ville.syrj...@linux.intel.com writes:
> From: Ville Syrjälä <ville.syrj...@linux.intel.com>
>
> 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()
>
> Signed-off-by: Ville Syrjälä <ville.syrj...@linux.intel.com>
> ---
> drivers/gpu/drm/i915/intel_display.c | 72
> ++++++++++++++++--------------------
> 1 file changed, 31 insertions(+), 41 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_display.c
> b/drivers/gpu/drm/i915/intel_display.c
> index f646fea..c5f0794 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -438,6 +438,14 @@ static void i9xx_clock(int refclk, intel_clock_t *clock)
> clock->dot = clock->vco / clock->p;
> }
>
> +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
> */
> @@ -670,66 +678,48 @@ 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 */
>
> /* 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 */
Is this comment valid as we seem to start from m1.min?
> - 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);
>
> - if (vco < limit->vco.min || vco >=
> limit->vco.max)
> + vlv_clock(refclk, &clock);
> +
> + if (clock.vco < limit->vco.min ||
> + clock.vco >= limit->vco.max)
> continue;
Can intel_PLL_is_valid() used here instead of just checking the vco?
>
> - 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;
> }
> --
> 1.8.1.5
>
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