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/wait.h>
20 #include <linux/delay.h>
21
22 #include <linux/mmc/core.h>
23 #include <linux/mmc/host.h>
24 #include <linux/mmc/card.h>
25 #include <linux/mmc/sdio.h>
26 #include <linux/mmc/sdio_func.h>
27
28 #include "sdio_ops.h"
29
process_sdio_pending_irqs(struct mmc_card * card)30 static int process_sdio_pending_irqs(struct mmc_card *card)
31 {
32 int i, ret, count;
33 unsigned char pending;
34
35 ret = mmc_io_rw_direct(card, 0, 0, SDIO_CCCR_INTx, 0, &pending);
36 if (ret) {
37 printk(KERN_DEBUG "%s: error %d reading SDIO_CCCR_INTx\n",
38 mmc_card_id(card), ret);
39 return ret;
40 }
41
42 count = 0;
43 for (i = 1; i <= 7; i++) {
44 if (pending & (1 << i)) {
45 struct sdio_func *func = card->sdio_func[i - 1];
46 if (!func) {
47 printk(KERN_WARNING "%s: pending IRQ for "
48 "non-existent function\n",
49 mmc_card_id(card));
50 ret = -EINVAL;
51 } else if (func->irq_handler) {
52 func->irq_handler(func);
53 count++;
54 } else {
55 printk(KERN_WARNING "%s: pending IRQ with no handler\n",
56 sdio_func_id(func));
57 ret = -EINVAL;
58 }
59 }
60 }
61
62 if (count)
63 return count;
64
65 return ret;
66 }
67
sdio_irq_thread(void * _host)68 static int sdio_irq_thread(void *_host)
69 {
70 struct mmc_host *host = _host;
71 struct sched_param param = { .sched_priority = 1 };
72 unsigned long period, idle_period;
73 int ret;
74
75 sched_setscheduler(current, SCHED_FIFO, ¶m);
76
77 /*
78 * We want to allow for SDIO cards to work even on non SDIO
79 * aware hosts. One thing that non SDIO host cannot do is
80 * asynchronous notification of pending SDIO card interrupts
81 * hence we poll for them in that case.
82 */
83 idle_period = msecs_to_jiffies(10);
84 period = (host->caps & MMC_CAP_SDIO_IRQ) ?
85 MAX_SCHEDULE_TIMEOUT : idle_period;
86
87 pr_debug("%s: IRQ thread started (poll period = %lu jiffies)\n",
88 mmc_hostname(host), period);
89
90 do {
91 /*
92 * We claim the host here on drivers behalf for a couple
93 * reasons:
94 *
95 * 1) it is already needed to retrieve the CCCR_INTx;
96 * 2) we want the driver(s) to clear the IRQ condition ASAP;
97 * 3) we need to control the abort condition locally.
98 *
99 * Just like traditional hard IRQ handlers, we expect SDIO
100 * IRQ handlers to be quick and to the point, so that the
101 * holding of the host lock does not cover too much work
102 * that doesn't require that lock to be held.
103 */
104 ret = __mmc_claim_host(host, &host->sdio_irq_thread_abort);
105 if (ret)
106 break;
107 ret = process_sdio_pending_irqs(host->card);
108 mmc_release_host(host);
109
110 /*
111 * Give other threads a chance to run in the presence of
112 * errors.
113 */
114 if (ret < 0) {
115 set_current_state(TASK_INTERRUPTIBLE);
116 if (!kthread_should_stop())
117 schedule_timeout(HZ);
118 set_current_state(TASK_RUNNING);
119 }
120
121 /*
122 * Adaptive polling frequency based on the assumption
123 * that an interrupt will be closely followed by more.
124 * This has a substantial benefit for network devices.
125 */
126 if (!(host->caps & MMC_CAP_SDIO_IRQ)) {
127 if (ret > 0)
128 period /= 2;
129 else {
130 period++;
131 if (period > idle_period)
132 period = idle_period;
133 }
134 }
135
136 set_current_state(TASK_INTERRUPTIBLE);
137 if (host->caps & MMC_CAP_SDIO_IRQ)
138 host->ops->enable_sdio_irq(host, 1);
139 if (!kthread_should_stop())
140 schedule_timeout(period);
141 set_current_state(TASK_RUNNING);
142 } while (!kthread_should_stop());
143
144 if (host->caps & MMC_CAP_SDIO_IRQ)
145 host->ops->enable_sdio_irq(host, 0);
146
147 pr_debug("%s: IRQ thread exiting with code %d\n",
148 mmc_hostname(host), ret);
149
150 return ret;
151 }
152
sdio_card_irq_get(struct mmc_card * card)153 static int sdio_card_irq_get(struct mmc_card *card)
154 {
155 struct mmc_host *host = card->host;
156
157 WARN_ON(!host->claimed);
158
159 if (!host->sdio_irqs++) {
160 atomic_set(&host->sdio_irq_thread_abort, 0);
161 host->sdio_irq_thread =
162 kthread_run(sdio_irq_thread, host, "ksdioirqd/%s",
163 mmc_hostname(host));
164 if (IS_ERR(host->sdio_irq_thread)) {
165 int err = PTR_ERR(host->sdio_irq_thread);
166 host->sdio_irqs--;
167 return err;
168 }
169 }
170
171 return 0;
172 }
173
sdio_card_irq_put(struct mmc_card * card)174 static int sdio_card_irq_put(struct mmc_card *card)
175 {
176 struct mmc_host *host = card->host;
177
178 WARN_ON(!host->claimed);
179 BUG_ON(host->sdio_irqs < 1);
180
181 if (!--host->sdio_irqs) {
182 atomic_set(&host->sdio_irq_thread_abort, 1);
183 kthread_stop(host->sdio_irq_thread);
184 }
185
186 return 0;
187 }
188
189 /**
190 * sdio_claim_irq - claim the IRQ for a SDIO function
191 * @func: SDIO function
192 * @handler: IRQ handler callback
193 *
194 * Claim and activate the IRQ for the given SDIO function. The provided
195 * handler will be called when that IRQ is asserted. The host is always
196 * claimed already when the handler is called so the handler must not
197 * call sdio_claim_host() nor sdio_release_host().
198 */
sdio_claim_irq(struct sdio_func * func,sdio_irq_handler_t * handler)199 int sdio_claim_irq(struct sdio_func *func, sdio_irq_handler_t *handler)
200 {
201 int ret;
202 unsigned char reg;
203
204 BUG_ON(!func);
205 BUG_ON(!func->card);
206
207 pr_debug("SDIO: Enabling IRQ for %s...\n", sdio_func_id(func));
208
209 if (func->irq_handler) {
210 pr_debug("SDIO: IRQ for %s already in use.\n", sdio_func_id(func));
211 return -EBUSY;
212 }
213
214 ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, ®);
215 if (ret)
216 return ret;
217
218 reg |= 1 << func->num;
219
220 reg |= 1; /* Master interrupt enable */
221
222 ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL);
223 if (ret)
224 return ret;
225
226 func->irq_handler = handler;
227 ret = sdio_card_irq_get(func->card);
228 if (ret)
229 func->irq_handler = NULL;
230
231 return ret;
232 }
233 EXPORT_SYMBOL_GPL(sdio_claim_irq);
234
235 /**
236 * sdio_release_irq - release the IRQ for a SDIO function
237 * @func: SDIO function
238 *
239 * Disable and release the IRQ for the given SDIO function.
240 */
sdio_release_irq(struct sdio_func * func)241 int sdio_release_irq(struct sdio_func *func)
242 {
243 int ret;
244 unsigned char reg;
245
246 BUG_ON(!func);
247 BUG_ON(!func->card);
248
249 pr_debug("SDIO: Disabling IRQ for %s...\n", sdio_func_id(func));
250
251 if (func->irq_handler) {
252 func->irq_handler = NULL;
253 sdio_card_irq_put(func->card);
254 }
255
256 ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, ®);
257 if (ret)
258 return ret;
259
260 reg &= ~(1 << func->num);
261
262 /* Disable master interrupt with the last function interrupt */
263 if (!(reg & 0xFE))
264 reg = 0;
265
266 ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL);
267 if (ret)
268 return ret;
269
270 return 0;
271 }
272 EXPORT_SYMBOL_GPL(sdio_release_irq);
273
274