drm/i915: Use a macro to express the range of valid gens for reg_read
The reg_read whitelist has a gen bitmask to code the gens we're allowing
the register to be read on. Until now, it was a literal, but we can be
a bit more expressive.
To ease the review, a small test program:
$ cat bit-range.c
#include <stdio.h>
#include <stdint.h>
#define U32_C(x) x ## U
#define GENMASK(h, l) (((U32_C(1) << ((h) - (l) + 1)) - 1) << (l))
#define GEN_RANGE(l, h) GENMASK(h, l)
int main(int argc, char **argv)
{
printf("0x%08x\n", GEN_RANGE(1, 1));
printf("0x%08x\n", GEN_RANGE(1, 2));
printf("0x%08x\n", GEN_RANGE(4, 4));
printf("0x%08x\n", GEN_RANGE(4, 5));
printf("0x%08x\n", GEN_RANGE(1, 31));
printf("0x%08x\n", GEN_RANGE(4, 8));
return 0;
}
$ ./bit-range
0x00000002
0x00000006
0x00000010
0x00000030
0xfffffffe
0x000001f0
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
1 file changed