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