| Message ID | 1470088892-31373-1-git-send-email-robert.jarzmik@free.fr (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Robert Jarzmik <robert.jarzmik@free.fr> writes: > The commit 9bf448c66d4b ("ARM: pxa: use generic gpio operation instead of > gpio register") from Oct 17, 2011, leads to the following static checker > warning: > arch/arm/mach-pxa/spitz_pm.c:172 spitz_charger_wakeup() > warn: double left shift '!gpio_get_value(SPITZ_GPIO_KEY_INT) > << (1 << ((SPITZ_GPIO_KEY_INT) & 31))' > > As Dan reported, the value is shifted three times : > - once by gpio_get_value(), which returns either 0 or BIT(gpio) > - once by the shift operation '<<' > - a last time by GPIO_bit(gpio) which is BIT(gpio) > > Therefore the calculation lead to a chained or operator of : > - (1 << gpio) << (1 << gpio) = (2^gpio)^gpio = 2 ^ (gpio * gpio) > > It is be sheer luck the former statement works, only because each gpio > used is strictly smaller than 6, and therefore 2^(gpio^2) never > overflows a 32 bits value, and because it is used as a boolean value to > check a gpio activation. > > As the xxx_charger_wakeup() functions are used as a true/false detection > mechanism, take that opportunity to change their prototypes from integer > return value to boolean one. > > Fixes: 9bf448c66d4b ("ARM: pxa: use generic gpio operation instead of > gpio register") > Reported-by: Dan Carpenter <dan.carpenter@oracle.com> > Cc: Joe Perches <joe@perches.com> > Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr> Queued into pxa/for-next. -- Robert
diff --git a/arch/arm/mach-pxa/corgi_pm.c b/arch/arm/mach-pxa/corgi_pm.c index d9206811be9b..c71c483f410e 100644 --- a/arch/arm/mach-pxa/corgi_pm.c +++ b/arch/arm/mach-pxa/corgi_pm.c @@ -131,16 +131,11 @@ static int corgi_should_wakeup(unsigned int resume_on_alarm) return is_resume; } -static unsigned long corgi_charger_wakeup(void) +static bool corgi_charger_wakeup(void) { - unsigned long ret; - - ret = (!gpio_get_value(CORGI_GPIO_AC_IN) << GPIO_bit(CORGI_GPIO_AC_IN)) - | (!gpio_get_value(CORGI_GPIO_KEY_INT) - << GPIO_bit(CORGI_GPIO_KEY_INT)) - | (!gpio_get_value(CORGI_GPIO_WAKEUP) - << GPIO_bit(CORGI_GPIO_WAKEUP)); - return ret; + return !gpio_get_value(CORGI_GPIO_AC_IN) || + !gpio_get_value(CORGI_GPIO_KEY_INT) || + !gpio_get_value(CORGI_GPIO_WAKEUP); } unsigned long corgipm_read_devdata(int type) diff --git a/arch/arm/mach-pxa/sharpsl_pm.c b/arch/arm/mach-pxa/sharpsl_pm.c index b80eab9993c5..249b7bd5fbc4 100644 --- a/arch/arm/mach-pxa/sharpsl_pm.c +++ b/arch/arm/mach-pxa/sharpsl_pm.c @@ -744,7 +744,7 @@ static int sharpsl_off_charge_battery(void) time = RCNR; while (1) { /* Check if any wakeup event had occurred */ - if (sharpsl_pm.machinfo->charger_wakeup() != 0) + if (sharpsl_pm.machinfo->charger_wakeup()) return 0; /* Check for timeout */ if ((RCNR - time) > SHARPSL_WAIT_CO_TIME) diff --git a/arch/arm/mach-pxa/sharpsl_pm.h b/arch/arm/mach-pxa/sharpsl_pm.h index 905be6755f04..fa75b6df8134 100644 --- a/arch/arm/mach-pxa/sharpsl_pm.h +++ b/arch/arm/mach-pxa/sharpsl_pm.h @@ -34,7 +34,7 @@ struct sharpsl_charger_machinfo { #define SHARPSL_STATUS_LOCK 5 #define SHARPSL_STATUS_CHRGFULL 6 #define SHARPSL_STATUS_FATAL 7 - unsigned long (*charger_wakeup)(void); + bool (*charger_wakeup)(void); int (*should_wakeup)(unsigned int resume_on_alarm); void (*backlight_limit)(int); int (*backlight_get_status) (void); diff --git a/arch/arm/mach-pxa/spitz_pm.c b/arch/arm/mach-pxa/spitz_pm.c index ea9f9034cb54..4e64a140252e 100644 --- a/arch/arm/mach-pxa/spitz_pm.c +++ b/arch/arm/mach-pxa/spitz_pm.c @@ -165,13 +165,10 @@ static int spitz_should_wakeup(unsigned int resume_on_alarm) return is_resume; } -static unsigned long spitz_charger_wakeup(void) +static bool spitz_charger_wakeup(void) { - unsigned long ret; - ret = ((!gpio_get_value(SPITZ_GPIO_KEY_INT) - << GPIO_bit(SPITZ_GPIO_KEY_INT)) - | gpio_get_value(SPITZ_GPIO_SYNC)); - return ret; + return !gpio_get_value(SPITZ_GPIO_KEY_INT) || + gpio_get_value(SPITZ_GPIO_SYNC); } unsigned long spitzpm_read_devdata(int type)
The commit 9bf448c66d4b ("ARM: pxa: use generic gpio operation instead of gpio register") from Oct 17, 2011, leads to the following static checker warning: arch/arm/mach-pxa/spitz_pm.c:172 spitz_charger_wakeup() warn: double left shift '!gpio_get_value(SPITZ_GPIO_KEY_INT) << (1 << ((SPITZ_GPIO_KEY_INT) & 31))' As Dan reported, the value is shifted three times : - once by gpio_get_value(), which returns either 0 or BIT(gpio) - once by the shift operation '<<' - a last time by GPIO_bit(gpio) which is BIT(gpio) Therefore the calculation lead to a chained or operator of : - (1 << gpio) << (1 << gpio) = (2^gpio)^gpio = 2 ^ (gpio * gpio) It is be sheer luck the former statement works, only because each gpio used is strictly smaller than 6, and therefore 2^(gpio^2) never overflows a 32 bits value, and because it is used as a boolean value to check a gpio activation. As the xxx_charger_wakeup() functions are used as a true/false detection mechanism, take that opportunity to change their prototypes from integer return value to boolean one. Fixes: 9bf448c66d4b ("ARM: pxa: use generic gpio operation instead of gpio register") Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: Joe Perches <joe@perches.com> Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr> --- Since v1: replaced binary ORs with logical ORs after assembly comparison Since v2: changed charger_wakeup prototype to bool foo() Since v3: direct return statements in xxx_charger_wakeup() --- arch/arm/mach-pxa/corgi_pm.c | 13 ++++--------- arch/arm/mach-pxa/sharpsl_pm.c | 2 +- arch/arm/mach-pxa/sharpsl_pm.h | 2 +- arch/arm/mach-pxa/spitz_pm.c | 9 +++------ 4 files changed, 9 insertions(+), 17 deletions(-)