1 files changed, 71 insertions, 32 deletions

diff --git a/drivers/input/serio/libps2.c b/drivers/input/serio/libps2.c
index 82befae4dab0..f05c407b31f3 100644
--- a/drivers/input/serio/libps2.c
+++ b/drivers/input/serio/libps2.c
@@ -26,35 +26,63 @@ MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
 MODULE_DESCRIPTION("PS/2 driver library");
 MODULE_LICENSE("GPL");
 
-static int ps2_do_sendbyte(struct ps2dev *ps2dev, u8 byte, unsigned int timeout)
+static int ps2_do_sendbyte(struct ps2dev *ps2dev, u8 byte,
+			   unsigned int timeout, unsigned int max_attempts)
+	__releases(&ps2dev->serio->lock) __acquires(&ps2dev->serio->lock)
 {
+	int attempt = 0;
 	int error;
 
-	serio_pause_rx(ps2dev->serio);
-	ps2dev->nak = 1;
-	ps2dev->flags |= PS2_FLAG_ACK;
-	serio_continue_rx(ps2dev->serio);
+	lockdep_assert_held(&ps2dev->serio->lock);
 
-	error = serio_write(ps2dev->serio, byte);
-	if (error)
-		dev_dbg(&ps2dev->serio->dev,
-			"failed to write %#02x: %d\n", byte, error);
-	else
-		wait_event_timeout(ps2dev->wait,
-				   !(ps2dev->flags & PS2_FLAG_ACK),
-				   msecs_to_jiffies(timeout));
+	do {
+		ps2dev->nak = 1;
+		ps2dev->flags |= PS2_FLAG_ACK;
+
+		serio_continue_rx(ps2dev->serio);
+
+		error = serio_write(ps2dev->serio, byte);
+		if (error)
+			dev_dbg(&ps2dev->serio->dev,
+				"failed to write %#02x: %d\n", byte, error);
+		else
+			wait_event_timeout(ps2dev->wait,
+					   !(ps2dev->flags & PS2_FLAG_ACK),
+					   msecs_to_jiffies(timeout));
+
+		serio_pause_rx(ps2dev->serio);
+	} while (ps2dev->nak == PS2_RET_NAK && ++attempt < max_attempts);
 
-	serio_pause_rx(ps2dev->serio);
 	ps2dev->flags &= ~PS2_FLAG_ACK;
-	serio_continue_rx(ps2dev->serio);
 
-	return -ps2dev->nak;
+	if (!error) {
+		switch (ps2dev->nak) {
+		case 0:
+			break;
+		case PS2_RET_NAK:
+			error = -EAGAIN;
+			break;
+		case PS2_RET_ERR:
+			error = -EPROTO;
+			break;
+		default:
+			error = -EIO;
+			break;
+		}
+	}
+
+	if (error || attempt > 1)
+		dev_dbg(&ps2dev->serio->dev,
+			"%02x - %d (%x), attempt %d\n",
+			byte, error, ps2dev->nak, attempt);
+
+	return error;
 }
 
 /*
  * ps2_sendbyte() sends a byte to the device and waits for acknowledge.
- * It doesn't handle retransmission, though it could - because if there
- * is a need for retransmissions device has to be replaced anyway.
+ * It doesn't handle retransmission, the caller is expected to handle
+ * it when needed.
  *
  * ps2_sendbyte() can only be called from a process context.
  */
@@ -63,9 +91,13 @@ int ps2_sendbyte(struct ps2dev *ps2dev, u8 byte, unsigned int timeout)
 {
 	int retval;
 
-	retval = ps2_do_sendbyte(ps2dev, byte, timeout);
+	serio_pause_rx(ps2dev->serio);
+
+	retval = ps2_do_sendbyte(ps2dev, byte, timeout, 1);
 	dev_dbg(&ps2dev->serio->dev, "%02x - %x\n", byte, ps2dev->nak);
 
+	serio_continue_rx(ps2dev->serio);
+
 	return retval;
 }
 EXPORT_SYMBOL(ps2_sendbyte);
@@ -200,48 +232,48 @@ int __ps2_command(struct ps2dev *ps2dev, u8 *param, unsigned int command)
 	unsigned int timeout;
 	unsigned int send = (command >> 12) & 0xf;
 	unsigned int receive = (command >> 8) & 0xf;
-	int rc = -1;
+	int rc;
 	int i;
 	u8 send_param[16];
 
 	if (receive > sizeof(ps2dev->cmdbuf)) {
 		WARN_ON(1);
-		return -1;
+		return -EINVAL;
 	}
 
 	if (send && !param) {
 		WARN_ON(1);
-		return -1;
+		return -EINVAL;
 	}
 
 	memcpy(send_param, param, send);
 
 	serio_pause_rx(ps2dev->serio);
+
 	ps2dev->flags = command == PS2_CMD_GETID ? PS2_FLAG_WAITID : 0;
 	ps2dev->cmdcnt = receive;
 	if (receive && param)
 		for (i = 0; i < receive; i++)
 			ps2dev->cmdbuf[(receive - 1) - i] = param[i];
-	serio_continue_rx(ps2dev->serio);
 
 	/*
 	 * Some devices (Synaptics) peform the reset before
 	 * ACKing the reset command, and so it can take a long
 	 * time before the ACK arrives.
 	 */
-	if (ps2_do_sendbyte(ps2dev, command & 0xff,
-			    command == PS2_CMD_RESET_BAT ? 1000 : 200)) {
-		serio_pause_rx(ps2dev->serio);
+	rc = ps2_do_sendbyte(ps2dev, command & 0xff,
+			     command == PS2_CMD_RESET_BAT ? 1000 : 200, 2);
+	if (rc)
 		goto out_reset_flags;
-	}
 
 	for (i = 0; i < send; i++) {
-		if (ps2_do_sendbyte(ps2dev, param[i], 200)) {
-			serio_pause_rx(ps2dev->serio);
+		rc = ps2_do_sendbyte(ps2dev, param[i], 200, 2);
+		if (rc)
 			goto out_reset_flags;
-		}
 	}
 
+	serio_continue_rx(ps2dev->serio);
+
 	/*
 	 * The reset command takes a long time to execute.
 	 */
@@ -263,8 +295,11 @@ int __ps2_command(struct ps2dev *ps2dev, u8 *param, unsigned int command)
 		for (i = 0; i < receive; i++)
 			param[i] = ps2dev->cmdbuf[(receive - 1) - i];
 
-	if (ps2dev->cmdcnt && (command != PS2_CMD_RESET_BAT || ps2dev->cmdcnt != 1))
+	if (ps2dev->cmdcnt &&
+	    (command != PS2_CMD_RESET_BAT || ps2dev->cmdcnt != 1)) {
+		rc = -EPROTO;
 		goto out_reset_flags;
+	}
 
 	rc = 0;
 
@@ -278,7 +313,11 @@ int __ps2_command(struct ps2dev *ps2dev, u8 *param, unsigned int command)
 		ps2dev->nak, ps2dev->flags,
 		receive, param ?: send_param);
 
-	return rc;
+	/*
+	 * ps_command() handles resends itself, so do not leak -EAGAIN
+	 * to the callers.
+	 */
+	return rc != -EAGAIN ? rc : -EPROTO;
 }
 EXPORT_SYMBOL(__ps2_command);