xref: /openbmc/linux/drivers/mmc/core/sdio_irq.c (revision 4e1a33b1) 
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 #include "core.h"
31 #include "card.h"
32 
33 static int process_sdio_pending_irqs(struct mmc_host *host)
34 {
35 	struct mmc_card *card = host->card;
36 	int i, ret, count;
37 	unsigned char pending;
38 	struct sdio_func *func;
39 
40 	/*
41 	 * Optimization, if there is only 1 function interrupt registered
42 	 * and we know an IRQ was signaled then call irq handler directly.
43 	 * Otherwise do the full probe.
44 	 */
45 	func = card->sdio_single_irq;
46 	if (func && host->sdio_irq_pending) {
47 		func->irq_handler(func);
48 		return 1;
49 	}
50 
51 	ret = mmc_io_rw_direct(card, 0, 0, SDIO_CCCR_INTx, 0, &pending);
52 	if (ret) {
53 		pr_debug("%s: error %d reading SDIO_CCCR_INTx\n",
54 		       mmc_card_id(card), ret);
55 		return ret;
56 	}
57 
58 	if (pending && mmc_card_broken_irq_polling(card) &&
59 	    !(host->caps & MMC_CAP_SDIO_IRQ)) {
60 		unsigned char dummy;
61 
62 		/* A fake interrupt could be created when we poll SDIO_CCCR_INTx
63 		 * register with a Marvell SD8797 card. A dummy CMD52 read to
64 		 * function 0 register 0xff can avoid this.
65 		 */
66 		mmc_io_rw_direct(card, 0, 0, 0xff, 0, &dummy);
67 	}
68 
69 	count = 0;
70 	for (i = 1; i <= 7; i++) {
71 		if (pending & (1 << i)) {
72 			func = card->sdio_func[i - 1];
73 			if (!func) {
74 				pr_warn("%s: pending IRQ for non-existent function\n",
75 					mmc_card_id(card));
76 				ret = -EINVAL;
77 			} else if (func->irq_handler) {
78 				func->irq_handler(func);
79 				count++;
80 			} else {
81 				pr_warn("%s: pending IRQ with no handler\n",
82 					sdio_func_id(func));
83 				ret = -EINVAL;
84 			}
85 		}
86 	}
87 
88 	if (count)
89 		return count;
90 
91 	return ret;
92 }
93 
94 void sdio_run_irqs(struct mmc_host *host)
95 {
96 	mmc_claim_host(host);
97 	host->sdio_irq_pending = true;
98 	process_sdio_pending_irqs(host);
99 	mmc_release_host(host);
100 }
101 EXPORT_SYMBOL_GPL(sdio_run_irqs);
102 
103 static int sdio_irq_thread(void *_host)
104 {
105 	struct mmc_host *host = _host;
106 	struct sched_param param = { .sched_priority = 1 };
107 	unsigned long period, idle_period;
108 	int ret;
109 
110 	sched_setscheduler(current, SCHED_FIFO, &param);
111 
112 	/*
113 	 * We want to allow for SDIO cards to work even on non SDIO
114 	 * aware hosts.  One thing that non SDIO host cannot do is
115 	 * asynchronous notification of pending SDIO card interrupts
116 	 * hence we poll for them in that case.
117 	 */
118 	idle_period = msecs_to_jiffies(10);
119 	period = (host->caps & MMC_CAP_SDIO_IRQ) ?
120 		MAX_SCHEDULE_TIMEOUT : idle_period;
121 
122 	pr_debug("%s: IRQ thread started (poll period = %lu jiffies)\n",
123 		 mmc_hostname(host), period);
124 
125 	do {
126 		/*
127 		 * We claim the host here on drivers behalf for a couple
128 		 * reasons:
129 		 *
130 		 * 1) it is already needed to retrieve the CCCR_INTx;
131 		 * 2) we want the driver(s) to clear the IRQ condition ASAP;
132 		 * 3) we need to control the abort condition locally.
133 		 *
134 		 * Just like traditional hard IRQ handlers, we expect SDIO
135 		 * IRQ handlers to be quick and to the point, so that the
136 		 * holding of the host lock does not cover too much work
137 		 * that doesn't require that lock to be held.
138 		 */
139 		ret = __mmc_claim_host(host, &host->sdio_irq_thread_abort);
140 		if (ret)
141 			break;
142 		ret = process_sdio_pending_irqs(host);
143 		host->sdio_irq_pending = false;
144 		mmc_release_host(host);
145 
146 		/*
147 		 * Give other threads a chance to run in the presence of
148 		 * errors.
149 		 */
150 		if (ret < 0) {
151 			set_current_state(TASK_INTERRUPTIBLE);
152 			if (!kthread_should_stop())
153 				schedule_timeout(HZ);
154 			set_current_state(TASK_RUNNING);
155 		}
156 
157 		/*
158 		 * Adaptive polling frequency based on the assumption
159 		 * that an interrupt will be closely followed by more.
160 		 * This has a substantial benefit for network devices.
161 		 */
162 		if (!(host->caps & MMC_CAP_SDIO_IRQ)) {
163 			if (ret > 0)
164 				period /= 2;
165 			else {
166 				period++;
167 				if (period > idle_period)
168 					period = idle_period;
169 			}
170 		}
171 
172 		set_current_state(TASK_INTERRUPTIBLE);
173 		if (host->caps & MMC_CAP_SDIO_IRQ)
174 			host->ops->enable_sdio_irq(host, 1);
175 		if (!kthread_should_stop())
176 			schedule_timeout(period);
177 		set_current_state(TASK_RUNNING);
178 	} while (!kthread_should_stop());
179 
180 	if (host->caps & MMC_CAP_SDIO_IRQ)
181 		host->ops->enable_sdio_irq(host, 0);
182 
183 	pr_debug("%s: IRQ thread exiting with code %d\n",
184 		 mmc_hostname(host), ret);
185 
186 	return ret;
187 }
188 
189 static int sdio_card_irq_get(struct mmc_card *card)
190 {
191 	struct mmc_host *host = card->host;
192 
193 	WARN_ON(!host->claimed);
194 
195 	if (!host->sdio_irqs++) {
196 		if (!(host->caps2 & MMC_CAP2_SDIO_IRQ_NOTHREAD)) {
197 			atomic_set(&host->sdio_irq_thread_abort, 0);
198 			host->sdio_irq_thread =
199 				kthread_run(sdio_irq_thread, host,
200 					    "ksdioirqd/%s", mmc_hostname(host));
201 			if (IS_ERR(host->sdio_irq_thread)) {
202 				int err = PTR_ERR(host->sdio_irq_thread);
203 				host->sdio_irqs--;
204 				return err;
205 			}
206 		} else if (host->caps & MMC_CAP_SDIO_IRQ) {
207 			host->ops->enable_sdio_irq(host, 1);
208 		}
209 	}
210 
211 	return 0;
212 }
213 
214 static int sdio_card_irq_put(struct mmc_card *card)
215 {
216 	struct mmc_host *host = card->host;
217 
218 	WARN_ON(!host->claimed);
219 
220 	if (host->sdio_irqs < 1)
221 		return -EINVAL;
222 
223 	if (!--host->sdio_irqs) {
224 		if (!(host->caps2 & MMC_CAP2_SDIO_IRQ_NOTHREAD)) {
225 			atomic_set(&host->sdio_irq_thread_abort, 1);
226 			kthread_stop(host->sdio_irq_thread);
227 		} else if (host->caps & MMC_CAP_SDIO_IRQ) {
228 			host->ops->enable_sdio_irq(host, 0);
229 		}
230 	}
231 
232 	return 0;
233 }
234 
235 /* If there is only 1 function registered set sdio_single_irq */
236 static void sdio_single_irq_set(struct mmc_card *card)
237 {
238 	struct sdio_func *func;
239 	int i;
240 
241 	card->sdio_single_irq = NULL;
242 	if ((card->host->caps & MMC_CAP_SDIO_IRQ) &&
243 	    card->host->sdio_irqs == 1)
244 		for (i = 0; i < card->sdio_funcs; i++) {
245 		       func = card->sdio_func[i];
246 		       if (func && func->irq_handler) {
247 			       card->sdio_single_irq = func;
248 			       break;
249 		       }
250 	       }
251 }
252 
253 /**
254  *	sdio_claim_irq - claim the IRQ for a SDIO function
255  *	@func: SDIO function
256  *	@handler: IRQ handler callback
257  *
258  *	Claim and activate the IRQ for the given SDIO function. The provided
259  *	handler will be called when that IRQ is asserted.  The host is always
260  *	claimed already when the handler is called so the handler must not
261  *	call sdio_claim_host() nor sdio_release_host().
262  */
263 int sdio_claim_irq(struct sdio_func *func, sdio_irq_handler_t *handler)
264 {
265 	int ret;
266 	unsigned char reg;
267 
268 	if (!func)
269 		return -EINVAL;
270 
271 	pr_debug("SDIO: Enabling IRQ for %s...\n", sdio_func_id(func));
272 
273 	if (func->irq_handler) {
274 		pr_debug("SDIO: IRQ for %s already in use.\n", sdio_func_id(func));
275 		return -EBUSY;
276 	}
277 
278 	ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, &reg);
279 	if (ret)
280 		return ret;
281 
282 	reg |= 1 << func->num;
283 
284 	reg |= 1; /* Master interrupt enable */
285 
286 	ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL);
287 	if (ret)
288 		return ret;
289 
290 	func->irq_handler = handler;
291 	ret = sdio_card_irq_get(func->card);
292 	if (ret)
293 		func->irq_handler = NULL;
294 	sdio_single_irq_set(func->card);
295 
296 	return ret;
297 }
298 EXPORT_SYMBOL_GPL(sdio_claim_irq);
299 
300 /**
301  *	sdio_release_irq - release the IRQ for a SDIO function
302  *	@func: SDIO function
303  *
304  *	Disable and release the IRQ for the given SDIO function.
305  */
306 int sdio_release_irq(struct sdio_func *func)
307 {
308 	int ret;
309 	unsigned char reg;
310 
311 	if (!func)
312 		return -EINVAL;
313 
314 	pr_debug("SDIO: Disabling IRQ for %s...\n", sdio_func_id(func));
315 
316 	if (func->irq_handler) {
317 		func->irq_handler = NULL;
318 		sdio_card_irq_put(func->card);
319 		sdio_single_irq_set(func->card);
320 	}
321 
322 	ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, &reg);
323 	if (ret)
324 		return ret;
325 
326 	reg &= ~(1 << func->num);
327 
328 	/* Disable master interrupt with the last function interrupt */
329 	if (!(reg & 0xFE))
330 		reg = 0;
331 
332 	ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL);
333 	if (ret)
334 		return ret;
335 
336 	return 0;
337 }
338 EXPORT_SYMBOL_GPL(sdio_release_irq);
339 
340