xref: /openbmc/linux/drivers/usb/host/max3421-hcd.c (revision c7e1962a)
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 #define POWER_BUDGET	500	/* in mA; use 8 for low-power port testing */
76 
77 /* Port-change mask: */
78 #define PORT_C_MASK	((USB_PORT_STAT_C_CONNECTION |	\
79 			  USB_PORT_STAT_C_ENABLE |	\
80 			  USB_PORT_STAT_C_SUSPEND |	\
81 			  USB_PORT_STAT_C_OVERCURRENT | \
82 			  USB_PORT_STAT_C_RESET) << 16)
83 
84 #define MAX3421_GPOUT_COUNT	8
85 
86 enum max3421_rh_state {
87 	MAX3421_RH_RESET,
88 	MAX3421_RH_SUSPENDED,
89 	MAX3421_RH_RUNNING
90 };
91 
92 enum pkt_state {
93 	PKT_STATE_SETUP,	/* waiting to send setup packet to ctrl pipe */
94 	PKT_STATE_TRANSFER,	/* waiting to xfer transfer_buffer */
95 	PKT_STATE_TERMINATE	/* waiting to terminate control transfer */
96 };
97 
98 enum scheduling_pass {
99 	SCHED_PASS_PERIODIC,
100 	SCHED_PASS_NON_PERIODIC,
101 	SCHED_PASS_DONE
102 };
103 
104 /* Bit numbers for max3421_hcd->todo: */
105 enum {
106 	ENABLE_IRQ = 0,
107 	RESET_HCD,
108 	RESET_PORT,
109 	CHECK_UNLINK,
110 	IOPIN_UPDATE
111 };
112 
113 struct max3421_dma_buf {
114 	u8 data[2];
115 };
116 
117 struct max3421_hcd {
118 	spinlock_t lock;
119 
120 	struct task_struct *spi_thread;
121 
122 	enum max3421_rh_state rh_state;
123 	/* lower 16 bits contain port status, upper 16 bits the change mask: */
124 	u32 port_status;
125 
126 	unsigned active:1;
127 
128 	struct list_head ep_list;	/* list of EP's with work */
129 
130 	/*
131 	 * The following are owned by spi_thread (may be accessed by
132 	 * SPI-thread without acquiring the HCD lock:
133 	 */
134 	u8 rev;				/* chip revision */
135 	u16 frame_number;
136 	/*
137 	 * kmalloc'd buffers guaranteed to be in separate (DMA)
138 	 * cache-lines:
139 	 */
140 	struct max3421_dma_buf *tx;
141 	struct max3421_dma_buf *rx;
142 	/*
143 	 * URB we're currently processing.  Must not be reset to NULL
144 	 * unless MAX3421E chip is idle:
145 	 */
146 	struct urb *curr_urb;
147 	enum scheduling_pass sched_pass;
148 	int urb_done;			/* > 0 -> no errors, < 0: errno */
149 	size_t curr_len;
150 	u8 hien;
151 	u8 mode;
152 	u8 iopins[2];
153 	unsigned long todo;
154 #ifdef DEBUG
155 	unsigned long err_stat[16];
156 #endif
157 };
158 
159 struct max3421_ep {
160 	struct usb_host_endpoint *ep;
161 	struct list_head ep_list;
162 	u32 naks;
163 	u16 last_active;		/* frame # this ep was last active */
164 	enum pkt_state pkt_state;
165 	u8 retries;
166 	u8 retransmit;			/* packet needs retransmission */
167 };
168 
169 #define MAX3421_FIFO_SIZE	64
170 
171 #define MAX3421_SPI_DIR_RD	0	/* read register from MAX3421 */
172 #define MAX3421_SPI_DIR_WR	1	/* write register to MAX3421 */
173 
174 /* SPI commands: */
175 #define MAX3421_SPI_DIR_SHIFT	1
176 #define MAX3421_SPI_REG_SHIFT	3
177 
178 #define MAX3421_REG_RCVFIFO	1
179 #define MAX3421_REG_SNDFIFO	2
180 #define MAX3421_REG_SUDFIFO	4
181 #define MAX3421_REG_RCVBC	6
182 #define MAX3421_REG_SNDBC	7
183 #define MAX3421_REG_USBIRQ	13
184 #define MAX3421_REG_USBIEN	14
185 #define MAX3421_REG_USBCTL	15
186 #define MAX3421_REG_CPUCTL	16
187 #define MAX3421_REG_PINCTL	17
188 #define MAX3421_REG_REVISION	18
189 #define MAX3421_REG_IOPINS1	20
190 #define MAX3421_REG_IOPINS2	21
191 #define MAX3421_REG_GPINIRQ	22
192 #define MAX3421_REG_GPINIEN	23
193 #define MAX3421_REG_GPINPOL	24
194 #define MAX3421_REG_HIRQ	25
195 #define MAX3421_REG_HIEN	26
196 #define MAX3421_REG_MODE	27
197 #define MAX3421_REG_PERADDR	28
198 #define MAX3421_REG_HCTL	29
199 #define MAX3421_REG_HXFR	30
200 #define MAX3421_REG_HRSL	31
201 
202 enum {
203 	MAX3421_USBIRQ_OSCOKIRQ_BIT = 0,
204 	MAX3421_USBIRQ_NOVBUSIRQ_BIT = 5,
205 	MAX3421_USBIRQ_VBUSIRQ_BIT
206 };
207 
208 enum {
209 	MAX3421_CPUCTL_IE_BIT = 0,
210 	MAX3421_CPUCTL_PULSEWID0_BIT = 6,
211 	MAX3421_CPUCTL_PULSEWID1_BIT
212 };
213 
214 enum {
215 	MAX3421_USBCTL_PWRDOWN_BIT = 4,
216 	MAX3421_USBCTL_CHIPRES_BIT
217 };
218 
219 enum {
220 	MAX3421_PINCTL_GPXA_BIT	= 0,
221 	MAX3421_PINCTL_GPXB_BIT,
222 	MAX3421_PINCTL_POSINT_BIT,
223 	MAX3421_PINCTL_INTLEVEL_BIT,
224 	MAX3421_PINCTL_FDUPSPI_BIT,
225 	MAX3421_PINCTL_EP0INAK_BIT,
226 	MAX3421_PINCTL_EP2INAK_BIT,
227 	MAX3421_PINCTL_EP3INAK_BIT,
228 };
229 
230 enum {
231 	MAX3421_HI_BUSEVENT_BIT = 0,	/* bus-reset/-resume */
232 	MAX3421_HI_RWU_BIT,		/* remote wakeup */
233 	MAX3421_HI_RCVDAV_BIT,		/* receive FIFO data available */
234 	MAX3421_HI_SNDBAV_BIT,		/* send buffer available */
235 	MAX3421_HI_SUSDN_BIT,		/* suspend operation done */
236 	MAX3421_HI_CONDET_BIT,		/* peripheral connect/disconnect */
237 	MAX3421_HI_FRAME_BIT,		/* frame generator */
238 	MAX3421_HI_HXFRDN_BIT,		/* host transfer done */
239 };
240 
241 enum {
242 	MAX3421_HCTL_BUSRST_BIT = 0,
243 	MAX3421_HCTL_FRMRST_BIT,
244 	MAX3421_HCTL_SAMPLEBUS_BIT,
245 	MAX3421_HCTL_SIGRSM_BIT,
246 	MAX3421_HCTL_RCVTOG0_BIT,
247 	MAX3421_HCTL_RCVTOG1_BIT,
248 	MAX3421_HCTL_SNDTOG0_BIT,
249 	MAX3421_HCTL_SNDTOG1_BIT
250 };
251 
252 enum {
253 	MAX3421_MODE_HOST_BIT = 0,
254 	MAX3421_MODE_LOWSPEED_BIT,
255 	MAX3421_MODE_HUBPRE_BIT,
256 	MAX3421_MODE_SOFKAENAB_BIT,
257 	MAX3421_MODE_SEPIRQ_BIT,
258 	MAX3421_MODE_DELAYISO_BIT,
259 	MAX3421_MODE_DMPULLDN_BIT,
260 	MAX3421_MODE_DPPULLDN_BIT
261 };
262 
263 enum {
264 	MAX3421_HRSL_OK = 0,
265 	MAX3421_HRSL_BUSY,
266 	MAX3421_HRSL_BADREQ,
267 	MAX3421_HRSL_UNDEF,
268 	MAX3421_HRSL_NAK,
269 	MAX3421_HRSL_STALL,
270 	MAX3421_HRSL_TOGERR,
271 	MAX3421_HRSL_WRONGPID,
272 	MAX3421_HRSL_BADBC,
273 	MAX3421_HRSL_PIDERR,
274 	MAX3421_HRSL_PKTERR,
275 	MAX3421_HRSL_CRCERR,
276 	MAX3421_HRSL_KERR,
277 	MAX3421_HRSL_JERR,
278 	MAX3421_HRSL_TIMEOUT,
279 	MAX3421_HRSL_BABBLE,
280 	MAX3421_HRSL_RESULT_MASK = 0xf,
281 	MAX3421_HRSL_RCVTOGRD_BIT = 4,
282 	MAX3421_HRSL_SNDTOGRD_BIT,
283 	MAX3421_HRSL_KSTATUS_BIT,
284 	MAX3421_HRSL_JSTATUS_BIT
285 };
286 
287 /* Return same error-codes as ohci.h:cc_to_error: */
288 static const int hrsl_to_error[] = {
289 	[MAX3421_HRSL_OK] =		0,
290 	[MAX3421_HRSL_BUSY] =		-EINVAL,
291 	[MAX3421_HRSL_BADREQ] =		-EINVAL,
292 	[MAX3421_HRSL_UNDEF] =		-EINVAL,
293 	[MAX3421_HRSL_NAK] =		-EAGAIN,
294 	[MAX3421_HRSL_STALL] =		-EPIPE,
295 	[MAX3421_HRSL_TOGERR] =		-EILSEQ,
296 	[MAX3421_HRSL_WRONGPID] =	-EPROTO,
297 	[MAX3421_HRSL_BADBC] =		-EREMOTEIO,
298 	[MAX3421_HRSL_PIDERR] =		-EPROTO,
299 	[MAX3421_HRSL_PKTERR] =		-EPROTO,
300 	[MAX3421_HRSL_CRCERR] =		-EILSEQ,
301 	[MAX3421_HRSL_KERR] =		-EIO,
302 	[MAX3421_HRSL_JERR] =		-EIO,
303 	[MAX3421_HRSL_TIMEOUT] =	-ETIME,
304 	[MAX3421_HRSL_BABBLE] =		-EOVERFLOW
305 };
306 
307 /*
308  * See https://www.beyondlogic.org/usbnutshell/usb4.shtml#Control for a
309  * reasonable overview of how control transfers use the IN/OUT
310  * tokens.
311  */
312 #define MAX3421_HXFR_BULK_IN(ep)	(0x00 | (ep))	/* bulk or interrupt */
313 #define MAX3421_HXFR_SETUP		 0x10
314 #define MAX3421_HXFR_BULK_OUT(ep)	(0x20 | (ep))	/* bulk or interrupt */
315 #define MAX3421_HXFR_ISO_IN(ep)		(0x40 | (ep))
316 #define MAX3421_HXFR_ISO_OUT(ep)	(0x60 | (ep))
317 #define MAX3421_HXFR_HS_IN		 0x80		/* handshake in */
318 #define MAX3421_HXFR_HS_OUT		 0xa0		/* handshake out */
319 
320 #define field(val, bit)	((val) << (bit))
321 
322 static inline s16
323 frame_diff(u16 left, u16 right)
324 {
325 	return ((unsigned) (left - right)) % (USB_MAX_FRAME_NUMBER + 1);
326 }
327 
328 static inline struct max3421_hcd *
329 hcd_to_max3421(struct usb_hcd *hcd)
330 {
331 	return (struct max3421_hcd *) hcd->hcd_priv;
332 }
333 
334 static inline struct usb_hcd *
335 max3421_to_hcd(struct max3421_hcd *max3421_hcd)
336 {
337 	return container_of((void *) max3421_hcd, struct usb_hcd, hcd_priv);
338 }
339 
340 static u8
341 spi_rd8(struct usb_hcd *hcd, unsigned int reg)
342 {
343 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
344 	struct spi_device *spi = to_spi_device(hcd->self.controller);
345 	struct spi_transfer transfer;
346 	struct spi_message msg;
347 
348 	memset(&transfer, 0, sizeof(transfer));
349 
350 	spi_message_init(&msg);
351 
352 	max3421_hcd->tx->data[0] =
353 		(field(reg, MAX3421_SPI_REG_SHIFT) |
354 		 field(MAX3421_SPI_DIR_RD, MAX3421_SPI_DIR_SHIFT));
355 
356 	transfer.tx_buf = max3421_hcd->tx->data;
357 	transfer.rx_buf = max3421_hcd->rx->data;
358 	transfer.len = 2;
359 
360 	spi_message_add_tail(&transfer, &msg);
361 	spi_sync(spi, &msg);
362 
363 	return max3421_hcd->rx->data[1];
364 }
365 
366 static void
367 spi_wr8(struct usb_hcd *hcd, unsigned int reg, u8 val)
368 {
369 	struct spi_device *spi = to_spi_device(hcd->self.controller);
370 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
371 	struct spi_transfer transfer;
372 	struct spi_message msg;
373 
374 	memset(&transfer, 0, sizeof(transfer));
375 
376 	spi_message_init(&msg);
377 
378 	max3421_hcd->tx->data[0] =
379 		(field(reg, MAX3421_SPI_REG_SHIFT) |
380 		 field(MAX3421_SPI_DIR_WR, MAX3421_SPI_DIR_SHIFT));
381 	max3421_hcd->tx->data[1] = val;
382 
383 	transfer.tx_buf = max3421_hcd->tx->data;
384 	transfer.len = 2;
385 
386 	spi_message_add_tail(&transfer, &msg);
387 	spi_sync(spi, &msg);
388 }
389 
390 static void
391 spi_rd_buf(struct usb_hcd *hcd, unsigned int reg, void *buf, size_t len)
392 {
393 	struct spi_device *spi = to_spi_device(hcd->self.controller);
394 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
395 	struct spi_transfer transfer[2];
396 	struct spi_message msg;
397 
398 	memset(transfer, 0, sizeof(transfer));
399 
400 	spi_message_init(&msg);
401 
402 	max3421_hcd->tx->data[0] =
403 		(field(reg, MAX3421_SPI_REG_SHIFT) |
404 		 field(MAX3421_SPI_DIR_RD, MAX3421_SPI_DIR_SHIFT));
405 	transfer[0].tx_buf = max3421_hcd->tx->data;
406 	transfer[0].len = 1;
407 
408 	transfer[1].rx_buf = buf;
409 	transfer[1].len = len;
410 
411 	spi_message_add_tail(&transfer[0], &msg);
412 	spi_message_add_tail(&transfer[1], &msg);
413 	spi_sync(spi, &msg);
414 }
415 
416 static void
417 spi_wr_buf(struct usb_hcd *hcd, unsigned int reg, void *buf, size_t len)
418 {
419 	struct spi_device *spi = to_spi_device(hcd->self.controller);
420 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
421 	struct spi_transfer transfer[2];
422 	struct spi_message msg;
423 
424 	memset(transfer, 0, sizeof(transfer));
425 
426 	spi_message_init(&msg);
427 
428 	max3421_hcd->tx->data[0] =
429 		(field(reg, MAX3421_SPI_REG_SHIFT) |
430 		 field(MAX3421_SPI_DIR_WR, MAX3421_SPI_DIR_SHIFT));
431 
432 	transfer[0].tx_buf = max3421_hcd->tx->data;
433 	transfer[0].len = 1;
434 
435 	transfer[1].tx_buf = buf;
436 	transfer[1].len = len;
437 
438 	spi_message_add_tail(&transfer[0], &msg);
439 	spi_message_add_tail(&transfer[1], &msg);
440 	spi_sync(spi, &msg);
441 }
442 
443 /*
444  * Figure out the correct setting for the LOWSPEED and HUBPRE mode
445  * bits.  The HUBPRE bit needs to be set when MAX3421E operates at
446  * full speed, but it's talking to a low-speed device (i.e., through a
447  * hub).  Setting that bit ensures that every low-speed packet is
448  * preceded by a full-speed PRE PID.  Possible configurations:
449  *
450  * Hub speed:	Device speed:	=>	LOWSPEED bit:	HUBPRE bit:
451  *	FULL	FULL		=>	0		0
452  *	FULL	LOW		=>	1		1
453  *	LOW	LOW		=>	1		0
454  *	LOW	FULL		=>	1		0
455  */
456 static void
457 max3421_set_speed(struct usb_hcd *hcd, struct usb_device *dev)
458 {
459 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
460 	u8 mode_lowspeed, mode_hubpre, mode = max3421_hcd->mode;
461 
462 	mode_lowspeed = BIT(MAX3421_MODE_LOWSPEED_BIT);
463 	mode_hubpre   = BIT(MAX3421_MODE_HUBPRE_BIT);
464 	if (max3421_hcd->port_status & USB_PORT_STAT_LOW_SPEED) {
465 		mode |=  mode_lowspeed;
466 		mode &= ~mode_hubpre;
467 	} else if (dev->speed == USB_SPEED_LOW) {
468 		mode |= mode_lowspeed | mode_hubpre;
469 	} else {
470 		mode &= ~(mode_lowspeed | mode_hubpre);
471 	}
472 	if (mode != max3421_hcd->mode) {
473 		max3421_hcd->mode = mode;
474 		spi_wr8(hcd, MAX3421_REG_MODE, max3421_hcd->mode);
475 	}
476 
477 }
478 
479 /*
480  * Caller must NOT hold HCD spinlock.
481  */
482 static void
483 max3421_set_address(struct usb_hcd *hcd, struct usb_device *dev, int epnum)
484 {
485 	int rcvtog, sndtog;
486 	u8 hctl;
487 
488 	/* setup new endpoint's toggle bits: */
489 	rcvtog = usb_gettoggle(dev, epnum, 0);
490 	sndtog = usb_gettoggle(dev, epnum, 1);
491 	hctl = (BIT(rcvtog + MAX3421_HCTL_RCVTOG0_BIT) |
492 		BIT(sndtog + MAX3421_HCTL_SNDTOG0_BIT));
493 
494 	spi_wr8(hcd, MAX3421_REG_HCTL, hctl);
495 
496 	/*
497 	 * Note: devnum for one and the same device can change during
498 	 * address-assignment so it's best to just always load the
499 	 * address whenever the end-point changed/was forced.
500 	 */
501 	spi_wr8(hcd, MAX3421_REG_PERADDR, dev->devnum);
502 }
503 
504 static int
505 max3421_ctrl_setup(struct usb_hcd *hcd, struct urb *urb)
506 {
507 	spi_wr_buf(hcd, MAX3421_REG_SUDFIFO, urb->setup_packet, 8);
508 	return MAX3421_HXFR_SETUP;
509 }
510 
511 static int
512 max3421_transfer_in(struct usb_hcd *hcd, struct urb *urb)
513 {
514 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
515 	int epnum = usb_pipeendpoint(urb->pipe);
516 
517 	max3421_hcd->curr_len = 0;
518 	max3421_hcd->hien |= BIT(MAX3421_HI_RCVDAV_BIT);
519 	return MAX3421_HXFR_BULK_IN(epnum);
520 }
521 
522 static int
523 max3421_transfer_out(struct usb_hcd *hcd, struct urb *urb, int fast_retransmit)
524 {
525 	struct spi_device *spi = to_spi_device(hcd->self.controller);
526 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
527 	int epnum = usb_pipeendpoint(urb->pipe);
528 	u32 max_packet;
529 	void *src;
530 
531 	src = urb->transfer_buffer + urb->actual_length;
532 
533 	if (fast_retransmit) {
534 		if (max3421_hcd->rev == 0x12) {
535 			/* work around rev 0x12 bug: */
536 			spi_wr8(hcd, MAX3421_REG_SNDBC, 0);
537 			spi_wr8(hcd, MAX3421_REG_SNDFIFO, ((u8 *) src)[0]);
538 			spi_wr8(hcd, MAX3421_REG_SNDBC, max3421_hcd->curr_len);
539 		}
540 		return MAX3421_HXFR_BULK_OUT(epnum);
541 	}
542 
543 	max_packet = usb_maxpacket(urb->dev, urb->pipe);
544 
545 	if (max_packet > MAX3421_FIFO_SIZE) {
546 		/*
547 		 * We do not support isochronous transfers at this
548 		 * time.
549 		 */
550 		dev_err(&spi->dev,
551 			"%s: packet-size of %u too big (limit is %u bytes)",
552 			__func__, max_packet, MAX3421_FIFO_SIZE);
553 		max3421_hcd->urb_done = -EMSGSIZE;
554 		return -EMSGSIZE;
555 	}
556 	max3421_hcd->curr_len = min((urb->transfer_buffer_length -
557 				     urb->actual_length), max_packet);
558 
559 	spi_wr_buf(hcd, MAX3421_REG_SNDFIFO, src, max3421_hcd->curr_len);
560 	spi_wr8(hcd, MAX3421_REG_SNDBC, max3421_hcd->curr_len);
561 	return MAX3421_HXFR_BULK_OUT(epnum);
562 }
563 
564 /*
565  * Issue the next host-transfer command.
566  * Caller must NOT hold HCD spinlock.
567  */
568 static void
569 max3421_next_transfer(struct usb_hcd *hcd, int fast_retransmit)
570 {
571 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
572 	struct urb *urb = max3421_hcd->curr_urb;
573 	struct max3421_ep *max3421_ep;
574 	int cmd = -EINVAL;
575 
576 	if (!urb)
577 		return;	/* nothing to do */
578 
579 	max3421_ep = urb->ep->hcpriv;
580 
581 	switch (max3421_ep->pkt_state) {
582 	case PKT_STATE_SETUP:
583 		cmd = max3421_ctrl_setup(hcd, urb);
584 		break;
585 
586 	case PKT_STATE_TRANSFER:
587 		if (usb_urb_dir_in(urb))
588 			cmd = max3421_transfer_in(hcd, urb);
589 		else
590 			cmd = max3421_transfer_out(hcd, urb, fast_retransmit);
591 		break;
592 
593 	case PKT_STATE_TERMINATE:
594 		/*
595 		 * IN transfers are terminated with HS_OUT token,
596 		 * OUT transfers with HS_IN:
597 		 */
598 		if (usb_urb_dir_in(urb))
599 			cmd = MAX3421_HXFR_HS_OUT;
600 		else
601 			cmd = MAX3421_HXFR_HS_IN;
602 		break;
603 	}
604 
605 	if (cmd < 0)
606 		return;
607 
608 	/* issue the command and wait for host-xfer-done interrupt: */
609 
610 	spi_wr8(hcd, MAX3421_REG_HXFR, cmd);
611 	max3421_hcd->hien |= BIT(MAX3421_HI_HXFRDN_BIT);
612 }
613 
614 /*
615  * Find the next URB to process and start its execution.
616  *
617  * At this time, we do not anticipate ever connecting a USB hub to the
618  * MAX3421 chip, so at most USB device can be connected and we can use
619  * a simplistic scheduler: at the start of a frame, schedule all
620  * periodic transfers.  Once that is done, use the remainder of the
621  * frame to process non-periodic (bulk & control) transfers.
622  *
623  * Preconditions:
624  * o Caller must NOT hold HCD spinlock.
625  * o max3421_hcd->curr_urb MUST BE NULL.
626  * o MAX3421E chip must be idle.
627  */
628 static int
629 max3421_select_and_start_urb(struct usb_hcd *hcd)
630 {
631 	struct spi_device *spi = to_spi_device(hcd->self.controller);
632 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
633 	struct urb *urb, *curr_urb = NULL;
634 	struct max3421_ep *max3421_ep;
635 	int epnum;
636 	struct usb_host_endpoint *ep;
637 	struct list_head *pos;
638 	unsigned long flags;
639 
640 	spin_lock_irqsave(&max3421_hcd->lock, flags);
641 
642 	for (;
643 	     max3421_hcd->sched_pass < SCHED_PASS_DONE;
644 	     ++max3421_hcd->sched_pass)
645 		list_for_each(pos, &max3421_hcd->ep_list) {
646 			urb = NULL;
647 			max3421_ep = container_of(pos, struct max3421_ep,
648 						  ep_list);
649 			ep = max3421_ep->ep;
650 
651 			switch (usb_endpoint_type(&ep->desc)) {
652 			case USB_ENDPOINT_XFER_ISOC:
653 			case USB_ENDPOINT_XFER_INT:
654 				if (max3421_hcd->sched_pass !=
655 				    SCHED_PASS_PERIODIC)
656 					continue;
657 				break;
658 
659 			case USB_ENDPOINT_XFER_CONTROL:
660 			case USB_ENDPOINT_XFER_BULK:
661 				if (max3421_hcd->sched_pass !=
662 				    SCHED_PASS_NON_PERIODIC)
663 					continue;
664 				break;
665 			}
666 
667 			if (list_empty(&ep->urb_list))
668 				continue;	/* nothing to do */
669 			urb = list_first_entry(&ep->urb_list, struct urb,
670 					       urb_list);
671 			if (urb->unlinked) {
672 				dev_dbg(&spi->dev, "%s: URB %p unlinked=%d",
673 					__func__, urb, urb->unlinked);
674 				max3421_hcd->curr_urb = urb;
675 				max3421_hcd->urb_done = 1;
676 				spin_unlock_irqrestore(&max3421_hcd->lock,
677 						       flags);
678 				return 1;
679 			}
680 
681 			switch (usb_endpoint_type(&ep->desc)) {
682 			case USB_ENDPOINT_XFER_CONTROL:
683 				/*
684 				 * Allow one control transaction per
685 				 * frame per endpoint:
686 				 */
687 				if (frame_diff(max3421_ep->last_active,
688 					       max3421_hcd->frame_number) == 0)
689 					continue;
690 				break;
691 
692 			case USB_ENDPOINT_XFER_BULK:
693 				if (max3421_ep->retransmit
694 				    && (frame_diff(max3421_ep->last_active,
695 						   max3421_hcd->frame_number)
696 					== 0))
697 					/*
698 					 * We already tried this EP
699 					 * during this frame and got a
700 					 * NAK or error; wait for next frame
701 					 */
702 					continue;
703 				break;
704 
705 			case USB_ENDPOINT_XFER_ISOC:
706 			case USB_ENDPOINT_XFER_INT:
707 				if (frame_diff(max3421_hcd->frame_number,
708 					       max3421_ep->last_active)
709 				    < urb->interval)
710 					/*
711 					 * We already processed this
712 					 * end-point in the current
713 					 * frame
714 					 */
715 					continue;
716 				break;
717 			}
718 
719 			/* move current ep to tail: */
720 			list_move_tail(pos, &max3421_hcd->ep_list);
721 			curr_urb = urb;
722 			goto done;
723 		}
724 done:
725 	if (!curr_urb) {
726 		spin_unlock_irqrestore(&max3421_hcd->lock, flags);
727 		return 0;
728 	}
729 
730 	urb = max3421_hcd->curr_urb = curr_urb;
731 	epnum = usb_endpoint_num(&urb->ep->desc);
732 	if (max3421_ep->retransmit)
733 		/* restart (part of) a USB transaction: */
734 		max3421_ep->retransmit = 0;
735 	else {
736 		/* start USB transaction: */
737 		if (usb_endpoint_xfer_control(&ep->desc)) {
738 			/*
739 			 * See USB 2.0 spec section 8.6.1
740 			 * Initialization via SETUP Token:
741 			 */
742 			usb_settoggle(urb->dev, epnum, 0, 1);
743 			usb_settoggle(urb->dev, epnum, 1, 1);
744 			max3421_ep->pkt_state = PKT_STATE_SETUP;
745 		} else
746 			max3421_ep->pkt_state = PKT_STATE_TRANSFER;
747 	}
748 
749 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
750 
751 	max3421_ep->last_active = max3421_hcd->frame_number;
752 	max3421_set_address(hcd, urb->dev, epnum);
753 	max3421_set_speed(hcd, urb->dev);
754 	max3421_next_transfer(hcd, 0);
755 	return 1;
756 }
757 
758 /*
759  * Check all endpoints for URBs that got unlinked.
760  *
761  * Caller must NOT hold HCD spinlock.
762  */
763 static int
764 max3421_check_unlink(struct usb_hcd *hcd)
765 {
766 	struct spi_device *spi = to_spi_device(hcd->self.controller);
767 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
768 	struct max3421_ep *max3421_ep;
769 	struct usb_host_endpoint *ep;
770 	struct urb *urb, *next;
771 	unsigned long flags;
772 	int retval = 0;
773 
774 	spin_lock_irqsave(&max3421_hcd->lock, flags);
775 	list_for_each_entry(max3421_ep, &max3421_hcd->ep_list, ep_list) {
776 		ep = max3421_ep->ep;
777 		list_for_each_entry_safe(urb, next, &ep->urb_list, urb_list) {
778 			if (urb->unlinked) {
779 				retval = 1;
780 				dev_dbg(&spi->dev, "%s: URB %p unlinked=%d",
781 					__func__, urb, urb->unlinked);
782 				if (urb == max3421_hcd->curr_urb) {
783 					max3421_hcd->urb_done = 1;
784 					max3421_hcd->hien &= ~(BIT(MAX3421_HI_HXFRDN_BIT) |
785 							       BIT(MAX3421_HI_RCVDAV_BIT));
786 				} else {
787 					usb_hcd_unlink_urb_from_ep(hcd, urb);
788 					spin_unlock_irqrestore(&max3421_hcd->lock,
789 							       flags);
790 					usb_hcd_giveback_urb(hcd, urb, 0);
791 					spin_lock_irqsave(&max3421_hcd->lock, flags);
792 				}
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 		max3421_next_transfer(hcd, 1);
928 		switch_sndfifo = 0;
929 		break;
930 	}
931 	if (switch_sndfifo)
932 		spi_wr8(hcd, MAX3421_REG_SNDBC, 0);
933 }
934 
935 /*
936  * Caller must NOT hold HCD spinlock.
937  */
938 static int
939 max3421_transfer_in_done(struct usb_hcd *hcd, struct urb *urb)
940 {
941 	struct spi_device *spi = to_spi_device(hcd->self.controller);
942 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
943 	u32 max_packet;
944 
945 	if (urb->actual_length >= urb->transfer_buffer_length)
946 		return 1;	/* read is complete, so we're done */
947 
948 	/*
949 	 * USB 2.0 Section 5.3.2 Pipes: packets must be full size
950 	 * except for last one.
951 	 */
952 	max_packet = usb_maxpacket(urb->dev, urb->pipe);
953 	if (max_packet > MAX3421_FIFO_SIZE) {
954 		/*
955 		 * We do not support isochronous transfers at this
956 		 * time...
957 		 */
958 		dev_err(&spi->dev,
959 			"%s: packet-size of %u too big (limit is %u bytes)",
960 			__func__, max_packet, MAX3421_FIFO_SIZE);
961 		return -EINVAL;
962 	}
963 
964 	if (max3421_hcd->curr_len < max_packet) {
965 		if (urb->transfer_flags & URB_SHORT_NOT_OK) {
966 			/*
967 			 * remaining > 0 and received an
968 			 * unexpected partial packet ->
969 			 * error
970 			 */
971 			return -EREMOTEIO;
972 		} else
973 			/* short read, but it's OK */
974 			return 1;
975 	}
976 	return 0;	/* not done */
977 }
978 
979 /*
980  * Caller must NOT hold HCD spinlock.
981  */
982 static int
983 max3421_transfer_out_done(struct usb_hcd *hcd, struct urb *urb)
984 {
985 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
986 
987 	urb->actual_length += max3421_hcd->curr_len;
988 	if (urb->actual_length < urb->transfer_buffer_length)
989 		return 0;
990 	if (urb->transfer_flags & URB_ZERO_PACKET) {
991 		/*
992 		 * Some hardware needs a zero-size packet at the end
993 		 * of a bulk-out transfer if the last transfer was a
994 		 * full-sized packet (i.e., such hardware use <
995 		 * max_packet as an indicator that the end of the
996 		 * packet has been reached).
997 		 */
998 		u32 max_packet = usb_maxpacket(urb->dev, urb->pipe);
999 
1000 		if (max3421_hcd->curr_len == max_packet)
1001 			return 0;
1002 	}
1003 	return 1;
1004 }
1005 
1006 /*
1007  * Caller must NOT hold HCD spinlock.
1008  */
1009 static void
1010 max3421_host_transfer_done(struct usb_hcd *hcd)
1011 {
1012 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1013 	struct urb *urb = max3421_hcd->curr_urb;
1014 	struct max3421_ep *max3421_ep;
1015 	u8 result_code, hrsl;
1016 	int urb_done = 0;
1017 
1018 	max3421_hcd->hien &= ~(BIT(MAX3421_HI_HXFRDN_BIT) |
1019 			       BIT(MAX3421_HI_RCVDAV_BIT));
1020 
1021 	hrsl = spi_rd8(hcd, MAX3421_REG_HRSL);
1022 	result_code = hrsl & MAX3421_HRSL_RESULT_MASK;
1023 
1024 #ifdef DEBUG
1025 	++max3421_hcd->err_stat[result_code];
1026 #endif
1027 
1028 	max3421_ep = urb->ep->hcpriv;
1029 
1030 	if (unlikely(result_code != MAX3421_HRSL_OK)) {
1031 		max3421_handle_error(hcd, hrsl);
1032 		return;
1033 	}
1034 
1035 	max3421_ep->naks = 0;
1036 	max3421_ep->retries = 0;
1037 	switch (max3421_ep->pkt_state) {
1038 
1039 	case PKT_STATE_SETUP:
1040 		if (urb->transfer_buffer_length > 0)
1041 			max3421_ep->pkt_state = PKT_STATE_TRANSFER;
1042 		else
1043 			max3421_ep->pkt_state = PKT_STATE_TERMINATE;
1044 		break;
1045 
1046 	case PKT_STATE_TRANSFER:
1047 		if (usb_urb_dir_in(urb))
1048 			urb_done = max3421_transfer_in_done(hcd, urb);
1049 		else
1050 			urb_done = max3421_transfer_out_done(hcd, urb);
1051 		if (urb_done > 0 && usb_pipetype(urb->pipe) == PIPE_CONTROL) {
1052 			/*
1053 			 * We aren't really done - we still need to
1054 			 * terminate the control transfer:
1055 			 */
1056 			max3421_hcd->urb_done = urb_done = 0;
1057 			max3421_ep->pkt_state = PKT_STATE_TERMINATE;
1058 		}
1059 		break;
1060 
1061 	case PKT_STATE_TERMINATE:
1062 		urb_done = 1;
1063 		break;
1064 	}
1065 
1066 	if (urb_done)
1067 		max3421_hcd->urb_done = urb_done;
1068 	else
1069 		max3421_next_transfer(hcd, 0);
1070 }
1071 
1072 /*
1073  * Caller must NOT hold HCD spinlock.
1074  */
1075 static void
1076 max3421_detect_conn(struct usb_hcd *hcd)
1077 {
1078 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1079 	unsigned int jk, have_conn = 0;
1080 	u32 old_port_status, chg;
1081 	unsigned long flags;
1082 	u8 hrsl, mode;
1083 
1084 	hrsl = spi_rd8(hcd, MAX3421_REG_HRSL);
1085 
1086 	jk = ((((hrsl >> MAX3421_HRSL_JSTATUS_BIT) & 1) << 0) |
1087 	      (((hrsl >> MAX3421_HRSL_KSTATUS_BIT) & 1) << 1));
1088 
1089 	mode = max3421_hcd->mode;
1090 
1091 	switch (jk) {
1092 	case 0x0: /* SE0: disconnect */
1093 		/*
1094 		 * Turn off SOFKAENAB bit to avoid getting interrupt
1095 		 * every milli-second:
1096 		 */
1097 		mode &= ~BIT(MAX3421_MODE_SOFKAENAB_BIT);
1098 		break;
1099 
1100 	case 0x1: /* J=0,K=1: low-speed (in full-speed or vice versa) */
1101 	case 0x2: /* J=1,K=0: full-speed (in full-speed or vice versa) */
1102 		if (jk == 0x2)
1103 			/* need to switch to the other speed: */
1104 			mode ^= BIT(MAX3421_MODE_LOWSPEED_BIT);
1105 		/* turn on SOFKAENAB bit: */
1106 		mode |= BIT(MAX3421_MODE_SOFKAENAB_BIT);
1107 		have_conn = 1;
1108 		break;
1109 
1110 	case 0x3: /* illegal */
1111 		break;
1112 	}
1113 
1114 	max3421_hcd->mode = mode;
1115 	spi_wr8(hcd, MAX3421_REG_MODE, max3421_hcd->mode);
1116 
1117 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1118 	old_port_status = max3421_hcd->port_status;
1119 	if (have_conn)
1120 		max3421_hcd->port_status |=  USB_PORT_STAT_CONNECTION;
1121 	else
1122 		max3421_hcd->port_status &= ~USB_PORT_STAT_CONNECTION;
1123 	if (mode & BIT(MAX3421_MODE_LOWSPEED_BIT))
1124 		max3421_hcd->port_status |=  USB_PORT_STAT_LOW_SPEED;
1125 	else
1126 		max3421_hcd->port_status &= ~USB_PORT_STAT_LOW_SPEED;
1127 	chg = (old_port_status ^ max3421_hcd->port_status);
1128 	max3421_hcd->port_status |= chg << 16;
1129 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1130 }
1131 
1132 static irqreturn_t
1133 max3421_irq_handler(int irq, void *dev_id)
1134 {
1135 	struct usb_hcd *hcd = dev_id;
1136 	struct spi_device *spi = to_spi_device(hcd->self.controller);
1137 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1138 
1139 	if (max3421_hcd->spi_thread)
1140 		wake_up_process(max3421_hcd->spi_thread);
1141 	if (!test_and_set_bit(ENABLE_IRQ, &max3421_hcd->todo))
1142 		disable_irq_nosync(spi->irq);
1143 	return IRQ_HANDLED;
1144 }
1145 
1146 #ifdef DEBUG
1147 
1148 static void
1149 dump_eps(struct usb_hcd *hcd)
1150 {
1151 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1152 	struct max3421_ep *max3421_ep;
1153 	struct usb_host_endpoint *ep;
1154 	char ubuf[512], *dp, *end;
1155 	unsigned long flags;
1156 	struct urb *urb;
1157 	int epnum, ret;
1158 
1159 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1160 	list_for_each_entry(max3421_ep, &max3421_hcd->ep_list, ep_list) {
1161 		ep = max3421_ep->ep;
1162 
1163 		dp = ubuf;
1164 		end = dp + sizeof(ubuf);
1165 		*dp = '\0';
1166 		list_for_each_entry(urb, &ep->urb_list, urb_list) {
1167 			ret = snprintf(dp, end - dp, " %p(%d.%s %d/%d)", urb,
1168 				       usb_pipetype(urb->pipe),
1169 				       usb_urb_dir_in(urb) ? "IN" : "OUT",
1170 				       urb->actual_length,
1171 				       urb->transfer_buffer_length);
1172 			if (ret < 0 || ret >= end - dp)
1173 				break;	/* error or buffer full */
1174 			dp += ret;
1175 		}
1176 
1177 		epnum = usb_endpoint_num(&ep->desc);
1178 		pr_info("EP%0u %u lst %04u rtr %u nak %6u rxmt %u: %s\n",
1179 			epnum, max3421_ep->pkt_state, max3421_ep->last_active,
1180 			max3421_ep->retries, max3421_ep->naks,
1181 			max3421_ep->retransmit, ubuf);
1182 	}
1183 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1184 }
1185 
1186 #endif /* DEBUG */
1187 
1188 /* Return zero if no work was performed, 1 otherwise.  */
1189 static int
1190 max3421_handle_irqs(struct usb_hcd *hcd)
1191 {
1192 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1193 	u32 chg, old_port_status;
1194 	unsigned long flags;
1195 	u8 hirq;
1196 
1197 	/*
1198 	 * Read and ack pending interrupts (CPU must never
1199 	 * clear SNDBAV directly and RCVDAV must be cleared by
1200 	 * max3421_recv_data_available()!):
1201 	 */
1202 	hirq = spi_rd8(hcd, MAX3421_REG_HIRQ);
1203 	hirq &= max3421_hcd->hien;
1204 	if (!hirq)
1205 		return 0;
1206 
1207 	spi_wr8(hcd, MAX3421_REG_HIRQ,
1208 		hirq & ~(BIT(MAX3421_HI_SNDBAV_BIT) |
1209 			 BIT(MAX3421_HI_RCVDAV_BIT)));
1210 
1211 	if (hirq & BIT(MAX3421_HI_FRAME_BIT)) {
1212 		max3421_hcd->frame_number = ((max3421_hcd->frame_number + 1)
1213 					     & USB_MAX_FRAME_NUMBER);
1214 		max3421_hcd->sched_pass = SCHED_PASS_PERIODIC;
1215 	}
1216 
1217 	if (hirq & BIT(MAX3421_HI_RCVDAV_BIT))
1218 		max3421_recv_data_available(hcd);
1219 
1220 	if (hirq & BIT(MAX3421_HI_HXFRDN_BIT))
1221 		max3421_host_transfer_done(hcd);
1222 
1223 	if (hirq & BIT(MAX3421_HI_CONDET_BIT))
1224 		max3421_detect_conn(hcd);
1225 
1226 	/*
1227 	 * Now process interrupts that may affect HCD state
1228 	 * other than the end-points:
1229 	 */
1230 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1231 
1232 	old_port_status = max3421_hcd->port_status;
1233 	if (hirq & BIT(MAX3421_HI_BUSEVENT_BIT)) {
1234 		if (max3421_hcd->port_status & USB_PORT_STAT_RESET) {
1235 			/* BUSEVENT due to completion of Bus Reset */
1236 			max3421_hcd->port_status &= ~USB_PORT_STAT_RESET;
1237 			max3421_hcd->port_status |=  USB_PORT_STAT_ENABLE;
1238 		} else {
1239 			/* BUSEVENT due to completion of Bus Resume */
1240 			pr_info("%s: BUSEVENT Bus Resume Done\n", __func__);
1241 		}
1242 	}
1243 	if (hirq & BIT(MAX3421_HI_RWU_BIT))
1244 		pr_info("%s: RWU\n", __func__);
1245 	if (hirq & BIT(MAX3421_HI_SUSDN_BIT))
1246 		pr_info("%s: SUSDN\n", __func__);
1247 
1248 	chg = (old_port_status ^ max3421_hcd->port_status);
1249 	max3421_hcd->port_status |= chg << 16;
1250 
1251 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1252 
1253 #ifdef DEBUG
1254 	{
1255 		static unsigned long last_time;
1256 		char sbuf[16 * 16], *dp, *end;
1257 		int i;
1258 
1259 		if (time_after(jiffies, last_time + 5*HZ)) {
1260 			dp = sbuf;
1261 			end = sbuf + sizeof(sbuf);
1262 			*dp = '\0';
1263 			for (i = 0; i < 16; ++i) {
1264 				int ret = snprintf(dp, end - dp, " %lu",
1265 						   max3421_hcd->err_stat[i]);
1266 				if (ret < 0 || ret >= end - dp)
1267 					break;	/* error or buffer full */
1268 				dp += ret;
1269 			}
1270 			pr_info("%s: hrsl_stats %s\n", __func__, sbuf);
1271 			memset(max3421_hcd->err_stat, 0,
1272 			       sizeof(max3421_hcd->err_stat));
1273 			last_time = jiffies;
1274 
1275 			dump_eps(hcd);
1276 		}
1277 	}
1278 #endif
1279 	return 1;
1280 }
1281 
1282 static int
1283 max3421_reset_hcd(struct usb_hcd *hcd)
1284 {
1285 	struct spi_device *spi = to_spi_device(hcd->self.controller);
1286 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1287 	int timeout;
1288 
1289 	/* perform a chip reset and wait for OSCIRQ signal to appear: */
1290 	spi_wr8(hcd, MAX3421_REG_USBCTL, BIT(MAX3421_USBCTL_CHIPRES_BIT));
1291 	/* clear reset: */
1292 	spi_wr8(hcd, MAX3421_REG_USBCTL, 0);
1293 	timeout = 1000;
1294 	while (1) {
1295 		if (spi_rd8(hcd, MAX3421_REG_USBIRQ)
1296 		    & BIT(MAX3421_USBIRQ_OSCOKIRQ_BIT))
1297 			break;
1298 		if (--timeout < 0) {
1299 			dev_err(&spi->dev,
1300 				"timed out waiting for oscillator OK signal");
1301 			return 1;
1302 		}
1303 		cond_resched();
1304 	}
1305 
1306 	/*
1307 	 * Turn on host mode, automatic generation of SOF packets, and
1308 	 * enable pull-down registers on DM/DP:
1309 	 */
1310 	max3421_hcd->mode = (BIT(MAX3421_MODE_HOST_BIT) |
1311 			     BIT(MAX3421_MODE_SOFKAENAB_BIT) |
1312 			     BIT(MAX3421_MODE_DMPULLDN_BIT) |
1313 			     BIT(MAX3421_MODE_DPPULLDN_BIT));
1314 	spi_wr8(hcd, MAX3421_REG_MODE, max3421_hcd->mode);
1315 
1316 	/* reset frame-number: */
1317 	max3421_hcd->frame_number = USB_MAX_FRAME_NUMBER;
1318 	spi_wr8(hcd, MAX3421_REG_HCTL, BIT(MAX3421_HCTL_FRMRST_BIT));
1319 
1320 	/* sample the state of the D+ and D- lines */
1321 	spi_wr8(hcd, MAX3421_REG_HCTL, BIT(MAX3421_HCTL_SAMPLEBUS_BIT));
1322 	max3421_detect_conn(hcd);
1323 
1324 	/* enable frame, connection-detected, and bus-event interrupts: */
1325 	max3421_hcd->hien = (BIT(MAX3421_HI_FRAME_BIT) |
1326 			     BIT(MAX3421_HI_CONDET_BIT) |
1327 			     BIT(MAX3421_HI_BUSEVENT_BIT));
1328 	spi_wr8(hcd, MAX3421_REG_HIEN, max3421_hcd->hien);
1329 
1330 	/* enable interrupts: */
1331 	spi_wr8(hcd, MAX3421_REG_CPUCTL, BIT(MAX3421_CPUCTL_IE_BIT));
1332 	return 1;
1333 }
1334 
1335 static int
1336 max3421_urb_done(struct usb_hcd *hcd)
1337 {
1338 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1339 	unsigned long flags;
1340 	struct urb *urb;
1341 	int status;
1342 
1343 	status = max3421_hcd->urb_done;
1344 	max3421_hcd->urb_done = 0;
1345 	if (status > 0)
1346 		status = 0;
1347 	urb = max3421_hcd->curr_urb;
1348 	if (urb) {
1349 		/* save the old end-points toggles: */
1350 		u8 hrsl = spi_rd8(hcd, MAX3421_REG_HRSL);
1351 		int rcvtog = (hrsl >> MAX3421_HRSL_RCVTOGRD_BIT) & 1;
1352 		int sndtog = (hrsl >> MAX3421_HRSL_SNDTOGRD_BIT) & 1;
1353 		int epnum = usb_endpoint_num(&urb->ep->desc);
1354 
1355 		/* no locking: HCD (i.e., we) own toggles, don't we? */
1356 		usb_settoggle(urb->dev, epnum, 0, rcvtog);
1357 		usb_settoggle(urb->dev, epnum, 1, sndtog);
1358 
1359 		max3421_hcd->curr_urb = NULL;
1360 		spin_lock_irqsave(&max3421_hcd->lock, flags);
1361 		usb_hcd_unlink_urb_from_ep(hcd, urb);
1362 		spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1363 
1364 		/* must be called without the HCD spinlock: */
1365 		usb_hcd_giveback_urb(hcd, urb, status);
1366 	}
1367 	return 1;
1368 }
1369 
1370 static int
1371 max3421_spi_thread(void *dev_id)
1372 {
1373 	struct usb_hcd *hcd = dev_id;
1374 	struct spi_device *spi = to_spi_device(hcd->self.controller);
1375 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1376 	int i, i_worked = 1;
1377 
1378 	/* set full-duplex SPI mode, low-active interrupt pin: */
1379 	spi_wr8(hcd, MAX3421_REG_PINCTL,
1380 		(BIT(MAX3421_PINCTL_FDUPSPI_BIT) |	/* full-duplex */
1381 		 BIT(MAX3421_PINCTL_INTLEVEL_BIT)));	/* low-active irq */
1382 
1383 	while (!kthread_should_stop()) {
1384 		max3421_hcd->rev = spi_rd8(hcd, MAX3421_REG_REVISION);
1385 		if (max3421_hcd->rev == 0x12 || max3421_hcd->rev == 0x13)
1386 			break;
1387 		dev_err(&spi->dev, "bad rev 0x%02x", max3421_hcd->rev);
1388 		msleep(10000);
1389 	}
1390 	dev_info(&spi->dev, "rev 0x%x, SPI clk %dHz, bpw %u, irq %d\n",
1391 		 max3421_hcd->rev, spi->max_speed_hz, spi->bits_per_word,
1392 		 spi->irq);
1393 
1394 	while (!kthread_should_stop()) {
1395 		if (!i_worked) {
1396 			/*
1397 			 * We'll be waiting for wakeups from the hard
1398 			 * interrupt handler, so now is a good time to
1399 			 * sync our hien with the chip:
1400 			 */
1401 			spi_wr8(hcd, MAX3421_REG_HIEN, max3421_hcd->hien);
1402 
1403 			set_current_state(TASK_INTERRUPTIBLE);
1404 			if (test_and_clear_bit(ENABLE_IRQ, &max3421_hcd->todo))
1405 				enable_irq(spi->irq);
1406 			schedule();
1407 			__set_current_state(TASK_RUNNING);
1408 		}
1409 
1410 		i_worked = 0;
1411 
1412 		if (max3421_hcd->urb_done)
1413 			i_worked |= max3421_urb_done(hcd);
1414 		else if (max3421_handle_irqs(hcd))
1415 			i_worked = 1;
1416 		else if (!max3421_hcd->curr_urb)
1417 			i_worked |= max3421_select_and_start_urb(hcd);
1418 
1419 		if (test_and_clear_bit(RESET_HCD, &max3421_hcd->todo))
1420 			/* reset the HCD: */
1421 			i_worked |= max3421_reset_hcd(hcd);
1422 		if (test_and_clear_bit(RESET_PORT, &max3421_hcd->todo)) {
1423 			/* perform a USB bus reset: */
1424 			spi_wr8(hcd, MAX3421_REG_HCTL,
1425 				BIT(MAX3421_HCTL_BUSRST_BIT));
1426 			i_worked = 1;
1427 		}
1428 		if (test_and_clear_bit(CHECK_UNLINK, &max3421_hcd->todo))
1429 			i_worked |= max3421_check_unlink(hcd);
1430 		if (test_and_clear_bit(IOPIN_UPDATE, &max3421_hcd->todo)) {
1431 			/*
1432 			 * IOPINS1/IOPINS2 do not auto-increment, so we can't
1433 			 * use spi_wr_buf().
1434 			 */
1435 			for (i = 0; i < ARRAY_SIZE(max3421_hcd->iopins); ++i) {
1436 				u8 val = spi_rd8(hcd, MAX3421_REG_IOPINS1 + i);
1437 
1438 				val = ((val & 0xf0) |
1439 				       (max3421_hcd->iopins[i] & 0x0f));
1440 				spi_wr8(hcd, MAX3421_REG_IOPINS1 + i, val);
1441 				max3421_hcd->iopins[i] = val;
1442 			}
1443 			i_worked = 1;
1444 		}
1445 	}
1446 	set_current_state(TASK_RUNNING);
1447 	dev_info(&spi->dev, "SPI thread exiting");
1448 	return 0;
1449 }
1450 
1451 static int
1452 max3421_reset_port(struct usb_hcd *hcd)
1453 {
1454 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1455 
1456 	max3421_hcd->port_status &= ~(USB_PORT_STAT_ENABLE |
1457 				      USB_PORT_STAT_LOW_SPEED);
1458 	max3421_hcd->port_status |= USB_PORT_STAT_RESET;
1459 	set_bit(RESET_PORT, &max3421_hcd->todo);
1460 	wake_up_process(max3421_hcd->spi_thread);
1461 	return 0;
1462 }
1463 
1464 static int
1465 max3421_reset(struct usb_hcd *hcd)
1466 {
1467 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1468 
1469 	hcd->self.sg_tablesize = 0;
1470 	hcd->speed = HCD_USB2;
1471 	hcd->self.root_hub->speed = USB_SPEED_FULL;
1472 	set_bit(RESET_HCD, &max3421_hcd->todo);
1473 	wake_up_process(max3421_hcd->spi_thread);
1474 	return 0;
1475 }
1476 
1477 static int
1478 max3421_start(struct usb_hcd *hcd)
1479 {
1480 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1481 
1482 	spin_lock_init(&max3421_hcd->lock);
1483 	max3421_hcd->rh_state = MAX3421_RH_RUNNING;
1484 
1485 	INIT_LIST_HEAD(&max3421_hcd->ep_list);
1486 
1487 	hcd->power_budget = POWER_BUDGET;
1488 	hcd->state = HC_STATE_RUNNING;
1489 	hcd->uses_new_polling = 1;
1490 	return 0;
1491 }
1492 
1493 static void
1494 max3421_stop(struct usb_hcd *hcd)
1495 {
1496 }
1497 
1498 static int
1499 max3421_urb_enqueue(struct usb_hcd *hcd, struct urb *urb, gfp_t mem_flags)
1500 {
1501 	struct spi_device *spi = to_spi_device(hcd->self.controller);
1502 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1503 	struct max3421_ep *max3421_ep;
1504 	unsigned long flags;
1505 	int retval;
1506 
1507 	switch (usb_pipetype(urb->pipe)) {
1508 	case PIPE_INTERRUPT:
1509 	case PIPE_ISOCHRONOUS:
1510 		if (urb->interval < 0) {
1511 			dev_err(&spi->dev,
1512 			  "%s: interval=%d for intr-/iso-pipe; expected > 0\n",
1513 				__func__, urb->interval);
1514 			return -EINVAL;
1515 		}
1516 		break;
1517 	default:
1518 		break;
1519 	}
1520 
1521 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1522 
1523 	max3421_ep = urb->ep->hcpriv;
1524 	if (!max3421_ep) {
1525 		/* gets freed in max3421_endpoint_disable: */
1526 		max3421_ep = kzalloc(sizeof(struct max3421_ep), GFP_ATOMIC);
1527 		if (!max3421_ep) {
1528 			retval = -ENOMEM;
1529 			goto out;
1530 		}
1531 		max3421_ep->ep = urb->ep;
1532 		max3421_ep->last_active = max3421_hcd->frame_number;
1533 		urb->ep->hcpriv = max3421_ep;
1534 
1535 		list_add_tail(&max3421_ep->ep_list, &max3421_hcd->ep_list);
1536 	}
1537 
1538 	retval = usb_hcd_link_urb_to_ep(hcd, urb);
1539 	if (retval == 0) {
1540 		/* Since we added to the queue, restart scheduling: */
1541 		max3421_hcd->sched_pass = SCHED_PASS_PERIODIC;
1542 		wake_up_process(max3421_hcd->spi_thread);
1543 	}
1544 
1545 out:
1546 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1547 	return retval;
1548 }
1549 
1550 static int
1551 max3421_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
1552 {
1553 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1554 	unsigned long flags;
1555 	int retval;
1556 
1557 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1558 
1559 	/*
1560 	 * This will set urb->unlinked which in turn causes the entry
1561 	 * to be dropped at the next opportunity.
1562 	 */
1563 	retval = usb_hcd_check_unlink_urb(hcd, urb, status);
1564 	if (retval == 0) {
1565 		set_bit(CHECK_UNLINK, &max3421_hcd->todo);
1566 		wake_up_process(max3421_hcd->spi_thread);
1567 	}
1568 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1569 	return retval;
1570 }
1571 
1572 static void
1573 max3421_endpoint_disable(struct usb_hcd *hcd, struct usb_host_endpoint *ep)
1574 {
1575 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1576 	unsigned long flags;
1577 
1578 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1579 
1580 	if (ep->hcpriv) {
1581 		struct max3421_ep *max3421_ep = ep->hcpriv;
1582 
1583 		/* remove myself from the ep_list: */
1584 		if (!list_empty(&max3421_ep->ep_list))
1585 			list_del(&max3421_ep->ep_list);
1586 		kfree(max3421_ep);
1587 		ep->hcpriv = NULL;
1588 	}
1589 
1590 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1591 }
1592 
1593 static int
1594 max3421_get_frame_number(struct usb_hcd *hcd)
1595 {
1596 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1597 	return max3421_hcd->frame_number;
1598 }
1599 
1600 /*
1601  * Should return a non-zero value when any port is undergoing a resume
1602  * transition while the root hub is suspended.
1603  */
1604 static int
1605 max3421_hub_status_data(struct usb_hcd *hcd, char *buf)
1606 {
1607 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1608 	unsigned long flags;
1609 	int retval = 0;
1610 
1611 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1612 	if (!HCD_HW_ACCESSIBLE(hcd))
1613 		goto done;
1614 
1615 	*buf = 0;
1616 	if ((max3421_hcd->port_status & PORT_C_MASK) != 0) {
1617 		*buf = (1 << 1); /* a hub over-current condition exists */
1618 		dev_dbg(hcd->self.controller,
1619 			"port status 0x%08x has changes\n",
1620 			max3421_hcd->port_status);
1621 		retval = 1;
1622 		if (max3421_hcd->rh_state == MAX3421_RH_SUSPENDED)
1623 			usb_hcd_resume_root_hub(hcd);
1624 	}
1625 done:
1626 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1627 	return retval;
1628 }
1629 
1630 static inline void
1631 hub_descriptor(struct usb_hub_descriptor *desc)
1632 {
1633 	memset(desc, 0, sizeof(*desc));
1634 	/*
1635 	 * See Table 11-13: Hub Descriptor in USB 2.0 spec.
1636 	 */
1637 	desc->bDescriptorType = USB_DT_HUB; /* hub descriptor */
1638 	desc->bDescLength = 9;
1639 	desc->wHubCharacteristics = cpu_to_le16(HUB_CHAR_INDV_PORT_LPSM |
1640 						HUB_CHAR_COMMON_OCPM);
1641 	desc->bNbrPorts = 1;
1642 }
1643 
1644 /*
1645  * Set the MAX3421E general-purpose output with number PIN_NUMBER to
1646  * VALUE (0 or 1).  PIN_NUMBER may be in the range from 1-8.  For
1647  * any other value, this function acts as a no-op.
1648  */
1649 static void
1650 max3421_gpout_set_value(struct usb_hcd *hcd, u8 pin_number, u8 value)
1651 {
1652 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1653 	u8 mask, idx;
1654 
1655 	--pin_number;
1656 	if (pin_number >= MAX3421_GPOUT_COUNT)
1657 		return;
1658 
1659 	mask = 1u << (pin_number % 4);
1660 	idx = pin_number / 4;
1661 
1662 	if (value)
1663 		max3421_hcd->iopins[idx] |=  mask;
1664 	else
1665 		max3421_hcd->iopins[idx] &= ~mask;
1666 	set_bit(IOPIN_UPDATE, &max3421_hcd->todo);
1667 	wake_up_process(max3421_hcd->spi_thread);
1668 }
1669 
1670 static int
1671 max3421_hub_control(struct usb_hcd *hcd, u16 type_req, u16 value, u16 index,
1672 		    char *buf, u16 length)
1673 {
1674 	struct spi_device *spi = to_spi_device(hcd->self.controller);
1675 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1676 	struct max3421_hcd_platform_data *pdata;
1677 	unsigned long flags;
1678 	int retval = 0;
1679 
1680 	pdata = spi->dev.platform_data;
1681 
1682 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1683 
1684 	switch (type_req) {
1685 	case ClearHubFeature:
1686 		break;
1687 	case ClearPortFeature:
1688 		switch (value) {
1689 		case USB_PORT_FEAT_SUSPEND:
1690 			break;
1691 		case USB_PORT_FEAT_POWER:
1692 			dev_dbg(hcd->self.controller, "power-off\n");
1693 			max3421_gpout_set_value(hcd, pdata->vbus_gpout,
1694 						!pdata->vbus_active_level);
1695 			fallthrough;
1696 		default:
1697 			max3421_hcd->port_status &= ~(1 << value);
1698 		}
1699 		break;
1700 	case GetHubDescriptor:
1701 		hub_descriptor((struct usb_hub_descriptor *) buf);
1702 		break;
1703 
1704 	case DeviceRequest | USB_REQ_GET_DESCRIPTOR:
1705 	case GetPortErrorCount:
1706 	case SetHubDepth:
1707 		/* USB3 only */
1708 		goto error;
1709 
1710 	case GetHubStatus:
1711 		*(__le32 *) buf = cpu_to_le32(0);
1712 		break;
1713 
1714 	case GetPortStatus:
1715 		if (index != 1) {
1716 			retval = -EPIPE;
1717 			goto error;
1718 		}
1719 		((__le16 *) buf)[0] = cpu_to_le16(max3421_hcd->port_status);
1720 		((__le16 *) buf)[1] =
1721 			cpu_to_le16(max3421_hcd->port_status >> 16);
1722 		break;
1723 
1724 	case SetHubFeature:
1725 		retval = -EPIPE;
1726 		break;
1727 
1728 	case SetPortFeature:
1729 		switch (value) {
1730 		case USB_PORT_FEAT_LINK_STATE:
1731 		case USB_PORT_FEAT_U1_TIMEOUT:
1732 		case USB_PORT_FEAT_U2_TIMEOUT:
1733 		case USB_PORT_FEAT_BH_PORT_RESET:
1734 			goto error;
1735 		case USB_PORT_FEAT_SUSPEND:
1736 			if (max3421_hcd->active)
1737 				max3421_hcd->port_status |=
1738 					USB_PORT_STAT_SUSPEND;
1739 			break;
1740 		case USB_PORT_FEAT_POWER:
1741 			dev_dbg(hcd->self.controller, "power-on\n");
1742 			max3421_hcd->port_status |= USB_PORT_STAT_POWER;
1743 			max3421_gpout_set_value(hcd, pdata->vbus_gpout,
1744 						pdata->vbus_active_level);
1745 			break;
1746 		case USB_PORT_FEAT_RESET:
1747 			max3421_reset_port(hcd);
1748 			fallthrough;
1749 		default:
1750 			if ((max3421_hcd->port_status & USB_PORT_STAT_POWER)
1751 			    != 0)
1752 				max3421_hcd->port_status |= (1 << value);
1753 		}
1754 		break;
1755 
1756 	default:
1757 		dev_dbg(hcd->self.controller,
1758 			"hub control req%04x v%04x i%04x l%d\n",
1759 			type_req, value, index, length);
1760 error:		/* "protocol stall" on error */
1761 		retval = -EPIPE;
1762 	}
1763 
1764 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1765 	return retval;
1766 }
1767 
1768 static int
1769 max3421_bus_suspend(struct usb_hcd *hcd)
1770 {
1771 	return -1;
1772 }
1773 
1774 static int
1775 max3421_bus_resume(struct usb_hcd *hcd)
1776 {
1777 	return -1;
1778 }
1779 
1780 static const struct hc_driver max3421_hcd_desc = {
1781 	.description =		"max3421",
1782 	.product_desc =		DRIVER_DESC,
1783 	.hcd_priv_size =	sizeof(struct max3421_hcd),
1784 	.flags =		HCD_USB11,
1785 	.reset =		max3421_reset,
1786 	.start =		max3421_start,
1787 	.stop =			max3421_stop,
1788 	.get_frame_number =	max3421_get_frame_number,
1789 	.urb_enqueue =		max3421_urb_enqueue,
1790 	.urb_dequeue =		max3421_urb_dequeue,
1791 	.endpoint_disable =	max3421_endpoint_disable,
1792 	.hub_status_data =	max3421_hub_status_data,
1793 	.hub_control =		max3421_hub_control,
1794 	.bus_suspend =		max3421_bus_suspend,
1795 	.bus_resume =		max3421_bus_resume,
1796 };
1797 
1798 static int
1799 max3421_of_vbus_en_pin(struct device *dev, struct max3421_hcd_platform_data *pdata)
1800 {
1801 	int retval;
1802 	uint32_t value[2];
1803 
1804 	if (!pdata)
1805 		return -EINVAL;
1806 
1807 	retval = of_property_read_u32_array(dev->of_node, "maxim,vbus-en-pin", value, 2);
1808 	if (retval) {
1809 		dev_err(dev, "device tree node property 'maxim,vbus-en-pin' is missing\n");
1810 		return retval;
1811 	}
1812 	dev_info(dev, "property 'maxim,vbus-en-pin' value is <%d %d>\n", value[0], value[1]);
1813 
1814 	pdata->vbus_gpout = value[0];
1815 	pdata->vbus_active_level = value[1];
1816 
1817 	return 0;
1818 }
1819 
1820 static int
1821 max3421_probe(struct spi_device *spi)
1822 {
1823 	struct device *dev = &spi->dev;
1824 	struct max3421_hcd *max3421_hcd;
1825 	struct usb_hcd *hcd = NULL;
1826 	struct max3421_hcd_platform_data *pdata = NULL;
1827 	int retval;
1828 
1829 	if (spi_setup(spi) < 0) {
1830 		dev_err(&spi->dev, "Unable to setup SPI bus");
1831 		return -EFAULT;
1832 	}
1833 
1834 	if (!spi->irq) {
1835 		dev_err(dev, "Failed to get SPI IRQ");
1836 		return -EFAULT;
1837 	}
1838 
1839 	if (IS_ENABLED(CONFIG_OF) && dev->of_node) {
1840 		pdata = devm_kzalloc(&spi->dev, sizeof(*pdata), GFP_KERNEL);
1841 		if (!pdata) {
1842 			retval = -ENOMEM;
1843 			goto error;
1844 		}
1845 		retval = max3421_of_vbus_en_pin(dev, pdata);
1846 		if (retval)
1847 			goto error;
1848 
1849 		spi->dev.platform_data = pdata;
1850 	}
1851 
1852 	pdata = spi->dev.platform_data;
1853 	if (!pdata) {
1854 		dev_err(&spi->dev, "driver configuration data is not provided\n");
1855 		retval = -EFAULT;
1856 		goto error;
1857 	}
1858 	if (pdata->vbus_active_level > 1) {
1859 		dev_err(&spi->dev, "vbus active level value %d is out of range (0/1)\n", pdata->vbus_active_level);
1860 		retval = -EINVAL;
1861 		goto error;
1862 	}
1863 	if (pdata->vbus_gpout < 1 || pdata->vbus_gpout > MAX3421_GPOUT_COUNT) {
1864 		dev_err(&spi->dev, "vbus gpout value %d is out of range (1..8)\n", pdata->vbus_gpout);
1865 		retval = -EINVAL;
1866 		goto error;
1867 	}
1868 
1869 	retval = -ENOMEM;
1870 	hcd = usb_create_hcd(&max3421_hcd_desc, &spi->dev,
1871 			     dev_name(&spi->dev));
1872 	if (!hcd) {
1873 		dev_err(&spi->dev, "failed to create HCD structure\n");
1874 		goto error;
1875 	}
1876 	set_bit(HCD_FLAG_POLL_RH, &hcd->flags);
1877 	max3421_hcd = hcd_to_max3421(hcd);
1878 	INIT_LIST_HEAD(&max3421_hcd->ep_list);
1879 	spi_set_drvdata(spi, max3421_hcd);
1880 
1881 	max3421_hcd->tx = kmalloc(sizeof(*max3421_hcd->tx), GFP_KERNEL);
1882 	if (!max3421_hcd->tx)
1883 		goto error;
1884 	max3421_hcd->rx = kmalloc(sizeof(*max3421_hcd->rx), GFP_KERNEL);
1885 	if (!max3421_hcd->rx)
1886 		goto error;
1887 
1888 	max3421_hcd->spi_thread = kthread_run(max3421_spi_thread, hcd,
1889 					      "max3421_spi_thread");
1890 	if (max3421_hcd->spi_thread == ERR_PTR(-ENOMEM)) {
1891 		dev_err(&spi->dev,
1892 			"failed to create SPI thread (out of memory)\n");
1893 		goto error;
1894 	}
1895 
1896 	retval = usb_add_hcd(hcd, 0, 0);
1897 	if (retval) {
1898 		dev_err(&spi->dev, "failed to add HCD\n");
1899 		goto error;
1900 	}
1901 
1902 	retval = request_irq(spi->irq, max3421_irq_handler,
1903 			     IRQF_TRIGGER_LOW, "max3421", hcd);
1904 	if (retval < 0) {
1905 		dev_err(&spi->dev, "failed to request irq %d\n", spi->irq);
1906 		goto error;
1907 	}
1908 	return 0;
1909 
1910 error:
1911 	if (IS_ENABLED(CONFIG_OF) && dev->of_node && pdata) {
1912 		devm_kfree(&spi->dev, pdata);
1913 		spi->dev.platform_data = NULL;
1914 	}
1915 
1916 	if (hcd) {
1917 		kfree(max3421_hcd->tx);
1918 		kfree(max3421_hcd->rx);
1919 		if (max3421_hcd->spi_thread)
1920 			kthread_stop(max3421_hcd->spi_thread);
1921 		usb_put_hcd(hcd);
1922 	}
1923 	return retval;
1924 }
1925 
1926 static void
1927 max3421_remove(struct spi_device *spi)
1928 {
1929 	struct max3421_hcd *max3421_hcd;
1930 	struct usb_hcd *hcd;
1931 	unsigned long flags;
1932 
1933 	max3421_hcd = spi_get_drvdata(spi);
1934 	hcd = max3421_to_hcd(max3421_hcd);
1935 
1936 	usb_remove_hcd(hcd);
1937 
1938 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1939 
1940 	kthread_stop(max3421_hcd->spi_thread);
1941 
1942 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1943 
1944 	free_irq(spi->irq, hcd);
1945 
1946 	usb_put_hcd(hcd);
1947 }
1948 
1949 static const struct of_device_id max3421_of_match_table[] = {
1950 	{ .compatible = "maxim,max3421", },
1951 	{},
1952 };
1953 MODULE_DEVICE_TABLE(of, max3421_of_match_table);
1954 
1955 static struct spi_driver max3421_driver = {
1956 	.probe		= max3421_probe,
1957 	.remove		= max3421_remove,
1958 	.driver		= {
1959 		.name	= "max3421-hcd",
1960 		.of_match_table = max3421_of_match_table,
1961 	},
1962 };
1963 
1964 module_spi_driver(max3421_driver);
1965 
1966 MODULE_DESCRIPTION(DRIVER_DESC);
1967 MODULE_AUTHOR("David Mosberger <davidm@egauge.net>");
1968 MODULE_LICENSE("GPL");
1969