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Commit a62e8f19 authored by Alexey Starikovskiy's avatar Alexey Starikovskiy Committed by Len Brown
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ACPI: EC: Accelerate query execution 

Split EC query handling into acknowledge and execution phase.
This allows much smaller pending query lattency and lowers chances
of EC going "wild" and losing events.

Reference: http://bugzilla.kernel.org/show_bug.cgi?id=14858



Signed-off-by: default avatarAlexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parent fcb11235

drivers/acpi/ec.c

+77 −45
Original line number Diff line number Diff line
@@ -201,14 +201,13 @@ unlock: 
	spin_unlock_irqrestore(&ec->curr_lock, flags);

}



static void acpi_ec_gpe_query(void *ec_cxt);

static int acpi_ec_sync_query(struct acpi_ec *ec);



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

static int ec_check_sci_sync(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 acpi_ec_sync_query(ec);

	}

	return 0;

}
@@ -249,11 +248,6 @@ static int acpi_ec_transaction_unlocked(struct acpi_ec *ec, 
{

	unsigned long tmp;

	int ret = 0;

	pr_debug(PREFIX "transaction start\n");

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

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

		acpi_disable_gpe(NULL, ec->gpe);

	}

	if (EC_FLAGS_MSI)

		udelay(ACPI_EC_MSI_UDELAY);

	/* start transaction */
@@ -269,16 +263,6 @@ static int acpi_ec_transaction_unlocked(struct acpi_ec *ec, 
	spin_lock_irqsave(&ec->curr_lock, tmp);

	ec->curr = NULL;

	spin_unlock_irqrestore(&ec->curr_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);

	} else if (t->irq_count > ACPI_EC_STORM_THRESHOLD) {

		pr_info(PREFIX "GPE storm detected, "

			"transactions will use polling mode\n");

		set_bit(EC_FLAGS_GPE_STORM, &ec->flags);

	}

	return ret;

}
@@ -321,7 +305,24 @@ static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t) 
		status = -ETIME;

		goto end;

	}

	pr_debug(PREFIX "transaction start\n");

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

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

		acpi_disable_gpe(NULL, ec->gpe);

	}



	status = acpi_ec_transaction_unlocked(ec, t);



	/* check if we received SCI during transaction */

	ec_check_sci_sync(ec, acpi_ec_read_status(ec));

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

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

		acpi_enable_gpe(NULL, ec->gpe);

	} else if (t->irq_count > ACPI_EC_STORM_THRESHOLD) {

		pr_info(PREFIX "GPE storm detected, "

			"transactions will use polling mode\n");

		set_bit(EC_FLAGS_GPE_STORM, &ec->flags);

	}

end:

	if (ec->global_lock)

		acpi_release_global_lock(glk);
@@ -443,7 +444,7 @@ int ec_transaction(u8 command, 


EXPORT_SYMBOL(ec_transaction);



static int acpi_ec_query(struct acpi_ec *ec, u8 * data)

static int acpi_ec_query_unlocked(struct acpi_ec *ec, u8 * data)

{

	int result;

	u8 d;
@@ -452,20 +453,16 @@ static int acpi_ec_query(struct acpi_ec *ec, u8 * data) 
				.wlen = 0, .rlen = 1};

	if (!ec || !data)

		return -EINVAL;



	/*

	 * Query the EC to find out which _Qxx method we need to evaluate.

	 * Note that successful completion of the query causes the ACPI_EC_SCI

	 * bit to be cleared (and thus clearing the interrupt source).

	 */



	result = acpi_ec_transaction(ec, &t);

	result = acpi_ec_transaction_unlocked(ec, &t);

	if (result)

		return result;



	if (!d)

		return -ENODATA;



	*data = d;

	return 0;

}
@@ -509,43 +506,78 @@ void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit) 


EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);



static void acpi_ec_gpe_query(void *ec_cxt)

static void acpi_ec_run(void *cxt)

{

	struct acpi_ec *ec = ec_cxt;

	u8 value = 0;

	struct acpi_ec_query_handler *handler, copy;



	if (!ec || acpi_ec_query(ec, &value))

	struct acpi_ec_query_handler *handler = cxt;

	if (!handler)

		return;

	mutex_lock(&ec->lock);

	pr_debug(PREFIX "start query execution\n");

	if (handler->func)

		handler->func(handler->data);

	else if (handler->handle)

		acpi_evaluate_object(handler->handle, NULL, NULL, NULL);

	pr_debug(PREFIX "stop query execution\n");

	kfree(handler);

}



static int acpi_ec_sync_query(struct acpi_ec *ec)

{

	u8 value = 0;

	int status;

	struct acpi_ec_query_handler *handler, *copy;

	if ((status = acpi_ec_query_unlocked(ec, &value)))

		return status;

	list_for_each_entry(handler, &ec->list, node) {

		if (value == handler->query_bit) {

			/* have custom handler for this bit */

			memcpy(&copy, handler, sizeof(copy));

			mutex_unlock(&ec->lock);

			if (copy.func) {

				copy.func(copy.data);

			} else if (copy.handle) {

				acpi_evaluate_object(copy.handle, NULL, NULL, NULL);

			copy = kmalloc(sizeof(*handler), GFP_KERNEL);

			if (!copy)

				return -ENOMEM;

			memcpy(copy, handler, sizeof(*copy));

			pr_debug(PREFIX "push query execution (0x%2x) on queue\n", value);

			return acpi_os_execute(OSL_GPE_HANDLER,

				acpi_ec_run, copy);

		}

			return;

	}

	return 0;

}



static void acpi_ec_gpe_query(void *ec_cxt)

{

	struct acpi_ec *ec = ec_cxt;

	if (!ec)

		return;

	mutex_lock(&ec->lock);

	acpi_ec_sync_query(ec);

	mutex_unlock(&ec->lock);

}



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)) {

			pr_debug(PREFIX "push gpe query to the queue\n");

			return acpi_os_execute(OSL_NOTIFY_HANDLER,

				acpi_ec_gpe_query, ec);

		}

	}

	return 0;

}



static u32 acpi_ec_gpe_handler(void *data)

{

	struct acpi_ec *ec = data;

	u8 status;



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

	status = acpi_ec_read_status(ec);



	advance_transaction(ec, status);

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

	advance_transaction(ec, acpi_ec_read_status(ec));

	if (ec_transaction_done(ec) &&

	    (acpi_ec_read_status(ec) & ACPI_EC_FLAG_IBF) == 0) {

		wake_up(&ec->wait);

	ec_check_sci(ec, status);

		ec_check_sci(ec, acpi_ec_read_status(ec));

	}

	return ACPI_INTERRUPT_HANDLED;

}