1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * linux/drivers/mmc/core/sdio_irq.c
4 *
5 * Author:      Nicolas Pitre
6 * Created:     June 18, 2007
7 * Copyright:   MontaVista Software Inc.
8 *
9 * Copyright 2008 Pierre Ossman
10 */
11
12#include <linux/kernel.h>
13#include <linux/sched.h>
14#include <uapi/linux/sched/types.h>
15#include <linux/kthread.h>
16#include <linux/export.h>
17#include <linux/wait.h>
18#include <linux/delay.h>
19
20#include <linux/mmc/core.h>
21#include <linux/mmc/host.h>
22#include <linux/mmc/card.h>
23#include <linux/mmc/sdio.h>
24#include <linux/mmc/sdio_func.h>
25
26#include "sdio_ops.h"
27#include "core.h"
28#include "card.h"
29
30static int sdio_get_pending_irqs(struct mmc_host *host, u8 *pending)
31{
32	struct mmc_card *card = host->card;
33	int ret;
34
35	WARN_ON(!host->claimed);
36
37	ret = mmc_io_rw_direct(card, 0, 0, SDIO_CCCR_INTx, 0, pending);
38	if (ret) {
39		pr_debug("%s: error %d reading SDIO_CCCR_INTx\n",
40		       mmc_card_id(card), ret);
41		return ret;
42	}
43
44	if (*pending && mmc_card_broken_irq_polling(card) &&
45	    !(host->caps & MMC_CAP_SDIO_IRQ)) {
46		unsigned char dummy;
47
48		/* A fake interrupt could be created when we poll SDIO_CCCR_INTx
49		 * register with a Marvell SD8797 card. A dummy CMD52 read to
50		 * function 0 register 0xff can avoid this.
51		 */
52		mmc_io_rw_direct(card, 0, 0, 0xff, 0, &dummy);
53	}
54
55	return 0;
56}
57
58static int process_sdio_pending_irqs(struct mmc_host *host)
59{
60	struct mmc_card *card = host->card;
61	int i, ret, count;
62	bool sdio_irq_pending = host->sdio_irq_pending;
63	unsigned char pending;
64	struct sdio_func *func;
65
66	/* Don't process SDIO IRQs if the card is suspended. */
67	if (mmc_card_suspended(card))
68		return 0;
69
70	/* Clear the flag to indicate that we have processed the IRQ. */
71	host->sdio_irq_pending = false;
72
73	/*
74	 * Optimization, if there is only 1 function interrupt registered
75	 * and we know an IRQ was signaled then call irq handler directly.
76	 * Otherwise do the full probe.
77	 */
78	func = card->sdio_single_irq;
79	if (func && sdio_irq_pending) {
80		func->irq_handler(func);
81		return 1;
82	}
83
84	ret = sdio_get_pending_irqs(host, &pending);
85	if (ret)
86		return ret;
87
88	count = 0;
89	for (i = 1; i <= 7; i++) {
90		if (pending & (1 << i)) {
91			func = card->sdio_func[i - 1];
92			if (!func) {
93				pr_warn("%s: pending IRQ for non-existent function\n",
94					mmc_card_id(card));
95				ret = -EINVAL;
96			} else if (func->irq_handler) {
97				func->irq_handler(func);
98				count++;
99			} else {
100				pr_warn("%s: pending IRQ with no handler\n",
101					sdio_func_id(func));
102				ret = -EINVAL;
103			}
104		}
105	}
106
107	if (count)
108		return count;
109
110	return ret;
111}
112
113static void sdio_run_irqs(struct mmc_host *host)
114{
115	mmc_claim_host(host);
116	if (host->sdio_irqs) {
117		process_sdio_pending_irqs(host);
118		if (!host->sdio_irq_pending)
119			host->ops->ack_sdio_irq(host);
120	}
121	mmc_release_host(host);
122}
123
124void sdio_irq_work(struct work_struct *work)
125{
126	struct mmc_host *host =
127		container_of(work, struct mmc_host, sdio_irq_work);
128
129	sdio_run_irqs(host);
130}
131
132void sdio_signal_irq(struct mmc_host *host)
133{
134	host->sdio_irq_pending = true;
135	schedule_work(&host->sdio_irq_work);
136}
137EXPORT_SYMBOL_GPL(sdio_signal_irq);
138
139static int sdio_irq_thread(void *_host)
140{
141	struct mmc_host *host = _host;
142	unsigned long period, idle_period;
143	int ret;
144
145	sched_set_fifo_low(current);
146
147	/*
148	 * We want to allow for SDIO cards to work even on non SDIO
149	 * aware hosts.  One thing that non SDIO host cannot do is
150	 * asynchronous notification of pending SDIO card interrupts
151	 * hence we poll for them in that case.
152	 */
153	idle_period = msecs_to_jiffies(10);
154	period = (host->caps & MMC_CAP_SDIO_IRQ) ?
155		MAX_SCHEDULE_TIMEOUT : idle_period;
156
157	pr_debug("%s: IRQ thread started (poll period = %lu jiffies)\n",
158		 mmc_hostname(host), period);
159
160	do {
161		/*
162		 * We claim the host here on drivers behalf for a couple
163		 * reasons:
164		 *
165		 * 1) it is already needed to retrieve the CCCR_INTx;
166		 * 2) we want the driver(s) to clear the IRQ condition ASAP;
167		 * 3) we need to control the abort condition locally.
168		 *
169		 * Just like traditional hard IRQ handlers, we expect SDIO
170		 * IRQ handlers to be quick and to the point, so that the
171		 * holding of the host lock does not cover too much work
172		 * that doesn't require that lock to be held.
173		 */
174		ret = __mmc_claim_host(host, NULL,
175				       &host->sdio_irq_thread_abort);
176		if (ret)
177			break;
178		ret = process_sdio_pending_irqs(host);
179		mmc_release_host(host);
180
181		/*
182		 * Give other threads a chance to run in the presence of
183		 * errors.
184		 */
185		if (ret < 0) {
186			set_current_state(TASK_INTERRUPTIBLE);
187			if (!kthread_should_stop())
188				schedule_timeout(HZ);
189			set_current_state(TASK_RUNNING);
190		}
191
192		/*
193		 * Adaptive polling frequency based on the assumption
194		 * that an interrupt will be closely followed by more.
195		 * This has a substantial benefit for network devices.
196		 */
197		if (!(host->caps & MMC_CAP_SDIO_IRQ)) {
198			if (ret > 0)
199				period /= 2;
200			else {
201				period++;
202				if (period > idle_period)
203					period = idle_period;
204			}
205		}
206
207		set_current_state(TASK_INTERRUPTIBLE);
208		if (host->caps & MMC_CAP_SDIO_IRQ)
209			host->ops->enable_sdio_irq(host, 1);
210		if (!kthread_should_stop())
211			schedule_timeout(period);
212		set_current_state(TASK_RUNNING);
213	} while (!kthread_should_stop());
214
215	if (host->caps & MMC_CAP_SDIO_IRQ)
216		host->ops->enable_sdio_irq(host, 0);
217
218	pr_debug("%s: IRQ thread exiting with code %d\n",
219		 mmc_hostname(host), ret);
220
221	return ret;
222}
223
224static int sdio_card_irq_get(struct mmc_card *card)
225{
226	struct mmc_host *host = card->host;
227
228	WARN_ON(!host->claimed);
229
230	if (!host->sdio_irqs++) {
231		if (!(host->caps2 & MMC_CAP2_SDIO_IRQ_NOTHREAD)) {
232			atomic_set(&host->sdio_irq_thread_abort, 0);
233			host->sdio_irq_thread =
234				kthread_run(sdio_irq_thread, host,
235					    "ksdioirqd/%s", mmc_hostname(host));
236			if (IS_ERR(host->sdio_irq_thread)) {
237				int err = PTR_ERR(host->sdio_irq_thread);
238				host->sdio_irqs--;
239				return err;
240			}
241		} else if (host->caps & MMC_CAP_SDIO_IRQ) {
242			host->ops->enable_sdio_irq(host, 1);
243		}
244	}
245
246	return 0;
247}
248
249static int sdio_card_irq_put(struct mmc_card *card)
250{
251	struct mmc_host *host = card->host;
252
253	WARN_ON(!host->claimed);
254
255	if (host->sdio_irqs < 1)
256		return -EINVAL;
257
258	if (!--host->sdio_irqs) {
259		if (!(host->caps2 & MMC_CAP2_SDIO_IRQ_NOTHREAD)) {
260			atomic_set(&host->sdio_irq_thread_abort, 1);
261			kthread_stop(host->sdio_irq_thread);
262		} else if (host->caps & MMC_CAP_SDIO_IRQ) {
263			host->ops->enable_sdio_irq(host, 0);
264		}
265	}
266
267	return 0;
268}
269
270/* If there is only 1 function registered set sdio_single_irq */
271static void sdio_single_irq_set(struct mmc_card *card)
272{
273	struct sdio_func *func;
274	int i;
275
276	card->sdio_single_irq = NULL;
277	if ((card->host->caps & MMC_CAP_SDIO_IRQ) &&
278	    card->host->sdio_irqs == 1) {
279		for (i = 0; i < card->sdio_funcs; i++) {
280			func = card->sdio_func[i];
281			if (func && func->irq_handler) {
282				card->sdio_single_irq = func;
283				break;
284			}
285		}
286	}
287}
288
289/**
290 *	sdio_claim_irq - claim the IRQ for a SDIO function
291 *	@func: SDIO function
292 *	@handler: IRQ handler callback
293 *
294 *	Claim and activate the IRQ for the given SDIO function. The provided
295 *	handler will be called when that IRQ is asserted.  The host is always
296 *	claimed already when the handler is called so the handler should not
297 *	call sdio_claim_host() or sdio_release_host().
298 */
299int sdio_claim_irq(struct sdio_func *func, sdio_irq_handler_t *handler)
300{
301	int ret;
302	unsigned char reg;
303
304	if (!func)
305		return -EINVAL;
306
307	pr_debug("SDIO: Enabling IRQ for %s...\n", sdio_func_id(func));
308
309	if (func->irq_handler) {
310		pr_debug("SDIO: IRQ for %s already in use.\n", sdio_func_id(func));
311		return -EBUSY;
312	}
313
314	ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, &reg);
315	if (ret)
316		return ret;
317
318	reg |= 1 << func->num;
319
320	reg |= 1; /* Master interrupt enable */
321
322	ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL);
323	if (ret)
324		return ret;
325
326	func->irq_handler = handler;
327	ret = sdio_card_irq_get(func->card);
328	if (ret)
329		func->irq_handler = NULL;
330	sdio_single_irq_set(func->card);
331
332	return ret;
333}
334EXPORT_SYMBOL_GPL(sdio_claim_irq);
335
336/**
337 *	sdio_release_irq - release the IRQ for a SDIO function
338 *	@func: SDIO function
339 *
340 *	Disable and release the IRQ for the given SDIO function.
341 */
342int sdio_release_irq(struct sdio_func *func)
343{
344	int ret;
345	unsigned char reg;
346
347	if (!func)
348		return -EINVAL;
349
350	pr_debug("SDIO: Disabling IRQ for %s...\n", sdio_func_id(func));
351
352	if (func->irq_handler) {
353		func->irq_handler = NULL;
354		sdio_card_irq_put(func->card);
355		sdio_single_irq_set(func->card);
356	}
357
358	ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, &reg);
359	if (ret)
360		return ret;
361
362	reg &= ~(1 << func->num);
363
364	/* Disable master interrupt with the last function interrupt */
365	if (!(reg & 0xFE))
366		reg = 0;
367
368	ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL);
369	if (ret)
370		return ret;
371
372	return 0;
373}
374EXPORT_SYMBOL_GPL(sdio_release_irq);
375
376