drm/i915/skl: Factor out computing the DPLL paramaters from the dividers

This part doesn't depend on how we compute the DPLL dividers (p and
p0/p1/p2) and can be reused even if we change the algorithm to do so.
(something that is planned for a followup patch)

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index c547f03..a8d3976 100644 (file)
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -1115,6 +1115,75 @@ struct skl_wrpll_params {
        uint32_t        central_freq;
 };
 
+static void skl_wrpll_params_populate(struct skl_wrpll_params *params,
+                                     uint64_t afe_clock,
+                                     uint64_t central_freq,
+                                     uint32_t p0, uint32_t p1, uint32_t p2)
+{
+       uint64_t dco_freq;
+
+       params->central_freq = central_freq;
+
+       switch (central_freq) {
+       case 9600000000ULL:
+               params->central_freq = 0;
+               break;
+       case 9000000000ULL:
+               params->central_freq = 1;
+               break;
+       case 8400000000ULL:
+               params->central_freq = 3;
+       }
+
+       switch (p0) {
+       case 1:
+               params->pdiv = 0;
+               break;
+       case 2:
+               params->pdiv = 1;
+               break;
+       case 3:
+               params->pdiv = 2;
+               break;
+       case 7:
+               params->pdiv = 4;
+               break;
+       default:
+               WARN(1, "Incorrect PDiv\n");
+       }
+
+       switch (p2) {
+       case 5:
+               params->kdiv = 0;
+               break;
+       case 2:
+               params->kdiv = 1;
+               break;
+       case 3:
+               params->kdiv = 2;
+               break;
+       case 1:
+               params->kdiv = 3;
+               break;
+       default:
+               WARN(1, "Incorrect KDiv\n");
+       }
+
+       params->qdiv_ratio = p1;
+       params->qdiv_mode = (params->qdiv_ratio == 1) ? 0 : 1;
+
+       dco_freq = p0 * p1 * p2 * afe_clock;
+
+       /*
+        * Intermediate values are in Hz.
+        * Divide by MHz to match bsepc
+        */
+       params->dco_integer = div_u64(dco_freq, (24 * MHz(1)));
+       params->dco_fraction =
+               div_u64(((div_u64(dco_freq, 24) -
+                         params->dco_integer * MHz(1)) * 0x8000), MHz(1));
+}
+
 static bool
 skl_ddi_calculate_wrpll(int clock /* in Hz */,
                        struct skl_wrpll_params *wrpll_params)
@@ -1134,7 +1203,6 @@ skl_ddi_calculate_wrpll(int clock /* in Hz */,
        uint32_t dco_central_freq_deviation[3];
        uint32_t i, P1, k, dco_count;
        bool retry_with_odd = false;
-       uint64_t dco_freq;
 
        /* Determine P0, P1 or P2 */
        for (dco_count = 0; dco_count < 3; dco_count++) {
@@ -1197,69 +1265,12 @@ found:
                 "No valid parameters found for pixel clock: %dHz\n", clock))
                return false;
 
-       wrpll_params->central_freq = dco_central_freq[min_dco_index];
-
-       switch (dco_central_freq[min_dco_index]) {
-       case 9600000000ULL:
-               wrpll_params->central_freq = 0;
-               break;
-       case 9000000000ULL:
-               wrpll_params->central_freq = 1;
-               break;
-       case 8400000000ULL:
-               wrpll_params->central_freq = 3;
-       }
-
-       switch (candidate_p0[min_dco_index]) {
-       case 1:
-               wrpll_params->pdiv = 0;
-               break;
-       case 2:
-               wrpll_params->pdiv = 1;
-               break;
-       case 3:
-               wrpll_params->pdiv = 2;
-               break;
-       case 7:
-               wrpll_params->pdiv = 4;
-               break;
-       default:
-               WARN(1, "Incorrect PDiv\n");
-       }
-
-       switch (candidate_p2[min_dco_index]) {
-       case 5:
-               wrpll_params->kdiv = 0;
-               break;
-       case 2:
-               wrpll_params->kdiv = 1;
-               break;
-       case 3:
-               wrpll_params->kdiv = 2;
-               break;
-       case 1:
-               wrpll_params->kdiv = 3;
-               break;
-       default:
-               WARN(1, "Incorrect KDiv\n");
-       }
-
-       wrpll_params->qdiv_ratio = candidate_p1[min_dco_index];
-       wrpll_params->qdiv_mode =
-               (wrpll_params->qdiv_ratio == 1) ? 0 : 1;
-
-       dco_freq = candidate_p0[min_dco_index] *
-               candidate_p1[min_dco_index] *
-               candidate_p2[min_dco_index] * afe_clock;
-
-       /*
-        * Intermediate values are in Hz.
-        * Divide by MHz to match bsepc
-        */
-       wrpll_params->dco_integer = div_u64(dco_freq, (24 * MHz(1)));
-       wrpll_params->dco_fraction =
-               div_u64(((div_u64(dco_freq, 24) -
-                         wrpll_params->dco_integer * MHz(1)) * 0x8000), MHz(1));
+       skl_wrpll_params_populate(wrpll_params,
+                                 afe_clock,
+                                 dco_central_freq[min_dco_index],
+                                 candidate_p0[min_dco_index],
+                                 candidate_p1[min_dco_index],
+                                 candidate_p2[min_dco_index]);
 
        return true;
 }