xref: /openbmc/linux/drivers/usb/host/max3421-hcd.c (revision 2f164822)
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 				usb_hcd_unlink_urb_from_ep(hcd, urb);
783 				spin_unlock_irqrestore(&max3421_hcd->lock,
784 						       flags);
785 				usb_hcd_giveback_urb(hcd, urb, 0);
786 				spin_lock_irqsave(&max3421_hcd->lock, flags);
787 			}
788 		}
789 	}
790 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
791 	return retval;
792 }
793 
794 /*
795  * Caller must NOT hold HCD spinlock.
796  */
797 static void
798 max3421_slow_retransmit(struct usb_hcd *hcd)
799 {
800 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
801 	struct urb *urb = max3421_hcd->curr_urb;
802 	struct max3421_ep *max3421_ep;
803 
804 	max3421_ep = urb->ep->hcpriv;
805 	max3421_ep->retransmit = 1;
806 	max3421_hcd->curr_urb = NULL;
807 }
808 
809 /*
810  * Caller must NOT hold HCD spinlock.
811  */
812 static void
813 max3421_recv_data_available(struct usb_hcd *hcd)
814 {
815 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
816 	struct urb *urb = max3421_hcd->curr_urb;
817 	size_t remaining, transfer_size;
818 	u8 rcvbc;
819 
820 	rcvbc = spi_rd8(hcd, MAX3421_REG_RCVBC);
821 
822 	if (rcvbc > MAX3421_FIFO_SIZE)
823 		rcvbc = MAX3421_FIFO_SIZE;
824 	if (urb->actual_length >= urb->transfer_buffer_length)
825 		remaining = 0;
826 	else
827 		remaining = urb->transfer_buffer_length - urb->actual_length;
828 	transfer_size = rcvbc;
829 	if (transfer_size > remaining)
830 		transfer_size = remaining;
831 	if (transfer_size > 0) {
832 		void *dst = urb->transfer_buffer + urb->actual_length;
833 
834 		spi_rd_buf(hcd, MAX3421_REG_RCVFIFO, dst, transfer_size);
835 		urb->actual_length += transfer_size;
836 		max3421_hcd->curr_len = transfer_size;
837 	}
838 
839 	/* ack the RCVDAV irq now that the FIFO has been read: */
840 	spi_wr8(hcd, MAX3421_REG_HIRQ, BIT(MAX3421_HI_RCVDAV_BIT));
841 }
842 
843 static void
844 max3421_handle_error(struct usb_hcd *hcd, u8 hrsl)
845 {
846 	struct spi_device *spi = to_spi_device(hcd->self.controller);
847 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
848 	u8 result_code = hrsl & MAX3421_HRSL_RESULT_MASK;
849 	struct urb *urb = max3421_hcd->curr_urb;
850 	struct max3421_ep *max3421_ep = urb->ep->hcpriv;
851 	int switch_sndfifo;
852 
853 	/*
854 	 * If an OUT command results in any response other than OK
855 	 * (i.e., error or NAK), we have to perform a dummy-write to
856 	 * SNDBC so the FIFO gets switched back to us.  Otherwise, we
857 	 * get out of sync with the SNDFIFO double buffer.
858 	 */
859 	switch_sndfifo = (max3421_ep->pkt_state == PKT_STATE_TRANSFER &&
860 			  usb_urb_dir_out(urb));
861 
862 	switch (result_code) {
863 	case MAX3421_HRSL_OK:
864 		return;			/* this shouldn't happen */
865 
866 	case MAX3421_HRSL_WRONGPID:	/* received wrong PID */
867 	case MAX3421_HRSL_BUSY:		/* SIE busy */
868 	case MAX3421_HRSL_BADREQ:	/* bad val in HXFR */
869 	case MAX3421_HRSL_UNDEF:	/* reserved */
870 	case MAX3421_HRSL_KERR:		/* K-state instead of response */
871 	case MAX3421_HRSL_JERR:		/* J-state instead of response */
872 		/*
873 		 * packet experienced an error that we cannot recover
874 		 * from; report error
875 		 */
876 		max3421_hcd->urb_done = hrsl_to_error[result_code];
877 		dev_dbg(&spi->dev, "%s: unexpected error HRSL=0x%02x",
878 			__func__, hrsl);
879 		break;
880 
881 	case MAX3421_HRSL_TOGERR:
882 		if (usb_urb_dir_in(urb))
883 			; /* don't do anything (device will switch toggle) */
884 		else {
885 			/* flip the send toggle bit: */
886 			int sndtog = (hrsl >> MAX3421_HRSL_SNDTOGRD_BIT) & 1;
887 
888 			sndtog ^= 1;
889 			spi_wr8(hcd, MAX3421_REG_HCTL,
890 				BIT(sndtog + MAX3421_HCTL_SNDTOG0_BIT));
891 		}
892 		fallthrough;
893 	case MAX3421_HRSL_BADBC:	/* bad byte count */
894 	case MAX3421_HRSL_PIDERR:	/* received PID is corrupted */
895 	case MAX3421_HRSL_PKTERR:	/* packet error (stuff, EOP) */
896 	case MAX3421_HRSL_CRCERR:	/* CRC error */
897 	case MAX3421_HRSL_BABBLE:	/* device talked too long */
898 	case MAX3421_HRSL_TIMEOUT:
899 		if (max3421_ep->retries++ < USB_MAX_RETRIES)
900 			/* retry the packet again in the next frame */
901 			max3421_slow_retransmit(hcd);
902 		else {
903 			/* Based on ohci.h cc_to_err[]: */
904 			max3421_hcd->urb_done = hrsl_to_error[result_code];
905 			dev_dbg(&spi->dev, "%s: unexpected error HRSL=0x%02x",
906 				__func__, hrsl);
907 		}
908 		break;
909 
910 	case MAX3421_HRSL_STALL:
911 		dev_dbg(&spi->dev, "%s: unexpected error HRSL=0x%02x",
912 			__func__, hrsl);
913 		max3421_hcd->urb_done = hrsl_to_error[result_code];
914 		break;
915 
916 	case MAX3421_HRSL_NAK:
917 		/*
918 		 * Device wasn't ready for data or has no data
919 		 * available: retry the packet again.
920 		 */
921 		max3421_next_transfer(hcd, 1);
922 		switch_sndfifo = 0;
923 		break;
924 	}
925 	if (switch_sndfifo)
926 		spi_wr8(hcd, MAX3421_REG_SNDBC, 0);
927 }
928 
929 /*
930  * Caller must NOT hold HCD spinlock.
931  */
932 static int
933 max3421_transfer_in_done(struct usb_hcd *hcd, struct urb *urb)
934 {
935 	struct spi_device *spi = to_spi_device(hcd->self.controller);
936 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
937 	u32 max_packet;
938 
939 	if (urb->actual_length >= urb->transfer_buffer_length)
940 		return 1;	/* read is complete, so we're done */
941 
942 	/*
943 	 * USB 2.0 Section 5.3.2 Pipes: packets must be full size
944 	 * except for last one.
945 	 */
946 	max_packet = usb_maxpacket(urb->dev, urb->pipe);
947 	if (max_packet > MAX3421_FIFO_SIZE) {
948 		/*
949 		 * We do not support isochronous transfers at this
950 		 * time...
951 		 */
952 		dev_err(&spi->dev,
953 			"%s: packet-size of %u too big (limit is %u bytes)",
954 			__func__, max_packet, MAX3421_FIFO_SIZE);
955 		return -EINVAL;
956 	}
957 
958 	if (max3421_hcd->curr_len < max_packet) {
959 		if (urb->transfer_flags & URB_SHORT_NOT_OK) {
960 			/*
961 			 * remaining > 0 and received an
962 			 * unexpected partial packet ->
963 			 * error
964 			 */
965 			return -EREMOTEIO;
966 		} else
967 			/* short read, but it's OK */
968 			return 1;
969 	}
970 	return 0;	/* not done */
971 }
972 
973 /*
974  * Caller must NOT hold HCD spinlock.
975  */
976 static int
977 max3421_transfer_out_done(struct usb_hcd *hcd, struct urb *urb)
978 {
979 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
980 
981 	urb->actual_length += max3421_hcd->curr_len;
982 	if (urb->actual_length < urb->transfer_buffer_length)
983 		return 0;
984 	if (urb->transfer_flags & URB_ZERO_PACKET) {
985 		/*
986 		 * Some hardware needs a zero-size packet at the end
987 		 * of a bulk-out transfer if the last transfer was a
988 		 * full-sized packet (i.e., such hardware use <
989 		 * max_packet as an indicator that the end of the
990 		 * packet has been reached).
991 		 */
992 		u32 max_packet = usb_maxpacket(urb->dev, urb->pipe);
993 
994 		if (max3421_hcd->curr_len == max_packet)
995 			return 0;
996 	}
997 	return 1;
998 }
999 
1000 /*
1001  * Caller must NOT hold HCD spinlock.
1002  */
1003 static void
1004 max3421_host_transfer_done(struct usb_hcd *hcd)
1005 {
1006 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1007 	struct urb *urb = max3421_hcd->curr_urb;
1008 	struct max3421_ep *max3421_ep;
1009 	u8 result_code, hrsl;
1010 	int urb_done = 0;
1011 
1012 	max3421_hcd->hien &= ~(BIT(MAX3421_HI_HXFRDN_BIT) |
1013 			       BIT(MAX3421_HI_RCVDAV_BIT));
1014 
1015 	hrsl = spi_rd8(hcd, MAX3421_REG_HRSL);
1016 	result_code = hrsl & MAX3421_HRSL_RESULT_MASK;
1017 
1018 #ifdef DEBUG
1019 	++max3421_hcd->err_stat[result_code];
1020 #endif
1021 
1022 	max3421_ep = urb->ep->hcpriv;
1023 
1024 	if (unlikely(result_code != MAX3421_HRSL_OK)) {
1025 		max3421_handle_error(hcd, hrsl);
1026 		return;
1027 	}
1028 
1029 	max3421_ep->naks = 0;
1030 	max3421_ep->retries = 0;
1031 	switch (max3421_ep->pkt_state) {
1032 
1033 	case PKT_STATE_SETUP:
1034 		if (urb->transfer_buffer_length > 0)
1035 			max3421_ep->pkt_state = PKT_STATE_TRANSFER;
1036 		else
1037 			max3421_ep->pkt_state = PKT_STATE_TERMINATE;
1038 		break;
1039 
1040 	case PKT_STATE_TRANSFER:
1041 		if (usb_urb_dir_in(urb))
1042 			urb_done = max3421_transfer_in_done(hcd, urb);
1043 		else
1044 			urb_done = max3421_transfer_out_done(hcd, urb);
1045 		if (urb_done > 0 && usb_pipetype(urb->pipe) == PIPE_CONTROL) {
1046 			/*
1047 			 * We aren't really done - we still need to
1048 			 * terminate the control transfer:
1049 			 */
1050 			max3421_hcd->urb_done = urb_done = 0;
1051 			max3421_ep->pkt_state = PKT_STATE_TERMINATE;
1052 		}
1053 		break;
1054 
1055 	case PKT_STATE_TERMINATE:
1056 		urb_done = 1;
1057 		break;
1058 	}
1059 
1060 	if (urb_done)
1061 		max3421_hcd->urb_done = urb_done;
1062 	else
1063 		max3421_next_transfer(hcd, 0);
1064 }
1065 
1066 /*
1067  * Caller must NOT hold HCD spinlock.
1068  */
1069 static void
1070 max3421_detect_conn(struct usb_hcd *hcd)
1071 {
1072 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1073 	unsigned int jk, have_conn = 0;
1074 	u32 old_port_status, chg;
1075 	unsigned long flags;
1076 	u8 hrsl, mode;
1077 
1078 	hrsl = spi_rd8(hcd, MAX3421_REG_HRSL);
1079 
1080 	jk = ((((hrsl >> MAX3421_HRSL_JSTATUS_BIT) & 1) << 0) |
1081 	      (((hrsl >> MAX3421_HRSL_KSTATUS_BIT) & 1) << 1));
1082 
1083 	mode = max3421_hcd->mode;
1084 
1085 	switch (jk) {
1086 	case 0x0: /* SE0: disconnect */
1087 		/*
1088 		 * Turn off SOFKAENAB bit to avoid getting interrupt
1089 		 * every milli-second:
1090 		 */
1091 		mode &= ~BIT(MAX3421_MODE_SOFKAENAB_BIT);
1092 		break;
1093 
1094 	case 0x1: /* J=0,K=1: low-speed (in full-speed or vice versa) */
1095 	case 0x2: /* J=1,K=0: full-speed (in full-speed or vice versa) */
1096 		if (jk == 0x2)
1097 			/* need to switch to the other speed: */
1098 			mode ^= BIT(MAX3421_MODE_LOWSPEED_BIT);
1099 		/* turn on SOFKAENAB bit: */
1100 		mode |= BIT(MAX3421_MODE_SOFKAENAB_BIT);
1101 		have_conn = 1;
1102 		break;
1103 
1104 	case 0x3: /* illegal */
1105 		break;
1106 	}
1107 
1108 	max3421_hcd->mode = mode;
1109 	spi_wr8(hcd, MAX3421_REG_MODE, max3421_hcd->mode);
1110 
1111 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1112 	old_port_status = max3421_hcd->port_status;
1113 	if (have_conn)
1114 		max3421_hcd->port_status |=  USB_PORT_STAT_CONNECTION;
1115 	else
1116 		max3421_hcd->port_status &= ~USB_PORT_STAT_CONNECTION;
1117 	if (mode & BIT(MAX3421_MODE_LOWSPEED_BIT))
1118 		max3421_hcd->port_status |=  USB_PORT_STAT_LOW_SPEED;
1119 	else
1120 		max3421_hcd->port_status &= ~USB_PORT_STAT_LOW_SPEED;
1121 	chg = (old_port_status ^ max3421_hcd->port_status);
1122 	max3421_hcd->port_status |= chg << 16;
1123 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1124 }
1125 
1126 static irqreturn_t
1127 max3421_irq_handler(int irq, void *dev_id)
1128 {
1129 	struct usb_hcd *hcd = dev_id;
1130 	struct spi_device *spi = to_spi_device(hcd->self.controller);
1131 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1132 
1133 	if (max3421_hcd->spi_thread)
1134 		wake_up_process(max3421_hcd->spi_thread);
1135 	if (!test_and_set_bit(ENABLE_IRQ, &max3421_hcd->todo))
1136 		disable_irq_nosync(spi->irq);
1137 	return IRQ_HANDLED;
1138 }
1139 
1140 #ifdef DEBUG
1141 
1142 static void
1143 dump_eps(struct usb_hcd *hcd)
1144 {
1145 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1146 	struct max3421_ep *max3421_ep;
1147 	struct usb_host_endpoint *ep;
1148 	char ubuf[512], *dp, *end;
1149 	unsigned long flags;
1150 	struct urb *urb;
1151 	int epnum, ret;
1152 
1153 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1154 	list_for_each_entry(max3421_ep, &max3421_hcd->ep_list, ep_list) {
1155 		ep = max3421_ep->ep;
1156 
1157 		dp = ubuf;
1158 		end = dp + sizeof(ubuf);
1159 		*dp = '\0';
1160 		list_for_each_entry(urb, &ep->urb_list, urb_list) {
1161 			ret = snprintf(dp, end - dp, " %p(%d.%s %d/%d)", urb,
1162 				       usb_pipetype(urb->pipe),
1163 				       usb_urb_dir_in(urb) ? "IN" : "OUT",
1164 				       urb->actual_length,
1165 				       urb->transfer_buffer_length);
1166 			if (ret < 0 || ret >= end - dp)
1167 				break;	/* error or buffer full */
1168 			dp += ret;
1169 		}
1170 
1171 		epnum = usb_endpoint_num(&ep->desc);
1172 		pr_info("EP%0u %u lst %04u rtr %u nak %6u rxmt %u: %s\n",
1173 			epnum, max3421_ep->pkt_state, max3421_ep->last_active,
1174 			max3421_ep->retries, max3421_ep->naks,
1175 			max3421_ep->retransmit, ubuf);
1176 	}
1177 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1178 }
1179 
1180 #endif /* DEBUG */
1181 
1182 /* Return zero if no work was performed, 1 otherwise.  */
1183 static int
1184 max3421_handle_irqs(struct usb_hcd *hcd)
1185 {
1186 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1187 	u32 chg, old_port_status;
1188 	unsigned long flags;
1189 	u8 hirq;
1190 
1191 	/*
1192 	 * Read and ack pending interrupts (CPU must never
1193 	 * clear SNDBAV directly and RCVDAV must be cleared by
1194 	 * max3421_recv_data_available()!):
1195 	 */
1196 	hirq = spi_rd8(hcd, MAX3421_REG_HIRQ);
1197 	hirq &= max3421_hcd->hien;
1198 	if (!hirq)
1199 		return 0;
1200 
1201 	spi_wr8(hcd, MAX3421_REG_HIRQ,
1202 		hirq & ~(BIT(MAX3421_HI_SNDBAV_BIT) |
1203 			 BIT(MAX3421_HI_RCVDAV_BIT)));
1204 
1205 	if (hirq & BIT(MAX3421_HI_FRAME_BIT)) {
1206 		max3421_hcd->frame_number = ((max3421_hcd->frame_number + 1)
1207 					     & USB_MAX_FRAME_NUMBER);
1208 		max3421_hcd->sched_pass = SCHED_PASS_PERIODIC;
1209 	}
1210 
1211 	if (hirq & BIT(MAX3421_HI_RCVDAV_BIT))
1212 		max3421_recv_data_available(hcd);
1213 
1214 	if (hirq & BIT(MAX3421_HI_HXFRDN_BIT))
1215 		max3421_host_transfer_done(hcd);
1216 
1217 	if (hirq & BIT(MAX3421_HI_CONDET_BIT))
1218 		max3421_detect_conn(hcd);
1219 
1220 	/*
1221 	 * Now process interrupts that may affect HCD state
1222 	 * other than the end-points:
1223 	 */
1224 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1225 
1226 	old_port_status = max3421_hcd->port_status;
1227 	if (hirq & BIT(MAX3421_HI_BUSEVENT_BIT)) {
1228 		if (max3421_hcd->port_status & USB_PORT_STAT_RESET) {
1229 			/* BUSEVENT due to completion of Bus Reset */
1230 			max3421_hcd->port_status &= ~USB_PORT_STAT_RESET;
1231 			max3421_hcd->port_status |=  USB_PORT_STAT_ENABLE;
1232 		} else {
1233 			/* BUSEVENT due to completion of Bus Resume */
1234 			pr_info("%s: BUSEVENT Bus Resume Done\n", __func__);
1235 		}
1236 	}
1237 	if (hirq & BIT(MAX3421_HI_RWU_BIT))
1238 		pr_info("%s: RWU\n", __func__);
1239 	if (hirq & BIT(MAX3421_HI_SUSDN_BIT))
1240 		pr_info("%s: SUSDN\n", __func__);
1241 
1242 	chg = (old_port_status ^ max3421_hcd->port_status);
1243 	max3421_hcd->port_status |= chg << 16;
1244 
1245 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1246 
1247 #ifdef DEBUG
1248 	{
1249 		static unsigned long last_time;
1250 		char sbuf[16 * 16], *dp, *end;
1251 		int i;
1252 
1253 		if (time_after(jiffies, last_time + 5*HZ)) {
1254 			dp = sbuf;
1255 			end = sbuf + sizeof(sbuf);
1256 			*dp = '\0';
1257 			for (i = 0; i < 16; ++i) {
1258 				int ret = snprintf(dp, end - dp, " %lu",
1259 						   max3421_hcd->err_stat[i]);
1260 				if (ret < 0 || ret >= end - dp)
1261 					break;	/* error or buffer full */
1262 				dp += ret;
1263 			}
1264 			pr_info("%s: hrsl_stats %s\n", __func__, sbuf);
1265 			memset(max3421_hcd->err_stat, 0,
1266 			       sizeof(max3421_hcd->err_stat));
1267 			last_time = jiffies;
1268 
1269 			dump_eps(hcd);
1270 		}
1271 	}
1272 #endif
1273 	return 1;
1274 }
1275 
1276 static int
1277 max3421_reset_hcd(struct usb_hcd *hcd)
1278 {
1279 	struct spi_device *spi = to_spi_device(hcd->self.controller);
1280 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1281 	int timeout;
1282 
1283 	/* perform a chip reset and wait for OSCIRQ signal to appear: */
1284 	spi_wr8(hcd, MAX3421_REG_USBCTL, BIT(MAX3421_USBCTL_CHIPRES_BIT));
1285 	/* clear reset: */
1286 	spi_wr8(hcd, MAX3421_REG_USBCTL, 0);
1287 	timeout = 1000;
1288 	while (1) {
1289 		if (spi_rd8(hcd, MAX3421_REG_USBIRQ)
1290 		    & BIT(MAX3421_USBIRQ_OSCOKIRQ_BIT))
1291 			break;
1292 		if (--timeout < 0) {
1293 			dev_err(&spi->dev,
1294 				"timed out waiting for oscillator OK signal");
1295 			return 1;
1296 		}
1297 		cond_resched();
1298 	}
1299 
1300 	/*
1301 	 * Turn on host mode, automatic generation of SOF packets, and
1302 	 * enable pull-down registers on DM/DP:
1303 	 */
1304 	max3421_hcd->mode = (BIT(MAX3421_MODE_HOST_BIT) |
1305 			     BIT(MAX3421_MODE_SOFKAENAB_BIT) |
1306 			     BIT(MAX3421_MODE_DMPULLDN_BIT) |
1307 			     BIT(MAX3421_MODE_DPPULLDN_BIT));
1308 	spi_wr8(hcd, MAX3421_REG_MODE, max3421_hcd->mode);
1309 
1310 	/* reset frame-number: */
1311 	max3421_hcd->frame_number = USB_MAX_FRAME_NUMBER;
1312 	spi_wr8(hcd, MAX3421_REG_HCTL, BIT(MAX3421_HCTL_FRMRST_BIT));
1313 
1314 	/* sample the state of the D+ and D- lines */
1315 	spi_wr8(hcd, MAX3421_REG_HCTL, BIT(MAX3421_HCTL_SAMPLEBUS_BIT));
1316 	max3421_detect_conn(hcd);
1317 
1318 	/* enable frame, connection-detected, and bus-event interrupts: */
1319 	max3421_hcd->hien = (BIT(MAX3421_HI_FRAME_BIT) |
1320 			     BIT(MAX3421_HI_CONDET_BIT) |
1321 			     BIT(MAX3421_HI_BUSEVENT_BIT));
1322 	spi_wr8(hcd, MAX3421_REG_HIEN, max3421_hcd->hien);
1323 
1324 	/* enable interrupts: */
1325 	spi_wr8(hcd, MAX3421_REG_CPUCTL, BIT(MAX3421_CPUCTL_IE_BIT));
1326 	return 1;
1327 }
1328 
1329 static int
1330 max3421_urb_done(struct usb_hcd *hcd)
1331 {
1332 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1333 	unsigned long flags;
1334 	struct urb *urb;
1335 	int status;
1336 
1337 	status = max3421_hcd->urb_done;
1338 	max3421_hcd->urb_done = 0;
1339 	if (status > 0)
1340 		status = 0;
1341 	urb = max3421_hcd->curr_urb;
1342 	if (urb) {
1343 		/* save the old end-points toggles: */
1344 		u8 hrsl = spi_rd8(hcd, MAX3421_REG_HRSL);
1345 		int rcvtog = (hrsl >> MAX3421_HRSL_RCVTOGRD_BIT) & 1;
1346 		int sndtog = (hrsl >> MAX3421_HRSL_SNDTOGRD_BIT) & 1;
1347 		int epnum = usb_endpoint_num(&urb->ep->desc);
1348 
1349 		/* no locking: HCD (i.e., we) own toggles, don't we? */
1350 		usb_settoggle(urb->dev, epnum, 0, rcvtog);
1351 		usb_settoggle(urb->dev, epnum, 1, sndtog);
1352 
1353 		max3421_hcd->curr_urb = NULL;
1354 		spin_lock_irqsave(&max3421_hcd->lock, flags);
1355 		usb_hcd_unlink_urb_from_ep(hcd, urb);
1356 		spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1357 
1358 		/* must be called without the HCD spinlock: */
1359 		usb_hcd_giveback_urb(hcd, urb, status);
1360 	}
1361 	return 1;
1362 }
1363 
1364 static int
1365 max3421_spi_thread(void *dev_id)
1366 {
1367 	struct usb_hcd *hcd = dev_id;
1368 	struct spi_device *spi = to_spi_device(hcd->self.controller);
1369 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1370 	int i, i_worked = 1;
1371 
1372 	/* set full-duplex SPI mode, low-active interrupt pin: */
1373 	spi_wr8(hcd, MAX3421_REG_PINCTL,
1374 		(BIT(MAX3421_PINCTL_FDUPSPI_BIT) |	/* full-duplex */
1375 		 BIT(MAX3421_PINCTL_INTLEVEL_BIT)));	/* low-active irq */
1376 
1377 	while (!kthread_should_stop()) {
1378 		max3421_hcd->rev = spi_rd8(hcd, MAX3421_REG_REVISION);
1379 		if (max3421_hcd->rev == 0x12 || max3421_hcd->rev == 0x13)
1380 			break;
1381 		dev_err(&spi->dev, "bad rev 0x%02x", max3421_hcd->rev);
1382 		msleep(10000);
1383 	}
1384 	dev_info(&spi->dev, "rev 0x%x, SPI clk %dHz, bpw %u, irq %d\n",
1385 		 max3421_hcd->rev, spi->max_speed_hz, spi->bits_per_word,
1386 		 spi->irq);
1387 
1388 	while (!kthread_should_stop()) {
1389 		if (!i_worked) {
1390 			/*
1391 			 * We'll be waiting for wakeups from the hard
1392 			 * interrupt handler, so now is a good time to
1393 			 * sync our hien with the chip:
1394 			 */
1395 			spi_wr8(hcd, MAX3421_REG_HIEN, max3421_hcd->hien);
1396 
1397 			set_current_state(TASK_INTERRUPTIBLE);
1398 			if (test_and_clear_bit(ENABLE_IRQ, &max3421_hcd->todo))
1399 				enable_irq(spi->irq);
1400 			schedule();
1401 			__set_current_state(TASK_RUNNING);
1402 		}
1403 
1404 		i_worked = 0;
1405 
1406 		if (max3421_hcd->urb_done)
1407 			i_worked |= max3421_urb_done(hcd);
1408 		else if (max3421_handle_irqs(hcd))
1409 			i_worked = 1;
1410 		else if (!max3421_hcd->curr_urb)
1411 			i_worked |= max3421_select_and_start_urb(hcd);
1412 
1413 		if (test_and_clear_bit(RESET_HCD, &max3421_hcd->todo))
1414 			/* reset the HCD: */
1415 			i_worked |= max3421_reset_hcd(hcd);
1416 		if (test_and_clear_bit(RESET_PORT, &max3421_hcd->todo)) {
1417 			/* perform a USB bus reset: */
1418 			spi_wr8(hcd, MAX3421_REG_HCTL,
1419 				BIT(MAX3421_HCTL_BUSRST_BIT));
1420 			i_worked = 1;
1421 		}
1422 		if (test_and_clear_bit(CHECK_UNLINK, &max3421_hcd->todo))
1423 			i_worked |= max3421_check_unlink(hcd);
1424 		if (test_and_clear_bit(IOPIN_UPDATE, &max3421_hcd->todo)) {
1425 			/*
1426 			 * IOPINS1/IOPINS2 do not auto-increment, so we can't
1427 			 * use spi_wr_buf().
1428 			 */
1429 			for (i = 0; i < ARRAY_SIZE(max3421_hcd->iopins); ++i) {
1430 				u8 val = spi_rd8(hcd, MAX3421_REG_IOPINS1 + i);
1431 
1432 				val = ((val & 0xf0) |
1433 				       (max3421_hcd->iopins[i] & 0x0f));
1434 				spi_wr8(hcd, MAX3421_REG_IOPINS1 + i, val);
1435 				max3421_hcd->iopins[i] = val;
1436 			}
1437 			i_worked = 1;
1438 		}
1439 	}
1440 	set_current_state(TASK_RUNNING);
1441 	dev_info(&spi->dev, "SPI thread exiting");
1442 	return 0;
1443 }
1444 
1445 static int
1446 max3421_reset_port(struct usb_hcd *hcd)
1447 {
1448 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1449 
1450 	max3421_hcd->port_status &= ~(USB_PORT_STAT_ENABLE |
1451 				      USB_PORT_STAT_LOW_SPEED);
1452 	max3421_hcd->port_status |= USB_PORT_STAT_RESET;
1453 	set_bit(RESET_PORT, &max3421_hcd->todo);
1454 	wake_up_process(max3421_hcd->spi_thread);
1455 	return 0;
1456 }
1457 
1458 static int
1459 max3421_reset(struct usb_hcd *hcd)
1460 {
1461 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1462 
1463 	hcd->self.sg_tablesize = 0;
1464 	hcd->speed = HCD_USB2;
1465 	hcd->self.root_hub->speed = USB_SPEED_FULL;
1466 	set_bit(RESET_HCD, &max3421_hcd->todo);
1467 	wake_up_process(max3421_hcd->spi_thread);
1468 	return 0;
1469 }
1470 
1471 static int
1472 max3421_start(struct usb_hcd *hcd)
1473 {
1474 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1475 
1476 	spin_lock_init(&max3421_hcd->lock);
1477 	max3421_hcd->rh_state = MAX3421_RH_RUNNING;
1478 
1479 	INIT_LIST_HEAD(&max3421_hcd->ep_list);
1480 
1481 	hcd->power_budget = POWER_BUDGET;
1482 	hcd->state = HC_STATE_RUNNING;
1483 	hcd->uses_new_polling = 1;
1484 	return 0;
1485 }
1486 
1487 static void
1488 max3421_stop(struct usb_hcd *hcd)
1489 {
1490 }
1491 
1492 static int
1493 max3421_urb_enqueue(struct usb_hcd *hcd, struct urb *urb, gfp_t mem_flags)
1494 {
1495 	struct spi_device *spi = to_spi_device(hcd->self.controller);
1496 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1497 	struct max3421_ep *max3421_ep;
1498 	unsigned long flags;
1499 	int retval;
1500 
1501 	switch (usb_pipetype(urb->pipe)) {
1502 	case PIPE_INTERRUPT:
1503 	case PIPE_ISOCHRONOUS:
1504 		if (urb->interval < 0) {
1505 			dev_err(&spi->dev,
1506 			  "%s: interval=%d for intr-/iso-pipe; expected > 0\n",
1507 				__func__, urb->interval);
1508 			return -EINVAL;
1509 		}
1510 		break;
1511 	default:
1512 		break;
1513 	}
1514 
1515 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1516 
1517 	max3421_ep = urb->ep->hcpriv;
1518 	if (!max3421_ep) {
1519 		/* gets freed in max3421_endpoint_disable: */
1520 		max3421_ep = kzalloc(sizeof(struct max3421_ep), GFP_ATOMIC);
1521 		if (!max3421_ep) {
1522 			retval = -ENOMEM;
1523 			goto out;
1524 		}
1525 		max3421_ep->ep = urb->ep;
1526 		max3421_ep->last_active = max3421_hcd->frame_number;
1527 		urb->ep->hcpriv = max3421_ep;
1528 
1529 		list_add_tail(&max3421_ep->ep_list, &max3421_hcd->ep_list);
1530 	}
1531 
1532 	retval = usb_hcd_link_urb_to_ep(hcd, urb);
1533 	if (retval == 0) {
1534 		/* Since we added to the queue, restart scheduling: */
1535 		max3421_hcd->sched_pass = SCHED_PASS_PERIODIC;
1536 		wake_up_process(max3421_hcd->spi_thread);
1537 	}
1538 
1539 out:
1540 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1541 	return retval;
1542 }
1543 
1544 static int
1545 max3421_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
1546 {
1547 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1548 	unsigned long flags;
1549 	int retval;
1550 
1551 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1552 
1553 	/*
1554 	 * This will set urb->unlinked which in turn causes the entry
1555 	 * to be dropped at the next opportunity.
1556 	 */
1557 	retval = usb_hcd_check_unlink_urb(hcd, urb, status);
1558 	if (retval == 0) {
1559 		set_bit(CHECK_UNLINK, &max3421_hcd->todo);
1560 		wake_up_process(max3421_hcd->spi_thread);
1561 	}
1562 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1563 	return retval;
1564 }
1565 
1566 static void
1567 max3421_endpoint_disable(struct usb_hcd *hcd, struct usb_host_endpoint *ep)
1568 {
1569 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1570 	unsigned long flags;
1571 
1572 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1573 
1574 	if (ep->hcpriv) {
1575 		struct max3421_ep *max3421_ep = ep->hcpriv;
1576 
1577 		/* remove myself from the ep_list: */
1578 		if (!list_empty(&max3421_ep->ep_list))
1579 			list_del(&max3421_ep->ep_list);
1580 		kfree(max3421_ep);
1581 		ep->hcpriv = NULL;
1582 	}
1583 
1584 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1585 }
1586 
1587 static int
1588 max3421_get_frame_number(struct usb_hcd *hcd)
1589 {
1590 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1591 	return max3421_hcd->frame_number;
1592 }
1593 
1594 /*
1595  * Should return a non-zero value when any port is undergoing a resume
1596  * transition while the root hub is suspended.
1597  */
1598 static int
1599 max3421_hub_status_data(struct usb_hcd *hcd, char *buf)
1600 {
1601 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1602 	unsigned long flags;
1603 	int retval = 0;
1604 
1605 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1606 	if (!HCD_HW_ACCESSIBLE(hcd))
1607 		goto done;
1608 
1609 	*buf = 0;
1610 	if ((max3421_hcd->port_status & PORT_C_MASK) != 0) {
1611 		*buf = (1 << 1); /* a hub over-current condition exists */
1612 		dev_dbg(hcd->self.controller,
1613 			"port status 0x%08x has changes\n",
1614 			max3421_hcd->port_status);
1615 		retval = 1;
1616 		if (max3421_hcd->rh_state == MAX3421_RH_SUSPENDED)
1617 			usb_hcd_resume_root_hub(hcd);
1618 	}
1619 done:
1620 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1621 	return retval;
1622 }
1623 
1624 static inline void
1625 hub_descriptor(struct usb_hub_descriptor *desc)
1626 {
1627 	memset(desc, 0, sizeof(*desc));
1628 	/*
1629 	 * See Table 11-13: Hub Descriptor in USB 2.0 spec.
1630 	 */
1631 	desc->bDescriptorType = USB_DT_HUB; /* hub descriptor */
1632 	desc->bDescLength = 9;
1633 	desc->wHubCharacteristics = cpu_to_le16(HUB_CHAR_INDV_PORT_LPSM |
1634 						HUB_CHAR_COMMON_OCPM);
1635 	desc->bNbrPorts = 1;
1636 }
1637 
1638 /*
1639  * Set the MAX3421E general-purpose output with number PIN_NUMBER to
1640  * VALUE (0 or 1).  PIN_NUMBER may be in the range from 1-8.  For
1641  * any other value, this function acts as a no-op.
1642  */
1643 static void
1644 max3421_gpout_set_value(struct usb_hcd *hcd, u8 pin_number, u8 value)
1645 {
1646 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1647 	u8 mask, idx;
1648 
1649 	--pin_number;
1650 	if (pin_number >= MAX3421_GPOUT_COUNT)
1651 		return;
1652 
1653 	mask = 1u << (pin_number % 4);
1654 	idx = pin_number / 4;
1655 
1656 	if (value)
1657 		max3421_hcd->iopins[idx] |=  mask;
1658 	else
1659 		max3421_hcd->iopins[idx] &= ~mask;
1660 	set_bit(IOPIN_UPDATE, &max3421_hcd->todo);
1661 	wake_up_process(max3421_hcd->spi_thread);
1662 }
1663 
1664 static int
1665 max3421_hub_control(struct usb_hcd *hcd, u16 type_req, u16 value, u16 index,
1666 		    char *buf, u16 length)
1667 {
1668 	struct spi_device *spi = to_spi_device(hcd->self.controller);
1669 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1670 	struct max3421_hcd_platform_data *pdata;
1671 	unsigned long flags;
1672 	int retval = 0;
1673 
1674 	pdata = spi->dev.platform_data;
1675 
1676 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1677 
1678 	switch (type_req) {
1679 	case ClearHubFeature:
1680 		break;
1681 	case ClearPortFeature:
1682 		switch (value) {
1683 		case USB_PORT_FEAT_SUSPEND:
1684 			break;
1685 		case USB_PORT_FEAT_POWER:
1686 			dev_dbg(hcd->self.controller, "power-off\n");
1687 			max3421_gpout_set_value(hcd, pdata->vbus_gpout,
1688 						!pdata->vbus_active_level);
1689 			fallthrough;
1690 		default:
1691 			max3421_hcd->port_status &= ~(1 << value);
1692 		}
1693 		break;
1694 	case GetHubDescriptor:
1695 		hub_descriptor((struct usb_hub_descriptor *) buf);
1696 		break;
1697 
1698 	case DeviceRequest | USB_REQ_GET_DESCRIPTOR:
1699 	case GetPortErrorCount:
1700 	case SetHubDepth:
1701 		/* USB3 only */
1702 		goto error;
1703 
1704 	case GetHubStatus:
1705 		*(__le32 *) buf = cpu_to_le32(0);
1706 		break;
1707 
1708 	case GetPortStatus:
1709 		if (index != 1) {
1710 			retval = -EPIPE;
1711 			goto error;
1712 		}
1713 		((__le16 *) buf)[0] = cpu_to_le16(max3421_hcd->port_status);
1714 		((__le16 *) buf)[1] =
1715 			cpu_to_le16(max3421_hcd->port_status >> 16);
1716 		break;
1717 
1718 	case SetHubFeature:
1719 		retval = -EPIPE;
1720 		break;
1721 
1722 	case SetPortFeature:
1723 		switch (value) {
1724 		case USB_PORT_FEAT_LINK_STATE:
1725 		case USB_PORT_FEAT_U1_TIMEOUT:
1726 		case USB_PORT_FEAT_U2_TIMEOUT:
1727 		case USB_PORT_FEAT_BH_PORT_RESET:
1728 			goto error;
1729 		case USB_PORT_FEAT_SUSPEND:
1730 			if (max3421_hcd->active)
1731 				max3421_hcd->port_status |=
1732 					USB_PORT_STAT_SUSPEND;
1733 			break;
1734 		case USB_PORT_FEAT_POWER:
1735 			dev_dbg(hcd->self.controller, "power-on\n");
1736 			max3421_hcd->port_status |= USB_PORT_STAT_POWER;
1737 			max3421_gpout_set_value(hcd, pdata->vbus_gpout,
1738 						pdata->vbus_active_level);
1739 			break;
1740 		case USB_PORT_FEAT_RESET:
1741 			max3421_reset_port(hcd);
1742 			fallthrough;
1743 		default:
1744 			if ((max3421_hcd->port_status & USB_PORT_STAT_POWER)
1745 			    != 0)
1746 				max3421_hcd->port_status |= (1 << value);
1747 		}
1748 		break;
1749 
1750 	default:
1751 		dev_dbg(hcd->self.controller,
1752 			"hub control req%04x v%04x i%04x l%d\n",
1753 			type_req, value, index, length);
1754 error:		/* "protocol stall" on error */
1755 		retval = -EPIPE;
1756 	}
1757 
1758 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1759 	return retval;
1760 }
1761 
1762 static int
1763 max3421_bus_suspend(struct usb_hcd *hcd)
1764 {
1765 	return -1;
1766 }
1767 
1768 static int
1769 max3421_bus_resume(struct usb_hcd *hcd)
1770 {
1771 	return -1;
1772 }
1773 
1774 static const struct hc_driver max3421_hcd_desc = {
1775 	.description =		"max3421",
1776 	.product_desc =		DRIVER_DESC,
1777 	.hcd_priv_size =	sizeof(struct max3421_hcd),
1778 	.flags =		HCD_USB11,
1779 	.reset =		max3421_reset,
1780 	.start =		max3421_start,
1781 	.stop =			max3421_stop,
1782 	.get_frame_number =	max3421_get_frame_number,
1783 	.urb_enqueue =		max3421_urb_enqueue,
1784 	.urb_dequeue =		max3421_urb_dequeue,
1785 	.endpoint_disable =	max3421_endpoint_disable,
1786 	.hub_status_data =	max3421_hub_status_data,
1787 	.hub_control =		max3421_hub_control,
1788 	.bus_suspend =		max3421_bus_suspend,
1789 	.bus_resume =		max3421_bus_resume,
1790 };
1791 
1792 static int
1793 max3421_of_vbus_en_pin(struct device *dev, struct max3421_hcd_platform_data *pdata)
1794 {
1795 	int retval;
1796 	uint32_t value[2];
1797 
1798 	if (!pdata)
1799 		return -EINVAL;
1800 
1801 	retval = of_property_read_u32_array(dev->of_node, "maxim,vbus-en-pin", value, 2);
1802 	if (retval) {
1803 		dev_err(dev, "device tree node property 'maxim,vbus-en-pin' is missing\n");
1804 		return retval;
1805 	}
1806 	dev_info(dev, "property 'maxim,vbus-en-pin' value is <%d %d>\n", value[0], value[1]);
1807 
1808 	pdata->vbus_gpout = value[0];
1809 	pdata->vbus_active_level = value[1];
1810 
1811 	return 0;
1812 }
1813 
1814 static int
1815 max3421_probe(struct spi_device *spi)
1816 {
1817 	struct device *dev = &spi->dev;
1818 	struct max3421_hcd *max3421_hcd;
1819 	struct usb_hcd *hcd = NULL;
1820 	struct max3421_hcd_platform_data *pdata = NULL;
1821 	int retval;
1822 
1823 	if (spi_setup(spi) < 0) {
1824 		dev_err(&spi->dev, "Unable to setup SPI bus");
1825 		return -EFAULT;
1826 	}
1827 
1828 	if (!spi->irq) {
1829 		dev_err(dev, "Failed to get SPI IRQ");
1830 		return -EFAULT;
1831 	}
1832 
1833 	if (IS_ENABLED(CONFIG_OF) && dev->of_node) {
1834 		pdata = devm_kzalloc(&spi->dev, sizeof(*pdata), GFP_KERNEL);
1835 		if (!pdata) {
1836 			retval = -ENOMEM;
1837 			goto error;
1838 		}
1839 		retval = max3421_of_vbus_en_pin(dev, pdata);
1840 		if (retval)
1841 			goto error;
1842 
1843 		spi->dev.platform_data = pdata;
1844 	}
1845 
1846 	pdata = spi->dev.platform_data;
1847 	if (!pdata) {
1848 		dev_err(&spi->dev, "driver configuration data is not provided\n");
1849 		retval = -EFAULT;
1850 		goto error;
1851 	}
1852 	if (pdata->vbus_active_level > 1) {
1853 		dev_err(&spi->dev, "vbus active level value %d is out of range (0/1)\n", pdata->vbus_active_level);
1854 		retval = -EINVAL;
1855 		goto error;
1856 	}
1857 	if (pdata->vbus_gpout < 1 || pdata->vbus_gpout > MAX3421_GPOUT_COUNT) {
1858 		dev_err(&spi->dev, "vbus gpout value %d is out of range (1..8)\n", pdata->vbus_gpout);
1859 		retval = -EINVAL;
1860 		goto error;
1861 	}
1862 
1863 	retval = -ENOMEM;
1864 	hcd = usb_create_hcd(&max3421_hcd_desc, &spi->dev,
1865 			     dev_name(&spi->dev));
1866 	if (!hcd) {
1867 		dev_err(&spi->dev, "failed to create HCD structure\n");
1868 		goto error;
1869 	}
1870 	set_bit(HCD_FLAG_POLL_RH, &hcd->flags);
1871 	max3421_hcd = hcd_to_max3421(hcd);
1872 	INIT_LIST_HEAD(&max3421_hcd->ep_list);
1873 	spi_set_drvdata(spi, max3421_hcd);
1874 
1875 	max3421_hcd->tx = kmalloc(sizeof(*max3421_hcd->tx), GFP_KERNEL);
1876 	if (!max3421_hcd->tx)
1877 		goto error;
1878 	max3421_hcd->rx = kmalloc(sizeof(*max3421_hcd->rx), GFP_KERNEL);
1879 	if (!max3421_hcd->rx)
1880 		goto error;
1881 
1882 	max3421_hcd->spi_thread = kthread_run(max3421_spi_thread, hcd,
1883 					      "max3421_spi_thread");
1884 	if (max3421_hcd->spi_thread == ERR_PTR(-ENOMEM)) {
1885 		dev_err(&spi->dev,
1886 			"failed to create SPI thread (out of memory)\n");
1887 		goto error;
1888 	}
1889 
1890 	retval = usb_add_hcd(hcd, 0, 0);
1891 	if (retval) {
1892 		dev_err(&spi->dev, "failed to add HCD\n");
1893 		goto error;
1894 	}
1895 
1896 	retval = request_irq(spi->irq, max3421_irq_handler,
1897 			     IRQF_TRIGGER_LOW, "max3421", hcd);
1898 	if (retval < 0) {
1899 		dev_err(&spi->dev, "failed to request irq %d\n", spi->irq);
1900 		goto error;
1901 	}
1902 	return 0;
1903 
1904 error:
1905 	if (IS_ENABLED(CONFIG_OF) && dev->of_node && pdata) {
1906 		devm_kfree(&spi->dev, pdata);
1907 		spi->dev.platform_data = NULL;
1908 	}
1909 
1910 	if (hcd) {
1911 		kfree(max3421_hcd->tx);
1912 		kfree(max3421_hcd->rx);
1913 		if (max3421_hcd->spi_thread)
1914 			kthread_stop(max3421_hcd->spi_thread);
1915 		usb_put_hcd(hcd);
1916 	}
1917 	return retval;
1918 }
1919 
1920 static void
1921 max3421_remove(struct spi_device *spi)
1922 {
1923 	struct max3421_hcd *max3421_hcd;
1924 	struct usb_hcd *hcd;
1925 	unsigned long flags;
1926 
1927 	max3421_hcd = spi_get_drvdata(spi);
1928 	hcd = max3421_to_hcd(max3421_hcd);
1929 
1930 	usb_remove_hcd(hcd);
1931 
1932 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1933 
1934 	kthread_stop(max3421_hcd->spi_thread);
1935 
1936 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1937 
1938 	free_irq(spi->irq, hcd);
1939 
1940 	usb_put_hcd(hcd);
1941 }
1942 
1943 static const struct of_device_id max3421_of_match_table[] = {
1944 	{ .compatible = "maxim,max3421", },
1945 	{},
1946 };
1947 MODULE_DEVICE_TABLE(of, max3421_of_match_table);
1948 
1949 static struct spi_driver max3421_driver = {
1950 	.probe		= max3421_probe,
1951 	.remove		= max3421_remove,
1952 	.driver		= {
1953 		.name	= "max3421-hcd",
1954 		.of_match_table = of_match_ptr(max3421_of_match_table),
1955 	},
1956 };
1957 
1958 module_spi_driver(max3421_driver);
1959 
1960 MODULE_DESCRIPTION(DRIVER_DESC);
1961 MODULE_AUTHOR("David Mosberger <davidm@egauge.net>");
1962 MODULE_LICENSE("GPL");
1963