Input: add support for large scancodes

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 ioctls over the entire
sparse scancode space.

To solve those problems, this patch extends the ioctls to allow drivers
handle scancodes up to 32 bytes long (the length could be extended in
the future should such need arise) and allow userspace to query and set
scancode to keycode mappings not only by scancode but also by index.

Compatibility code were also added to handle the old format of
EVIO[CS]GKEYCODE ioctls.

Folded fixes by:
- Dan Carpenter: locking fixes for the original implementation
- Jarod Wilson: fix crash when setting keycode and wiring up get/set
                handlers in original implementation.
- Dmitry Torokhov: rework to consolidate old and new scancode handling,
                   provide options to act either by index or scancode.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

1 files changed, 44 insertions, 11 deletions

diff --git a/include/linux/input.h b/include/linux/input.h
index 789265123531..0057698fd975 100644
--- a/include/linux/input.h
+++ b/include/linux/input.h
@@ -34,7 +34,7 @@ struct input_event {
  * Protocol version.
  */
 
-#define EV_VERSION              0x010000
+#define EV_VERSION              0x010001
 
 /*
  * IOCTLs (0x00 - 0x7f)
@@ -56,12 +56,37 @@ struct input_absinfo {
         __s32 resolution;
 };
 
+/**
+ * struct input_keymap_entry - used by EVIOCGKEYCODE/EVIOCSKEYCODE ioctls
+ * @scancode: scancode represented in machine-endian form.
+ * @len: length of the scancode that resides in @scancode buffer.
+ * @index: index in the keymap, may be used instead of scancode
+ * @flags: allows to specify how kernel should handle the request. For
+ *      example, setting INPUT_KEYMAP_BY_INDEX flag indicates that kernel
+ *      should perform lookup in keymap by @index instead of @scancode
+ * @keycode: key code assigned to this scancode
+ *
+ * The structure is used to retrieve and modify keymap data. Users have
+ * option of performing lookup either by @scancode itself or by @index
+ * in keymap entry. EVIOCGKEYCODE will also return scancode or index
+ * (depending on which element was used to perform lookup).
+ */
+struct input_keymap_entry {
+#define INPUT_KEYMAP_BY_INDEX   (1 << 0)
+        __u8  flags;
+        __u8  len;
+        __u16 index;
+        __u32 keycode;
+        __u8  scancode[32];
+};
+
 #define EVIOCGVERSION           _IOR('E', 0x01, int)                    /* get driver version */
 #define EVIOCGID                _IOR('E', 0x02, struct input_id)        /* get device ID */
 #define EVIOCGREP               _IOR('E', 0x03, unsigned int[2])        /* get repeat settings */
 #define EVIOCSREP               _IOW('E', 0x03, unsigned int[2])        /* set repeat settings */
-#define EVIOCGKEYCODE           _IOR('E', 0x04, unsigned int[2])        /* get keycode */
-#define EVIOCSKEYCODE           _IOW('E', 0x04, unsigned int[2])        /* set keycode */
+
+#define EVIOCGKEYCODE           _IOR('E', 0x04, struct input_keymap_entry)      /* get keycode */
+#define EVIOCSKEYCODE           _IOW('E', 0x04, struct input_keymap_entry)      /* set keycode */
 
 #define EVIOCGNAME(len)         _IOC(_IOC_READ, 'E', 0x06, len)         /* get device name */
 #define EVIOCGPHYS(len)         _IOC(_IOC_READ, 'E', 0x07, len)         /* get physical location */
@@ -73,8 +98,8 @@ struct input_absinfo {
 #define EVIOCGSW(len)           _IOC(_IOC_READ, 'E', 0x1b, len)         /* get all switch states */
 
 #define EVIOCGBIT(ev,len)       _IOC(_IOC_READ, 'E', 0x20 + ev, len)    /* get event bits */
-#define EVIOCGABS(abs)          _IOR('E', 0x40 + abs, struct input_absinfo)             /* get abs value/limits */
-#define EVIOCSABS(abs)          _IOW('E', 0xc0 + abs, struct input_absinfo)             /* set abs value/limits */
+#define EVIOCGABS(abs)          _IOR('E', 0x40 + abs, struct input_absinfo)     /* get abs value/limits */
+#define EVIOCSABS(abs)          _IOW('E', 0xc0 + abs, struct input_absinfo)     /* set abs value/limits */
 
 #define EVIOCSFF                _IOC(_IOC_WRITE, 'E', 0x80, sizeof(struct ff_effect))   /* send a force effect to a force feedback device */
 #define EVIOCRMFF               _IOW('E', 0x81, int)                    /* Erase a force effect */
@@ -1088,13 +1113,13 @@ struct input_mt_slot {
  * @keycodemax: size of keycode table
  * @keycodesize: size of elements in keycode table
  * @keycode: map of scancodes to keycodes for this device
+ * @getkeycode: optional legacy method to retrieve current keymap.
  * @setkeycode: optional method to alter current keymap, used to implement
  *      sparse keymaps. If not supplied default mechanism will be used.
  *      The method is being called while holding event_lock and thus must
  *      not sleep
- * @getkeycode: optional method to retrieve current keymap. If not supplied
- *      default mechanism will be used. The method is being called while
- *      holding event_lock and thus must not sleep
+ * @getkeycode_new: transition method
+ * @setkeycode_new: transition method
  * @ff: force feedback structure associated with the device if device
  *      supports force feedback effects
  * @repeat_key: stores key code of the last key pressed; used to implement
@@ -1168,10 +1193,16 @@ struct input_dev {
         unsigned int keycodemax;
         unsigned int keycodesize;
         void *keycode;
+
         int (*setkeycode)(struct input_dev *dev,
                           unsigned int scancode, unsigned int keycode);
         int (*getkeycode)(struct input_dev *dev,
                           unsigned int scancode, unsigned int *keycode);
+        int (*setkeycode_new)(struct input_dev *dev,
+                              const struct input_keymap_entry *ke,
+                              unsigned int *old_keycode);
+        int (*getkeycode_new)(struct input_dev *dev,
+                              struct input_keymap_entry *ke);
 
         struct ff_device *ff;
 
@@ -1478,10 +1509,12 @@ INPUT_GENERATE_ABS_ACCESSORS(fuzz, fuzz)
 INPUT_GENERATE_ABS_ACCESSORS(flat, flat)
 INPUT_GENERATE_ABS_ACCESSORS(res, resolution)
 
-int input_get_keycode(struct input_dev *dev,
-                      unsigned int scancode, unsigned int *keycode);
+int input_scancode_to_scalar(const struct input_keymap_entry *ke,
+                             unsigned int *scancode);
+
+int input_get_keycode(struct input_dev *dev, struct input_keymap_entry *ke);
 int input_set_keycode(struct input_dev *dev,
-                      unsigned int scancode, unsigned int keycode);
+                      const struct input_keymap_entry *ke);
 
 extern struct class input_class;