xref: /openbmc/linux/drivers/mmc/core/sdio_irq.c (revision b8d312aa) 
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 
30 static int process_sdio_pending_irqs(struct mmc_host *host)
31 {
32 	struct mmc_card *card = host->card;
33 	int i, ret, count;
34 	unsigned char pending;
35 	struct sdio_func *func;
36 
37 	/* Don't process SDIO IRQs if the card is suspended. */
38 	if (mmc_card_suspended(card))
39 		return 0;
40 
41 	/*
42 	 * Optimization, if there is only 1 function interrupt registered
43 	 * and we know an IRQ was signaled then call irq handler directly.
44 	 * Otherwise do the full probe.
45 	 */
46 	func = card->sdio_single_irq;
47 	if (func && host->sdio_irq_pending) {
48 		func->irq_handler(func);
49 		return 1;
50 	}
51 
52 	ret = mmc_io_rw_direct(card, 0, 0, SDIO_CCCR_INTx, 0, &pending);
53 	if (ret) {
54 		pr_debug("%s: error %d reading SDIO_CCCR_INTx\n",
55 		       mmc_card_id(card), ret);
56 		return ret;
57 	}
58 
59 	if (pending && mmc_card_broken_irq_polling(card) &&
60 	    !(host->caps & MMC_CAP_SDIO_IRQ)) {
61 		unsigned char dummy;
62 
63 		/* A fake interrupt could be created when we poll SDIO_CCCR_INTx
64 		 * register with a Marvell SD8797 card. A dummy CMD52 read to
65 		 * function 0 register 0xff can avoid this.
66 		 */
67 		mmc_io_rw_direct(card, 0, 0, 0xff, 0, &dummy);
68 	}
69 
70 	count = 0;
71 	for (i = 1; i <= 7; i++) {
72 		if (pending & (1 << i)) {
73 			func = card->sdio_func[i - 1];
74 			if (!func) {
75 				pr_warn("%s: pending IRQ for non-existent function\n",
76 					mmc_card_id(card));
77 				ret = -EINVAL;
78 			} else if (func->irq_handler) {
79 				func->irq_handler(func);
80 				count++;
81 			} else {
82 				pr_warn("%s: pending IRQ with no handler\n",
83 					sdio_func_id(func));
84 				ret = -EINVAL;
85 			}
86 		}
87 	}
88 
89 	if (count)
90 		return count;
91 
92 	return ret;
93 }
94 
95 static void sdio_run_irqs(struct mmc_host *host)
96 {
97 	mmc_claim_host(host);
98 	if (host->sdio_irqs) {
99 		host->sdio_irq_pending = true;
100 		process_sdio_pending_irqs(host);
101 		if (host->ops->ack_sdio_irq)
102 			host->ops->ack_sdio_irq(host);
103 	}
104 	mmc_release_host(host);
105 }
106 
107 void sdio_irq_work(struct work_struct *work)
108 {
109 	struct mmc_host *host =
110 		container_of(work, struct mmc_host, sdio_irq_work.work);
111 
112 	sdio_run_irqs(host);
113 }
114 
115 void sdio_signal_irq(struct mmc_host *host)
116 {
117 	queue_delayed_work(system_wq, &host->sdio_irq_work, 0);
118 }
119 EXPORT_SYMBOL_GPL(sdio_signal_irq);
120 
121 static int sdio_irq_thread(void *_host)
122 {
123 	struct mmc_host *host = _host;
124 	struct sched_param param = { .sched_priority = 1 };
125 	unsigned long period, idle_period;
126 	int ret;
127 
128 	sched_setscheduler(current, SCHED_FIFO, &param);
129 
130 	/*
131 	 * We want to allow for SDIO cards to work even on non SDIO
132 	 * aware hosts.  One thing that non SDIO host cannot do is
133 	 * asynchronous notification of pending SDIO card interrupts
134 	 * hence we poll for them in that case.
135 	 */
136 	idle_period = msecs_to_jiffies(10);
137 	period = (host->caps & MMC_CAP_SDIO_IRQ) ?
138 		MAX_SCHEDULE_TIMEOUT : idle_period;
139 
140 	pr_debug("%s: IRQ thread started (poll period = %lu jiffies)\n",
141 		 mmc_hostname(host), period);
142 
143 	do {
144 		/*
145 		 * We claim the host here on drivers behalf for a couple
146 		 * reasons:
147 		 *
148 		 * 1) it is already needed to retrieve the CCCR_INTx;
149 		 * 2) we want the driver(s) to clear the IRQ condition ASAP;
150 		 * 3) we need to control the abort condition locally.
151 		 *
152 		 * Just like traditional hard IRQ handlers, we expect SDIO
153 		 * IRQ handlers to be quick and to the point, so that the
154 		 * holding of the host lock does not cover too much work
155 		 * that doesn't require that lock to be held.
156 		 */
157 		ret = __mmc_claim_host(host, NULL,
158 				       &host->sdio_irq_thread_abort);
159 		if (ret)
160 			break;
161 		ret = process_sdio_pending_irqs(host);
162 		host->sdio_irq_pending = false;
163 		mmc_release_host(host);
164 
165 		/*
166 		 * Give other threads a chance to run in the presence of
167 		 * errors.
168 		 */
169 		if (ret < 0) {
170 			set_current_state(TASK_INTERRUPTIBLE);
171 			if (!kthread_should_stop())
172 				schedule_timeout(HZ);
173 			set_current_state(TASK_RUNNING);
174 		}
175 
176 		/*
177 		 * Adaptive polling frequency based on the assumption
178 		 * that an interrupt will be closely followed by more.
179 		 * This has a substantial benefit for network devices.
180 		 */
181 		if (!(host->caps & MMC_CAP_SDIO_IRQ)) {
182 			if (ret > 0)
183 				period /= 2;
184 			else {
185 				period++;
186 				if (period > idle_period)
187 					period = idle_period;
188 			}
189 		}
190 
191 		set_current_state(TASK_INTERRUPTIBLE);
192 		if (host->caps & MMC_CAP_SDIO_IRQ)
193 			host->ops->enable_sdio_irq(host, 1);
194 		if (!kthread_should_stop())
195 			schedule_timeout(period);
196 		set_current_state(TASK_RUNNING);
197 	} while (!kthread_should_stop());
198 
199 	if (host->caps & MMC_CAP_SDIO_IRQ)
200 		host->ops->enable_sdio_irq(host, 0);
201 
202 	pr_debug("%s: IRQ thread exiting with code %d\n",
203 		 mmc_hostname(host), ret);
204 
205 	return ret;
206 }
207 
208 static int sdio_card_irq_get(struct mmc_card *card)
209 {
210 	struct mmc_host *host = card->host;
211 
212 	WARN_ON(!host->claimed);
213 
214 	if (!host->sdio_irqs++) {
215 		if (!(host->caps2 & MMC_CAP2_SDIO_IRQ_NOTHREAD)) {
216 			atomic_set(&host->sdio_irq_thread_abort, 0);
217 			host->sdio_irq_thread =
218 				kthread_run(sdio_irq_thread, host,
219 					    "ksdioirqd/%s", mmc_hostname(host));
220 			if (IS_ERR(host->sdio_irq_thread)) {
221 				int err = PTR_ERR(host->sdio_irq_thread);
222 				host->sdio_irqs--;
223 				return err;
224 			}
225 		} else if (host->caps & MMC_CAP_SDIO_IRQ) {
226 			host->ops->enable_sdio_irq(host, 1);
227 		}
228 	}
229 
230 	return 0;
231 }
232 
233 static int sdio_card_irq_put(struct mmc_card *card)
234 {
235 	struct mmc_host *host = card->host;
236 
237 	WARN_ON(!host->claimed);
238 
239 	if (host->sdio_irqs < 1)
240 		return -EINVAL;
241 
242 	if (!--host->sdio_irqs) {
243 		if (!(host->caps2 & MMC_CAP2_SDIO_IRQ_NOTHREAD)) {
244 			atomic_set(&host->sdio_irq_thread_abort, 1);
245 			kthread_stop(host->sdio_irq_thread);
246 		} else if (host->caps & MMC_CAP_SDIO_IRQ) {
247 			host->ops->enable_sdio_irq(host, 0);
248 		}
249 	}
250 
251 	return 0;
252 }
253 
254 /* If there is only 1 function registered set sdio_single_irq */
255 static void sdio_single_irq_set(struct mmc_card *card)
256 {
257 	struct sdio_func *func;
258 	int i;
259 
260 	card->sdio_single_irq = NULL;
261 	if ((card->host->caps & MMC_CAP_SDIO_IRQ) &&
262 	    card->host->sdio_irqs == 1)
263 		for (i = 0; i < card->sdio_funcs; i++) {
264 		       func = card->sdio_func[i];
265 		       if (func && func->irq_handler) {
266 			       card->sdio_single_irq = func;
267 			       break;
268 		       }
269 	       }
270 }
271 
272 /**
273  *	sdio_claim_irq - claim the IRQ for a SDIO function
274  *	@func: SDIO function
275  *	@handler: IRQ handler callback
276  *
277  *	Claim and activate the IRQ for the given SDIO function. The provided
278  *	handler will be called when that IRQ is asserted.  The host is always
279  *	claimed already when the handler is called so the handler should not
280  *	call sdio_claim_host() or sdio_release_host().
281  */
282 int sdio_claim_irq(struct sdio_func *func, sdio_irq_handler_t *handler)
283 {
284 	int ret;
285 	unsigned char reg;
286 
287 	if (!func)
288 		return -EINVAL;
289 
290 	pr_debug("SDIO: Enabling IRQ for %s...\n", sdio_func_id(func));
291 
292 	if (func->irq_handler) {
293 		pr_debug("SDIO: IRQ for %s already in use.\n", sdio_func_id(func));
294 		return -EBUSY;
295 	}
296 
297 	ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, &reg);
298 	if (ret)
299 		return ret;
300 
301 	reg |= 1 << func->num;
302 
303 	reg |= 1; /* Master interrupt enable */
304 
305 	ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL);
306 	if (ret)
307 		return ret;
308 
309 	func->irq_handler = handler;
310 	ret = sdio_card_irq_get(func->card);
311 	if (ret)
312 		func->irq_handler = NULL;
313 	sdio_single_irq_set(func->card);
314 
315 	return ret;
316 }
317 EXPORT_SYMBOL_GPL(sdio_claim_irq);
318 
319 /**
320  *	sdio_release_irq - release the IRQ for a SDIO function
321  *	@func: SDIO function
322  *
323  *	Disable and release the IRQ for the given SDIO function.
324  */
325 int sdio_release_irq(struct sdio_func *func)
326 {
327 	int ret;
328 	unsigned char reg;
329 
330 	if (!func)
331 		return -EINVAL;
332 
333 	pr_debug("SDIO: Disabling IRQ for %s...\n", sdio_func_id(func));
334 
335 	if (func->irq_handler) {
336 		func->irq_handler = NULL;
337 		sdio_card_irq_put(func->card);
338 		sdio_single_irq_set(func->card);
339 	}
340 
341 	ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, &reg);
342 	if (ret)
343 		return ret;
344 
345 	reg &= ~(1 << func->num);
346 
347 	/* Disable master interrupt with the last function interrupt */
348 	if (!(reg & 0xFE))
349 		reg = 0;
350 
351 	ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL);
352 	if (ret)
353 		return ret;
354 
355 	return 0;
356 }
357 EXPORT_SYMBOL_GPL(sdio_release_irq);
358 
359