xref: /openbmc/linux/drivers/usb/host/max3421-hcd.c (revision 76a4f7cc)
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 	struct max3421_hcd *next;
129 
130 	enum max3421_rh_state rh_state;
131 	/* lower 16 bits contain port status, upper 16 bits the change mask: */
132 	u32 port_status;
133 
134 	unsigned active:1;
135 
136 	struct list_head ep_list;	/* list of EP's with work */
137 
138 	/*
139 	 * The following are owned by spi_thread (may be accessed by
140 	 * SPI-thread without acquiring the HCD lock:
141 	 */
142 	u8 rev;				/* chip revision */
143 	u16 frame_number;
144 	/*
145 	 * kmalloc'd buffers guaranteed to be in separate (DMA)
146 	 * cache-lines:
147 	 */
148 	struct max3421_dma_buf *tx;
149 	struct max3421_dma_buf *rx;
150 	/*
151 	 * URB we're currently processing.  Must not be reset to NULL
152 	 * unless MAX3421E chip is idle:
153 	 */
154 	struct urb *curr_urb;
155 	enum scheduling_pass sched_pass;
156 	int urb_done;			/* > 0 -> no errors, < 0: errno */
157 	size_t curr_len;
158 	u8 hien;
159 	u8 mode;
160 	u8 iopins[2];
161 	unsigned long todo;
162 #ifdef DEBUG
163 	unsigned long err_stat[16];
164 #endif
165 };
166 
167 struct max3421_ep {
168 	struct usb_host_endpoint *ep;
169 	struct list_head ep_list;
170 	u32 naks;
171 	u16 last_active;		/* frame # this ep was last active */
172 	enum pkt_state pkt_state;
173 	u8 retries;
174 	u8 retransmit;			/* packet needs retransmission */
175 };
176 
177 static struct max3421_hcd *max3421_hcd_list;
178 
179 #define MAX3421_FIFO_SIZE	64
180 
181 #define MAX3421_SPI_DIR_RD	0	/* read register from MAX3421 */
182 #define MAX3421_SPI_DIR_WR	1	/* write register to MAX3421 */
183 
184 /* SPI commands: */
185 #define MAX3421_SPI_DIR_SHIFT	1
186 #define MAX3421_SPI_REG_SHIFT	3
187 
188 #define MAX3421_REG_RCVFIFO	1
189 #define MAX3421_REG_SNDFIFO	2
190 #define MAX3421_REG_SUDFIFO	4
191 #define MAX3421_REG_RCVBC	6
192 #define MAX3421_REG_SNDBC	7
193 #define MAX3421_REG_USBIRQ	13
194 #define MAX3421_REG_USBIEN	14
195 #define MAX3421_REG_USBCTL	15
196 #define MAX3421_REG_CPUCTL	16
197 #define MAX3421_REG_PINCTL	17
198 #define MAX3421_REG_REVISION	18
199 #define MAX3421_REG_IOPINS1	20
200 #define MAX3421_REG_IOPINS2	21
201 #define MAX3421_REG_GPINIRQ	22
202 #define MAX3421_REG_GPINIEN	23
203 #define MAX3421_REG_GPINPOL	24
204 #define MAX3421_REG_HIRQ	25
205 #define MAX3421_REG_HIEN	26
206 #define MAX3421_REG_MODE	27
207 #define MAX3421_REG_PERADDR	28
208 #define MAX3421_REG_HCTL	29
209 #define MAX3421_REG_HXFR	30
210 #define MAX3421_REG_HRSL	31
211 
212 enum {
213 	MAX3421_USBIRQ_OSCOKIRQ_BIT = 0,
214 	MAX3421_USBIRQ_NOVBUSIRQ_BIT = 5,
215 	MAX3421_USBIRQ_VBUSIRQ_BIT
216 };
217 
218 enum {
219 	MAX3421_CPUCTL_IE_BIT = 0,
220 	MAX3421_CPUCTL_PULSEWID0_BIT = 6,
221 	MAX3421_CPUCTL_PULSEWID1_BIT
222 };
223 
224 enum {
225 	MAX3421_USBCTL_PWRDOWN_BIT = 4,
226 	MAX3421_USBCTL_CHIPRES_BIT
227 };
228 
229 enum {
230 	MAX3421_PINCTL_GPXA_BIT	= 0,
231 	MAX3421_PINCTL_GPXB_BIT,
232 	MAX3421_PINCTL_POSINT_BIT,
233 	MAX3421_PINCTL_INTLEVEL_BIT,
234 	MAX3421_PINCTL_FDUPSPI_BIT,
235 	MAX3421_PINCTL_EP0INAK_BIT,
236 	MAX3421_PINCTL_EP2INAK_BIT,
237 	MAX3421_PINCTL_EP3INAK_BIT,
238 };
239 
240 enum {
241 	MAX3421_HI_BUSEVENT_BIT = 0,	/* bus-reset/-resume */
242 	MAX3421_HI_RWU_BIT,		/* remote wakeup */
243 	MAX3421_HI_RCVDAV_BIT,		/* receive FIFO data available */
244 	MAX3421_HI_SNDBAV_BIT,		/* send buffer available */
245 	MAX3421_HI_SUSDN_BIT,		/* suspend operation done */
246 	MAX3421_HI_CONDET_BIT,		/* peripheral connect/disconnect */
247 	MAX3421_HI_FRAME_BIT,		/* frame generator */
248 	MAX3421_HI_HXFRDN_BIT,		/* host transfer done */
249 };
250 
251 enum {
252 	MAX3421_HCTL_BUSRST_BIT = 0,
253 	MAX3421_HCTL_FRMRST_BIT,
254 	MAX3421_HCTL_SAMPLEBUS_BIT,
255 	MAX3421_HCTL_SIGRSM_BIT,
256 	MAX3421_HCTL_RCVTOG0_BIT,
257 	MAX3421_HCTL_RCVTOG1_BIT,
258 	MAX3421_HCTL_SNDTOG0_BIT,
259 	MAX3421_HCTL_SNDTOG1_BIT
260 };
261 
262 enum {
263 	MAX3421_MODE_HOST_BIT = 0,
264 	MAX3421_MODE_LOWSPEED_BIT,
265 	MAX3421_MODE_HUBPRE_BIT,
266 	MAX3421_MODE_SOFKAENAB_BIT,
267 	MAX3421_MODE_SEPIRQ_BIT,
268 	MAX3421_MODE_DELAYISO_BIT,
269 	MAX3421_MODE_DMPULLDN_BIT,
270 	MAX3421_MODE_DPPULLDN_BIT
271 };
272 
273 enum {
274 	MAX3421_HRSL_OK = 0,
275 	MAX3421_HRSL_BUSY,
276 	MAX3421_HRSL_BADREQ,
277 	MAX3421_HRSL_UNDEF,
278 	MAX3421_HRSL_NAK,
279 	MAX3421_HRSL_STALL,
280 	MAX3421_HRSL_TOGERR,
281 	MAX3421_HRSL_WRONGPID,
282 	MAX3421_HRSL_BADBC,
283 	MAX3421_HRSL_PIDERR,
284 	MAX3421_HRSL_PKTERR,
285 	MAX3421_HRSL_CRCERR,
286 	MAX3421_HRSL_KERR,
287 	MAX3421_HRSL_JERR,
288 	MAX3421_HRSL_TIMEOUT,
289 	MAX3421_HRSL_BABBLE,
290 	MAX3421_HRSL_RESULT_MASK = 0xf,
291 	MAX3421_HRSL_RCVTOGRD_BIT = 4,
292 	MAX3421_HRSL_SNDTOGRD_BIT,
293 	MAX3421_HRSL_KSTATUS_BIT,
294 	MAX3421_HRSL_JSTATUS_BIT
295 };
296 
297 /* Return same error-codes as ohci.h:cc_to_error: */
298 static const int hrsl_to_error[] = {
299 	[MAX3421_HRSL_OK] =		0,
300 	[MAX3421_HRSL_BUSY] =		-EINVAL,
301 	[MAX3421_HRSL_BADREQ] =		-EINVAL,
302 	[MAX3421_HRSL_UNDEF] =		-EINVAL,
303 	[MAX3421_HRSL_NAK] =		-EAGAIN,
304 	[MAX3421_HRSL_STALL] =		-EPIPE,
305 	[MAX3421_HRSL_TOGERR] =		-EILSEQ,
306 	[MAX3421_HRSL_WRONGPID] =	-EPROTO,
307 	[MAX3421_HRSL_BADBC] =		-EREMOTEIO,
308 	[MAX3421_HRSL_PIDERR] =		-EPROTO,
309 	[MAX3421_HRSL_PKTERR] =		-EPROTO,
310 	[MAX3421_HRSL_CRCERR] =		-EILSEQ,
311 	[MAX3421_HRSL_KERR] =		-EIO,
312 	[MAX3421_HRSL_JERR] =		-EIO,
313 	[MAX3421_HRSL_TIMEOUT] =	-ETIME,
314 	[MAX3421_HRSL_BABBLE] =		-EOVERFLOW
315 };
316 
317 /*
318  * See https://www.beyondlogic.org/usbnutshell/usb4.shtml#Control for a
319  * reasonable overview of how control transfers use the the IN/OUT
320  * tokens.
321  */
322 #define MAX3421_HXFR_BULK_IN(ep)	(0x00 | (ep))	/* bulk or interrupt */
323 #define MAX3421_HXFR_SETUP		 0x10
324 #define MAX3421_HXFR_BULK_OUT(ep)	(0x20 | (ep))	/* bulk or interrupt */
325 #define MAX3421_HXFR_ISO_IN(ep)		(0x40 | (ep))
326 #define MAX3421_HXFR_ISO_OUT(ep)	(0x60 | (ep))
327 #define MAX3421_HXFR_HS_IN		 0x80		/* handshake in */
328 #define MAX3421_HXFR_HS_OUT		 0xa0		/* handshake out */
329 
330 #define field(val, bit)	((val) << (bit))
331 
332 static inline s16
333 frame_diff(u16 left, u16 right)
334 {
335 	return ((unsigned) (left - right)) % (USB_MAX_FRAME_NUMBER + 1);
336 }
337 
338 static inline struct max3421_hcd *
339 hcd_to_max3421(struct usb_hcd *hcd)
340 {
341 	return (struct max3421_hcd *) hcd->hcd_priv;
342 }
343 
344 static inline struct usb_hcd *
345 max3421_to_hcd(struct max3421_hcd *max3421_hcd)
346 {
347 	return container_of((void *) max3421_hcd, struct usb_hcd, hcd_priv);
348 }
349 
350 static u8
351 spi_rd8(struct usb_hcd *hcd, unsigned int reg)
352 {
353 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
354 	struct spi_device *spi = to_spi_device(hcd->self.controller);
355 	struct spi_transfer transfer;
356 	struct spi_message msg;
357 
358 	memset(&transfer, 0, sizeof(transfer));
359 
360 	spi_message_init(&msg);
361 
362 	max3421_hcd->tx->data[0] =
363 		(field(reg, MAX3421_SPI_REG_SHIFT) |
364 		 field(MAX3421_SPI_DIR_RD, MAX3421_SPI_DIR_SHIFT));
365 
366 	transfer.tx_buf = max3421_hcd->tx->data;
367 	transfer.rx_buf = max3421_hcd->rx->data;
368 	transfer.len = 2;
369 
370 	spi_message_add_tail(&transfer, &msg);
371 	spi_sync(spi, &msg);
372 
373 	return max3421_hcd->rx->data[1];
374 }
375 
376 static void
377 spi_wr8(struct usb_hcd *hcd, unsigned int reg, u8 val)
378 {
379 	struct spi_device *spi = to_spi_device(hcd->self.controller);
380 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
381 	struct spi_transfer transfer;
382 	struct spi_message msg;
383 
384 	memset(&transfer, 0, sizeof(transfer));
385 
386 	spi_message_init(&msg);
387 
388 	max3421_hcd->tx->data[0] =
389 		(field(reg, MAX3421_SPI_REG_SHIFT) |
390 		 field(MAX3421_SPI_DIR_WR, MAX3421_SPI_DIR_SHIFT));
391 	max3421_hcd->tx->data[1] = val;
392 
393 	transfer.tx_buf = max3421_hcd->tx->data;
394 	transfer.len = 2;
395 
396 	spi_message_add_tail(&transfer, &msg);
397 	spi_sync(spi, &msg);
398 }
399 
400 static void
401 spi_rd_buf(struct usb_hcd *hcd, unsigned int reg, void *buf, size_t len)
402 {
403 	struct spi_device *spi = to_spi_device(hcd->self.controller);
404 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
405 	struct spi_transfer transfer[2];
406 	struct spi_message msg;
407 
408 	memset(transfer, 0, sizeof(transfer));
409 
410 	spi_message_init(&msg);
411 
412 	max3421_hcd->tx->data[0] =
413 		(field(reg, MAX3421_SPI_REG_SHIFT) |
414 		 field(MAX3421_SPI_DIR_RD, MAX3421_SPI_DIR_SHIFT));
415 	transfer[0].tx_buf = max3421_hcd->tx->data;
416 	transfer[0].len = 1;
417 
418 	transfer[1].rx_buf = buf;
419 	transfer[1].len = len;
420 
421 	spi_message_add_tail(&transfer[0], &msg);
422 	spi_message_add_tail(&transfer[1], &msg);
423 	spi_sync(spi, &msg);
424 }
425 
426 static void
427 spi_wr_buf(struct usb_hcd *hcd, unsigned int reg, void *buf, size_t len)
428 {
429 	struct spi_device *spi = to_spi_device(hcd->self.controller);
430 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
431 	struct spi_transfer transfer[2];
432 	struct spi_message msg;
433 
434 	memset(transfer, 0, sizeof(transfer));
435 
436 	spi_message_init(&msg);
437 
438 	max3421_hcd->tx->data[0] =
439 		(field(reg, MAX3421_SPI_REG_SHIFT) |
440 		 field(MAX3421_SPI_DIR_WR, MAX3421_SPI_DIR_SHIFT));
441 
442 	transfer[0].tx_buf = max3421_hcd->tx->data;
443 	transfer[0].len = 1;
444 
445 	transfer[1].tx_buf = buf;
446 	transfer[1].len = len;
447 
448 	spi_message_add_tail(&transfer[0], &msg);
449 	spi_message_add_tail(&transfer[1], &msg);
450 	spi_sync(spi, &msg);
451 }
452 
453 /*
454  * Figure out the correct setting for the LOWSPEED and HUBPRE mode
455  * bits.  The HUBPRE bit needs to be set when MAX3421E operates at
456  * full speed, but it's talking to a low-speed device (i.e., through a
457  * hub).  Setting that bit ensures that every low-speed packet is
458  * preceded by a full-speed PRE PID.  Possible configurations:
459  *
460  * Hub speed:	Device speed:	=>	LOWSPEED bit:	HUBPRE bit:
461  *	FULL	FULL		=>	0		0
462  *	FULL	LOW		=>	1		1
463  *	LOW	LOW		=>	1		0
464  *	LOW	FULL		=>	1		0
465  */
466 static void
467 max3421_set_speed(struct usb_hcd *hcd, struct usb_device *dev)
468 {
469 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
470 	u8 mode_lowspeed, mode_hubpre, mode = max3421_hcd->mode;
471 
472 	mode_lowspeed = BIT(MAX3421_MODE_LOWSPEED_BIT);
473 	mode_hubpre   = BIT(MAX3421_MODE_HUBPRE_BIT);
474 	if (max3421_hcd->port_status & USB_PORT_STAT_LOW_SPEED) {
475 		mode |=  mode_lowspeed;
476 		mode &= ~mode_hubpre;
477 	} else if (dev->speed == USB_SPEED_LOW) {
478 		mode |= mode_lowspeed | mode_hubpre;
479 	} else {
480 		mode &= ~(mode_lowspeed | mode_hubpre);
481 	}
482 	if (mode != max3421_hcd->mode) {
483 		max3421_hcd->mode = mode;
484 		spi_wr8(hcd, MAX3421_REG_MODE, max3421_hcd->mode);
485 	}
486 
487 }
488 
489 /*
490  * Caller must NOT hold HCD spinlock.
491  */
492 static void
493 max3421_set_address(struct usb_hcd *hcd, struct usb_device *dev, int epnum)
494 {
495 	int rcvtog, sndtog;
496 	u8 hctl;
497 
498 	/* setup new endpoint's toggle bits: */
499 	rcvtog = usb_gettoggle(dev, epnum, 0);
500 	sndtog = usb_gettoggle(dev, epnum, 1);
501 	hctl = (BIT(rcvtog + MAX3421_HCTL_RCVTOG0_BIT) |
502 		BIT(sndtog + MAX3421_HCTL_SNDTOG0_BIT));
503 
504 	spi_wr8(hcd, MAX3421_REG_HCTL, hctl);
505 
506 	/*
507 	 * Note: devnum for one and the same device can change during
508 	 * address-assignment so it's best to just always load the
509 	 * address whenever the end-point changed/was forced.
510 	 */
511 	spi_wr8(hcd, MAX3421_REG_PERADDR, dev->devnum);
512 }
513 
514 static int
515 max3421_ctrl_setup(struct usb_hcd *hcd, struct urb *urb)
516 {
517 	spi_wr_buf(hcd, MAX3421_REG_SUDFIFO, urb->setup_packet, 8);
518 	return MAX3421_HXFR_SETUP;
519 }
520 
521 static int
522 max3421_transfer_in(struct usb_hcd *hcd, struct urb *urb)
523 {
524 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
525 	int epnum = usb_pipeendpoint(urb->pipe);
526 
527 	max3421_hcd->curr_len = 0;
528 	max3421_hcd->hien |= BIT(MAX3421_HI_RCVDAV_BIT);
529 	return MAX3421_HXFR_BULK_IN(epnum);
530 }
531 
532 static int
533 max3421_transfer_out(struct usb_hcd *hcd, struct urb *urb, int fast_retransmit)
534 {
535 	struct spi_device *spi = to_spi_device(hcd->self.controller);
536 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
537 	int epnum = usb_pipeendpoint(urb->pipe);
538 	u32 max_packet;
539 	void *src;
540 
541 	src = urb->transfer_buffer + urb->actual_length;
542 
543 	if (fast_retransmit) {
544 		if (max3421_hcd->rev == 0x12) {
545 			/* work around rev 0x12 bug: */
546 			spi_wr8(hcd, MAX3421_REG_SNDBC, 0);
547 			spi_wr8(hcd, MAX3421_REG_SNDFIFO, ((u8 *) src)[0]);
548 			spi_wr8(hcd, MAX3421_REG_SNDBC, max3421_hcd->curr_len);
549 		}
550 		return MAX3421_HXFR_BULK_OUT(epnum);
551 	}
552 
553 	max_packet = usb_maxpacket(urb->dev, urb->pipe, 1);
554 
555 	if (max_packet > MAX3421_FIFO_SIZE) {
556 		/*
557 		 * We do not support isochronous transfers at this
558 		 * time.
559 		 */
560 		dev_err(&spi->dev,
561 			"%s: packet-size of %u too big (limit is %u bytes)",
562 			__func__, max_packet, MAX3421_FIFO_SIZE);
563 		max3421_hcd->urb_done = -EMSGSIZE;
564 		return -EMSGSIZE;
565 	}
566 	max3421_hcd->curr_len = min((urb->transfer_buffer_length -
567 				     urb->actual_length), max_packet);
568 
569 	spi_wr_buf(hcd, MAX3421_REG_SNDFIFO, src, max3421_hcd->curr_len);
570 	spi_wr8(hcd, MAX3421_REG_SNDBC, max3421_hcd->curr_len);
571 	return MAX3421_HXFR_BULK_OUT(epnum);
572 }
573 
574 /*
575  * Issue the next host-transfer command.
576  * Caller must NOT hold HCD spinlock.
577  */
578 static void
579 max3421_next_transfer(struct usb_hcd *hcd, int fast_retransmit)
580 {
581 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
582 	struct urb *urb = max3421_hcd->curr_urb;
583 	struct max3421_ep *max3421_ep;
584 	int cmd = -EINVAL;
585 
586 	if (!urb)
587 		return;	/* nothing to do */
588 
589 	max3421_ep = urb->ep->hcpriv;
590 
591 	switch (max3421_ep->pkt_state) {
592 	case PKT_STATE_SETUP:
593 		cmd = max3421_ctrl_setup(hcd, urb);
594 		break;
595 
596 	case PKT_STATE_TRANSFER:
597 		if (usb_urb_dir_in(urb))
598 			cmd = max3421_transfer_in(hcd, urb);
599 		else
600 			cmd = max3421_transfer_out(hcd, urb, fast_retransmit);
601 		break;
602 
603 	case PKT_STATE_TERMINATE:
604 		/*
605 		 * IN transfers are terminated with HS_OUT token,
606 		 * OUT transfers with HS_IN:
607 		 */
608 		if (usb_urb_dir_in(urb))
609 			cmd = MAX3421_HXFR_HS_OUT;
610 		else
611 			cmd = MAX3421_HXFR_HS_IN;
612 		break;
613 	}
614 
615 	if (cmd < 0)
616 		return;
617 
618 	/* issue the command and wait for host-xfer-done interrupt: */
619 
620 	spi_wr8(hcd, MAX3421_REG_HXFR, cmd);
621 	max3421_hcd->hien |= BIT(MAX3421_HI_HXFRDN_BIT);
622 }
623 
624 /*
625  * Find the next URB to process and start its execution.
626  *
627  * At this time, we do not anticipate ever connecting a USB hub to the
628  * MAX3421 chip, so at most USB device can be connected and we can use
629  * a simplistic scheduler: at the start of a frame, schedule all
630  * periodic transfers.  Once that is done, use the remainder of the
631  * frame to process non-periodic (bulk & control) transfers.
632  *
633  * Preconditions:
634  * o Caller must NOT hold HCD spinlock.
635  * o max3421_hcd->curr_urb MUST BE NULL.
636  * o MAX3421E chip must be idle.
637  */
638 static int
639 max3421_select_and_start_urb(struct usb_hcd *hcd)
640 {
641 	struct spi_device *spi = to_spi_device(hcd->self.controller);
642 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
643 	struct urb *urb, *curr_urb = NULL;
644 	struct max3421_ep *max3421_ep;
645 	int epnum;
646 	struct usb_host_endpoint *ep;
647 	struct list_head *pos;
648 	unsigned long flags;
649 
650 	spin_lock_irqsave(&max3421_hcd->lock, flags);
651 
652 	for (;
653 	     max3421_hcd->sched_pass < SCHED_PASS_DONE;
654 	     ++max3421_hcd->sched_pass)
655 		list_for_each(pos, &max3421_hcd->ep_list) {
656 			urb = NULL;
657 			max3421_ep = container_of(pos, struct max3421_ep,
658 						  ep_list);
659 			ep = max3421_ep->ep;
660 
661 			switch (usb_endpoint_type(&ep->desc)) {
662 			case USB_ENDPOINT_XFER_ISOC:
663 			case USB_ENDPOINT_XFER_INT:
664 				if (max3421_hcd->sched_pass !=
665 				    SCHED_PASS_PERIODIC)
666 					continue;
667 				break;
668 
669 			case USB_ENDPOINT_XFER_CONTROL:
670 			case USB_ENDPOINT_XFER_BULK:
671 				if (max3421_hcd->sched_pass !=
672 				    SCHED_PASS_NON_PERIODIC)
673 					continue;
674 				break;
675 			}
676 
677 			if (list_empty(&ep->urb_list))
678 				continue;	/* nothing to do */
679 			urb = list_first_entry(&ep->urb_list, struct urb,
680 					       urb_list);
681 			if (urb->unlinked) {
682 				dev_dbg(&spi->dev, "%s: URB %p unlinked=%d",
683 					__func__, urb, urb->unlinked);
684 				max3421_hcd->curr_urb = urb;
685 				max3421_hcd->urb_done = 1;
686 				spin_unlock_irqrestore(&max3421_hcd->lock,
687 						       flags);
688 				return 1;
689 			}
690 
691 			switch (usb_endpoint_type(&ep->desc)) {
692 			case USB_ENDPOINT_XFER_CONTROL:
693 				/*
694 				 * Allow one control transaction per
695 				 * frame per endpoint:
696 				 */
697 				if (frame_diff(max3421_ep->last_active,
698 					       max3421_hcd->frame_number) == 0)
699 					continue;
700 				break;
701 
702 			case USB_ENDPOINT_XFER_BULK:
703 				if (max3421_ep->retransmit
704 				    && (frame_diff(max3421_ep->last_active,
705 						   max3421_hcd->frame_number)
706 					== 0))
707 					/*
708 					 * We already tried this EP
709 					 * during this frame and got a
710 					 * NAK or error; wait for next frame
711 					 */
712 					continue;
713 				break;
714 
715 			case USB_ENDPOINT_XFER_ISOC:
716 			case USB_ENDPOINT_XFER_INT:
717 				if (frame_diff(max3421_hcd->frame_number,
718 					       max3421_ep->last_active)
719 				    < urb->interval)
720 					/*
721 					 * We already processed this
722 					 * end-point in the current
723 					 * frame
724 					 */
725 					continue;
726 				break;
727 			}
728 
729 			/* move current ep to tail: */
730 			list_move_tail(pos, &max3421_hcd->ep_list);
731 			curr_urb = urb;
732 			goto done;
733 		}
734 done:
735 	if (!curr_urb) {
736 		spin_unlock_irqrestore(&max3421_hcd->lock, flags);
737 		return 0;
738 	}
739 
740 	urb = max3421_hcd->curr_urb = curr_urb;
741 	epnum = usb_endpoint_num(&urb->ep->desc);
742 	if (max3421_ep->retransmit)
743 		/* restart (part of) a USB transaction: */
744 		max3421_ep->retransmit = 0;
745 	else {
746 		/* start USB transaction: */
747 		if (usb_endpoint_xfer_control(&ep->desc)) {
748 			/*
749 			 * See USB 2.0 spec section 8.6.1
750 			 * Initialization via SETUP Token:
751 			 */
752 			usb_settoggle(urb->dev, epnum, 0, 1);
753 			usb_settoggle(urb->dev, epnum, 1, 1);
754 			max3421_ep->pkt_state = PKT_STATE_SETUP;
755 		} else
756 			max3421_ep->pkt_state = PKT_STATE_TRANSFER;
757 	}
758 
759 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
760 
761 	max3421_ep->last_active = max3421_hcd->frame_number;
762 	max3421_set_address(hcd, urb->dev, epnum);
763 	max3421_set_speed(hcd, urb->dev);
764 	max3421_next_transfer(hcd, 0);
765 	return 1;
766 }
767 
768 /*
769  * Check all endpoints for URBs that got unlinked.
770  *
771  * Caller must NOT hold HCD spinlock.
772  */
773 static int
774 max3421_check_unlink(struct usb_hcd *hcd)
775 {
776 	struct spi_device *spi = to_spi_device(hcd->self.controller);
777 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
778 	struct max3421_ep *max3421_ep;
779 	struct usb_host_endpoint *ep;
780 	struct urb *urb, *next;
781 	unsigned long flags;
782 	int retval = 0;
783 
784 	spin_lock_irqsave(&max3421_hcd->lock, flags);
785 	list_for_each_entry(max3421_ep, &max3421_hcd->ep_list, ep_list) {
786 		ep = max3421_ep->ep;
787 		list_for_each_entry_safe(urb, next, &ep->urb_list, urb_list) {
788 			if (urb->unlinked) {
789 				retval = 1;
790 				dev_dbg(&spi->dev, "%s: URB %p unlinked=%d",
791 					__func__, urb, urb->unlinked);
792 				usb_hcd_unlink_urb_from_ep(hcd, urb);
793 				spin_unlock_irqrestore(&max3421_hcd->lock,
794 						       flags);
795 				usb_hcd_giveback_urb(hcd, urb, 0);
796 				spin_lock_irqsave(&max3421_hcd->lock, flags);
797 			}
798 		}
799 	}
800 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
801 	return retval;
802 }
803 
804 /*
805  * Caller must NOT hold HCD spinlock.
806  */
807 static void
808 max3421_slow_retransmit(struct usb_hcd *hcd)
809 {
810 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
811 	struct urb *urb = max3421_hcd->curr_urb;
812 	struct max3421_ep *max3421_ep;
813 
814 	max3421_ep = urb->ep->hcpriv;
815 	max3421_ep->retransmit = 1;
816 	max3421_hcd->curr_urb = NULL;
817 }
818 
819 /*
820  * Caller must NOT hold HCD spinlock.
821  */
822 static void
823 max3421_recv_data_available(struct usb_hcd *hcd)
824 {
825 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
826 	struct urb *urb = max3421_hcd->curr_urb;
827 	size_t remaining, transfer_size;
828 	u8 rcvbc;
829 
830 	rcvbc = spi_rd8(hcd, MAX3421_REG_RCVBC);
831 
832 	if (rcvbc > MAX3421_FIFO_SIZE)
833 		rcvbc = MAX3421_FIFO_SIZE;
834 	if (urb->actual_length >= urb->transfer_buffer_length)
835 		remaining = 0;
836 	else
837 		remaining = urb->transfer_buffer_length - urb->actual_length;
838 	transfer_size = rcvbc;
839 	if (transfer_size > remaining)
840 		transfer_size = remaining;
841 	if (transfer_size > 0) {
842 		void *dst = urb->transfer_buffer + urb->actual_length;
843 
844 		spi_rd_buf(hcd, MAX3421_REG_RCVFIFO, dst, transfer_size);
845 		urb->actual_length += transfer_size;
846 		max3421_hcd->curr_len = transfer_size;
847 	}
848 
849 	/* ack the RCVDAV irq now that the FIFO has been read: */
850 	spi_wr8(hcd, MAX3421_REG_HIRQ, BIT(MAX3421_HI_RCVDAV_BIT));
851 }
852 
853 static void
854 max3421_handle_error(struct usb_hcd *hcd, u8 hrsl)
855 {
856 	struct spi_device *spi = to_spi_device(hcd->self.controller);
857 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
858 	u8 result_code = hrsl & MAX3421_HRSL_RESULT_MASK;
859 	struct urb *urb = max3421_hcd->curr_urb;
860 	struct max3421_ep *max3421_ep = urb->ep->hcpriv;
861 	int switch_sndfifo;
862 
863 	/*
864 	 * If an OUT command results in any response other than OK
865 	 * (i.e., error or NAK), we have to perform a dummy-write to
866 	 * SNDBC so the FIFO gets switched back to us.  Otherwise, we
867 	 * get out of sync with the SNDFIFO double buffer.
868 	 */
869 	switch_sndfifo = (max3421_ep->pkt_state == PKT_STATE_TRANSFER &&
870 			  usb_urb_dir_out(urb));
871 
872 	switch (result_code) {
873 	case MAX3421_HRSL_OK:
874 		return;			/* this shouldn't happen */
875 
876 	case MAX3421_HRSL_WRONGPID:	/* received wrong PID */
877 	case MAX3421_HRSL_BUSY:		/* SIE busy */
878 	case MAX3421_HRSL_BADREQ:	/* bad val in HXFR */
879 	case MAX3421_HRSL_UNDEF:	/* reserved */
880 	case MAX3421_HRSL_KERR:		/* K-state instead of response */
881 	case MAX3421_HRSL_JERR:		/* J-state instead of response */
882 		/*
883 		 * packet experienced an error that we cannot recover
884 		 * from; report error
885 		 */
886 		max3421_hcd->urb_done = hrsl_to_error[result_code];
887 		dev_dbg(&spi->dev, "%s: unexpected error HRSL=0x%02x",
888 			__func__, hrsl);
889 		break;
890 
891 	case MAX3421_HRSL_TOGERR:
892 		if (usb_urb_dir_in(urb))
893 			; /* don't do anything (device will switch toggle) */
894 		else {
895 			/* flip the send toggle bit: */
896 			int sndtog = (hrsl >> MAX3421_HRSL_SNDTOGRD_BIT) & 1;
897 
898 			sndtog ^= 1;
899 			spi_wr8(hcd, MAX3421_REG_HCTL,
900 				BIT(sndtog + MAX3421_HCTL_SNDTOG0_BIT));
901 		}
902 		fallthrough;
903 	case MAX3421_HRSL_BADBC:	/* bad byte count */
904 	case MAX3421_HRSL_PIDERR:	/* received PID is corrupted */
905 	case MAX3421_HRSL_PKTERR:	/* packet error (stuff, EOP) */
906 	case MAX3421_HRSL_CRCERR:	/* CRC error */
907 	case MAX3421_HRSL_BABBLE:	/* device talked too long */
908 	case MAX3421_HRSL_TIMEOUT:
909 		if (max3421_ep->retries++ < USB_MAX_RETRIES)
910 			/* retry the packet again in the next frame */
911 			max3421_slow_retransmit(hcd);
912 		else {
913 			/* Based on ohci.h cc_to_err[]: */
914 			max3421_hcd->urb_done = hrsl_to_error[result_code];
915 			dev_dbg(&spi->dev, "%s: unexpected error HRSL=0x%02x",
916 				__func__, hrsl);
917 		}
918 		break;
919 
920 	case MAX3421_HRSL_STALL:
921 		dev_dbg(&spi->dev, "%s: unexpected error HRSL=0x%02x",
922 			__func__, hrsl);
923 		max3421_hcd->urb_done = hrsl_to_error[result_code];
924 		break;
925 
926 	case MAX3421_HRSL_NAK:
927 		/*
928 		 * Device wasn't ready for data or has no data
929 		 * available: retry the packet again.
930 		 */
931 		if (max3421_ep->naks++ < NAK_MAX_FAST_RETRANSMITS) {
932 			max3421_next_transfer(hcd, 1);
933 			switch_sndfifo = 0;
934 		} else
935 			max3421_slow_retransmit(hcd);
936 		break;
937 	}
938 	if (switch_sndfifo)
939 		spi_wr8(hcd, MAX3421_REG_SNDBC, 0);
940 }
941 
942 /*
943  * Caller must NOT hold HCD spinlock.
944  */
945 static int
946 max3421_transfer_in_done(struct usb_hcd *hcd, struct urb *urb)
947 {
948 	struct spi_device *spi = to_spi_device(hcd->self.controller);
949 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
950 	u32 max_packet;
951 
952 	if (urb->actual_length >= urb->transfer_buffer_length)
953 		return 1;	/* read is complete, so we're done */
954 
955 	/*
956 	 * USB 2.0 Section 5.3.2 Pipes: packets must be full size
957 	 * except for last one.
958 	 */
959 	max_packet = usb_maxpacket(urb->dev, urb->pipe, 0);
960 	if (max_packet > MAX3421_FIFO_SIZE) {
961 		/*
962 		 * We do not support isochronous transfers at this
963 		 * time...
964 		 */
965 		dev_err(&spi->dev,
966 			"%s: packet-size of %u too big (limit is %u bytes)",
967 			__func__, max_packet, MAX3421_FIFO_SIZE);
968 		return -EINVAL;
969 	}
970 
971 	if (max3421_hcd->curr_len < max_packet) {
972 		if (urb->transfer_flags & URB_SHORT_NOT_OK) {
973 			/*
974 			 * remaining > 0 and received an
975 			 * unexpected partial packet ->
976 			 * error
977 			 */
978 			return -EREMOTEIO;
979 		} else
980 			/* short read, but it's OK */
981 			return 1;
982 	}
983 	return 0;	/* not done */
984 }
985 
986 /*
987  * Caller must NOT hold HCD spinlock.
988  */
989 static int
990 max3421_transfer_out_done(struct usb_hcd *hcd, struct urb *urb)
991 {
992 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
993 
994 	urb->actual_length += max3421_hcd->curr_len;
995 	if (urb->actual_length < urb->transfer_buffer_length)
996 		return 0;
997 	if (urb->transfer_flags & URB_ZERO_PACKET) {
998 		/*
999 		 * Some hardware needs a zero-size packet at the end
1000 		 * of a bulk-out transfer if the last transfer was a
1001 		 * full-sized packet (i.e., such hardware use <
1002 		 * max_packet as an indicator that the end of the
1003 		 * packet has been reached).
1004 		 */
1005 		u32 max_packet = usb_maxpacket(urb->dev, urb->pipe, 1);
1006 
1007 		if (max3421_hcd->curr_len == max_packet)
1008 			return 0;
1009 	}
1010 	return 1;
1011 }
1012 
1013 /*
1014  * Caller must NOT hold HCD spinlock.
1015  */
1016 static void
1017 max3421_host_transfer_done(struct usb_hcd *hcd)
1018 {
1019 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1020 	struct urb *urb = max3421_hcd->curr_urb;
1021 	struct max3421_ep *max3421_ep;
1022 	u8 result_code, hrsl;
1023 	int urb_done = 0;
1024 
1025 	max3421_hcd->hien &= ~(BIT(MAX3421_HI_HXFRDN_BIT) |
1026 			       BIT(MAX3421_HI_RCVDAV_BIT));
1027 
1028 	hrsl = spi_rd8(hcd, MAX3421_REG_HRSL);
1029 	result_code = hrsl & MAX3421_HRSL_RESULT_MASK;
1030 
1031 #ifdef DEBUG
1032 	++max3421_hcd->err_stat[result_code];
1033 #endif
1034 
1035 	max3421_ep = urb->ep->hcpriv;
1036 
1037 	if (unlikely(result_code != MAX3421_HRSL_OK)) {
1038 		max3421_handle_error(hcd, hrsl);
1039 		return;
1040 	}
1041 
1042 	max3421_ep->naks = 0;
1043 	max3421_ep->retries = 0;
1044 	switch (max3421_ep->pkt_state) {
1045 
1046 	case PKT_STATE_SETUP:
1047 		if (urb->transfer_buffer_length > 0)
1048 			max3421_ep->pkt_state = PKT_STATE_TRANSFER;
1049 		else
1050 			max3421_ep->pkt_state = PKT_STATE_TERMINATE;
1051 		break;
1052 
1053 	case PKT_STATE_TRANSFER:
1054 		if (usb_urb_dir_in(urb))
1055 			urb_done = max3421_transfer_in_done(hcd, urb);
1056 		else
1057 			urb_done = max3421_transfer_out_done(hcd, urb);
1058 		if (urb_done > 0 && usb_pipetype(urb->pipe) == PIPE_CONTROL) {
1059 			/*
1060 			 * We aren't really done - we still need to
1061 			 * terminate the control transfer:
1062 			 */
1063 			max3421_hcd->urb_done = urb_done = 0;
1064 			max3421_ep->pkt_state = PKT_STATE_TERMINATE;
1065 		}
1066 		break;
1067 
1068 	case PKT_STATE_TERMINATE:
1069 		urb_done = 1;
1070 		break;
1071 	}
1072 
1073 	if (urb_done)
1074 		max3421_hcd->urb_done = urb_done;
1075 	else
1076 		max3421_next_transfer(hcd, 0);
1077 }
1078 
1079 /*
1080  * Caller must NOT hold HCD spinlock.
1081  */
1082 static void
1083 max3421_detect_conn(struct usb_hcd *hcd)
1084 {
1085 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1086 	unsigned int jk, have_conn = 0;
1087 	u32 old_port_status, chg;
1088 	unsigned long flags;
1089 	u8 hrsl, mode;
1090 
1091 	hrsl = spi_rd8(hcd, MAX3421_REG_HRSL);
1092 
1093 	jk = ((((hrsl >> MAX3421_HRSL_JSTATUS_BIT) & 1) << 0) |
1094 	      (((hrsl >> MAX3421_HRSL_KSTATUS_BIT) & 1) << 1));
1095 
1096 	mode = max3421_hcd->mode;
1097 
1098 	switch (jk) {
1099 	case 0x0: /* SE0: disconnect */
1100 		/*
1101 		 * Turn off SOFKAENAB bit to avoid getting interrupt
1102 		 * every milli-second:
1103 		 */
1104 		mode &= ~BIT(MAX3421_MODE_SOFKAENAB_BIT);
1105 		break;
1106 
1107 	case 0x1: /* J=0,K=1: low-speed (in full-speed or vice versa) */
1108 	case 0x2: /* J=1,K=0: full-speed (in full-speed or vice versa) */
1109 		if (jk == 0x2)
1110 			/* need to switch to the other speed: */
1111 			mode ^= BIT(MAX3421_MODE_LOWSPEED_BIT);
1112 		/* turn on SOFKAENAB bit: */
1113 		mode |= BIT(MAX3421_MODE_SOFKAENAB_BIT);
1114 		have_conn = 1;
1115 		break;
1116 
1117 	case 0x3: /* illegal */
1118 		break;
1119 	}
1120 
1121 	max3421_hcd->mode = mode;
1122 	spi_wr8(hcd, MAX3421_REG_MODE, max3421_hcd->mode);
1123 
1124 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1125 	old_port_status = max3421_hcd->port_status;
1126 	if (have_conn)
1127 		max3421_hcd->port_status |=  USB_PORT_STAT_CONNECTION;
1128 	else
1129 		max3421_hcd->port_status &= ~USB_PORT_STAT_CONNECTION;
1130 	if (mode & BIT(MAX3421_MODE_LOWSPEED_BIT))
1131 		max3421_hcd->port_status |=  USB_PORT_STAT_LOW_SPEED;
1132 	else
1133 		max3421_hcd->port_status &= ~USB_PORT_STAT_LOW_SPEED;
1134 	chg = (old_port_status ^ max3421_hcd->port_status);
1135 	max3421_hcd->port_status |= chg << 16;
1136 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1137 }
1138 
1139 static irqreturn_t
1140 max3421_irq_handler(int irq, void *dev_id)
1141 {
1142 	struct usb_hcd *hcd = dev_id;
1143 	struct spi_device *spi = to_spi_device(hcd->self.controller);
1144 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1145 
1146 	if (max3421_hcd->spi_thread)
1147 		wake_up_process(max3421_hcd->spi_thread);
1148 	if (!test_and_set_bit(ENABLE_IRQ, &max3421_hcd->todo))
1149 		disable_irq_nosync(spi->irq);
1150 	return IRQ_HANDLED;
1151 }
1152 
1153 #ifdef DEBUG
1154 
1155 static void
1156 dump_eps(struct usb_hcd *hcd)
1157 {
1158 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1159 	struct max3421_ep *max3421_ep;
1160 	struct usb_host_endpoint *ep;
1161 	char ubuf[512], *dp, *end;
1162 	unsigned long flags;
1163 	struct urb *urb;
1164 	int epnum, ret;
1165 
1166 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1167 	list_for_each_entry(max3421_ep, &max3421_hcd->ep_list, ep_list) {
1168 		ep = max3421_ep->ep;
1169 
1170 		dp = ubuf;
1171 		end = dp + sizeof(ubuf);
1172 		*dp = '\0';
1173 		list_for_each_entry(urb, &ep->urb_list, urb_list) {
1174 			ret = snprintf(dp, end - dp, " %p(%d.%s %d/%d)", urb,
1175 				       usb_pipetype(urb->pipe),
1176 				       usb_urb_dir_in(urb) ? "IN" : "OUT",
1177 				       urb->actual_length,
1178 				       urb->transfer_buffer_length);
1179 			if (ret < 0 || ret >= end - dp)
1180 				break;	/* error or buffer full */
1181 			dp += ret;
1182 		}
1183 
1184 		epnum = usb_endpoint_num(&ep->desc);
1185 		pr_info("EP%0u %u lst %04u rtr %u nak %6u rxmt %u: %s\n",
1186 			epnum, max3421_ep->pkt_state, max3421_ep->last_active,
1187 			max3421_ep->retries, max3421_ep->naks,
1188 			max3421_ep->retransmit, ubuf);
1189 	}
1190 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1191 }
1192 
1193 #endif /* DEBUG */
1194 
1195 /* Return zero if no work was performed, 1 otherwise.  */
1196 static int
1197 max3421_handle_irqs(struct usb_hcd *hcd)
1198 {
1199 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1200 	u32 chg, old_port_status;
1201 	unsigned long flags;
1202 	u8 hirq;
1203 
1204 	/*
1205 	 * Read and ack pending interrupts (CPU must never
1206 	 * clear SNDBAV directly and RCVDAV must be cleared by
1207 	 * max3421_recv_data_available()!):
1208 	 */
1209 	hirq = spi_rd8(hcd, MAX3421_REG_HIRQ);
1210 	hirq &= max3421_hcd->hien;
1211 	if (!hirq)
1212 		return 0;
1213 
1214 	spi_wr8(hcd, MAX3421_REG_HIRQ,
1215 		hirq & ~(BIT(MAX3421_HI_SNDBAV_BIT) |
1216 			 BIT(MAX3421_HI_RCVDAV_BIT)));
1217 
1218 	if (hirq & BIT(MAX3421_HI_FRAME_BIT)) {
1219 		max3421_hcd->frame_number = ((max3421_hcd->frame_number + 1)
1220 					     & USB_MAX_FRAME_NUMBER);
1221 		max3421_hcd->sched_pass = SCHED_PASS_PERIODIC;
1222 	}
1223 
1224 	if (hirq & BIT(MAX3421_HI_RCVDAV_BIT))
1225 		max3421_recv_data_available(hcd);
1226 
1227 	if (hirq & BIT(MAX3421_HI_HXFRDN_BIT))
1228 		max3421_host_transfer_done(hcd);
1229 
1230 	if (hirq & BIT(MAX3421_HI_CONDET_BIT))
1231 		max3421_detect_conn(hcd);
1232 
1233 	/*
1234 	 * Now process interrupts that may affect HCD state
1235 	 * other than the end-points:
1236 	 */
1237 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1238 
1239 	old_port_status = max3421_hcd->port_status;
1240 	if (hirq & BIT(MAX3421_HI_BUSEVENT_BIT)) {
1241 		if (max3421_hcd->port_status & USB_PORT_STAT_RESET) {
1242 			/* BUSEVENT due to completion of Bus Reset */
1243 			max3421_hcd->port_status &= ~USB_PORT_STAT_RESET;
1244 			max3421_hcd->port_status |=  USB_PORT_STAT_ENABLE;
1245 		} else {
1246 			/* BUSEVENT due to completion of Bus Resume */
1247 			pr_info("%s: BUSEVENT Bus Resume Done\n", __func__);
1248 		}
1249 	}
1250 	if (hirq & BIT(MAX3421_HI_RWU_BIT))
1251 		pr_info("%s: RWU\n", __func__);
1252 	if (hirq & BIT(MAX3421_HI_SUSDN_BIT))
1253 		pr_info("%s: SUSDN\n", __func__);
1254 
1255 	chg = (old_port_status ^ max3421_hcd->port_status);
1256 	max3421_hcd->port_status |= chg << 16;
1257 
1258 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1259 
1260 #ifdef DEBUG
1261 	{
1262 		static unsigned long last_time;
1263 		char sbuf[16 * 16], *dp, *end;
1264 		int i;
1265 
1266 		if (time_after(jiffies, last_time + 5*HZ)) {
1267 			dp = sbuf;
1268 			end = sbuf + sizeof(sbuf);
1269 			*dp = '\0';
1270 			for (i = 0; i < 16; ++i) {
1271 				int ret = snprintf(dp, end - dp, " %lu",
1272 						   max3421_hcd->err_stat[i]);
1273 				if (ret < 0 || ret >= end - dp)
1274 					break;	/* error or buffer full */
1275 				dp += ret;
1276 			}
1277 			pr_info("%s: hrsl_stats %s\n", __func__, sbuf);
1278 			memset(max3421_hcd->err_stat, 0,
1279 			       sizeof(max3421_hcd->err_stat));
1280 			last_time = jiffies;
1281 
1282 			dump_eps(hcd);
1283 		}
1284 	}
1285 #endif
1286 	return 1;
1287 }
1288 
1289 static int
1290 max3421_reset_hcd(struct usb_hcd *hcd)
1291 {
1292 	struct spi_device *spi = to_spi_device(hcd->self.controller);
1293 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1294 	int timeout;
1295 
1296 	/* perform a chip reset and wait for OSCIRQ signal to appear: */
1297 	spi_wr8(hcd, MAX3421_REG_USBCTL, BIT(MAX3421_USBCTL_CHIPRES_BIT));
1298 	/* clear reset: */
1299 	spi_wr8(hcd, MAX3421_REG_USBCTL, 0);
1300 	timeout = 1000;
1301 	while (1) {
1302 		if (spi_rd8(hcd, MAX3421_REG_USBIRQ)
1303 		    & BIT(MAX3421_USBIRQ_OSCOKIRQ_BIT))
1304 			break;
1305 		if (--timeout < 0) {
1306 			dev_err(&spi->dev,
1307 				"timed out waiting for oscillator OK signal");
1308 			return 1;
1309 		}
1310 		cond_resched();
1311 	}
1312 
1313 	/*
1314 	 * Turn on host mode, automatic generation of SOF packets, and
1315 	 * enable pull-down registers on DM/DP:
1316 	 */
1317 	max3421_hcd->mode = (BIT(MAX3421_MODE_HOST_BIT) |
1318 			     BIT(MAX3421_MODE_SOFKAENAB_BIT) |
1319 			     BIT(MAX3421_MODE_DMPULLDN_BIT) |
1320 			     BIT(MAX3421_MODE_DPPULLDN_BIT));
1321 	spi_wr8(hcd, MAX3421_REG_MODE, max3421_hcd->mode);
1322 
1323 	/* reset frame-number: */
1324 	max3421_hcd->frame_number = USB_MAX_FRAME_NUMBER;
1325 	spi_wr8(hcd, MAX3421_REG_HCTL, BIT(MAX3421_HCTL_FRMRST_BIT));
1326 
1327 	/* sample the state of the D+ and D- lines */
1328 	spi_wr8(hcd, MAX3421_REG_HCTL, BIT(MAX3421_HCTL_SAMPLEBUS_BIT));
1329 	max3421_detect_conn(hcd);
1330 
1331 	/* enable frame, connection-detected, and bus-event interrupts: */
1332 	max3421_hcd->hien = (BIT(MAX3421_HI_FRAME_BIT) |
1333 			     BIT(MAX3421_HI_CONDET_BIT) |
1334 			     BIT(MAX3421_HI_BUSEVENT_BIT));
1335 	spi_wr8(hcd, MAX3421_REG_HIEN, max3421_hcd->hien);
1336 
1337 	/* enable interrupts: */
1338 	spi_wr8(hcd, MAX3421_REG_CPUCTL, BIT(MAX3421_CPUCTL_IE_BIT));
1339 	return 1;
1340 }
1341 
1342 static int
1343 max3421_urb_done(struct usb_hcd *hcd)
1344 {
1345 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1346 	unsigned long flags;
1347 	struct urb *urb;
1348 	int status;
1349 
1350 	status = max3421_hcd->urb_done;
1351 	max3421_hcd->urb_done = 0;
1352 	if (status > 0)
1353 		status = 0;
1354 	urb = max3421_hcd->curr_urb;
1355 	if (urb) {
1356 		/* save the old end-points toggles: */
1357 		u8 hrsl = spi_rd8(hcd, MAX3421_REG_HRSL);
1358 		int rcvtog = (hrsl >> MAX3421_HRSL_RCVTOGRD_BIT) & 1;
1359 		int sndtog = (hrsl >> MAX3421_HRSL_SNDTOGRD_BIT) & 1;
1360 		int epnum = usb_endpoint_num(&urb->ep->desc);
1361 
1362 		/* no locking: HCD (i.e., we) own toggles, don't we? */
1363 		usb_settoggle(urb->dev, epnum, 0, rcvtog);
1364 		usb_settoggle(urb->dev, epnum, 1, sndtog);
1365 
1366 		max3421_hcd->curr_urb = NULL;
1367 		spin_lock_irqsave(&max3421_hcd->lock, flags);
1368 		usb_hcd_unlink_urb_from_ep(hcd, urb);
1369 		spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1370 
1371 		/* must be called without the HCD spinlock: */
1372 		usb_hcd_giveback_urb(hcd, urb, status);
1373 	}
1374 	return 1;
1375 }
1376 
1377 static int
1378 max3421_spi_thread(void *dev_id)
1379 {
1380 	struct usb_hcd *hcd = dev_id;
1381 	struct spi_device *spi = to_spi_device(hcd->self.controller);
1382 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1383 	int i, i_worked = 1;
1384 
1385 	/* set full-duplex SPI mode, low-active interrupt pin: */
1386 	spi_wr8(hcd, MAX3421_REG_PINCTL,
1387 		(BIT(MAX3421_PINCTL_FDUPSPI_BIT) |	/* full-duplex */
1388 		 BIT(MAX3421_PINCTL_INTLEVEL_BIT)));	/* low-active irq */
1389 
1390 	while (!kthread_should_stop()) {
1391 		max3421_hcd->rev = spi_rd8(hcd, MAX3421_REG_REVISION);
1392 		if (max3421_hcd->rev == 0x12 || max3421_hcd->rev == 0x13)
1393 			break;
1394 		dev_err(&spi->dev, "bad rev 0x%02x", max3421_hcd->rev);
1395 		msleep(10000);
1396 	}
1397 	dev_info(&spi->dev, "rev 0x%x, SPI clk %dHz, bpw %u, irq %d\n",
1398 		 max3421_hcd->rev, spi->max_speed_hz, spi->bits_per_word,
1399 		 spi->irq);
1400 
1401 	while (!kthread_should_stop()) {
1402 		if (!i_worked) {
1403 			/*
1404 			 * We'll be waiting for wakeups from the hard
1405 			 * interrupt handler, so now is a good time to
1406 			 * sync our hien with the chip:
1407 			 */
1408 			spi_wr8(hcd, MAX3421_REG_HIEN, max3421_hcd->hien);
1409 
1410 			set_current_state(TASK_INTERRUPTIBLE);
1411 			if (test_and_clear_bit(ENABLE_IRQ, &max3421_hcd->todo))
1412 				enable_irq(spi->irq);
1413 			schedule();
1414 			__set_current_state(TASK_RUNNING);
1415 		}
1416 
1417 		i_worked = 0;
1418 
1419 		if (max3421_hcd->urb_done)
1420 			i_worked |= max3421_urb_done(hcd);
1421 		else if (max3421_handle_irqs(hcd))
1422 			i_worked = 1;
1423 		else if (!max3421_hcd->curr_urb)
1424 			i_worked |= max3421_select_and_start_urb(hcd);
1425 
1426 		if (test_and_clear_bit(RESET_HCD, &max3421_hcd->todo))
1427 			/* reset the HCD: */
1428 			i_worked |= max3421_reset_hcd(hcd);
1429 		if (test_and_clear_bit(RESET_PORT, &max3421_hcd->todo)) {
1430 			/* perform a USB bus reset: */
1431 			spi_wr8(hcd, MAX3421_REG_HCTL,
1432 				BIT(MAX3421_HCTL_BUSRST_BIT));
1433 			i_worked = 1;
1434 		}
1435 		if (test_and_clear_bit(CHECK_UNLINK, &max3421_hcd->todo))
1436 			i_worked |= max3421_check_unlink(hcd);
1437 		if (test_and_clear_bit(IOPIN_UPDATE, &max3421_hcd->todo)) {
1438 			/*
1439 			 * IOPINS1/IOPINS2 do not auto-increment, so we can't
1440 			 * use spi_wr_buf().
1441 			 */
1442 			for (i = 0; i < ARRAY_SIZE(max3421_hcd->iopins); ++i) {
1443 				u8 val = spi_rd8(hcd, MAX3421_REG_IOPINS1);
1444 
1445 				val = ((val & 0xf0) |
1446 				       (max3421_hcd->iopins[i] & 0x0f));
1447 				spi_wr8(hcd, MAX3421_REG_IOPINS1 + i, val);
1448 				max3421_hcd->iopins[i] = val;
1449 			}
1450 			i_worked = 1;
1451 		}
1452 	}
1453 	set_current_state(TASK_RUNNING);
1454 	dev_info(&spi->dev, "SPI thread exiting");
1455 	return 0;
1456 }
1457 
1458 static int
1459 max3421_reset_port(struct usb_hcd *hcd)
1460 {
1461 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1462 
1463 	max3421_hcd->port_status &= ~(USB_PORT_STAT_ENABLE |
1464 				      USB_PORT_STAT_LOW_SPEED);
1465 	max3421_hcd->port_status |= USB_PORT_STAT_RESET;
1466 	set_bit(RESET_PORT, &max3421_hcd->todo);
1467 	wake_up_process(max3421_hcd->spi_thread);
1468 	return 0;
1469 }
1470 
1471 static int
1472 max3421_reset(struct usb_hcd *hcd)
1473 {
1474 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1475 
1476 	hcd->self.sg_tablesize = 0;
1477 	hcd->speed = HCD_USB2;
1478 	hcd->self.root_hub->speed = USB_SPEED_FULL;
1479 	set_bit(RESET_HCD, &max3421_hcd->todo);
1480 	wake_up_process(max3421_hcd->spi_thread);
1481 	return 0;
1482 }
1483 
1484 static int
1485 max3421_start(struct usb_hcd *hcd)
1486 {
1487 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1488 
1489 	spin_lock_init(&max3421_hcd->lock);
1490 	max3421_hcd->rh_state = MAX3421_RH_RUNNING;
1491 
1492 	INIT_LIST_HEAD(&max3421_hcd->ep_list);
1493 
1494 	hcd->power_budget = POWER_BUDGET;
1495 	hcd->state = HC_STATE_RUNNING;
1496 	hcd->uses_new_polling = 1;
1497 	return 0;
1498 }
1499 
1500 static void
1501 max3421_stop(struct usb_hcd *hcd)
1502 {
1503 }
1504 
1505 static int
1506 max3421_urb_enqueue(struct usb_hcd *hcd, struct urb *urb, gfp_t mem_flags)
1507 {
1508 	struct spi_device *spi = to_spi_device(hcd->self.controller);
1509 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1510 	struct max3421_ep *max3421_ep;
1511 	unsigned long flags;
1512 	int retval;
1513 
1514 	switch (usb_pipetype(urb->pipe)) {
1515 	case PIPE_INTERRUPT:
1516 	case PIPE_ISOCHRONOUS:
1517 		if (urb->interval < 0) {
1518 			dev_err(&spi->dev,
1519 			  "%s: interval=%d for intr-/iso-pipe; expected > 0\n",
1520 				__func__, urb->interval);
1521 			return -EINVAL;
1522 		}
1523 		break;
1524 	default:
1525 		break;
1526 	}
1527 
1528 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1529 
1530 	max3421_ep = urb->ep->hcpriv;
1531 	if (!max3421_ep) {
1532 		/* gets freed in max3421_endpoint_disable: */
1533 		max3421_ep = kzalloc(sizeof(struct max3421_ep), GFP_ATOMIC);
1534 		if (!max3421_ep) {
1535 			retval = -ENOMEM;
1536 			goto out;
1537 		}
1538 		max3421_ep->ep = urb->ep;
1539 		max3421_ep->last_active = max3421_hcd->frame_number;
1540 		urb->ep->hcpriv = max3421_ep;
1541 
1542 		list_add_tail(&max3421_ep->ep_list, &max3421_hcd->ep_list);
1543 	}
1544 
1545 	retval = usb_hcd_link_urb_to_ep(hcd, urb);
1546 	if (retval == 0) {
1547 		/* Since we added to the queue, restart scheduling: */
1548 		max3421_hcd->sched_pass = SCHED_PASS_PERIODIC;
1549 		wake_up_process(max3421_hcd->spi_thread);
1550 	}
1551 
1552 out:
1553 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1554 	return retval;
1555 }
1556 
1557 static int
1558 max3421_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
1559 {
1560 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1561 	unsigned long flags;
1562 	int retval;
1563 
1564 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1565 
1566 	/*
1567 	 * This will set urb->unlinked which in turn causes the entry
1568 	 * to be dropped at the next opportunity.
1569 	 */
1570 	retval = usb_hcd_check_unlink_urb(hcd, urb, status);
1571 	if (retval == 0) {
1572 		set_bit(CHECK_UNLINK, &max3421_hcd->todo);
1573 		wake_up_process(max3421_hcd->spi_thread);
1574 	}
1575 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1576 	return retval;
1577 }
1578 
1579 static void
1580 max3421_endpoint_disable(struct usb_hcd *hcd, struct usb_host_endpoint *ep)
1581 {
1582 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1583 	unsigned long flags;
1584 
1585 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1586 
1587 	if (ep->hcpriv) {
1588 		struct max3421_ep *max3421_ep = ep->hcpriv;
1589 
1590 		/* remove myself from the ep_list: */
1591 		if (!list_empty(&max3421_ep->ep_list))
1592 			list_del(&max3421_ep->ep_list);
1593 		kfree(max3421_ep);
1594 		ep->hcpriv = NULL;
1595 	}
1596 
1597 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1598 }
1599 
1600 static int
1601 max3421_get_frame_number(struct usb_hcd *hcd)
1602 {
1603 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1604 	return max3421_hcd->frame_number;
1605 }
1606 
1607 /*
1608  * Should return a non-zero value when any port is undergoing a resume
1609  * transition while the root hub is suspended.
1610  */
1611 static int
1612 max3421_hub_status_data(struct usb_hcd *hcd, char *buf)
1613 {
1614 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1615 	unsigned long flags;
1616 	int retval = 0;
1617 
1618 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1619 	if (!HCD_HW_ACCESSIBLE(hcd))
1620 		goto done;
1621 
1622 	*buf = 0;
1623 	if ((max3421_hcd->port_status & PORT_C_MASK) != 0) {
1624 		*buf = (1 << 1); /* a hub over-current condition exists */
1625 		dev_dbg(hcd->self.controller,
1626 			"port status 0x%08x has changes\n",
1627 			max3421_hcd->port_status);
1628 		retval = 1;
1629 		if (max3421_hcd->rh_state == MAX3421_RH_SUSPENDED)
1630 			usb_hcd_resume_root_hub(hcd);
1631 	}
1632 done:
1633 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1634 	return retval;
1635 }
1636 
1637 static inline void
1638 hub_descriptor(struct usb_hub_descriptor *desc)
1639 {
1640 	memset(desc, 0, sizeof(*desc));
1641 	/*
1642 	 * See Table 11-13: Hub Descriptor in USB 2.0 spec.
1643 	 */
1644 	desc->bDescriptorType = USB_DT_HUB; /* hub descriptor */
1645 	desc->bDescLength = 9;
1646 	desc->wHubCharacteristics = cpu_to_le16(HUB_CHAR_INDV_PORT_LPSM |
1647 						HUB_CHAR_COMMON_OCPM);
1648 	desc->bNbrPorts = 1;
1649 }
1650 
1651 /*
1652  * Set the MAX3421E general-purpose output with number PIN_NUMBER to
1653  * VALUE (0 or 1).  PIN_NUMBER may be in the range from 1-8.  For
1654  * any other value, this function acts as a no-op.
1655  */
1656 static void
1657 max3421_gpout_set_value(struct usb_hcd *hcd, u8 pin_number, u8 value)
1658 {
1659 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1660 	u8 mask, idx;
1661 
1662 	--pin_number;
1663 	if (pin_number >= MAX3421_GPOUT_COUNT)
1664 		return;
1665 
1666 	mask = 1u << (pin_number % 4);
1667 	idx = pin_number / 4;
1668 
1669 	if (value)
1670 		max3421_hcd->iopins[idx] |=  mask;
1671 	else
1672 		max3421_hcd->iopins[idx] &= ~mask;
1673 	set_bit(IOPIN_UPDATE, &max3421_hcd->todo);
1674 	wake_up_process(max3421_hcd->spi_thread);
1675 }
1676 
1677 static int
1678 max3421_hub_control(struct usb_hcd *hcd, u16 type_req, u16 value, u16 index,
1679 		    char *buf, u16 length)
1680 {
1681 	struct spi_device *spi = to_spi_device(hcd->self.controller);
1682 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1683 	struct max3421_hcd_platform_data *pdata;
1684 	unsigned long flags;
1685 	int retval = 0;
1686 
1687 	pdata = spi->dev.platform_data;
1688 
1689 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1690 
1691 	switch (type_req) {
1692 	case ClearHubFeature:
1693 		break;
1694 	case ClearPortFeature:
1695 		switch (value) {
1696 		case USB_PORT_FEAT_SUSPEND:
1697 			break;
1698 		case USB_PORT_FEAT_POWER:
1699 			dev_dbg(hcd->self.controller, "power-off\n");
1700 			max3421_gpout_set_value(hcd, pdata->vbus_gpout,
1701 						!pdata->vbus_active_level);
1702 			fallthrough;
1703 		default:
1704 			max3421_hcd->port_status &= ~(1 << value);
1705 		}
1706 		break;
1707 	case GetHubDescriptor:
1708 		hub_descriptor((struct usb_hub_descriptor *) buf);
1709 		break;
1710 
1711 	case DeviceRequest | USB_REQ_GET_DESCRIPTOR:
1712 	case GetPortErrorCount:
1713 	case SetHubDepth:
1714 		/* USB3 only */
1715 		goto error;
1716 
1717 	case GetHubStatus:
1718 		*(__le32 *) buf = cpu_to_le32(0);
1719 		break;
1720 
1721 	case GetPortStatus:
1722 		if (index != 1) {
1723 			retval = -EPIPE;
1724 			goto error;
1725 		}
1726 		((__le16 *) buf)[0] = cpu_to_le16(max3421_hcd->port_status);
1727 		((__le16 *) buf)[1] =
1728 			cpu_to_le16(max3421_hcd->port_status >> 16);
1729 		break;
1730 
1731 	case SetHubFeature:
1732 		retval = -EPIPE;
1733 		break;
1734 
1735 	case SetPortFeature:
1736 		switch (value) {
1737 		case USB_PORT_FEAT_LINK_STATE:
1738 		case USB_PORT_FEAT_U1_TIMEOUT:
1739 		case USB_PORT_FEAT_U2_TIMEOUT:
1740 		case USB_PORT_FEAT_BH_PORT_RESET:
1741 			goto error;
1742 		case USB_PORT_FEAT_SUSPEND:
1743 			if (max3421_hcd->active)
1744 				max3421_hcd->port_status |=
1745 					USB_PORT_STAT_SUSPEND;
1746 			break;
1747 		case USB_PORT_FEAT_POWER:
1748 			dev_dbg(hcd->self.controller, "power-on\n");
1749 			max3421_hcd->port_status |= USB_PORT_STAT_POWER;
1750 			max3421_gpout_set_value(hcd, pdata->vbus_gpout,
1751 						pdata->vbus_active_level);
1752 			break;
1753 		case USB_PORT_FEAT_RESET:
1754 			max3421_reset_port(hcd);
1755 			fallthrough;
1756 		default:
1757 			if ((max3421_hcd->port_status & USB_PORT_STAT_POWER)
1758 			    != 0)
1759 				max3421_hcd->port_status |= (1 << value);
1760 		}
1761 		break;
1762 
1763 	default:
1764 		dev_dbg(hcd->self.controller,
1765 			"hub control req%04x v%04x i%04x l%d\n",
1766 			type_req, value, index, length);
1767 error:		/* "protocol stall" on error */
1768 		retval = -EPIPE;
1769 	}
1770 
1771 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1772 	return retval;
1773 }
1774 
1775 static int
1776 max3421_bus_suspend(struct usb_hcd *hcd)
1777 {
1778 	return -1;
1779 }
1780 
1781 static int
1782 max3421_bus_resume(struct usb_hcd *hcd)
1783 {
1784 	return -1;
1785 }
1786 
1787 static const struct hc_driver max3421_hcd_desc = {
1788 	.description =		"max3421",
1789 	.product_desc =		DRIVER_DESC,
1790 	.hcd_priv_size =	sizeof(struct max3421_hcd),
1791 	.flags =		HCD_USB11,
1792 	.reset =		max3421_reset,
1793 	.start =		max3421_start,
1794 	.stop =			max3421_stop,
1795 	.get_frame_number =	max3421_get_frame_number,
1796 	.urb_enqueue =		max3421_urb_enqueue,
1797 	.urb_dequeue =		max3421_urb_dequeue,
1798 	.endpoint_disable =	max3421_endpoint_disable,
1799 	.hub_status_data =	max3421_hub_status_data,
1800 	.hub_control =		max3421_hub_control,
1801 	.bus_suspend =		max3421_bus_suspend,
1802 	.bus_resume =		max3421_bus_resume,
1803 };
1804 
1805 static int
1806 max3421_of_vbus_en_pin(struct device *dev, struct max3421_hcd_platform_data *pdata)
1807 {
1808 	int retval;
1809 	uint32_t value[2];
1810 
1811 	if (!pdata)
1812 		return -EINVAL;
1813 
1814 	retval = of_property_read_u32_array(dev->of_node, "maxim,vbus-en-pin", value, 2);
1815 	if (retval) {
1816 		dev_err(dev, "device tree node property 'maxim,vbus-en-pin' is missing\n");
1817 		return retval;
1818 	}
1819 	dev_info(dev, "property 'maxim,vbus-en-pin' value is <%d %d>\n", value[0], value[1]);
1820 
1821 	pdata->vbus_gpout = value[0];
1822 	pdata->vbus_active_level = value[1];
1823 
1824 	return 0;
1825 }
1826 
1827 static int
1828 max3421_probe(struct spi_device *spi)
1829 {
1830 	struct device *dev = &spi->dev;
1831 	struct max3421_hcd *max3421_hcd;
1832 	struct usb_hcd *hcd = NULL;
1833 	struct max3421_hcd_platform_data *pdata = NULL;
1834 	int retval;
1835 
1836 	if (spi_setup(spi) < 0) {
1837 		dev_err(&spi->dev, "Unable to setup SPI bus");
1838 		return -EFAULT;
1839 	}
1840 
1841 	if (!spi->irq) {
1842 		dev_err(dev, "Failed to get SPI IRQ");
1843 		return -EFAULT;
1844 	}
1845 
1846 	if (IS_ENABLED(CONFIG_OF) && dev->of_node) {
1847 		pdata = devm_kzalloc(&spi->dev, sizeof(*pdata), GFP_KERNEL);
1848 		if (!pdata) {
1849 			retval = -ENOMEM;
1850 			goto error;
1851 		}
1852 		retval = max3421_of_vbus_en_pin(dev, pdata);
1853 		if (retval)
1854 			goto error;
1855 
1856 		spi->dev.platform_data = pdata;
1857 	}
1858 
1859 	pdata = spi->dev.platform_data;
1860 	if (!pdata) {
1861 		dev_err(&spi->dev, "driver configuration data is not provided\n");
1862 		retval = -EFAULT;
1863 		goto error;
1864 	}
1865 	if (pdata->vbus_active_level > 1) {
1866 		dev_err(&spi->dev, "vbus active level value %d is out of range (0/1)\n", pdata->vbus_active_level);
1867 		retval = -EINVAL;
1868 		goto error;
1869 	}
1870 	if (pdata->vbus_gpout < 1 || pdata->vbus_gpout > MAX3421_GPOUT_COUNT) {
1871 		dev_err(&spi->dev, "vbus gpout value %d is out of range (1..8)\n", pdata->vbus_gpout);
1872 		retval = -EINVAL;
1873 		goto error;
1874 	}
1875 
1876 	retval = -ENOMEM;
1877 	hcd = usb_create_hcd(&max3421_hcd_desc, &spi->dev,
1878 			     dev_name(&spi->dev));
1879 	if (!hcd) {
1880 		dev_err(&spi->dev, "failed to create HCD structure\n");
1881 		goto error;
1882 	}
1883 	set_bit(HCD_FLAG_POLL_RH, &hcd->flags);
1884 	max3421_hcd = hcd_to_max3421(hcd);
1885 	max3421_hcd->next = max3421_hcd_list;
1886 	max3421_hcd_list = max3421_hcd;
1887 	INIT_LIST_HEAD(&max3421_hcd->ep_list);
1888 
1889 	max3421_hcd->tx = kmalloc(sizeof(*max3421_hcd->tx), GFP_KERNEL);
1890 	if (!max3421_hcd->tx)
1891 		goto error;
1892 	max3421_hcd->rx = kmalloc(sizeof(*max3421_hcd->rx), GFP_KERNEL);
1893 	if (!max3421_hcd->rx)
1894 		goto error;
1895 
1896 	max3421_hcd->spi_thread = kthread_run(max3421_spi_thread, hcd,
1897 					      "max3421_spi_thread");
1898 	if (max3421_hcd->spi_thread == ERR_PTR(-ENOMEM)) {
1899 		dev_err(&spi->dev,
1900 			"failed to create SPI thread (out of memory)\n");
1901 		goto error;
1902 	}
1903 
1904 	retval = usb_add_hcd(hcd, 0, 0);
1905 	if (retval) {
1906 		dev_err(&spi->dev, "failed to add HCD\n");
1907 		goto error;
1908 	}
1909 
1910 	retval = request_irq(spi->irq, max3421_irq_handler,
1911 			     IRQF_TRIGGER_LOW, "max3421", hcd);
1912 	if (retval < 0) {
1913 		dev_err(&spi->dev, "failed to request irq %d\n", spi->irq);
1914 		goto error;
1915 	}
1916 	return 0;
1917 
1918 error:
1919 	if (IS_ENABLED(CONFIG_OF) && dev->of_node && pdata) {
1920 		devm_kfree(&spi->dev, pdata);
1921 		spi->dev.platform_data = NULL;
1922 	}
1923 
1924 	if (hcd) {
1925 		kfree(max3421_hcd->tx);
1926 		kfree(max3421_hcd->rx);
1927 		if (max3421_hcd->spi_thread)
1928 			kthread_stop(max3421_hcd->spi_thread);
1929 		usb_put_hcd(hcd);
1930 	}
1931 	return retval;
1932 }
1933 
1934 static int
1935 max3421_remove(struct spi_device *spi)
1936 {
1937 	struct max3421_hcd *max3421_hcd = NULL, **prev;
1938 	struct usb_hcd *hcd = NULL;
1939 	unsigned long flags;
1940 
1941 	for (prev = &max3421_hcd_list; *prev; prev = &(*prev)->next) {
1942 		max3421_hcd = *prev;
1943 		hcd = max3421_to_hcd(max3421_hcd);
1944 		if (hcd->self.controller == &spi->dev)
1945 			break;
1946 	}
1947 	if (!max3421_hcd) {
1948 		dev_err(&spi->dev, "no MAX3421 HCD found for SPI device %p\n",
1949 			spi);
1950 		return -ENODEV;
1951 	}
1952 
1953 	usb_remove_hcd(hcd);
1954 
1955 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1956 
1957 	kthread_stop(max3421_hcd->spi_thread);
1958 	*prev = max3421_hcd->next;
1959 
1960 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1961 
1962 	free_irq(spi->irq, hcd);
1963 
1964 	usb_put_hcd(hcd);
1965 	return 0;
1966 }
1967 
1968 static const struct of_device_id max3421_of_match_table[] = {
1969 	{ .compatible = "maxim,max3421", },
1970 	{},
1971 };
1972 MODULE_DEVICE_TABLE(of, max3421_of_match_table);
1973 
1974 static struct spi_driver max3421_driver = {
1975 	.probe		= max3421_probe,
1976 	.remove		= max3421_remove,
1977 	.driver		= {
1978 		.name	= "max3421-hcd",
1979 		.of_match_table = of_match_ptr(max3421_of_match_table),
1980 	},
1981 };
1982 
1983 module_spi_driver(max3421_driver);
1984 
1985 MODULE_DESCRIPTION(DRIVER_DESC);
1986 MODULE_AUTHOR("David Mosberger <davidm@egauge.net>");
1987 MODULE_LICENSE("GPL");
1988