATUS);
256 	} while(stat != stat1);
257 
258 	/* Extract RPTR */
259 	d_last = VHUB_EP_DMA_RPTR(stat);
260 
261 	/* Grab current request if any */
262 	req = list_first_entry_or_null(&ep->queue, struct ast_vhub_req, queue);
263 
264 	EPVDBG(ep, "ACK status=%08x is_in=%d ep->d_last=%d..%d\n",
265 	       stat, ep->epn.is_in, ep->epn.d_last, d_last);
266 
267 	/* Check all completed descriptors */
268 	while (ep->epn.d_last != d_last) {
269 		struct ast_vhub_desc *desc;
270 		unsigned int d_num;
271 		bool is_last_desc;
272 
273 		/* Grab next completed descriptor */
274 		d_num = ep->epn.d_last;
275 		desc = &ep->epn.descs[d_num];
276 		ep->epn.d_last = (d_num + 1) & (AST_VHUB_DESCS_COUNT - 1);
277 
278 		/* Grab len out of descriptor */
279 		len = VHUB_DSC1_IN_LEN(le32_to_cpu(desc->w1));
280 
281 		EPVDBG(ep, " desc %d len=%d req=%p (act=%d)\n",
282 		       d_num, len, req, req ? req->active : 0);
283 
284 		/* If no active request pending, move on */
285 		if (!req || !req->active)
286 			continue;
287 
288 		/* Adjust size */
289 		req->req.actual += len;
290 
291 		/* Is that the last chunk ? */
292 		is_last_desc = req->last_desc == d_num;
293 		CHECK(ep, is_last_desc == (len < ep->ep.maxpacket ||
294 					   (req->req.actual >= req->req.length &&
295 					    !req->req.zero)),
296 		      "Last packet discrepancy: last_desc=%d len=%d r.act=%d "
297 		      "r.len=%d r.zero=%d mp=%d\n",
298 		      is_last_desc, len, req->req.actual, req->req.length,
299 		      req->req.zero, ep->ep.maxpacket);
300 
301 		if (is_last_desc) {
302 			/*
303 			 * Because we can only have one request at a time
304 			 * in our descriptor list in this implementation,
305 			 * d_last and ep->d_last should now be equal
306 			 */
307 			CHECK(ep, d_last == ep->epn.d_last,
308 			      "DMA read ptr mismatch %d vs %d\n",
309 			      d_last, ep->epn.d_last);
310 
311 			/* Note: done will drop and re-acquire the lock */
312 			ast_vhub_done(ep, req, 0);
313 			req = list_first_entry_or_null(&ep->queue,
314 						       struct ast_vhub_req,
315 						       queue);
316 			break;
317 		}
318 	}
319 
320 	/* More work ? */
321 	if (req)
322 		ast_vhub_epn_kick_desc(ep, req);
323 }
324 
325 void ast_vhub_epn_ack_irq(struct ast_vhub_ep *ep)
326 {
327 	if (ep->epn.desc_mode)
328 		ast_vhub_epn_handle_ack_desc(ep);
329 	else
330 		ast_vhub_epn_handle_ack(ep);
331 }
332 
333 static int ast_vhub_epn_queue(struct usb_ep* u_ep, struct usb_request *u_req,
334 			      gfp_t gfp_flags)
335 {
336 	struct ast_vhub_req *req = to_ast_req(u_req);
337 	struct ast_vhub_ep *ep = to_ast_ep(u_ep);
338 	struct ast_vhub *vhub = ep->vhub;
339 	unsigned long flags;
340 	bool empty;
341 	int rc;
342 
343 	/* Paranoid checks */
344 	if (!u_req || !u_req->complete || !u_req->buf) {
345 		dev_warn(&vhub->pdev->dev, "Bogus EPn request ! u_req=%p\n", u_req);
346 		if (u_req) {
347 			dev_warn(&vhub->pdev->dev, "complete=%p internal=%d\n",
348 				 u_req->complete, req->internal);
349 		}
350 		return -EINVAL;
351 	}
352 
353 	/* Endpoint enabled ? */
354 	if (!ep->epn.enabled || !u_ep->desc || !ep->dev || !ep->d_idx ||
355 	    !ep->dev->enabled || ep->dev->suspended) {
356 		EPDBG(ep, "Enqueuing request on wrong or disabled EP\n");
357 		return -ESHUTDOWN;
358 	}
359 
360 	/* Map request for DMA if possible. For now, the rule for DMA is
361 	 * that:
362 	 *
363 	 *  * For single stage mode (no descriptors):
364 	 *
365 	 *   - The buffer is aligned to a 8 bytes boundary (HW requirement)
366 	 *   - For a OUT endpoint, the request size is a multiple of the EP
367 	 *     packet size (otherwise the controller will DMA past the end
368 	 *     of the buffer if the host is sending a too long packet).
369 	 *
370 	 *  * For descriptor mode (tx only for now), always.
371 	 *
372 	 * We could relax the latter by making the decision to use the bounce
373 	 * buffer based on the size of a given *segment* of the request rather
374 	 * than the whole request.
375 	 */
376 	if (ep->epn.desc_mode ||
377 	    ((((unsigned long)u_req->buf & 7) == 0) &&
378 	     (ep->epn.is_in || !(u_req->length & (u_ep->maxpacket - 1))))) {
379 		rc = usb_gadget_map_request(&ep->dev->gadget, u_req,
380 					    ep->epn.is_in);
381 		if (rc) {
382 			dev_warn(&vhub->pdev->dev,
383 				 "Request mapping failure %d\n", rc);
384 			return rc;
385 		}
386 	} else
387 		u_req->dma = 0;
388 
389 	EPVDBG(ep, "enqueue req @%p\n", req);
390 	EPVDBG(ep, " l=%d dma=0x%x zero=%d noshort=%d noirq=%d is_in=%d\n",
391 	       u_req->length, (u32)u_req->dma, u_req->zero,
392 	       u_req->short_not_ok, u_req->no_interrupt,
393 	       ep->epn.is_in);
394 
395 	/* Initialize request progress fields */
396 	u_req->status = -EINPROGRESS;
397 	u_req->actual = 0;
398 	req->act_count = 0;
399 	req->active = false;
400 	req->last_desc = -1;
401 	spin_lock_irqsave(&vhub->lock, flags);
402 	empty = list_empty(&ep->queue);
403 
404 	/* Add request to list and kick processing if empty */
405 	list_add_tail(&req->queue, &ep->queue);
406 	if (empty) {
407 		if (ep->epn.desc_mode)
408 			ast_vhub_epn_kick_desc(ep, req);
409 		else
410 			ast_vhub_epn_kick(ep, req);
411 	}
412 	spin_unlock_irqrestore(&vhub->lock, flags);
413 
414 	return 0;
415 }
416 
417 static void ast_vhub_stop_active_req(struct ast_vhub_ep *ep,
418 				     bool restart_ep)
419 {
420 	u32 state, reg, loops;
421 
422 	/* Stop DMA activity */
423 	writel(0, ep->epn.regs + AST_VHUB_EP_DMA_CTLSTAT);
424 
425 	/* Wait for it to complete */
426 	for (loops = 0; loops < 1000; loops++) {
427 		state = readl(ep->epn.regs + AST_VHUB_EP_DMA_CTLSTAT);
428 		state = VHUB_EP_DMA_PROC_STATUS(state);
429 		if (state == EP_DMA_PROC_RX_IDLE ||
430 		    state == EP_DMA_PROC_TX_IDLE)
431 			break;
432 		udelay(1);
433 	}
434 	if (loops >= 1000)
435 		dev_warn(&ep->vhub->pdev->dev, "Timeout waiting for DMA\n");
436 
437 	/* If we don't have to restart the endpoint, that's it */
438 	if (!restart_ep)
439 		return;
440 
441 	/* Restart the endpoint */
442 	if (ep->epn.desc_mode) {
443 		/*
444 		 * Take out descriptors by resetting the DMA read
445 		 * pointer to be equal to the CPU write pointer.
446 		 *
447 		 * Note: If we ever support creating descriptors for
448 		 * requests that aren't the head of the queue, we
449 		 * may have to do something more complex here,
450 		 * especially if the request being taken out is
451 		 * not the current head descriptors.
452 		 */
453 		reg = VHUB_EP_DMA_SET_RPTR(ep->epn.d_next) |
454 			VHUB_EP_DMA_SET_CPU_WPTR(ep->epn.d_next);
455 		writel(reg, ep->epn.regs + AST_VHUB_EP_DESC_STATUS);
456 
457 		/* Then turn it back on */
458 		writel(ep->epn.dma_conf,
459 		       ep->epn.regs + AST_VHUB_EP_DMA_CTLSTAT);
460 	} else {
461 		/* Single mode: just turn it back on */
462 		writel(ep->epn.dma_conf,
463 		       ep->epn.regs + AST_VHUB_EP_DMA_CTLSTAT);
464 	}
465 }
466 
467 static int ast_vhub_epn_dequeue(struct usb_ep* u_ep, struct usb_request *u_req)
468 {
469 	struct ast_vhub_ep *ep = to_ast_ep(u_ep);
470 	struct ast_vhub *vhub = ep->vhub;
471 	struct ast_vhub_req *req;
472 	unsigned long flags;
473 	int rc = -EINVAL;
474 
475 	spin_lock_irqsave(&vhub->lock, flags);
476 
477 	/* Make sure it's actually queued on this endpoint */
478 	list_for_each_entry (req, &ep->queue, queue) {
479 		if (&req->req == u_req)
480 			break;
481 	}
482 
483 	if (&req->req == u_req) {
484 		EPVDBG(ep, "dequeue req @%p active=%d\n",
485 		       req, req->active);
486 		if (req->active)
487 			ast_vhub_stop_active_req(ep, true);
488 		ast_vhub_done(ep, req, -ECONNRESET);
489 		rc = 0;
490 	}
491 
492 	spin_unlock_irqrestore(&vhub->lock, flags);
493 	return rc;
494 }
495 
496 void ast_vhub_update_epn_stall(struct ast_vhub_ep *ep)
497 {
498 	u32 reg;
499 
500 	if (WARN_ON(ep->d_idx == 0))
501 		return;
502 	reg = readl(ep->epn.regs + AST_VHUB_EP_CONFIG);
503 	if (ep->epn.stalled || ep->epn.wedged)
504 		reg |= VHUB_EP_CFG_STALL_CTRL;
505 	else
506 		reg &= ~VHUB_EP_CFG_STALL_CTRL;
507 	writel(reg, ep->epn.regs + AST_VHUB_EP_CONFIG);
508 
509 	if (!ep->epn.stalled && !ep->epn.wedged)
510 		writel(VHUB_EP_TOGGLE_SET_EPNUM(ep->epn.g_idx),
511 		       ep->vhub->regs + AST_VHUB_EP_TOGGLE);
512 }
513 
514 static int ast_vhub_set_halt_and_wedge(struct usb_ep* u_ep, bool halt,
515 				      bool wedge)
516 {
517 	struct ast_vhub_ep *ep = to_ast_ep(u_ep);
518 	struct ast_vhub *vhub = ep->vhub;
519 	unsigned long flags;
520 
521 	EPDBG(ep, "Set halt (%d) & wedge (%d)\n", halt, wedge);
522 
523 	if (!u_ep || !u_ep->desc)
524 		return -EINVAL;
525 	if (ep->d_idx == 0)
526 		return 0;
527 	if (ep->epn.is_iso)
528 		return -EOPNOTSUPP;
529 
530 	spin_lock_irqsave(&vhub->lock, flags);
531 
532 	/* Fail with still-busy IN endpoints */
533 	if (halt && ep->epn.is_in && !list_empty(&ep->queue)) {
534 		spin_unlock_irqrestore(&vhub->lock, flags);
535 		return -EAGAIN;
536 	}
537 	ep->epn.stalled = halt;
538 	ep->epn.wedged = wedge;
539 	ast_vhub_update_epn_stall(ep);
540 
541 	spin_unlock_irqrestore(&vhub->lock, flags);
542 
543 	return 0;
544 }
545 
546 static int ast_vhub_epn_set_halt(struct usb_ep *u_ep, int value)
547 {
548 	return ast_vhub_set_halt_and_wedge(u_ep, value != 0, false);
549 }
550 
551 static int ast_vhub_epn_set_wedge(struct usb_ep *u_ep)
552 {
553 	return ast_vhub_set_halt_and_wedge(u_ep, true, true);
554 }
555 
556 static int ast_vhub_epn_disable(struct usb_ep* u_ep)
557 {
558 	struct ast_vhub_ep *ep = to_ast_ep(u_ep);
559 	struct ast_vhub *vhub = ep->vhub;
560 	unsigned long flags;
561 	u32 imask, ep_ier;
562 
563 	EPDBG(ep, "Disabling !\n");
564 
565 	spin_lock_irqsave(&vhub->lock, flags);
566 
567 	ep->epn.enabled = false;
568 
569 	/* Stop active DMA if any */
570 	ast_vhub_stop_active_req(ep, false);
571 
572 	/* Disable endpoint */
573 	writel(0, ep->epn.regs + AST_VHUB_EP_CONFIG);
574 
575 	/* Disable ACK interrupt */
576 	imask = VHUB_EP_IRQ(ep->epn.g_idx);
577 	ep_ier = readl(vhub->regs + AST_VHUB_EP_ACK_IER);
578 	ep_ier &= ~imask;
579 	writel(ep_ier, vhub->regs + AST_VHUB_EP_ACK_IER);
580 	writel(imask, vhub->regs + AST_VHUB_EP_ACK_ISR);
581 
582 	/* Nuke all pending requests */
583 	ast_vhub_nuke(ep, -ESHUTDOWN);
584 
585 	/* No more descriptor associated with request */
586 	ep->ep.desc = NULL;
587 
588 	spin_unlock_irqrestore(&vhub->lock, flags);
589 
590 	return 0;
591 }
592 
593 static int ast_vhub_epn_enable(struct usb_ep* u_ep,
594 			       const struct usb_endpoint_descriptor *desc)
595 {
596 	struct ast_vhub_ep *ep = to_ast_ep(u_ep);
597 	struct ast_vhub_dev *dev;
598 	struct ast_vhub *vhub;
599 	u16 maxpacket, type;
600 	unsigned long flags;
601 	u32 ep_conf, ep_ier, imask;
602 
603 	/* Check arguments */
604 	if (!u_ep || !desc)
605 		return -EINVAL;
606 
607 	maxpacket = usb_endpoint_maxp(desc);
608 	if (!ep->d_idx || !ep->dev ||
609 	    desc->bDescriptorType != USB_DT_ENDPOINT ||
610 	    maxpacket == 0 || maxpacket > ep->ep.maxpacket) {
611 		EPDBG(ep, "Invalid EP enable,d_idx=%d,dev=%p,type=%d,mp=%d/%d\n",
612 		      ep->d_idx, ep->dev, desc->bDescriptorType,
613 		      maxpacket, ep->ep.maxpacket);
614 		return -EINVAL;
615 	}
616 	if (ep->d_idx != usb_endpoint_num(desc)) {
617 		EPDBG(ep, "EP number mismatch !\n");
618 		return -EINVAL;
619 	}
620 
621 	if (ep->epn.enabled) {
622 		EPDBG(ep, "Already enabled\n");
623 		return -EBUSY;
624 	}
625 	dev = ep->dev;
626 	vhub = ep->vhub;
627 
628 	/* Check device state */
629 	if (!dev->driver) {
630 		EPDBG(ep, "Bogus device state: driver=%p speed=%d\n",
631 		       dev->driver, dev->gadget.speed);
632 		return -ESHUTDOWN;
633 	}
634 
635 	/* Grab some info from the descriptor */
636 	ep->epn.is_in = usb_endpoint_dir_in(desc);
637 	ep->ep.maxpacket = maxpacket;
638 	type = usb_endpoint_type(desc);
639 	ep->epn.d_next = ep->epn.d_last = 0;
640 	ep->epn.is_iso = false;
641 	ep->epn.stalled = false;
642 	ep->epn.wedged = false;
643 
644 	EPDBG(ep, "Enabling [%s] %s num %d maxpacket=%d\n",
645 	      ep->epn.is_in ? "in" : "out", usb_ep_type_string(type),
646 	      usb_endpoint_num(desc), maxpacket);
647 
648 	/* Can we use DMA descriptor mode ? */
649 	ep->epn.desc_mode = ep->epn.descs && ep->epn.is_in;
650 	if (ep->epn.desc_mode)
651 		memset(ep->epn.descs, 0, 8 * AST_VHUB_DESCS_COUNT);
652 
653 	/*
654 	 * Large send function can send up to 8 packets from
655 	 * one descriptor with a limit of 4095 bytes.
656 	 */
657 	ep->epn.chunk_max = ep->ep.maxpacket;
658 	if (ep->epn.is_in) {
659 		ep->epn.chunk_max <<= 3;
660 		while (ep->epn.chunk_max > 4095)
661 			ep->epn.chunk_max -= ep->ep.maxpacket;
662 	}
663 
664 	switch(type) {
665 	case USB_ENDPOINT_XFER_CONTROL:
666 		EPDBG(ep, "Only one control endpoint\n");
667 		return -EINVAL;
668 	case USB_ENDPOINT_XFER_INT:
669 		ep_conf = VHUB_EP_CFG_SET_TYPE(EP_TYPE_INT);
670 		break;
671 	case USB_ENDPOINT_XFER_BULK:
672 		ep_conf = VHUB_EP_CFG_SET_TYPE(EP_TYPE_BULK);
673 		break;
674 	case USB_ENDPOINT_XFER_ISOC:
675 		ep_conf = VHUB_EP_CFG_SET_TYPE(EP_TYPE_ISO);
676 		ep->epn.is_iso = true;
677 		break;
678 	default:
679 		return -EINVAL;
680 	}
681 
682 	/* Encode the rest of the EP config register */
683 	if (maxpacket < 1024)
684 		ep_conf |= VHUB_EP_CFG_SET_MAX_PKT(maxpacket);
685 	if (!ep->epn.is_in)
686 		ep_conf |= VHUB_EP_CFG_DIR_OUT;
687 	ep_conf |= VHUB_EP_CFG_SET_EP_NUM(usb_endpoint_num(desc));
688 	ep_conf |= VHUB_EP_CFG_ENABLE;
689 	ep_conf |= VHUB_EP_CFG_SET_DEV(dev->index + 1);
690 	EPVDBG(ep, "config=%08x\n", ep_conf);
691 
692 	spin_lock_irqsave(&vhub->lock, flags);
693 
694 	/* Disable HW and reset DMA */
695 	writel(0, ep->epn.regs + AST_VHUB_EP_CONFIG);
696 	writel(VHUB_EP_DMA_CTRL_RESET,
697 	       ep->epn.regs + AST_VHUB_EP_DMA_CTLSTAT);
698 
699 	/* Configure and enable */
700 	writel(ep_conf, ep->epn.regs + AST_VHUB_EP_CONFIG);
701 
702 	if (ep->epn.desc_mode) {
703 		/* Clear DMA status, including the DMA read ptr */
704 		writel(0, ep->epn.regs + AST_VHUB_EP_DESC_STATUS);
705 
706 		/* Set descriptor base */
707 		writel(ep->epn.descs_dma,
708 		       ep->epn.regs + AST_VHUB_EP_DESC_BASE);
709 
710 		/* Set base DMA config value */
711 		ep->epn.dma_conf = VHUB_EP_DMA_DESC_MODE;
712 		if (ep->epn.is_in)
713 			ep->epn.dma_conf |= VHUB_EP_DMA_IN_LONG_MODE;
714 
715 		/* First reset and disable all operations */
716 		writel(ep->epn.dma_conf | VHUB_EP_DMA_CTRL_RESET,
717 		       ep->epn.regs + AST_VHUB_EP_DMA_CTLSTAT);
718 
719 		/* Enable descriptor mode */
720 		writel(ep->epn.dma_conf,
721 		       ep->epn.regs + AST_VHUB_EP_DMA_CTLSTAT);
722 	} else {
723 		/* Set base DMA config value */
724 		ep->epn.dma_conf = VHUB_EP_DMA_SINGLE_STAGE;
725 
726 		/* Reset and switch to single stage mode */
727 		writel(ep->epn.dma_conf | VHUB_EP_DMA_CTRL_RESET,
728 		       ep->epn.regs + AST_VHUB_EP_DMA_CTLSTAT);
729 		writel(ep->epn.dma_conf,
730 		       ep->epn.regs + AST_VHUB_EP_DMA_CTLSTAT);
731 		writel(0, ep->epn.regs + AST_VHUB_EP_DESC_STATUS);
732 	}
733 
734 	/* Cleanup data toggle just in case */
735 	writel(VHUB_EP_TOGGLE_SET_EPNUM(ep->epn.g_idx),
736 	       vhub->regs + AST_VHUB_EP_TOGGLE);
737 
738 	/* Cleanup and enable ACK interrupt */
739 	imask = VHUB_EP_IRQ(ep->epn.g_idx);
740 	writel(imask, vhub->regs + AST_VHUB_EP_ACK_ISR);
741 	ep_ier = readl(vhub->regs + AST_VHUB_EP_ACK_IER);
742 	ep_ier |= imask;
743 	writel(ep_ier, vhub->regs + AST_VHUB_EP_ACK_IER);
744 
745 	/* Woot, we are online ! */
746 	ep->epn.enabled = true;
747 
748 	spin_unlock_irqrestore(&vhub->lock, flags);
749 
750 	return 0;
751 }
752 
753 static void ast_vhub_epn_dispose(struct usb_ep *u_ep)
754 {
755 	struct ast_vhub_ep *ep = to_ast_ep(u_ep);
756 
757 	if (WARN_ON(!ep->dev || !ep->d_idx))
758 		return;
759 
760 	EPDBG(ep, "Releasing endpoint\n");
761 
762 	/* Take it out of the EP list */
763 	list_del_init(&ep->ep.ep_list);
764 
765 	/* Mark the address free in the device */
766 	ep->dev->epns[ep->d_idx - 1] = NULL;
767 
768 	/* Free name & DMA buffers */
769 	kfree(ep->ep.name);
770 	ep->ep.name = NULL;
771 	dma_free_coherent(&ep->vhub->pdev->dev,
772 			  AST_VHUB_EPn_MAX_PACKET +
773 			  8 * AST_VHUB_DESCS_COUNT,
774 			  ep->buf, ep->buf_dma);
775 	ep->buf = NULL;
776 	ep->epn.descs = NULL;
777 
778 	/* Mark free */
779 	ep->dev = NULL;
780 }
781 
782 static const struct usb_ep_ops ast_vhub_epn_ops = {
783 	.enable		= ast_vhub_epn_enable,
784 	.disable	= ast_vhub_epn_disable,
785 	.dispose	= ast_vhub_epn_dispose,
786 	.queue		= ast_vhub_epn_queue,
787 	.dequeue	= ast_vhub_epn_dequeue,
788 	.set_halt	= ast_vhub_epn_set_halt,
789 	.set_wedge	= ast_vhub_epn_set_wedge,
790 	.alloc_request	= ast_vhub_alloc_request,
791 	.free_request	= ast_vhub_free_request,
792 };
793 
794 struct ast_vhub_ep *ast_vhub_alloc_epn(struct ast_vhub_dev *d, u8 addr)
795 {
796 	struct ast_vhub *vhub = d->vhub;
797 	struct ast_vhub_ep *ep;
798 	unsigned long flags;
799 	int i;
800 
801 	/* Find a free one (no device) */
802 	spin_lock_irqsave(&vhub->lock, flags);
803 	for (i = 0; i < AST_VHUB_NUM_GEN_EPs; i++)
804 		if (vhub->epns[i].dev == NULL)
805 			break;
806 	if (i >= AST_VHUB_NUM_GEN_EPs) {
807 		spin_unlock_irqrestore(&vhub->lock, flags);
808 		return NULL;
809 	}
810 
811 	/* Set it up */
812 	ep = &vhub->epns[i];
813 	ep->dev = d;
814 	spin_unlock_irqrestore(&vhub->lock, flags);
815 
816 	DDBG(d, "Allocating gen EP %d for addr %d\n", i, addr);
817 	INIT_LIST_HEAD(&ep->queue);
818 	ep->d_idx = addr;
819 	ep->vhub = vhub;
820 	ep->ep.ops = &ast_vhub_epn_ops;
821 	ep->ep.name = kasprintf(GFP_KERNEL, "ep%d", addr);
822 	d->epns[addr-1] = ep;
823 	ep->epn.g_idx = i;
824 	ep->epn.regs = vhub->regs + 0x200 + (i * 0x10);
825 
826 	ep->buf = dma_alloc_coherent(&vhub->pdev->dev,
827 				     AST_VHUB_EPn_MAX_PACKET +
828 				     8 * AST_VHUB_DESCS_COUNT,
829 				     &ep->buf_dma, GFP_KERNEL);
830 	if (!ep->buf) {
831 		kfree(ep->ep.name);
832 		ep->ep.name = NULL;
833 		return NULL;
834 	}
835 	ep->epn.descs = ep->buf + AST_VHUB_EPn_MAX_PACKET;
836 	ep->epn.descs_dma = ep->buf_dma + AST_VHUB_EPn_MAX_PACKET;
837 
838 	usb_ep_set_maxpacket_limit(&ep->ep, AST_VHUB_EPn_MAX_PACKET);
839 	list_add_tail(&ep->ep.ep_list, &d->gadget.ep_list);
840 	ep->ep.caps.type_iso = true;
841 	ep->ep.caps.type_bulk = true;
842 	ep->ep.caps.type_int = true;
843 	ep->ep.caps.dir_in = true;
844 	ep->ep.caps.dir_out = true;
845 
846 	return ep;
847 }
848