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(dev: 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(m: &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(t: &transfer, m: &msg);
361	spi_sync(spi, message: &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(dev: 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(m: &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(t: &transfer, m: &msg);
387	spi_sync(spi, message: &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(dev: 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(m: &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(t: &transfer[0], m: &msg);
412	spi_message_add_tail(t: &transfer[1], m: &msg);
413	spi_sync(spi, message: &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(dev: 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(m: &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(t: &transfer[0], m: &msg);
439	spi_message_add_tail(t: &transfer[1], m: &msg);
440	spi_sync(spi, message: &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, val: 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, val: 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, val: 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, buf: urb->setup_packet, len: 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(dev: 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, val: 0);
537	spi_wr8(hcd, MAX3421_REG_SNDFIFO, val: ((u8 *) src)[0]);
538	spi_wr8(hcd, MAX3421_REG_SNDBC, val: max3421_hcd->curr_len);
539	}
540	return MAX3421_HXFR_BULK_OUT(epnum);
541	}
542
543	max_packet = usb_maxpacket(udev: urb->dev, pipe: 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, buf: src, len: max3421_hcd->curr_len);
560	spi_wr8(hcd, MAX3421_REG_SNDBC, val: 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, val: 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(dev: 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(epd: &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(head: &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(lock: &max3421_hcd->lock,
677	flags);
678	return 1;
679	}
680
681	switch (usb_endpoint_type(epd: &ep->desc)) {
682	case USB_ENDPOINT_XFER_CONTROL:
683	/*
684	* Allow one control transaction per
685	* frame per endpoint:
686	*/
687	if (frame_diff(left: max3421_ep->last_active,
688	right: max3421_hcd->frame_number) == 0)
689	continue;
690	break;
691
692	case USB_ENDPOINT_XFER_BULK:
693	if (max3421_ep->retransmit
694	&& (frame_diff(left: max3421_ep->last_active,
695	right: 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(left: max3421_hcd->frame_number,
708	right: 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(list: pos, head: &max3421_hcd->ep_list);
721	curr_urb = urb;
722	goto done;
723	}
724	done:
725	if (!curr_urb) {
726	spin_unlock_irqrestore(lock: &max3421_hcd->lock, flags);
727	return 0;
728	}
729
730	urb = max3421_hcd->curr_urb = curr_urb;
731	epnum = usb_endpoint_num(epd: &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(epd: &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(lock: &max3421_hcd->lock, flags);
750
751	max3421_ep->last_active = max3421_hcd->frame_number;
752	max3421_set_address(hcd, dev: urb->dev, epnum);
753	max3421_set_speed(hcd, dev: urb->dev);
754	max3421_next_transfer(hcd, fast_retransmit: 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(dev: 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(lock: &max3421_hcd->lock,
784	flags);
785	usb_hcd_giveback_urb(hcd, urb, status: 0);
786	spin_lock_irqsave(&max3421_hcd->lock, flags);
787	}
788	}
789	}
790	spin_unlock_irqrestore(lock: &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, buf: dst, len: 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(dev: 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, fast_retransmit: 1);
922	switch_sndfifo = 0;
923	break;
924	}
925	if (switch_sndfifo)
926	spi_wr8(hcd, MAX3421_REG_SNDBC, val: 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(dev: 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(udev: urb->dev, pipe: 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(udev: urb->dev, pipe: 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, fast_retransmit: 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, val: 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(lock: &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(dev: hcd->self.controller);
1131	struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
1132
1133	if (max3421_hcd->spi_thread)
1134	wake_up_process(tsk: max3421_hcd->spi_thread);
1135	if (!test_and_set_bit(nr: ENABLE_IRQ, addr: &max3421_hcd->todo))
1136	disable_irq_nosync(irq: 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 = scnprintf(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 == end - dp - 1)
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	val: 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(lock: &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 = scnprintf(dp, end - dp, " %lu",
1259	max3421_hcd->err_stat[i]);
1260	if (ret == end - dp - 1)
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(dev: 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, val: 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, val: 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, val: 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(epd: &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(lock: &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(dev: 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	val: (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(msecs: 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, val: max3421_hcd->hien);
1396
1397	set_current_state(TASK_INTERRUPTIBLE);
1398	if (test_and_clear_bit(nr: ENABLE_IRQ, addr: &max3421_hcd->todo))
1399	enable_irq(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(nr: RESET_HCD, addr: &max3421_hcd->todo))
1414	/* reset the HCD: */
1415	i_worked |= max3421_reset_hcd(hcd);
1416	if (test_and_clear_bit(nr: RESET_PORT, addr: &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(nr: CHECK_UNLINK, addr: &max3421_hcd->todo))
1423	i_worked |= max3421_check_unlink(hcd);
1424	if (test_and_clear_bit(nr: IOPIN_UPDATE, addr: &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(nr: RESET_PORT, addr: &max3421_hcd->todo);
1454	wake_up_process(tsk: 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(nr: RESET_HCD, addr: &max3421_hcd->todo);
1467	wake_up_process(tsk: 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(list: &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(dev: 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(size: 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(new: &max3421_ep->ep_list, head: &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(tsk: max3421_hcd->spi_thread);
1537	}
1538
1539	out:
1540	spin_unlock_irqrestore(lock: &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(nr: CHECK_UNLINK, addr: &max3421_hcd->todo);
1560	wake_up_process(tsk: max3421_hcd->spi_thread);
1561	}
1562	spin_unlock_irqrestore(lock: &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(head: &max3421_ep->ep_list))
1579	list_del(entry: &max3421_ep->ep_list);
1580	kfree(objp: max3421_ep);
1581	ep->hcpriv = NULL;
1582	}
1583
1584	spin_unlock_irqrestore(lock: &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(lock: &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(nr: IOPIN_UPDATE, addr: &max3421_hcd->todo);
1661	wake_up_process(tsk: 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(dev: 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, pin_number: pdata->vbus_gpout,
1688	value: !pdata->vbus_active_level);
1689	fallthrough;
1690	default:
1691	max3421_hcd->port_status &= ~(1 << value);
1692	}
1693	break;
1694	case GetHubDescriptor:
1695	hub_descriptor(desc: (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, pin_number: pdata->vbus_gpout,
1738	value: 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(lock: &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(np: dev->of_node, propname: "maxim,vbus-en-pin", out_values: value, sz: 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(dev: &spi->dev, size: 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(driver: &max3421_hcd_desc, dev: &spi->dev,
1865	bus_name: dev_name(dev: &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, addr: &hcd->flags);
1871	max3421_hcd = hcd_to_max3421(hcd);
1872	INIT_LIST_HEAD(list: &max3421_hcd->ep_list);
1873	spi_set_drvdata(spi, data: max3421_hcd);
1874
1875	max3421_hcd->tx = kmalloc(size: sizeof(*max3421_hcd->tx), GFP_KERNEL);
1876	if (!max3421_hcd->tx)
1877	goto error;
1878	max3421_hcd->rx = kmalloc(size: 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(error: -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, irqnum: 0, irqflags: 0);
1891	if (retval) {
1892	dev_err(&spi->dev, "failed to add HCD\n");
1893	goto error;
1894	}
1895
1896	retval = request_irq(irq: spi->irq, handler: max3421_irq_handler,
1897	IRQF_TRIGGER_LOW, name: "max3421", dev: 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(dev: &spi->dev, p: pdata);
1907	spi->dev.platform_data = NULL;
1908	}
1909
1910	if (hcd) {
1911	kfree(objp: max3421_hcd->tx);
1912	kfree(objp: max3421_hcd->rx);
1913	if (max3421_hcd->spi_thread)
1914	kthread_stop(k: 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(k: max3421_hcd->spi_thread);
1935
1936	spin_unlock_irqrestore(lock: &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 = 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