ACPI: EC: add support for hardware-reduced systems

index c33756ed3304..37bbec89be82 100644
@@ -99,7 +99,7 @@ enum {
 	EC_FLAGS_EVT_HANDLER_INSTALLED, /* _Qxx handlers installed */
 	EC_FLAGS_STARTED,		/* Driver is started */
 	EC_FLAGS_STOPPED,		/* Driver is stopped */
-	EC_FLAGS_GPE_MASKED,		/* GPE masked */
+	EC_FLAGS_EVENTS_MASKED,		/* GPE or IRQ masked */
 };
 
 #define ACPI_EC_COMMAND_POLL		0x01 /* Available for command byte */

@@ -414,20 +414,26 @@ static void acpi_ec_complete_request(struct acpi_ec *ec)
 		wake_up(&ec->wait);
 }
 
-static void acpi_ec_mask_gpe(struct acpi_ec *ec)
+static void acpi_ec_mask_events(struct acpi_ec *ec)
 {
-	if (!test_bit(EC_FLAGS_GPE_MASKED, &ec->flags)) {
-		acpi_ec_disable_gpe(ec, false);
+	if (!test_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags)) {
+		if (ec->irq >= 0)
+			disable_irq_nosync(ec->irq);
+		else
+			acpi_ec_disable_gpe(ec, false);
 		ec_dbg_drv("Polling enabled");
-		set_bit(EC_FLAGS_GPE_MASKED, &ec->flags);
+		set_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags);
 	}
 }
 
-static void acpi_ec_unmask_gpe(struct acpi_ec *ec)
+static void acpi_ec_unmask_events(struct acpi_ec *ec)
 {
-	if (test_bit(EC_FLAGS_GPE_MASKED, &ec->flags)) {
-		clear_bit(EC_FLAGS_GPE_MASKED, &ec->flags);
-		acpi_ec_enable_gpe(ec, false);
+	if (test_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags)) {
+		clear_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags);
+		if (ec->irq >= 0)
+			enable_irq(ec->irq);
+		else
+			acpi_ec_enable_gpe(ec, false);
 		ec_dbg_drv("Polling disabled");
 	}
 }

@@ -453,7 +459,7 @@ static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec)
 
 static void acpi_ec_submit_query(struct acpi_ec *ec)
 {
-	acpi_ec_mask_gpe(ec);
+	acpi_ec_mask_events(ec);
 	if (!acpi_ec_event_enabled(ec))
 		return;
 	if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {

@@ -469,7 +475,7 @@ static void acpi_ec_complete_query(struct acpi_ec *ec)
 	if (test_and_clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags))
 		ec_dbg_evt("Command(%s) unblocked",
 			   acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
-	acpi_ec_unmask_gpe(ec);
+	acpi_ec_unmask_events(ec);
 }
 
 static inline void __acpi_ec_enable_event(struct acpi_ec *ec)

@@ -647,7 +653,8 @@ static void advance_transaction(struct acpi_ec *ec)
 	 * ensure a hardware STS 0->1 change after this clearing can always
 	 * trigger a GPE interrupt.
 	 */
-	acpi_ec_clear_gpe(ec);
+	if (ec->irq < 0)
+		acpi_ec_clear_gpe(ec);
 	status = acpi_ec_read_status(ec);
 	t = ec->curr;
 	/*

@@ -716,7 +723,7 @@ static void advance_transaction(struct acpi_ec *ec)
 				++t->irq_count;
 			/* Allow triggering on 0 threshold */
 			if (t->irq_count == ec_storm_threshold)
-				acpi_ec_mask_gpe(ec);
+				acpi_ec_mask_events(ec);
 		}
 	}
 out:

@@ -814,7 +821,7 @@ static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
 
 	spin_lock_irqsave(&ec->lock, tmp);
 	if (t->irq_count == ec_storm_threshold)
-		acpi_ec_unmask_gpe(ec);
+		acpi_ec_unmask_events(ec);
 	ec_dbg_req("Command(%s) stopped", acpi_ec_cmd_string(t->command));
 	ec->curr = NULL;
 	/* Disable GPE for command processing (IBF=0/OBF=1) */

@@ -1292,18 +1299,32 @@ static void acpi_ec_event_handler(struct work_struct *work)
 	acpi_ec_check_event(ec);
 }
 
-static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
-	u32 gpe_number, void *data)
+static void acpi_ec_handle_interrupt(struct acpi_ec *ec)
 {
 	unsigned long flags;
-	struct acpi_ec *ec = data;
 
 	spin_lock_irqsave(&ec->lock, flags);
 	advance_transaction(ec);
 	spin_unlock_irqrestore(&ec->lock, flags);
+}
+
+static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
+	u32 gpe_number, void *data)
+{
+	struct acpi_ec *ec = data;
+
+	acpi_ec_handle_interrupt(ec);
 	return ACPI_INTERRUPT_HANDLED;
 }
 
+static irqreturn_t acpi_ec_irq_handler(int irq, void *data)
+{
+	struct acpi_ec *ec = data;
+
+	acpi_ec_handle_interrupt(ec);
+	return IRQ_HANDLED;
+}
+
 /* --------------------------------------------------------------------------
  *                           Address Space Management
  * -------------------------------------------------------------------------- */

@@ -1376,6 +1397,7 @@ static struct acpi_ec *acpi_ec_alloc(void)
 	ec->timestamp = jiffies;
 	ec->busy_polling = true;
 	ec->polling_guard = 0;
+	ec->irq = -1;
 	return ec;
 }
 

@@ -1419,7 +1441,7 @@ ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
 		 * EC.
 		 */
 		ec->gpe = boot_ec->gpe;
-	} else {
+	} else if (!acpi_gbl_reduced_hardware) {
 		/* Get GPE bit assignment (EC events). */
 		/* TODO: Add support for _GPE returning a package */
 		status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);

@@ -1480,7 +1502,8 @@ static int ec_install_handlers(struct acpi_ec *ec, bool handle_events)
 				    NULL, ec, NULL);
 		set_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags);
 	}
-	if (!test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags)) {
+	if (!acpi_gbl_reduced_hardware &&
+	    !test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags)) {
 		status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
 					  ACPI_GPE_EDGE_TRIGGERED,
 					  &acpi_ec_gpe_handler, ec);

@@ -1493,6 +1516,12 @@ static int ec_install_handlers(struct acpi_ec *ec, bool handle_events)
 				acpi_ec_enable_gpe(ec, true);
 		}
 	}
+	if (ec->irq >= 0) {
+		int ret = request_irq(ec->irq, acpi_ec_irq_handler,
+				      IRQF_SHARED, "ACPI EC", ec);
+		if (ret)
+			return ret;
+	}
 	/* EC is fully operational, allow queries */
 	acpi_ec_enable_event(ec);
 

@@ -1521,6 +1550,8 @@ static void ec_remove_handlers(struct acpi_ec *ec)
 	 */
 	acpi_ec_stop(ec, false);
 
+	if (ec->irq >= 0)
+		free_irq(ec->irq, ec);
 	if (test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags)) {
 		if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
 					&acpi_ec_gpe_handler)))

@@ -1611,6 +1642,18 @@ static int acpi_ec_add(struct acpi_device *device)
 			acpi_ec_free(ec);
 			ec = boot_ec;
 		}
+
+		/*
+		 * Reduced hartware platforms use a GpioInt specified in
+		 * _CRS.
+		 */
+		if (acpi_gbl_reduced_hardware) {
+			ret = acpi_dev_gpio_irq_get(device, 0);
+			if (ret == -EPROBE_DEFER)
+				goto err_alloc;
+
+			ec->irq = ret;
+		}
 	}
 
 	ret = acpi_ec_setup(ec, true);

index f4c2fe6be4f2..34c2c85e667e 100644
@@ -166,6 +166,7 @@ static inline void acpi_early_processor_osc(void) {}
 struct acpi_ec {
 	acpi_handle handle;
 	u32 gpe;
+	int irq;
 	unsigned long command_addr;
 	unsigned long data_addr;
 	bool global_lock;