V4L/DVB: input: Add support for EVIO[CS]GKEYCODEBIG

Several devices use a high number of bits for scancodes. One important
group is the Remote Controllers. Some new protocols like RC-6 define a
scancode space of 64 bits.

The current EVIO[CS]GKEYCODE ioctls allow replace the scancode/keycode
translation tables, but it is limited to up to 32 bits for scancode.

Also, if userspace wants to clean the existing table, replacing it by
a new one, it needs to run a loop calling the old ioctls, over the
entire sparsed scancode userspace.

To solve those problems, this patch introduces two new ioctls:
	EVIOCGKEYCODEBIG - reads a scancode from the translation table;
	EVIOSGKEYCODEBIG - writes a scancode into the translation table.

The EVIOSGKEYCODEBIG can also be used to cleanup the translation entries
by associating KEY_RESERVED to a scancode.

EVIOCGKEYCODEBIG uses kt_entry::index field in order to retrieve a keycode
from the table. This field is unused on EVIOSGKEYCODEBIG.

By default, kernel will implement a default handler that will work with
both EVIO[CS]GKEYCODEBIG and the legacy EVIO[CS]GKEYCODE ioctls.

Compatibility code were also added to allow drivers that implement
only the ops handler for EVIO[CS]GKEYCODE to keep working.

Userspace compatibility for EVIO[CS]GKEYCODE is also granted: the evdev/input
ioctl handler will automatically map those ioctls with the new
getkeycodebig()/setkeycodebig() operations to handle a request using the
legacy API.

So, new drivers should only implement the EVIO[CS]GKEYCODEBIG operation
handlers: getkeycodebig()/setkeycodebig().

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 235 insertions, 25 deletions

diff --git a/drivers/input/input.c b/drivers/input/input.c
index 86cb2d2196ff..d2bb5b5978a3 100644
--- a/drivers/input/input.c
+++ b/drivers/input/input.c
@@ -551,6 +551,11 @@ static void input_disconnect_device(struct input_dev *dev)
 	spin_unlock_irq(&dev->event_lock);
 }
 
+/*
+ * Those routines handle the default case where no [gs]etkeycode() is
+ * defined. In this case, an array indexed by the scancode is used.
+ */
+
 static int input_fetch_keycode(struct input_dev *dev, int scancode)
 {
 	switch (dev->keycodesize) {
@@ -565,25 +570,74 @@ static int input_fetch_keycode(struct input_dev *dev, int scancode)
 	}
 }
 
-static int input_default_getkeycode(struct input_dev *dev,
-				    int scancode, int *keycode)
+/*
+ * Supports only 8, 16 and 32 bit scancodes. It wouldn't be that
+ * hard to write some machine-endian logic to support 24 bit scancodes,
+ * but it seemed overkill. It should also be noticed that, since there
+ * are, in general, less than 256 scancodes sparsed into the scancode
+ * space, even with 16 bits, the codespace is sparsed, with leads into
+ * memory and code ineficiency, when retrieving the entire scancode
+ * space.
+ * So, it is highly recommended to implement getkeycodebig/setkeycodebig
+ * instead of using a normal table approach, when more than 8 bits is
+ * needed for the scancode.
+ */
+static int input_fetch_scancode(struct keycode_table_entry *kt_entry,
+				u32 *scancode)
+{
+	switch (kt_entry->len) {
+	case 1:
+		*scancode = *((u8 *)kt_entry->scancode);
+		break;
+	case 2:
+		*scancode = *((u16 *)kt_entry->scancode);
+		break;
+	case 4:
+		*scancode = *((u32 *)kt_entry->scancode);
+		break;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+
+static int input_default_getkeycode_from_index(struct input_dev *dev,
+				    struct keycode_table_entry *kt_entry)
 {
+	u32 scancode = kt_entry->index;
+
 	if (!dev->keycodesize)
 		return -EINVAL;
 
 	if (scancode >= dev->keycodemax)
 		return -EINVAL;
 
-	*keycode = input_fetch_keycode(dev, scancode);
+	kt_entry->keycode = input_fetch_keycode(dev, scancode);
+	memcpy(kt_entry->scancode, &scancode, 4);
 
 	return 0;
 }
 
+static int input_default_getkeycode_from_scancode(struct input_dev *dev,
+				    struct keycode_table_entry *kt_entry)
+{
+	if (input_fetch_scancode(kt_entry, &kt_entry->index))
+		return -EINVAL;
+
+	return input_default_getkeycode_from_index(dev, kt_entry);
+}
+
+
 static int input_default_setkeycode(struct input_dev *dev,
-				    int scancode, int keycode)
+				    struct keycode_table_entry *kt_entry)
 {
 	int old_keycode;
 	int i;
+	u32 scancode;
+
+	if (input_fetch_scancode(kt_entry, &scancode))
+		return -EINVAL;
 
 	if (scancode >= dev->keycodemax)
 		return -EINVAL;
@@ -591,32 +645,33 @@ static int input_default_setkeycode(struct input_dev *dev,
 	if (!dev->keycodesize)
 		return -EINVAL;
 
-	if (dev->keycodesize < sizeof(keycode) && (keycode >> (dev->keycodesize * 8)))
+	if (dev->keycodesize < sizeof(dev->keycode) &&
+	    (kt_entry->keycode >> (dev->keycodesize * 8)))
 		return -EINVAL;
 
 	switch (dev->keycodesize) {
 		case 1: {
 			u8 *k = (u8 *)dev->keycode;
 			old_keycode = k[scancode];
-			k[scancode] = keycode;
+			k[scancode] = kt_entry->keycode;
 			break;
 		}
 		case 2: {
 			u16 *k = (u16 *)dev->keycode;
 			old_keycode = k[scancode];
-			k[scancode] = keycode;
+			k[scancode] = kt_entry->keycode;
 			break;
 		}
 		default: {
 			u32 *k = (u32 *)dev->keycode;
 			old_keycode = k[scancode];
-			k[scancode] = keycode;
+			k[scancode] = kt_entry->keycode;
 			break;
 		}
 	}
 
 	clear_bit(old_keycode, dev->keybit);
-	set_bit(keycode, dev->keybit);
+	set_bit(kt_entry->keycode, dev->keybit);
 
 	for (i = 0; i < dev->keycodemax; i++) {
 		if (input_fetch_keycode(dev, i) == old_keycode) {
@@ -629,6 +684,109 @@ static int input_default_setkeycode(struct input_dev *dev,
 }
 
 /**
+ * input_get_keycode_big - retrieve keycode currently mapped to a given scancode
+ * @dev: input device which keymap is being queried
+ * @kt_entry: keytable entry
+ *
+ * This function should be called by anyone interested in retrieving current
+ * keymap. Presently evdev handlers use it.
+ */
+int input_get_keycode_big(struct input_dev *dev,
+			  struct keycode_table_entry *kt_entry)
+{
+	if (dev->getkeycode) {
+		u32 scancode = kt_entry->index;
+
+		/*
+		 * Support for legacy drivers, that don't implement the new
+		 * ioctls
+		 */
+		memcpy(kt_entry->scancode, &scancode, 4);
+		return dev->getkeycode(dev, scancode,
+				       &kt_entry->keycode);
+	} else
+		return dev->getkeycodebig_from_index(dev, kt_entry);
+}
+EXPORT_SYMBOL(input_get_keycode_big);
+
+/**
+ * input_set_keycode_big - attribute a keycode to a given scancode
+ * @dev: input device which keymap is being queried
+ * @kt_entry: keytable entry
+ *
+ * This function should be called by anyone needing to update current
+ * keymap. Presently keyboard and evdev handlers use it.
+ */
+int input_set_keycode_big(struct input_dev *dev,
+			  struct keycode_table_entry *kt_entry)
+{
+	unsigned long flags;
+	int old_keycode;
+	int retval = -EINVAL;
+	u32 uninitialized_var(scancode);
+
+	if (kt_entry->keycode < 0 || kt_entry->keycode > KEY_MAX)
+		return -EINVAL;
+
+	spin_lock_irqsave(&dev->event_lock, flags);
+
+	/*
+	 * We need to know the old scancode, in order to generate a
+	 * keyup effect, if the set operation happens successfully
+	 */
+	if (dev->getkeycode) {
+		/*
+		 * Support for legacy drivers, that don't implement the new
+		 * ioctls
+		 */
+		if (!dev->setkeycode)
+			goto out;
+
+		if (input_fetch_scancode(kt_entry, &scancode))
+			return -EINVAL;
+
+		retval = dev->getkeycode(dev, scancode,
+					 &old_keycode);
+	} else {
+		int new_keycode = kt_entry->keycode;
+
+		retval = dev->getkeycodebig_from_scancode(dev, kt_entry);
+		old_keycode = kt_entry->keycode;
+		kt_entry->keycode = new_keycode;
+	}
+
+	if (retval)
+		goto out;
+
+	if (dev->getkeycode)
+		retval = dev->setkeycode(dev, scancode,
+					 kt_entry->keycode);
+	else
+		retval = dev->setkeycodebig(dev, kt_entry);
+	if (retval)
+		goto out;
+
+	/*
+	 * Simulate keyup event if keycode is not present
+	 * in the keymap anymore
+	 */
+	if (test_bit(EV_KEY, dev->evbit) &&
+	    !is_event_supported(old_keycode, dev->keybit, KEY_MAX) &&
+	    __test_and_clear_bit(old_keycode, dev->key)) {
+
+		input_pass_event(dev, EV_KEY, old_keycode, 0);
+		if (dev->sync)
+			input_pass_event(dev, EV_SYN, SYN_REPORT, 1);
+	}
+
+ out:
+	spin_unlock_irqrestore(&dev->event_lock, flags);
+
+	return retval;
+}
+EXPORT_SYMBOL(input_set_keycode_big);
+
+/**
  * input_get_keycode - retrieve keycode currently mapped to a given scancode
  * @dev: input device which keymap is being queried
  * @scancode: scancode (or its equivalent for device in question) for which
@@ -640,10 +798,31 @@ static int input_default_setkeycode(struct input_dev *dev,
  */
 int input_get_keycode(struct input_dev *dev, int scancode, int *keycode)
 {
-	if (scancode < 0)
-		return -EINVAL;
+	if (dev->getkeycode) {
+		/*
+		 * Use the legacy calls
+		 */
+		return dev->getkeycode(dev, scancode, keycode);
+	} else {
+		int retval;
+		struct keycode_table_entry kt_entry;
 
-	return dev->getkeycode(dev, scancode, keycode);
+		/*
+		 * Userspace is using a legacy call with a driver ported
+		 * to the new way. This is a bad idea with long sparsed
+		 * tables, since lots of the retrieved values will be in
+		 * blank. Also, it makes sense only if the table size is
+		 * lower than 2^32.
+		 */
+		memset(&kt_entry, 0, sizeof(kt_entry));
+		kt_entry.len = 4;
+		kt_entry.index = scancode;
+
+		retval = dev->getkeycodebig_from_index(dev, &kt_entry);
+
+		*keycode = kt_entry.keycode;
+		return retval;
+	}
 }
 EXPORT_SYMBOL(input_get_keycode);
 
@@ -662,21 +841,46 @@ int input_set_keycode(struct input_dev *dev, int scancode, int keycode)
 	int old_keycode;
 	int retval;
 
-	if (scancode < 0)
-		return -EINVAL;
-
 	if (keycode < 0 || keycode > KEY_MAX)
 		return -EINVAL;
 
 	spin_lock_irqsave(&dev->event_lock, flags);
 
-	retval = dev->getkeycode(dev, scancode, &old_keycode);
-	if (retval)
-		goto out;
+	if (dev->getkeycode) {
+		/*
+		 * Use the legacy calls
+		 */
+		retval = dev->getkeycode(dev, scancode, &old_keycode);
+		if (retval)
+			goto out;
 
-	retval = dev->setkeycode(dev, scancode, keycode);
-	if (retval)
-		goto out;
+		retval = dev->setkeycode(dev, scancode, keycode);
+		if (retval)
+			goto out;
+	} else {
+		struct keycode_table_entry kt_entry;
+
+		/*
+		 * Userspace is using a legacy call with a driver ported
+		 * to the new way. This is a bad idea with long sparsed
+		 * tables, since lots of the retrieved values will be in
+		 * blank. Also, it makes sense only if the table size is
+		 * lower than 2^32.
+		 */
+		memset(&kt_entry, 0, sizeof(kt_entry));
+		kt_entry.len = 4;
+		kt_entry.scancode = (char *)&scancode;
+
+		retval = dev->getkeycodebig_from_scancode(dev, &kt_entry);
+		if (retval)
+			goto out;
+
+		kt_entry.keycode = keycode;
+
+		retval = dev->setkeycodebig(dev, &kt_entry);
+		if (retval)
+			goto out;
+	}
 
 	/*
 	 * Simulate keyup event if keycode is not present
@@ -1585,11 +1789,17 @@ int input_register_device(struct input_dev *dev)
 		dev->rep[REP_PERIOD] = 33;
 	}
 
-	if (!dev->getkeycode)
-		dev->getkeycode = input_default_getkeycode;
+	if (!dev->getkeycode) {
+		if (!dev->getkeycodebig_from_index)
+			dev->getkeycodebig_from_index = input_default_getkeycode_from_index;
+		if (!dev->getkeycodebig_from_scancode)
+			dev->getkeycodebig_from_scancode = input_default_getkeycode_from_scancode;
+	}
 
-	if (!dev->setkeycode)
-		dev->setkeycode = input_default_setkeycode;
+	if (dev->setkeycode) {
+		if (!dev->setkeycodebig)
+			dev->setkeycodebig = input_default_setkeycode;
+	}
 
 	dev_set_name(&dev->dev, "input%ld",
 		     (unsigned long) atomic_inc_return(&input_no) - 1);