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V4L/DVB (13542): ir-keytable: Allow dynamic table change

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Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Mauro Carvalho Chehab 2009-12-04 17:17:47 -03:00
parent 92fda216b4
commit e97f467796
1 changed files with 200 additions and 13 deletions
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213
drivers/media/common/ir-keytable.c
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@ -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 @@ static int ir_getkeycode(struct input_dev *dev,
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 @@ static int ir_setkeycode(struct input_dev *dev,
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;