linux/sound/drivers/mpu401/mpu401.c
David Howells b11ce420c5 Annotate hardware config module parameters in sound/drivers/
When the kernel is running in secure boot mode, we lock down the kernel to
prevent userspace from modifying the running kernel image.  Whilst this
includes prohibiting access to things like /dev/mem, it must also prevent
access by means of configuring driver modules in such a way as to cause a
device to access or modify the kernel image.

To this end, annotate module_param* statements that refer to hardware
configuration and indicate for future reference what type of parameter they
specify.  The parameter parser in the core sees this information and can
skip such parameters with an error message if the kernel is locked down.
The module initialisation then runs as normal, but just sees whatever the
default values for those parameters is.

Note that we do still need to do the module initialisation because some
drivers have viable defaults set in case parameters aren't specified and
some drivers support automatic configuration (e.g. PNP or PCI) in addition
to manually coded parameters.

This patch annotates drivers in sound/drivers/.

Suggested-by: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
cc: Jaroslav Kysela <perex@perex.cz>
cc: alsa-devel@alsa-project.org
2017-04-20 12:02:32 +01:00

288 lines
7.4 KiB
C

/*
* Driver for generic MPU-401 boards (UART mode only)
* Copyright (c) by Jaroslav Kysela <perex@perex.cz>
* Copyright (c) 2004 by Castet Matthieu <castet.matthieu@free.fr>
*
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include <linux/init.h>
#include <linux/pnp.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/module.h>
#include <sound/core.h>
#include <sound/mpu401.h>
#include <sound/initval.h>
MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
MODULE_DESCRIPTION("MPU-401 UART");
MODULE_LICENSE("GPL");
static int index[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = -2}; /* exclude the first card */
static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR; /* ID for this card */
static bool enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE; /* Enable this card */
#ifdef CONFIG_PNP
static bool pnp[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 1};
#endif
static long port[SNDRV_CARDS] = SNDRV_DEFAULT_PORT; /* MPU-401 port number */
static int irq[SNDRV_CARDS] = SNDRV_DEFAULT_IRQ; /* MPU-401 IRQ */
static bool uart_enter[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 1};
module_param_array(index, int, NULL, 0444);
MODULE_PARM_DESC(index, "Index value for MPU-401 device.");
module_param_array(id, charp, NULL, 0444);
MODULE_PARM_DESC(id, "ID string for MPU-401 device.");
module_param_array(enable, bool, NULL, 0444);
MODULE_PARM_DESC(enable, "Enable MPU-401 device.");
#ifdef CONFIG_PNP
module_param_array(pnp, bool, NULL, 0444);
MODULE_PARM_DESC(pnp, "PnP detection for MPU-401 device.");
#endif
module_param_hw_array(port, long, ioport, NULL, 0444);
MODULE_PARM_DESC(port, "Port # for MPU-401 device.");
module_param_hw_array(irq, int, irq, NULL, 0444);
MODULE_PARM_DESC(irq, "IRQ # for MPU-401 device.");
module_param_array(uart_enter, bool, NULL, 0444);
MODULE_PARM_DESC(uart_enter, "Issue UART_ENTER command at open.");
static struct platform_device *platform_devices[SNDRV_CARDS];
static int pnp_registered;
static unsigned int snd_mpu401_devices;
static int snd_mpu401_create(struct device *devptr, int dev,
struct snd_card **rcard)
{
struct snd_card *card;
int err;
if (!uart_enter[dev])
snd_printk(KERN_ERR "the uart_enter option is obsolete; remove it\n");
*rcard = NULL;
err = snd_card_new(devptr, index[dev], id[dev], THIS_MODULE,
0, &card);
if (err < 0)
return err;
strcpy(card->driver, "MPU-401 UART");
strcpy(card->shortname, card->driver);
sprintf(card->longname, "%s at %#lx, ", card->shortname, port[dev]);
if (irq[dev] >= 0) {
sprintf(card->longname + strlen(card->longname), "irq %d", irq[dev]);
} else {
strcat(card->longname, "polled");
}
err = snd_mpu401_uart_new(card, 0, MPU401_HW_MPU401, port[dev], 0,
irq[dev], NULL);
if (err < 0) {
printk(KERN_ERR "MPU401 not detected at 0x%lx\n", port[dev]);
goto _err;
}
*rcard = card;
return 0;
_err:
snd_card_free(card);
return err;
}
static int snd_mpu401_probe(struct platform_device *devptr)
{
int dev = devptr->id;
int err;
struct snd_card *card;
if (port[dev] == SNDRV_AUTO_PORT) {
snd_printk(KERN_ERR "specify port\n");
return -EINVAL;
}
if (irq[dev] == SNDRV_AUTO_IRQ) {
snd_printk(KERN_ERR "specify or disable IRQ\n");
return -EINVAL;
}
err = snd_mpu401_create(&devptr->dev, dev, &card);
if (err < 0)
return err;
if ((err = snd_card_register(card)) < 0) {
snd_card_free(card);
return err;
}
platform_set_drvdata(devptr, card);
return 0;
}
static int snd_mpu401_remove(struct platform_device *devptr)
{
snd_card_free(platform_get_drvdata(devptr));
return 0;
}
#define SND_MPU401_DRIVER "snd_mpu401"
static struct platform_driver snd_mpu401_driver = {
.probe = snd_mpu401_probe,
.remove = snd_mpu401_remove,
.driver = {
.name = SND_MPU401_DRIVER,
},
};
#ifdef CONFIG_PNP
#define IO_EXTENT 2
static struct pnp_device_id snd_mpu401_pnpids[] = {
{ .id = "PNPb006" },
{ .id = "" }
};
MODULE_DEVICE_TABLE(pnp, snd_mpu401_pnpids);
static int snd_mpu401_pnp(int dev, struct pnp_dev *device,
const struct pnp_device_id *id)
{
if (!pnp_port_valid(device, 0) ||
pnp_port_flags(device, 0) & IORESOURCE_DISABLED) {
snd_printk(KERN_ERR "no PnP port\n");
return -ENODEV;
}
if (pnp_port_len(device, 0) < IO_EXTENT) {
snd_printk(KERN_ERR "PnP port length is %llu, expected %d\n",
(unsigned long long)pnp_port_len(device, 0),
IO_EXTENT);
return -ENODEV;
}
port[dev] = pnp_port_start(device, 0);
if (!pnp_irq_valid(device, 0) ||
pnp_irq_flags(device, 0) & IORESOURCE_DISABLED) {
snd_printk(KERN_WARNING "no PnP irq, using polling\n");
irq[dev] = -1;
} else {
irq[dev] = pnp_irq(device, 0);
}
return 0;
}
static int snd_mpu401_pnp_probe(struct pnp_dev *pnp_dev,
const struct pnp_device_id *id)
{
static int dev;
struct snd_card *card;
int err;
for ( ; dev < SNDRV_CARDS; ++dev) {
if (!enable[dev] || !pnp[dev])
continue;
err = snd_mpu401_pnp(dev, pnp_dev, id);
if (err < 0)
return err;
err = snd_mpu401_create(&pnp_dev->dev, dev, &card);
if (err < 0)
return err;
if ((err = snd_card_register(card)) < 0) {
snd_card_free(card);
return err;
}
pnp_set_drvdata(pnp_dev, card);
snd_mpu401_devices++;
++dev;
return 0;
}
return -ENODEV;
}
static void snd_mpu401_pnp_remove(struct pnp_dev *dev)
{
struct snd_card *card = (struct snd_card *) pnp_get_drvdata(dev);
snd_card_disconnect(card);
snd_card_free_when_closed(card);
}
static struct pnp_driver snd_mpu401_pnp_driver = {
.name = "mpu401",
.id_table = snd_mpu401_pnpids,
.probe = snd_mpu401_pnp_probe,
.remove = snd_mpu401_pnp_remove,
};
#else
static struct pnp_driver snd_mpu401_pnp_driver;
#endif
static void snd_mpu401_unregister_all(void)
{
int i;
if (pnp_registered)
pnp_unregister_driver(&snd_mpu401_pnp_driver);
for (i = 0; i < ARRAY_SIZE(platform_devices); ++i)
platform_device_unregister(platform_devices[i]);
platform_driver_unregister(&snd_mpu401_driver);
}
static int __init alsa_card_mpu401_init(void)
{
int i, err;
if ((err = platform_driver_register(&snd_mpu401_driver)) < 0)
return err;
for (i = 0; i < SNDRV_CARDS; i++) {
struct platform_device *device;
if (! enable[i])
continue;
#ifdef CONFIG_PNP
if (pnp[i])
continue;
#endif
device = platform_device_register_simple(SND_MPU401_DRIVER,
i, NULL, 0);
if (IS_ERR(device))
continue;
if (!platform_get_drvdata(device)) {
platform_device_unregister(device);
continue;
}
platform_devices[i] = device;
snd_mpu401_devices++;
}
err = pnp_register_driver(&snd_mpu401_pnp_driver);
if (!err)
pnp_registered = 1;
if (!snd_mpu401_devices) {
#ifdef MODULE
printk(KERN_ERR "MPU-401 device not found or device busy\n");
#endif
snd_mpu401_unregister_all();
return -ENODEV;
}
return 0;
}
static void __exit alsa_card_mpu401_exit(void)
{
snd_mpu401_unregister_all();
}
module_init(alsa_card_mpu401_init)
module_exit(alsa_card_mpu401_exit)