drivers/mmc/core/sdio_irq.c - maze/linux - Git at Google

 /*
  * linux/drivers/mmc/core/sdio_irq.c
  *
  * Author:      Nicolas Pitre
  * Created:     June 18, 2007
  * Copyright:   MontaVista Software Inc.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or (at
  * your option) any later version.
  */

 #include <linux/kernel.h>
 #include <linux/sched.h>
 #include <linux/kthread.h>
 #include <linux/wait.h>
 #include <linux/delay.h>

 #include <linux/mmc/core.h>
 #include <linux/mmc/host.h>
 #include <linux/mmc/card.h>
 #include <linux/mmc/sdio.h>
 #include <linux/mmc/sdio_func.h>

 #include "sdio_ops.h"

 static int process_sdio_pending_irqs(struct mmc_card *card)
 {
 	int i, ret, count;
 	unsigned char pending;

 	ret = mmc_io_rw_direct(card, 0, 0, SDIO_CCCR_INTx, 0, &pending);
 	if (ret) {
 		printk(KERN_DEBUG "%s: error %d reading SDIO_CCCR_INTx\n",
 		       mmc_card_id(card), ret);
 		return ret;
 	}

 	count = 0;
 	for (i = 1; i <= 7; i++) {
 		if (pending & (1 << i)) {
 			struct sdio_func *func = card->sdio_func[i - 1];
 			if (!func) {
 				printk(KERN_WARNING "%s: pending IRQ for "
 					"non-existant function\n",
 					mmc_card_id(card));
 				ret = -EINVAL;
 			} else if (func->irq_handler) {
 				func->irq_handler(func);
 				count++;
 			} else {
 				printk(KERN_WARNING "%s: pending IRQ with no handler\n",
 				       sdio_func_id(func));
 				ret = -EINVAL;
 			}
 		}
 	}

 	if (count)
 		return count;

 	return ret;
 }

 static int sdio_irq_thread(void *_host)
 {
 	struct mmc_host *host = _host;
 	struct sched_param param = { .sched_priority = 1 };
 	unsigned long period, idle_period;
 	int ret;

 	sched_setscheduler(current, SCHED_FIFO, &param);

 	/*
 	 * We want to allow for SDIO cards to work even on non SDIO
 	 * aware hosts.  One thing that non SDIO host cannot do is
 	 * asynchronous notification of pending SDIO card interrupts
 	 * hence we poll for them in that case.
 	 */
 	idle_period = msecs_to_jiffies(10);
 	period = (host->caps & MMC_CAP_SDIO_IRQ) ?
 		MAX_SCHEDULE_TIMEOUT : idle_period;

 	pr_debug("%s: IRQ thread started (poll period = %lu jiffies)\n",
 		 mmc_hostname(host), period);

 	do {
 		/*
 		 * We claim the host here on drivers behalf for a couple
 		 * reasons:
 		 *
 		 * 1) it is already needed to retrieve the CCCR_INTx;
 		 * 2) we want the driver(s) to clear the IRQ condition ASAP;
 		 * 3) we need to control the abort condition locally.
 		 *
 		 * Just like traditional hard IRQ handlers, we expect SDIO
 		 * IRQ handlers to be quick and to the point, so that the
 		 * holding of the host lock does not cover too much work
 		 * that doesn't require that lock to be held.
 		 */
 		ret = __mmc_claim_host(host, &host->sdio_irq_thread_abort);
 		if (ret)
 			break;
 		ret = process_sdio_pending_irqs(host->card);
 		mmc_release_host(host);

 		/*
 		 * Give other threads a chance to run in the presence of
 		 * errors.  FIXME: determine if due to card removal and
 		 * possibly exit this thread if so.
 		 */
 		if (ret < 0)
 			ssleep(1);

 		/*
 		 * Adaptive polling frequency based on the assumption
 		 * that an interrupt will be closely followed by more.
 		 * This has a substantial benefit for network devices.
 		 */
 		if (!(host->caps & MMC_CAP_SDIO_IRQ)) {
 			if (ret > 0)
 				period /= 2;
 			else {
 				period++;
 				if (period > idle_period)
 					period = idle_period;
 			}
 		}

 		set_task_state(current, TASK_INTERRUPTIBLE);
 		if (host->caps & MMC_CAP_SDIO_IRQ)
 			host->ops->enable_sdio_irq(host, 1);
 		if (!kthread_should_stop())
 			schedule_timeout(period);
 		set_task_state(current, TASK_RUNNING);
 	} while (!kthread_should_stop());

 	if (host->caps & MMC_CAP_SDIO_IRQ)
 		host->ops->enable_sdio_irq(host, 0);

 	pr_debug("%s: IRQ thread exiting with code %d\n",
 		 mmc_hostname(host), ret);

 	return ret;
 }

 static int sdio_card_irq_get(struct mmc_card *card)
 {
 	struct mmc_host *host = card->host;

 	WARN_ON(!host->claimed);

 	if (!host->sdio_irqs++) {
 		atomic_set(&host->sdio_irq_thread_abort, 0);
 		host->sdio_irq_thread =
 			kthread_run(sdio_irq_thread, host, "ksdiorqd");
 		if (IS_ERR(host->sdio_irq_thread)) {
 			int err = PTR_ERR(host->sdio_irq_thread);
 			host->sdio_irqs--;
 			return err;
 		}
 	}

 	return 0;
 }

 static int sdio_card_irq_put(struct mmc_card *card)
 {
 	struct mmc_host *host = card->host;

 	WARN_ON(!host->claimed);
 	BUG_ON(host->sdio_irqs < 1);

 	if (!--host->sdio_irqs) {
 		atomic_set(&host->sdio_irq_thread_abort, 1);
 		kthread_stop(host->sdio_irq_thread);
 	}

 	return 0;
 }

 /**
  *	sdio_claim_irq - claim the IRQ for a SDIO function
  *	@func: SDIO function
  *	@handler: IRQ handler callback
  *
  *	Claim and activate the IRQ for the given SDIO function. The provided
  *	handler will be called when that IRQ is asserted.  The host is always
  *	claimed already when the handler is called so the handler must not
  *	call sdio_claim_host() nor sdio_release_host().
  */
 int sdio_claim_irq(struct sdio_func *func, sdio_irq_handler_t *handler)
 {
 	int ret;
 	unsigned char reg;

 	BUG_ON(!func);
 	BUG_ON(!func->card);

 	pr_debug("SDIO: Enabling IRQ for %s...\n", sdio_func_id(func));

 	if (func->irq_handler) {
 		pr_debug("SDIO: IRQ for %s already in use.\n", sdio_func_id(func));
 		return -EBUSY;
 	}

 	ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, &reg);
 	if (ret)
 		return ret;

 	reg |= 1 << func->num;

 	reg |= 1; /* Master interrupt enable */

 	ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL);
 	if (ret)
 		return ret;

 	func->irq_handler = handler;
 	ret = sdio_card_irq_get(func->card);
 	if (ret)
 		func->irq_handler = NULL;

 	return ret;
 }
 EXPORT_SYMBOL_GPL(sdio_claim_irq);

 /**
  *	sdio_release_irq - release the IRQ for a SDIO function
  *	@func: SDIO function
  *
  *	Disable and release the IRQ for the given SDIO function.
  */
 int sdio_release_irq(struct sdio_func *func)
 {
 	int ret;
 	unsigned char reg;

 	BUG_ON(!func);
 	BUG_ON(!func->card);

 	pr_debug("SDIO: Disabling IRQ for %s...\n", sdio_func_id(func));

 	if (func->irq_handler) {
 		func->irq_handler = NULL;
 		sdio_card_irq_put(func->card);
 	}

 	ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, &reg);
 	if (ret)
 		return ret;

 	reg &= ~(1 << func->num);

 	/* Disable master interrupt with the last function interrupt */
 	if (!(reg & 0xFE))
 		reg = 0;

 	ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL);
 	if (ret)
 		return ret;

 	return 0;
 }
 EXPORT_SYMBOL_GPL(sdio_release_irq);
	/*
	* linux/drivers/mmc/core/sdio_irq.c
	*
	* Author: Nicolas Pitre
	* Created: June 18, 2007
	* Copyright: MontaVista Software Inc.
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or (at
	* your option) any later version.
	*/

	#include <linux/kernel.h>
	#include <linux/sched.h>
	#include <linux/kthread.h>
	#include <linux/wait.h>
	#include <linux/delay.h>

	#include <linux/mmc/core.h>
	#include <linux/mmc/host.h>
	#include <linux/mmc/card.h>
	#include <linux/mmc/sdio.h>
	#include <linux/mmc/sdio_func.h>

	#include "sdio_ops.h"

	static int process_sdio_pending_irqs(struct mmc_card *card)
	{
	int i, ret, count;
	unsigned char pending;

	ret = mmc_io_rw_direct(card, 0, 0, SDIO_CCCR_INTx, 0, &pending);
	if (ret) {
	printk(KERN_DEBUG "%s: error %d reading SDIO_CCCR_INTx\n",
	mmc_card_id(card), ret);
	return ret;
	}

	count = 0;
	for (i = 1; i <= 7; i++) {
	if (pending & (1 << i)) {
	struct sdio_func *func = card->sdio_func[i - 1];
	if (!func) {
	printk(KERN_WARNING "%s: pending IRQ for "
	"non-existant function\n",
	mmc_card_id(card));
	ret = -EINVAL;
	} else if (func->irq_handler) {
	func->irq_handler(func);
	count++;
	} else {
	printk(KERN_WARNING "%s: pending IRQ with no handler\n",
	sdio_func_id(func));
	ret = -EINVAL;
	}
	}
	}

	if (count)
	return count;

	return ret;
	}

	static int sdio_irq_thread(void *_host)
	{
	struct mmc_host *host = _host;
	struct sched_param param = { .sched_priority = 1 };
	unsigned long period, idle_period;
	int ret;

	sched_setscheduler(current, SCHED_FIFO, &param);

	/*
	* We want to allow for SDIO cards to work even on non SDIO
	* aware hosts. One thing that non SDIO host cannot do is
	* asynchronous notification of pending SDIO card interrupts
	* hence we poll for them in that case.
	*/
	idle_period = msecs_to_jiffies(10);
	period = (host->caps & MMC_CAP_SDIO_IRQ) ?
	MAX_SCHEDULE_TIMEOUT : idle_period;

	pr_debug("%s: IRQ thread started (poll period = %lu jiffies)\n",
	mmc_hostname(host), period);

	do {
	/*
	* We claim the host here on drivers behalf for a couple
	* reasons:
	*
	* 1) it is already needed to retrieve the CCCR_INTx;
	* 2) we want the driver(s) to clear the IRQ condition ASAP;
	* 3) we need to control the abort condition locally.
	*
	* Just like traditional hard IRQ handlers, we expect SDIO
	* IRQ handlers to be quick and to the point, so that the
	* holding of the host lock does not cover too much work
	* that doesn't require that lock to be held.
	*/
	ret = __mmc_claim_host(host, &host->sdio_irq_thread_abort);
	if (ret)
	break;
	ret = process_sdio_pending_irqs(host->card);
	mmc_release_host(host);

	/*
	* Give other threads a chance to run in the presence of
	* errors. FIXME: determine if due to card removal and
	* possibly exit this thread if so.
	*/
	if (ret < 0)
	ssleep(1);

	/*
	* Adaptive polling frequency based on the assumption
	* that an interrupt will be closely followed by more.
	* This has a substantial benefit for network devices.
	*/
	if (!(host->caps & MMC_CAP_SDIO_IRQ)) {
	if (ret > 0)
	period /= 2;
	else {
	period++;
	if (period > idle_period)
	period = idle_period;
	}
	}

	set_task_state(current, TASK_INTERRUPTIBLE);
	if (host->caps & MMC_CAP_SDIO_IRQ)
	host->ops->enable_sdio_irq(host, 1);
	if (!kthread_should_stop())
	schedule_timeout(period);
	set_task_state(current, TASK_RUNNING);
	} while (!kthread_should_stop());

	if (host->caps & MMC_CAP_SDIO_IRQ)
	host->ops->enable_sdio_irq(host, 0);

	pr_debug("%s: IRQ thread exiting with code %d\n",
	mmc_hostname(host), ret);

	return ret;
	}

	static int sdio_card_irq_get(struct mmc_card *card)
	{
	struct mmc_host *host = card->host;

	WARN_ON(!host->claimed);

	if (!host->sdio_irqs++) {
	atomic_set(&host->sdio_irq_thread_abort, 0);
	host->sdio_irq_thread =
	kthread_run(sdio_irq_thread, host, "ksdiorqd");
	if (IS_ERR(host->sdio_irq_thread)) {
	int err = PTR_ERR(host->sdio_irq_thread);
	host->sdio_irqs--;
	return err;
	}
	}

	return 0;
	}

	static int sdio_card_irq_put(struct mmc_card *card)
	{
	struct mmc_host *host = card->host;

	WARN_ON(!host->claimed);
	BUG_ON(host->sdio_irqs < 1);

	if (!--host->sdio_irqs) {
	atomic_set(&host->sdio_irq_thread_abort, 1);
	kthread_stop(host->sdio_irq_thread);
	}

	return 0;
	}

	/**
	* sdio_claim_irq - claim the IRQ for a SDIO function
	* @func: SDIO function
	* @handler: IRQ handler callback
	*
	* Claim and activate the IRQ for the given SDIO function. The provided
	* handler will be called when that IRQ is asserted. The host is always
	* claimed already when the handler is called so the handler must not
	* call sdio_claim_host() nor sdio_release_host().
	*/
	int sdio_claim_irq(struct sdio_func func, sdio_irq_handler_t handler)
	{
	int ret;
	unsigned char reg;

	BUG_ON(!func);
	BUG_ON(!func->card);

	pr_debug("SDIO: Enabling IRQ for %s...\n", sdio_func_id(func));

	if (func->irq_handler) {
	pr_debug("SDIO: IRQ for %s already in use.\n", sdio_func_id(func));
	return -EBUSY;
	}

	ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, &reg);
	if (ret)
	return ret;

	reg \|= 1 << func->num;

	reg \|= 1; /* Master interrupt enable */

	ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL);
	if (ret)
	return ret;

	func->irq_handler = handler;
	ret = sdio_card_irq_get(func->card);
	if (ret)
	func->irq_handler = NULL;

	return ret;
	}
	EXPORT_SYMBOL_GPL(sdio_claim_irq);

	/**
	* sdio_release_irq - release the IRQ for a SDIO function
	* @func: SDIO function
	*
	* Disable and release the IRQ for the given SDIO function.
	*/
	int sdio_release_irq(struct sdio_func *func)
	{
	int ret;
	unsigned char reg;

	BUG_ON(!func);
	BUG_ON(!func->card);

	pr_debug("SDIO: Disabling IRQ for %s...\n", sdio_func_id(func));

	if (func->irq_handler) {
	func->irq_handler = NULL;
	sdio_card_irq_put(func->card);
	}

	ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, &reg);
	if (ret)
	return ret;

	reg &= ~(1 << func->num);

	/* Disable master interrupt with the last function interrupt */
	if (!(reg & 0xFE))
	reg = 0;

	ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL);
	if (ret)
	return ret;

	return 0;
	}
	EXPORT_SYMBOL_GPL(sdio_release_irq);