linux/drivers/media/video/bt8xx/bttv-if.c
Trent Piepho 4b10d3b626 V4L/DVB (10568): bttv: dynamically allocate device data
The bttv driver had static array of structures for up to 16 possible bttv
devices, even though few users have more than one or two.  The structures
were quite large and this resulted in a huge BSS segment.

Change the driver to allocate the bttv device data dynamically, which
changes "struct bttv bttvs[BTTV_MAX]" to "struct bttv *bttvs[BTTV_MAX]".
It would be nice to get ride of "bttvs" entirely but there are some
complications with gpio access from the audio & mpeg drivers.

To help bttvs removal along anyway, I changed the open() methods use the
video device's drvdata to get the driver data instead of looking it up in
the bttvs array.  This is also more efficient.  Some WARN_ON()s are added
in cases the device node exists by the bttv device doesn't, which I don't
think should be possible.

The gpio access functions need to check if bttvs[card] is NULL now.  Though
calling them on a non-existent card in the first place is wrong, but hard
to solve given the fundamental problems in how the gpio access code works.

This patch reduces the bss size by 66560 bytes on ia32.  Overall change is a
reduction of 66398 bytes, as the WARN_ON()s add some 198 bytes.

Signed-off-by: Trent Piepho <xyzzy@speakeasy.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2009-03-30 12:42:47 -03:00

121 lines
2.8 KiB
C

/*
bttv-if.c -- old gpio interface to other kernel modules
don't use in new code, will go away in 2.7
have a look at bttv-gpio.c instead.
bttv - Bt848 frame grabber driver
Copyright (C) 1996,97,98 Ralph Metzler (rjkm@thp.uni-koeln.de)
& Marcus Metzler (mocm@thp.uni-koeln.de)
(c) 1999-2003 Gerd Knorr <kraxel@bytesex.org>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <asm/io.h>
#include "bttvp.h"
EXPORT_SYMBOL(bttv_get_pcidev);
EXPORT_SYMBOL(bttv_gpio_enable);
EXPORT_SYMBOL(bttv_read_gpio);
EXPORT_SYMBOL(bttv_write_gpio);
/* ----------------------------------------------------------------------- */
/* Exported functions - for other modules which want to access the */
/* gpio ports (IR for example) */
/* see bttv.h for comments */
struct pci_dev* bttv_get_pcidev(unsigned int card)
{
if (card >= bttv_num)
return NULL;
if (!bttvs[card])
return NULL;
return bttvs[card]->c.pci;
}
int bttv_gpio_enable(unsigned int card, unsigned long mask, unsigned long data)
{
struct bttv *btv;
if (card >= bttv_num) {
return -EINVAL;
}
btv = bttvs[card];
if (!btv)
return -ENODEV;
gpio_inout(mask,data);
if (bttv_gpio)
bttv_gpio_tracking(btv,"extern enable");
return 0;
}
int bttv_read_gpio(unsigned int card, unsigned long *data)
{
struct bttv *btv;
if (card >= bttv_num) {
return -EINVAL;
}
btv = bttvs[card];
if (!btv)
return -ENODEV;
if(btv->shutdown) {
return -ENODEV;
}
/* prior setting BT848_GPIO_REG_INP is (probably) not needed
because we set direct input on init */
*data = gpio_read();
return 0;
}
int bttv_write_gpio(unsigned int card, unsigned long mask, unsigned long data)
{
struct bttv *btv;
if (card >= bttv_num) {
return -EINVAL;
}
btv = bttvs[card];
if (!btv)
return -ENODEV;
/* prior setting BT848_GPIO_REG_INP is (probably) not needed
because direct input is set on init */
gpio_bits(mask,data);
if (bttv_gpio)
bttv_gpio_tracking(btv,"extern write");
return 0;
}
/*
* Local variables:
* c-basic-offset: 8
* End:
*/