diff options
| author | Ben Skeggs <bskeggs@redhat.com> | 2013-01-24 12:15:45 +1000 |
|---|---|---|
| committer | Ben Skeggs <bskeggs@redhat.com> | 2013-07-01 13:44:06 +1000 |
| commit | da746d4ec9605302386bab46ea8dfdd66f94560c (patch) | |
| tree | 380aa9f84f949dafe680e6889295c9c67fa4333f | |
| parent | dceef5d87cc01358cc1434416f3272e2ddc3d97a (diff) | |
| download | linux-da746d4ec9605302386bab46ea8dfdd66f94560c.tar.gz | |
drm/nva3/clk: minor improvements to fractional N calculation
Helps us to get identical numbers to the binary driver for (at least) Kepler memory PLLs, and fixes a rounding error. Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
| -rw-r--r-- | drivers/gpu/drm/nouveau/core/subdev/clock/pllnva3.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/drivers/gpu/drm/nouveau/core/subdev/clock/pllnva3.c b/drivers/gpu/drm/nouveau/core/subdev/clock/pllnva3.c index 4497378ba1e8..2fe1f712eefa 100644 --- a/drivers/gpu/drm/nouveau/core/subdev/clock/pllnva3.c +++ b/drivers/gpu/drm/nouveau/core/subdev/clock/pllnva3.c @@ -50,8 +50,15 @@ nva3_pll_calc(struct nouveau_subdev *subdev, struct nvbios_pll *info, u32 tmp = freq * *P * M; N = tmp / info->refclk; fN = tmp % info->refclk; - if (!pfN && fN >= info->refclk / 2) - N++; + + if (!pfN) { + if (fN >= info->refclk / 2) + N++; + } else { + if (fN < info->refclk / 2) + N--; + fN = tmp - (N * info->refclk); + } if (N < info->vco1.min_n) continue; @@ -66,7 +73,8 @@ nva3_pll_calc(struct nouveau_subdev *subdev, struct nvbios_pll *info, } if (pfN) { - *pfN = (((fN << 13) / info->refclk) - 4096) & 0xffff; + *pfN = ((fN << 13) + info->refclk / 2) / info->refclk; + *pfN = (*pfN - 4096) & 0xffff; return freq; } } |