V4L/DVB (13542): ir-keytable: Allow dynamic table change
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/common/ir-keytable.c b/drivers/media/common/ir-keytable.c
index b06f023..26ce5bc 100644
--- a/drivers/media/common/ir-keytable.c
+++ b/drivers/media/common/ir-keytable.c
@@ -8,6 +8,7 @@
#include <media/ir-common.h>
#define IR_TAB_MIN_SIZE 32
+#define IR_TAB_MAX_SIZE 1024
/**
* ir_seek_table() - returns the element order on the table
@@ -121,7 +122,154 @@
return 0;
}
- return -EINVAL;
+ /*
+ * Scancode not found and table can't be expanded
+ */
+ if (elem < 0 && rc_tab->size == IR_TAB_MAX_SIZE)
+ return -EINVAL;
+
+ /*
+ * If is there extra space, returns KEY_RESERVED,
+ * otherwise, input core won't let ir_setkeycode to work
+ */
+ *keycode = KEY_RESERVED;
+ return 0;
+}
+
+
+/**
+ * ir_is_resize_needed() - Check if the table needs rezise
+ * @table: keycode table that may need to resize
+ * @n_elems: minimum number of entries to store keycodes
+ *
+ * Considering that kmalloc uses power of two storage areas, this
+ * routine detects if the real alloced size will change. If not, it
+ * just returns without doing nothing. Otherwise, it will extend or
+ * reduce the table size to meet the new needs.
+ *
+ * It returns 0 if no resize is needed, 1 otherwise.
+ */
+static int ir_is_resize_needed(struct ir_scancode_table *table, int n_elems)
+{
+ int cur_size = ir_roundup_tablesize(table->size);
+ int new_size = ir_roundup_tablesize(n_elems);
+
+ if (cur_size == new_size)
+ return 0;
+
+ /* Resize is needed */
+ return 1;
+}
+
+/**
+ * ir_delete_key() - remove a keycode from the table
+ * @rc_tab: keycode table
+ * @elem: element to be removed
+ *
+ */
+static void ir_delete_key(struct ir_scancode_table *rc_tab, int elem)
+{
+ unsigned long flags = 0;
+ int newsize = rc_tab->size - 1;
+ int resize = ir_is_resize_needed(rc_tab, newsize);
+ struct ir_scancode *oldkeymap = rc_tab->scan;
+ struct ir_scancode *newkeymap;
+
+ if (resize) {
+ newkeymap = kzalloc(ir_roundup_tablesize(newsize) *
+ sizeof(*newkeymap), GFP_ATOMIC);
+
+ /* There's no memory for resize. Keep the old table */
+ if (!newkeymap)
+ resize = 0;
+ }
+
+ if (!resize) {
+ newkeymap = oldkeymap;
+
+ /* We'll modify the live table. Lock it */
+ spin_lock_irqsave(&rc_tab->lock, flags);
+ }
+
+ /*
+ * Copy the elements before the one that will be deleted
+ * if (!resize), both oldkeymap and newkeymap points
+ * to the same place, so, there's no need to copy
+ */
+ if (resize && elem > 0)
+ memcpy(newkeymap, oldkeymap,
+ elem * sizeof(*newkeymap));
+
+ /*
+ * Copy the other elements overwriting the element to be removed
+ * This operation applies to both resize and non-resize case
+ */
+ if (elem < newsize)
+ memcpy(&newkeymap[elem], &oldkeymap[elem + 1],
+ (newsize - elem) * sizeof(*newkeymap));
+
+ if (resize) {
+ /*
+ * As the copy happened to a temporary table, only here
+ * it needs to lock while replacing the table pointers
+ * to use the new table
+ */
+ spin_lock_irqsave(&rc_tab->lock, flags);
+ rc_tab->size = newsize;
+ rc_tab->scan = newkeymap;
+ spin_unlock_irqrestore(&rc_tab->lock, flags);
+
+ /* Frees the old keytable */
+ kfree(oldkeymap);
+ } else {
+ rc_tab->size = newsize;
+ spin_unlock_irqrestore(&rc_tab->lock, flags);
+ }
+}
+
+/**
+ * ir_insert_key() - insert a keycode at the table
+ * @rc_tab: keycode table
+ * @scancode: the desired scancode
+ * @keycode: the keycode to be retorned.
+ *
+ */
+static int ir_insert_key(struct ir_scancode_table *rc_tab,
+ int scancode, int keycode)
+{
+ unsigned long flags;
+ int elem = rc_tab->size;
+ int newsize = rc_tab->size + 1;
+ int resize = ir_is_resize_needed(rc_tab, newsize);
+ struct ir_scancode *oldkeymap = rc_tab->scan;
+ struct ir_scancode *newkeymap;
+
+ if (resize) {
+ newkeymap = kzalloc(ir_roundup_tablesize(newsize) *
+ sizeof(*newkeymap), GFP_ATOMIC);
+ if (!newkeymap)
+ return -ENOMEM;
+
+ memcpy(newkeymap, oldkeymap,
+ rc_tab->size * sizeof(*newkeymap));
+ } else
+ newkeymap = oldkeymap;
+
+ /* Stores the new code at the table */
+ IR_dprintk(1, "#%d: New scan 0x%04x with key 0x%04x\n",
+ rc_tab->size, scancode, keycode);
+
+ spin_lock_irqsave(&rc_tab->lock, flags);
+ rc_tab->size = newsize;
+ if (resize) {
+ rc_tab->scan = newkeymap;
+ kfree(oldkeymap);
+ }
+ newkeymap[elem].scancode = scancode;
+ newkeymap[elem].keycode = keycode;
+ spin_unlock_irqrestore(&rc_tab->lock, flags);
+
+ return 0;
}
/**
@@ -142,20 +290,59 @@
struct ir_scancode *keymap = rc_tab->scan;
unsigned long flags;
- /* Search if it is replacing an existing keycode */
+ /*
+ * Handle keycode table deletions
+ *
+ * If userspace is adding a KEY_UNKNOWN or KEY_RESERVED,
+ * deal as a trial to remove an existing scancode attribution
+ * if table become too big, reduce it to save space
+ */
+ if (keycode == KEY_UNKNOWN || keycode == KEY_RESERVED) {
+ rc = ir_seek_table(rc_tab, scancode);
+ if (rc < 0)
+ return 0;
+
+ IR_dprintk(1, "#%d: Deleting scan 0x%04x\n", rc, scancode);
+ clear_bit(keymap[rc].keycode, dev->keybit);
+ ir_delete_key(rc_tab, rc);
+
+ return 0;
+ }
+
+ /*
+ * Handle keycode replacements
+ *
+ * If the scancode exists, just replace by the new value
+ */
rc = ir_seek_table(rc_tab, scancode);
- if (rc <0)
+ if (rc >= 0) {
+ IR_dprintk(1, "#%d: Replacing scan 0x%04x with key 0x%04x\n",
+ rc, scancode, keycode);
+
+ clear_bit(keymap[rc].keycode, dev->keybit);
+
+ spin_lock_irqsave(&rc_tab->lock, flags);
+ keymap[rc].keycode = keycode;
+ spin_unlock_irqrestore(&rc_tab->lock, flags);
+
+ set_bit(keycode, dev->keybit);
+
+ return 0;
+ }
+
+ /*
+ * Handle new scancode inserts
+ *
+ * reallocate table if needed and insert a new keycode
+ */
+
+ /* Avoid growing the table indefinitely */
+ if (rc_tab->size + 1 > IR_TAB_MAX_SIZE)
+ return -EINVAL;
+
+ rc = ir_insert_key(rc_tab, scancode, keycode);
+ if (rc < 0)
return rc;
-
- IR_dprintk(1, "#%d: Replacing scan 0x%04x with key 0x%04x\n",
- rc, scancode, keycode);
-
- clear_bit(keymap[rc].keycode, dev->keybit);
-
- spin_lock_irqsave(&rc_tab->lock, flags);
- keymap[rc].keycode = keycode;
- spin_unlock_irqrestore(&rc_tab->lock, flags);
-
set_bit(keycode, dev->keybit);
return 0;