On 2026-07-02T05:57:27, Mikhail Kshevetskiy <[email protected]> wrote: > bitfield: Add non-constant field_{prep, get}() helpers > > The existing FIELD_{GET,PREP}() macros are limited to compile-time > constants. However, it is very common to prepare or extract bitfield > elements where the bitfield mask is not a compile-time constant. > > To avoid this limitation, the AT91 clock driver and several other > drivers already have their own non-const field_{prep,get}() macros. > Make them available for general use by adding them to > <linux/bitfield.h>, and improve them slightly: > 1. Avoid evaluating macro parameters more than once, > 2. Replace "ffs() - 1" by __ffs(), > 3. Support 64-bit use on 32-bit architectures, > 4. Wire field_{get,prep}() to FIELD_{GET,PREP}() when mask is > actually constant. > > This is deliberately not merged into the existing FIELD_{GET,PREP}() > macros, as people expressed the desire to keep stricter variants for > increased safety, or for performance critical paths. > > Yury: use __mask within new macros. > > Signed-off-by: Geert Uytterhoeven <[email protected]> > Acked-by: Alexandre Belloni <[email protected]> > Acked-by: Jonathan Cameron <[email protected]> > Acked-by: Crt Mori <[email protected]> > Acked-by: Nuno Sá <[email protected]> > Acked-by: Richard Genoud <[email protected]> > Reviewed-by: Andy Shevchenko <[email protected]> > Reviewed-by: Yury Norov (NVIDIA) <[email protected]> > Signed-off-by: Yury Norov (NVIDIA) <[email protected]> > Reviewed-by: David Lechner <[email protected]> > > include/linux/bitfield.h | 59 ++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 59 insertions(+)
Reviewed-by: Simon Glass <[email protected]>
