On Fri, 28 Oct 2022 21:42:30 -0700, Gwan-gyeong Mun wrote:
>
> Use REG_FIELD_PREP() and a constant value for hwm_field_scale_and_write()
R-b'ing this so that this can get merged since this compile break is
blocking drm-intel-gt-next pull request:
Reviewed-by: Ashutosh Dixit <ashutosh.dixit@xxxxxxxxx>
> If the first argument of FIELD_PREP() is not a compile-time constant value
> or unsigned long long type, this routine of the __BF_FIELD_CHECK() macro
> used internally by the FIELD_PREP() macro always returns false.
>
> BUILD_BUG_ON_MSG(__bf_cast_unsigned(_mask, _mask) > \
> __bf_cast_unsigned(_reg, ~0ull), \
> _pfx "type of reg too small for mask"); \
>
> And it returns a build error by the option among the clang
> compilation options. [-Werror,-Wtautological-constant-out-of-range-compare]
>
> Reported build error while using clang compiler:
>
> drivers/gpu/drm/i915/i915_hwmon.c:115:16: error: result of comparison of constant 18446744073709551615 with expression of type 'typeof (_Generic((field_msk), char: (unsigned char)0, unsigned char: (unsigned char)0, signed char: (unsigned char)0, unsigned short: (unsigned short)0, short: (unsigned short)0, unsigned int: (unsigned int)0, int: (unsigned int)0, unsigned long: (unsigned long)0, long: (unsigned long)0, unsigned long long: (unsigned long long)0, long long: (unsigned long long)0, default: (field_msk)))' (aka 'unsigned int') is always false [-Werror,-Wtautological-constant-out-of-range-compare]
> bits_to_set = FIELD_PREP(field_msk, nval);
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~
> ./include/linux/bitfield.h:114:3: note: expanded from macro 'FIELD_PREP'
> __BF_FIELD_CHECK(_mask, 0ULL, _val, "FIELD_PREP: "); \
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ./include/linux/bitfield.h:71:53: note: expanded from macro '__BF_FIELD_CHECK'
> BUILD_BUG_ON_MSG(__bf_cast_unsigned(_mask, _mask) > \
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~
> ./include/linux/build_bug.h:39:58: note: expanded from macro 'BUILD_BUG_ON_MSG'
> ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~
> ./include/linux/compiler_types.h:357:22: note: expanded from macro 'compiletime_assert'
> _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
> ~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ./include/linux/compiler_types.h:345:23: note: expanded from macro '_compiletime_assert'
> __compiletime_assert(condition, msg, prefix, suffix)
> ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ./include/linux/compiler_types.h:337:9: note: expanded from macro '__compiletime_assert'
> if (!(condition)) \
>
> v2: Use REG_FIELD_PREP() macro instead of FIELD_PREP() (Jani)
>
> Fixes: 99f55efb7911 ("drm/i915/hwmon: Power PL1 limit and TDP setting")
> Cc: Ashutosh Dixit <ashutosh.dixit@xxxxxxxxx>
> Cc: Anshuman Gupta <anshuman.gupta@xxxxxxxxx>
> Cc: Andi Shyti <andi.shyti@xxxxxxxxxxxxxxx>
> Cc: Jani Nikula <jani.nikula@xxxxxxxxx>
> Signed-off-by: Gwan-gyeong Mun <gwan-gyeong.mun@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/i915_hwmon.c | 12 +++---------
> 1 file changed, 3 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_hwmon.c b/drivers/gpu/drm/i915/i915_hwmon.c
> index 9e9781493025..c588a17f97e9 100644
> --- a/drivers/gpu/drm/i915/i915_hwmon.c
> +++ b/drivers/gpu/drm/i915/i915_hwmon.c
> @@ -101,21 +101,16 @@ hwm_field_read_and_scale(struct hwm_drvdata *ddat, i915_reg_t rgadr,
>
> static void
> hwm_field_scale_and_write(struct hwm_drvdata *ddat, i915_reg_t rgadr,
> - u32 field_msk, int nshift,
> - unsigned int scale_factor, long lval)
> + int nshift, unsigned int scale_factor, long lval)
> {
> u32 nval;
> - u32 bits_to_clear;
> - u32 bits_to_set;
>
> /* Computation in 64-bits to avoid overflow. Round to nearest. */
> nval = DIV_ROUND_CLOSEST_ULL((u64)lval << nshift, scale_factor);
>
> - bits_to_clear = field_msk;
> - bits_to_set = FIELD_PREP(field_msk, nval);
> -
> hwm_locked_with_pm_intel_uncore_rmw(ddat, rgadr,
> - bits_to_clear, bits_to_set);
> + PKG_PWR_LIM_1,
> + REG_FIELD_PREP(PKG_PWR_LIM_1, nval));
> }
>
> /*
> @@ -406,7 +401,6 @@ hwm_power_write(struct hwm_drvdata *ddat, u32 attr, int chan, long val)
> case hwmon_power_max:
> hwm_field_scale_and_write(ddat,
> hwmon->rg.pkg_rapl_limit,
> - PKG_PWR_LIM_1,
> hwmon->scl_shift_power,
> SF_POWER, val);
> return 0;
> --
> 2.37.1
>
