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Commit 7c6db4e0 authored by Alexey Starikovskiy's avatar Alexey Starikovskiy Committed by Len Brown
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ACPI: EC: do transaction from interrupt context 

It is easier and faster to do transaction directly from interrupt context
rather than waking control thread.
Also, cleaner GPE storm avoidance is implemented.
References: 	http://bugzilla.kernel.org/show_bug.cgi?id=9998
		http://bugzilla.kernel.org/show_bug.cgi?id=10724
		http://bugzilla.kernel.org/show_bug.cgi?id=10919
		http://bugzilla.kernel.org/show_bug.cgi?id=11309
		http://bugzilla.kernel.org/show_bug.cgi?id=11549


Signed-off-by: default avatarAlexey Starikovskiy <astarikovskiy@suse.de>
Tested-by: default avatarSitsofe Wheeler <sitsofe@yahoo.com>
Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parent 72d31053

drivers/acpi/ec.c

+149 −160
Original line number Diff line number Diff line 
/*

 *  ec.c - ACPI Embedded Controller Driver (v2.0)

 *  ec.c - ACPI Embedded Controller Driver (v2.1)

 *

 *  Copyright (C) 2006, 2007 Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>

 *  Copyright (C) 2006-2008 Alexey Starikovskiy <astarikovskiy@suse.de>

 *  Copyright (C) 2006 Denis Sadykov <denis.m.sadykov@intel.com>

 *  Copyright (C) 2004 Luming Yu <luming.yu@intel.com>

 *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
@@ -26,7 +26,7 @@ 
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 */



/* Uncomment next line to get verbose print outs*/

/* Uncomment next line to get verbose printout */

/* #define DEBUG */



#include <linux/kernel.h>
@@ -38,6 +38,7 @@ 
#include <linux/seq_file.h>

#include <linux/interrupt.h>

#include <linux/list.h>

#include <linux/spinlock.h>

#include <asm/io.h>

#include <acpi/acpi_bus.h>

#include <acpi/acpi_drivers.h>
@@ -65,22 +66,21 @@ enum ec_command { 
	ACPI_EC_COMMAND_QUERY = 0x84,

};



/* EC events */

enum ec_event {

	ACPI_EC_EVENT_OBF_1 = 1,	/* Output buffer full */

	ACPI_EC_EVENT_IBF_0,		/* Input buffer empty */

};



#define ACPI_EC_DELAY		500	/* Wait 500ms max. during EC ops */

#define ACPI_EC_UDELAY_GLK	1000	/* Wait 1ms max. to get global lock */

#define ACPI_EC_UDELAY		100	/* Wait 100us before polling EC again */



#define ACPI_EC_STORM_THRESHOLD 20	/* number of false interrupts

					   per one transaction */



enum {

	EC_FLAGS_WAIT_GPE = 0,		/* Don't check status until GPE arrives */

	EC_FLAGS_QUERY_PENDING,		/* Query is pending */

	EC_FLAGS_GPE_MODE,		/* Expect GPE to be sent for status change */

	EC_FLAGS_GPE_MODE,		/* Expect GPE to be sent

					 * for status change */

	EC_FLAGS_NO_GPE,		/* Don't use GPE mode */

	EC_FLAGS_RESCHEDULE_POLL	/* Re-schedule poll */

	EC_FLAGS_GPE_STORM,		/* GPE storm detected */

	EC_FLAGS_HANDLERS_INSTALLED	/* Handlers for GPE and

					 * OpReg are installed */

};



/* If we find an EC via the ECDT, we need to keep a ptr to its context */
@@ -95,6 +95,14 @@ struct acpi_ec_query_handler { 
	u8 query_bit;

};



struct transaction_data {

	const u8 *wdata;

	u8 *rdata;

	unsigned short irq_count;

	u8 wlen;

	u8 rlen;

};



static struct acpi_ec {

	acpi_handle handle;

	unsigned long gpe;
@@ -105,9 +113,8 @@ static struct acpi_ec { 
	struct mutex lock;

	wait_queue_head_t wait;

	struct list_head list;

	struct delayed_work work;

	atomic_t irq_count;

	u8 handlers_installed;

	struct transaction_data *t;

	spinlock_t t_lock;

} *boot_ec, *first_ec;



/*
@@ -150,7 +157,7 @@ static inline u8 acpi_ec_read_data(struct acpi_ec *ec) 
{

	u8 x = inb(ec->data_addr);

	pr_debug(PREFIX "---> data = 0x%2.2x\n", x);

	return inb(ec->data_addr);

	return x;

}



static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
@@ -165,68 +172,79 @@ static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data) 
	outb(data, ec->data_addr);

}



static inline int acpi_ec_check_status(struct acpi_ec *ec, enum ec_event event)

static int ec_transaction_done(struct acpi_ec *ec)

{

	if (test_bit(EC_FLAGS_WAIT_GPE, &ec->flags))

		return 0;

	if (event == ACPI_EC_EVENT_OBF_1) {

		if (acpi_ec_read_status(ec) & ACPI_EC_FLAG_OBF)

			return 1;

	} else if (event == ACPI_EC_EVENT_IBF_0) {

		if (!(acpi_ec_read_status(ec) & ACPI_EC_FLAG_IBF))

			return 1;

	}



	return 0;

	unsigned long flags;

	int ret = 0;

	spin_lock_irqsave(&ec->t_lock, flags);

	if (!ec->t || (!ec->t->wlen && !ec->t->rlen))

		ret = 1;

	spin_unlock_irqrestore(&ec->t_lock, flags);

	return ret;

}



static void ec_schedule_ec_poll(struct acpi_ec *ec)

static void gpe_transaction(struct acpi_ec *ec, u8 status)

{

	if (test_bit(EC_FLAGS_RESCHEDULE_POLL, &ec->flags))

		schedule_delayed_work(&ec->work,

				      msecs_to_jiffies(ACPI_EC_DELAY));

}

	unsigned long flags;

	spin_lock_irqsave(&ec->t_lock, flags);

	if (!ec->t)

		goto unlock;

	if (ec->t->wlen > 0) {

		if ((status & ACPI_EC_FLAG_IBF) == 0) {

			acpi_ec_write_data(ec, *(ec->t->wdata++));

			--ec->t->wlen;

		} else

			/* false interrupt, state didn't change */

			++ec->t->irq_count;



static void ec_switch_to_poll_mode(struct acpi_ec *ec)

{

	set_bit(EC_FLAGS_NO_GPE, &ec->flags);

	clear_bit(EC_FLAGS_GPE_MODE, &ec->flags);

	acpi_disable_gpe(NULL, ec->gpe, ACPI_NOT_ISR);

	set_bit(EC_FLAGS_RESCHEDULE_POLL, &ec->flags);

	} else if (ec->t->rlen > 0) {

		if ((status & ACPI_EC_FLAG_OBF) == 1) {

			*(ec->t->rdata++) = acpi_ec_read_data(ec);

			--ec->t->rlen;

		} else

			/* false interrupt, state didn't change */

			++ec->t->irq_count;

	}

unlock:

	spin_unlock_irqrestore(&ec->t_lock, flags);

}



static int acpi_ec_wait(struct acpi_ec *ec, enum ec_event event, int force_poll)

static int acpi_ec_wait(struct acpi_ec *ec)

{

	atomic_set(&ec->irq_count, 0);

	if (likely(test_bit(EC_FLAGS_GPE_MODE, &ec->flags)) &&

	    likely(!force_poll)) {

		if (wait_event_timeout(ec->wait, acpi_ec_check_status(ec, event),

	if (wait_event_timeout(ec->wait, ec_transaction_done(ec),

			       msecs_to_jiffies(ACPI_EC_DELAY)))

		return 0;

		clear_bit(EC_FLAGS_WAIT_GPE, &ec->flags);

		if (acpi_ec_check_status(ec, event)) {

	/* missing GPEs, switch back to poll mode */

	if (printk_ratelimit())

		pr_info(PREFIX "missing confirmations, "

				"switch off interrupt mode.\n");

			ec_switch_to_poll_mode(ec);

			ec_schedule_ec_poll(ec);

	set_bit(EC_FLAGS_NO_GPE, &ec->flags);

	clear_bit(EC_FLAGS_GPE_MODE, &ec->flags);

	return 1;

}



static void acpi_ec_gpe_query(void *ec_cxt);



static int ec_check_sci(struct acpi_ec *ec, u8 state)

{

	if (state & ACPI_EC_FLAG_SCI) {

		if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags))

			return acpi_os_execute(OSL_EC_BURST_HANDLER,

				acpi_ec_gpe_query, ec);

	}

	return 0;

}

	} else {



static int ec_poll(struct acpi_ec *ec)

{

	unsigned long delay = jiffies + msecs_to_jiffies(ACPI_EC_DELAY);

		clear_bit(EC_FLAGS_WAIT_GPE, &ec->flags);

	msleep(1);

	while (time_before(jiffies, delay)) {

			if (acpi_ec_check_status(ec, event))

				return 0;

		gpe_transaction(ec, acpi_ec_read_status(ec));

		msleep(1);

		}

		if (acpi_ec_check_status(ec,event))

		if (ec_transaction_done(ec))

			return 0;

	}

	pr_err(PREFIX "acpi_ec_wait timeout, status = 0x%2.2x, event = %s\n",

		acpi_ec_read_status(ec),

		(event == ACPI_EC_EVENT_OBF_1) ? "\"b0=1\"" : "\"b1=0\"");

	return -ETIME;

}
@@ -235,45 +253,51 @@ static int acpi_ec_transaction_unlocked(struct acpi_ec *ec, u8 command, 
					u8 * rdata, unsigned rdata_len,

					int force_poll)

{

	int result = 0;

	set_bit(EC_FLAGS_WAIT_GPE, &ec->flags);

	unsigned long tmp;

	struct transaction_data t = {.wdata = wdata, .rdata = rdata,

				     .wlen = wdata_len, .rlen = rdata_len,

				     .irq_count = 0};

	int ret = 0;

	pr_debug(PREFIX "transaction start\n");

	acpi_ec_write_cmd(ec, command);

	for (; wdata_len > 0; --wdata_len) {

		result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0, force_poll);

		if (result) {

			pr_err(PREFIX

			       "write_cmd timeout, command = %d\n", command);

			goto end;

		}

		set_bit(EC_FLAGS_WAIT_GPE, &ec->flags);

		acpi_ec_write_data(ec, *(wdata++));

	}



	if (!rdata_len) {

		result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0, force_poll);

		if (result) {

			pr_err(PREFIX

			       "finish-write timeout, command = %d\n", command);

			goto end;

	/* disable GPE during transaction if storm is detected */

	if (test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) {

		clear_bit(EC_FLAGS_GPE_MODE, &ec->flags);

		acpi_disable_gpe(NULL, ec->gpe, ACPI_NOT_ISR);

	}

	} else if (command == ACPI_EC_COMMAND_QUERY)

	/* start transaction */

	spin_lock_irqsave(&ec->t_lock, tmp);

	/* following two actions should be kept atomic */

	ec->t = &t;

	acpi_ec_write_cmd(ec, command);

	if (command == ACPI_EC_COMMAND_QUERY)

		clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);



	for (; rdata_len > 0; --rdata_len) {

		result = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF_1, force_poll);

		if (result) {

			pr_err(PREFIX "read timeout, command = %d\n", command);

			goto end;

	spin_unlock_irqrestore(&ec->t_lock, tmp);

	/* if we selected poll mode or failed in GPE-mode do a poll loop */

	if (force_poll ||

	    !test_bit(EC_FLAGS_GPE_MODE, &ec->flags) ||

	    acpi_ec_wait(ec))

		ret = ec_poll(ec);

	pr_debug(PREFIX "transaction end\n");

	spin_lock_irqsave(&ec->t_lock, tmp);

	ec->t = NULL;

	spin_unlock_irqrestore(&ec->t_lock, tmp);

	if (test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) {

		/* check if we received SCI during transaction */

		ec_check_sci(ec, acpi_ec_read_status(ec));

		/* it is safe to enable GPE outside of transaction */

		acpi_enable_gpe(NULL, ec->gpe, ACPI_NOT_ISR);

	} else if (test_bit(EC_FLAGS_GPE_MODE, &ec->flags) &&

		   t.irq_count > ACPI_EC_STORM_THRESHOLD) {

		pr_debug(PREFIX "GPE storm detected\n");

		set_bit(EC_FLAGS_GPE_STORM, &ec->flags);

	}

		/* Don't expect GPE after last read */

		if (rdata_len > 1)

			set_bit(EC_FLAGS_WAIT_GPE, &ec->flags);

		*(rdata++) = acpi_ec_read_data(ec);

	return ret;

}

      end:

	pr_debug(PREFIX "transaction end\n");

	return result;



static int ec_check_ibf0(struct acpi_ec *ec)

{

	u8 status = acpi_ec_read_status(ec);

	return (status & ACPI_EC_FLAG_IBF) == 0;

}



static int acpi_ec_transaction(struct acpi_ec *ec, u8 command,
@@ -283,40 +307,34 @@ static int acpi_ec_transaction(struct acpi_ec *ec, u8 command, 
{

	int status;

	u32 glk;



	if (!ec || (wdata_len && !wdata) || (rdata_len && !rdata))

		return -EINVAL;



	if (rdata)

		memset(rdata, 0, rdata_len);



	mutex_lock(&ec->lock);

	if (ec->global_lock) {

		status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);

		if (ACPI_FAILURE(status)) {

			mutex_unlock(&ec->lock);

			return -ENODEV;

			status = -ENODEV;

			goto unlock;

		}

	}



	status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0, 0);

	if (status) {

	if (!wait_event_timeout(ec->wait, ec_check_ibf0(ec),

				msecs_to_jiffies(ACPI_EC_DELAY))) {

		pr_err(PREFIX "input buffer is not empty, "

				"aborting transaction\n");

		status = -ETIME;

		goto end;

	}



	status = acpi_ec_transaction_unlocked(ec, command,

					      wdata, wdata_len,

					      rdata, rdata_len,

					      force_poll);



end:



	if (ec->global_lock)

		acpi_release_global_lock(glk);

unlock:

	mutex_unlock(&ec->lock);



	return status;

}
@@ -332,7 +350,9 @@ int acpi_ec_burst_enable(struct acpi_ec *ec) 


int acpi_ec_burst_disable(struct acpi_ec *ec)

{

	return acpi_ec_transaction(ec, ACPI_EC_BURST_DISABLE, NULL, 0, NULL, 0, 0);

	return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?

		acpi_ec_transaction(ec, ACPI_EC_BURST_DISABLE,

			NULL, 0, NULL, 0, 0) : 0;

}



static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 * data)
@@ -513,46 +533,26 @@ static void acpi_ec_gpe_query(void *ec_cxt) 


static u32 acpi_ec_gpe_handler(void *data)

{

	acpi_status status = AE_OK;

	struct acpi_ec *ec = data;

	u8 state = acpi_ec_read_status(ec);

	u8 status;



	pr_debug(PREFIX "~~~> interrupt\n");

	atomic_inc(&ec->irq_count);

	if (atomic_read(&ec->irq_count) > 5) {

		pr_err(PREFIX "GPE storm detected, disabling EC GPE\n");

		ec_switch_to_poll_mode(ec);

		goto end;

	}

	clear_bit(EC_FLAGS_WAIT_GPE, &ec->flags);

	if (test_bit(EC_FLAGS_GPE_MODE, &ec->flags))

	status = acpi_ec_read_status(ec);



	gpe_transaction(ec, status);

	if (ec_transaction_done(ec) && (status & ACPI_EC_FLAG_IBF) == 0)

		wake_up(&ec->wait);



	if (state & ACPI_EC_FLAG_SCI) {

		if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags))

			status = acpi_os_execute(OSL_EC_BURST_HANDLER,

				acpi_ec_gpe_query, ec);

	} else if (!test_bit(EC_FLAGS_GPE_MODE, &ec->flags) &&

		   !test_bit(EC_FLAGS_NO_GPE, &ec->flags) &&

		   in_interrupt()) {

	ec_check_sci(ec, status);

	if (!test_bit(EC_FLAGS_GPE_MODE, &ec->flags) &&

	    !test_bit(EC_FLAGS_NO_GPE, &ec->flags)) {

		/* this is non-query, must be confirmation */

		if (printk_ratelimit())

			pr_info(PREFIX "non-query interrupt received,"

				" switching to interrupt mode\n");

		set_bit(EC_FLAGS_GPE_MODE, &ec->flags);

		clear_bit(EC_FLAGS_RESCHEDULE_POLL, &ec->flags);

	}

end:

	ec_schedule_ec_poll(ec);

	return ACPI_SUCCESS(status) ?

	    ACPI_INTERRUPT_HANDLED : ACPI_INTERRUPT_NOT_HANDLED;

	}



static void do_ec_poll(struct work_struct *work)

{

	struct acpi_ec *ec = container_of(work, struct acpi_ec, work.work);

	atomic_set(&ec->irq_count, 0);

	(void)acpi_ec_gpe_handler(ec);

	return ACPI_INTERRUPT_HANDLED;

}



/* --------------------------------------------------------------------------
@@ -696,8 +696,7 @@ static struct acpi_ec *make_acpi_ec(void) 
	mutex_init(&ec->lock);

	init_waitqueue_head(&ec->wait);

	INIT_LIST_HEAD(&ec->list);

	INIT_DELAYED_WORK_DEFERRABLE(&ec->work, do_ec_poll);

	atomic_set(&ec->irq_count, 0);

	spin_lock_init(&ec->t_lock);

	return ec;

}
@@ -736,22 +735,15 @@ ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval) 
	return AE_CTRL_TERMINATE;

}



static void ec_poll_stop(struct acpi_ec *ec)

{

	clear_bit(EC_FLAGS_RESCHEDULE_POLL, &ec->flags);

	cancel_delayed_work(&ec->work);

}



static void ec_remove_handlers(struct acpi_ec *ec)

{

	ec_poll_stop(ec);

	if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,

				ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))

		pr_err(PREFIX "failed to remove space handler\n");

	if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,

				&acpi_ec_gpe_handler)))

		pr_err(PREFIX "failed to remove gpe handler\n");

	ec->handlers_installed = 0;

	clear_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);

}



static int acpi_ec_add(struct acpi_device *device)
@@ -846,17 +838,15 @@ ec_parse_io_ports(struct acpi_resource *resource, void *context) 
static int ec_install_handlers(struct acpi_ec *ec)

{

	acpi_status status;

	if (ec->handlers_installed)

	if (test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags))

		return 0;

	status = acpi_install_gpe_handler(NULL, ec->gpe,

				  ACPI_GPE_EDGE_TRIGGERED,

				  &acpi_ec_gpe_handler, ec);

	if (ACPI_FAILURE(status))

		return -ENODEV;



	acpi_set_gpe_type(NULL, ec->gpe, ACPI_GPE_TYPE_RUNTIME);

	acpi_enable_gpe(NULL, ec->gpe, ACPI_NOT_ISR);



	status = acpi_install_address_space_handler(ec->handle,

						    ACPI_ADR_SPACE_EC,

						    &acpi_ec_space_handler,
@@ -866,7 +856,7 @@ static int ec_install_handlers(struct acpi_ec *ec) 
		return -ENODEV;

	}



	ec->handlers_installed = 1;

	set_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);

	return 0;

}
@@ -887,7 +877,6 @@ static int acpi_ec_start(struct acpi_device *device) 


	/* EC is fully operational, allow queries */

	clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);

	ec_schedule_ec_poll(ec);

	return ret;

}
@@ -906,7 +895,7 @@ static int acpi_ec_stop(struct acpi_device *device, int type) 


int __init acpi_boot_ec_enable(void)

{

	if (!boot_ec || boot_ec->handlers_installed)

	if (!boot_ec || test_bit(EC_FLAGS_HANDLERS_INSTALLED, &boot_ec->flags))

		return 0;

	if (!ec_install_handlers(boot_ec)) {

		first_ec = boot_ec;