1 files changed, 79 insertions, 9 deletions

diff --git a/drivers/input/serio/i8042.c b/drivers/input/serio/i8042.c
index 1df02d25aca..d84a36e545f 100644
--- a/drivers/input/serio/i8042.c
+++ b/drivers/input/serio/i8042.c
@@ -126,6 +126,8 @@ static unsigned char i8042_suppress_kbd_ack;
 static struct platform_device *i8042_platform_device;
 
 static irqreturn_t i8042_interrupt(int irq, void *dev_id);
+static bool (*i8042_platform_filter)(unsigned char data, unsigned char str,
+				     struct serio *serio);
 
 void i8042_lock_chip(void)
 {
@@ -139,6 +141,48 @@ void i8042_unlock_chip(void)
 }
 EXPORT_SYMBOL(i8042_unlock_chip);
 
+int i8042_install_filter(bool (*filter)(unsigned char data, unsigned char str,
+					struct serio *serio))
+{
+	unsigned long flags;
+	int ret = 0;
+
+	spin_lock_irqsave(&i8042_lock, flags);
+
+	if (i8042_platform_filter) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	i8042_platform_filter = filter;
+
+out:
+	spin_unlock_irqrestore(&i8042_lock, flags);
+	return ret;
+}
+EXPORT_SYMBOL(i8042_install_filter);
+
+int i8042_remove_filter(bool (*filter)(unsigned char data, unsigned char str,
+				       struct serio *port))
+{
+	unsigned long flags;
+	int ret = 0;
+
+	spin_lock_irqsave(&i8042_lock, flags);
+
+	if (i8042_platform_filter != filter) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	i8042_platform_filter = NULL;
+
+out:
+	spin_unlock_irqrestore(&i8042_lock, flags);
+	return ret;
+}
+EXPORT_SYMBOL(i8042_remove_filter);
+
 /*
  * The i8042_wait_read() and i8042_wait_write functions wait for the i8042 to
  * be ready for reading values from it / writing values to it.
@@ -369,6 +413,31 @@ static void i8042_stop(struct serio *serio)
 }
 
 /*
+ * i8042_filter() filters out unwanted bytes from the input data stream.
+ * It is called from i8042_interrupt and thus is running with interrupts
+ * off and i8042_lock held.
+ */
+static bool i8042_filter(unsigned char data, unsigned char str,
+			 struct serio *serio)
+{
+	if (unlikely(i8042_suppress_kbd_ack)) {
+		if ((~str & I8042_STR_AUXDATA) &&
+		    (data == 0xfa || data == 0xfe)) {
+			i8042_suppress_kbd_ack--;
+			dbg("Extra keyboard ACK - filtered out\n");
+			return true;
+		}
+	}
+
+	if (i8042_platform_filter && i8042_platform_filter(data, str, serio)) {
+		dbg("Filtered out by platfrom filter\n");
+		return true;
+	}
+
+	return false;
+}
+
+/*
  * i8042_interrupt() is the most important function in this driver -
  * it handles the interrupts from the i8042, and sends incoming bytes
  * to the upper layers.
@@ -377,13 +446,16 @@ static void i8042_stop(struct serio *serio)
 static irqreturn_t i8042_interrupt(int irq, void *dev_id)
 {
 	struct i8042_port *port;
+	struct serio *serio;
 	unsigned long flags;
 	unsigned char str, data;
 	unsigned int dfl;
 	unsigned int port_no;
+	bool filtered;
 	int ret = 1;
 
 	spin_lock_irqsave(&i8042_lock, flags);
+
 	str = i8042_read_status();
 	if (unlikely(~str & I8042_STR_OBF)) {
 		spin_unlock_irqrestore(&i8042_lock, flags);
@@ -391,8 +463,8 @@ static irqreturn_t i8042_interrupt(int irq, void *dev_id)
 		ret = 0;
 		goto out;
 	}
+
 	data = i8042_read_data();
-	spin_unlock_irqrestore(&i8042_lock, flags);
 
 	if (i8042_mux_present && (str & I8042_STR_AUXDATA)) {
 		static unsigned long last_transmit;
@@ -441,21 +513,19 @@ static irqreturn_t i8042_interrupt(int irq, void *dev_id)
 	}
 
 	port = &i8042_ports[port_no];
+	serio = port->exists ? port->serio : NULL;
 
 	dbg("%02x <- i8042 (interrupt, %d, %d%s%s)",
 	    data, port_no, irq,
 	    dfl & SERIO_PARITY ? ", bad parity" : "",
 	    dfl & SERIO_TIMEOUT ? ", timeout" : "");
 
-	if (unlikely(i8042_suppress_kbd_ack))
-		if (port_no == I8042_KBD_PORT_NO &&
-		    (data == 0xfa || data == 0xfe)) {
-			i8042_suppress_kbd_ack--;
-			goto out;
-		}
+	filtered = i8042_filter(data, str, serio);
+
+	spin_unlock_irqrestore(&i8042_lock, flags);
 
-	if (likely(port->exists))
-		serio_interrupt(port->serio, data, dfl);
+	if (likely(port->exists && !filtered))
+		serio_interrupt(serio, data, dfl);
 
  out:
 	return IRQ_RETVAL(ret);