| Message ID | 20171127235155.91764-1-rlippert@google.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
On Mon, Nov 27, 2017 at 03:51:55PM -0800, Robert Lippert wrote: > Power values in the 100s of watt range can easily blow past > 32bit math limits when processing everything in microwatts. > > Use 64bit math instead to avoid these issues on common 32bit ARM > BMC platforms. > > Signed-off-by: Robert Lippert <rlippert@google.com> Applied (silently fixed two checkpatch CHECK messages) Guenter > --- > drivers/hwmon/pmbus/pmbus_core.c | 21 ++++++++++++--------- > 1 file changed, 12 insertions(+), 9 deletions(-) > > diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c > index 52a58b8b6e1b..09977440bbea 100644 > --- a/drivers/hwmon/pmbus/pmbus_core.c > +++ b/drivers/hwmon/pmbus/pmbus_core.c > @@ -21,6 +21,7 @@ > > #include <linux/debugfs.h> > #include <linux/kernel.h> > +#include <linux/math64.h> > #include <linux/module.h> > #include <linux/init.h> > #include <linux/err.h> > @@ -499,8 +500,8 @@ static long pmbus_reg2data_linear(struct pmbus_data *data, > static long pmbus_reg2data_direct(struct pmbus_data *data, > struct pmbus_sensor *sensor) > { > - long val = (s16) sensor->data; > - long m, b, R; > + s64 b, val = (s16)sensor->data; > + s32 m, R; > > m = data->info->m[sensor->class]; > b = data->info->b[sensor->class]; > @@ -528,11 +529,12 @@ static long pmbus_reg2data_direct(struct pmbus_data *data, > R--; > } > while (R < 0) { > - val = DIV_ROUND_CLOSEST(val, 10); > + val = div_s64(val + 5LL, 10L); /* round closest */ > R++; > } > > - return (val - b) / m; > + val = div_s64(val - b, m); > + return clamp_val(val, LONG_MIN, LONG_MAX); > } > > /* > @@ -656,7 +658,8 @@ static u16 pmbus_data2reg_linear(struct pmbus_data *data, > static u16 pmbus_data2reg_direct(struct pmbus_data *data, > struct pmbus_sensor *sensor, long val) > { > - long m, b, R; > + s64 b, val64 = val; > + s32 m, R; > > m = data->info->m[sensor->class]; > b = data->info->b[sensor->class]; > @@ -673,18 +676,18 @@ static u16 pmbus_data2reg_direct(struct pmbus_data *data, > R -= 3; /* Adjust R and b for data in milli-units */ > b *= 1000; > } > - val = val * m + b; > + val64 = val64 * m + b; > > while (R > 0) { > - val *= 10; > + val64 *= 10; > R--; > } > while (R < 0) { > - val = DIV_ROUND_CLOSEST(val, 10); > + val64 = div_s64(val64 + 5LL, 10L); /* round closest */ > R++; > } > > - return val; > + return (u16)clamp_val(val64, S16_MIN, S16_MAX); > } > > static u16 pmbus_data2reg_vid(struct pmbus_data *data, -- To unsubscribe from this list: send the line "unsubscribe linux-hwmon" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c index 52a58b8b6e1b..09977440bbea 100644 --- a/drivers/hwmon/pmbus/pmbus_core.c +++ b/drivers/hwmon/pmbus/pmbus_core.c @@ -21,6 +21,7 @@ #include <linux/debugfs.h> #include <linux/kernel.h> +#include <linux/math64.h> #include <linux/module.h> #include <linux/init.h> #include <linux/err.h> @@ -499,8 +500,8 @@ static long pmbus_reg2data_linear(struct pmbus_data *data, static long pmbus_reg2data_direct(struct pmbus_data *data, struct pmbus_sensor *sensor) { - long val = (s16) sensor->data; - long m, b, R; + s64 b, val = (s16) sensor->data; + s32 m, R; m = data->info->m[sensor->class]; b = data->info->b[sensor->class]; @@ -528,11 +529,12 @@ static long pmbus_reg2data_direct(struct pmbus_data *data, R--; } while (R < 0) { - val = DIV_ROUND_CLOSEST(val, 10); + val = div_s64(val + 5LL, 10L); /* round closest */ R++; } - return (val - b) / m; + val = div_s64(val - b, m); + return clamp_val(val, LONG_MIN, LONG_MAX); } /* @@ -656,7 +658,8 @@ static u16 pmbus_data2reg_linear(struct pmbus_data *data, static u16 pmbus_data2reg_direct(struct pmbus_data *data, struct pmbus_sensor *sensor, long val) { - long m, b, R; + s64 b, val64 = val; + s32 m, R; m = data->info->m[sensor->class]; b = data->info->b[sensor->class]; @@ -673,18 +676,18 @@ static u16 pmbus_data2reg_direct(struct pmbus_data *data, R -= 3; /* Adjust R and b for data in milli-units */ b *= 1000; } - val = val * m + b; + val64 = val64 * m + b; while (R > 0) { - val *= 10; + val64 *= 10; R--; } while (R < 0) { - val = DIV_ROUND_CLOSEST(val, 10); + val64 = div_s64(val64 + 5LL, 10L); /* round closest */ R++; } - return val; + return (u16) clamp_val(val64, S16_MIN, S16_MAX); } static u16 pmbus_data2reg_vid(struct pmbus_data *data,
Power values in the 100s of watt range can easily blow past 32bit math limits when processing everything in microwatts. Use 64bit math instead to avoid these issues on common 32bit ARM BMC platforms. Signed-off-by: Robert Lippert <rlippert@google.com> --- drivers/hwmon/pmbus/pmbus_core.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-)