[ACPI] Enable EC Burst Mode

Fixes several Embedded Controller issues, including
button failure and battery status AE_TIME failure.

http://bugzilla.kernel.org/show_bug.cgi?id=3851

Based on patch by: Andi Kleen <ak@suse.de>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Luming Yu <luming.yu@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/ec.c

@@ -31,6 +31,7 @@
 #include <linux/delay.h>
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
+#include <linux/interrupt.h>
 #include <asm/io.h>
 #include <acpi/acpi_bus.h>
 #include <acpi/acpi_drivers.h>
@@ -49,17 +50,19 @@ ACPI_MODULE_NAME		("acpi_ec")
 
 #define ACPI_EC_FLAG_OBF	0x01	/* Output buffer full */
 #define ACPI_EC_FLAG_IBF	0x02	/* Input buffer full */
+#define ACPI_EC_FLAG_BURST	0x10	/* burst mode */
 #define ACPI_EC_FLAG_SCI	0x20	/* EC-SCI occurred */
 
 #define ACPI_EC_EVENT_OBF	0x01	/* Output buffer full */
 #define ACPI_EC_EVENT_IBE	0x02	/* Input buffer empty */
 
-#define ACPI_EC_UDELAY		100	/* Poll @ 100us increments */
-#define ACPI_EC_UDELAY_COUNT	1000	/* Wait 10ms max. during EC ops */
+#define ACPI_EC_DELAY		50	/* Wait 50ms max. during EC ops */
 #define ACPI_EC_UDELAY_GLK	1000	/* Wait 1ms max. to get global lock */
 
 #define ACPI_EC_COMMAND_READ	0x80
 #define ACPI_EC_COMMAND_WRITE	0x81
+#define ACPI_EC_BURST_ENABLE	0x82
+#define ACPI_EC_BURST_DISABLE	0x83
 #define ACPI_EC_COMMAND_QUERY	0x84
 
 static int acpi_ec_add (struct acpi_device *device);
@@ -87,7 +90,11 @@ struct acpi_ec {
 	struct acpi_generic_address	command_addr;
 	struct acpi_generic_address	data_addr;
 	unsigned long			global_lock;
-	spinlock_t			lock;
+	unsigned int			expect_event;
+	atomic_t			leaving_burst; /* 0 : No, 1 : Yes, 2: abort*/
+	atomic_t			pending_gpe;
+	struct semaphore		sem;
+	wait_queue_head_t		wait;
 };
 
 /* If we find an EC via the ECDT, we need to keep a ptr to its context */
@@ -100,59 +107,138 @@ static struct acpi_device *first_ec;
                              Transaction Management
    -------------------------------------------------------------------------- */
 
-static int
-acpi_ec_wait (
-	struct acpi_ec		*ec,
-	u8			event)
+static inline u32 acpi_ec_read_status(struct acpi_ec *ec)
 {
-	u32			acpi_ec_status = 0;
-	u32			i = ACPI_EC_UDELAY_COUNT;
+	u32	status = 0;
 
-	if (!ec)
-		return -EINVAL;
+	acpi_hw_low_level_read(8, &status, &ec->status_addr);
+	return status;
+}
+
+static int acpi_ec_wait(struct acpi_ec *ec, unsigned int event)
+{
+	int	result = 0;
+
+	ACPI_FUNCTION_TRACE("acpi_ec_wait");
 
-	/* Poll the EC status register waiting for the event to occur. */
+	ec->expect_event = event;
+	smp_mb();
+
+	result = wait_event_interruptible_timeout(ec->wait,
+					!ec->expect_event,
+					msecs_to_jiffies(ACPI_EC_DELAY));
+	
+	ec->expect_event = 0;
+	smp_mb();
+
+	if (result < 0){
+		ACPI_DEBUG_PRINT((ACPI_DB_ERROR," result  = %d ", result));
+		return_VALUE(result);
+	}
+
+	/*
+	 * Verify that the event in question has actually happened by
+	 * querying EC status. Do the check even if operation timed-out
+	 * to make sure that we did not miss interrupt.
+	 */
 	switch (event) {
 	case ACPI_EC_EVENT_OBF:
-		do {
-			acpi_hw_low_level_read(8, &acpi_ec_status, &ec->status_addr);
-			if (acpi_ec_status & ACPI_EC_FLAG_OBF)
-				return 0;
-			udelay(ACPI_EC_UDELAY);
-		} while (--i>0);
+		if (acpi_ec_read_status(ec) & ACPI_EC_FLAG_OBF)
+			return_VALUE(0);
 		break;
+
 	case ACPI_EC_EVENT_IBE:
-		do {
-			acpi_hw_low_level_read(8, &acpi_ec_status, &ec->status_addr);
-			if (!(acpi_ec_status & ACPI_EC_FLAG_IBF))
-				return 0;
-			udelay(ACPI_EC_UDELAY);
-		} while (--i>0);
+		if (~acpi_ec_read_status(ec) & ACPI_EC_FLAG_IBF)
+			return_VALUE(0);
 		break;
-	default:
-		return -EINVAL;
 	}
 
-	return -ETIME;
+	return_VALUE(-ETIME);
 }
 
 
+
+static int
+acpi_ec_enter_burst_mode (
+	struct acpi_ec		*ec)
+{
+	u32			tmp = 0;
+	int			status = 0;
+
+	ACPI_FUNCTION_TRACE("acpi_ec_enter_burst_mode");
+
+	status = acpi_ec_read_status(ec);
+	if (status != -EINVAL &&
+		!(status & ACPI_EC_FLAG_BURST)){
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO,"entering burst mode \n"));
+		acpi_hw_low_level_write(8, ACPI_EC_BURST_ENABLE, &ec->command_addr);
+		status = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF);
+		if (status){
+			acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+			ACPI_DEBUG_PRINT((ACPI_DB_ERROR," status = %d\n", status));
+			return_VALUE(-EINVAL);
+		}
+		acpi_hw_low_level_read(8, &tmp, &ec->data_addr);
+		acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+		if(tmp != 0x90 ) {/* Burst ACK byte*/
+			ACPI_DEBUG_PRINT((ACPI_DB_ERROR,"Ack failed \n"));
+			return_VALUE(-EINVAL);
+		}
+	} else
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO,"already be in burst mode \n"));
+	atomic_set(&ec->leaving_burst , 0);
+	return_VALUE(0);
+}
+
+static int
+acpi_ec_leave_burst_mode (
+	struct acpi_ec		*ec)
+{
+	int			status =0;
+
+	ACPI_FUNCTION_TRACE("acpi_ec_leave_burst_mode");
+
+	atomic_set(&ec->leaving_burst , 1);
+	status = acpi_ec_read_status(ec);
+	if (status != -EINVAL &&
+		(status & ACPI_EC_FLAG_BURST)){
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO,"leaving burst mode\n"));
+		acpi_hw_low_level_write(8, ACPI_EC_BURST_DISABLE, &ec->command_addr);
+		status = acpi_ec_wait(ec, ACPI_EC_FLAG_IBF);
+		if (status){
+			acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+			ACPI_DEBUG_PRINT((ACPI_DB_ERROR,"------->wait fail\n"));
+			return_VALUE(-EINVAL);
+		}
+		acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+		status = acpi_ec_read_status(ec);
+		if (status != -EINVAL &&
+			(status & ACPI_EC_FLAG_BURST)) {
+			ACPI_DEBUG_PRINT((ACPI_DB_ERROR,"------->status fail\n"));
+			return_VALUE(-EINVAL);
+		}
+	}else
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO,"already be in Non-burst mode \n"));
+	ACPI_DEBUG_PRINT((ACPI_DB_INFO,"leaving burst mode\n"));
+
+	return_VALUE(0);
+}
+
 static int
 acpi_ec_read (
 	struct acpi_ec		*ec,
 	u8			address,
 	u32			*data)
 {
-	acpi_status		status = AE_OK;
-	int			result = 0;
-	unsigned long		flags = 0;
-	u32			glk = 0;
+	int			status = 0;
+	u32			glk;
 
 	ACPI_FUNCTION_TRACE("acpi_ec_read");
 
 	if (!ec || !data)
 		return_VALUE(-EINVAL);
 
+retry:
 	*data = 0;
 
 	if (ec->global_lock) {
@@ -160,32 +246,50 @@ acpi_ec_read (
 		if (ACPI_FAILURE(status))
 			return_VALUE(-ENODEV);
 	}
-	
-	spin_lock_irqsave(&ec->lock, flags);
+
+	WARN_ON(in_interrupt());
+	down(&ec->sem);
+
+	if(acpi_ec_enter_burst_mode(ec))
+		goto end;
 
 	acpi_hw_low_level_write(8, ACPI_EC_COMMAND_READ, &ec->command_addr);
-	result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
-	if (result)
+	status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
+	acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+	if (status) {
 		goto end;
+	}
 
 	acpi_hw_low_level_write(8, address, &ec->data_addr);
-	result = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF);
-	if (result)
+	status= acpi_ec_wait(ec, ACPI_EC_EVENT_OBF);
+	if (status){
+		acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
 		goto end;
-
+	}
 
 	acpi_hw_low_level_read(8, data, &ec->data_addr);
+	acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
 
 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Read [%02x] from address [%02x]\n",
 		*data, address));
-
+	
 end:
-	spin_unlock_irqrestore(&ec->lock, flags);
+	acpi_ec_leave_burst_mode(ec);
+	up(&ec->sem);
 
 	if (ec->global_lock)
 		acpi_release_global_lock(glk);
 
-	return_VALUE(result);
+	if(atomic_read(&ec->leaving_burst) == 2){
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO,"aborted, retry ...\n"));
+		while(!atomic_read(&ec->pending_gpe)){
+			msleep(1);	
+		}
+		acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+		goto retry;
+	}
+
+	return_VALUE(status);
 }
 
 
@@ -195,49 +299,80 @@ acpi_ec_write (
 	u8			address,
 	u8			data)
 {
-	int			result = 0;
-	acpi_status		status = AE_OK;
-	unsigned long		flags = 0;
-	u32			glk = 0;
+	int			status = 0;
+	u32			glk;
+	u32			tmp;
 
 	ACPI_FUNCTION_TRACE("acpi_ec_write");
 
 	if (!ec)
 		return_VALUE(-EINVAL);
-
+retry:
 	if (ec->global_lock) {
 		status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
 		if (ACPI_FAILURE(status))
 			return_VALUE(-ENODEV);
 	}
 
-	spin_lock_irqsave(&ec->lock, flags);
+	WARN_ON(in_interrupt());
+	down(&ec->sem);
+
+	if(acpi_ec_enter_burst_mode(ec))
+		goto end;
+
+	status = acpi_ec_read_status(ec);
+	if (status != -EINVAL &&
+		!(status & ACPI_EC_FLAG_BURST)){
+		acpi_hw_low_level_write(8, ACPI_EC_BURST_ENABLE, &ec->command_addr);
+		status = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF);
+		if (status)
+			goto end;
+		acpi_hw_low_level_read(8, &tmp, &ec->data_addr);
+		if(tmp != 0x90 ) /* Burst ACK byte*/
+			goto end;
+	}
+	/*Now we are in burst mode*/
 
 	acpi_hw_low_level_write(8, ACPI_EC_COMMAND_WRITE, &ec->command_addr);
-	result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
-	if (result)
+	status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
+	acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+	if (status){
 		goto end;
+	}
 
 	acpi_hw_low_level_write(8, address, &ec->data_addr);
-	result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
-	if (result)
+	status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
+	if (status){
+		acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
 		goto end;
+	}
 
 	acpi_hw_low_level_write(8, data, &ec->data_addr);
-	result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
-	if (result)
+	status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
+	acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+	if (status)
 		goto end;
 
 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Wrote [%02x] to address [%02x]\n",
 		data, address));
 
 end:
-	spin_unlock_irqrestore(&ec->lock, flags);
+	acpi_ec_leave_burst_mode(ec);
+	up(&ec->sem);
 
 	if (ec->global_lock)
 		acpi_release_global_lock(glk);
 
-	return_VALUE(result);
+	if(atomic_read(&ec->leaving_burst) == 2){
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO,"aborted, retry ...\n"));
+		while(!atomic_read(&ec->pending_gpe)){
+			msleep(1);	
+		}
+		acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+		goto retry;
+	}
+
+	return_VALUE(status);
 }
 
 /*
@@ -289,16 +424,14 @@ acpi_ec_query (
 	struct acpi_ec		*ec,
 	u32			*data)
 {
-	int			result = 0;
-	acpi_status		status = AE_OK;
-	unsigned long		flags = 0;
-	u32			glk = 0;
+	int			status = 0;
+	u32			glk;
 
 	ACPI_FUNCTION_TRACE("acpi_ec_query");
 
 	if (!ec || !data)
 		return_VALUE(-EINVAL);
-
+retry:
 	*data = 0;
 
 	if (ec->global_lock) {
@@ -307,29 +440,43 @@ acpi_ec_query (
 			return_VALUE(-ENODEV);
 	}
 
+	down(&ec->sem);
+	if(acpi_ec_enter_burst_mode(ec))
+		goto end;
 	/*
 	 * 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).
 	 */
-	spin_lock_irqsave(&ec->lock, flags);
-
 	acpi_hw_low_level_write(8, ACPI_EC_COMMAND_QUERY, &ec->command_addr);
-	result = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF);
-	if (result)
+	status = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF);
+	if (status){
+		acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
 		goto end;
-	
+	}
+
 	acpi_hw_low_level_read(8, data, &ec->data_addr);
+	acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
 	if (!*data)
-		result = -ENODATA;
+		status = -ENODATA;
 
 end:
-	spin_unlock_irqrestore(&ec->lock, flags);
+	acpi_ec_leave_burst_mode(ec);
+	up(&ec->sem);
 
 	if (ec->global_lock)
 		acpi_release_global_lock(glk);
 
-	return_VALUE(result);
+	if(atomic_read(&ec->leaving_burst) == 2){
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO,"aborted, retry ...\n"));
+		while(!atomic_read(&ec->pending_gpe)){
+			msleep(1);	
+		}
+		acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+		goto retry;
+	}
+
+	return_VALUE(status);
 }
 
 
@@ -347,42 +494,29 @@ acpi_ec_gpe_query (
 	void			*ec_cxt)
 {
 	struct acpi_ec		*ec = (struct acpi_ec *) ec_cxt;
-	u32			value = 0;
-	unsigned long		flags = 0;
+	u32			value;
+	int			result = -ENODATA;
 	static char		object_name[5] = {'_','Q','0','0','\0'};
 	const char		hex[] = {'0','1','2','3','4','5','6','7',
 				         '8','9','A','B','C','D','E','F'};
 
 	ACPI_FUNCTION_TRACE("acpi_ec_gpe_query");
 
-	if (!ec_cxt)
-		goto end;	
+	if (acpi_ec_read_status(ec) & ACPI_EC_FLAG_SCI)
+		result = acpi_ec_query(ec, &value);
 
-	spin_lock_irqsave(&ec->lock, flags);
-	acpi_hw_low_level_read(8, &value, &ec->command_addr);
-	spin_unlock_irqrestore(&ec->lock, flags);
-
-	/* TBD: Implement asynch events!
-	 * NOTE: All we care about are EC-SCI's.  Other EC events are
-	 * handled via polling (yuck!).  This is because some systems
-	 * treat EC-SCIs as level (versus EDGE!) triggered, preventing
-	 *  a purely interrupt-driven approach (grumble, grumble).
-	 */
-	if (!(value & ACPI_EC_FLAG_SCI))
+	if (result)
 		goto end;
 
-	if (acpi_ec_query(ec, &value))
-		goto end;
-	
 	object_name[2] = hex[((value >> 4) & 0x0F)];
 	object_name[3] = hex[(value & 0x0F)];
 
 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Evaluating %s\n", object_name));
 
 	acpi_evaluate_object(ec->handle, object_name, NULL, NULL);
-
-end:
-	acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+	atomic_dec(&ec->pending_gpe);
+end:	
+	return;
 }
 
 static u32
@@ -390,6 +524,7 @@ acpi_ec_gpe_handler (
 	void			*data)
 {
 	acpi_status		status = AE_OK;
+	u32			value;
 	struct acpi_ec		*ec = (struct acpi_ec *) data;
 
 	if (!ec)
@@ -397,13 +532,39 @@ acpi_ec_gpe_handler (
 
 	acpi_disable_gpe(NULL, ec->gpe_bit, ACPI_ISR);
 
-	status = acpi_os_queue_for_execution(OSD_PRIORITY_GPE,
-		acpi_ec_gpe_query, ec);
+	value = acpi_ec_read_status(ec);
 
-	if (status == AE_OK)
-		return ACPI_INTERRUPT_HANDLED;
-	else
-		return ACPI_INTERRUPT_NOT_HANDLED;
+	if((value & ACPI_EC_FLAG_IBF) &&
+		!(value & ACPI_EC_FLAG_BURST) &&
+			(atomic_read(&ec->leaving_burst) == 0)) { 
+	/*
+	 * the embedded controller disables 
+	 * burst mode for any reason other 
+	 * than the burst disable command
+	 * to process critical event.
+	 */
+		atomic_set(&ec->leaving_burst , 2); /* block current pending transaction
+					and retry */
+		wake_up(&ec->wait);
+	}else {
+		if ((ec->expect_event == ACPI_EC_EVENT_OBF &&
+				(value & ACPI_EC_FLAG_OBF)) ||
+	    			(ec->expect_event == ACPI_EC_EVENT_IBE &&
+				!(value & ACPI_EC_FLAG_IBF))) {
+			ec->expect_event = 0;
+			wake_up(&ec->wait);
+			
+		}
+	}
+
+	if (value & ACPI_EC_FLAG_SCI){
+		atomic_add(1, &ec->pending_gpe) ;
+		status = acpi_os_queue_for_execution(OSD_PRIORITY_GPE,
+						acpi_ec_gpe_query, ec);
+	} 
+
+	return status == AE_OK ?
+		ACPI_INTERRUPT_HANDLED : ACPI_INTERRUPT_NOT_HANDLED;
 }
 
 /* --------------------------------------------------------------------------
@@ -421,10 +582,8 @@ acpi_ec_space_setup (
 	 * The EC object is in the handler context and is needed
 	 * when calling the acpi_ec_space_handler.
 	 */
-	if(function == ACPI_REGION_DEACTIVATE) 
-		*return_context = NULL;
-	else 
-		*return_context = handler_context;
+	*return_context  = (function != ACPI_REGION_DEACTIVATE) ?
+						handler_context : NULL;
 
 	return AE_OK;
 }
@@ -555,7 +714,7 @@ static int
 acpi_ec_add_fs (
 	struct acpi_device	*device)
 {
-	struct proc_dir_entry	*entry = NULL;
+	struct proc_dir_entry	*entry;
 
 	ACPI_FUNCTION_TRACE("acpi_ec_add_fs");
 
@@ -606,9 +765,9 @@ static int
 acpi_ec_add (
 	struct acpi_device	*device)
 {
-	int			result = 0;
-	acpi_status		status = AE_OK;
-	struct acpi_ec		*ec = NULL;
+	int			result;
+	acpi_status		status;
+	struct acpi_ec		*ec;
 	unsigned long		uid;
 
 	ACPI_FUNCTION_TRACE("acpi_ec_add");
@@ -623,7 +782,10 @@ acpi_ec_add (
 
 	ec->handle = device->handle;
 	ec->uid = -1;
-	spin_lock_init(&ec->lock);
+ 	atomic_set(&ec->pending_gpe, 0);
+ 	atomic_set(&ec->leaving_burst , 1);
+ 	init_MUTEX(&ec->sem);
+ 	init_waitqueue_head(&ec->wait);
 	strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
 	strcpy(acpi_device_class(device), ACPI_EC_CLASS);
 	acpi_driver_data(device) = ec;
@@ -637,7 +799,7 @@ acpi_ec_add (
 	if (ec_ecdt && ec_ecdt->uid == uid) {
 		acpi_remove_address_space_handler(ACPI_ROOT_OBJECT,
 			ACPI_ADR_SPACE_EC, &acpi_ec_space_handler);
-	
+
 		acpi_remove_gpe_handler(NULL, ec_ecdt->gpe_bit, &acpi_ec_gpe_handler);
 
 		kfree(ec_ecdt);
@@ -677,7 +839,7 @@ acpi_ec_remove (
 	struct acpi_device	*device,
 	int			type)
 {
-	struct acpi_ec		*ec = NULL;
+	struct acpi_ec		*ec;
 
 	ACPI_FUNCTION_TRACE("acpi_ec_remove");
 
@@ -732,8 +894,8 @@ static int
 acpi_ec_start (
 	struct acpi_device	*device)
 {
-	acpi_status		status = AE_OK;
-	struct acpi_ec		*ec = NULL;
+	acpi_status		status;
+	struct acpi_ec		*ec;
 
 	ACPI_FUNCTION_TRACE("acpi_ec_start");
 
@@ -789,8 +951,8 @@ acpi_ec_stop (
 	struct acpi_device	*device,
 	int			type)
 {
-	acpi_status		status = AE_OK;
-	struct acpi_ec		*ec = NULL;
+	acpi_status		status;
+	struct acpi_ec		*ec;
 
 	ACPI_FUNCTION_TRACE("acpi_ec_stop");
 
@@ -832,7 +994,6 @@ acpi_fake_ecdt_callback (
 	status = acpi_evaluate_integer(handle, "_GPE", NULL, &ec_ecdt->gpe_bit);
 	if (ACPI_FAILURE(status))
 		return status;
-	spin_lock_init(&ec_ecdt->lock);
 	ec_ecdt->global_lock = TRUE;
 	ec_ecdt->handle = handle;
 
@@ -890,7 +1051,7 @@ acpi_ec_get_real_ecdt(void)
 	acpi_status		status;
 	struct acpi_table_ecdt 	*ecdt_ptr;
 
-	status = acpi_get_firmware_table("ECDT", 1, ACPI_LOGICAL_ADDRESSING, 
+	status = acpi_get_firmware_table("ECDT", 1, ACPI_LOGICAL_ADDRESSING,
 		(struct acpi_table_header **) &ecdt_ptr);
 	if (ACPI_FAILURE(status))
 		return -ENODEV;
@@ -905,11 +1066,12 @@ acpi_ec_get_real_ecdt(void)
 		return -ENOMEM;
 	memset(ec_ecdt, 0, sizeof(struct acpi_ec));
 
+ 	init_MUTEX(&ec_ecdt->sem);
+ 	init_waitqueue_head(&ec_ecdt->wait);
 	ec_ecdt->command_addr = ecdt_ptr->ec_control;
 	ec_ecdt->status_addr = ecdt_ptr->ec_control;
 	ec_ecdt->data_addr = ecdt_ptr->ec_data;
 	ec_ecdt->gpe_bit = ecdt_ptr->gpe_bit;
-	spin_lock_init(&ec_ecdt->lock);
 	/* use the GL just to be safe */
 	ec_ecdt->global_lock = TRUE;
 	ec_ecdt->uid = ecdt_ptr->uid;
@@ -978,7 +1140,7 @@ error:
 
 static int __init acpi_ec_init (void)
 {
-	int			result = 0;
+	int			result;
 
 	ACPI_FUNCTION_TRACE("acpi_ec_init");