From 0d5558f876f28ce3873350778bca079a672121e9 Mon Sep 17 00:00:00 2001
From: Lightos1 <124387232+Lightos1@users.noreply.github.com>
Date: Sat, 30 May 2026 17:39:49 +0200
Subject: [PATCH] pcv_erista: add experimental proper write timings

---
 .../oc/erista/calculate_timings_erista.cpp    | 39 +++++++++++++++++++
 .../loader/source/oc/mtc_timing_value.hpp     |  8 ++++
 .../loader/source/oc/pcv/pcv_erista.cpp       | 12 +++---
 3 files changed, 54 insertions(+), 5 deletions(-)

diff --git a/Source/Atmosphere/stratosphere/loader/source/oc/erista/calculate_timings_erista.cpp b/Source/Atmosphere/stratosphere/loader/source/oc/erista/calculate_timings_erista.cpp
index 74e0cb91..a8106726 100644
--- a/Source/Atmosphere/stratosphere/loader/source/oc/erista/calculate_timings_erista.cpp
+++ b/Source/Atmosphere/stratosphere/loader/source/oc/erista/calculate_timings_erista.cpp
@@ -82,11 +82,42 @@ namespace ams::ldr::hoc::pcv::erista {
         }
     }
 
+    void CalculateMrw2() {
+        static const u8 rlMapDBI[8] = {
+            6, 12, 16, 22, 28, 32, 36, 40
+        };
+
+        static const u8 wlMapSetA[8] = {
+            4, 6, 8, 10, 12, 14, 16, 18
+        };
+
+        u32 rlIndex = 0;
+        u32 wlIndex = 0;
+
+        for (u32 i = 0; i < std::size(rlMapDBI); ++i) {
+            if (rlMapDBI[i] == 32) {
+                rlIndex = i;
+                break;
+            }
+        }
+
+        for (u32 i = 0; i < std::size(wlMapSetA); ++i) {
+            if (wlMapSetA[i] == WL) {
+                wlIndex = i;
+                break;
+            }
+        }
+
+        /* DBI is always enabled. */
+        mrw2 = static_cast<u8>(((rlIndex & 0x7) | ((wlIndex & 0x7) << 3) | ((0 & 0x1) << 6)));
+    }
+
     void CalculateTimings(double tCK_avg, u32 freq) {
         RL = RL_1331;
         WL = WL_1331;
 
         HandleLatency(freq);
+        CalculateMrw2();
 
         tR2P = CEIL((RL * 0.426) - 2.0);
         tR2W = FLOOR(FLOOR((5.0 / tCK_avg) + ((FLOOR(48.0 / WL) - 0.478) * 3.0)) / 1.501) + RL - (C.t6_tRTW * 3) + finetRTW;
@@ -95,6 +126,14 @@ namespace ams::ldr::hoc::pcv::erista {
         tWTPDEN = CEIL(((1.803 / tCK_avg) + MAX(RL + (2.694 / tCK_avg), static_cast<double>(tW2P))) + (BL / 2));
         tW2R    = FLOOR(MAX((5.020 / tCK_avg) + 1.130, WL - MAX(-CEIL(0.258 * (WL - RL)), 1.964)) * 1.964) + WL - CEIL(tWTR / tCK_avg) + finetWTR;
 
+        wdv = WL;
+        wsv = WL - 2;
+        wev = 0xA + (WL - 14);
+
+        u32 obdlyHigh = 3 / FLOOR(MIN(static_cast<double>(2), tCK_avg * (WL - 7)));
+        u32 obdlyLow  = MAX(WL - FLOOR((126.0 / CEIL(tCK_avg + 8.601))), 0.0);
+        obdly         = PACK_U32_NIBBLE_HIGH_BYTE_LOW(obdlyHigh, obdlyLow);
+
         pdex2rw  = CEIL((CEIL(12.335 - tCK_avg) + (7.430 / tCK_avg) - CEIL(tCK_avg * 11.361)));
         tCLKSTOP = FLOOR(MIN(8.488 / tCK_avg, 23.0)) + 8.0;
 
diff --git a/Source/Atmosphere/stratosphere/loader/source/oc/mtc_timing_value.hpp b/Source/Atmosphere/stratosphere/loader/source/oc/mtc_timing_value.hpp
index 15da084e..623c18a0 100644
--- a/Source/Atmosphere/stratosphere/loader/source/oc/mtc_timing_value.hpp
+++ b/Source/Atmosphere/stratosphere/loader/source/oc/mtc_timing_value.hpp
@@ -94,11 +94,19 @@ namespace ams::ldr::hoc {
         inline u32 tWTPDEN;
         inline u32 tW2R;
 
+        inline u32 wdv;
+        inline u32 wsv;
+        inline u32 wev;
+
+        inline u32 obdly;
+
         inline u32 pdex2rw;
 
         inline u32 tCLKSTOP;
 
         inline double pdex2mrr;
+
+        inline u8 mrw2;
     }
 
     namespace pcv::mariko {
diff --git a/Source/Atmosphere/stratosphere/loader/source/oc/pcv/pcv_erista.cpp b/Source/Atmosphere/stratosphere/loader/source/oc/pcv/pcv_erista.cpp
index e0348295..b453aea0 100644
--- a/Source/Atmosphere/stratosphere/loader/source/oc/pcv/pcv_erista.cpp
+++ b/Source/Atmosphere/stratosphere/loader/source/oc/pcv/pcv_erista.cpp
@@ -257,16 +257,17 @@ namespace ams::ldr::hoc::pcv::erista {
         WRITE_PARAM_ALL_REG(table, emc_rw2pden, tWTPDEN);
 
         /* Accept imperfection or prepare for suffering. */
+        #if defined(AMS_BUILD_FOR_AUDITING) || defined(AMS_BUILD_FOR_DEBUGGING)
         // WRITE_PARAM_ALL_REG(table, emc_einput, einput);
         // WRITE_PARAM_ALL_REG(table, emc_einput_duration, einput_duration);
-        // WRITE_PARAM_ALL_REG(table, emc_obdly, obdly);
+        WRITE_PARAM_ALL_REG(table, emc_obdly, obdly);
         // WRITE_PARAM_ALL_REG(table, emc_ibdly, ibdly);
         // WRITE_PARAM_ALL_REG(table, emc_wdv_mask, wdv);
         // WRITE_PARAM_ALL_REG(table, emc_quse_width, quse_width);
         // WRITE_PARAM_ALL_REG(table, emc_quse, quse);
-        // WRITE_PARAM_ALL_REG(table, emc_wdv, wdv);
-        // WRITE_PARAM_ALL_REG(table, emc_wsv, wsv);
-        // WRITE_PARAM_ALL_REG(table, emc_wev, wev);
+        WRITE_PARAM_ALL_REG(table, emc_wdv, wdv);
+        WRITE_PARAM_ALL_REG(table, emc_wsv, wsv);
+        WRITE_PARAM_ALL_REG(table, emc_wev, wev);
         // WRITE_PARAM_ALL_REG(table, emc_qrst, qrst);
         // WRITE_PARAM_ALL_REG(table, emc_tr_qrst, qrst);
         // WRITE_PARAM_ALL_REG(table, emc_qsafe, qsafe);
@@ -279,8 +280,9 @@ namespace ams::ldr::hoc::pcv::erista {
         // WRITE_PARAM_ALL_REG(table, emc_rdv_early_mask, rdv);
         // WRITE_PARAM_ALL_REG(table, emc_rdv_mask, rdv + 2);
         // WRITE_PARAM_ALL_REG(table, emc_tr_rdv, rdv);
-        // table->emc_mrw2 = (table->emc_mrw2 & ~0xFFu) | static_cast<u32>(mrw2);
+        table->emc_mrw2 = (table->emc_mrw2 & ~0xFFu) | static_cast<u32>(mrw2);
         // table->dram_timings.rl = RL;
+        #endif
 
         constexpr double MC_ARB_DIV = 4.0;
         constexpr u32 MC_ARB_SFA    = 2;