diff options
| -rw-r--r-- | drivers/gpu/drm/i915/intel_ddi.c | 211 |
1 files changed, 137 insertions, 74 deletions
diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c index 31b29e8781ac..6e964ef7dfda 100644 --- a/drivers/gpu/drm/i915/intel_ddi.c +++ b/drivers/gpu/drm/i915/intel_ddi.c @@ -1104,6 +1104,103 @@ hsw_ddi_pll_select(struct intel_crtc *intel_crtc, return true; } +struct skl_wrpll_context { + uint64_t min_deviation; /* current minimal deviation */ + uint64_t central_freq; /* chosen central freq */ + uint64_t dco_freq; /* chosen dco freq */ + unsigned int p; /* chosen divider */ +}; + +static void skl_wrpll_context_init(struct skl_wrpll_context *ctx) +{ + memset(ctx, 0, sizeof(*ctx)); + + ctx->min_deviation = U64_MAX; +} + +/* DCO freq must be within +1%/-6% of the DCO central freq */ +#define SKL_DCO_MAX_PDEVIATION 100 +#define SKL_DCO_MAX_NDEVIATION 600 + +static void skl_wrpll_try_divider(struct skl_wrpll_context *ctx, + uint64_t central_freq, + uint64_t dco_freq, + unsigned int divider) +{ + uint64_t deviation; + + deviation = div64_u64(10000 * abs_diff(dco_freq, central_freq), + central_freq); + + /* positive deviation */ + if (dco_freq >= central_freq) { + if (deviation < SKL_DCO_MAX_PDEVIATION && + deviation < ctx->min_deviation) { + ctx->min_deviation = deviation; + ctx->central_freq = central_freq; + ctx->dco_freq = dco_freq; + ctx->p = divider; + } + /* negative deviation */ + } else if (deviation < SKL_DCO_MAX_NDEVIATION && + deviation < ctx->min_deviation) { + ctx->min_deviation = deviation; + ctx->central_freq = central_freq; + ctx->dco_freq = dco_freq; + ctx->p = divider; + } + +} + +static void skl_wrpll_get_multipliers(unsigned int p, + unsigned int *p0 /* out */, + unsigned int *p1 /* out */, + unsigned int *p2 /* out */) +{ + /* even dividers */ + if (p % 2 == 0) { + unsigned int half = p / 2; + + if (half == 1 || half == 2 || half == 3 || half == 5) { + *p0 = 2; + *p1 = 1; + *p2 = half; + } else if (half % 2 == 0) { + *p0 = 2; + *p1 = half / 2; + *p2 = 2; + } else if (half % 3 == 0) { + *p0 = 3; + *p1 = half / 3; + *p2 = 2; + } else if (half % 7 == 0) { + *p0 = 7; + *p1 = half / 7; + *p2 = 2; + } + } else if (p == 3 || p == 9) { /* 3, 5, 7, 9, 15, 21, 35 */ + *p0 = 3; + *p1 = 1; + *p2 = p / 3; + } else if (p == 5 || p == 7) { + *p0 = p; + *p1 = 1; + *p2 = 1; + } else if (p == 15) { + *p0 = 3; + *p1 = 1; + *p2 = 5; + } else if (p == 21) { + *p0 = 7; + *p1 = 1; + *p2 = 3; + } else if (p == 35) { + *p0 = 7; + *p1 = 1; + *p2 = 5; + } +} + struct skl_wrpll_params { uint32_t dco_fraction; uint32_t dco_integer; @@ -1189,90 +1286,56 @@ skl_ddi_calculate_wrpll(int clock /* in Hz */, uint64_t dco_central_freq[3] = {8400000000ULL, 9000000000ULL, 9600000000ULL}; - uint32_t min_dco_deviation = 400; - uint32_t min_dco_index = 3; - uint32_t P0[4] = {1, 2, 3, 7}; - uint32_t P2[4] = {1, 2, 3, 5}; - bool found = false; - uint32_t candidate_p = 0; - uint32_t candidate_p0[3] = {0}, candidate_p1[3] = {0}; - uint32_t candidate_p2[3] = {0}; - uint32_t dco_central_freq_deviation[3]; - uint32_t i, P1, k, dco_count; - bool retry_with_odd = false; - - /* Determine P0, P1 or P2 */ - for (dco_count = 0; dco_count < 3; dco_count++) { - found = false; - candidate_p = - div64_u64(dco_central_freq[dco_count], afe_clock); - if (retry_with_odd == false) - candidate_p = (candidate_p % 2 == 0 ? - candidate_p : candidate_p + 1); - - for (P1 = 1; P1 < candidate_p; P1++) { - for (i = 0; i < 4; i++) { - if (!(P0[i] != 1 || P1 == 1)) - continue; - - for (k = 0; k < 4; k++) { - if (P1 != 1 && P2[k] != 2) - continue; - - if (candidate_p == P0[i] * P1 * P2[k]) { - /* Found possible P0, P1, P2 */ - found = true; - candidate_p0[dco_count] = P0[i]; - candidate_p1[dco_count] = P1; - candidate_p2[dco_count] = P2[k]; - goto found; - } - - } - } - } - -found: - if (found) { - dco_central_freq_deviation[dco_count] = - div64_u64(10000 * - abs_diff(candidate_p * afe_clock, - dco_central_freq[dco_count]), - dco_central_freq[dco_count]); - - if (dco_central_freq_deviation[dco_count] < - min_dco_deviation) { - min_dco_deviation = - dco_central_freq_deviation[dco_count]; - min_dco_index = dco_count; + static const int even_dividers[] = { 4, 6, 8, 10, 12, 14, 16, 18, 20, + 24, 28, 30, 32, 36, 40, 42, 44, + 48, 52, 54, 56, 60, 64, 66, 68, + 70, 72, 76, 78, 80, 84, 88, 90, + 92, 96, 98 }; + static const int odd_dividers[] = { 3, 5, 7, 9, 15, 21, 35 }; + static const struct { + const int *list; + int n_dividers; + } dividers[] = { + { even_dividers, ARRAY_SIZE(even_dividers) }, + { odd_dividers, ARRAY_SIZE(odd_dividers) }, + }; + struct skl_wrpll_context ctx; + unsigned int dco, d, i; + unsigned int p0, p1, p2; + + skl_wrpll_context_init(&ctx); + + for (d = 0; d < ARRAY_SIZE(dividers); d++) { + for (dco = 0; dco < ARRAY_SIZE(dco_central_freq); dco++) { + for (i = 0; i < dividers[d].n_dividers; i++) { + unsigned int p = dividers[d].list[i]; + uint64_t dco_freq = p * afe_clock; + + skl_wrpll_try_divider(&ctx, + dco_central_freq[dco], + dco_freq, + p); } } - - if (min_dco_index > 2 && dco_count == 2) { - /* oh well, we tried... */ - if (retry_with_odd) - break; - - retry_with_odd = true; - dco_count = 0; - } } - if (WARN(min_dco_index > 2, - "No valid parameters found for pixel clock: %dHz\n", clock)) + if (!ctx.p) { + DRM_DEBUG_DRIVER("No valid divider found for %dHz\n", clock); return false; + } - 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]); + /* + * gcc incorrectly analyses that these can be used without being + * initialized. To be fair, it's hard to guess. + */ + p0 = p1 = p2 = 0; + skl_wrpll_get_multipliers(ctx.p, &p0, &p1, &p2); + skl_wrpll_params_populate(wrpll_params, afe_clock, ctx.central_freq, + p0, p1, p2); return true; } - static bool skl_ddi_pll_select(struct intel_crtc *intel_crtc, struct intel_crtc_state *crtc_state, |