xref: /linux/drivers/mmc/core/sdio_irq.c (revision 8c749ce93ee69e789e46b3be98de9e0cbfcf8ed8) 
1 /*
2  * linux/drivers/mmc/core/sdio_irq.c
3  *
4  * Author:      Nicolas Pitre
5  * Created:     June 18, 2007
6  * Copyright:   MontaVista Software Inc.
7  *
8  * Copyright 2008 Pierre Ossman
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License as published by
12  * the Free Software Foundation; either version 2 of the License, or (at
13  * your option) any later version.
14  */
15 
16 #include <linux/kernel.h>
17 #include <linux/sched.h>
18 #include <linux/kthread.h>
19 #include <linux/export.h>
20 #include <linux/wait.h>
21 #include <linux/delay.h>
22 
23 #include <linux/mmc/core.h>
24 #include <linux/mmc/host.h>
25 #include <linux/mmc/card.h>
26 #include <linux/mmc/sdio.h>
27 #include <linux/mmc/sdio_func.h>
28 
29 #include "sdio_ops.h"
30 
31 static int process_sdio_pending_irqs(struct mmc_host *host)
32 {
33 	struct mmc_card *card = host->card;
34 	int i, ret, count;
35 	unsigned char pending;
36 	struct sdio_func *func;
37 
38 	/*
39 	 * Optimization, if there is only 1 function interrupt registered
40 	 * and we know an IRQ was signaled then call irq handler directly.
41 	 * Otherwise do the full probe.
42 	 */
43 	func = card->sdio_single_irq;
44 	if (func && host->sdio_irq_pending) {
45 		func->irq_handler(func);
46 		return 1;
47 	}
48 
49 	ret = mmc_io_rw_direct(card, 0, 0, SDIO_CCCR_INTx, 0, &pending);
50 	if (ret) {
51 		pr_debug("%s: error %d reading SDIO_CCCR_INTx\n",
52 		       mmc_card_id(card), ret);
53 		return ret;
54 	}
55 
56 	if (pending && mmc_card_broken_irq_polling(card) &&
57 	    !(host->caps & MMC_CAP_SDIO_IRQ)) {
58 		unsigned char dummy;
59 
60 		/* A fake interrupt could be created when we poll SDIO_CCCR_INTx
61 		 * register with a Marvell SD8797 card. A dummy CMD52 read to
62 		 * function 0 register 0xff can avoid this.
63 		 */
64 		mmc_io_rw_direct(card, 0, 0, 0xff, 0, &dummy);
65 	}
66 
67 	count = 0;
68 	for (i = 1; i <= 7; i++) {
69 		if (pending & (1 << i)) {
70 			func = card->sdio_func[i - 1];
71 			if (!func) {
72 				pr_warn("%s: pending IRQ for non-existent function\n",
73 					mmc_card_id(card));
74 				ret = -EINVAL;
75 			} else if (func->irq_handler) {
76 				func->irq_handler(func);
77 				count++;
78 			} else {
79 				pr_warn("%s: pending IRQ with no handler\n",
80 					sdio_func_id(func));
81 				ret = -EINVAL;
82 			}
83 		}
84 	}
85 
86 	if (count)
87 		return count;
88 
89 	return ret;
90 }
91 
92 void sdio_run_irqs(struct mmc_host *host)
93 {
94 	mmc_claim_host(host);
95 	host->sdio_irq_pending = true;
96 	process_sdio_pending_irqs(host);
97 	mmc_release_host(host);
98 }
99 EXPORT_SYMBOL_GPL(sdio_run_irqs);
100 
101 static int sdio_irq_thread(void *_host)
102 {
103 	struct mmc_host *host = _host;
104 	struct sched_param param = { .sched_priority = 1 };
105 	unsigned long period, idle_period;
106 	int ret;
107 
108 	sched_setscheduler(current, SCHED_FIFO, &param);
109 
110 	/*
111 	 * We want to allow for SDIO cards to work even on non SDIO
112 	 * aware hosts.  One thing that non SDIO host cannot do is
113 	 * asynchronous notification of pending SDIO card interrupts
114 	 * hence we poll for them in that case.
115 	 */
116 	idle_period = msecs_to_jiffies(10);
117 	period = (host->caps & MMC_CAP_SDIO_IRQ) ?
118 		MAX_SCHEDULE_TIMEOUT : idle_period;
119 
120 	pr_debug("%s: IRQ thread started (poll period = %lu jiffies)\n",
121 		 mmc_hostname(host), period);
122 
123 	do {
124 		/*
125 		 * We claim the host here on drivers behalf for a couple
126 		 * reasons:
127 		 *
128 		 * 1) it is already needed to retrieve the CCCR_INTx;
129 		 * 2) we want the driver(s) to clear the IRQ condition ASAP;
130 		 * 3) we need to control the abort condition locally.
131 		 *
132 		 * Just like traditional hard IRQ handlers, we expect SDIO
133 		 * IRQ handlers to be quick and to the point, so that the
134 		 * holding of the host lock does not cover too much work
135 		 * that doesn't require that lock to be held.
136 		 */
137 		ret = __mmc_claim_host(host, &host->sdio_irq_thread_abort);
138 		if (ret)
139 			break;
140 		ret = process_sdio_pending_irqs(host);
141 		host->sdio_irq_pending = false;
142 		mmc_release_host(host);
143 
144 		/*
145 		 * Give other threads a chance to run in the presence of
146 		 * errors.
147 		 */
148 		if (ret < 0) {
149 			set_current_state(TASK_INTERRUPTIBLE);
150 			if (!kthread_should_stop())
151 				schedule_timeout(HZ);
152 			set_current_state(TASK_RUNNING);
153 		}
154 
155 		/*
156 		 * Adaptive polling frequency based on the assumption
157 		 * that an interrupt will be closely followed by more.
158 		 * This has a substantial benefit for network devices.
159 		 */
160 		if (!(host->caps & MMC_CAP_SDIO_IRQ)) {
161 			if (ret > 0)
162 				period /= 2;
163 			else {
164 				period++;
165 				if (period > idle_period)
166 					period = idle_period;
167 			}
168 		}
169 
170 		set_current_state(TASK_INTERRUPTIBLE);
171 		if (host->caps & MMC_CAP_SDIO_IRQ)
172 			host->ops->enable_sdio_irq(host, 1);
173 		if (!kthread_should_stop())
174 			schedule_timeout(period);
175 		set_current_state(TASK_RUNNING);
176 	} while (!kthread_should_stop());
177 
178 	if (host->caps & MMC_CAP_SDIO_IRQ)
179 		host->ops->enable_sdio_irq(host, 0);
180 
181 	pr_debug("%s: IRQ thread exiting with code %d\n",
182 		 mmc_hostname(host), ret);
183 
184 	return ret;
185 }
186 
187 static int sdio_card_irq_get(struct mmc_card *card)
188 {
189 	struct mmc_host *host = card->host;
190 
191 	WARN_ON(!host->claimed);
192 
193 	if (!host->sdio_irqs++) {
194 		if (!(host->caps2 & MMC_CAP2_SDIO_IRQ_NOTHREAD)) {
195 			atomic_set(&host->sdio_irq_thread_abort, 0);
196 			host->sdio_irq_thread =
197 				kthread_run(sdio_irq_thread, host,
198 					    "ksdioirqd/%s", mmc_hostname(host));
199 			if (IS_ERR(host->sdio_irq_thread)) {
200 				int err = PTR_ERR(host->sdio_irq_thread);
201 				host->sdio_irqs--;
202 				return err;
203 			}
204 		} else if (host->caps & MMC_CAP_SDIO_IRQ) {
205 			host->ops->enable_sdio_irq(host, 1);
206 		}
207 	}
208 
209 	return 0;
210 }
211 
212 static int sdio_card_irq_put(struct mmc_card *card)
213 {
214 	struct mmc_host *host = card->host;
215 
216 	WARN_ON(!host->claimed);
217 	BUG_ON(host->sdio_irqs < 1);
218 
219 	if (!--host->sdio_irqs) {
220 		if (!(host->caps2 & MMC_CAP2_SDIO_IRQ_NOTHREAD)) {
221 			atomic_set(&host->sdio_irq_thread_abort, 1);
222 			kthread_stop(host->sdio_irq_thread);
223 		} else if (host->caps & MMC_CAP_SDIO_IRQ) {
224 			host->ops->enable_sdio_irq(host, 0);
225 		}
226 	}
227 
228 	return 0;
229 }
230 
231 /* If there is only 1 function registered set sdio_single_irq */
232 static void sdio_single_irq_set(struct mmc_card *card)
233 {
234 	struct sdio_func *func;
235 	int i;
236 
237 	card->sdio_single_irq = NULL;
238 	if ((card->host->caps & MMC_CAP_SDIO_IRQ) &&
239 	    card->host->sdio_irqs == 1)
240 		for (i = 0; i < card->sdio_funcs; i++) {
241 		       func = card->sdio_func[i];
242 		       if (func && func->irq_handler) {
243 			       card->sdio_single_irq = func;
244 			       break;
245 		       }
246 	       }
247 }
248 
249 /**
250  *	sdio_claim_irq - claim the IRQ for a SDIO function
251  *	@func: SDIO function
252  *	@handler: IRQ handler callback
253  *
254  *	Claim and activate the IRQ for the given SDIO function. The provided
255  *	handler will be called when that IRQ is asserted.  The host is always
256  *	claimed already when the handler is called so the handler must not
257  *	call sdio_claim_host() nor sdio_release_host().
258  */
259 int sdio_claim_irq(struct sdio_func *func, sdio_irq_handler_t *handler)
260 {
261 	int ret;
262 	unsigned char reg;
263 
264 	BUG_ON(!func);
265 	BUG_ON(!func->card);
266 
267 	pr_debug("SDIO: Enabling IRQ for %s...\n", sdio_func_id(func));
268 
269 	if (func->irq_handler) {
270 		pr_debug("SDIO: IRQ for %s already in use.\n", sdio_func_id(func));
271 		return -EBUSY;
272 	}
273 
274 	ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, &reg);
275 	if (ret)
276 		return ret;
277 
278 	reg |= 1 << func->num;
279 
280 	reg |= 1; /* Master interrupt enable */
281 
282 	ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL);
283 	if (ret)
284 		return ret;
285 
286 	func->irq_handler = handler;
287 	ret = sdio_card_irq_get(func->card);
288 	if (ret)
289 		func->irq_handler = NULL;
290 	sdio_single_irq_set(func->card);
291 
292 	return ret;
293 }
294 EXPORT_SYMBOL_GPL(sdio_claim_irq);
295 
296 /**
297  *	sdio_release_irq - release the IRQ for a SDIO function
298  *	@func: SDIO function
299  *
300  *	Disable and release the IRQ for the given SDIO function.
301  */
302 int sdio_release_irq(struct sdio_func *func)
303 {
304 	int ret;
305 	unsigned char reg;
306 
307 	BUG_ON(!func);
308 	BUG_ON(!func->card);
309 
310 	pr_debug("SDIO: Disabling IRQ for %s...\n", sdio_func_id(func));
311 
312 	if (func->irq_handler) {
313 		func->irq_handler = NULL;
314 		sdio_card_irq_put(func->card);
315 		sdio_single_irq_set(func->card);
316 	}
317 
318 	ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, &reg);
319 	if (ret)
320 		return ret;
321 
322 	reg &= ~(1 << func->num);
323 
324 	/* Disable master interrupt with the last function interrupt */
325 	if (!(reg & 0xFE))
326 		reg = 0;
327 
328 	ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL);
329 	if (ret)
330 		return ret;
331 
332 	return 0;
333 }
334 EXPORT_SYMBOL_GPL(sdio_release_irq);
335 
336