Implement DBDMA channel registers.

devices/dbdma.cpp

@@ -0,0 +1,139 @@
+/*
+DingusPPC - The Experimental PowerPC Macintosh emulator
+Copyright (C) 2018-20 divingkatae and maximum
+                      (theweirdo)     spatium
+
+(Contact divingkatae#1017 or powermax#2286 on Discord for more info)
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+/** @file Descriptor-based direct memory access emulation. */
+
+#include <cinttypes>
+#include <thirdparty/loguru.hpp>
+#include "dbdma.h"
+#include "endianswap.h"
+
+uint32_t DMAChannel::reg_read(uint32_t offset, int size)
+{
+    uint32_t res = 0;
+
+    if (size != 4) {
+        LOG_F(WARNING, "Unsupported non-DWORD read from DMA channel");
+        return 0;
+    }
+
+    switch(offset) {
+    case DMAReg::CH_CTRL:
+        res = 0; /* ChannelControl reads as 0 (DBDMA spec 5.5.1, table 74) */
+        break;
+    case DMAReg::CH_STAT:
+        res = BYTESWAP_32(this->ch_stat);
+        break;
+    default:
+        LOG_F(WARNING, "Unsupported DMA channel register 0x%X", offset);
+    }
+
+    return res;
+}
+
+void DMAChannel::reg_write(uint32_t offset, uint32_t value, int size)
+{
+    uint16_t mask, old_stat, new_stat;
+
+    if (size != 4) {
+        LOG_F(WARNING, "Unsupported non-DWORD write to DMA channel");
+        return;
+    }
+
+    value = BYTESWAP_32(value);
+    old_stat = this->ch_stat;
+
+    switch(offset) {
+    case DMAReg::CH_CTRL:
+        mask = value >> 16;
+        new_stat = (value & mask & 0xF0FFU) | (old_stat & ~mask);
+        LOG_F(INFO, "New ChannelStatus value = 0x%X", new_stat);
+
+        if ((new_stat & CH_STAT_RUN) != (old_stat & CH_STAT_RUN)) {
+            if (new_stat & CH_STAT_RUN) {
+                new_stat |= CH_STAT_ACTIVE;
+                this->ch_stat = new_stat;
+                this->start();
+            } else {
+                new_stat &= ~CH_STAT_ACTIVE;
+                new_stat &= ~CH_STAT_DEAD;
+                this->ch_stat = new_stat;
+                this->abort();
+            }
+        } else if ((new_stat & CH_STAT_WAKE) != (old_stat & CH_STAT_WAKE)) {
+            new_stat |= CH_STAT_ACTIVE;
+            this->ch_stat = new_stat;
+            this->resume();
+        } else if ((new_stat & CH_STAT_PAUSE) != (old_stat & CH_STAT_PAUSE)) {
+            if (new_stat & CH_STAT_PAUSE) {
+                new_stat &= ~CH_STAT_ACTIVE;
+                this->ch_stat = new_stat;
+                this->pause();
+            }
+        }
+        if (new_stat & CH_STAT_FLUSH) {
+            LOG_F(WARNING, "DMA flush not implemented!");
+            new_stat &= ~CH_STAT_FLUSH;
+            this->ch_stat = new_stat;
+        }
+        break;
+    case DMAReg::CH_STAT:
+        break; /* ingore writes to ChannelStatus */
+    case DMAReg::CMD_PTR_LO:
+        if (!(this->ch_stat & CH_STAT_RUN) && !(this->ch_stat & CH_STAT_ACTIVE)) {
+            this->cmd_ptr = BYTESWAP_32(value);
+            LOG_F(INFO, "CommandPtrLo set to 0x%X", this->cmd_ptr);
+        }
+        break;
+    default:
+        LOG_F(WARNING, "Unsupported DMA channel register 0x%X", offset);
+    }
+}
+
+void DMAChannel::start()
+{
+    if (this->ch_stat & CH_STAT_PAUSE) {
+        LOG_F(WARNING, "Cannot start DMA channel, PAUSE bit is set");
+        return;
+    }
+
+    LOG_F(INFO, "Starting DMA channel, stat = 0x%X", this->ch_stat);
+}
+
+void DMAChannel::resume()
+{
+    if (this->ch_stat & CH_STAT_PAUSE) {
+        LOG_F(WARNING, "Cannot resume DMA channel, PAUSE bit is set");
+        return;
+    }
+
+    LOG_F(INFO, "Resuming DMA channel");
+}
+
+void DMAChannel::abort()
+{
+    LOG_F(INFO, "Aborting DMA channel");
+}
+
+void DMAChannel::pause()
+{
+    LOG_F(INFO, "Pausing DMA channel");
+}

devices/dbdma.h

@@ -0,0 +1,70 @@
+/*
+DingusPPC - The Experimental PowerPC Macintosh emulator
+Copyright (C) 2018-20 divingkatae and maximum
+                      (theweirdo)     spatium
+
+(Contact divingkatae#1017 or powermax#2286 on Discord for more info)
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+/** @file Descriptor-based direct memory access emulation.
+
+    Official documentation can be found in the fifth chapter of the book
+    "Macintosh Technology in the Common Hardware Reference Platform"
+    by Apple Computer, Inc.
+ */
+
+#ifndef DB_DMA_H
+#define DB_DMA_H
+
+#include <cinttypes>
+
+/** DBDMA Channel registers offsets */
+enum DMAReg : uint32_t {
+    CH_CTRL     =  0,
+    CH_STAT     =  4,
+    CMD_PTR_LO  = 12,
+};
+
+/** Channel Status bits (DBDMA spec, 5.5.3) */
+enum {
+    CH_STAT_ACTIVE  =  0x400,
+    CH_STAT_DEAD    =  0x800,
+    CH_STAT_WAKE    = 0x1000,
+    CH_STAT_FLUSH   = 0x2000,
+    CH_STAT_PAUSE   = 0x4000,
+    CH_STAT_RUN     = 0x8000
+};
+
+class DMAChannel {
+public:
+    DMAChannel() = default;
+    ~DMAChannel() = default;
+
+    uint32_t reg_read(uint32_t offset, int size);
+    void reg_write(uint32_t offset, uint32_t value, int size);
+
+protected:
+    void start(void);
+    void resume(void);
+    void abort(void);
+    void pause(void);
+
+private:
+    uint16_t    ch_stat = 0;
+    uint32_t    cmd_ptr = 0;
+};
+
+#endif /* DB_DMA_H */

devices/heathrow.cpp

@@ -25,6 +25,7 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #include "macio.h"
 #include "viacuda.h"
 #include "awacs.h"
+#include "dbdma.h"
 #include "machines/machinebase.h"
 
 /** Heathrow Mac I/O device emulation.
@@ -42,6 +43,7 @@ HeathrowIC::HeathrowIC() : PCIDevice("mac-io/heathrow")
     gMachineObj->add_subdevice("ViaCuda", this->viacuda);
 
     this->screamer = new AWACDevice();
+    this->snd_out_dma = new DMAChannel();
 }
 
 HeathrowIC::~HeathrowIC()
@@ -83,6 +85,33 @@ void HeathrowIC::pci_cfg_write(uint32_t reg_offs, uint32_t value, uint32_t size)
     }
 }
 
+uint32_t HeathrowIC::dma_read(uint32_t offset, int size)
+{
+    uint32_t res = 0;
+
+    switch(offset >> 8) {
+    case 8:
+        res = this->snd_out_dma->reg_read(offset & 0xFF, size);
+        break;
+    default:
+        LOG_F(WARNING, "Unsupported DMA channel read, offset=0x%X", offset);
+    }
+
+    return res;
+}
+
+void HeathrowIC::dma_write(uint32_t offset, uint32_t value, int size)
+{
+    switch(offset >> 8) {
+    case 8:
+        this->snd_out_dma->reg_write(offset & 0xFF, value, size);
+        break;
+    default:
+        LOG_F(WARNING, "Unsupported DMA channel write, offset=0x%X, val=0x%X", offset, value);
+    }
+}
+
+
 uint32_t HeathrowIC::read(uint32_t offset, int size)
 {
     uint32_t res = 0;
@@ -96,7 +125,7 @@ uint32_t HeathrowIC::read(uint32_t offset, int size)
         res = mio_ctrl_read(offset, size);
         break;
     case 8:
-        LOG_F(WARNING, "Attempting to read DMA channel register space \n");
+        res = dma_read(offset - 0x8000, size);
         break;
     case 0x14:
         res = this->screamer->snd_ctrl_read(offset - 0x14000, size);
@@ -128,7 +157,7 @@ void HeathrowIC::write(uint32_t offset, uint32_t value, int size)
         mio_ctrl_write(offset, value, size);
         break;
     case 8:
-        LOG_F(WARNING, "Attempting to write to DMA channel register space \n");
+        dma_write(offset - 0x8000, value, size);
         break;
     case 0x14:
         this->screamer->snd_ctrl_write(offset - 0x14000, value, size);

devices/macio.h

@@ -60,6 +60,7 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #include "viacuda.h"
 #include "nvram.h"
 #include "awacs.h"
+#include "dbdma.h"
 
 /**
     Heathrow ASIC emulation
@@ -104,6 +105,9 @@ public:
     void write(uint32_t offset, uint32_t value, int size);
 
 protected:
+    uint32_t dma_read(uint32_t offset, int size);
+    void dma_write(uint32_t offset, uint32_t value, int size);
+
     uint32_t mio_ctrl_read(uint32_t offset, int size);
     void mio_ctrl_write(uint32_t offset, uint32_t value, int size);
 
@@ -130,6 +134,8 @@ private:
     ViaCuda *viacuda;     /* VIA cell with Cuda MCU attached to it */
     NVram   *nvram;       /* NVRAM cell */
     AWACDevice *screamer; /* Screamer audio codec instance */
+
+    DMAChannel  *snd_out_dma;
 };
 
 #endif /* MACIO_H */