1// SPDX-License-Identifier: GPL-2.0
2/*
3 * HMS Anybus-S Host Driver
4 *
5 * Copyright (C) 2018 Arcx Inc
6 */
7
8/*
9 * Architecture Overview
10 * =====================
11 * This driver (running on the CPU/SoC) and the Anybus-S card communicate
12 * by reading and writing data to/from the Anybus-S Dual-Port RAM (dpram).
13 * This is memory connected to both the SoC and Anybus-S card, which both sides
14 * can access freely and concurrently.
15 *
16 * Synchronization happens by means of two registers located in the dpram:
17 * IND_AB: written exclusively by the Anybus card; and
18 * IND_AP: written exclusively by this driver.
19 *
20 * Communication happens using one of the following mechanisms:
21 * 1. reserve, read/write, release dpram memory areas:
22 *	using an IND_AB/IND_AP protocol, the driver is able to reserve certain
23 *	memory areas. no dpram memory can be read or written except if reserved.
24 *	(with a few limited exceptions)
25 * 2. send and receive data structures via a shared mailbox:
26 *	using an IND_AB/IND_AP protocol, the driver and Anybus card are able to
27 *	exchange commands and responses using a shared mailbox.
28 * 3. receive software interrupts:
29 *	using an IND_AB/IND_AP protocol, the Anybus card is able to notify the
30 *	driver of certain events such as: bus online/offline, data available.
31 *	note that software interrupt event bits are located in a memory area
32 *	which must be reserved before it can be accessed.
33 *
34 * The manual[1] is silent on whether these mechanisms can happen concurrently,
35 * or how they should be synchronized. However, section 13 (Driver Example)
36 * provides the following suggestion for developing a driver:
37 * a) an interrupt handler which updates global variables;
38 * b) a continuously-running task handling area requests (1 above)
39 * c) a continuously-running task handling mailbox requests (2 above)
40 * The example conspicuously leaves out software interrupts (3 above), which
41 * is the thorniest issue to get right (see below).
42 *
43 * The naive, straightforward way to implement this would be:
44 * - create an isr which updates shared variables;
45 * - create a work_struct which handles software interrupts on a queue;
46 * - create a function which does reserve/update/unlock in a loop;
47 * - create a function which does mailbox send/receive in a loop;
48 * - call the above functions from the driver's read/write/ioctl;
49 * - synchronize using mutexes/spinlocks:
50 *	+ only one area request at a time
51 *	+ only one mailbox request at a time
52 *	+ protect AB_IND, AB_IND against data hazards (e.g. read-after-write)
53 *
54 * Unfortunately, the presence of the software interrupt causes subtle yet
55 * considerable synchronization issues; especially problematic is the
56 * requirement to reserve/release the area which contains the status bits.
57 *
58 * The driver architecture presented here sidesteps these synchronization issues
59 * by accessing the dpram from a single kernel thread only. User-space throws
60 * "tasks" (i.e. 1, 2 above) into a task queue, waits for their completion,
61 * and the kernel thread runs them to completion.
62 *
63 * Each task has a task_function, which is called/run by the queue thread.
64 * That function communicates with the Anybus card, and returns either
65 * 0 (OK), a negative error code (error), or -EINPROGRESS (waiting).
66 * On OK or error, the queue thread completes and dequeues the task,
67 * which also releases the user space thread which may still be waiting for it.
68 * On -EINPROGRESS (waiting), the queue thread will leave the task on the queue,
69 * and revisit (call again) whenever an interrupt event comes in.
70 *
71 * Each task has a state machine, which is run by calling its task_function.
72 * It ensures that the task will go through its various stages over time,
73 * returning -EINPROGRESS if it wants to wait for an event to happen.
74 *
75 * Note that according to the manual's driver example, the following operations
76 * may run independent of each other:
77 * - area reserve/read/write/release	(point 1 above)
78 * - mailbox operations			(point 2 above)
79 * - switching power on/off
80 *
81 * To allow them to run independently, each operation class gets its own queue.
82 *
83 * Userspace processes A, B, C, D post tasks to the appropriate queue,
84 * and wait for task completion:
85 *
86 *	process A	B	C	D
87 *		|	|	|	|
88 *		v	v	v	v
89 *	|<-----	========================================
90 *	|		|	   |		|
91 *	|		v	   v		v-------<-------+
92 *	|	+--------------------------------------+	|
93 *	|	| power q     | mbox q    | area q     |	|
94 *	|	|------------|------------|------------|	|
95 *	|	| task       | task       | task       |	|
96 *	|	| task       | task       | task       |	|
97 *	|	| task wait  | task wait  | task wait  |	|
98 *	|	+--------------------------------------+	|
99 *	|		^	   ^		^		|
100 *	|		|	   |		|		^
101 *	|	+--------------------------------------+	|
102 *	|	|	     queue thread	       |	|
103 *	|	|--------------------------------------|	|
104 *	|	| single-threaded:		       |	|
105 *	|	| loop:				       |	|
106 *	v	|   for each queue:		       |	|
107 *	|	|     run task state machine	       |	|
108 *	|	|     if task waiting:		       |	|
109 *	|	|       leave on queue		       |	|
110 *	|	|     if task done:		       |	|
111 *	|	|       complete task, remove from q   |	|
112 *	|	|   if software irq event bits set:    |	|
113 *	|	|     notify userspace		       |	|
114 *	|	|     post clear event bits task------>|>-------+
115 *	|	|   wait for IND_AB changed event OR   |
116 *	|	|            task added event	  OR   |
117 *	|	|	     timeout		       |
118 *	|	| end loop			       |
119 *	|	+--------------------------------------+
120 *	|	+		wake up		       +
121 *	|	+--------------------------------------+
122 *	|		^			^
123 *	|		|			|
124 *	+-------->-------			|
125 *						|
126 *		+--------------------------------------+
127 *		|	interrupt service routine      |
128 *		|--------------------------------------|
129 *		| wake up queue thread on IND_AB change|
130 *		+--------------------------------------+
131 *
132 * Note that the Anybus interrupt is dual-purpose:
133 * - after a reset, triggered when the card becomes ready;
134 * - during normal operation, triggered when AB_IND changes.
135 * This is why the interrupt service routine doesn't just wake up the
136 * queue thread, but also completes the card_boot completion.
137 *
138 * [1] https://www.anybus.com/docs/librariesprovider7/default-document-library/
139 *	manuals-design-guides/hms-hmsi-27-275.pdf
140 */
141
142#include <linux/kernel.h>
143#include <linux/module.h>
144#include <linux/init.h>
145#include <linux/slab.h>
146#include <linux/interrupt.h>
147#include <linux/atomic.h>
148#include <linux/kthread.h>
149#include <linux/kfifo.h>
150#include <linux/spinlock.h>
151#include <linux/uaccess.h>
152#include <linux/regmap.h>
153#include <linux/of.h>
154#include <linux/random.h>
155#include <linux/kref.h>
156#include <linux/of_address.h>
157
158/* move to <linux/anybuss-*.h> when taking this out of staging */
159#include "anybuss-client.h"
160#include "anybuss-controller.h"
161
162#define DPRAM_SIZE		0x800
163#define MAX_MBOX_MSG_SZ		0x0FF
164#define TIMEOUT			(HZ * 2)
165#define MAX_DATA_AREA_SZ	0x200
166#define MAX_FBCTRL_AREA_SZ	0x1BE
167
168#define REG_BOOTLOADER_V	0x7C0
169#define REG_API_V		0x7C2
170#define REG_FIELDBUS_V		0x7C4
171#define REG_SERIAL_NO		0x7C6
172#define REG_FIELDBUS_TYPE	0x7CC
173#define REG_MODULE_SW_V		0x7CE
174#define REG_IND_AB		0x7FF
175#define REG_IND_AP		0x7FE
176#define REG_EVENT_CAUSE		0x7ED
177#define MBOX_IN_AREA		0x400
178#define MBOX_OUT_AREA		0x520
179#define DATA_IN_AREA		0x000
180#define DATA_OUT_AREA		0x200
181#define FBCTRL_AREA		0x640
182
183#define EVENT_CAUSE_DC          0x01
184#define EVENT_CAUSE_FBOF        0x02
185#define EVENT_CAUSE_FBON        0x04
186
187#define IND_AB_UPDATED		0x08
188#define IND_AX_MIN		0x80
189#define IND_AX_MOUT		0x40
190#define IND_AX_IN		0x04
191#define IND_AX_OUT		0x02
192#define IND_AX_FBCTRL		0x01
193#define IND_AP_LOCK		0x08
194#define IND_AP_ACTION		0x10
195#define IND_AX_EVNT		0x20
196#define IND_AP_ABITS		(IND_AX_IN | IND_AX_OUT | \
197					IND_AX_FBCTRL | \
198					IND_AP_ACTION | IND_AP_LOCK)
199
200#define INFO_TYPE_FB		0x0002
201#define INFO_TYPE_APP		0x0001
202#define INFO_COMMAND		0x4000
203
204#define OP_MODE_FBFC		0x0002
205#define OP_MODE_FBS		0x0004
206#define OP_MODE_CD		0x0200
207
208#define CMD_START_INIT		0x0001
209#define CMD_ANYBUS_INIT		0x0002
210#define CMD_END_INIT		0x0003
211
212/*
213 * ---------------------------------------------------------------
214 * Anybus mailbox messages - definitions
215 * ---------------------------------------------------------------
216 * note that we're depending on the layout of these structures being
217 * exactly as advertised.
218 */
219
220struct anybus_mbox_hdr {
221	__be16 id;
222	__be16 info;
223	__be16 cmd_num;
224	__be16 data_size;
225	__be16 frame_count;
226	__be16 frame_num;
227	__be16 offset_high;
228	__be16 offset_low;
229	__be16 extended[8];
230};
231
232struct msg_anybus_init {
233	__be16 input_io_len;
234	__be16 input_dpram_len;
235	__be16 input_total_len;
236	__be16 output_io_len;
237	__be16 output_dpram_len;
238	__be16 output_total_len;
239	__be16 op_mode;
240	__be16 notif_config;
241	__be16 wd_val;
242};
243
244/* ------------- ref counted tasks ------------- */
245
246struct ab_task;
247typedef int (*ab_task_fn_t)(struct anybuss_host *cd,
248					struct ab_task *t);
249typedef void (*ab_done_fn_t)(struct anybuss_host *cd);
250
251struct area_priv {
252	bool is_write;
253	u16 flags;
254	u16 addr;
255	size_t count;
256	u8 buf[MAX_DATA_AREA_SZ];
257};
258
259struct mbox_priv {
260	struct anybus_mbox_hdr hdr;
261	size_t msg_out_sz;
262	size_t msg_in_sz;
263	u8 msg[MAX_MBOX_MSG_SZ];
264};
265
266struct ab_task {
267	struct kmem_cache	*cache;
268	struct kref		refcount;
269	ab_task_fn_t		task_fn;
270	ab_done_fn_t		done_fn;
271	int			result;
272	struct completion	done;
273	unsigned long		start_jiffies;
274	union {
275		struct area_priv area_pd;
276		struct mbox_priv mbox_pd;
277	};
278};
279
280static struct ab_task *ab_task_create_get(struct kmem_cache *cache,
281					  ab_task_fn_t task_fn)
282{
283	struct ab_task *t;
284
285	t = kmem_cache_alloc(cache, GFP_KERNEL);
286	if (!t)
287		return NULL;
288	t->cache = cache;
289	kref_init(&t->refcount);
290	t->task_fn = task_fn;
291	t->done_fn = NULL;
292	t->result = 0;
293	init_completion(&t->done);
294	return t;
295}
296
297static void __ab_task_destroy(struct kref *refcount)
298{
299	struct ab_task *t = container_of(refcount, struct ab_task, refcount);
300	struct kmem_cache *cache = t->cache;
301
302	kmem_cache_free(cache, t);
303}
304
305static void ab_task_put(struct ab_task *t)
306{
307	kref_put(&t->refcount, __ab_task_destroy);
308}
309
310static struct ab_task *__ab_task_get(struct ab_task *t)
311{
312	kref_get(&t->refcount);
313	return t;
314}
315
316static void __ab_task_finish(struct ab_task *t, struct anybuss_host *cd)
317{
318	if (t->done_fn)
319		t->done_fn(cd);
320	complete(&t->done);
321}
322
323static void
324ab_task_dequeue_finish_put(struct kfifo *q, struct anybuss_host *cd)
325{
326	int ret;
327	struct ab_task *t;
328
329	ret = kfifo_out(q, &t, sizeof(t));
330	WARN_ON(!ret);
331	__ab_task_finish(t, cd);
332	ab_task_put(t);
333}
334
335static int
336ab_task_enqueue(struct ab_task *t, struct kfifo *q, spinlock_t *slock,
337		wait_queue_head_t *wq)
338{
339	int ret;
340
341	t->start_jiffies = jiffies;
342	__ab_task_get(t);
343	ret = kfifo_in_spinlocked(q, &t, sizeof(t), slock);
344	if (!ret) {
345		ab_task_put(t);
346		return -ENOMEM;
347	}
348	wake_up(wq);
349	return 0;
350}
351
352static int
353ab_task_enqueue_wait(struct ab_task *t, struct kfifo *q, spinlock_t *slock,
354		     wait_queue_head_t *wq)
355{
356	int ret;
357
358	ret = ab_task_enqueue(t, q, slock, wq);
359	if (ret)
360		return ret;
361	ret = wait_for_completion_interruptible(&t->done);
362	if (ret)
363		return ret;
364	return t->result;
365}
366
367/* ------------------------ anybus hardware ------------------------ */
368
369struct anybuss_host {
370	struct device *dev;
371	struct anybuss_client *client;
372	void (*reset)(struct device *dev, bool assert);
373	struct regmap *regmap;
374	int irq;
375	int host_idx;
376	struct task_struct *qthread;
377	wait_queue_head_t wq;
378	struct completion card_boot;
379	atomic_t ind_ab;
380	spinlock_t qlock; /* protects IN side of powerq, mboxq, areaq */
381	struct kmem_cache *qcache;
382	struct kfifo qs[3];
383	struct kfifo *powerq;
384	struct kfifo *mboxq;
385	struct kfifo *areaq;
386	bool power_on;
387	bool softint_pending;
388};
389
390static void reset_assert(struct anybuss_host *cd)
391{
392	cd->reset(cd->dev, true);
393}
394
395static void reset_deassert(struct anybuss_host *cd)
396{
397	cd->reset(cd->dev, false);
398}
399
400static int test_dpram(struct regmap *regmap)
401{
402	int i;
403	unsigned int val;
404
405	for (i = 0; i < DPRAM_SIZE; i++)
406		regmap_write(regmap, i, (u8)i);
407	for (i = 0; i < DPRAM_SIZE; i++) {
408		regmap_read(regmap, i, &val);
409		if ((u8)val != (u8)i)
410			return -EIO;
411	}
412	return 0;
413}
414
415static int read_ind_ab(struct regmap *regmap)
416{
417	unsigned long timeout = jiffies + HZ / 2;
418	unsigned int a, b, i = 0;
419
420	while (time_before_eq(jiffies, timeout)) {
421		regmap_read(regmap, REG_IND_AB, &a);
422		regmap_read(regmap, REG_IND_AB, &b);
423		if (likely(a == b))
424			return (int)a;
425		if (i < 10) {
426			cpu_relax();
427			i++;
428		} else {
429			usleep_range(500, 1000);
430		}
431	}
432	WARN(1, "IND_AB register not stable");
433	return -ETIMEDOUT;
434}
435
436static int write_ind_ap(struct regmap *regmap, unsigned int ind_ap)
437{
438	unsigned long timeout = jiffies + HZ / 2;
439	unsigned int v, i = 0;
440
441	while (time_before_eq(jiffies, timeout)) {
442		regmap_write(regmap, REG_IND_AP, ind_ap);
443		regmap_read(regmap, REG_IND_AP, &v);
444		if (likely(ind_ap == v))
445			return 0;
446		if (i < 10) {
447			cpu_relax();
448			i++;
449		} else {
450			usleep_range(500, 1000);
451		}
452	}
453	WARN(1, "IND_AP register not stable");
454	return -ETIMEDOUT;
455}
456
457static irqreturn_t irq_handler(int irq, void *data)
458{
459	struct anybuss_host *cd = data;
460	int ind_ab;
461
462	/*
463	 * irq handler needs exclusive access to the IND_AB register,
464	 * because the act of reading the register acks the interrupt.
465	 *
466	 * store the register value in cd->ind_ab (an atomic_t), so that the
467	 * queue thread is able to read it without causing an interrupt ack
468	 * side-effect (and without spuriously acking an interrupt).
469	 */
470	ind_ab = read_ind_ab(cd->regmap);
471	if (ind_ab < 0)
472		return IRQ_NONE;
473	atomic_set(&cd->ind_ab, ind_ab);
474	complete(&cd->card_boot);
475	wake_up(&cd->wq);
476	return IRQ_HANDLED;
477}
478
479/* ------------------------ power on/off tasks --------------------- */
480
481static int task_fn_power_off(struct anybuss_host *cd,
482			     struct ab_task *t)
483{
484	struct anybuss_client *client = cd->client;
485
486	if (!cd->power_on)
487		return 0;
488	disable_irq(cd->irq);
489	reset_assert(cd);
490	atomic_set(&cd->ind_ab, IND_AB_UPDATED);
491	if (client->on_online_changed)
492		client->on_online_changed(client, false);
493	cd->power_on = false;
494	return 0;
495}
496
497static int task_fn_power_on_2(struct anybuss_host *cd,
498			      struct ab_task *t)
499{
500	if (completion_done(&cd->card_boot)) {
501		cd->power_on = true;
502		return 0;
503	}
504	if (time_after(jiffies, t->start_jiffies + TIMEOUT)) {
505		disable_irq(cd->irq);
506		reset_assert(cd);
507		dev_err(cd->dev, "power on timed out");
508		return -ETIMEDOUT;
509	}
510	return -EINPROGRESS;
511}
512
513static int task_fn_power_on(struct anybuss_host *cd,
514			    struct ab_task *t)
515{
516	unsigned int dummy;
517
518	if (cd->power_on)
519		return 0;
520	/*
521	 * anybus docs: prevent false 'init done' interrupt by
522	 * doing a dummy read of IND_AB register while in reset.
523	 */
524	regmap_read(cd->regmap, REG_IND_AB, &dummy);
525	reinit_completion(&cd->card_boot);
526	enable_irq(cd->irq);
527	reset_deassert(cd);
528	t->task_fn = task_fn_power_on_2;
529	return -EINPROGRESS;
530}
531
532int anybuss_set_power(struct anybuss_client *client, bool power_on)
533{
534	struct anybuss_host *cd = client->host;
535	struct ab_task *t;
536	int err;
537
538	t = ab_task_create_get(cd->qcache, power_on ?
539				task_fn_power_on : task_fn_power_off);
540	if (!t)
541		return -ENOMEM;
542	err = ab_task_enqueue_wait(t, cd->powerq, &cd->qlock, &cd->wq);
543	ab_task_put(t);
544	return err;
545}
546EXPORT_SYMBOL_GPL(anybuss_set_power);
547
548/* ---------------------------- area tasks ------------------------ */
549
550static int task_fn_area_3(struct anybuss_host *cd, struct ab_task *t)
551{
552	struct area_priv *pd = &t->area_pd;
553
554	if (!cd->power_on)
555		return -EIO;
556	if (atomic_read(&cd->ind_ab) & pd->flags) {
557		/* area not released yet */
558		if (time_after(jiffies, t->start_jiffies + TIMEOUT))
559			return -ETIMEDOUT;
560		return -EINPROGRESS;
561	}
562	return 0;
563}
564
565static int task_fn_area_2(struct anybuss_host *cd, struct ab_task *t)
566{
567	struct area_priv *pd = &t->area_pd;
568	unsigned int ind_ap;
569	int ret;
570
571	if (!cd->power_on)
572		return -EIO;
573	regmap_read(cd->regmap, REG_IND_AP, &ind_ap);
574	if (!(atomic_read(&cd->ind_ab) & pd->flags)) {
575		/* we don't own the area yet */
576		if (time_after(jiffies, t->start_jiffies + TIMEOUT)) {
577			dev_warn(cd->dev, "timeout waiting for area");
578			dump_stack();
579			return -ETIMEDOUT;
580		}
581		return -EINPROGRESS;
582	}
583	/* we own the area, do what we're here to do */
584	if (pd->is_write)
585		regmap_bulk_write(cd->regmap, pd->addr, pd->buf,
586				  pd->count);
587	else
588		regmap_bulk_read(cd->regmap, pd->addr, pd->buf,
589				 pd->count);
590	/* ask to release the area, must use unlocked release */
591	ind_ap &= ~IND_AP_ABITS;
592	ind_ap |= pd->flags;
593	ret = write_ind_ap(cd->regmap, ind_ap);
594	if (ret)
595		return ret;
596	t->task_fn = task_fn_area_3;
597	return -EINPROGRESS;
598}
599
600static int task_fn_area(struct anybuss_host *cd, struct ab_task *t)
601{
602	struct area_priv *pd = &t->area_pd;
603	unsigned int ind_ap;
604	int ret;
605
606	if (!cd->power_on)
607		return -EIO;
608	regmap_read(cd->regmap, REG_IND_AP, &ind_ap);
609	/* ask to take the area */
610	ind_ap &= ~IND_AP_ABITS;
611	ind_ap |= pd->flags | IND_AP_ACTION | IND_AP_LOCK;
612	ret = write_ind_ap(cd->regmap, ind_ap);
613	if (ret)
614		return ret;
615	t->task_fn = task_fn_area_2;
616	return -EINPROGRESS;
617}
618
619static struct ab_task *
620create_area_reader(struct kmem_cache *qcache, u16 flags, u16 addr,
621		   size_t count)
622{
623	struct ab_task *t;
624	struct area_priv *ap;
625
626	t = ab_task_create_get(qcache, task_fn_area);
627	if (!t)
628		return NULL;
629	ap = &t->area_pd;
630	ap->flags = flags;
631	ap->addr = addr;
632	ap->is_write = false;
633	ap->count = count;
634	return t;
635}
636
637static struct ab_task *
638create_area_writer(struct kmem_cache *qcache, u16 flags, u16 addr,
639		   const void *buf, size_t count)
640{
641	struct ab_task *t;
642	struct area_priv *ap;
643
644	t = ab_task_create_get(qcache, task_fn_area);
645	if (!t)
646		return NULL;
647	ap = &t->area_pd;
648	ap->flags = flags;
649	ap->addr = addr;
650	ap->is_write = true;
651	ap->count = count;
652	memcpy(ap->buf, buf, count);
653	return t;
654}
655
656static struct ab_task *
657create_area_user_writer(struct kmem_cache *qcache, u16 flags, u16 addr,
658			const void __user *buf, size_t count)
659{
660	struct ab_task *t;
661	struct area_priv *ap;
662
663	t = ab_task_create_get(qcache, task_fn_area);
664	if (!t)
665		return ERR_PTR(-ENOMEM);
666	ap = &t->area_pd;
667	ap->flags = flags;
668	ap->addr = addr;
669	ap->is_write = true;
670	ap->count = count;
671	if (copy_from_user(ap->buf, buf, count)) {
672		ab_task_put(t);
673		return ERR_PTR(-EFAULT);
674	}
675	return t;
676}
677
678static bool area_range_ok(u16 addr, size_t count, u16 area_start,
679			  size_t area_sz)
680{
681	u16 area_end_ex = area_start + area_sz;
682	u16 addr_end_ex;
683
684	if (addr < area_start)
685		return false;
686	if (addr >= area_end_ex)
687		return false;
688	addr_end_ex = addr + count;
689	if (addr_end_ex > area_end_ex)
690		return false;
691	return true;
692}
693
694/* -------------------------- mailbox tasks ----------------------- */
695
696static int task_fn_mbox_2(struct anybuss_host *cd, struct ab_task *t)
697{
698	struct mbox_priv *pd = &t->mbox_pd;
699	unsigned int ind_ap;
700
701	if (!cd->power_on)
702		return -EIO;
703	regmap_read(cd->regmap, REG_IND_AP, &ind_ap);
704	if (((atomic_read(&cd->ind_ab) ^ ind_ap) & IND_AX_MOUT) == 0) {
705		/* output message not here */
706		if (time_after(jiffies, t->start_jiffies + TIMEOUT))
707			return -ETIMEDOUT;
708		return -EINPROGRESS;
709	}
710	/* grab the returned header and msg */
711	regmap_bulk_read(cd->regmap, MBOX_OUT_AREA, &pd->hdr,
712			 sizeof(pd->hdr));
713	regmap_bulk_read(cd->regmap, MBOX_OUT_AREA + sizeof(pd->hdr),
714			 pd->msg, pd->msg_in_sz);
715	/* tell anybus we've consumed the message */
716	ind_ap ^= IND_AX_MOUT;
717	return write_ind_ap(cd->regmap, ind_ap);
718}
719
720static int task_fn_mbox(struct anybuss_host *cd, struct ab_task *t)
721{
722	struct mbox_priv *pd = &t->mbox_pd;
723	unsigned int ind_ap;
724	int ret;
725
726	if (!cd->power_on)
727		return -EIO;
728	regmap_read(cd->regmap, REG_IND_AP, &ind_ap);
729	if ((atomic_read(&cd->ind_ab) ^ ind_ap) & IND_AX_MIN) {
730		/* mbox input area busy */
731		if (time_after(jiffies, t->start_jiffies + TIMEOUT))
732			return -ETIMEDOUT;
733		return -EINPROGRESS;
734	}
735	/* write the header and msg to input area */
736	regmap_bulk_write(cd->regmap, MBOX_IN_AREA, &pd->hdr,
737			  sizeof(pd->hdr));
738	regmap_bulk_write(cd->regmap, MBOX_IN_AREA + sizeof(pd->hdr),
739			  pd->msg, pd->msg_out_sz);
740	/* tell anybus we gave it a message */
741	ind_ap ^= IND_AX_MIN;
742	ret = write_ind_ap(cd->regmap, ind_ap);
743	if (ret)
744		return ret;
745	t->start_jiffies = jiffies;
746	t->task_fn = task_fn_mbox_2;
747	return -EINPROGRESS;
748}
749
750static void log_invalid_other(struct device *dev,
751			      struct anybus_mbox_hdr *hdr)
752{
753	size_t ext_offs = ARRAY_SIZE(hdr->extended) - 1;
754	u16 code = be16_to_cpu(hdr->extended[ext_offs]);
755
756	dev_err(dev, "   Invalid other: [0x%02X]", code);
757}
758
759static const char * const EMSGS[] = {
760	"Invalid Message ID",
761	"Invalid Message Type",
762	"Invalid Command",
763	"Invalid Data Size",
764	"Message Header Malformed (offset 008h)",
765	"Message Header Malformed (offset 00Ah)",
766	"Message Header Malformed (offset 00Ch - 00Dh)",
767	"Invalid Address",
768	"Invalid Response",
769	"Flash Config Error",
770};
771
772static int mbox_cmd_err(struct device *dev, struct mbox_priv *mpriv)
773{
774	int i;
775	u8 ecode;
776	struct anybus_mbox_hdr *hdr = &mpriv->hdr;
777	u16 info = be16_to_cpu(hdr->info);
778	u8 *phdr = (u8 *)hdr;
779	u8 *pmsg = mpriv->msg;
780
781	if (!(info & 0x8000))
782		return 0;
783	ecode = (info >> 8) & 0x0F;
784	dev_err(dev, "mailbox command failed:");
785	if (ecode == 0x0F)
786		log_invalid_other(dev, hdr);
787	else if (ecode < ARRAY_SIZE(EMSGS))
788		dev_err(dev, "   Error code: %s (0x%02X)",
789			EMSGS[ecode], ecode);
790	else
791		dev_err(dev, "   Error code: 0x%02X\n", ecode);
792	dev_err(dev, "Failed command:");
793	dev_err(dev, "Message Header:");
794	for (i = 0; i < sizeof(mpriv->hdr); i += 2)
795		dev_err(dev, "%02X%02X", phdr[i], phdr[i + 1]);
796	dev_err(dev, "Message Data:");
797	for (i = 0; i < mpriv->msg_in_sz; i += 2)
798		dev_err(dev, "%02X%02X", pmsg[i], pmsg[i + 1]);
799	dev_err(dev, "Stack dump:");
800	dump_stack();
801	return -EIO;
802}
803
804static int _anybus_mbox_cmd(struct anybuss_host *cd,
805			    u16 cmd_num, bool is_fb_cmd,
806				const void *msg_out, size_t msg_out_sz,
807				void *msg_in, size_t msg_in_sz,
808				const void *ext, size_t ext_sz)
809{
810	struct ab_task *t;
811	struct mbox_priv *pd;
812	struct anybus_mbox_hdr *h;
813	size_t msg_sz = max(msg_in_sz, msg_out_sz);
814	u16 info;
815	int err;
816
817	if (msg_sz > MAX_MBOX_MSG_SZ)
818		return -EINVAL;
819	if (ext && ext_sz > sizeof(h->extended))
820		return -EINVAL;
821	t = ab_task_create_get(cd->qcache, task_fn_mbox);
822	if (!t)
823		return -ENOMEM;
824	pd = &t->mbox_pd;
825	h = &pd->hdr;
826	info = is_fb_cmd ? INFO_TYPE_FB : INFO_TYPE_APP;
827	/*
828	 * prevent uninitialized memory in the header from being sent
829	 * across the anybus
830	 */
831	memset(h, 0, sizeof(*h));
832	h->info = cpu_to_be16(info | INFO_COMMAND);
833	h->cmd_num = cpu_to_be16(cmd_num);
834	h->data_size = cpu_to_be16(msg_out_sz);
835	h->frame_count = cpu_to_be16(1);
836	h->frame_num = cpu_to_be16(1);
837	h->offset_high = cpu_to_be16(0);
838	h->offset_low = cpu_to_be16(0);
839	if (ext)
840		memcpy(h->extended, ext, ext_sz);
841	memcpy(pd->msg, msg_out, msg_out_sz);
842	pd->msg_out_sz = msg_out_sz;
843	pd->msg_in_sz = msg_in_sz;
844	err = ab_task_enqueue_wait(t, cd->powerq, &cd->qlock, &cd->wq);
845	if (err)
846		goto out;
847	/*
848	 * mailbox mechanism worked ok, but maybe the mbox response
849	 * contains an error ?
850	 */
851	err = mbox_cmd_err(cd->dev, pd);
852	if (err)
853		goto out;
854	memcpy(msg_in, pd->msg, msg_in_sz);
855out:
856	ab_task_put(t);
857	return err;
858}
859
860/* ------------------------ anybus queues ------------------------ */
861
862static void process_q(struct anybuss_host *cd, struct kfifo *q)
863{
864	struct ab_task *t;
865	int ret;
866
867	ret = kfifo_out_peek(q, &t, sizeof(t));
868	if (!ret)
869		return;
870	t->result = t->task_fn(cd, t);
871	if (t->result != -EINPROGRESS)
872		ab_task_dequeue_finish_put(q, cd);
873}
874
875static bool qs_have_work(struct kfifo *qs, size_t num)
876{
877	size_t i;
878	struct ab_task *t;
879	int ret;
880
881	for (i = 0; i < num; i++, qs++) {
882		ret = kfifo_out_peek(qs, &t, sizeof(t));
883		if (ret && (t->result != -EINPROGRESS))
884			return true;
885	}
886	return false;
887}
888
889static void process_qs(struct anybuss_host *cd)
890{
891	size_t i;
892	struct kfifo *qs = cd->qs;
893	size_t nqs = ARRAY_SIZE(cd->qs);
894
895	for (i = 0; i < nqs; i++, qs++)
896		process_q(cd, qs);
897}
898
899static void softint_ack(struct anybuss_host *cd)
900{
901	unsigned int ind_ap;
902
903	cd->softint_pending = false;
904	if (!cd->power_on)
905		return;
906	regmap_read(cd->regmap, REG_IND_AP, &ind_ap);
907	ind_ap &= ~IND_AX_EVNT;
908	ind_ap |= atomic_read(&cd->ind_ab) & IND_AX_EVNT;
909	write_ind_ap(cd->regmap, ind_ap);
910}
911
912static void process_softint(struct anybuss_host *cd)
913{
914	struct anybuss_client *client = cd->client;
915	static const u8 zero;
916	int ret;
917	unsigned int ind_ap, ev;
918	struct ab_task *t;
919
920	if (!cd->power_on)
921		return;
922	if (cd->softint_pending)
923		return;
924	regmap_read(cd->regmap, REG_IND_AP, &ind_ap);
925	if (!((atomic_read(&cd->ind_ab) ^ ind_ap) & IND_AX_EVNT))
926		return;
927	/* process software interrupt */
928	regmap_read(cd->regmap, REG_EVENT_CAUSE, &ev);
929	if (ev & EVENT_CAUSE_FBON) {
930		if (client->on_online_changed)
931			client->on_online_changed(client, true);
932		dev_dbg(cd->dev, "Fieldbus ON");
933	}
934	if (ev & EVENT_CAUSE_FBOF) {
935		if (client->on_online_changed)
936			client->on_online_changed(client, false);
937		dev_dbg(cd->dev, "Fieldbus OFF");
938	}
939	if (ev & EVENT_CAUSE_DC) {
940		if (client->on_area_updated)
941			client->on_area_updated(client);
942		dev_dbg(cd->dev, "Fieldbus data changed");
943	}
944	/*
945	 * reset the event cause bits.
946	 * this must be done while owning the fbctrl area, so we'll
947	 * enqueue a task to do that.
948	 */
949	t = create_area_writer(cd->qcache, IND_AX_FBCTRL,
950			       REG_EVENT_CAUSE, &zero, sizeof(zero));
951	if (!t) {
952		ret = -ENOMEM;
953		goto out;
954	}
955	t->done_fn = softint_ack;
956	ret = ab_task_enqueue(t, cd->powerq, &cd->qlock, &cd->wq);
957	ab_task_put(t);
958	cd->softint_pending = true;
959out:
960	WARN_ON(ret);
961	if (ret)
962		softint_ack(cd);
963}
964
965static int qthread_fn(void *data)
966{
967	struct anybuss_host *cd = data;
968	struct kfifo *qs = cd->qs;
969	size_t nqs = ARRAY_SIZE(cd->qs);
970	unsigned int ind_ab;
971
972	/*
973	 * this kernel thread has exclusive access to the anybus's memory.
974	 * only exception: the IND_AB register, which is accessed exclusively
975	 * by the interrupt service routine (ISR). This thread must not touch
976	 * the IND_AB register, but it does require access to its value.
977	 *
978	 * the interrupt service routine stores the register's value in
979	 * cd->ind_ab (an atomic_t), where we may safely access it, with the
980	 * understanding that it can be modified by the ISR at any time.
981	 */
982
983	while (!kthread_should_stop()) {
984		/*
985		 * make a local copy of IND_AB, so we can go around the loop
986		 * again in case it changed while processing queues and softint.
987		 */
988		ind_ab = atomic_read(&cd->ind_ab);
989		process_qs(cd);
990		process_softint(cd);
991		wait_event_timeout(cd->wq,
992				   (atomic_read(&cd->ind_ab) != ind_ab) ||
993				qs_have_work(qs, nqs) ||
994				kthread_should_stop(),
995			HZ);
996		/*
997		 * time out so even 'stuck' tasks will run eventually,
998		 * and can time out.
999		 */
1000	}
1001
1002	return 0;
1003}
1004
1005/* ------------------------ anybus exports ------------------------ */
1006
1007int anybuss_start_init(struct anybuss_client *client,
1008		       const struct anybuss_memcfg *cfg)
1009{
1010	int ret;
1011	u16 op_mode;
1012	struct anybuss_host *cd = client->host;
1013	struct msg_anybus_init msg = {
1014		.input_io_len = cpu_to_be16(cfg->input_io),
1015		.input_dpram_len = cpu_to_be16(cfg->input_dpram),
1016		.input_total_len = cpu_to_be16(cfg->input_total),
1017		.output_io_len = cpu_to_be16(cfg->output_io),
1018		.output_dpram_len = cpu_to_be16(cfg->output_dpram),
1019		.output_total_len = cpu_to_be16(cfg->output_total),
1020		.notif_config = cpu_to_be16(0x000F),
1021		.wd_val = cpu_to_be16(0),
1022	};
1023
1024	switch (cfg->offl_mode) {
1025	case FIELDBUS_DEV_OFFL_MODE_CLEAR:
1026		op_mode = 0;
1027		break;
1028	case FIELDBUS_DEV_OFFL_MODE_FREEZE:
1029		op_mode = OP_MODE_FBFC;
1030		break;
1031	case FIELDBUS_DEV_OFFL_MODE_SET:
1032		op_mode = OP_MODE_FBS;
1033		break;
1034	default:
1035		return -EINVAL;
1036	}
1037	msg.op_mode = cpu_to_be16(op_mode | OP_MODE_CD);
1038	ret = _anybus_mbox_cmd(cd, CMD_START_INIT, false, NULL, 0,
1039			       NULL, 0, NULL, 0);
1040	if (ret)
1041		return ret;
1042	return _anybus_mbox_cmd(cd, CMD_ANYBUS_INIT, false,
1043			&msg, sizeof(msg), NULL, 0, NULL, 0);
1044}
1045EXPORT_SYMBOL_GPL(anybuss_start_init);
1046
1047int anybuss_finish_init(struct anybuss_client *client)
1048{
1049	struct anybuss_host *cd = client->host;
1050
1051	return _anybus_mbox_cmd(cd, CMD_END_INIT, false, NULL, 0,
1052					NULL, 0, NULL, 0);
1053}
1054EXPORT_SYMBOL_GPL(anybuss_finish_init);
1055
1056int anybuss_read_fbctrl(struct anybuss_client *client, u16 addr,
1057			void *buf, size_t count)
1058{
1059	struct anybuss_host *cd = client->host;
1060	struct ab_task *t;
1061	int ret;
1062
1063	if (count == 0)
1064		return 0;
1065	if (!area_range_ok(addr, count, FBCTRL_AREA,
1066			   MAX_FBCTRL_AREA_SZ))
1067		return -EFAULT;
1068	t = create_area_reader(cd->qcache, IND_AX_FBCTRL, addr, count);
1069	if (!t)
1070		return -ENOMEM;
1071	ret = ab_task_enqueue_wait(t, cd->powerq, &cd->qlock, &cd->wq);
1072	if (ret)
1073		goto out;
1074	memcpy(buf, t->area_pd.buf, count);
1075out:
1076	ab_task_put(t);
1077	return ret;
1078}
1079EXPORT_SYMBOL_GPL(anybuss_read_fbctrl);
1080
1081int anybuss_write_input(struct anybuss_client *client,
1082			const char __user *buf, size_t size,
1083				loff_t *offset)
1084{
1085	ssize_t len = min_t(loff_t, MAX_DATA_AREA_SZ - *offset, size);
1086	struct anybuss_host *cd = client->host;
1087	struct ab_task *t;
1088	int ret;
1089
1090	if (len <= 0)
1091		return 0;
1092	t = create_area_user_writer(cd->qcache, IND_AX_IN,
1093				    DATA_IN_AREA + *offset, buf, len);
1094	if (IS_ERR(t))
1095		return PTR_ERR(t);
1096	ret = ab_task_enqueue_wait(t, cd->powerq, &cd->qlock, &cd->wq);
1097	ab_task_put(t);
1098	if (ret)
1099		return ret;
1100	/* success */
1101	*offset += len;
1102	return len;
1103}
1104EXPORT_SYMBOL_GPL(anybuss_write_input);
1105
1106int anybuss_read_output(struct anybuss_client *client,
1107			char __user *buf, size_t size,
1108				loff_t *offset)
1109{
1110	ssize_t len = min_t(loff_t, MAX_DATA_AREA_SZ - *offset, size);
1111	struct anybuss_host *cd = client->host;
1112	struct ab_task *t;
1113	int ret;
1114
1115	if (len <= 0)
1116		return 0;
1117	t = create_area_reader(cd->qcache, IND_AX_OUT,
1118			       DATA_OUT_AREA + *offset, len);
1119	if (!t)
1120		return -ENOMEM;
1121	ret = ab_task_enqueue_wait(t, cd->powerq, &cd->qlock, &cd->wq);
1122	if (ret)
1123		goto out;
1124	if (copy_to_user(buf, t->area_pd.buf, len))
1125		ret = -EFAULT;
1126out:
1127	ab_task_put(t);
1128	if (ret)
1129		return ret;
1130	/* success */
1131	*offset += len;
1132	return len;
1133}
1134EXPORT_SYMBOL_GPL(anybuss_read_output);
1135
1136int anybuss_send_msg(struct anybuss_client *client, u16 cmd_num,
1137		     const void *buf, size_t count)
1138{
1139	struct anybuss_host *cd = client->host;
1140
1141	return _anybus_mbox_cmd(cd, cmd_num, true, buf, count, NULL, 0,
1142					NULL, 0);
1143}
1144EXPORT_SYMBOL_GPL(anybuss_send_msg);
1145
1146int anybuss_send_ext(struct anybuss_client *client, u16 cmd_num,
1147		     const void *buf, size_t count)
1148{
1149	struct anybuss_host *cd = client->host;
1150
1151	return _anybus_mbox_cmd(cd, cmd_num, true, NULL, 0, NULL, 0,
1152					buf, count);
1153}
1154EXPORT_SYMBOL_GPL(anybuss_send_ext);
1155
1156int anybuss_recv_msg(struct anybuss_client *client, u16 cmd_num,
1157		     void *buf, size_t count)
1158{
1159	struct anybuss_host *cd = client->host;
1160
1161	return _anybus_mbox_cmd(cd, cmd_num, true, NULL, 0, buf, count,
1162					NULL, 0);
1163}
1164EXPORT_SYMBOL_GPL(anybuss_recv_msg);
1165
1166/* ------------------------ bus functions ------------------------ */
1167
1168static int anybus_bus_match(struct device *dev,
1169			    struct device_driver *drv)
1170{
1171	struct anybuss_client_driver *adrv =
1172		to_anybuss_client_driver(drv);
1173	struct anybuss_client *adev =
1174		to_anybuss_client(dev);
1175
1176	return adrv->anybus_id == be16_to_cpu(adev->anybus_id);
1177}
1178
1179static int anybus_bus_probe(struct device *dev)
1180{
1181	struct anybuss_client_driver *adrv =
1182		to_anybuss_client_driver(dev->driver);
1183	struct anybuss_client *adev =
1184		to_anybuss_client(dev);
1185
1186	return adrv->probe(adev);
1187}
1188
1189static void anybus_bus_remove(struct device *dev)
1190{
1191	struct anybuss_client_driver *adrv =
1192		to_anybuss_client_driver(dev->driver);
1193
1194	if (adrv->remove)
1195		adrv->remove(to_anybuss_client(dev));
1196}
1197
1198static const struct bus_type anybus_bus = {
1199	.name		= "anybuss",
1200	.match		= anybus_bus_match,
1201	.probe		= anybus_bus_probe,
1202	.remove		= anybus_bus_remove,
1203};
1204
1205int anybuss_client_driver_register(struct anybuss_client_driver *drv)
1206{
1207	if (!drv->probe)
1208		return -ENODEV;
1209
1210	drv->driver.bus = &anybus_bus;
1211	return driver_register(&drv->driver);
1212}
1213EXPORT_SYMBOL_GPL(anybuss_client_driver_register);
1214
1215void anybuss_client_driver_unregister(struct anybuss_client_driver *drv)
1216{
1217	return driver_unregister(&drv->driver);
1218}
1219EXPORT_SYMBOL_GPL(anybuss_client_driver_unregister);
1220
1221static void client_device_release(struct device *dev)
1222{
1223	kfree(to_anybuss_client(dev));
1224}
1225
1226static int taskq_alloc(struct device *dev, struct kfifo *q)
1227{
1228	void *buf;
1229	size_t size = 64 * sizeof(struct ab_task *);
1230
1231	buf = devm_kzalloc(dev, size, GFP_KERNEL);
1232	if (!buf)
1233		return -EIO;
1234	return kfifo_init(q, buf, size);
1235}
1236
1237static int anybus_of_get_host_idx(struct device_node *np)
1238{
1239	const __be32 *host_idx;
1240
1241	host_idx = of_get_address(np, 0, NULL, NULL);
1242	if (!host_idx)
1243		return -ENOENT;
1244	return __be32_to_cpu(*host_idx);
1245}
1246
1247static struct device_node *
1248anybus_of_find_child_device(struct device *dev, int host_idx)
1249{
1250	struct device_node *node;
1251
1252	if (!dev || !dev->of_node)
1253		return NULL;
1254	for_each_child_of_node(dev->of_node, node) {
1255		if (anybus_of_get_host_idx(node) == host_idx)
1256			return node;
1257	}
1258	return NULL;
1259}
1260
1261struct anybuss_host * __must_check
1262anybuss_host_common_probe(struct device *dev,
1263			  const struct anybuss_ops *ops)
1264{
1265	int ret, i;
1266	u8 val[4];
1267	__be16 fieldbus_type;
1268	struct anybuss_host *cd;
1269
1270	cd = devm_kzalloc(dev, sizeof(*cd), GFP_KERNEL);
1271	if (!cd)
1272		return ERR_PTR(-ENOMEM);
1273	cd->dev = dev;
1274	cd->host_idx = ops->host_idx;
1275	init_completion(&cd->card_boot);
1276	init_waitqueue_head(&cd->wq);
1277	for (i = 0; i < ARRAY_SIZE(cd->qs); i++) {
1278		ret = taskq_alloc(dev, &cd->qs[i]);
1279		if (ret)
1280			return ERR_PTR(ret);
1281	}
1282	if (WARN_ON(ARRAY_SIZE(cd->qs) < 3))
1283		return ERR_PTR(-EINVAL);
1284	cd->powerq = &cd->qs[0];
1285	cd->mboxq = &cd->qs[1];
1286	cd->areaq = &cd->qs[2];
1287	cd->reset = ops->reset;
1288	if (!cd->reset)
1289		return ERR_PTR(-EINVAL);
1290	cd->regmap = ops->regmap;
1291	if (!cd->regmap)
1292		return ERR_PTR(-EINVAL);
1293	spin_lock_init(&cd->qlock);
1294	cd->qcache = kmem_cache_create(dev_name(dev),
1295				       sizeof(struct ab_task), 0, 0, NULL);
1296	if (!cd->qcache)
1297		return ERR_PTR(-ENOMEM);
1298	cd->irq = ops->irq;
1299	if (cd->irq <= 0) {
1300		ret = -EINVAL;
1301		goto err_qcache;
1302	}
1303	/*
1304	 * use a dpram test to check if a card is present, this is only
1305	 * possible while in reset.
1306	 */
1307	reset_assert(cd);
1308	if (test_dpram(cd->regmap)) {
1309		dev_err(dev, "no Anybus-S card in slot");
1310		ret = -ENODEV;
1311		goto err_qcache;
1312	}
1313	ret = devm_request_threaded_irq(dev, cd->irq, NULL, irq_handler,
1314					IRQF_ONESHOT, dev_name(dev), cd);
1315	if (ret) {
1316		dev_err(dev, "could not request irq");
1317		goto err_qcache;
1318	}
1319	/*
1320	 * startup sequence:
1321	 *   a) perform dummy IND_AB read to prevent false 'init done' irq
1322	 *     (already done by test_dpram() above)
1323	 *   b) release reset
1324	 *   c) wait for first interrupt
1325	 *   d) interrupt came in: ready to go !
1326	 */
1327	reset_deassert(cd);
1328	if (!wait_for_completion_timeout(&cd->card_boot, TIMEOUT)) {
1329		ret = -ETIMEDOUT;
1330		goto err_reset;
1331	}
1332	/*
1333	 * according to the anybus docs, we're allowed to read these
1334	 * without handshaking / reserving the area
1335	 */
1336	dev_info(dev, "Anybus-S card detected");
1337	regmap_bulk_read(cd->regmap, REG_BOOTLOADER_V, val, 2);
1338	dev_info(dev, "Bootloader version: %02X%02X",
1339		 val[0], val[1]);
1340	regmap_bulk_read(cd->regmap, REG_API_V, val, 2);
1341	dev_info(dev, "API version: %02X%02X", val[0], val[1]);
1342	regmap_bulk_read(cd->regmap, REG_FIELDBUS_V, val, 2);
1343	dev_info(dev, "Fieldbus version: %02X%02X", val[0], val[1]);
1344	regmap_bulk_read(cd->regmap, REG_SERIAL_NO, val, 4);
1345	dev_info(dev, "Serial number: %02X%02X%02X%02X",
1346		 val[0], val[1], val[2], val[3]);
1347	add_device_randomness(&val, 4);
1348	regmap_bulk_read(cd->regmap, REG_FIELDBUS_TYPE, &fieldbus_type,
1349			 sizeof(fieldbus_type));
1350	dev_info(dev, "Fieldbus type: %04X", be16_to_cpu(fieldbus_type));
1351	regmap_bulk_read(cd->regmap, REG_MODULE_SW_V, val, 2);
1352	dev_info(dev, "Module SW version: %02X%02X",
1353		 val[0], val[1]);
1354	/* put card back reset until a client driver releases it */
1355	disable_irq(cd->irq);
1356	reset_assert(cd);
1357	atomic_set(&cd->ind_ab, IND_AB_UPDATED);
1358	/* fire up the queue thread */
1359	cd->qthread = kthread_run(qthread_fn, cd, dev_name(dev));
1360	if (IS_ERR(cd->qthread)) {
1361		dev_err(dev, "could not create kthread");
1362		ret = PTR_ERR(cd->qthread);
1363		goto err_reset;
1364	}
1365	/*
1366	 * now advertise that we've detected a client device (card).
1367	 * the bus infrastructure will match it to a client driver.
1368	 */
1369	cd->client = kzalloc(sizeof(*cd->client), GFP_KERNEL);
1370	if (!cd->client) {
1371		ret = -ENOMEM;
1372		goto err_kthread;
1373	}
1374	cd->client->anybus_id = fieldbus_type;
1375	cd->client->host = cd;
1376	cd->client->dev.bus = &anybus_bus;
1377	cd->client->dev.parent = dev;
1378	cd->client->dev.release = client_device_release;
1379	cd->client->dev.of_node =
1380		anybus_of_find_child_device(dev, cd->host_idx);
1381	dev_set_name(&cd->client->dev, "anybuss.card%d", cd->host_idx);
1382	ret = device_register(&cd->client->dev);
1383	if (ret)
1384		goto err_device;
1385	return cd;
1386err_device:
1387	put_device(&cd->client->dev);
1388err_kthread:
1389	kthread_stop(cd->qthread);
1390err_reset:
1391	reset_assert(cd);
1392err_qcache:
1393	kmem_cache_destroy(cd->qcache);
1394	return ERR_PTR(ret);
1395}
1396EXPORT_SYMBOL_GPL(anybuss_host_common_probe);
1397
1398void anybuss_host_common_remove(struct anybuss_host *host)
1399{
1400	struct anybuss_host *cd = host;
1401
1402	device_unregister(&cd->client->dev);
1403	kthread_stop(cd->qthread);
1404	reset_assert(cd);
1405	kmem_cache_destroy(cd->qcache);
1406}
1407EXPORT_SYMBOL_GPL(anybuss_host_common_remove);
1408
1409static void host_release(void *res)
1410{
1411	anybuss_host_common_remove(res);
1412}
1413
1414struct anybuss_host * __must_check
1415devm_anybuss_host_common_probe(struct device *dev,
1416			       const struct anybuss_ops *ops)
1417{
1418	struct anybuss_host *host;
1419	int ret;
1420
1421	host = anybuss_host_common_probe(dev, ops);
1422	if (IS_ERR(host))
1423		return host;
1424
1425	ret = devm_add_action_or_reset(dev, host_release, host);
1426	if (ret)
1427		return ERR_PTR(ret);
1428
1429	return host;
1430}
1431EXPORT_SYMBOL_GPL(devm_anybuss_host_common_probe);
1432
1433static int __init anybus_init(void)
1434{
1435	int ret;
1436
1437	ret = bus_register(&anybus_bus);
1438	if (ret)
1439		pr_err("could not register Anybus-S bus: %d\n", ret);
1440	return ret;
1441}
1442module_init(anybus_init);
1443
1444static void __exit anybus_exit(void)
1445{
1446	bus_unregister(&anybus_bus);
1447}
1448module_exit(anybus_exit);
1449
1450MODULE_DESCRIPTION("HMS Anybus-S Host Driver");
1451MODULE_AUTHOR("Sven Van Asbroeck <TheSven73@gmail.com>");
1452MODULE_LICENSE("GPL v2");
1453