Initial commit

2026-06-02 17:26:51 +02:00 · 2025-10-11 13:23:06 +02:00
commit cecac10408
9 changed files with 665 additions and 0 deletions
--- a/source/iointerface.c
+++ b/source/iointerface.c
@@ -0,0 +1,129 @@
+#include <nds/ndstypes.h>
+#include "card.h"
+
+#define DSPICO_CMD_REQUEST_SD_READ(sector)      (0xE300000000000000ull | (sector))
+#define DSPICO_CMD_POLL_SD_READY                0xE400000000000000ull
+#define DSPICO_CMD_GET_SD_DATA                  0xE500000000000000ull
+#define DSPICO_CMD_WRITE_SD_DATA(sector, isFirst, isLast)\
+    (0xF6E10D9800000000ull | ((isFirst ? 1ULL : 0ULL) << 33) | ((isLast ? 1ULL : 0ULL) << 32) | (sector))
+
+__attribute__((noinline)) static void requestSdRead(u32 sector)
+{
+    card_romSetCmd(DSPICO_CMD_REQUEST_SD_READ(sector));
+    card_romStartXfer(MCCNT1_DIR_READ | MCCNT1_RESET_OFF | MCCNT1_CLK_6_7_MHZ | MCCNT1_LEN_0 | MCCNT1_CMD_SCRAMBLE |
+        MCCNT1_LATENCY2(0) | MCCNT1_CLOCK_SCRAMBLER | MCCNT1_READ_DATA_DESCRAMBLE | MCCNT1_LATENCY1(0), false);
+    card_romWaitBusy();
+}
+
+__attribute__((noinline)) static u32 pollSdDataReady(void)
+{
+    u32 result;
+    card_romSetCmd(DSPICO_CMD_POLL_SD_READY);
+    card_romStartXfer(MCCNT1_DIR_READ | MCCNT1_RESET_OFF | MCCNT1_CLK_6_7_MHZ | MCCNT1_LEN_4 | MCCNT1_CMD_SCRAMBLE |
+        MCCNT1_LATENCY2(4) | MCCNT1_CLOCK_SCRAMBLER | MCCNT1_READ_DATA_DESCRAMBLE | MCCNT1_LATENCY1(0), false);
+    card_romCpuRead(&result, 1);
+    return result;
+}
+
+__attribute__((noinline)) static void getSdData(u8* dst)
+{
+    card_romSetCmd(DSPICO_CMD_GET_SD_DATA);
+    card_romStartXfer(MCCNT1_DIR_READ | MCCNT1_RESET_OFF | MCCNT1_CLK_6_7_MHZ | MCCNT1_LEN_512 | MCCNT1_CMD_SCRAMBLE |
+        MCCNT1_LATENCY2(4) | MCCNT1_CLOCK_SCRAMBLER | MCCNT1_LATENCY1(0), false);
+    if ((u32)dst & 3)
+    {
+        card_romCpuReadUnaligned(dst, 128);
+    }
+    else
+    {
+        card_romCpuRead((u32*)dst, 128);
+    }
+}
+
+static void writeSdData(u32 sector, const u8* src, bool isFirst, bool isLast)
+{
+    card_romSetCmd(DSPICO_CMD_WRITE_SD_DATA(sector, isFirst, isLast));
+    card_romStartXfer(MCCNT1_DIR_WRITE | MCCNT1_RESET_OFF | MCCNT1_CLK_6_7_MHZ | MCCNT1_LEN_512 | MCCNT1_CMD_SCRAMBLE |
+        MCCNT1_LATENCY2(8) | MCCNT1_CLOCK_SCRAMBLER | MCCNT1_READ_DATA_DESCRAMBLE | MCCNT1_LATENCY1(0), false);
+    if ((u32)src & 3)
+    {
+        card_romCpuWriteUnaligned(src, 128);
+    }
+    else
+    {
+        card_romCpuWrite((const u32*)src, 128);
+    }
+}
+
+bool dldi_startup(void)
+{
+    return true;
+}
+
+bool dldi_isInserted(void)
+{
+    return true;
+}
+
+bool dldi_clearStatus(void)
+{
+    return true;
+}
+
+bool dldi_readSectors(u32 sector, u32 numSectors, void* buffer)
+{
+    u8* ptr = (u8*)buffer;
+
+    requestSdRead(sector);
+
+    do
+    {
+        while (!pollSdDataReady());
+        getSdData(ptr);
+        ptr += 512;
+    } while (--numSectors);
+
+    // Important! This makes sure that SdCard has returned
+    // to State::Idle. Otherwise the next transfer may fail.
+    while (!pollSdDataReady());
+
+    return true;
+}
+
+bool dldi_writeSectors(u32 sector, u32 numSectors, void* buffer)
+{
+    if (numSectors > 0)
+    {
+        const u8* ptr = (const u8*)buffer;
+        if (numSectors == 1)
+        {
+            writeSdData(sector, ptr, true, true); // send 0 = last
+        }
+        else
+        {
+            writeSdData(sector, ptr, true, false); // send 0
+            sector++;
+            ptr += 512;
+
+            for (u32 i = 1; i < numSectors - 1; i++)
+            {
+                writeSdData(sector, ptr, false, false); // send i
+                sector++;
+                ptr += 512;
+                while (!pollSdDataReady()); // wait i - 1
+            }
+
+            writeSdData(sector, ptr, false, true); // send last
+            while (!pollSdDataReady()); // wait last - 1
+        }
+
+        while (!pollSdDataReady()); // wait last
+    }
+
+    return true;
+}
+
+bool dldi_shutdown(void)
+{
+    return true;
+}