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watchdog: f71808e_wdt: do stricter parameter validation

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We check the f71862fg_pin module parameter every time a watchdog device
for the f71862fg is opened, but the parameter can't change at runtime.

If we move the check to the start of init:

  - We catch userspace passing invalid, but unused, values
  - We check the condition only once
  - We simplify the code

Do so.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20200611191750.28096-6-a.fatoum@pengutronix.de
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
This commit is contained in:
Ahmad Fatoum 2020-06-11 21:17:46 +02:00 committed by Wim Van Sebroeck
parent 4f39d57584
commit 5edc8c6873
1 changed files with 12 additions and 25 deletions
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37
drivers/watchdog/f71808e_wdt.c
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@ -306,27 +306,6 @@ exit_unlock:
return err;
}
static int f71862fg_pin_configure(unsigned short ioaddr)
{
/* When ioaddr is non-zero the calling function has to take care of
mutex handling and superio preparation! */
if (f71862fg_pin == 63) {
if (ioaddr) {
/* SPI must be disabled first to use this pin! */
superio_clear_bit(ioaddr, SIO_REG_ROM_ADDR_SEL, 6);
superio_set_bit(ioaddr, SIO_REG_MFUNCT3, 4);
}
} else if (f71862fg_pin == 56) {
if (ioaddr)
superio_set_bit(ioaddr, SIO_REG_MFUNCT1, 1);
} else {
pr_err("Invalid argument f71862fg_pin=%d\n", f71862fg_pin);
return -EINVAL;
}
return 0;
}
static int watchdog_start(void)
{
int err;
@ -352,9 +331,13 @@ static int watchdog_start(void)
break;
case f71862fg:
err = f71862fg_pin_configure(watchdog.sioaddr);
if (err)
goto exit_superio;
if (f71862fg_pin == 63) {
/* SPI must be disabled first to use this pin! */
superio_clear_bit(watchdog.sioaddr, SIO_REG_ROM_ADDR_SEL, 6);
superio_set_bit(watchdog.sioaddr, SIO_REG_MFUNCT3, 4);
} else if (f71862fg_pin == 56) {
superio_set_bit(watchdog.sioaddr, SIO_REG_MFUNCT1, 1);
}
break;
case f71868:
@ -810,7 +793,6 @@ static int __init f71808e_find(int sioaddr)
break;
case SIO_F71862_ID:
watchdog.type = f71862fg;
err = f71862fg_pin_configure(0); /* validate module parameter */
break;
case SIO_F71868_ID:
watchdog.type = f71868;
@ -859,6 +841,11 @@ static int __init f71808e_init(void)
int err = -ENODEV;
int i;
if (f71862fg_pin != 63 && f71862fg_pin != 56) {
pr_err("Invalid argument f71862fg_pin=%d\n", f71862fg_pin);
return -EINVAL;
}
for (i = 0; i < ARRAY_SIZE(addrs); i++) {
err = f71808e_find(addrs[i]);
if (err == 0)