perfect ram timings

Source/Atmosphere/stratosphere/loader/source/oc/mtc_timing_value.hpp

@@ -113,7 +113,7 @@ namespace ams::ldr::hoc {
         const std::array<u32,       8> tRCD_values    = { 18, 17, 16, 15, 14, 13, 12, 11 };
         const std::array<u32,       8> tRP_values     = { 18, 17, 16, 15, 14, 13, 12, 11 };
         const std::array<u32,      10> tRAS_values    = { 42, 36, 34, 32, 30, 28, 26, 24, 22, 20 };
-        const std::array<double,    7>  tRRD_values   = { /*10.0,*/ 7.5, 6.0, 5.0, 4.0, 3.0, 2.0, 1.0 }; /* 10.0 is used for <2133mhz; do we care? 8gb uses 7.5 tRRD on >=1331. */
+        const std::array<double,    8>  tRRD_values   = { 10.0, 7.5, 6.0, 5.0, 4.0, 3.0, 2.0, 1.0 };
         const std::array<u32,      11>  tRFC_values   = { 140, 130, 120, 110, 100, 90, 80, 70, 60, 50, 40 };
         const std::array<u32,      10>  tWTR_values   = { 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 };
         const std::array<u32,       6>  tREFpb_values = { 3900, 5850, 7800, 11700, 15600, 99999 };

Source/Atmosphere/stratosphere/loader/source/oc/pcv/mariko/calculate_timings_mariko.cpp

@@ -15,18 +15,42 @@
  */
 
 #include <stratosphere.hpp>
+#include "../pcv.hpp"
 #include "../../mtc_timing_value.hpp"
 #include "timing_tables.hpp"
 
 namespace ams::ldr::hoc::pcv::mariko {
 
+    double GetMaxTrrd(u32 freq) {
+        DramId id = GetDramId();
+
+        if (freq >= 1866'000) {
+            return 7.5;
+        }
+
+        switch (id) {
+            case HOAG_4GB_HYNIX_H9HCNNNBKMMLXR_NEE ... IOWA_4GB_HYNIX_H9HCNNNBKMMLXR_NEE:
+            case IOWA_4GB_MICRON_MT53E512M32D2NP_046_WTE:
+            case HOAG_4GB_MICRON_MT53E512M32D2NP_046_WTE:
+            case IOWA_8GB_SAMSUNG_K4UBE3D4AA_MGCL:
+            case HOAG_8GB_SAMSUNG_K4UBE3D4AA_MGCL:
+            case AULA_8GB_SAMSUNG_K4UBE3D4AA_MGCL:
+            case IOWA_4GB_MICRON_MT53E512M32D1NP_046_WTB ... AULA_4GB_MICRON_MT53E512M32D1NP_046_WTB:
+                return 7.5;
+            default:
+                break;
+        }
+
+        return 10.0;
+    }
+
     void GetRext(u32 freq) {
         if (auto r = FindRext(freq)) {
             rext = r->rext;
             return;
         }
 
-        /* > 3200 */
+        /* Fallback */
         rext = 0x1E;
     }
 
@@ -46,9 +70,10 @@ namespace ams::ldr::hoc::pcv::mariko {
     }
 
     void AutoLatency(volatile u32 &latency, u32 freq, u32 latencyStep) {
-        if (freq > 1600'000 && freq <= 1896'000) { /* 1866tRWL */
+        if (freq > 1600'000 && freq <= 1866'000) { /* 1866tRWL */
             latency += latencyStep * 2;
         } else { /* 2133tRWL */
+            // Note: JEDEC/Datasheet mandates 2133 for >1866, even if <2133
             latency += latencyStep * 3;
         }
     }
@@ -139,7 +164,7 @@ namespace ams::ldr::hoc::pcv::mariko {
         tRCD   = tRCD_values[lowFreq ? C.low_t1_tRCD : C.t1_tRCD];
         tRPpb  = tRP_values[lowFreq  ? C.low_t2_tRP  : C.t2_tRP];
         tRAS   = tRAS_values[lowFreq ? C.low_t3_tRAS : C.t3_tRAS];
-        tRRD   = tRRD_values[lowFreq ? C.low_t4_tRRD : C.t4_tRRD];
+        tRRD   = MIN(tRRD_values[lowFreq ? C.low_t4_tRRD : C.t4_tRRD], GetMaxTrrd(freq));
         tRFCpb = tRFC_values[lowFreq ? C.low_t5_tRFC : C.t5_tRFC];
 
         u32 tRTW = lowFreq ? C.low_t6_tRTW : C.t6_tRTW;

Source/Atmosphere/stratosphere/loader/source/oc/pcv/mariko/pcv_mariko_mtc.hpp

@@ -26,6 +26,8 @@
 
 namespace ams::ldr::hoc::pcv::mariko {
 
+    DramId GetDramId();
+
     void MtcGenerateFreqTables();
     Result MemFreqMtcTable(u32 *ptr);
     Result MemFreqDvbTable(u32 *ptr);