xref: /openbmc/linux/drivers/usb/host/max3421-hcd.c (revision 53a2a90d)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * MAX3421 Host Controller driver for USB.
4  *
5  * Author: David Mosberger-Tang <davidm@egauge.net>
6  *
7  * (C) Copyright 2014 David Mosberger-Tang <davidm@egauge.net>
8  *
9  * MAX3421 is a chip implementing a USB 2.0 Full-/Low-Speed host
10  * controller on a SPI bus.
11  *
12  * Based on:
13  *	o MAX3421E datasheet
14  *		https://datasheets.maximintegrated.com/en/ds/MAX3421E.pdf
15  *	o MAX3421E Programming Guide
16  *		https://www.hdl.co.jp/ftpdata/utl-001/AN3785.pdf
17  *	o gadget/dummy_hcd.c
18  *		For USB HCD implementation.
19  *	o Arduino MAX3421 driver
20  *	     https://github.com/felis/USB_Host_Shield_2.0/blob/master/Usb.cpp
21  *
22  * This file is licenced under the GPL v2.
23  *
24  * Important note on worst-case (full-speed) packet size constraints
25  * (See USB 2.0 Section 5.6.3 and following):
26  *
27  *	- control:	  64 bytes
28  *	- isochronous:	1023 bytes
29  *	- interrupt:	  64 bytes
30  *	- bulk:		  64 bytes
31  *
32  * Since the MAX3421 FIFO size is 64 bytes, we do not have to work about
33  * multi-FIFO writes/reads for a single USB packet *except* for isochronous
34  * transfers.  We don't support isochronous transfers at this time, so we
35  * just assume that a USB packet always fits into a single FIFO buffer.
36  *
37  * NOTE: The June 2006 version of "MAX3421E Programming Guide"
38  * (AN3785) has conflicting info for the RCVDAVIRQ bit:
39  *
40  *	The description of RCVDAVIRQ says "The CPU *must* clear
41  *	this IRQ bit (by writing a 1 to it) before reading the
42  *	RCVFIFO data.
43  *
44  * However, the earlier section on "Programming BULK-IN
45  * Transfers" says * that:
46  *
47  *	After the CPU retrieves the data, it clears the
48  *	RCVDAVIRQ bit.
49  *
50  * The December 2006 version has been corrected and it consistently
51  * states the second behavior is the correct one.
52  *
53  * Synchronous SPI transactions sleep so we can't perform any such
54  * transactions while holding a spin-lock (and/or while interrupts are
55  * masked).  To achieve this, all SPI transactions are issued from a
56  * single thread (max3421_spi_thread).
57  */
58 
59 #include <linux/jiffies.h>
60 #include <linux/module.h>
61 #include <linux/spi/spi.h>
62 #include <linux/usb.h>
63 #include <linux/usb/hcd.h>
64 #include <linux/of.h>
65 
66 #include <linux/platform_data/max3421-hcd.h>
67 
68 #define DRIVER_DESC	"MAX3421 USB Host-Controller Driver"
69 #define DRIVER_VERSION	"1.0"
70 
71 /* 11-bit counter that wraps around (USB 2.0 Section 8.3.3): */
72 #define USB_MAX_FRAME_NUMBER	0x7ff
73 #define USB_MAX_RETRIES		3 /* # of retries before error is reported */
74 
75 /*
76  * Max. # of times we're willing to retransmit a request immediately in
77  * resposne to a NAK.  Afterwards, we fall back on trying once a frame.
78  */
79 #define NAK_MAX_FAST_RETRANSMITS	2
80 
81 #define POWER_BUDGET	500	/* in mA; use 8 for low-power port testing */
82 
83 /* Port-change mask: */
84 #define PORT_C_MASK	((USB_PORT_STAT_C_CONNECTION |	\
85 			  USB_PORT_STAT_C_ENABLE |	\
86 			  USB_PORT_STAT_C_SUSPEND |	\
87 			  USB_PORT_STAT_C_OVERCURRENT | \
88 			  USB_PORT_STAT_C_RESET) << 16)
89 
90 #define MAX3421_GPOUT_COUNT	8
91 
92 enum max3421_rh_state {
93 	MAX3421_RH_RESET,
94 	MAX3421_RH_SUSPENDED,
95 	MAX3421_RH_RUNNING
96 };
97 
98 enum pkt_state {
99 	PKT_STATE_SETUP,	/* waiting to send setup packet to ctrl pipe */
100 	PKT_STATE_TRANSFER,	/* waiting to xfer transfer_buffer */
101 	PKT_STATE_TERMINATE	/* waiting to terminate control transfer */
102 };
103 
104 enum scheduling_pass {
105 	SCHED_PASS_PERIODIC,
106 	SCHED_PASS_NON_PERIODIC,
107 	SCHED_PASS_DONE
108 };
109 
110 /* Bit numbers for max3421_hcd->todo: */
111 enum {
112 	ENABLE_IRQ = 0,
113 	RESET_HCD,
114 	RESET_PORT,
115 	CHECK_UNLINK,
116 	IOPIN_UPDATE
117 };
118 
119 struct max3421_dma_buf {
120 	u8 data[2];
121 };
122 
123 struct max3421_hcd {
124 	spinlock_t lock;
125 
126 	struct task_struct *spi_thread;
127 
128 	enum max3421_rh_state rh_state;
129 	/* lower 16 bits contain port status, upper 16 bits the change mask: */
130 	u32 port_status;
131 
132 	unsigned active:1;
133 
134 	struct list_head ep_list;	/* list of EP's with work */
135 
136 	/*
137 	 * The following are owned by spi_thread (may be accessed by
138 	 * SPI-thread without acquiring the HCD lock:
139 	 */
140 	u8 rev;				/* chip revision */
141 	u16 frame_number;
142 	/*
143 	 * kmalloc'd buffers guaranteed to be in separate (DMA)
144 	 * cache-lines:
145 	 */
146 	struct max3421_dma_buf *tx;
147 	struct max3421_dma_buf *rx;
148 	/*
149 	 * URB we're currently processing.  Must not be reset to NULL
150 	 * unless MAX3421E chip is idle:
151 	 */
152 	struct urb *curr_urb;
153 	enum scheduling_pass sched_pass;
154 	int urb_done;			/* > 0 -> no errors, < 0: errno */
155 	size_t curr_len;
156 	u8 hien;
157 	u8 mode;
158 	u8 iopins[2];
159 	unsigned long todo;
160 #ifdef DEBUG
161 	unsigned long err_stat[16];
162 #endif
163 };
164 
165 struct max3421_ep {
166 	struct usb_host_endpoint *ep;
167 	struct list_head ep_list;
168 	u32 naks;
169 	u16 last_active;		/* frame # this ep was last active */
170 	enum pkt_state pkt_state;
171 	u8 retries;
172 	u8 retransmit;			/* packet needs retransmission */
173 };
174 
175 #define MAX3421_FIFO_SIZE	64
176 
177 #define MAX3421_SPI_DIR_RD	0	/* read register from MAX3421 */
178 #define MAX3421_SPI_DIR_WR	1	/* write register to MAX3421 */
179 
180 /* SPI commands: */
181 #define MAX3421_SPI_DIR_SHIFT	1
182 #define MAX3421_SPI_REG_SHIFT	3
183 
184 #define MAX3421_REG_RCVFIFO	1
185 #define MAX3421_REG_SNDFIFO	2
186 #define MAX3421_REG_SUDFIFO	4
187 #define MAX3421_REG_RCVBC	6
188 #define MAX3421_REG_SNDBC	7
189 #define MAX3421_REG_USBIRQ	13
190 #define MAX3421_REG_USBIEN	14
191 #define MAX3421_REG_USBCTL	15
192 #define MAX3421_REG_CPUCTL	16
193 #define MAX3421_REG_PINCTL	17
194 #define MAX3421_REG_REVISION	18
195 #define MAX3421_REG_IOPINS1	20
196 #define MAX3421_REG_IOPINS2	21
197 #define MAX3421_REG_GPINIRQ	22
198 #define MAX3421_REG_GPINIEN	23
199 #define MAX3421_REG_GPINPOL	24
200 #define MAX3421_REG_HIRQ	25
201 #define MAX3421_REG_HIEN	26
202 #define MAX3421_REG_MODE	27
203 #define MAX3421_REG_PERADDR	28
204 #define MAX3421_REG_HCTL	29
205 #define MAX3421_REG_HXFR	30
206 #define MAX3421_REG_HRSL	31
207 
208 enum {
209 	MAX3421_USBIRQ_OSCOKIRQ_BIT = 0,
210 	MAX3421_USBIRQ_NOVBUSIRQ_BIT = 5,
211 	MAX3421_USBIRQ_VBUSIRQ_BIT
212 };
213 
214 enum {
215 	MAX3421_CPUCTL_IE_BIT = 0,
216 	MAX3421_CPUCTL_PULSEWID0_BIT = 6,
217 	MAX3421_CPUCTL_PULSEWID1_BIT
218 };
219 
220 enum {
221 	MAX3421_USBCTL_PWRDOWN_BIT = 4,
222 	MAX3421_USBCTL_CHIPRES_BIT
223 };
224 
225 enum {
226 	MAX3421_PINCTL_GPXA_BIT	= 0,
227 	MAX3421_PINCTL_GPXB_BIT,
228 	MAX3421_PINCTL_POSINT_BIT,
229 	MAX3421_PINCTL_INTLEVEL_BIT,
230 	MAX3421_PINCTL_FDUPSPI_BIT,
231 	MAX3421_PINCTL_EP0INAK_BIT,
232 	MAX3421_PINCTL_EP2INAK_BIT,
233 	MAX3421_PINCTL_EP3INAK_BIT,
234 };
235 
236 enum {
237 	MAX3421_HI_BUSEVENT_BIT = 0,	/* bus-reset/-resume */
238 	MAX3421_HI_RWU_BIT,		/* remote wakeup */
239 	MAX3421_HI_RCVDAV_BIT,		/* receive FIFO data available */
240 	MAX3421_HI_SNDBAV_BIT,		/* send buffer available */
241 	MAX3421_HI_SUSDN_BIT,		/* suspend operation done */
242 	MAX3421_HI_CONDET_BIT,		/* peripheral connect/disconnect */
243 	MAX3421_HI_FRAME_BIT,		/* frame generator */
244 	MAX3421_HI_HXFRDN_BIT,		/* host transfer done */
245 };
246 
247 enum {
248 	MAX3421_HCTL_BUSRST_BIT = 0,
249 	MAX3421_HCTL_FRMRST_BIT,
250 	MAX3421_HCTL_SAMPLEBUS_BIT,
251 	MAX3421_HCTL_SIGRSM_BIT,
252 	MAX3421_HCTL_RCVTOG0_BIT,
253 	MAX3421_HCTL_RCVTOG1_BIT,
254 	MAX3421_HCTL_SNDTOG0_BIT,
255 	MAX3421_HCTL_SNDTOG1_BIT
256 };
257 
258 enum {
259 	MAX3421_MODE_HOST_BIT = 0,
260 	MAX3421_MODE_LOWSPEED_BIT,
261 	MAX3421_MODE_HUBPRE_BIT,
262 	MAX3421_MODE_SOFKAENAB_BIT,
263 	MAX3421_MODE_SEPIRQ_BIT,
264 	MAX3421_MODE_DELAYISO_BIT,
265 	MAX3421_MODE_DMPULLDN_BIT,
266 	MAX3421_MODE_DPPULLDN_BIT
267 };
268 
269 enum {
270 	MAX3421_HRSL_OK = 0,
271 	MAX3421_HRSL_BUSY,
272 	MAX3421_HRSL_BADREQ,
273 	MAX3421_HRSL_UNDEF,
274 	MAX3421_HRSL_NAK,
275 	MAX3421_HRSL_STALL,
276 	MAX3421_HRSL_TOGERR,
277 	MAX3421_HRSL_WRONGPID,
278 	MAX3421_HRSL_BADBC,
279 	MAX3421_HRSL_PIDERR,
280 	MAX3421_HRSL_PKTERR,
281 	MAX3421_HRSL_CRCERR,
282 	MAX3421_HRSL_KERR,
283 	MAX3421_HRSL_JERR,
284 	MAX3421_HRSL_TIMEOUT,
285 	MAX3421_HRSL_BABBLE,
286 	MAX3421_HRSL_RESULT_MASK = 0xf,
287 	MAX3421_HRSL_RCVTOGRD_BIT = 4,
288 	MAX3421_HRSL_SNDTOGRD_BIT,
289 	MAX3421_HRSL_KSTATUS_BIT,
290 	MAX3421_HRSL_JSTATUS_BIT
291 };
292 
293 /* Return same error-codes as ohci.h:cc_to_error: */
294 static const int hrsl_to_error[] = {
295 	[MAX3421_HRSL_OK] =		0,
296 	[MAX3421_HRSL_BUSY] =		-EINVAL,
297 	[MAX3421_HRSL_BADREQ] =		-EINVAL,
298 	[MAX3421_HRSL_UNDEF] =		-EINVAL,
299 	[MAX3421_HRSL_NAK] =		-EAGAIN,
300 	[MAX3421_HRSL_STALL] =		-EPIPE,
301 	[MAX3421_HRSL_TOGERR] =		-EILSEQ,
302 	[MAX3421_HRSL_WRONGPID] =	-EPROTO,
303 	[MAX3421_HRSL_BADBC] =		-EREMOTEIO,
304 	[MAX3421_HRSL_PIDERR] =		-EPROTO,
305 	[MAX3421_HRSL_PKTERR] =		-EPROTO,
306 	[MAX3421_HRSL_CRCERR] =		-EILSEQ,
307 	[MAX3421_HRSL_KERR] =		-EIO,
308 	[MAX3421_HRSL_JERR] =		-EIO,
309 	[MAX3421_HRSL_TIMEOUT] =	-ETIME,
310 	[MAX3421_HRSL_BABBLE] =		-EOVERFLOW
311 };
312 
313 /*
314  * See https://www.beyondlogic.org/usbnutshell/usb4.shtml#Control for a
315  * reasonable overview of how control transfers use the the IN/OUT
316  * tokens.
317  */
318 #define MAX3421_HXFR_BULK_IN(ep)	(0x00 | (ep))	/* bulk or interrupt */
319 #define MAX3421_HXFR_SETUP		 0x10
320 #define MAX3421_HXFR_BULK_OUT(ep)	(0x20 | (ep))	/* bulk or interrupt */
321 #define MAX3421_HXFR_ISO_IN(ep)		(0x40 | (ep))
322 #define MAX3421_HXFR_ISO_OUT(ep)	(0x60 | (ep))
323 #define MAX3421_HXFR_HS_IN		 0x80		/* handshake in */
324 #define MAX3421_HXFR_HS_OUT		 0xa0		/* handshake out */
325 
326 #define field(val, bit)	((val) << (bit))
327 
328 static inline s16
329 frame_diff(u16 left, u16 right)
330 {
331 	return ((unsigned) (left - right)) % (USB_MAX_FRAME_NUMBER + 1);
332 }
333 
334 static inline struct max3421_hcd *
335 hcd_to_max3421(struct usb_hcd *hcd)
336 {
337 	return (struct max3421_hcd *) hcd->hcd_priv;
338 }
339 
340 static inline struct usb_hcd *
341 max3421_to_hcd(struct max3421_hcd *max3421_hcd)
342 {
343 	return container_of((void *) max3421_hcd, struct usb_hcd, hcd_priv);
344 }
345 
346 static u8
347 spi_rd8(struct usb_hcd *hcd, unsigned int reg)
348 {
349 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
350 	struct spi_device *spi = to_spi_device(hcd->self.controller);
351 	struct spi_transfer transfer;
352 	struct spi_message msg;
353 
354 	memset(&transfer, 0, sizeof(transfer));
355 
356 	spi_message_init(&msg);
357 
358 	max3421_hcd->tx->data[0] =
359 		(field(reg, MAX3421_SPI_REG_SHIFT) |
360 		 field(MAX3421_SPI_DIR_RD, MAX3421_SPI_DIR_SHIFT));
361 
362 	transfer.tx_buf = max3421_hcd->tx->data;
363 	transfer.rx_buf = max3421_hcd->rx->data;
364 	transfer.len = 2;
365 
366 	spi_message_add_tail(&transfer, &msg);
367 	spi_sync(spi, &msg);
368 
369 	return max3421_hcd->rx->data[1];
370 }
371 
372 static void
373 spi_wr8(struct usb_hcd *hcd, unsigned int reg, u8 val)
374 {
375 	struct spi_device *spi = to_spi_device(hcd->self.controller);
376 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
377 	struct spi_transfer transfer;
378 	struct spi_message msg;
379 
380 	memset(&transfer, 0, sizeof(transfer));
381 
382 	spi_message_init(&msg);
383 
384 	max3421_hcd->tx->data[0] =
385 		(field(reg, MAX3421_SPI_REG_SHIFT) |
386 		 field(MAX3421_SPI_DIR_WR, MAX3421_SPI_DIR_SHIFT));
387 	max3421_hcd->tx->data[1] = val;
388 
389 	transfer.tx_buf = max3421_hcd->tx->data;
390 	transfer.len = 2;
391 
392 	spi_message_add_tail(&transfer, &msg);
393 	spi_sync(spi, &msg);
394 }
395 
396 static void
397 spi_rd_buf(struct usb_hcd *hcd, unsigned int reg, void *buf, size_t len)
398 {
399 	struct spi_device *spi = to_spi_device(hcd->self.controller);
400 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
401 	struct spi_transfer transfer[2];
402 	struct spi_message msg;
403 
404 	memset(transfer, 0, sizeof(transfer));
405 
406 	spi_message_init(&msg);
407 
408 	max3421_hcd->tx->data[0] =
409 		(field(reg, MAX3421_SPI_REG_SHIFT) |
410 		 field(MAX3421_SPI_DIR_RD, MAX3421_SPI_DIR_SHIFT));
411 	transfer[0].tx_buf = max3421_hcd->tx->data;
412 	transfer[0].len = 1;
413 
414 	transfer[1].rx_buf = buf;
415 	transfer[1].len = len;
416 
417 	spi_message_add_tail(&transfer[0], &msg);
418 	spi_message_add_tail(&transfer[1], &msg);
419 	spi_sync(spi, &msg);
420 }
421 
422 static void
423 spi_wr_buf(struct usb_hcd *hcd, unsigned int reg, void *buf, size_t len)
424 {
425 	struct spi_device *spi = to_spi_device(hcd->self.controller);
426 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
427 	struct spi_transfer transfer[2];
428 	struct spi_message msg;
429 
430 	memset(transfer, 0, sizeof(transfer));
431 
432 	spi_message_init(&msg);
433 
434 	max3421_hcd->tx->data[0] =
435 		(field(reg, MAX3421_SPI_REG_SHIFT) |
436 		 field(MAX3421_SPI_DIR_WR, MAX3421_SPI_DIR_SHIFT));
437 
438 	transfer[0].tx_buf = max3421_hcd->tx->data;
439 	transfer[0].len = 1;
440 
441 	transfer[1].tx_buf = buf;
442 	transfer[1].len = len;
443 
444 	spi_message_add_tail(&transfer[0], &msg);
445 	spi_message_add_tail(&transfer[1], &msg);
446 	spi_sync(spi, &msg);
447 }
448 
449 /*
450  * Figure out the correct setting for the LOWSPEED and HUBPRE mode
451  * bits.  The HUBPRE bit needs to be set when MAX3421E operates at
452  * full speed, but it's talking to a low-speed device (i.e., through a
453  * hub).  Setting that bit ensures that every low-speed packet is
454  * preceded by a full-speed PRE PID.  Possible configurations:
455  *
456  * Hub speed:	Device speed:	=>	LOWSPEED bit:	HUBPRE bit:
457  *	FULL	FULL		=>	0		0
458  *	FULL	LOW		=>	1		1
459  *	LOW	LOW		=>	1		0
460  *	LOW	FULL		=>	1		0
461  */
462 static void
463 max3421_set_speed(struct usb_hcd *hcd, struct usb_device *dev)
464 {
465 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
466 	u8 mode_lowspeed, mode_hubpre, mode = max3421_hcd->mode;
467 
468 	mode_lowspeed = BIT(MAX3421_MODE_LOWSPEED_BIT);
469 	mode_hubpre   = BIT(MAX3421_MODE_HUBPRE_BIT);
470 	if (max3421_hcd->port_status & USB_PORT_STAT_LOW_SPEED) {
471 		mode |=  mode_lowspeed;
472 		mode &= ~mode_hubpre;
473 	} else if (dev->speed == USB_SPEED_LOW) {
474 		mode |= mode_lowspeed | mode_hubpre;
475 	} else {
476 		mode &= ~(mode_lowspeed | mode_hubpre);
477 	}
478 	if (mode != max3421_hcd->mode) {
479 		max3421_hcd->mode = mode;
480 		spi_wr8(hcd, MAX3421_REG_MODE, max3421_hcd->mode);
481 	}
482 
483 }
484 
485 /*
486  * Caller must NOT hold HCD spinlock.
487  */
488 static void
489 max3421_set_address(struct usb_hcd *hcd, struct usb_device *dev, int epnum)
490 {
491 	int rcvtog, sndtog;
492 	u8 hctl;
493 
494 	/* setup new endpoint's toggle bits: */
495 	rcvtog = usb_gettoggle(dev, epnum, 0);
496 	sndtog = usb_gettoggle(dev, epnum, 1);
497 	hctl = (BIT(rcvtog + MAX3421_HCTL_RCVTOG0_BIT) |
498 		BIT(sndtog + MAX3421_HCTL_SNDTOG0_BIT));
499 
500 	spi_wr8(hcd, MAX3421_REG_HCTL, hctl);
501 
502 	/*
503 	 * Note: devnum for one and the same device can change during
504 	 * address-assignment so it's best to just always load the
505 	 * address whenever the end-point changed/was forced.
506 	 */
507 	spi_wr8(hcd, MAX3421_REG_PERADDR, dev->devnum);
508 }
509 
510 static int
511 max3421_ctrl_setup(struct usb_hcd *hcd, struct urb *urb)
512 {
513 	spi_wr_buf(hcd, MAX3421_REG_SUDFIFO, urb->setup_packet, 8);
514 	return MAX3421_HXFR_SETUP;
515 }
516 
517 static int
518 max3421_transfer_in(struct usb_hcd *hcd, struct urb *urb)
519 {
520 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
521 	int epnum = usb_pipeendpoint(urb->pipe);
522 
523 	max3421_hcd->curr_len = 0;
524 	max3421_hcd->hien |= BIT(MAX3421_HI_RCVDAV_BIT);
525 	return MAX3421_HXFR_BULK_IN(epnum);
526 }
527 
528 static int
529 max3421_transfer_out(struct usb_hcd *hcd, struct urb *urb, int fast_retransmit)
530 {
531 	struct spi_device *spi = to_spi_device(hcd->self.controller);
532 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
533 	int epnum = usb_pipeendpoint(urb->pipe);
534 	u32 max_packet;
535 	void *src;
536 
537 	src = urb->transfer_buffer + urb->actual_length;
538 
539 	if (fast_retransmit) {
540 		if (max3421_hcd->rev == 0x12) {
541 			/* work around rev 0x12 bug: */
542 			spi_wr8(hcd, MAX3421_REG_SNDBC, 0);
543 			spi_wr8(hcd, MAX3421_REG_SNDFIFO, ((u8 *) src)[0]);
544 			spi_wr8(hcd, MAX3421_REG_SNDBC, max3421_hcd->curr_len);
545 		}
546 		return MAX3421_HXFR_BULK_OUT(epnum);
547 	}
548 
549 	max_packet = usb_maxpacket(urb->dev, urb->pipe);
550 
551 	if (max_packet > MAX3421_FIFO_SIZE) {
552 		/*
553 		 * We do not support isochronous transfers at this
554 		 * time.
555 		 */
556 		dev_err(&spi->dev,
557 			"%s: packet-size of %u too big (limit is %u bytes)",
558 			__func__, max_packet, MAX3421_FIFO_SIZE);
559 		max3421_hcd->urb_done = -EMSGSIZE;
560 		return -EMSGSIZE;
561 	}
562 	max3421_hcd->curr_len = min((urb->transfer_buffer_length -
563 				     urb->actual_length), max_packet);
564 
565 	spi_wr_buf(hcd, MAX3421_REG_SNDFIFO, src, max3421_hcd->curr_len);
566 	spi_wr8(hcd, MAX3421_REG_SNDBC, max3421_hcd->curr_len);
567 	return MAX3421_HXFR_BULK_OUT(epnum);
568 }
569 
570 /*
571  * Issue the next host-transfer command.
572  * Caller must NOT hold HCD spinlock.
573  */
574 static void
575 max3421_next_transfer(struct usb_hcd *hcd, int fast_retransmit)
576 {
577 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
578 	struct urb *urb = max3421_hcd->curr_urb;
579 	struct max3421_ep *max3421_ep;
580 	int cmd = -EINVAL;
581 
582 	if (!urb)
583 		return;	/* nothing to do */
584 
585 	max3421_ep = urb->ep->hcpriv;
586 
587 	switch (max3421_ep->pkt_state) {
588 	case PKT_STATE_SETUP:
589 		cmd = max3421_ctrl_setup(hcd, urb);
590 		break;
591 
592 	case PKT_STATE_TRANSFER:
593 		if (usb_urb_dir_in(urb))
594 			cmd = max3421_transfer_in(hcd, urb);
595 		else
596 			cmd = max3421_transfer_out(hcd, urb, fast_retransmit);
597 		break;
598 
599 	case PKT_STATE_TERMINATE:
600 		/*
601 		 * IN transfers are terminated with HS_OUT token,
602 		 * OUT transfers with HS_IN:
603 		 */
604 		if (usb_urb_dir_in(urb))
605 			cmd = MAX3421_HXFR_HS_OUT;
606 		else
607 			cmd = MAX3421_HXFR_HS_IN;
608 		break;
609 	}
610 
611 	if (cmd < 0)
612 		return;
613 
614 	/* issue the command and wait for host-xfer-done interrupt: */
615 
616 	spi_wr8(hcd, MAX3421_REG_HXFR, cmd);
617 	max3421_hcd->hien |= BIT(MAX3421_HI_HXFRDN_BIT);
618 }
619 
620 /*
621  * Find the next URB to process and start its execution.
622  *
623  * At this time, we do not anticipate ever connecting a USB hub to the
624  * MAX3421 chip, so at most USB device can be connected and we can use
625  * a simplistic scheduler: at the start of a frame, schedule all
626  * periodic transfers.  Once that is done, use the remainder of the
627  * frame to process non-periodic (bulk & control) transfers.
628  *
629  * Preconditions:
630  * o Caller must NOT hold HCD spinlock.
631  * o max3421_hcd->curr_urb MUST BE NULL.
632  * o MAX3421E chip must be idle.
633  */
634 static int
635 max3421_select_and_start_urb(struct usb_hcd *hcd)
636 {
637 	struct spi_device *spi = to_spi_device(hcd->self.controller);
638 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
639 	struct urb *urb, *curr_urb = NULL;
640 	struct max3421_ep *max3421_ep;
641 	int epnum;
642 	struct usb_host_endpoint *ep;
643 	struct list_head *pos;
644 	unsigned long flags;
645 
646 	spin_lock_irqsave(&max3421_hcd->lock, flags);
647 
648 	for (;
649 	     max3421_hcd->sched_pass < SCHED_PASS_DONE;
650 	     ++max3421_hcd->sched_pass)
651 		list_for_each(pos, &max3421_hcd->ep_list) {
652 			urb = NULL;
653 			max3421_ep = container_of(pos, struct max3421_ep,
654 						  ep_list);
655 			ep = max3421_ep->ep;
656 
657 			switch (usb_endpoint_type(&ep->desc)) {
658 			case USB_ENDPOINT_XFER_ISOC:
659 			case USB_ENDPOINT_XFER_INT:
660 				if (max3421_hcd->sched_pass !=
661 				    SCHED_PASS_PERIODIC)
662 					continue;
663 				break;
664 
665 			case USB_ENDPOINT_XFER_CONTROL:
666 			case USB_ENDPOINT_XFER_BULK:
667 				if (max3421_hcd->sched_pass !=
668 				    SCHED_PASS_NON_PERIODIC)
669 					continue;
670 				break;
671 			}
672 
673 			if (list_empty(&ep->urb_list))
674 				continue;	/* nothing to do */
675 			urb = list_first_entry(&ep->urb_list, struct urb,
676 					       urb_list);
677 			if (urb->unlinked) {
678 				dev_dbg(&spi->dev, "%s: URB %p unlinked=%d",
679 					__func__, urb, urb->unlinked);
680 				max3421_hcd->curr_urb = urb;
681 				max3421_hcd->urb_done = 1;
682 				spin_unlock_irqrestore(&max3421_hcd->lock,
683 						       flags);
684 				return 1;
685 			}
686 
687 			switch (usb_endpoint_type(&ep->desc)) {
688 			case USB_ENDPOINT_XFER_CONTROL:
689 				/*
690 				 * Allow one control transaction per
691 				 * frame per endpoint:
692 				 */
693 				if (frame_diff(max3421_ep->last_active,
694 					       max3421_hcd->frame_number) == 0)
695 					continue;
696 				break;
697 
698 			case USB_ENDPOINT_XFER_BULK:
699 				if (max3421_ep->retransmit
700 				    && (frame_diff(max3421_ep->last_active,
701 						   max3421_hcd->frame_number)
702 					== 0))
703 					/*
704 					 * We already tried this EP
705 					 * during this frame and got a
706 					 * NAK or error; wait for next frame
707 					 */
708 					continue;
709 				break;
710 
711 			case USB_ENDPOINT_XFER_ISOC:
712 			case USB_ENDPOINT_XFER_INT:
713 				if (frame_diff(max3421_hcd->frame_number,
714 					       max3421_ep->last_active)
715 				    < urb->interval)
716 					/*
717 					 * We already processed this
718 					 * end-point in the current
719 					 * frame
720 					 */
721 					continue;
722 				break;
723 			}
724 
725 			/* move current ep to tail: */
726 			list_move_tail(pos, &max3421_hcd->ep_list);
727 			curr_urb = urb;
728 			goto done;
729 		}
730 done:
731 	if (!curr_urb) {
732 		spin_unlock_irqrestore(&max3421_hcd->lock, flags);
733 		return 0;
734 	}
735 
736 	urb = max3421_hcd->curr_urb = curr_urb;
737 	epnum = usb_endpoint_num(&urb->ep->desc);
738 	if (max3421_ep->retransmit)
739 		/* restart (part of) a USB transaction: */
740 		max3421_ep->retransmit = 0;
741 	else {
742 		/* start USB transaction: */
743 		if (usb_endpoint_xfer_control(&ep->desc)) {
744 			/*
745 			 * See USB 2.0 spec section 8.6.1
746 			 * Initialization via SETUP Token:
747 			 */
748 			usb_settoggle(urb->dev, epnum, 0, 1);
749 			usb_settoggle(urb->dev, epnum, 1, 1);
750 			max3421_ep->pkt_state = PKT_STATE_SETUP;
751 		} else
752 			max3421_ep->pkt_state = PKT_STATE_TRANSFER;
753 	}
754 
755 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
756 
757 	max3421_ep->last_active = max3421_hcd->frame_number;
758 	max3421_set_address(hcd, urb->dev, epnum);
759 	max3421_set_speed(hcd, urb->dev);
760 	max3421_next_transfer(hcd, 0);
761 	return 1;
762 }
763 
764 /*
765  * Check all endpoints for URBs that got unlinked.
766  *
767  * Caller must NOT hold HCD spinlock.
768  */
769 static int
770 max3421_check_unlink(struct usb_hcd *hcd)
771 {
772 	struct spi_device *spi = to_spi_device(hcd->self.controller);
773 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
774 	struct max3421_ep *max3421_ep;
775 	struct usb_host_endpoint *ep;
776 	struct urb *urb, *next;
777 	unsigned long flags;
778 	int retval = 0;
779 
780 	spin_lock_irqsave(&max3421_hcd->lock, flags);
781 	list_for_each_entry(max3421_ep, &max3421_hcd->ep_list, ep_list) {
782 		ep = max3421_ep->ep;
783 		list_for_each_entry_safe(urb, next, &ep->urb_list, urb_list) {
784 			if (urb->unlinked) {
785 				retval = 1;
786 				dev_dbg(&spi->dev, "%s: URB %p unlinked=%d",
787 					__func__, urb, urb->unlinked);
788 				usb_hcd_unlink_urb_from_ep(hcd, urb);
789 				spin_unlock_irqrestore(&max3421_hcd->lock,
790 						       flags);
791 				usb_hcd_giveback_urb(hcd, urb, 0);
792 				spin_lock_irqsave(&max3421_hcd->lock, flags);
793 			}
794 		}
795 	}
796 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
797 	return retval;
798 }
799 
800 /*
801  * Caller must NOT hold HCD spinlock.
802  */
803 static void
804 max3421_slow_retransmit(struct usb_hcd *hcd)
805 {
806 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
807 	struct urb *urb = max3421_hcd->curr_urb;
808 	struct max3421_ep *max3421_ep;
809 
810 	max3421_ep = urb->ep->hcpriv;
811 	max3421_ep->retransmit = 1;
812 	max3421_hcd->curr_urb = NULL;
813 }
814 
815 /*
816  * Caller must NOT hold HCD spinlock.
817  */
818 static void
819 max3421_recv_data_available(struct usb_hcd *hcd)
820 {
821 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
822 	struct urb *urb = max3421_hcd->curr_urb;
823 	size_t remaining, transfer_size;
824 	u8 rcvbc;
825 
826 	rcvbc = spi_rd8(hcd, MAX3421_REG_RCVBC);
827 
828 	if (rcvbc > MAX3421_FIFO_SIZE)
829 		rcvbc = MAX3421_FIFO_SIZE;
830 	if (urb->actual_length >= urb->transfer_buffer_length)
831 		remaining = 0;
832 	else
833 		remaining = urb->transfer_buffer_length - urb->actual_length;
834 	transfer_size = rcvbc;
835 	if (transfer_size > remaining)
836 		transfer_size = remaining;
837 	if (transfer_size > 0) {
838 		void *dst = urb->transfer_buffer + urb->actual_length;
839 
840 		spi_rd_buf(hcd, MAX3421_REG_RCVFIFO, dst, transfer_size);
841 		urb->actual_length += transfer_size;
842 		max3421_hcd->curr_len = transfer_size;
843 	}
844 
845 	/* ack the RCVDAV irq now that the FIFO has been read: */
846 	spi_wr8(hcd, MAX3421_REG_HIRQ, BIT(MAX3421_HI_RCVDAV_BIT));
847 }
848 
849 static void
850 max3421_handle_error(struct usb_hcd *hcd, u8 hrsl)
851 {
852 	struct spi_device *spi = to_spi_device(hcd->self.controller);
853 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
854 	u8 result_code = hrsl & MAX3421_HRSL_RESULT_MASK;
855 	struct urb *urb = max3421_hcd->curr_urb;
856 	struct max3421_ep *max3421_ep = urb->ep->hcpriv;
857 	int switch_sndfifo;
858 
859 	/*
860 	 * If an OUT command results in any response other than OK
861 	 * (i.e., error or NAK), we have to perform a dummy-write to
862 	 * SNDBC so the FIFO gets switched back to us.  Otherwise, we
863 	 * get out of sync with the SNDFIFO double buffer.
864 	 */
865 	switch_sndfifo = (max3421_ep->pkt_state == PKT_STATE_TRANSFER &&
866 			  usb_urb_dir_out(urb));
867 
868 	switch (result_code) {
869 	case MAX3421_HRSL_OK:
870 		return;			/* this shouldn't happen */
871 
872 	case MAX3421_HRSL_WRONGPID:	/* received wrong PID */
873 	case MAX3421_HRSL_BUSY:		/* SIE busy */
874 	case MAX3421_HRSL_BADREQ:	/* bad val in HXFR */
875 	case MAX3421_HRSL_UNDEF:	/* reserved */
876 	case MAX3421_HRSL_KERR:		/* K-state instead of response */
877 	case MAX3421_HRSL_JERR:		/* J-state instead of response */
878 		/*
879 		 * packet experienced an error that we cannot recover
880 		 * from; report error
881 		 */
882 		max3421_hcd->urb_done = hrsl_to_error[result_code];
883 		dev_dbg(&spi->dev, "%s: unexpected error HRSL=0x%02x",
884 			__func__, hrsl);
885 		break;
886 
887 	case MAX3421_HRSL_TOGERR:
888 		if (usb_urb_dir_in(urb))
889 			; /* don't do anything (device will switch toggle) */
890 		else {
891 			/* flip the send toggle bit: */
892 			int sndtog = (hrsl >> MAX3421_HRSL_SNDTOGRD_BIT) & 1;
893 
894 			sndtog ^= 1;
895 			spi_wr8(hcd, MAX3421_REG_HCTL,
896 				BIT(sndtog + MAX3421_HCTL_SNDTOG0_BIT));
897 		}
898 		fallthrough;
899 	case MAX3421_HRSL_BADBC:	/* bad byte count */
900 	case MAX3421_HRSL_PIDERR:	/* received PID is corrupted */
901 	case MAX3421_HRSL_PKTERR:	/* packet error (stuff, EOP) */
902 	case MAX3421_HRSL_CRCERR:	/* CRC error */
903 	case MAX3421_HRSL_BABBLE:	/* device talked too long */
904 	case MAX3421_HRSL_TIMEOUT:
905 		if (max3421_ep->retries++ < USB_MAX_RETRIES)
906 			/* retry the packet again in the next frame */
907 			max3421_slow_retransmit(hcd);
908 		else {
909 			/* Based on ohci.h cc_to_err[]: */
910 			max3421_hcd->urb_done = hrsl_to_error[result_code];
911 			dev_dbg(&spi->dev, "%s: unexpected error HRSL=0x%02x",
912 				__func__, hrsl);
913 		}
914 		break;
915 
916 	case MAX3421_HRSL_STALL:
917 		dev_dbg(&spi->dev, "%s: unexpected error HRSL=0x%02x",
918 			__func__, hrsl);
919 		max3421_hcd->urb_done = hrsl_to_error[result_code];
920 		break;
921 
922 	case MAX3421_HRSL_NAK:
923 		/*
924 		 * Device wasn't ready for data or has no data
925 		 * available: retry the packet again.
926 		 */
927 		if (max3421_ep->naks++ < NAK_MAX_FAST_RETRANSMITS) {
928 			max3421_next_transfer(hcd, 1);
929 			switch_sndfifo = 0;
930 		} else
931 			max3421_slow_retransmit(hcd);
932 		break;
933 	}
934 	if (switch_sndfifo)
935 		spi_wr8(hcd, MAX3421_REG_SNDBC, 0);
936 }
937 
938 /*
939  * Caller must NOT hold HCD spinlock.
940  */
941 static int
942 max3421_transfer_in_done(struct usb_hcd *hcd, struct urb *urb)
943 {
944 	struct spi_device *spi = to_spi_device(hcd->self.controller);
945 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
946 	u32 max_packet;
947 
948 	if (urb->actual_length >= urb->transfer_buffer_length)
949 		return 1;	/* read is complete, so we're done */
950 
951 	/*
952 	 * USB 2.0 Section 5.3.2 Pipes: packets must be full size
953 	 * except for last one.
954 	 */
955 	max_packet = usb_maxpacket(urb->dev, urb->pipe);
956 	if (max_packet > MAX3421_FIFO_SIZE) {
957 		/*
958 		 * We do not support isochronous transfers at this
959 		 * time...
960 		 */
961 		dev_err(&spi->dev,
962 			"%s: packet-size of %u too big (limit is %u bytes)",
963 			__func__, max_packet, MAX3421_FIFO_SIZE);
964 		return -EINVAL;
965 	}
966 
967 	if (max3421_hcd->curr_len < max_packet) {
968 		if (urb->transfer_flags & URB_SHORT_NOT_OK) {
969 			/*
970 			 * remaining > 0 and received an
971 			 * unexpected partial packet ->
972 			 * error
973 			 */
974 			return -EREMOTEIO;
975 		} else
976 			/* short read, but it's OK */
977 			return 1;
978 	}
979 	return 0;	/* not done */
980 }
981 
982 /*
983  * Caller must NOT hold HCD spinlock.
984  */
985 static int
986 max3421_transfer_out_done(struct usb_hcd *hcd, struct urb *urb)
987 {
988 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
989 
990 	urb->actual_length += max3421_hcd->curr_len;
991 	if (urb->actual_length < urb->transfer_buffer_length)
992 		return 0;
993 	if (urb->transfer_flags & URB_ZERO_PACKET) {
994 		/*
995 		 * Some hardware needs a zero-size packet at the end
996 		 * of a bulk-out transfer if the last transfer was a
997 		 * full-sized packet (i.e., such hardware use <
998 		 * max_packet as an indicator that the end of the
999 		 * packet has been reached).
1000 		 */
1001 		u32 max_packet = usb_maxpacket(urb->dev, urb->pipe);
1002 
1003 		if (max3421_hcd->curr_len == max_packet)
1004 			return 0;
1005 	}
1006 	return 1;
1007 }
1008 
1009 /*
1010  * Caller must NOT hold HCD spinlock.
1011  */
1012 static void
1013 max3421_host_transfer_done(struct usb_hcd *hcd)
1014 {
1015 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1016 	struct urb *urb = max3421_hcd->curr_urb;
1017 	struct max3421_ep *max3421_ep;
1018 	u8 result_code, hrsl;
1019 	int urb_done = 0;
1020 
1021 	max3421_hcd->hien &= ~(BIT(MAX3421_HI_HXFRDN_BIT) |
1022 			       BIT(MAX3421_HI_RCVDAV_BIT));
1023 
1024 	hrsl = spi_rd8(hcd, MAX3421_REG_HRSL);
1025 	result_code = hrsl & MAX3421_HRSL_RESULT_MASK;
1026 
1027 #ifdef DEBUG
1028 	++max3421_hcd->err_stat[result_code];
1029 #endif
1030 
1031 	max3421_ep = urb->ep->hcpriv;
1032 
1033 	if (unlikely(result_code != MAX3421_HRSL_OK)) {
1034 		max3421_handle_error(hcd, hrsl);
1035 		return;
1036 	}
1037 
1038 	max3421_ep->naks = 0;
1039 	max3421_ep->retries = 0;
1040 	switch (max3421_ep->pkt_state) {
1041 
1042 	case PKT_STATE_SETUP:
1043 		if (urb->transfer_buffer_length > 0)
1044 			max3421_ep->pkt_state = PKT_STATE_TRANSFER;
1045 		else
1046 			max3421_ep->pkt_state = PKT_STATE_TERMINATE;
1047 		break;
1048 
1049 	case PKT_STATE_TRANSFER:
1050 		if (usb_urb_dir_in(urb))
1051 			urb_done = max3421_transfer_in_done(hcd, urb);
1052 		else
1053 			urb_done = max3421_transfer_out_done(hcd, urb);
1054 		if (urb_done > 0 && usb_pipetype(urb->pipe) == PIPE_CONTROL) {
1055 			/*
1056 			 * We aren't really done - we still need to
1057 			 * terminate the control transfer:
1058 			 */
1059 			max3421_hcd->urb_done = urb_done = 0;
1060 			max3421_ep->pkt_state = PKT_STATE_TERMINATE;
1061 		}
1062 		break;
1063 
1064 	case PKT_STATE_TERMINATE:
1065 		urb_done = 1;
1066 		break;
1067 	}
1068 
1069 	if (urb_done)
1070 		max3421_hcd->urb_done = urb_done;
1071 	else
1072 		max3421_next_transfer(hcd, 0);
1073 }
1074 
1075 /*
1076  * Caller must NOT hold HCD spinlock.
1077  */
1078 static void
1079 max3421_detect_conn(struct usb_hcd *hcd)
1080 {
1081 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1082 	unsigned int jk, have_conn = 0;
1083 	u32 old_port_status, chg;
1084 	unsigned long flags;
1085 	u8 hrsl, mode;
1086 
1087 	hrsl = spi_rd8(hcd, MAX3421_REG_HRSL);
1088 
1089 	jk = ((((hrsl >> MAX3421_HRSL_JSTATUS_BIT) & 1) << 0) |
1090 	      (((hrsl >> MAX3421_HRSL_KSTATUS_BIT) & 1) << 1));
1091 
1092 	mode = max3421_hcd->mode;
1093 
1094 	switch (jk) {
1095 	case 0x0: /* SE0: disconnect */
1096 		/*
1097 		 * Turn off SOFKAENAB bit to avoid getting interrupt
1098 		 * every milli-second:
1099 		 */
1100 		mode &= ~BIT(MAX3421_MODE_SOFKAENAB_BIT);
1101 		break;
1102 
1103 	case 0x1: /* J=0,K=1: low-speed (in full-speed or vice versa) */
1104 	case 0x2: /* J=1,K=0: full-speed (in full-speed or vice versa) */
1105 		if (jk == 0x2)
1106 			/* need to switch to the other speed: */
1107 			mode ^= BIT(MAX3421_MODE_LOWSPEED_BIT);
1108 		/* turn on SOFKAENAB bit: */
1109 		mode |= BIT(MAX3421_MODE_SOFKAENAB_BIT);
1110 		have_conn = 1;
1111 		break;
1112 
1113 	case 0x3: /* illegal */
1114 		break;
1115 	}
1116 
1117 	max3421_hcd->mode = mode;
1118 	spi_wr8(hcd, MAX3421_REG_MODE, max3421_hcd->mode);
1119 
1120 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1121 	old_port_status = max3421_hcd->port_status;
1122 	if (have_conn)
1123 		max3421_hcd->port_status |=  USB_PORT_STAT_CONNECTION;
1124 	else
1125 		max3421_hcd->port_status &= ~USB_PORT_STAT_CONNECTION;
1126 	if (mode & BIT(MAX3421_MODE_LOWSPEED_BIT))
1127 		max3421_hcd->port_status |=  USB_PORT_STAT_LOW_SPEED;
1128 	else
1129 		max3421_hcd->port_status &= ~USB_PORT_STAT_LOW_SPEED;
1130 	chg = (old_port_status ^ max3421_hcd->port_status);
1131 	max3421_hcd->port_status |= chg << 16;
1132 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1133 }
1134 
1135 static irqreturn_t
1136 max3421_irq_handler(int irq, void *dev_id)
1137 {
1138 	struct usb_hcd *hcd = dev_id;
1139 	struct spi_device *spi = to_spi_device(hcd->self.controller);
1140 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1141 
1142 	if (max3421_hcd->spi_thread)
1143 		wake_up_process(max3421_hcd->spi_thread);
1144 	if (!test_and_set_bit(ENABLE_IRQ, &max3421_hcd->todo))
1145 		disable_irq_nosync(spi->irq);
1146 	return IRQ_HANDLED;
1147 }
1148 
1149 #ifdef DEBUG
1150 
1151 static void
1152 dump_eps(struct usb_hcd *hcd)
1153 {
1154 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1155 	struct max3421_ep *max3421_ep;
1156 	struct usb_host_endpoint *ep;
1157 	char ubuf[512], *dp, *end;
1158 	unsigned long flags;
1159 	struct urb *urb;
1160 	int epnum, ret;
1161 
1162 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1163 	list_for_each_entry(max3421_ep, &max3421_hcd->ep_list, ep_list) {
1164 		ep = max3421_ep->ep;
1165 
1166 		dp = ubuf;
1167 		end = dp + sizeof(ubuf);
1168 		*dp = '\0';
1169 		list_for_each_entry(urb, &ep->urb_list, urb_list) {
1170 			ret = snprintf(dp, end - dp, " %p(%d.%s %d/%d)", urb,
1171 				       usb_pipetype(urb->pipe),
1172 				       usb_urb_dir_in(urb) ? "IN" : "OUT",
1173 				       urb->actual_length,
1174 				       urb->transfer_buffer_length);
1175 			if (ret < 0 || ret >= end - dp)
1176 				break;	/* error or buffer full */
1177 			dp += ret;
1178 		}
1179 
1180 		epnum = usb_endpoint_num(&ep->desc);
1181 		pr_info("EP%0u %u lst %04u rtr %u nak %6u rxmt %u: %s\n",
1182 			epnum, max3421_ep->pkt_state, max3421_ep->last_active,
1183 			max3421_ep->retries, max3421_ep->naks,
1184 			max3421_ep->retransmit, ubuf);
1185 	}
1186 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1187 }
1188 
1189 #endif /* DEBUG */
1190 
1191 /* Return zero if no work was performed, 1 otherwise.  */
1192 static int
1193 max3421_handle_irqs(struct usb_hcd *hcd)
1194 {
1195 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1196 	u32 chg, old_port_status;
1197 	unsigned long flags;
1198 	u8 hirq;
1199 
1200 	/*
1201 	 * Read and ack pending interrupts (CPU must never
1202 	 * clear SNDBAV directly and RCVDAV must be cleared by
1203 	 * max3421_recv_data_available()!):
1204 	 */
1205 	hirq = spi_rd8(hcd, MAX3421_REG_HIRQ);
1206 	hirq &= max3421_hcd->hien;
1207 	if (!hirq)
1208 		return 0;
1209 
1210 	spi_wr8(hcd, MAX3421_REG_HIRQ,
1211 		hirq & ~(BIT(MAX3421_HI_SNDBAV_BIT) |
1212 			 BIT(MAX3421_HI_RCVDAV_BIT)));
1213 
1214 	if (hirq & BIT(MAX3421_HI_FRAME_BIT)) {
1215 		max3421_hcd->frame_number = ((max3421_hcd->frame_number + 1)
1216 					     & USB_MAX_FRAME_NUMBER);
1217 		max3421_hcd->sched_pass = SCHED_PASS_PERIODIC;
1218 	}
1219 
1220 	if (hirq & BIT(MAX3421_HI_RCVDAV_BIT))
1221 		max3421_recv_data_available(hcd);
1222 
1223 	if (hirq & BIT(MAX3421_HI_HXFRDN_BIT))
1224 		max3421_host_transfer_done(hcd);
1225 
1226 	if (hirq & BIT(MAX3421_HI_CONDET_BIT))
1227 		max3421_detect_conn(hcd);
1228 
1229 	/*
1230 	 * Now process interrupts that may affect HCD state
1231 	 * other than the end-points:
1232 	 */
1233 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1234 
1235 	old_port_status = max3421_hcd->port_status;
1236 	if (hirq & BIT(MAX3421_HI_BUSEVENT_BIT)) {
1237 		if (max3421_hcd->port_status & USB_PORT_STAT_RESET) {
1238 			/* BUSEVENT due to completion of Bus Reset */
1239 			max3421_hcd->port_status &= ~USB_PORT_STAT_RESET;
1240 			max3421_hcd->port_status |=  USB_PORT_STAT_ENABLE;
1241 		} else {
1242 			/* BUSEVENT due to completion of Bus Resume */
1243 			pr_info("%s: BUSEVENT Bus Resume Done\n", __func__);
1244 		}
1245 	}
1246 	if (hirq & BIT(MAX3421_HI_RWU_BIT))
1247 		pr_info("%s: RWU\n", __func__);
1248 	if (hirq & BIT(MAX3421_HI_SUSDN_BIT))
1249 		pr_info("%s: SUSDN\n", __func__);
1250 
1251 	chg = (old_port_status ^ max3421_hcd->port_status);
1252 	max3421_hcd->port_status |= chg << 16;
1253 
1254 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1255 
1256 #ifdef DEBUG
1257 	{
1258 		static unsigned long last_time;
1259 		char sbuf[16 * 16], *dp, *end;
1260 		int i;
1261 
1262 		if (time_after(jiffies, last_time + 5*HZ)) {
1263 			dp = sbuf;
1264 			end = sbuf + sizeof(sbuf);
1265 			*dp = '\0';
1266 			for (i = 0; i < 16; ++i) {
1267 				int ret = snprintf(dp, end - dp, " %lu",
1268 						   max3421_hcd->err_stat[i]);
1269 				if (ret < 0 || ret >= end - dp)
1270 					break;	/* error or buffer full */
1271 				dp += ret;
1272 			}
1273 			pr_info("%s: hrsl_stats %s\n", __func__, sbuf);
1274 			memset(max3421_hcd->err_stat, 0,
1275 			       sizeof(max3421_hcd->err_stat));
1276 			last_time = jiffies;
1277 
1278 			dump_eps(hcd);
1279 		}
1280 	}
1281 #endif
1282 	return 1;
1283 }
1284 
1285 static int
1286 max3421_reset_hcd(struct usb_hcd *hcd)
1287 {
1288 	struct spi_device *spi = to_spi_device(hcd->self.controller);
1289 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1290 	int timeout;
1291 
1292 	/* perform a chip reset and wait for OSCIRQ signal to appear: */
1293 	spi_wr8(hcd, MAX3421_REG_USBCTL, BIT(MAX3421_USBCTL_CHIPRES_BIT));
1294 	/* clear reset: */
1295 	spi_wr8(hcd, MAX3421_REG_USBCTL, 0);
1296 	timeout = 1000;
1297 	while (1) {
1298 		if (spi_rd8(hcd, MAX3421_REG_USBIRQ)
1299 		    & BIT(MAX3421_USBIRQ_OSCOKIRQ_BIT))
1300 			break;
1301 		if (--timeout < 0) {
1302 			dev_err(&spi->dev,
1303 				"timed out waiting for oscillator OK signal");
1304 			return 1;
1305 		}
1306 		cond_resched();
1307 	}
1308 
1309 	/*
1310 	 * Turn on host mode, automatic generation of SOF packets, and
1311 	 * enable pull-down registers on DM/DP:
1312 	 */
1313 	max3421_hcd->mode = (BIT(MAX3421_MODE_HOST_BIT) |
1314 			     BIT(MAX3421_MODE_SOFKAENAB_BIT) |
1315 			     BIT(MAX3421_MODE_DMPULLDN_BIT) |
1316 			     BIT(MAX3421_MODE_DPPULLDN_BIT));
1317 	spi_wr8(hcd, MAX3421_REG_MODE, max3421_hcd->mode);
1318 
1319 	/* reset frame-number: */
1320 	max3421_hcd->frame_number = USB_MAX_FRAME_NUMBER;
1321 	spi_wr8(hcd, MAX3421_REG_HCTL, BIT(MAX3421_HCTL_FRMRST_BIT));
1322 
1323 	/* sample the state of the D+ and D- lines */
1324 	spi_wr8(hcd, MAX3421_REG_HCTL, BIT(MAX3421_HCTL_SAMPLEBUS_BIT));
1325 	max3421_detect_conn(hcd);
1326 
1327 	/* enable frame, connection-detected, and bus-event interrupts: */
1328 	max3421_hcd->hien = (BIT(MAX3421_HI_FRAME_BIT) |
1329 			     BIT(MAX3421_HI_CONDET_BIT) |
1330 			     BIT(MAX3421_HI_BUSEVENT_BIT));
1331 	spi_wr8(hcd, MAX3421_REG_HIEN, max3421_hcd->hien);
1332 
1333 	/* enable interrupts: */
1334 	spi_wr8(hcd, MAX3421_REG_CPUCTL, BIT(MAX3421_CPUCTL_IE_BIT));
1335 	return 1;
1336 }
1337 
1338 static int
1339 max3421_urb_done(struct usb_hcd *hcd)
1340 {
1341 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1342 	unsigned long flags;
1343 	struct urb *urb;
1344 	int status;
1345 
1346 	status = max3421_hcd->urb_done;
1347 	max3421_hcd->urb_done = 0;
1348 	if (status > 0)
1349 		status = 0;
1350 	urb = max3421_hcd->curr_urb;
1351 	if (urb) {
1352 		/* save the old end-points toggles: */
1353 		u8 hrsl = spi_rd8(hcd, MAX3421_REG_HRSL);
1354 		int rcvtog = (hrsl >> MAX3421_HRSL_RCVTOGRD_BIT) & 1;
1355 		int sndtog = (hrsl >> MAX3421_HRSL_SNDTOGRD_BIT) & 1;
1356 		int epnum = usb_endpoint_num(&urb->ep->desc);
1357 
1358 		/* no locking: HCD (i.e., we) own toggles, don't we? */
1359 		usb_settoggle(urb->dev, epnum, 0, rcvtog);
1360 		usb_settoggle(urb->dev, epnum, 1, sndtog);
1361 
1362 		max3421_hcd->curr_urb = NULL;
1363 		spin_lock_irqsave(&max3421_hcd->lock, flags);
1364 		usb_hcd_unlink_urb_from_ep(hcd, urb);
1365 		spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1366 
1367 		/* must be called without the HCD spinlock: */
1368 		usb_hcd_giveback_urb(hcd, urb, status);
1369 	}
1370 	return 1;
1371 }
1372 
1373 static int
1374 max3421_spi_thread(void *dev_id)
1375 {
1376 	struct usb_hcd *hcd = dev_id;
1377 	struct spi_device *spi = to_spi_device(hcd->self.controller);
1378 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1379 	int i, i_worked = 1;
1380 
1381 	/* set full-duplex SPI mode, low-active interrupt pin: */
1382 	spi_wr8(hcd, MAX3421_REG_PINCTL,
1383 		(BIT(MAX3421_PINCTL_FDUPSPI_BIT) |	/* full-duplex */
1384 		 BIT(MAX3421_PINCTL_INTLEVEL_BIT)));	/* low-active irq */
1385 
1386 	while (!kthread_should_stop()) {
1387 		max3421_hcd->rev = spi_rd8(hcd, MAX3421_REG_REVISION);
1388 		if (max3421_hcd->rev == 0x12 || max3421_hcd->rev == 0x13)
1389 			break;
1390 		dev_err(&spi->dev, "bad rev 0x%02x", max3421_hcd->rev);
1391 		msleep(10000);
1392 	}
1393 	dev_info(&spi->dev, "rev 0x%x, SPI clk %dHz, bpw %u, irq %d\n",
1394 		 max3421_hcd->rev, spi->max_speed_hz, spi->bits_per_word,
1395 		 spi->irq);
1396 
1397 	while (!kthread_should_stop()) {
1398 		if (!i_worked) {
1399 			/*
1400 			 * We'll be waiting for wakeups from the hard
1401 			 * interrupt handler, so now is a good time to
1402 			 * sync our hien with the chip:
1403 			 */
1404 			spi_wr8(hcd, MAX3421_REG_HIEN, max3421_hcd->hien);
1405 
1406 			set_current_state(TASK_INTERRUPTIBLE);
1407 			if (test_and_clear_bit(ENABLE_IRQ, &max3421_hcd->todo))
1408 				enable_irq(spi->irq);
1409 			schedule();
1410 			__set_current_state(TASK_RUNNING);
1411 		}
1412 
1413 		i_worked = 0;
1414 
1415 		if (max3421_hcd->urb_done)
1416 			i_worked |= max3421_urb_done(hcd);
1417 		else if (max3421_handle_irqs(hcd))
1418 			i_worked = 1;
1419 		else if (!max3421_hcd->curr_urb)
1420 			i_worked |= max3421_select_and_start_urb(hcd);
1421 
1422 		if (test_and_clear_bit(RESET_HCD, &max3421_hcd->todo))
1423 			/* reset the HCD: */
1424 			i_worked |= max3421_reset_hcd(hcd);
1425 		if (test_and_clear_bit(RESET_PORT, &max3421_hcd->todo)) {
1426 			/* perform a USB bus reset: */
1427 			spi_wr8(hcd, MAX3421_REG_HCTL,
1428 				BIT(MAX3421_HCTL_BUSRST_BIT));
1429 			i_worked = 1;
1430 		}
1431 		if (test_and_clear_bit(CHECK_UNLINK, &max3421_hcd->todo))
1432 			i_worked |= max3421_check_unlink(hcd);
1433 		if (test_and_clear_bit(IOPIN_UPDATE, &max3421_hcd->todo)) {
1434 			/*
1435 			 * IOPINS1/IOPINS2 do not auto-increment, so we can't
1436 			 * use spi_wr_buf().
1437 			 */
1438 			for (i = 0; i < ARRAY_SIZE(max3421_hcd->iopins); ++i) {
1439 				u8 val = spi_rd8(hcd, MAX3421_REG_IOPINS1);
1440 
1441 				val = ((val & 0xf0) |
1442 				       (max3421_hcd->iopins[i] & 0x0f));
1443 				spi_wr8(hcd, MAX3421_REG_IOPINS1 + i, val);
1444 				max3421_hcd->iopins[i] = val;
1445 			}
1446 			i_worked = 1;
1447 		}
1448 	}
1449 	set_current_state(TASK_RUNNING);
1450 	dev_info(&spi->dev, "SPI thread exiting");
1451 	return 0;
1452 }
1453 
1454 static int
1455 max3421_reset_port(struct usb_hcd *hcd)
1456 {
1457 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1458 
1459 	max3421_hcd->port_status &= ~(USB_PORT_STAT_ENABLE |
1460 				      USB_PORT_STAT_LOW_SPEED);
1461 	max3421_hcd->port_status |= USB_PORT_STAT_RESET;
1462 	set_bit(RESET_PORT, &max3421_hcd->todo);
1463 	wake_up_process(max3421_hcd->spi_thread);
1464 	return 0;
1465 }
1466 
1467 static int
1468 max3421_reset(struct usb_hcd *hcd)
1469 {
1470 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1471 
1472 	hcd->self.sg_tablesize = 0;
1473 	hcd->speed = HCD_USB2;
1474 	hcd->self.root_hub->speed = USB_SPEED_FULL;
1475 	set_bit(RESET_HCD, &max3421_hcd->todo);
1476 	wake_up_process(max3421_hcd->spi_thread);
1477 	return 0;
1478 }
1479 
1480 static int
1481 max3421_start(struct usb_hcd *hcd)
1482 {
1483 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1484 
1485 	spin_lock_init(&max3421_hcd->lock);
1486 	max3421_hcd->rh_state = MAX3421_RH_RUNNING;
1487 
1488 	INIT_LIST_HEAD(&max3421_hcd->ep_list);
1489 
1490 	hcd->power_budget = POWER_BUDGET;
1491 	hcd->state = HC_STATE_RUNNING;
1492 	hcd->uses_new_polling = 1;
1493 	return 0;
1494 }
1495 
1496 static void
1497 max3421_stop(struct usb_hcd *hcd)
1498 {
1499 }
1500 
1501 static int
1502 max3421_urb_enqueue(struct usb_hcd *hcd, struct urb *urb, gfp_t mem_flags)
1503 {
1504 	struct spi_device *spi = to_spi_device(hcd->self.controller);
1505 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1506 	struct max3421_ep *max3421_ep;
1507 	unsigned long flags;
1508 	int retval;
1509 
1510 	switch (usb_pipetype(urb->pipe)) {
1511 	case PIPE_INTERRUPT:
1512 	case PIPE_ISOCHRONOUS:
1513 		if (urb->interval < 0) {
1514 			dev_err(&spi->dev,
1515 			  "%s: interval=%d for intr-/iso-pipe; expected > 0\n",
1516 				__func__, urb->interval);
1517 			return -EINVAL;
1518 		}
1519 		break;
1520 	default:
1521 		break;
1522 	}
1523 
1524 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1525 
1526 	max3421_ep = urb->ep->hcpriv;
1527 	if (!max3421_ep) {
1528 		/* gets freed in max3421_endpoint_disable: */
1529 		max3421_ep = kzalloc(sizeof(struct max3421_ep), GFP_ATOMIC);
1530 		if (!max3421_ep) {
1531 			retval = -ENOMEM;
1532 			goto out;
1533 		}
1534 		max3421_ep->ep = urb->ep;
1535 		max3421_ep->last_active = max3421_hcd->frame_number;
1536 		urb->ep->hcpriv = max3421_ep;
1537 
1538 		list_add_tail(&max3421_ep->ep_list, &max3421_hcd->ep_list);
1539 	}
1540 
1541 	retval = usb_hcd_link_urb_to_ep(hcd, urb);
1542 	if (retval == 0) {
1543 		/* Since we added to the queue, restart scheduling: */
1544 		max3421_hcd->sched_pass = SCHED_PASS_PERIODIC;
1545 		wake_up_process(max3421_hcd->spi_thread);
1546 	}
1547 
1548 out:
1549 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1550 	return retval;
1551 }
1552 
1553 static int
1554 max3421_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
1555 {
1556 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1557 	unsigned long flags;
1558 	int retval;
1559 
1560 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1561 
1562 	/*
1563 	 * This will set urb->unlinked which in turn causes the entry
1564 	 * to be dropped at the next opportunity.
1565 	 */
1566 	retval = usb_hcd_check_unlink_urb(hcd, urb, status);
1567 	if (retval == 0) {
1568 		set_bit(CHECK_UNLINK, &max3421_hcd->todo);
1569 		wake_up_process(max3421_hcd->spi_thread);
1570 	}
1571 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1572 	return retval;
1573 }
1574 
1575 static void
1576 max3421_endpoint_disable(struct usb_hcd *hcd, struct usb_host_endpoint *ep)
1577 {
1578 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1579 	unsigned long flags;
1580 
1581 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1582 
1583 	if (ep->hcpriv) {
1584 		struct max3421_ep *max3421_ep = ep->hcpriv;
1585 
1586 		/* remove myself from the ep_list: */
1587 		if (!list_empty(&max3421_ep->ep_list))
1588 			list_del(&max3421_ep->ep_list);
1589 		kfree(max3421_ep);
1590 		ep->hcpriv = NULL;
1591 	}
1592 
1593 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1594 }
1595 
1596 static int
1597 max3421_get_frame_number(struct usb_hcd *hcd)
1598 {
1599 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1600 	return max3421_hcd->frame_number;
1601 }
1602 
1603 /*
1604  * Should return a non-zero value when any port is undergoing a resume
1605  * transition while the root hub is suspended.
1606  */
1607 static int
1608 max3421_hub_status_data(struct usb_hcd *hcd, char *buf)
1609 {
1610 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1611 	unsigned long flags;
1612 	int retval = 0;
1613 
1614 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1615 	if (!HCD_HW_ACCESSIBLE(hcd))
1616 		goto done;
1617 
1618 	*buf = 0;
1619 	if ((max3421_hcd->port_status & PORT_C_MASK) != 0) {
1620 		*buf = (1 << 1); /* a hub over-current condition exists */
1621 		dev_dbg(hcd->self.controller,
1622 			"port status 0x%08x has changes\n",
1623 			max3421_hcd->port_status);
1624 		retval = 1;
1625 		if (max3421_hcd->rh_state == MAX3421_RH_SUSPENDED)
1626 			usb_hcd_resume_root_hub(hcd);
1627 	}
1628 done:
1629 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1630 	return retval;
1631 }
1632 
1633 static inline void
1634 hub_descriptor(struct usb_hub_descriptor *desc)
1635 {
1636 	memset(desc, 0, sizeof(*desc));
1637 	/*
1638 	 * See Table 11-13: Hub Descriptor in USB 2.0 spec.
1639 	 */
1640 	desc->bDescriptorType = USB_DT_HUB; /* hub descriptor */
1641 	desc->bDescLength = 9;
1642 	desc->wHubCharacteristics = cpu_to_le16(HUB_CHAR_INDV_PORT_LPSM |
1643 						HUB_CHAR_COMMON_OCPM);
1644 	desc->bNbrPorts = 1;
1645 }
1646 
1647 /*
1648  * Set the MAX3421E general-purpose output with number PIN_NUMBER to
1649  * VALUE (0 or 1).  PIN_NUMBER may be in the range from 1-8.  For
1650  * any other value, this function acts as a no-op.
1651  */
1652 static void
1653 max3421_gpout_set_value(struct usb_hcd *hcd, u8 pin_number, u8 value)
1654 {
1655 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1656 	u8 mask, idx;
1657 
1658 	--pin_number;
1659 	if (pin_number >= MAX3421_GPOUT_COUNT)
1660 		return;
1661 
1662 	mask = 1u << (pin_number % 4);
1663 	idx = pin_number / 4;
1664 
1665 	if (value)
1666 		max3421_hcd->iopins[idx] |=  mask;
1667 	else
1668 		max3421_hcd->iopins[idx] &= ~mask;
1669 	set_bit(IOPIN_UPDATE, &max3421_hcd->todo);
1670 	wake_up_process(max3421_hcd->spi_thread);
1671 }
1672 
1673 static int
1674 max3421_hub_control(struct usb_hcd *hcd, u16 type_req, u16 value, u16 index,
1675 		    char *buf, u16 length)
1676 {
1677 	struct spi_device *spi = to_spi_device(hcd->self.controller);
1678 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1679 	struct max3421_hcd_platform_data *pdata;
1680 	unsigned long flags;
1681 	int retval = 0;
1682 
1683 	pdata = spi->dev.platform_data;
1684 
1685 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1686 
1687 	switch (type_req) {
1688 	case ClearHubFeature:
1689 		break;
1690 	case ClearPortFeature:
1691 		switch (value) {
1692 		case USB_PORT_FEAT_SUSPEND:
1693 			break;
1694 		case USB_PORT_FEAT_POWER:
1695 			dev_dbg(hcd->self.controller, "power-off\n");
1696 			max3421_gpout_set_value(hcd, pdata->vbus_gpout,
1697 						!pdata->vbus_active_level);
1698 			fallthrough;
1699 		default:
1700 			max3421_hcd->port_status &= ~(1 << value);
1701 		}
1702 		break;
1703 	case GetHubDescriptor:
1704 		hub_descriptor((struct usb_hub_descriptor *) buf);
1705 		break;
1706 
1707 	case DeviceRequest | USB_REQ_GET_DESCRIPTOR:
1708 	case GetPortErrorCount:
1709 	case SetHubDepth:
1710 		/* USB3 only */
1711 		goto error;
1712 
1713 	case GetHubStatus:
1714 		*(__le32 *) buf = cpu_to_le32(0);
1715 		break;
1716 
1717 	case GetPortStatus:
1718 		if (index != 1) {
1719 			retval = -EPIPE;
1720 			goto error;
1721 		}
1722 		((__le16 *) buf)[0] = cpu_to_le16(max3421_hcd->port_status);
1723 		((__le16 *) buf)[1] =
1724 			cpu_to_le16(max3421_hcd->port_status >> 16);
1725 		break;
1726 
1727 	case SetHubFeature:
1728 		retval = -EPIPE;
1729 		break;
1730 
1731 	case SetPortFeature:
1732 		switch (value) {
1733 		case USB_PORT_FEAT_LINK_STATE:
1734 		case USB_PORT_FEAT_U1_TIMEOUT:
1735 		case USB_PORT_FEAT_U2_TIMEOUT:
1736 		case USB_PORT_FEAT_BH_PORT_RESET:
1737 			goto error;
1738 		case USB_PORT_FEAT_SUSPEND:
1739 			if (max3421_hcd->active)
1740 				max3421_hcd->port_status |=
1741 					USB_PORT_STAT_SUSPEND;
1742 			break;
1743 		case USB_PORT_FEAT_POWER:
1744 			dev_dbg(hcd->self.controller, "power-on\n");
1745 			max3421_hcd->port_status |= USB_PORT_STAT_POWER;
1746 			max3421_gpout_set_value(hcd, pdata->vbus_gpout,
1747 						pdata->vbus_active_level);
1748 			break;
1749 		case USB_PORT_FEAT_RESET:
1750 			max3421_reset_port(hcd);
1751 			fallthrough;
1752 		default:
1753 			if ((max3421_hcd->port_status & USB_PORT_STAT_POWER)
1754 			    != 0)
1755 				max3421_hcd->port_status |= (1 << value);
1756 		}
1757 		break;
1758 
1759 	default:
1760 		dev_dbg(hcd->self.controller,
1761 			"hub control req%04x v%04x i%04x l%d\n",
1762 			type_req, value, index, length);
1763 error:		/* "protocol stall" on error */
1764 		retval = -EPIPE;
1765 	}
1766 
1767 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1768 	return retval;
1769 }
1770 
1771 static int
1772 max3421_bus_suspend(struct usb_hcd *hcd)
1773 {
1774 	return -1;
1775 }
1776 
1777 static int
1778 max3421_bus_resume(struct usb_hcd *hcd)
1779 {
1780 	return -1;
1781 }
1782 
1783 static const struct hc_driver max3421_hcd_desc = {
1784 	.description =		"max3421",
1785 	.product_desc =		DRIVER_DESC,
1786 	.hcd_priv_size =	sizeof(struct max3421_hcd),
1787 	.flags =		HCD_USB11,
1788 	.reset =		max3421_reset,
1789 	.start =		max3421_start,
1790 	.stop =			max3421_stop,
1791 	.get_frame_number =	max3421_get_frame_number,
1792 	.urb_enqueue =		max3421_urb_enqueue,
1793 	.urb_dequeue =		max3421_urb_dequeue,
1794 	.endpoint_disable =	max3421_endpoint_disable,
1795 	.hub_status_data =	max3421_hub_status_data,
1796 	.hub_control =		max3421_hub_control,
1797 	.bus_suspend =		max3421_bus_suspend,
1798 	.bus_resume =		max3421_bus_resume,
1799 };
1800 
1801 static int
1802 max3421_of_vbus_en_pin(struct device *dev, struct max3421_hcd_platform_data *pdata)
1803 {
1804 	int retval;
1805 	uint32_t value[2];
1806 
1807 	if (!pdata)
1808 		return -EINVAL;
1809 
1810 	retval = of_property_read_u32_array(dev->of_node, "maxim,vbus-en-pin", value, 2);
1811 	if (retval) {
1812 		dev_err(dev, "device tree node property 'maxim,vbus-en-pin' is missing\n");
1813 		return retval;
1814 	}
1815 	dev_info(dev, "property 'maxim,vbus-en-pin' value is <%d %d>\n", value[0], value[1]);
1816 
1817 	pdata->vbus_gpout = value[0];
1818 	pdata->vbus_active_level = value[1];
1819 
1820 	return 0;
1821 }
1822 
1823 static int
1824 max3421_probe(struct spi_device *spi)
1825 {
1826 	struct device *dev = &spi->dev;
1827 	struct max3421_hcd *max3421_hcd;
1828 	struct usb_hcd *hcd = NULL;
1829 	struct max3421_hcd_platform_data *pdata = NULL;
1830 	int retval;
1831 
1832 	if (spi_setup(spi) < 0) {
1833 		dev_err(&spi->dev, "Unable to setup SPI bus");
1834 		return -EFAULT;
1835 	}
1836 
1837 	if (!spi->irq) {
1838 		dev_err(dev, "Failed to get SPI IRQ");
1839 		return -EFAULT;
1840 	}
1841 
1842 	if (IS_ENABLED(CONFIG_OF) && dev->of_node) {
1843 		pdata = devm_kzalloc(&spi->dev, sizeof(*pdata), GFP_KERNEL);
1844 		if (!pdata) {
1845 			retval = -ENOMEM;
1846 			goto error;
1847 		}
1848 		retval = max3421_of_vbus_en_pin(dev, pdata);
1849 		if (retval)
1850 			goto error;
1851 
1852 		spi->dev.platform_data = pdata;
1853 	}
1854 
1855 	pdata = spi->dev.platform_data;
1856 	if (!pdata) {
1857 		dev_err(&spi->dev, "driver configuration data is not provided\n");
1858 		retval = -EFAULT;
1859 		goto error;
1860 	}
1861 	if (pdata->vbus_active_level > 1) {
1862 		dev_err(&spi->dev, "vbus active level value %d is out of range (0/1)\n", pdata->vbus_active_level);
1863 		retval = -EINVAL;
1864 		goto error;
1865 	}
1866 	if (pdata->vbus_gpout < 1 || pdata->vbus_gpout > MAX3421_GPOUT_COUNT) {
1867 		dev_err(&spi->dev, "vbus gpout value %d is out of range (1..8)\n", pdata->vbus_gpout);
1868 		retval = -EINVAL;
1869 		goto error;
1870 	}
1871 
1872 	retval = -ENOMEM;
1873 	hcd = usb_create_hcd(&max3421_hcd_desc, &spi->dev,
1874 			     dev_name(&spi->dev));
1875 	if (!hcd) {
1876 		dev_err(&spi->dev, "failed to create HCD structure\n");
1877 		goto error;
1878 	}
1879 	set_bit(HCD_FLAG_POLL_RH, &hcd->flags);
1880 	max3421_hcd = hcd_to_max3421(hcd);
1881 	INIT_LIST_HEAD(&max3421_hcd->ep_list);
1882 	spi_set_drvdata(spi, max3421_hcd);
1883 
1884 	max3421_hcd->tx = kmalloc(sizeof(*max3421_hcd->tx), GFP_KERNEL);
1885 	if (!max3421_hcd->tx)
1886 		goto error;
1887 	max3421_hcd->rx = kmalloc(sizeof(*max3421_hcd->rx), GFP_KERNEL);
1888 	if (!max3421_hcd->rx)
1889 		goto error;
1890 
1891 	max3421_hcd->spi_thread = kthread_run(max3421_spi_thread, hcd,
1892 					      "max3421_spi_thread");
1893 	if (max3421_hcd->spi_thread == ERR_PTR(-ENOMEM)) {
1894 		dev_err(&spi->dev,
1895 			"failed to create SPI thread (out of memory)\n");
1896 		goto error;
1897 	}
1898 
1899 	retval = usb_add_hcd(hcd, 0, 0);
1900 	if (retval) {
1901 		dev_err(&spi->dev, "failed to add HCD\n");
1902 		goto error;
1903 	}
1904 
1905 	retval = request_irq(spi->irq, max3421_irq_handler,
1906 			     IRQF_TRIGGER_LOW, "max3421", hcd);
1907 	if (retval < 0) {
1908 		dev_err(&spi->dev, "failed to request irq %d\n", spi->irq);
1909 		goto error;
1910 	}
1911 	return 0;
1912 
1913 error:
1914 	if (IS_ENABLED(CONFIG_OF) && dev->of_node && pdata) {
1915 		devm_kfree(&spi->dev, pdata);
1916 		spi->dev.platform_data = NULL;
1917 	}
1918 
1919 	if (hcd) {
1920 		kfree(max3421_hcd->tx);
1921 		kfree(max3421_hcd->rx);
1922 		if (max3421_hcd->spi_thread)
1923 			kthread_stop(max3421_hcd->spi_thread);
1924 		usb_put_hcd(hcd);
1925 	}
1926 	return retval;
1927 }
1928 
1929 static void
1930 max3421_remove(struct spi_device *spi)
1931 {
1932 	struct max3421_hcd *max3421_hcd;
1933 	struct usb_hcd *hcd;
1934 	unsigned long flags;
1935 
1936 	max3421_hcd = spi_get_drvdata(spi);
1937 	hcd = max3421_to_hcd(max3421_hcd);
1938 
1939 	usb_remove_hcd(hcd);
1940 
1941 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1942 
1943 	kthread_stop(max3421_hcd->spi_thread);
1944 
1945 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1946 
1947 	free_irq(spi->irq, hcd);
1948 
1949 	usb_put_hcd(hcd);
1950 }
1951 
1952 static const struct of_device_id max3421_of_match_table[] = {
1953 	{ .compatible = "maxim,max3421", },
1954 	{},
1955 };
1956 MODULE_DEVICE_TABLE(of, max3421_of_match_table);
1957 
1958 static struct spi_driver max3421_driver = {
1959 	.probe		= max3421_probe,
1960 	.remove		= max3421_remove,
1961 	.driver		= {
1962 		.name	= "max3421-hcd",
1963 		.of_match_table = of_match_ptr(max3421_of_match_table),
1964 	},
1965 };
1966 
1967 module_spi_driver(max3421_driver);
1968 
1969 MODULE_DESCRIPTION(DRIVER_DESC);
1970 MODULE_AUTHOR("David Mosberger <davidm@egauge.net>");
1971 MODULE_LICENSE("GPL");
1972