[Intel-gfx] [PATCH] drm/i915: Compute WR PLL dividers dynamically
Damien Lespiau
damien.lespiau at intel.com
Fri May 10 15:01:51 CEST 2013
Up to now, we were using a static table to match the clock frequency
with a (r2,n2,p) triplet. Despite this table being big, it's by no mean
comprehensive and we had to fall back to the closest frequency when the
requested TMDS clock wasn't in the table.
This patch computes (r2,n2,p) dynamically and get rid of The Big Table.
v2: Replace the floating point constant 1e6 by 1000000
Bugzilla: http://bugs.freedesktop.org/show_bug.cgi?id=58497
Signed-off-by: Damien Lespiau <damien.lespiau at intel.com>
---
drivers/gpu/drm/i915/intel_ddi.c | 617 ++++++++++++++-------------------------
1 file changed, 214 insertions(+), 403 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index 1468932..5c35386 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -281,392 +281,6 @@ void hsw_fdi_link_train(struct drm_crtc *crtc)
DRM_ERROR("FDI link training failed!\n");
}
-/* WRPLL clock dividers */
-struct wrpll_tmds_clock {
- u32 clock;
- u16 p; /* Post divider */
- u16 n2; /* Feedback divider */
- u16 r2; /* Reference divider */
-};
-
-/* Table of matching values for WRPLL clocks programming for each frequency.
- * The code assumes this table is sorted. */
-static const struct wrpll_tmds_clock wrpll_tmds_clock_table[] = {
- {19750, 38, 25, 18},
- {20000, 48, 32, 18},
- {21000, 36, 21, 15},
- {21912, 42, 29, 17},
- {22000, 36, 22, 15},
- {23000, 36, 23, 15},
- {23500, 40, 40, 23},
- {23750, 26, 16, 14},
- {24000, 36, 24, 15},
- {25000, 36, 25, 15},
- {25175, 26, 40, 33},
- {25200, 30, 21, 15},
- {26000, 36, 26, 15},
- {27000, 30, 21, 14},
- {27027, 18, 100, 111},
- {27500, 30, 29, 19},
- {28000, 34, 30, 17},
- {28320, 26, 30, 22},
- {28322, 32, 42, 25},
- {28750, 24, 23, 18},
- {29000, 30, 29, 18},
- {29750, 32, 30, 17},
- {30000, 30, 25, 15},
- {30750, 30, 41, 24},
- {31000, 30, 31, 18},
- {31500, 30, 28, 16},
- {32000, 30, 32, 18},
- {32500, 28, 32, 19},
- {33000, 24, 22, 15},
- {34000, 28, 30, 17},
- {35000, 26, 32, 19},
- {35500, 24, 30, 19},
- {36000, 26, 26, 15},
- {36750, 26, 46, 26},
- {37000, 24, 23, 14},
- {37762, 22, 40, 26},
- {37800, 20, 21, 15},
- {38000, 24, 27, 16},
- {38250, 24, 34, 20},
- {39000, 24, 26, 15},
- {40000, 24, 32, 18},
- {40500, 20, 21, 14},
- {40541, 22, 147, 89},
- {40750, 18, 19, 14},
- {41000, 16, 17, 14},
- {41500, 22, 44, 26},
- {41540, 22, 44, 26},
- {42000, 18, 21, 15},
- {42500, 22, 45, 26},
- {43000, 20, 43, 27},
- {43163, 20, 24, 15},
- {44000, 18, 22, 15},
- {44900, 20, 108, 65},
- {45000, 20, 25, 15},
- {45250, 20, 52, 31},
- {46000, 18, 23, 15},
- {46750, 20, 45, 26},
- {47000, 20, 40, 23},
- {48000, 18, 24, 15},
- {49000, 18, 49, 30},
- {49500, 16, 22, 15},
- {50000, 18, 25, 15},
- {50500, 18, 32, 19},
- {51000, 18, 34, 20},
- {52000, 18, 26, 15},
- {52406, 14, 34, 25},
- {53000, 16, 22, 14},
- {54000, 16, 24, 15},
- {54054, 16, 173, 108},
- {54500, 14, 24, 17},
- {55000, 12, 22, 18},
- {56000, 14, 45, 31},
- {56250, 16, 25, 15},
- {56750, 14, 25, 17},
- {57000, 16, 27, 16},
- {58000, 16, 43, 25},
- {58250, 16, 38, 22},
- {58750, 16, 40, 23},
- {59000, 14, 26, 17},
- {59341, 14, 40, 26},
- {59400, 16, 44, 25},
- {60000, 16, 32, 18},
- {60500, 12, 39, 29},
- {61000, 14, 49, 31},
- {62000, 14, 37, 23},
- {62250, 14, 42, 26},
- {63000, 12, 21, 15},
- {63500, 14, 28, 17},
- {64000, 12, 27, 19},
- {65000, 14, 32, 19},
- {65250, 12, 29, 20},
- {65500, 12, 32, 22},
- {66000, 12, 22, 15},
- {66667, 14, 38, 22},
- {66750, 10, 21, 17},
- {67000, 14, 33, 19},
- {67750, 14, 58, 33},
- {68000, 14, 30, 17},
- {68179, 14, 46, 26},
- {68250, 14, 46, 26},
- {69000, 12, 23, 15},
- {70000, 12, 28, 18},
- {71000, 12, 30, 19},
- {72000, 12, 24, 15},
- {73000, 10, 23, 17},
- {74000, 12, 23, 14},
- {74176, 8, 100, 91},
- {74250, 10, 22, 16},
- {74481, 12, 43, 26},
- {74500, 10, 29, 21},
- {75000, 12, 25, 15},
- {75250, 10, 39, 28},
- {76000, 12, 27, 16},
- {77000, 12, 53, 31},
- {78000, 12, 26, 15},
- {78750, 12, 28, 16},
- {79000, 10, 38, 26},
- {79500, 10, 28, 19},
- {80000, 12, 32, 18},
- {81000, 10, 21, 14},
- {81081, 6, 100, 111},
- {81624, 8, 29, 24},
- {82000, 8, 17, 14},
- {83000, 10, 40, 26},
- {83950, 10, 28, 18},
- {84000, 10, 28, 18},
- {84750, 6, 16, 17},
- {85000, 6, 17, 18},
- {85250, 10, 30, 19},
- {85750, 10, 27, 17},
- {86000, 10, 43, 27},
- {87000, 10, 29, 18},
- {88000, 10, 44, 27},
- {88500, 10, 41, 25},
- {89000, 10, 28, 17},
- {89012, 6, 90, 91},
- {89100, 10, 33, 20},
- {90000, 10, 25, 15},
- {91000, 10, 32, 19},
- {92000, 10, 46, 27},
- {93000, 10, 31, 18},
- {94000, 10, 40, 23},
- {94500, 10, 28, 16},
- {95000, 10, 44, 25},
- {95654, 10, 39, 22},
- {95750, 10, 39, 22},
- {96000, 10, 32, 18},
- {97000, 8, 23, 16},
- {97750, 8, 42, 29},
- {98000, 8, 45, 31},
- {99000, 8, 22, 15},
- {99750, 8, 34, 23},
- {100000, 6, 20, 18},
- {100500, 6, 19, 17},
- {101000, 6, 37, 33},
- {101250, 8, 21, 14},
- {102000, 6, 17, 15},
- {102250, 6, 25, 22},
- {103000, 8, 29, 19},
- {104000, 8, 37, 24},
- {105000, 8, 28, 18},
- {106000, 8, 22, 14},
- {107000, 8, 46, 29},
- {107214, 8, 27, 17},
- {108000, 8, 24, 15},
- {108108, 8, 173, 108},
- {109000, 6, 23, 19},
- {110000, 6, 22, 18},
- {110013, 6, 22, 18},
- {110250, 8, 49, 30},
- {110500, 8, 36, 22},
- {111000, 8, 23, 14},
- {111264, 8, 150, 91},
- {111375, 8, 33, 20},
- {112000, 8, 63, 38},
- {112500, 8, 25, 15},
- {113100, 8, 57, 34},
- {113309, 8, 42, 25},
- {114000, 8, 27, 16},
- {115000, 6, 23, 18},
- {116000, 8, 43, 25},
- {117000, 8, 26, 15},
- {117500, 8, 40, 23},
- {118000, 6, 38, 29},
- {119000, 8, 30, 17},
- {119500, 8, 46, 26},
- {119651, 8, 39, 22},
- {120000, 8, 32, 18},
- {121000, 6, 39, 29},
- {121250, 6, 31, 23},
- {121750, 6, 23, 17},
- {122000, 6, 42, 31},
- {122614, 6, 30, 22},
- {123000, 6, 41, 30},
- {123379, 6, 37, 27},
- {124000, 6, 51, 37},
- {125000, 6, 25, 18},
- {125250, 4, 13, 14},
- {125750, 4, 27, 29},
- {126000, 6, 21, 15},
- {127000, 6, 24, 17},
- {127250, 6, 41, 29},
- {128000, 6, 27, 19},
- {129000, 6, 43, 30},
- {129859, 4, 25, 26},
- {130000, 6, 26, 18},
- {130250, 6, 42, 29},
- {131000, 6, 32, 22},
- {131500, 6, 38, 26},
- {131850, 6, 41, 28},
- {132000, 6, 22, 15},
- {132750, 6, 28, 19},
- {133000, 6, 34, 23},
- {133330, 6, 37, 25},
- {134000, 6, 61, 41},
- {135000, 6, 21, 14},
- {135250, 6, 167, 111},
- {136000, 6, 62, 41},
- {137000, 6, 35, 23},
- {138000, 6, 23, 15},
- {138500, 6, 40, 26},
- {138750, 6, 37, 24},
- {139000, 6, 34, 22},
- {139050, 6, 34, 22},
- {139054, 6, 34, 22},
- {140000, 6, 28, 18},
- {141000, 6, 36, 23},
- {141500, 6, 22, 14},
- {142000, 6, 30, 19},
- {143000, 6, 27, 17},
- {143472, 4, 17, 16},
- {144000, 6, 24, 15},
- {145000, 6, 29, 18},
- {146000, 6, 47, 29},
- {146250, 6, 26, 16},
- {147000, 6, 49, 30},
- {147891, 6, 23, 14},
- {148000, 6, 23, 14},
- {148250, 6, 28, 17},
- {148352, 4, 100, 91},
- {148500, 6, 33, 20},
- {149000, 6, 48, 29},
- {150000, 6, 25, 15},
- {151000, 4, 19, 17},
- {152000, 6, 27, 16},
- {152280, 6, 44, 26},
- {153000, 6, 34, 20},
- {154000, 6, 53, 31},
- {155000, 6, 31, 18},
- {155250, 6, 50, 29},
- {155750, 6, 45, 26},
- {156000, 6, 26, 15},
- {157000, 6, 61, 35},
- {157500, 6, 28, 16},
- {158000, 6, 65, 37},
- {158250, 6, 44, 25},
- {159000, 6, 53, 30},
- {159500, 6, 39, 22},
- {160000, 6, 32, 18},
- {161000, 4, 31, 26},
- {162000, 4, 18, 15},
- {162162, 4, 131, 109},
- {162500, 4, 53, 44},
- {163000, 4, 29, 24},
- {164000, 4, 17, 14},
- {165000, 4, 22, 18},
- {166000, 4, 32, 26},
- {167000, 4, 26, 21},
- {168000, 4, 46, 37},
- {169000, 4, 104, 83},
- {169128, 4, 64, 51},
- {169500, 4, 39, 31},
- {170000, 4, 34, 27},
- {171000, 4, 19, 15},
- {172000, 4, 51, 40},
- {172750, 4, 32, 25},
- {172800, 4, 32, 25},
- {173000, 4, 41, 32},
- {174000, 4, 49, 38},
- {174787, 4, 22, 17},
- {175000, 4, 35, 27},
- {176000, 4, 30, 23},
- {177000, 4, 38, 29},
- {178000, 4, 29, 22},
- {178500, 4, 37, 28},
- {179000, 4, 53, 40},
- {179500, 4, 73, 55},
- {180000, 4, 20, 15},
- {181000, 4, 55, 41},
- {182000, 4, 31, 23},
- {183000, 4, 42, 31},
- {184000, 4, 30, 22},
- {184750, 4, 26, 19},
- {185000, 4, 37, 27},
- {186000, 4, 51, 37},
- {187000, 4, 36, 26},
- {188000, 4, 32, 23},
- {189000, 4, 21, 15},
- {190000, 4, 38, 27},
- {190960, 4, 41, 29},
- {191000, 4, 41, 29},
- {192000, 4, 27, 19},
- {192250, 4, 37, 26},
- {193000, 4, 20, 14},
- {193250, 4, 53, 37},
- {194000, 4, 23, 16},
- {194208, 4, 23, 16},
- {195000, 4, 26, 18},
- {196000, 4, 45, 31},
- {197000, 4, 35, 24},
- {197750, 4, 41, 28},
- {198000, 4, 22, 15},
- {198500, 4, 25, 17},
- {199000, 4, 28, 19},
- {200000, 4, 37, 25},
- {201000, 4, 61, 41},
- {202000, 4, 112, 75},
- {202500, 4, 21, 14},
- {203000, 4, 146, 97},
- {204000, 4, 62, 41},
- {204750, 4, 44, 29},
- {205000, 4, 38, 25},
- {206000, 4, 29, 19},
- {207000, 4, 23, 15},
- {207500, 4, 40, 26},
- {208000, 4, 37, 24},
- {208900, 4, 48, 31},
- {209000, 4, 48, 31},
- {209250, 4, 31, 20},
- {210000, 4, 28, 18},
- {211000, 4, 25, 16},
- {212000, 4, 22, 14},
- {213000, 4, 30, 19},
- {213750, 4, 38, 24},
- {214000, 4, 46, 29},
- {214750, 4, 35, 22},
- {215000, 4, 43, 27},
- {216000, 4, 24, 15},
- {217000, 4, 37, 23},
- {218000, 4, 42, 26},
- {218250, 4, 42, 26},
- {218750, 4, 34, 21},
- {219000, 4, 47, 29},
- {220000, 4, 44, 27},
- {220640, 4, 49, 30},
- {220750, 4, 36, 22},
- {221000, 4, 36, 22},
- {222000, 4, 23, 14},
- {222525, 4, 28, 17},
- {222750, 4, 33, 20},
- {227000, 4, 37, 22},
- {230250, 4, 29, 17},
- {233500, 4, 38, 22},
- {235000, 4, 40, 23},
- {238000, 4, 30, 17},
- {241500, 2, 17, 19},
- {245250, 2, 20, 22},
- {247750, 2, 22, 24},
- {253250, 2, 15, 16},
- {256250, 2, 18, 19},
- {262500, 2, 31, 32},
- {267250, 2, 66, 67},
- {268500, 2, 94, 95},
- {270000, 2, 14, 14},
- {272500, 2, 77, 76},
- {273750, 2, 57, 56},
- {280750, 2, 24, 23},
- {281250, 2, 23, 22},
- {286000, 2, 17, 16},
- {291750, 2, 26, 24},
- {296703, 2, 56, 51},
- {297000, 2, 22, 20},
- {298000, 2, 21, 19},
-};
-
static void intel_ddi_mode_set(struct drm_encoder *encoder,
struct drm_display_mode *mode,
struct drm_display_mode *adjusted_mode)
@@ -790,27 +404,224 @@ void intel_ddi_put_crtc_pll(struct drm_crtc *crtc)
intel_crtc->ddi_pll_sel = PORT_CLK_SEL_NONE;
}
-static void intel_ddi_calculate_wrpll(int clock, int *p, int *n2, int *r2)
+#define LC_FREQ 2700
+#define LC_FREQ_2K (LC_FREQ * 2000)
+
+#define P_MIN 2
+#define P_MAX 64
+#define P_INC 2
+
+/* Constraints for PLL good behavior */
+#define REF_MIN 48
+#define REF_MAX 400
+#define VCO_MIN 2400
+#define VCO_MAX 4800
+
+#define ABS_DIFF(a, b) ((a > b) ? (a - b) : (b - a))
+
+struct wrpll_rnp {
+ unsigned p, n2, r2;
+};
+
+static unsigned wrpll_get_budget_for_freq(int clock)
+{
+ unsigned budget;
+
+ switch (clock) {
+ case 25175000:
+ case 25200000:
+ case 27000000:
+ case 27027000:
+ case 37762500:
+ case 37800000:
+ case 40500000:
+ case 40541000:
+ case 54000000:
+ case 54054000:
+ case 59341000:
+ case 59400000:
+ case 72000000:
+ case 74176000:
+ case 74250000:
+ case 81000000:
+ case 81081000:
+ case 89012000:
+ case 89100000:
+ case 108000000:
+ case 108108000:
+ case 111264000:
+ case 111375000:
+ case 148352000:
+ case 148500000:
+ case 162000000:
+ case 162162000:
+ case 222525000:
+ case 222750000:
+ case 296703000:
+ case 297000000:
+ budget = 0;
+ break;
+ case 233500000:
+ case 245250000:
+ case 247750000:
+ case 253250000:
+ case 298000000:
+ budget = 1500;
+ break;
+ case 169128000:
+ case 169500000:
+ case 179500000:
+ case 202000000:
+ budget = 2000;
+ break;
+ case 256250000:
+ case 262500000:
+ case 270000000:
+ case 272500000:
+ case 273750000:
+ case 280750000:
+ case 281250000:
+ case 286000000:
+ case 291750000:
+ budget = 4000;
+ break;
+ case 267250000:
+ case 268500000:
+ budget = 5000;
+ break;
+ default:
+ budget = 1000;
+ break;
+ }
+
+ return budget;
+}
+
+static void wrpll_update_rnp(uint64_t freq2k, unsigned budget,
+ unsigned r2, unsigned n2, unsigned p,
+ struct wrpll_rnp *best)
{
- u32 i;
+ uint64_t a, b, c, d, diff, diff_best;
- for (i = 0; i < ARRAY_SIZE(wrpll_tmds_clock_table); i++)
- if (clock <= wrpll_tmds_clock_table[i].clock)
- break;
+ /* No best (r,n,p) yet */
+ if (best->p == 0) {
+ best->p = p;
+ best->n2 = n2;
+ best->r2 = r2;
+ return;
+ }
+
+ /*
+ * Output clock is (LC_FREQ_2K / 2000) * N / (P * R), which compares to
+ * freq2k.
+ *
+ * delta = 1e6 *
+ * abs(freq2k - (LC_FREQ_2K * n2/(p * r2))) /
+ * freq2k;
+ *
+ * and we would like delta <= budget.
+ *
+ * If the discrepancy is above the PPM-based budget, always prefer to
+ * improve upon the previous solution. However, if you're within the
+ * budget, try to maximize Ref * VCO, that is N / (P * R^2).
+ */
+ a = freq2k * budget * p * r2;
+ b = freq2k * budget * best->p * best->r2;
+ diff = ABS_DIFF((freq2k * p * r2), (LC_FREQ_2K * n2));
+ diff_best = ABS_DIFF((freq2k * best->p * best->r2),
+ (LC_FREQ_2K * best->n2));
+ c = 1000000 * diff;
+ d = 1000000 * diff_best;
+
+ if (a < c && b < d) {
+ /* If both are above the budget, pick the closer */
+ if (best->p * best->r2 * diff < p * r2 * diff_best) {
+ best->p = p;
+ best->n2 = n2;
+ best->r2 = r2;
+ }
+ } else if (a >= c && b < d) {
+ /* If A is below the threshold but B is above it? Update. */
+ best->p = p;
+ best->n2 = n2;
+ best->r2 = r2;
+ } else if (a >= c && b >= d) {
+ /* Both are below the limit, so pick the higher n2/(r2*r2) */
+ if (n2 * best->r2 * best->r2 > best->n2 * r2 * r2) {
+ best->p = p;
+ best->n2 = n2;
+ best->r2 = r2;
+ }
+ }
+ /* Otherwise a < c && b >= d, do nothing */
+}
+
+static void
+intel_ddi_calculate_wrpll(int clock /* in Hz */,
+ unsigned *r2_out, unsigned *n2_out, unsigned *p_out)
+{
+ uint64_t freq2k;
+ unsigned p, n2, r2;
+ struct wrpll_rnp best = { 0, 0, 0 };
+ unsigned budget;
- if (i == ARRAY_SIZE(wrpll_tmds_clock_table))
- i--;
+ freq2k = clock / 100;
- *p = wrpll_tmds_clock_table[i].p;
- *n2 = wrpll_tmds_clock_table[i].n2;
- *r2 = wrpll_tmds_clock_table[i].r2;
+ budget = wrpll_get_budget_for_freq(clock);
+
+ /* Special case handling for 540 pixel clock: bypass WR PLL entirely
+ * and directly pass the LC PLL to it. */
+ if (freq2k == 5400000) {
+ *n2_out = 2;
+ *p_out = 1;
+ *r2_out = 2;
+ return;
+ }
+
+ /*
+ * Ref = LC_FREQ / R, where Ref is the actual reference input seen by
+ * the WR PLL.
+ *
+ * We want R so that REF_MIN <= Ref <= REF_MAX.
+ * Injecting R2 = 2 * R gives:
+ * REF_MAX * r2 > LC_FREQ * 2 and
+ * REF_MIN * r2 < LC_FREQ * 2
+ *
+ * Which means the desired boundaries for r2 are:
+ * LC_FREQ * 2 / REF_MAX < r2 < LC_FREQ * 2 / REF_MIN
+ *
+ */
+ for (r2 = LC_FREQ * 2 / REF_MAX + 1;
+ r2 <= LC_FREQ * 2 / REF_MIN;
+ r2++) {
+
+ /*
+ * VCO = N * Ref, that is: VCO = N * LC_FREQ / R
+ *
+ * Once again we want VCO_MIN <= VCO <= VCO_MAX.
+ * Injecting R2 = 2 * R and N2 = 2 * N, we get:
+ * VCO_MAX * r2 > n2 * LC_FREQ and
+ * VCO_MIN * r2 < n2 * LC_FREQ)
+ *
+ * Which means the desired boundaries for n2 are:
+ * VCO_MIN * r2 / LC_FREQ < n2 < VCO_MAX * r2 / LC_FREQ
+ */
+ for (n2 = VCO_MIN * r2 / LC_FREQ + 1;
+ n2 <= VCO_MAX * r2 / LC_FREQ;
+ n2++) {
+
+ for (p = P_MIN; p <= P_MAX; p += P_INC)
+ wrpll_update_rnp(freq2k, budget,
+ r2, n2, p, &best);
+ }
+ }
- if (wrpll_tmds_clock_table[i].clock != clock)
- DRM_INFO("WRPLL: using settings for %dKHz on %dKHz mode\n",
- wrpll_tmds_clock_table[i].clock, clock);
+ *n2_out = best.n2;
+ *p_out = best.p;
+ *r2_out = best.r2;
- DRM_DEBUG_KMS("WRPLL: %dKHz refresh rate with p=%d, n2=%d r2=%d\n",
- clock, *p, *n2, *r2);
+ DRM_DEBUG_KMS("WRPLL: %dHz refresh rate with p=%d, n2=%d r2=%d\n",
+ clock, *p_out, *n2_out, *r2_out);
}
bool intel_ddi_pll_mode_set(struct drm_crtc *crtc, int clock)
@@ -851,7 +662,7 @@ bool intel_ddi_pll_mode_set(struct drm_crtc *crtc, int clock)
return true;
} else if (type == INTEL_OUTPUT_HDMI) {
- int p, n2, r2;
+ unsigned p, n2, r2;
if (plls->wrpll1_refcount == 0) {
DRM_DEBUG_KMS("Using WRPLL 1 on pipe %c\n",
@@ -873,7 +684,7 @@ bool intel_ddi_pll_mode_set(struct drm_crtc *crtc, int clock)
WARN(I915_READ(reg) & WRPLL_PLL_ENABLE,
"WRPLL already enabled\n");
- intel_ddi_calculate_wrpll(clock, &p, &n2, &r2);
+ intel_ddi_calculate_wrpll(clock * 1000, &r2, &n2, &p);
val = WRPLL_PLL_ENABLE | WRPLL_PLL_SELECT_LCPLL_2700 |
WRPLL_DIVIDER_REFERENCE(r2) | WRPLL_DIVIDER_FEEDBACK(n2) |
--
1.8.1.4
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