xref: /openbmc/linux/drivers/usb/host/max3421-hcd.c (revision d9fd5a71)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * MAX3421 Host Controller driver for USB.
4  *
5  * Author: David Mosberger-Tang <davidm@egauge.net>
6  *
7  * (C) Copyright 2014 David Mosberger-Tang <davidm@egauge.net>
8  *
9  * MAX3421 is a chip implementing a USB 2.0 Full-/Low-Speed host
10  * controller on a SPI bus.
11  *
12  * Based on:
13  *	o MAX3421E datasheet
14  *		https://datasheets.maximintegrated.com/en/ds/MAX3421E.pdf
15  *	o MAX3421E Programming Guide
16  *		https://www.hdl.co.jp/ftpdata/utl-001/AN3785.pdf
17  *	o gadget/dummy_hcd.c
18  *		For USB HCD implementation.
19  *	o Arduino MAX3421 driver
20  *	     https://github.com/felis/USB_Host_Shield_2.0/blob/master/Usb.cpp
21  *
22  * This file is licenced under the GPL v2.
23  *
24  * Important note on worst-case (full-speed) packet size constraints
25  * (See USB 2.0 Section 5.6.3 and following):
26  *
27  *	- control:	  64 bytes
28  *	- isochronous:	1023 bytes
29  *	- interrupt:	  64 bytes
30  *	- bulk:		  64 bytes
31  *
32  * Since the MAX3421 FIFO size is 64 bytes, we do not have to work about
33  * multi-FIFO writes/reads for a single USB packet *except* for isochronous
34  * transfers.  We don't support isochronous transfers at this time, so we
35  * just assume that a USB packet always fits into a single FIFO buffer.
36  *
37  * NOTE: The June 2006 version of "MAX3421E Programming Guide"
38  * (AN3785) has conflicting info for the RCVDAVIRQ bit:
39  *
40  *	The description of RCVDAVIRQ says "The CPU *must* clear
41  *	this IRQ bit (by writing a 1 to it) before reading the
42  *	RCVFIFO data.
43  *
44  * However, the earlier section on "Programming BULK-IN
45  * Transfers" says * that:
46  *
47  *	After the CPU retrieves the data, it clears the
48  *	RCVDAVIRQ bit.
49  *
50  * The December 2006 version has been corrected and it consistently
51  * states the second behavior is the correct one.
52  *
53  * Synchronous SPI transactions sleep so we can't perform any such
54  * transactions while holding a spin-lock (and/or while interrupts are
55  * masked).  To achieve this, all SPI transactions are issued from a
56  * single thread (max3421_spi_thread).
57  */
58 
59 #include <linux/jiffies.h>
60 #include <linux/module.h>
61 #include <linux/spi/spi.h>
62 #include <linux/usb.h>
63 #include <linux/usb/hcd.h>
64 #include <linux/of.h>
65 
66 #include <linux/platform_data/max3421-hcd.h>
67 
68 #define DRIVER_DESC	"MAX3421 USB Host-Controller Driver"
69 #define DRIVER_VERSION	"1.0"
70 
71 /* 11-bit counter that wraps around (USB 2.0 Section 8.3.3): */
72 #define USB_MAX_FRAME_NUMBER	0x7ff
73 #define USB_MAX_RETRIES		3 /* # of retries before error is reported */
74 
75 /*
76  * Max. # of times we're willing to retransmit a request immediately in
77  * resposne to a NAK.  Afterwards, we fall back on trying once a frame.
78  */
79 #define NAK_MAX_FAST_RETRANSMITS	2
80 
81 #define POWER_BUDGET	500	/* in mA; use 8 for low-power port testing */
82 
83 /* Port-change mask: */
84 #define PORT_C_MASK	((USB_PORT_STAT_C_CONNECTION |	\
85 			  USB_PORT_STAT_C_ENABLE |	\
86 			  USB_PORT_STAT_C_SUSPEND |	\
87 			  USB_PORT_STAT_C_OVERCURRENT | \
88 			  USB_PORT_STAT_C_RESET) << 16)
89 
90 #define MAX3421_GPOUT_COUNT	8
91 
92 enum max3421_rh_state {
93 	MAX3421_RH_RESET,
94 	MAX3421_RH_SUSPENDED,
95 	MAX3421_RH_RUNNING
96 };
97 
98 enum pkt_state {
99 	PKT_STATE_SETUP,	/* waiting to send setup packet to ctrl pipe */
100 	PKT_STATE_TRANSFER,	/* waiting to xfer transfer_buffer */
101 	PKT_STATE_TERMINATE	/* waiting to terminate control transfer */
102 };
103 
104 enum scheduling_pass {
105 	SCHED_PASS_PERIODIC,
106 	SCHED_PASS_NON_PERIODIC,
107 	SCHED_PASS_DONE
108 };
109 
110 /* Bit numbers for max3421_hcd->todo: */
111 enum {
112 	ENABLE_IRQ = 0,
113 	RESET_HCD,
114 	RESET_PORT,
115 	CHECK_UNLINK,
116 	IOPIN_UPDATE
117 };
118 
119 struct max3421_dma_buf {
120 	u8 data[2];
121 };
122 
123 struct max3421_hcd {
124 	spinlock_t lock;
125 
126 	struct task_struct *spi_thread;
127 
128 	struct max3421_hcd *next;
129 
130 	enum max3421_rh_state rh_state;
131 	/* lower 16 bits contain port status, upper 16 bits the change mask: */
132 	u32 port_status;
133 
134 	unsigned active:1;
135 
136 	struct list_head ep_list;	/* list of EP's with work */
137 
138 	/*
139 	 * The following are owned by spi_thread (may be accessed by
140 	 * SPI-thread without acquiring the HCD lock:
141 	 */
142 	u8 rev;				/* chip revision */
143 	u16 frame_number;
144 	/*
145 	 * kmalloc'd buffers guaranteed to be in separate (DMA)
146 	 * cache-lines:
147 	 */
148 	struct max3421_dma_buf *tx;
149 	struct max3421_dma_buf *rx;
150 	/*
151 	 * URB we're currently processing.  Must not be reset to NULL
152 	 * unless MAX3421E chip is idle:
153 	 */
154 	struct urb *curr_urb;
155 	enum scheduling_pass sched_pass;
156 	struct usb_device *loaded_dev;	/* dev that's loaded into the chip */
157 	int loaded_epnum;		/* epnum whose toggles are loaded */
158 	int urb_done;			/* > 0 -> no errors, < 0: errno */
159 	size_t curr_len;
160 	u8 hien;
161 	u8 mode;
162 	u8 iopins[2];
163 	unsigned long todo;
164 #ifdef DEBUG
165 	unsigned long err_stat[16];
166 #endif
167 };
168 
169 struct max3421_ep {
170 	struct usb_host_endpoint *ep;
171 	struct list_head ep_list;
172 	u32 naks;
173 	u16 last_active;		/* frame # this ep was last active */
174 	enum pkt_state pkt_state;
175 	u8 retries;
176 	u8 retransmit;			/* packet needs retransmission */
177 };
178 
179 static struct max3421_hcd *max3421_hcd_list;
180 
181 #define MAX3421_FIFO_SIZE	64
182 
183 #define MAX3421_SPI_DIR_RD	0	/* read register from MAX3421 */
184 #define MAX3421_SPI_DIR_WR	1	/* write register to MAX3421 */
185 
186 /* SPI commands: */
187 #define MAX3421_SPI_DIR_SHIFT	1
188 #define MAX3421_SPI_REG_SHIFT	3
189 
190 #define MAX3421_REG_RCVFIFO	1
191 #define MAX3421_REG_SNDFIFO	2
192 #define MAX3421_REG_SUDFIFO	4
193 #define MAX3421_REG_RCVBC	6
194 #define MAX3421_REG_SNDBC	7
195 #define MAX3421_REG_USBIRQ	13
196 #define MAX3421_REG_USBIEN	14
197 #define MAX3421_REG_USBCTL	15
198 #define MAX3421_REG_CPUCTL	16
199 #define MAX3421_REG_PINCTL	17
200 #define MAX3421_REG_REVISION	18
201 #define MAX3421_REG_IOPINS1	20
202 #define MAX3421_REG_IOPINS2	21
203 #define MAX3421_REG_GPINIRQ	22
204 #define MAX3421_REG_GPINIEN	23
205 #define MAX3421_REG_GPINPOL	24
206 #define MAX3421_REG_HIRQ	25
207 #define MAX3421_REG_HIEN	26
208 #define MAX3421_REG_MODE	27
209 #define MAX3421_REG_PERADDR	28
210 #define MAX3421_REG_HCTL	29
211 #define MAX3421_REG_HXFR	30
212 #define MAX3421_REG_HRSL	31
213 
214 enum {
215 	MAX3421_USBIRQ_OSCOKIRQ_BIT = 0,
216 	MAX3421_USBIRQ_NOVBUSIRQ_BIT = 5,
217 	MAX3421_USBIRQ_VBUSIRQ_BIT
218 };
219 
220 enum {
221 	MAX3421_CPUCTL_IE_BIT = 0,
222 	MAX3421_CPUCTL_PULSEWID0_BIT = 6,
223 	MAX3421_CPUCTL_PULSEWID1_BIT
224 };
225 
226 enum {
227 	MAX3421_USBCTL_PWRDOWN_BIT = 4,
228 	MAX3421_USBCTL_CHIPRES_BIT
229 };
230 
231 enum {
232 	MAX3421_PINCTL_GPXA_BIT	= 0,
233 	MAX3421_PINCTL_GPXB_BIT,
234 	MAX3421_PINCTL_POSINT_BIT,
235 	MAX3421_PINCTL_INTLEVEL_BIT,
236 	MAX3421_PINCTL_FDUPSPI_BIT,
237 	MAX3421_PINCTL_EP0INAK_BIT,
238 	MAX3421_PINCTL_EP2INAK_BIT,
239 	MAX3421_PINCTL_EP3INAK_BIT,
240 };
241 
242 enum {
243 	MAX3421_HI_BUSEVENT_BIT = 0,	/* bus-reset/-resume */
244 	MAX3421_HI_RWU_BIT,		/* remote wakeup */
245 	MAX3421_HI_RCVDAV_BIT,		/* receive FIFO data available */
246 	MAX3421_HI_SNDBAV_BIT,		/* send buffer available */
247 	MAX3421_HI_SUSDN_BIT,		/* suspend operation done */
248 	MAX3421_HI_CONDET_BIT,		/* peripheral connect/disconnect */
249 	MAX3421_HI_FRAME_BIT,		/* frame generator */
250 	MAX3421_HI_HXFRDN_BIT,		/* host transfer done */
251 };
252 
253 enum {
254 	MAX3421_HCTL_BUSRST_BIT = 0,
255 	MAX3421_HCTL_FRMRST_BIT,
256 	MAX3421_HCTL_SAMPLEBUS_BIT,
257 	MAX3421_HCTL_SIGRSM_BIT,
258 	MAX3421_HCTL_RCVTOG0_BIT,
259 	MAX3421_HCTL_RCVTOG1_BIT,
260 	MAX3421_HCTL_SNDTOG0_BIT,
261 	MAX3421_HCTL_SNDTOG1_BIT
262 };
263 
264 enum {
265 	MAX3421_MODE_HOST_BIT = 0,
266 	MAX3421_MODE_LOWSPEED_BIT,
267 	MAX3421_MODE_HUBPRE_BIT,
268 	MAX3421_MODE_SOFKAENAB_BIT,
269 	MAX3421_MODE_SEPIRQ_BIT,
270 	MAX3421_MODE_DELAYISO_BIT,
271 	MAX3421_MODE_DMPULLDN_BIT,
272 	MAX3421_MODE_DPPULLDN_BIT
273 };
274 
275 enum {
276 	MAX3421_HRSL_OK = 0,
277 	MAX3421_HRSL_BUSY,
278 	MAX3421_HRSL_BADREQ,
279 	MAX3421_HRSL_UNDEF,
280 	MAX3421_HRSL_NAK,
281 	MAX3421_HRSL_STALL,
282 	MAX3421_HRSL_TOGERR,
283 	MAX3421_HRSL_WRONGPID,
284 	MAX3421_HRSL_BADBC,
285 	MAX3421_HRSL_PIDERR,
286 	MAX3421_HRSL_PKTERR,
287 	MAX3421_HRSL_CRCERR,
288 	MAX3421_HRSL_KERR,
289 	MAX3421_HRSL_JERR,
290 	MAX3421_HRSL_TIMEOUT,
291 	MAX3421_HRSL_BABBLE,
292 	MAX3421_HRSL_RESULT_MASK = 0xf,
293 	MAX3421_HRSL_RCVTOGRD_BIT = 4,
294 	MAX3421_HRSL_SNDTOGRD_BIT,
295 	MAX3421_HRSL_KSTATUS_BIT,
296 	MAX3421_HRSL_JSTATUS_BIT
297 };
298 
299 /* Return same error-codes as ohci.h:cc_to_error: */
300 static const int hrsl_to_error[] = {
301 	[MAX3421_HRSL_OK] =		0,
302 	[MAX3421_HRSL_BUSY] =		-EINVAL,
303 	[MAX3421_HRSL_BADREQ] =		-EINVAL,
304 	[MAX3421_HRSL_UNDEF] =		-EINVAL,
305 	[MAX3421_HRSL_NAK] =		-EAGAIN,
306 	[MAX3421_HRSL_STALL] =		-EPIPE,
307 	[MAX3421_HRSL_TOGERR] =		-EILSEQ,
308 	[MAX3421_HRSL_WRONGPID] =	-EPROTO,
309 	[MAX3421_HRSL_BADBC] =		-EREMOTEIO,
310 	[MAX3421_HRSL_PIDERR] =		-EPROTO,
311 	[MAX3421_HRSL_PKTERR] =		-EPROTO,
312 	[MAX3421_HRSL_CRCERR] =		-EILSEQ,
313 	[MAX3421_HRSL_KERR] =		-EIO,
314 	[MAX3421_HRSL_JERR] =		-EIO,
315 	[MAX3421_HRSL_TIMEOUT] =	-ETIME,
316 	[MAX3421_HRSL_BABBLE] =		-EOVERFLOW
317 };
318 
319 /*
320  * See https://www.beyondlogic.org/usbnutshell/usb4.shtml#Control for a
321  * reasonable overview of how control transfers use the the IN/OUT
322  * tokens.
323  */
324 #define MAX3421_HXFR_BULK_IN(ep)	(0x00 | (ep))	/* bulk or interrupt */
325 #define MAX3421_HXFR_SETUP		 0x10
326 #define MAX3421_HXFR_BULK_OUT(ep)	(0x20 | (ep))	/* bulk or interrupt */
327 #define MAX3421_HXFR_ISO_IN(ep)		(0x40 | (ep))
328 #define MAX3421_HXFR_ISO_OUT(ep)	(0x60 | (ep))
329 #define MAX3421_HXFR_HS_IN		 0x80		/* handshake in */
330 #define MAX3421_HXFR_HS_OUT		 0xa0		/* handshake out */
331 
332 #define field(val, bit)	((val) << (bit))
333 
334 static inline s16
335 frame_diff(u16 left, u16 right)
336 {
337 	return ((unsigned) (left - right)) % (USB_MAX_FRAME_NUMBER + 1);
338 }
339 
340 static inline struct max3421_hcd *
341 hcd_to_max3421(struct usb_hcd *hcd)
342 {
343 	return (struct max3421_hcd *) hcd->hcd_priv;
344 }
345 
346 static inline struct usb_hcd *
347 max3421_to_hcd(struct max3421_hcd *max3421_hcd)
348 {
349 	return container_of((void *) max3421_hcd, struct usb_hcd, hcd_priv);
350 }
351 
352 static u8
353 spi_rd8(struct usb_hcd *hcd, unsigned int reg)
354 {
355 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
356 	struct spi_device *spi = to_spi_device(hcd->self.controller);
357 	struct spi_transfer transfer;
358 	struct spi_message msg;
359 
360 	memset(&transfer, 0, sizeof(transfer));
361 
362 	spi_message_init(&msg);
363 
364 	max3421_hcd->tx->data[0] =
365 		(field(reg, MAX3421_SPI_REG_SHIFT) |
366 		 field(MAX3421_SPI_DIR_RD, MAX3421_SPI_DIR_SHIFT));
367 
368 	transfer.tx_buf = max3421_hcd->tx->data;
369 	transfer.rx_buf = max3421_hcd->rx->data;
370 	transfer.len = 2;
371 
372 	spi_message_add_tail(&transfer, &msg);
373 	spi_sync(spi, &msg);
374 
375 	return max3421_hcd->rx->data[1];
376 }
377 
378 static void
379 spi_wr8(struct usb_hcd *hcd, unsigned int reg, u8 val)
380 {
381 	struct spi_device *spi = to_spi_device(hcd->self.controller);
382 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
383 	struct spi_transfer transfer;
384 	struct spi_message msg;
385 
386 	memset(&transfer, 0, sizeof(transfer));
387 
388 	spi_message_init(&msg);
389 
390 	max3421_hcd->tx->data[0] =
391 		(field(reg, MAX3421_SPI_REG_SHIFT) |
392 		 field(MAX3421_SPI_DIR_WR, MAX3421_SPI_DIR_SHIFT));
393 	max3421_hcd->tx->data[1] = val;
394 
395 	transfer.tx_buf = max3421_hcd->tx->data;
396 	transfer.len = 2;
397 
398 	spi_message_add_tail(&transfer, &msg);
399 	spi_sync(spi, &msg);
400 }
401 
402 static void
403 spi_rd_buf(struct usb_hcd *hcd, unsigned int reg, void *buf, size_t len)
404 {
405 	struct spi_device *spi = to_spi_device(hcd->self.controller);
406 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
407 	struct spi_transfer transfer[2];
408 	struct spi_message msg;
409 
410 	memset(transfer, 0, sizeof(transfer));
411 
412 	spi_message_init(&msg);
413 
414 	max3421_hcd->tx->data[0] =
415 		(field(reg, MAX3421_SPI_REG_SHIFT) |
416 		 field(MAX3421_SPI_DIR_RD, MAX3421_SPI_DIR_SHIFT));
417 	transfer[0].tx_buf = max3421_hcd->tx->data;
418 	transfer[0].len = 1;
419 
420 	transfer[1].rx_buf = buf;
421 	transfer[1].len = len;
422 
423 	spi_message_add_tail(&transfer[0], &msg);
424 	spi_message_add_tail(&transfer[1], &msg);
425 	spi_sync(spi, &msg);
426 }
427 
428 static void
429 spi_wr_buf(struct usb_hcd *hcd, unsigned int reg, void *buf, size_t len)
430 {
431 	struct spi_device *spi = to_spi_device(hcd->self.controller);
432 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
433 	struct spi_transfer transfer[2];
434 	struct spi_message msg;
435 
436 	memset(transfer, 0, sizeof(transfer));
437 
438 	spi_message_init(&msg);
439 
440 	max3421_hcd->tx->data[0] =
441 		(field(reg, MAX3421_SPI_REG_SHIFT) |
442 		 field(MAX3421_SPI_DIR_WR, MAX3421_SPI_DIR_SHIFT));
443 
444 	transfer[0].tx_buf = max3421_hcd->tx->data;
445 	transfer[0].len = 1;
446 
447 	transfer[1].tx_buf = buf;
448 	transfer[1].len = len;
449 
450 	spi_message_add_tail(&transfer[0], &msg);
451 	spi_message_add_tail(&transfer[1], &msg);
452 	spi_sync(spi, &msg);
453 }
454 
455 /*
456  * Figure out the correct setting for the LOWSPEED and HUBPRE mode
457  * bits.  The HUBPRE bit needs to be set when MAX3421E operates at
458  * full speed, but it's talking to a low-speed device (i.e., through a
459  * hub).  Setting that bit ensures that every low-speed packet is
460  * preceded by a full-speed PRE PID.  Possible configurations:
461  *
462  * Hub speed:	Device speed:	=>	LOWSPEED bit:	HUBPRE bit:
463  *	FULL	FULL		=>	0		0
464  *	FULL	LOW		=>	1		1
465  *	LOW	LOW		=>	1		0
466  *	LOW	FULL		=>	1		0
467  */
468 static void
469 max3421_set_speed(struct usb_hcd *hcd, struct usb_device *dev)
470 {
471 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
472 	u8 mode_lowspeed, mode_hubpre, mode = max3421_hcd->mode;
473 
474 	mode_lowspeed = BIT(MAX3421_MODE_LOWSPEED_BIT);
475 	mode_hubpre   = BIT(MAX3421_MODE_HUBPRE_BIT);
476 	if (max3421_hcd->port_status & USB_PORT_STAT_LOW_SPEED) {
477 		mode |=  mode_lowspeed;
478 		mode &= ~mode_hubpre;
479 	} else if (dev->speed == USB_SPEED_LOW) {
480 		mode |= mode_lowspeed | mode_hubpre;
481 	} else {
482 		mode &= ~(mode_lowspeed | mode_hubpre);
483 	}
484 	if (mode != max3421_hcd->mode) {
485 		max3421_hcd->mode = mode;
486 		spi_wr8(hcd, MAX3421_REG_MODE, max3421_hcd->mode);
487 	}
488 
489 }
490 
491 /*
492  * Caller must NOT hold HCD spinlock.
493  */
494 static void
495 max3421_set_address(struct usb_hcd *hcd, struct usb_device *dev, int epnum,
496 		    int force_toggles)
497 {
498 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
499 	int old_epnum, same_ep, rcvtog, sndtog;
500 	struct usb_device *old_dev;
501 	u8 hctl;
502 
503 	old_dev = max3421_hcd->loaded_dev;
504 	old_epnum = max3421_hcd->loaded_epnum;
505 
506 	same_ep = (dev == old_dev && epnum == old_epnum);
507 	if (same_ep && !force_toggles)
508 		return;
509 
510 	if (old_dev && !same_ep) {
511 		/* save the old end-points toggles: */
512 		u8 hrsl = spi_rd8(hcd, MAX3421_REG_HRSL);
513 
514 		rcvtog = (hrsl >> MAX3421_HRSL_RCVTOGRD_BIT) & 1;
515 		sndtog = (hrsl >> MAX3421_HRSL_SNDTOGRD_BIT) & 1;
516 
517 		/* no locking: HCD (i.e., we) own toggles, don't we? */
518 		usb_settoggle(old_dev, old_epnum, 0, rcvtog);
519 		usb_settoggle(old_dev, old_epnum, 1, sndtog);
520 	}
521 	/* setup new endpoint's toggle bits: */
522 	rcvtog = usb_gettoggle(dev, epnum, 0);
523 	sndtog = usb_gettoggle(dev, epnum, 1);
524 	hctl = (BIT(rcvtog + MAX3421_HCTL_RCVTOG0_BIT) |
525 		BIT(sndtog + MAX3421_HCTL_SNDTOG0_BIT));
526 
527 	max3421_hcd->loaded_epnum = epnum;
528 	spi_wr8(hcd, MAX3421_REG_HCTL, hctl);
529 
530 	/*
531 	 * Note: devnum for one and the same device can change during
532 	 * address-assignment so it's best to just always load the
533 	 * address whenever the end-point changed/was forced.
534 	 */
535 	max3421_hcd->loaded_dev = dev;
536 	spi_wr8(hcd, MAX3421_REG_PERADDR, dev->devnum);
537 }
538 
539 static int
540 max3421_ctrl_setup(struct usb_hcd *hcd, struct urb *urb)
541 {
542 	spi_wr_buf(hcd, MAX3421_REG_SUDFIFO, urb->setup_packet, 8);
543 	return MAX3421_HXFR_SETUP;
544 }
545 
546 static int
547 max3421_transfer_in(struct usb_hcd *hcd, struct urb *urb)
548 {
549 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
550 	int epnum = usb_pipeendpoint(urb->pipe);
551 
552 	max3421_hcd->curr_len = 0;
553 	max3421_hcd->hien |= BIT(MAX3421_HI_RCVDAV_BIT);
554 	return MAX3421_HXFR_BULK_IN(epnum);
555 }
556 
557 static int
558 max3421_transfer_out(struct usb_hcd *hcd, struct urb *urb, int fast_retransmit)
559 {
560 	struct spi_device *spi = to_spi_device(hcd->self.controller);
561 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
562 	int epnum = usb_pipeendpoint(urb->pipe);
563 	u32 max_packet;
564 	void *src;
565 
566 	src = urb->transfer_buffer + urb->actual_length;
567 
568 	if (fast_retransmit) {
569 		if (max3421_hcd->rev == 0x12) {
570 			/* work around rev 0x12 bug: */
571 			spi_wr8(hcd, MAX3421_REG_SNDBC, 0);
572 			spi_wr8(hcd, MAX3421_REG_SNDFIFO, ((u8 *) src)[0]);
573 			spi_wr8(hcd, MAX3421_REG_SNDBC, max3421_hcd->curr_len);
574 		}
575 		return MAX3421_HXFR_BULK_OUT(epnum);
576 	}
577 
578 	max_packet = usb_maxpacket(urb->dev, urb->pipe, 1);
579 
580 	if (max_packet > MAX3421_FIFO_SIZE) {
581 		/*
582 		 * We do not support isochronous transfers at this
583 		 * time.
584 		 */
585 		dev_err(&spi->dev,
586 			"%s: packet-size of %u too big (limit is %u bytes)",
587 			__func__, max_packet, MAX3421_FIFO_SIZE);
588 		max3421_hcd->urb_done = -EMSGSIZE;
589 		return -EMSGSIZE;
590 	}
591 	max3421_hcd->curr_len = min((urb->transfer_buffer_length -
592 				     urb->actual_length), max_packet);
593 
594 	spi_wr_buf(hcd, MAX3421_REG_SNDFIFO, src, max3421_hcd->curr_len);
595 	spi_wr8(hcd, MAX3421_REG_SNDBC, max3421_hcd->curr_len);
596 	return MAX3421_HXFR_BULK_OUT(epnum);
597 }
598 
599 /*
600  * Issue the next host-transfer command.
601  * Caller must NOT hold HCD spinlock.
602  */
603 static void
604 max3421_next_transfer(struct usb_hcd *hcd, int fast_retransmit)
605 {
606 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
607 	struct urb *urb = max3421_hcd->curr_urb;
608 	struct max3421_ep *max3421_ep;
609 	int cmd = -EINVAL;
610 
611 	if (!urb)
612 		return;	/* nothing to do */
613 
614 	max3421_ep = urb->ep->hcpriv;
615 
616 	switch (max3421_ep->pkt_state) {
617 	case PKT_STATE_SETUP:
618 		cmd = max3421_ctrl_setup(hcd, urb);
619 		break;
620 
621 	case PKT_STATE_TRANSFER:
622 		if (usb_urb_dir_in(urb))
623 			cmd = max3421_transfer_in(hcd, urb);
624 		else
625 			cmd = max3421_transfer_out(hcd, urb, fast_retransmit);
626 		break;
627 
628 	case PKT_STATE_TERMINATE:
629 		/*
630 		 * IN transfers are terminated with HS_OUT token,
631 		 * OUT transfers with HS_IN:
632 		 */
633 		if (usb_urb_dir_in(urb))
634 			cmd = MAX3421_HXFR_HS_OUT;
635 		else
636 			cmd = MAX3421_HXFR_HS_IN;
637 		break;
638 	}
639 
640 	if (cmd < 0)
641 		return;
642 
643 	/* issue the command and wait for host-xfer-done interrupt: */
644 
645 	spi_wr8(hcd, MAX3421_REG_HXFR, cmd);
646 	max3421_hcd->hien |= BIT(MAX3421_HI_HXFRDN_BIT);
647 }
648 
649 /*
650  * Find the next URB to process and start its execution.
651  *
652  * At this time, we do not anticipate ever connecting a USB hub to the
653  * MAX3421 chip, so at most USB device can be connected and we can use
654  * a simplistic scheduler: at the start of a frame, schedule all
655  * periodic transfers.  Once that is done, use the remainder of the
656  * frame to process non-periodic (bulk & control) transfers.
657  *
658  * Preconditions:
659  * o Caller must NOT hold HCD spinlock.
660  * o max3421_hcd->curr_urb MUST BE NULL.
661  * o MAX3421E chip must be idle.
662  */
663 static int
664 max3421_select_and_start_urb(struct usb_hcd *hcd)
665 {
666 	struct spi_device *spi = to_spi_device(hcd->self.controller);
667 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
668 	struct urb *urb, *curr_urb = NULL;
669 	struct max3421_ep *max3421_ep;
670 	int epnum, force_toggles = 0;
671 	struct usb_host_endpoint *ep;
672 	struct list_head *pos;
673 	unsigned long flags;
674 
675 	spin_lock_irqsave(&max3421_hcd->lock, flags);
676 
677 	for (;
678 	     max3421_hcd->sched_pass < SCHED_PASS_DONE;
679 	     ++max3421_hcd->sched_pass)
680 		list_for_each(pos, &max3421_hcd->ep_list) {
681 			urb = NULL;
682 			max3421_ep = container_of(pos, struct max3421_ep,
683 						  ep_list);
684 			ep = max3421_ep->ep;
685 
686 			switch (usb_endpoint_type(&ep->desc)) {
687 			case USB_ENDPOINT_XFER_ISOC:
688 			case USB_ENDPOINT_XFER_INT:
689 				if (max3421_hcd->sched_pass !=
690 				    SCHED_PASS_PERIODIC)
691 					continue;
692 				break;
693 
694 			case USB_ENDPOINT_XFER_CONTROL:
695 			case USB_ENDPOINT_XFER_BULK:
696 				if (max3421_hcd->sched_pass !=
697 				    SCHED_PASS_NON_PERIODIC)
698 					continue;
699 				break;
700 			}
701 
702 			if (list_empty(&ep->urb_list))
703 				continue;	/* nothing to do */
704 			urb = list_first_entry(&ep->urb_list, struct urb,
705 					       urb_list);
706 			if (urb->unlinked) {
707 				dev_dbg(&spi->dev, "%s: URB %p unlinked=%d",
708 					__func__, urb, urb->unlinked);
709 				max3421_hcd->curr_urb = urb;
710 				max3421_hcd->urb_done = 1;
711 				spin_unlock_irqrestore(&max3421_hcd->lock,
712 						       flags);
713 				return 1;
714 			}
715 
716 			switch (usb_endpoint_type(&ep->desc)) {
717 			case USB_ENDPOINT_XFER_CONTROL:
718 				/*
719 				 * Allow one control transaction per
720 				 * frame per endpoint:
721 				 */
722 				if (frame_diff(max3421_ep->last_active,
723 					       max3421_hcd->frame_number) == 0)
724 					continue;
725 				break;
726 
727 			case USB_ENDPOINT_XFER_BULK:
728 				if (max3421_ep->retransmit
729 				    && (frame_diff(max3421_ep->last_active,
730 						   max3421_hcd->frame_number)
731 					== 0))
732 					/*
733 					 * We already tried this EP
734 					 * during this frame and got a
735 					 * NAK or error; wait for next frame
736 					 */
737 					continue;
738 				break;
739 
740 			case USB_ENDPOINT_XFER_ISOC:
741 			case USB_ENDPOINT_XFER_INT:
742 				if (frame_diff(max3421_hcd->frame_number,
743 					       max3421_ep->last_active)
744 				    < urb->interval)
745 					/*
746 					 * We already processed this
747 					 * end-point in the current
748 					 * frame
749 					 */
750 					continue;
751 				break;
752 			}
753 
754 			/* move current ep to tail: */
755 			list_move_tail(pos, &max3421_hcd->ep_list);
756 			curr_urb = urb;
757 			goto done;
758 		}
759 done:
760 	if (!curr_urb) {
761 		spin_unlock_irqrestore(&max3421_hcd->lock, flags);
762 		return 0;
763 	}
764 
765 	urb = max3421_hcd->curr_urb = curr_urb;
766 	epnum = usb_endpoint_num(&urb->ep->desc);
767 	if (max3421_ep->retransmit)
768 		/* restart (part of) a USB transaction: */
769 		max3421_ep->retransmit = 0;
770 	else {
771 		/* start USB transaction: */
772 		if (usb_endpoint_xfer_control(&ep->desc)) {
773 			/*
774 			 * See USB 2.0 spec section 8.6.1
775 			 * Initialization via SETUP Token:
776 			 */
777 			usb_settoggle(urb->dev, epnum, 0, 1);
778 			usb_settoggle(urb->dev, epnum, 1, 1);
779 			max3421_ep->pkt_state = PKT_STATE_SETUP;
780 			force_toggles = 1;
781 		} else
782 			max3421_ep->pkt_state = PKT_STATE_TRANSFER;
783 	}
784 
785 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
786 
787 	max3421_ep->last_active = max3421_hcd->frame_number;
788 	max3421_set_address(hcd, urb->dev, epnum, force_toggles);
789 	max3421_set_speed(hcd, urb->dev);
790 	max3421_next_transfer(hcd, 0);
791 	return 1;
792 }
793 
794 /*
795  * Check all endpoints for URBs that got unlinked.
796  *
797  * Caller must NOT hold HCD spinlock.
798  */
799 static int
800 max3421_check_unlink(struct usb_hcd *hcd)
801 {
802 	struct spi_device *spi = to_spi_device(hcd->self.controller);
803 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
804 	struct max3421_ep *max3421_ep;
805 	struct usb_host_endpoint *ep;
806 	struct urb *urb, *next;
807 	unsigned long flags;
808 	int retval = 0;
809 
810 	spin_lock_irqsave(&max3421_hcd->lock, flags);
811 	list_for_each_entry(max3421_ep, &max3421_hcd->ep_list, ep_list) {
812 		ep = max3421_ep->ep;
813 		list_for_each_entry_safe(urb, next, &ep->urb_list, urb_list) {
814 			if (urb->unlinked) {
815 				retval = 1;
816 				dev_dbg(&spi->dev, "%s: URB %p unlinked=%d",
817 					__func__, urb, urb->unlinked);
818 				usb_hcd_unlink_urb_from_ep(hcd, urb);
819 				spin_unlock_irqrestore(&max3421_hcd->lock,
820 						       flags);
821 				usb_hcd_giveback_urb(hcd, urb, 0);
822 				spin_lock_irqsave(&max3421_hcd->lock, flags);
823 			}
824 		}
825 	}
826 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
827 	return retval;
828 }
829 
830 /*
831  * Caller must NOT hold HCD spinlock.
832  */
833 static void
834 max3421_slow_retransmit(struct usb_hcd *hcd)
835 {
836 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
837 	struct urb *urb = max3421_hcd->curr_urb;
838 	struct max3421_ep *max3421_ep;
839 
840 	max3421_ep = urb->ep->hcpriv;
841 	max3421_ep->retransmit = 1;
842 	max3421_hcd->curr_urb = NULL;
843 }
844 
845 /*
846  * Caller must NOT hold HCD spinlock.
847  */
848 static void
849 max3421_recv_data_available(struct usb_hcd *hcd)
850 {
851 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
852 	struct urb *urb = max3421_hcd->curr_urb;
853 	size_t remaining, transfer_size;
854 	u8 rcvbc;
855 
856 	rcvbc = spi_rd8(hcd, MAX3421_REG_RCVBC);
857 
858 	if (rcvbc > MAX3421_FIFO_SIZE)
859 		rcvbc = MAX3421_FIFO_SIZE;
860 	if (urb->actual_length >= urb->transfer_buffer_length)
861 		remaining = 0;
862 	else
863 		remaining = urb->transfer_buffer_length - urb->actual_length;
864 	transfer_size = rcvbc;
865 	if (transfer_size > remaining)
866 		transfer_size = remaining;
867 	if (transfer_size > 0) {
868 		void *dst = urb->transfer_buffer + urb->actual_length;
869 
870 		spi_rd_buf(hcd, MAX3421_REG_RCVFIFO, dst, transfer_size);
871 		urb->actual_length += transfer_size;
872 		max3421_hcd->curr_len = transfer_size;
873 	}
874 
875 	/* ack the RCVDAV irq now that the FIFO has been read: */
876 	spi_wr8(hcd, MAX3421_REG_HIRQ, BIT(MAX3421_HI_RCVDAV_BIT));
877 }
878 
879 static void
880 max3421_handle_error(struct usb_hcd *hcd, u8 hrsl)
881 {
882 	struct spi_device *spi = to_spi_device(hcd->self.controller);
883 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
884 	u8 result_code = hrsl & MAX3421_HRSL_RESULT_MASK;
885 	struct urb *urb = max3421_hcd->curr_urb;
886 	struct max3421_ep *max3421_ep = urb->ep->hcpriv;
887 	int switch_sndfifo;
888 
889 	/*
890 	 * If an OUT command results in any response other than OK
891 	 * (i.e., error or NAK), we have to perform a dummy-write to
892 	 * SNDBC so the FIFO gets switched back to us.  Otherwise, we
893 	 * get out of sync with the SNDFIFO double buffer.
894 	 */
895 	switch_sndfifo = (max3421_ep->pkt_state == PKT_STATE_TRANSFER &&
896 			  usb_urb_dir_out(urb));
897 
898 	switch (result_code) {
899 	case MAX3421_HRSL_OK:
900 		return;			/* this shouldn't happen */
901 
902 	case MAX3421_HRSL_WRONGPID:	/* received wrong PID */
903 	case MAX3421_HRSL_BUSY:		/* SIE busy */
904 	case MAX3421_HRSL_BADREQ:	/* bad val in HXFR */
905 	case MAX3421_HRSL_UNDEF:	/* reserved */
906 	case MAX3421_HRSL_KERR:		/* K-state instead of response */
907 	case MAX3421_HRSL_JERR:		/* J-state instead of response */
908 		/*
909 		 * packet experienced an error that we cannot recover
910 		 * from; report error
911 		 */
912 		max3421_hcd->urb_done = hrsl_to_error[result_code];
913 		dev_dbg(&spi->dev, "%s: unexpected error HRSL=0x%02x",
914 			__func__, hrsl);
915 		break;
916 
917 	case MAX3421_HRSL_TOGERR:
918 		if (usb_urb_dir_in(urb))
919 			; /* don't do anything (device will switch toggle) */
920 		else {
921 			/* flip the send toggle bit: */
922 			int sndtog = (hrsl >> MAX3421_HRSL_SNDTOGRD_BIT) & 1;
923 
924 			sndtog ^= 1;
925 			spi_wr8(hcd, MAX3421_REG_HCTL,
926 				BIT(sndtog + MAX3421_HCTL_SNDTOG0_BIT));
927 		}
928 		fallthrough;
929 	case MAX3421_HRSL_BADBC:	/* bad byte count */
930 	case MAX3421_HRSL_PIDERR:	/* received PID is corrupted */
931 	case MAX3421_HRSL_PKTERR:	/* packet error (stuff, EOP) */
932 	case MAX3421_HRSL_CRCERR:	/* CRC error */
933 	case MAX3421_HRSL_BABBLE:	/* device talked too long */
934 	case MAX3421_HRSL_TIMEOUT:
935 		if (max3421_ep->retries++ < USB_MAX_RETRIES)
936 			/* retry the packet again in the next frame */
937 			max3421_slow_retransmit(hcd);
938 		else {
939 			/* Based on ohci.h cc_to_err[]: */
940 			max3421_hcd->urb_done = hrsl_to_error[result_code];
941 			dev_dbg(&spi->dev, "%s: unexpected error HRSL=0x%02x",
942 				__func__, hrsl);
943 		}
944 		break;
945 
946 	case MAX3421_HRSL_STALL:
947 		dev_dbg(&spi->dev, "%s: unexpected error HRSL=0x%02x",
948 			__func__, hrsl);
949 		max3421_hcd->urb_done = hrsl_to_error[result_code];
950 		break;
951 
952 	case MAX3421_HRSL_NAK:
953 		/*
954 		 * Device wasn't ready for data or has no data
955 		 * available: retry the packet again.
956 		 */
957 		if (max3421_ep->naks++ < NAK_MAX_FAST_RETRANSMITS) {
958 			max3421_next_transfer(hcd, 1);
959 			switch_sndfifo = 0;
960 		} else
961 			max3421_slow_retransmit(hcd);
962 		break;
963 	}
964 	if (switch_sndfifo)
965 		spi_wr8(hcd, MAX3421_REG_SNDBC, 0);
966 }
967 
968 /*
969  * Caller must NOT hold HCD spinlock.
970  */
971 static int
972 max3421_transfer_in_done(struct usb_hcd *hcd, struct urb *urb)
973 {
974 	struct spi_device *spi = to_spi_device(hcd->self.controller);
975 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
976 	u32 max_packet;
977 
978 	if (urb->actual_length >= urb->transfer_buffer_length)
979 		return 1;	/* read is complete, so we're done */
980 
981 	/*
982 	 * USB 2.0 Section 5.3.2 Pipes: packets must be full size
983 	 * except for last one.
984 	 */
985 	max_packet = usb_maxpacket(urb->dev, urb->pipe, 0);
986 	if (max_packet > MAX3421_FIFO_SIZE) {
987 		/*
988 		 * We do not support isochronous transfers at this
989 		 * time...
990 		 */
991 		dev_err(&spi->dev,
992 			"%s: packet-size of %u too big (limit is %u bytes)",
993 			__func__, max_packet, MAX3421_FIFO_SIZE);
994 		return -EINVAL;
995 	}
996 
997 	if (max3421_hcd->curr_len < max_packet) {
998 		if (urb->transfer_flags & URB_SHORT_NOT_OK) {
999 			/*
1000 			 * remaining > 0 and received an
1001 			 * unexpected partial packet ->
1002 			 * error
1003 			 */
1004 			return -EREMOTEIO;
1005 		} else
1006 			/* short read, but it's OK */
1007 			return 1;
1008 	}
1009 	return 0;	/* not done */
1010 }
1011 
1012 /*
1013  * Caller must NOT hold HCD spinlock.
1014  */
1015 static int
1016 max3421_transfer_out_done(struct usb_hcd *hcd, struct urb *urb)
1017 {
1018 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1019 
1020 	urb->actual_length += max3421_hcd->curr_len;
1021 	if (urb->actual_length < urb->transfer_buffer_length)
1022 		return 0;
1023 	if (urb->transfer_flags & URB_ZERO_PACKET) {
1024 		/*
1025 		 * Some hardware needs a zero-size packet at the end
1026 		 * of a bulk-out transfer if the last transfer was a
1027 		 * full-sized packet (i.e., such hardware use <
1028 		 * max_packet as an indicator that the end of the
1029 		 * packet has been reached).
1030 		 */
1031 		u32 max_packet = usb_maxpacket(urb->dev, urb->pipe, 1);
1032 
1033 		if (max3421_hcd->curr_len == max_packet)
1034 			return 0;
1035 	}
1036 	return 1;
1037 }
1038 
1039 /*
1040  * Caller must NOT hold HCD spinlock.
1041  */
1042 static void
1043 max3421_host_transfer_done(struct usb_hcd *hcd)
1044 {
1045 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1046 	struct urb *urb = max3421_hcd->curr_urb;
1047 	struct max3421_ep *max3421_ep;
1048 	u8 result_code, hrsl;
1049 	int urb_done = 0;
1050 
1051 	max3421_hcd->hien &= ~(BIT(MAX3421_HI_HXFRDN_BIT) |
1052 			       BIT(MAX3421_HI_RCVDAV_BIT));
1053 
1054 	hrsl = spi_rd8(hcd, MAX3421_REG_HRSL);
1055 	result_code = hrsl & MAX3421_HRSL_RESULT_MASK;
1056 
1057 #ifdef DEBUG
1058 	++max3421_hcd->err_stat[result_code];
1059 #endif
1060 
1061 	max3421_ep = urb->ep->hcpriv;
1062 
1063 	if (unlikely(result_code != MAX3421_HRSL_OK)) {
1064 		max3421_handle_error(hcd, hrsl);
1065 		return;
1066 	}
1067 
1068 	max3421_ep->naks = 0;
1069 	max3421_ep->retries = 0;
1070 	switch (max3421_ep->pkt_state) {
1071 
1072 	case PKT_STATE_SETUP:
1073 		if (urb->transfer_buffer_length > 0)
1074 			max3421_ep->pkt_state = PKT_STATE_TRANSFER;
1075 		else
1076 			max3421_ep->pkt_state = PKT_STATE_TERMINATE;
1077 		break;
1078 
1079 	case PKT_STATE_TRANSFER:
1080 		if (usb_urb_dir_in(urb))
1081 			urb_done = max3421_transfer_in_done(hcd, urb);
1082 		else
1083 			urb_done = max3421_transfer_out_done(hcd, urb);
1084 		if (urb_done > 0 && usb_pipetype(urb->pipe) == PIPE_CONTROL) {
1085 			/*
1086 			 * We aren't really done - we still need to
1087 			 * terminate the control transfer:
1088 			 */
1089 			max3421_hcd->urb_done = urb_done = 0;
1090 			max3421_ep->pkt_state = PKT_STATE_TERMINATE;
1091 		}
1092 		break;
1093 
1094 	case PKT_STATE_TERMINATE:
1095 		urb_done = 1;
1096 		break;
1097 	}
1098 
1099 	if (urb_done)
1100 		max3421_hcd->urb_done = urb_done;
1101 	else
1102 		max3421_next_transfer(hcd, 0);
1103 }
1104 
1105 /*
1106  * Caller must NOT hold HCD spinlock.
1107  */
1108 static void
1109 max3421_detect_conn(struct usb_hcd *hcd)
1110 {
1111 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1112 	unsigned int jk, have_conn = 0;
1113 	u32 old_port_status, chg;
1114 	unsigned long flags;
1115 	u8 hrsl, mode;
1116 
1117 	hrsl = spi_rd8(hcd, MAX3421_REG_HRSL);
1118 
1119 	jk = ((((hrsl >> MAX3421_HRSL_JSTATUS_BIT) & 1) << 0) |
1120 	      (((hrsl >> MAX3421_HRSL_KSTATUS_BIT) & 1) << 1));
1121 
1122 	mode = max3421_hcd->mode;
1123 
1124 	switch (jk) {
1125 	case 0x0: /* SE0: disconnect */
1126 		/*
1127 		 * Turn off SOFKAENAB bit to avoid getting interrupt
1128 		 * every milli-second:
1129 		 */
1130 		mode &= ~BIT(MAX3421_MODE_SOFKAENAB_BIT);
1131 		break;
1132 
1133 	case 0x1: /* J=0,K=1: low-speed (in full-speed or vice versa) */
1134 	case 0x2: /* J=1,K=0: full-speed (in full-speed or vice versa) */
1135 		if (jk == 0x2)
1136 			/* need to switch to the other speed: */
1137 			mode ^= BIT(MAX3421_MODE_LOWSPEED_BIT);
1138 		/* turn on SOFKAENAB bit: */
1139 		mode |= BIT(MAX3421_MODE_SOFKAENAB_BIT);
1140 		have_conn = 1;
1141 		break;
1142 
1143 	case 0x3: /* illegal */
1144 		break;
1145 	}
1146 
1147 	max3421_hcd->mode = mode;
1148 	spi_wr8(hcd, MAX3421_REG_MODE, max3421_hcd->mode);
1149 
1150 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1151 	old_port_status = max3421_hcd->port_status;
1152 	if (have_conn)
1153 		max3421_hcd->port_status |=  USB_PORT_STAT_CONNECTION;
1154 	else
1155 		max3421_hcd->port_status &= ~USB_PORT_STAT_CONNECTION;
1156 	if (mode & BIT(MAX3421_MODE_LOWSPEED_BIT))
1157 		max3421_hcd->port_status |=  USB_PORT_STAT_LOW_SPEED;
1158 	else
1159 		max3421_hcd->port_status &= ~USB_PORT_STAT_LOW_SPEED;
1160 	chg = (old_port_status ^ max3421_hcd->port_status);
1161 	max3421_hcd->port_status |= chg << 16;
1162 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1163 }
1164 
1165 static irqreturn_t
1166 max3421_irq_handler(int irq, void *dev_id)
1167 {
1168 	struct usb_hcd *hcd = dev_id;
1169 	struct spi_device *spi = to_spi_device(hcd->self.controller);
1170 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1171 
1172 	if (max3421_hcd->spi_thread &&
1173 	    max3421_hcd->spi_thread->state != TASK_RUNNING)
1174 		wake_up_process(max3421_hcd->spi_thread);
1175 	if (!test_and_set_bit(ENABLE_IRQ, &max3421_hcd->todo))
1176 		disable_irq_nosync(spi->irq);
1177 	return IRQ_HANDLED;
1178 }
1179 
1180 #ifdef DEBUG
1181 
1182 static void
1183 dump_eps(struct usb_hcd *hcd)
1184 {
1185 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1186 	struct max3421_ep *max3421_ep;
1187 	struct usb_host_endpoint *ep;
1188 	char ubuf[512], *dp, *end;
1189 	unsigned long flags;
1190 	struct urb *urb;
1191 	int epnum, ret;
1192 
1193 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1194 	list_for_each_entry(max3421_ep, &max3421_hcd->ep_list, ep_list) {
1195 		ep = max3421_ep->ep;
1196 
1197 		dp = ubuf;
1198 		end = dp + sizeof(ubuf);
1199 		*dp = '\0';
1200 		list_for_each_entry(urb, &ep->urb_list, urb_list) {
1201 			ret = snprintf(dp, end - dp, " %p(%d.%s %d/%d)", urb,
1202 				       usb_pipetype(urb->pipe),
1203 				       usb_urb_dir_in(urb) ? "IN" : "OUT",
1204 				       urb->actual_length,
1205 				       urb->transfer_buffer_length);
1206 			if (ret < 0 || ret >= end - dp)
1207 				break;	/* error or buffer full */
1208 			dp += ret;
1209 		}
1210 
1211 		epnum = usb_endpoint_num(&ep->desc);
1212 		pr_info("EP%0u %u lst %04u rtr %u nak %6u rxmt %u: %s\n",
1213 			epnum, max3421_ep->pkt_state, max3421_ep->last_active,
1214 			max3421_ep->retries, max3421_ep->naks,
1215 			max3421_ep->retransmit, ubuf);
1216 	}
1217 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1218 }
1219 
1220 #endif /* DEBUG */
1221 
1222 /* Return zero if no work was performed, 1 otherwise.  */
1223 static int
1224 max3421_handle_irqs(struct usb_hcd *hcd)
1225 {
1226 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1227 	u32 chg, old_port_status;
1228 	unsigned long flags;
1229 	u8 hirq;
1230 
1231 	/*
1232 	 * Read and ack pending interrupts (CPU must never
1233 	 * clear SNDBAV directly and RCVDAV must be cleared by
1234 	 * max3421_recv_data_available()!):
1235 	 */
1236 	hirq = spi_rd8(hcd, MAX3421_REG_HIRQ);
1237 	hirq &= max3421_hcd->hien;
1238 	if (!hirq)
1239 		return 0;
1240 
1241 	spi_wr8(hcd, MAX3421_REG_HIRQ,
1242 		hirq & ~(BIT(MAX3421_HI_SNDBAV_BIT) |
1243 			 BIT(MAX3421_HI_RCVDAV_BIT)));
1244 
1245 	if (hirq & BIT(MAX3421_HI_FRAME_BIT)) {
1246 		max3421_hcd->frame_number = ((max3421_hcd->frame_number + 1)
1247 					     & USB_MAX_FRAME_NUMBER);
1248 		max3421_hcd->sched_pass = SCHED_PASS_PERIODIC;
1249 	}
1250 
1251 	if (hirq & BIT(MAX3421_HI_RCVDAV_BIT))
1252 		max3421_recv_data_available(hcd);
1253 
1254 	if (hirq & BIT(MAX3421_HI_HXFRDN_BIT))
1255 		max3421_host_transfer_done(hcd);
1256 
1257 	if (hirq & BIT(MAX3421_HI_CONDET_BIT))
1258 		max3421_detect_conn(hcd);
1259 
1260 	/*
1261 	 * Now process interrupts that may affect HCD state
1262 	 * other than the end-points:
1263 	 */
1264 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1265 
1266 	old_port_status = max3421_hcd->port_status;
1267 	if (hirq & BIT(MAX3421_HI_BUSEVENT_BIT)) {
1268 		if (max3421_hcd->port_status & USB_PORT_STAT_RESET) {
1269 			/* BUSEVENT due to completion of Bus Reset */
1270 			max3421_hcd->port_status &= ~USB_PORT_STAT_RESET;
1271 			max3421_hcd->port_status |=  USB_PORT_STAT_ENABLE;
1272 		} else {
1273 			/* BUSEVENT due to completion of Bus Resume */
1274 			pr_info("%s: BUSEVENT Bus Resume Done\n", __func__);
1275 		}
1276 	}
1277 	if (hirq & BIT(MAX3421_HI_RWU_BIT))
1278 		pr_info("%s: RWU\n", __func__);
1279 	if (hirq & BIT(MAX3421_HI_SUSDN_BIT))
1280 		pr_info("%s: SUSDN\n", __func__);
1281 
1282 	chg = (old_port_status ^ max3421_hcd->port_status);
1283 	max3421_hcd->port_status |= chg << 16;
1284 
1285 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1286 
1287 #ifdef DEBUG
1288 	{
1289 		static unsigned long last_time;
1290 		char sbuf[16 * 16], *dp, *end;
1291 		int i;
1292 
1293 		if (time_after(jiffies, last_time + 5*HZ)) {
1294 			dp = sbuf;
1295 			end = sbuf + sizeof(sbuf);
1296 			*dp = '\0';
1297 			for (i = 0; i < 16; ++i) {
1298 				int ret = snprintf(dp, end - dp, " %lu",
1299 						   max3421_hcd->err_stat[i]);
1300 				if (ret < 0 || ret >= end - dp)
1301 					break;	/* error or buffer full */
1302 				dp += ret;
1303 			}
1304 			pr_info("%s: hrsl_stats %s\n", __func__, sbuf);
1305 			memset(max3421_hcd->err_stat, 0,
1306 			       sizeof(max3421_hcd->err_stat));
1307 			last_time = jiffies;
1308 
1309 			dump_eps(hcd);
1310 		}
1311 	}
1312 #endif
1313 	return 1;
1314 }
1315 
1316 static int
1317 max3421_reset_hcd(struct usb_hcd *hcd)
1318 {
1319 	struct spi_device *spi = to_spi_device(hcd->self.controller);
1320 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1321 	int timeout;
1322 
1323 	/* perform a chip reset and wait for OSCIRQ signal to appear: */
1324 	spi_wr8(hcd, MAX3421_REG_USBCTL, BIT(MAX3421_USBCTL_CHIPRES_BIT));
1325 	/* clear reset: */
1326 	spi_wr8(hcd, MAX3421_REG_USBCTL, 0);
1327 	timeout = 1000;
1328 	while (1) {
1329 		if (spi_rd8(hcd, MAX3421_REG_USBIRQ)
1330 		    & BIT(MAX3421_USBIRQ_OSCOKIRQ_BIT))
1331 			break;
1332 		if (--timeout < 0) {
1333 			dev_err(&spi->dev,
1334 				"timed out waiting for oscillator OK signal");
1335 			return 1;
1336 		}
1337 		cond_resched();
1338 	}
1339 
1340 	/*
1341 	 * Turn on host mode, automatic generation of SOF packets, and
1342 	 * enable pull-down registers on DM/DP:
1343 	 */
1344 	max3421_hcd->mode = (BIT(MAX3421_MODE_HOST_BIT) |
1345 			     BIT(MAX3421_MODE_SOFKAENAB_BIT) |
1346 			     BIT(MAX3421_MODE_DMPULLDN_BIT) |
1347 			     BIT(MAX3421_MODE_DPPULLDN_BIT));
1348 	spi_wr8(hcd, MAX3421_REG_MODE, max3421_hcd->mode);
1349 
1350 	/* reset frame-number: */
1351 	max3421_hcd->frame_number = USB_MAX_FRAME_NUMBER;
1352 	spi_wr8(hcd, MAX3421_REG_HCTL, BIT(MAX3421_HCTL_FRMRST_BIT));
1353 
1354 	/* sample the state of the D+ and D- lines */
1355 	spi_wr8(hcd, MAX3421_REG_HCTL, BIT(MAX3421_HCTL_SAMPLEBUS_BIT));
1356 	max3421_detect_conn(hcd);
1357 
1358 	/* enable frame, connection-detected, and bus-event interrupts: */
1359 	max3421_hcd->hien = (BIT(MAX3421_HI_FRAME_BIT) |
1360 			     BIT(MAX3421_HI_CONDET_BIT) |
1361 			     BIT(MAX3421_HI_BUSEVENT_BIT));
1362 	spi_wr8(hcd, MAX3421_REG_HIEN, max3421_hcd->hien);
1363 
1364 	/* enable interrupts: */
1365 	spi_wr8(hcd, MAX3421_REG_CPUCTL, BIT(MAX3421_CPUCTL_IE_BIT));
1366 	return 1;
1367 }
1368 
1369 static int
1370 max3421_urb_done(struct usb_hcd *hcd)
1371 {
1372 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1373 	unsigned long flags;
1374 	struct urb *urb;
1375 	int status;
1376 
1377 	status = max3421_hcd->urb_done;
1378 	max3421_hcd->urb_done = 0;
1379 	if (status > 0)
1380 		status = 0;
1381 	urb = max3421_hcd->curr_urb;
1382 	if (urb) {
1383 		max3421_hcd->curr_urb = NULL;
1384 		spin_lock_irqsave(&max3421_hcd->lock, flags);
1385 		usb_hcd_unlink_urb_from_ep(hcd, urb);
1386 		spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1387 
1388 		/* must be called without the HCD spinlock: */
1389 		usb_hcd_giveback_urb(hcd, urb, status);
1390 	}
1391 	return 1;
1392 }
1393 
1394 static int
1395 max3421_spi_thread(void *dev_id)
1396 {
1397 	struct usb_hcd *hcd = dev_id;
1398 	struct spi_device *spi = to_spi_device(hcd->self.controller);
1399 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1400 	int i, i_worked = 1;
1401 
1402 	/* set full-duplex SPI mode, low-active interrupt pin: */
1403 	spi_wr8(hcd, MAX3421_REG_PINCTL,
1404 		(BIT(MAX3421_PINCTL_FDUPSPI_BIT) |	/* full-duplex */
1405 		 BIT(MAX3421_PINCTL_INTLEVEL_BIT)));	/* low-active irq */
1406 
1407 	while (!kthread_should_stop()) {
1408 		max3421_hcd->rev = spi_rd8(hcd, MAX3421_REG_REVISION);
1409 		if (max3421_hcd->rev == 0x12 || max3421_hcd->rev == 0x13)
1410 			break;
1411 		dev_err(&spi->dev, "bad rev 0x%02x", max3421_hcd->rev);
1412 		msleep(10000);
1413 	}
1414 	dev_info(&spi->dev, "rev 0x%x, SPI clk %dHz, bpw %u, irq %d\n",
1415 		 max3421_hcd->rev, spi->max_speed_hz, spi->bits_per_word,
1416 		 spi->irq);
1417 
1418 	while (!kthread_should_stop()) {
1419 		if (!i_worked) {
1420 			/*
1421 			 * We'll be waiting for wakeups from the hard
1422 			 * interrupt handler, so now is a good time to
1423 			 * sync our hien with the chip:
1424 			 */
1425 			spi_wr8(hcd, MAX3421_REG_HIEN, max3421_hcd->hien);
1426 
1427 			set_current_state(TASK_INTERRUPTIBLE);
1428 			if (test_and_clear_bit(ENABLE_IRQ, &max3421_hcd->todo))
1429 				enable_irq(spi->irq);
1430 			schedule();
1431 			__set_current_state(TASK_RUNNING);
1432 		}
1433 
1434 		i_worked = 0;
1435 
1436 		if (max3421_hcd->urb_done)
1437 			i_worked |= max3421_urb_done(hcd);
1438 		else if (max3421_handle_irqs(hcd))
1439 			i_worked = 1;
1440 		else if (!max3421_hcd->curr_urb)
1441 			i_worked |= max3421_select_and_start_urb(hcd);
1442 
1443 		if (test_and_clear_bit(RESET_HCD, &max3421_hcd->todo))
1444 			/* reset the HCD: */
1445 			i_worked |= max3421_reset_hcd(hcd);
1446 		if (test_and_clear_bit(RESET_PORT, &max3421_hcd->todo)) {
1447 			/* perform a USB bus reset: */
1448 			spi_wr8(hcd, MAX3421_REG_HCTL,
1449 				BIT(MAX3421_HCTL_BUSRST_BIT));
1450 			i_worked = 1;
1451 		}
1452 		if (test_and_clear_bit(CHECK_UNLINK, &max3421_hcd->todo))
1453 			i_worked |= max3421_check_unlink(hcd);
1454 		if (test_and_clear_bit(IOPIN_UPDATE, &max3421_hcd->todo)) {
1455 			/*
1456 			 * IOPINS1/IOPINS2 do not auto-increment, so we can't
1457 			 * use spi_wr_buf().
1458 			 */
1459 			for (i = 0; i < ARRAY_SIZE(max3421_hcd->iopins); ++i) {
1460 				u8 val = spi_rd8(hcd, MAX3421_REG_IOPINS1);
1461 
1462 				val = ((val & 0xf0) |
1463 				       (max3421_hcd->iopins[i] & 0x0f));
1464 				spi_wr8(hcd, MAX3421_REG_IOPINS1 + i, val);
1465 				max3421_hcd->iopins[i] = val;
1466 			}
1467 			i_worked = 1;
1468 		}
1469 	}
1470 	set_current_state(TASK_RUNNING);
1471 	dev_info(&spi->dev, "SPI thread exiting");
1472 	return 0;
1473 }
1474 
1475 static int
1476 max3421_reset_port(struct usb_hcd *hcd)
1477 {
1478 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1479 
1480 	max3421_hcd->port_status &= ~(USB_PORT_STAT_ENABLE |
1481 				      USB_PORT_STAT_LOW_SPEED);
1482 	max3421_hcd->port_status |= USB_PORT_STAT_RESET;
1483 	set_bit(RESET_PORT, &max3421_hcd->todo);
1484 	wake_up_process(max3421_hcd->spi_thread);
1485 	return 0;
1486 }
1487 
1488 static int
1489 max3421_reset(struct usb_hcd *hcd)
1490 {
1491 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1492 
1493 	hcd->self.sg_tablesize = 0;
1494 	hcd->speed = HCD_USB2;
1495 	hcd->self.root_hub->speed = USB_SPEED_FULL;
1496 	set_bit(RESET_HCD, &max3421_hcd->todo);
1497 	wake_up_process(max3421_hcd->spi_thread);
1498 	return 0;
1499 }
1500 
1501 static int
1502 max3421_start(struct usb_hcd *hcd)
1503 {
1504 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1505 
1506 	spin_lock_init(&max3421_hcd->lock);
1507 	max3421_hcd->rh_state = MAX3421_RH_RUNNING;
1508 
1509 	INIT_LIST_HEAD(&max3421_hcd->ep_list);
1510 
1511 	hcd->power_budget = POWER_BUDGET;
1512 	hcd->state = HC_STATE_RUNNING;
1513 	hcd->uses_new_polling = 1;
1514 	return 0;
1515 }
1516 
1517 static void
1518 max3421_stop(struct usb_hcd *hcd)
1519 {
1520 }
1521 
1522 static int
1523 max3421_urb_enqueue(struct usb_hcd *hcd, struct urb *urb, gfp_t mem_flags)
1524 {
1525 	struct spi_device *spi = to_spi_device(hcd->self.controller);
1526 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1527 	struct max3421_ep *max3421_ep;
1528 	unsigned long flags;
1529 	int retval;
1530 
1531 	switch (usb_pipetype(urb->pipe)) {
1532 	case PIPE_INTERRUPT:
1533 	case PIPE_ISOCHRONOUS:
1534 		if (urb->interval < 0) {
1535 			dev_err(&spi->dev,
1536 			  "%s: interval=%d for intr-/iso-pipe; expected > 0\n",
1537 				__func__, urb->interval);
1538 			return -EINVAL;
1539 		}
1540 		break;
1541 	default:
1542 		break;
1543 	}
1544 
1545 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1546 
1547 	max3421_ep = urb->ep->hcpriv;
1548 	if (!max3421_ep) {
1549 		/* gets freed in max3421_endpoint_disable: */
1550 		max3421_ep = kzalloc(sizeof(struct max3421_ep), GFP_ATOMIC);
1551 		if (!max3421_ep) {
1552 			retval = -ENOMEM;
1553 			goto out;
1554 		}
1555 		max3421_ep->ep = urb->ep;
1556 		max3421_ep->last_active = max3421_hcd->frame_number;
1557 		urb->ep->hcpriv = max3421_ep;
1558 
1559 		list_add_tail(&max3421_ep->ep_list, &max3421_hcd->ep_list);
1560 	}
1561 
1562 	retval = usb_hcd_link_urb_to_ep(hcd, urb);
1563 	if (retval == 0) {
1564 		/* Since we added to the queue, restart scheduling: */
1565 		max3421_hcd->sched_pass = SCHED_PASS_PERIODIC;
1566 		wake_up_process(max3421_hcd->spi_thread);
1567 	}
1568 
1569 out:
1570 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1571 	return retval;
1572 }
1573 
1574 static int
1575 max3421_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
1576 {
1577 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1578 	unsigned long flags;
1579 	int retval;
1580 
1581 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1582 
1583 	/*
1584 	 * This will set urb->unlinked which in turn causes the entry
1585 	 * to be dropped at the next opportunity.
1586 	 */
1587 	retval = usb_hcd_check_unlink_urb(hcd, urb, status);
1588 	if (retval == 0) {
1589 		set_bit(CHECK_UNLINK, &max3421_hcd->todo);
1590 		wake_up_process(max3421_hcd->spi_thread);
1591 	}
1592 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1593 	return retval;
1594 }
1595 
1596 static void
1597 max3421_endpoint_disable(struct usb_hcd *hcd, struct usb_host_endpoint *ep)
1598 {
1599 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1600 	unsigned long flags;
1601 
1602 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1603 
1604 	if (ep->hcpriv) {
1605 		struct max3421_ep *max3421_ep = ep->hcpriv;
1606 
1607 		/* remove myself from the ep_list: */
1608 		if (!list_empty(&max3421_ep->ep_list))
1609 			list_del(&max3421_ep->ep_list);
1610 		kfree(max3421_ep);
1611 		ep->hcpriv = NULL;
1612 	}
1613 
1614 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1615 }
1616 
1617 static int
1618 max3421_get_frame_number(struct usb_hcd *hcd)
1619 {
1620 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1621 	return max3421_hcd->frame_number;
1622 }
1623 
1624 /*
1625  * Should return a non-zero value when any port is undergoing a resume
1626  * transition while the root hub is suspended.
1627  */
1628 static int
1629 max3421_hub_status_data(struct usb_hcd *hcd, char *buf)
1630 {
1631 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1632 	unsigned long flags;
1633 	int retval = 0;
1634 
1635 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1636 	if (!HCD_HW_ACCESSIBLE(hcd))
1637 		goto done;
1638 
1639 	*buf = 0;
1640 	if ((max3421_hcd->port_status & PORT_C_MASK) != 0) {
1641 		*buf = (1 << 1); /* a hub over-current condition exists */
1642 		dev_dbg(hcd->self.controller,
1643 			"port status 0x%08x has changes\n",
1644 			max3421_hcd->port_status);
1645 		retval = 1;
1646 		if (max3421_hcd->rh_state == MAX3421_RH_SUSPENDED)
1647 			usb_hcd_resume_root_hub(hcd);
1648 	}
1649 done:
1650 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1651 	return retval;
1652 }
1653 
1654 static inline void
1655 hub_descriptor(struct usb_hub_descriptor *desc)
1656 {
1657 	memset(desc, 0, sizeof(*desc));
1658 	/*
1659 	 * See Table 11-13: Hub Descriptor in USB 2.0 spec.
1660 	 */
1661 	desc->bDescriptorType = USB_DT_HUB; /* hub descriptor */
1662 	desc->bDescLength = 9;
1663 	desc->wHubCharacteristics = cpu_to_le16(HUB_CHAR_INDV_PORT_LPSM |
1664 						HUB_CHAR_COMMON_OCPM);
1665 	desc->bNbrPorts = 1;
1666 }
1667 
1668 /*
1669  * Set the MAX3421E general-purpose output with number PIN_NUMBER to
1670  * VALUE (0 or 1).  PIN_NUMBER may be in the range from 1-8.  For
1671  * any other value, this function acts as a no-op.
1672  */
1673 static void
1674 max3421_gpout_set_value(struct usb_hcd *hcd, u8 pin_number, u8 value)
1675 {
1676 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1677 	u8 mask, idx;
1678 
1679 	--pin_number;
1680 	if (pin_number >= MAX3421_GPOUT_COUNT)
1681 		return;
1682 
1683 	mask = 1u << (pin_number % 4);
1684 	idx = pin_number / 4;
1685 
1686 	if (value)
1687 		max3421_hcd->iopins[idx] |=  mask;
1688 	else
1689 		max3421_hcd->iopins[idx] &= ~mask;
1690 	set_bit(IOPIN_UPDATE, &max3421_hcd->todo);
1691 	wake_up_process(max3421_hcd->spi_thread);
1692 }
1693 
1694 static int
1695 max3421_hub_control(struct usb_hcd *hcd, u16 type_req, u16 value, u16 index,
1696 		    char *buf, u16 length)
1697 {
1698 	struct spi_device *spi = to_spi_device(hcd->self.controller);
1699 	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1700 	struct max3421_hcd_platform_data *pdata;
1701 	unsigned long flags;
1702 	int retval = 0;
1703 
1704 	pdata = spi->dev.platform_data;
1705 
1706 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1707 
1708 	switch (type_req) {
1709 	case ClearHubFeature:
1710 		break;
1711 	case ClearPortFeature:
1712 		switch (value) {
1713 		case USB_PORT_FEAT_SUSPEND:
1714 			break;
1715 		case USB_PORT_FEAT_POWER:
1716 			dev_dbg(hcd->self.controller, "power-off\n");
1717 			max3421_gpout_set_value(hcd, pdata->vbus_gpout,
1718 						!pdata->vbus_active_level);
1719 			fallthrough;
1720 		default:
1721 			max3421_hcd->port_status &= ~(1 << value);
1722 		}
1723 		break;
1724 	case GetHubDescriptor:
1725 		hub_descriptor((struct usb_hub_descriptor *) buf);
1726 		break;
1727 
1728 	case DeviceRequest | USB_REQ_GET_DESCRIPTOR:
1729 	case GetPortErrorCount:
1730 	case SetHubDepth:
1731 		/* USB3 only */
1732 		goto error;
1733 
1734 	case GetHubStatus:
1735 		*(__le32 *) buf = cpu_to_le32(0);
1736 		break;
1737 
1738 	case GetPortStatus:
1739 		if (index != 1) {
1740 			retval = -EPIPE;
1741 			goto error;
1742 		}
1743 		((__le16 *) buf)[0] = cpu_to_le16(max3421_hcd->port_status);
1744 		((__le16 *) buf)[1] =
1745 			cpu_to_le16(max3421_hcd->port_status >> 16);
1746 		break;
1747 
1748 	case SetHubFeature:
1749 		retval = -EPIPE;
1750 		break;
1751 
1752 	case SetPortFeature:
1753 		switch (value) {
1754 		case USB_PORT_FEAT_LINK_STATE:
1755 		case USB_PORT_FEAT_U1_TIMEOUT:
1756 		case USB_PORT_FEAT_U2_TIMEOUT:
1757 		case USB_PORT_FEAT_BH_PORT_RESET:
1758 			goto error;
1759 		case USB_PORT_FEAT_SUSPEND:
1760 			if (max3421_hcd->active)
1761 				max3421_hcd->port_status |=
1762 					USB_PORT_STAT_SUSPEND;
1763 			break;
1764 		case USB_PORT_FEAT_POWER:
1765 			dev_dbg(hcd->self.controller, "power-on\n");
1766 			max3421_hcd->port_status |= USB_PORT_STAT_POWER;
1767 			max3421_gpout_set_value(hcd, pdata->vbus_gpout,
1768 						pdata->vbus_active_level);
1769 			break;
1770 		case USB_PORT_FEAT_RESET:
1771 			max3421_reset_port(hcd);
1772 			fallthrough;
1773 		default:
1774 			if ((max3421_hcd->port_status & USB_PORT_STAT_POWER)
1775 			    != 0)
1776 				max3421_hcd->port_status |= (1 << value);
1777 		}
1778 		break;
1779 
1780 	default:
1781 		dev_dbg(hcd->self.controller,
1782 			"hub control req%04x v%04x i%04x l%d\n",
1783 			type_req, value, index, length);
1784 error:		/* "protocol stall" on error */
1785 		retval = -EPIPE;
1786 	}
1787 
1788 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1789 	return retval;
1790 }
1791 
1792 static int
1793 max3421_bus_suspend(struct usb_hcd *hcd)
1794 {
1795 	return -1;
1796 }
1797 
1798 static int
1799 max3421_bus_resume(struct usb_hcd *hcd)
1800 {
1801 	return -1;
1802 }
1803 
1804 static const struct hc_driver max3421_hcd_desc = {
1805 	.description =		"max3421",
1806 	.product_desc =		DRIVER_DESC,
1807 	.hcd_priv_size =	sizeof(struct max3421_hcd),
1808 	.flags =		HCD_USB11,
1809 	.reset =		max3421_reset,
1810 	.start =		max3421_start,
1811 	.stop =			max3421_stop,
1812 	.get_frame_number =	max3421_get_frame_number,
1813 	.urb_enqueue =		max3421_urb_enqueue,
1814 	.urb_dequeue =		max3421_urb_dequeue,
1815 	.endpoint_disable =	max3421_endpoint_disable,
1816 	.hub_status_data =	max3421_hub_status_data,
1817 	.hub_control =		max3421_hub_control,
1818 	.bus_suspend =		max3421_bus_suspend,
1819 	.bus_resume =		max3421_bus_resume,
1820 };
1821 
1822 static int
1823 max3421_of_vbus_en_pin(struct device *dev, struct max3421_hcd_platform_data *pdata)
1824 {
1825 	int retval;
1826 	uint32_t value[2];
1827 
1828 	if (!pdata)
1829 		return -EINVAL;
1830 
1831 	retval = of_property_read_u32_array(dev->of_node, "maxim,vbus-en-pin", value, 2);
1832 	if (retval) {
1833 		dev_err(dev, "device tree node property 'maxim,vbus-en-pin' is missing\n");
1834 		return retval;
1835 	}
1836 	dev_info(dev, "property 'maxim,vbus-en-pin' value is <%d %d>\n", value[0], value[1]);
1837 
1838 	pdata->vbus_gpout = value[0];
1839 	pdata->vbus_active_level = value[1];
1840 
1841 	return 0;
1842 }
1843 
1844 static int
1845 max3421_probe(struct spi_device *spi)
1846 {
1847 	struct device *dev = &spi->dev;
1848 	struct max3421_hcd *max3421_hcd;
1849 	struct usb_hcd *hcd = NULL;
1850 	struct max3421_hcd_platform_data *pdata = NULL;
1851 	int retval;
1852 
1853 	if (spi_setup(spi) < 0) {
1854 		dev_err(&spi->dev, "Unable to setup SPI bus");
1855 		return -EFAULT;
1856 	}
1857 
1858 	if (!spi->irq) {
1859 		dev_err(dev, "Failed to get SPI IRQ");
1860 		return -EFAULT;
1861 	}
1862 
1863 	if (IS_ENABLED(CONFIG_OF) && dev->of_node) {
1864 		pdata = devm_kzalloc(&spi->dev, sizeof(*pdata), GFP_KERNEL);
1865 		if (!pdata) {
1866 			retval = -ENOMEM;
1867 			goto error;
1868 		}
1869 		retval = max3421_of_vbus_en_pin(dev, pdata);
1870 		if (retval)
1871 			goto error;
1872 
1873 		spi->dev.platform_data = pdata;
1874 	}
1875 
1876 	pdata = spi->dev.platform_data;
1877 	if (!pdata) {
1878 		dev_err(&spi->dev, "driver configuration data is not provided\n");
1879 		retval = -EFAULT;
1880 		goto error;
1881 	}
1882 	if (pdata->vbus_active_level > 1) {
1883 		dev_err(&spi->dev, "vbus active level value %d is out of range (0/1)\n", pdata->vbus_active_level);
1884 		retval = -EINVAL;
1885 		goto error;
1886 	}
1887 	if (pdata->vbus_gpout < 1 || pdata->vbus_gpout > MAX3421_GPOUT_COUNT) {
1888 		dev_err(&spi->dev, "vbus gpout value %d is out of range (1..8)\n", pdata->vbus_gpout);
1889 		retval = -EINVAL;
1890 		goto error;
1891 	}
1892 
1893 	retval = -ENOMEM;
1894 	hcd = usb_create_hcd(&max3421_hcd_desc, &spi->dev,
1895 			     dev_name(&spi->dev));
1896 	if (!hcd) {
1897 		dev_err(&spi->dev, "failed to create HCD structure\n");
1898 		goto error;
1899 	}
1900 	set_bit(HCD_FLAG_POLL_RH, &hcd->flags);
1901 	max3421_hcd = hcd_to_max3421(hcd);
1902 	max3421_hcd->next = max3421_hcd_list;
1903 	max3421_hcd_list = max3421_hcd;
1904 	INIT_LIST_HEAD(&max3421_hcd->ep_list);
1905 
1906 	max3421_hcd->tx = kmalloc(sizeof(*max3421_hcd->tx), GFP_KERNEL);
1907 	if (!max3421_hcd->tx)
1908 		goto error;
1909 	max3421_hcd->rx = kmalloc(sizeof(*max3421_hcd->rx), GFP_KERNEL);
1910 	if (!max3421_hcd->rx)
1911 		goto error;
1912 
1913 	max3421_hcd->spi_thread = kthread_run(max3421_spi_thread, hcd,
1914 					      "max3421_spi_thread");
1915 	if (max3421_hcd->spi_thread == ERR_PTR(-ENOMEM)) {
1916 		dev_err(&spi->dev,
1917 			"failed to create SPI thread (out of memory)\n");
1918 		goto error;
1919 	}
1920 
1921 	retval = usb_add_hcd(hcd, 0, 0);
1922 	if (retval) {
1923 		dev_err(&spi->dev, "failed to add HCD\n");
1924 		goto error;
1925 	}
1926 
1927 	retval = request_irq(spi->irq, max3421_irq_handler,
1928 			     IRQF_TRIGGER_LOW, "max3421", hcd);
1929 	if (retval < 0) {
1930 		dev_err(&spi->dev, "failed to request irq %d\n", spi->irq);
1931 		goto error;
1932 	}
1933 	return 0;
1934 
1935 error:
1936 	if (IS_ENABLED(CONFIG_OF) && dev->of_node && pdata) {
1937 		devm_kfree(&spi->dev, pdata);
1938 		spi->dev.platform_data = NULL;
1939 	}
1940 
1941 	if (hcd) {
1942 		kfree(max3421_hcd->tx);
1943 		kfree(max3421_hcd->rx);
1944 		if (max3421_hcd->spi_thread)
1945 			kthread_stop(max3421_hcd->spi_thread);
1946 		usb_put_hcd(hcd);
1947 	}
1948 	return retval;
1949 }
1950 
1951 static int
1952 max3421_remove(struct spi_device *spi)
1953 {
1954 	struct max3421_hcd *max3421_hcd = NULL, **prev;
1955 	struct usb_hcd *hcd = NULL;
1956 	unsigned long flags;
1957 
1958 	for (prev = &max3421_hcd_list; *prev; prev = &(*prev)->next) {
1959 		max3421_hcd = *prev;
1960 		hcd = max3421_to_hcd(max3421_hcd);
1961 		if (hcd->self.controller == &spi->dev)
1962 			break;
1963 	}
1964 	if (!max3421_hcd) {
1965 		dev_err(&spi->dev, "no MAX3421 HCD found for SPI device %p\n",
1966 			spi);
1967 		return -ENODEV;
1968 	}
1969 
1970 	usb_remove_hcd(hcd);
1971 
1972 	spin_lock_irqsave(&max3421_hcd->lock, flags);
1973 
1974 	kthread_stop(max3421_hcd->spi_thread);
1975 	*prev = max3421_hcd->next;
1976 
1977 	spin_unlock_irqrestore(&max3421_hcd->lock, flags);
1978 
1979 	free_irq(spi->irq, hcd);
1980 
1981 	usb_put_hcd(hcd);
1982 	return 0;
1983 }
1984 
1985 static const struct of_device_id max3421_of_match_table[] = {
1986 	{ .compatible = "maxim,max3421", },
1987 	{},
1988 };
1989 MODULE_DEVICE_TABLE(of, max3421_of_match_table);
1990 
1991 static struct spi_driver max3421_driver = {
1992 	.probe		= max3421_probe,
1993 	.remove		= max3421_remove,
1994 	.driver		= {
1995 		.name	= "max3421-hcd",
1996 		.of_match_table = of_match_ptr(max3421_of_match_table),
1997 	},
1998 };
1999 
2000 module_spi_driver(max3421_driver);
2001 
2002 MODULE_DESCRIPTION(DRIVER_DESC);
2003 MODULE_AUTHOR("David Mosberger <davidm@egauge.net>");
2004 MODULE_LICENSE("GPL");
2005