From 6b4bf1c4952a65fae6b4043054b146642f031f19 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ville=20Syrj=C3=A4l=C3=A4?= Date: Fri, 27 Sep 2013 16:54:19 +0300 Subject: [PATCH] drm/i915: Rewrite vlv_find_best_dpll() MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Rewrite vlv_find_best_dpll() to use intel_clock_t rather than an army of local variables. Also extract the code to calculate the derived values into vlv_clock(). v2: Split up the earlier fixes, extract vlv_clock() v3: Initialize best_clock Signed-off-by: Ville Syrjälä Reviewed-by: Mika Kuoppala Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/intel_display.c | 74 ++++++++++++++++-------------------- 1 file changed, 33 insertions(+), 41 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 789e6ab..d984b10 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -335,6 +335,14 @@ static const intel_limit_t intel_limits_vlv_hdmi = { .p2_slow = 2, .p2_fast = 20 }, }; +static void vlv_clock(int refclk, intel_clock_t *clock) +{ + clock->m = clock->m1 * clock->m2; + clock->p = clock->p1 * clock->p2; + clock->vco = refclk * clock->m / clock->n; + clock->dot = clock->vco / clock->p; +} + /** * Returns whether any output on the specified pipe is of the specified type */ @@ -669,66 +677,50 @@ vlv_find_best_dpll(const intel_limit_t *limit, struct drm_crtc *crtc, int target, int refclk, intel_clock_t *match_clock, intel_clock_t *best_clock) { - u32 p1, p2, m1, m2, vco, bestn, bestm1, bestm2, bestp1, bestp2; - u32 m, n, fastclk; - u32 updrate, minupdate, p; + intel_clock_t clock; + u32 minupdate = 19200; unsigned int bestppm = 1000000; - int dotclk, flag; - flag = 0; - dotclk = target * 1000; - fastclk = dotclk / (2*100); - updrate = 0; - minupdate = 19200; - n = p = p1 = p2 = m = m1 = m2 = vco = bestn = 0; - bestm1 = bestm2 = bestp1 = bestp2 = 0; + target *= 5; /* fast clock */ + + memset(best_clock, 0, sizeof(*best_clock)); /* based on hardware requirement, prefer smaller n to precision */ - for (n = limit->n.min; n <= ((refclk) / minupdate); n++) { - updrate = refclk / n; - for (p1 = limit->p1.max; p1 > limit->p1.min; p1--) { - for (p2 = limit->p2.p2_fast+1; p2 > 0; p2--) { - if (p2 > 10) - p2 = p2 - 1; - p = p1 * p2; + for (clock.n = limit->n.min; clock.n <= ((refclk) / minupdate); clock.n++) { + for (clock.p1 = limit->p1.max; clock.p1 > limit->p1.min; clock.p1--) { + for (clock.p2 = limit->p2.p2_fast+1; clock.p2 > 0; clock.p2--) { + if (clock.p2 > 10) + clock.p2--; + clock.p = clock.p1 * clock.p2; /* based on hardware requirement, prefer bigger m1,m2 values */ - for (m1 = limit->m1.min; m1 <= limit->m1.max; m1++) { + for (clock.m1 = limit->m1.min; clock.m1 <= limit->m1.max; clock.m1++) { unsigned int ppm, diff; - m2 = DIV_ROUND_CLOSEST(fastclk * p * n, refclk * m1); - m = m1 * m2; - vco = updrate * m; + clock.m2 = DIV_ROUND_CLOSEST(target * clock.p * clock.n, + refclk * clock.m1); + + vlv_clock(refclk, &clock); - if (vco < limit->vco.min || vco >= limit->vco.max) + if (clock.vco < limit->vco.min || + clock.vco >= limit->vco.max) continue; - diff = abs(vco / p - fastclk); - ppm = div_u64(1000000ULL * diff, fastclk); - if (ppm < 100 && ((p1 * p2) > (bestp1 * bestp2))) { + diff = abs(clock.dot - target); + ppm = div_u64(1000000ULL * diff, target); + + if (ppm < 100 && clock.p > best_clock->p) { bestppm = 0; - flag = 1; + *best_clock = clock; } + if (bestppm >= 10 && ppm < bestppm - 10) { bestppm = ppm; - flag = 1; - } - if (flag) { - bestn = n; - bestm1 = m1; - bestm2 = m2; - bestp1 = p1; - bestp2 = p2; - flag = 0; + *best_clock = clock; } } } } } - best_clock->n = bestn; - best_clock->m1 = bestm1; - best_clock->m2 = bestm2; - best_clock->p1 = bestp1; - best_clock->p2 = bestp2; return true; } -- 2.7.4