[V4,10/18] dma: support NEC PC-9821 interface

diff --git a/hw/dma.c b/hw/dma.c
index 44c642e..28219e7 100644
--- a/hw/dma.c
+++ b/hw/dma.c
@@ -45,6 +45,8 @@  struct dma_regs {
     uint8_t eop;
     DMA_transfer_handler transfer_handler;
     void *opaque;
+    /* NEC PC-9821 */
+    uint8_t bound;
 };
 
 #define ADDR 0
@@ -57,6 +59,9 @@  static struct dma_cont {
     uint8_t flip_flop;
     int dshift;
     struct dma_regs regs[4];
+    /* NEC PC-9821 */
+    uint8_t pc98;
+    uint8_t access_ctrl;
 } dma_controllers[2];
 
 enum {
@@ -74,6 +79,14 @@  enum {
 
 };
 
+enum {
+    MODE_DIR = 0x20,
+};
+
+enum {
+    PC98_DISABLE_DMA_OVER_1MB = 0x04,
+};
+
 static void DMA_run (void);
 
 static int channels[8] = {-1, 2, 3, 1, -1, -1, -1, 0};
@@ -329,7 +342,8 @@  void DMA_release_DREQ (int nchan)
 static void channel_run (int ncont, int ichan)
 {
     int n;
-    struct dma_regs *r = &dma_controllers[ncont].regs[ichan];
+    struct dma_cont *d = &dma_controllers[ncont];
+    struct dma_regs *r = &d->regs[ichan];
 #ifdef DEBUG_DMA
     int dir, opmode;
 
@@ -344,11 +358,26 @@  static void channel_run (int ncont, int ichan)
     }
 #endif
 
-    r = dma_controllers[ncont].regs + ichan;
     n = r->transfer_handler (r->opaque, ichan + (ncont << 2),
                              r->now[COUNT], (r->base[COUNT] + 1) << ncont);
     r->now[COUNT] = n;
     ldebug ("dma_pos %d size %d\n", n, (r->base[COUNT] + 1) << ncont);
+
+    /* increment page register */
+    if (d->pc98 && r->bound) {
+        uint32_t last_addr = r->base[ADDR];
+        if (r->mode & MODE_DIR) {
+            last_addr -= n >> ncont;
+            if (last_addr & 0xffff0000) {
+                r->page = ((r->page - 1) & r->bound) | (r->page & (~r->bound));
+            }
+        } else {
+            last_addr += n >> ncont;
+            if (last_addr & 0xffff0000) {
+                r->page = ((r->page + 1) & r->bound) | (r->page & (~r->bound));
+            }
+        }
+    }
 }
 
 static QEMUBH *dma_bh;
@@ -400,10 +429,14 @@  void DMA_register_channel (int nchan,
 
 int DMA_read_memory (int nchan, void *buf, int pos, int len)
 {
-    struct dma_regs *r = &dma_controllers[nchan > 3].regs[nchan & 3];
+    struct dma_cont *d = &dma_controllers[nchan > 3];
+    struct dma_regs *r = &d->regs[nchan & 3];
     target_phys_addr_t addr = ((r->pageh & 0x7f) << 24) | (r->page << 16) | r->now[ADDR];
 
-    if (r->mode & 0x20) {
+    if (d->pc98 && (d->access_ctrl & PC98_DISABLE_DMA_OVER_1MB)) {
+        addr &= 0xfffff;
+    }
+    if (r->mode & MODE_DIR) {
         int i;
         uint8_t *p = buf;
 
@@ -422,10 +455,14 @@  int DMA_read_memory (int nchan, void *buf, int pos, int len)
 
 int DMA_write_memory (int nchan, void *buf, int pos, int len)
 {
-    struct dma_regs *r = &dma_controllers[nchan > 3].regs[nchan & 3];
+    struct dma_cont *d = &dma_controllers[nchan > 3];
+    struct dma_regs *r = &d->regs[nchan & 3];
     target_phys_addr_t addr = ((r->pageh & 0x7f) << 24) | (r->page << 16) | r->now[ADDR];
 
-    if (r->mode & 0x20) {
+    if (d->pc98 && (d->access_ctrl & PC98_DISABLE_DMA_OVER_1MB)) {
+        addr &= 0xfffff;
+    }
+    if (r->mode & MODE_DIR) {
         int i;
         uint8_t *p = buf;
 
@@ -542,6 +579,8 @@  static const VMStateDescription vmstate_dma = {
 
 void DMA_init (int high_page_enable)
 {
+    dma_controllers[0].pc98 = 0;
+    dma_controllers[1].pc98 = 0;
     dma_init2(&dma_controllers[0], 0x00, 0, 0x80,
               high_page_enable ? 0x480 : -1);
     dma_init2(&dma_controllers[1], 0xc0, 1, 0x88,
@@ -551,3 +590,138 @@  void DMA_init (int high_page_enable)
 
     dma_bh = qemu_bh_new(DMA_run_bh, NULL);
 }
+
+/* NEC PC-9821 */
+
+static void pc98_write_port (void *opaque, uint32_t nport, uint32_t data)
+{
+    static const uint8_t bounds[4] = {0, 0x0f, 0, 0xff};
+    struct dma_cont *d = opaque;
+    int ichan;
+
+    switch (nport) {
+    case 0x01: case 0x03: case 0x05: case 0x07:
+    case 0x09: case 0x0b: case 0x0d: case 0x0f:
+        write_chan (d, nport >> 1, data);
+        break;
+    case 0x11: case 0x13: case 0x15: case 0x17:
+    case 0x19: case 0x1b: case 0x1d: case 0x1f:
+        write_cont (d, nport >> 1, data);
+        break;
+    case 0x21: case 0x23: case 0x25: case 0x27:
+        ichan = ((nport >> 1) + 1) & 3;
+        d->regs[ichan].page = data;
+        break;
+    case 0x29:
+        ichan = data & 3;
+        d->regs[ichan].bound = bounds[(data >> 2) & 3];
+        break;
+    case 0x439:
+        d->access_ctrl = data;
+        break;
+    case 0xe05: case 0xe07: case 0xe09: case 0xe0b:
+        ichan = ((nport >> 1) - 2) & 3;
+        d->regs[ichan].pageh = data;
+        break;
+    }
+}
+
+static uint32_t pc98_read_port (void *opaque, uint32_t nport)
+{
+    struct dma_cont *d = opaque;
+
+    switch (nport) {
+    case 0x01: case 0x03: case 0x05: case 0x07:
+    case 0x09: case 0x0b: case 0x0d: case 0x0f:
+        return read_chan (d, nport >> 1);
+    case 0x11: case 0x13: case 0x15: case 0x17:
+    case 0x19: case 0x1b: case 0x1d: case 0x1f:
+        return read_cont (d, nport >> 1);
+    case 0x439:
+        return d->access_ctrl;
+    }
+    return 0;
+}
+
+static void pc98_dma_reset(void *opaque)
+{
+    struct dma_cont *d = opaque;
+    int i;
+
+    for (i = 0; i < ARRAY_SIZE (d->regs); ++i) {
+        d->regs[i].bound = 0;
+    }
+    d->access_ctrl = 0xb4;
+    dma_reset(d);
+}
+
+static const VMStateDescription vmstate_pc98_dma_regs = {
+    .name = "dma_regs",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .minimum_version_id_old = 1,
+    .fields      = (VMStateField []) {
+        VMSTATE_INT32_ARRAY(now, struct dma_regs, 2),
+        VMSTATE_UINT16_ARRAY(base, struct dma_regs, 2),
+        VMSTATE_UINT8(mode, struct dma_regs),
+        VMSTATE_UINT8(page, struct dma_regs),
+        VMSTATE_UINT8(pageh, struct dma_regs),
+        VMSTATE_UINT8(dack, struct dma_regs),
+        VMSTATE_UINT8(eop, struct dma_regs),
+        /* PC-9821 */
+        VMSTATE_UINT8(bound, struct dma_regs),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static const VMStateDescription vmstate_pc98_dma = {
+    .name = "dma",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .minimum_version_id_old = 1,
+    .post_load = dma_post_load,
+    .fields      = (VMStateField []) {
+        VMSTATE_UINT8(command, struct dma_cont),
+        VMSTATE_UINT8(mask, struct dma_cont),
+        VMSTATE_UINT8(flip_flop, struct dma_cont),
+        VMSTATE_INT32(dshift, struct dma_cont),
+        VMSTATE_STRUCT_ARRAY(regs, struct dma_cont, 4, 1, vmstate_pc98_dma_regs, struct dma_regs),
+        /* PC-9821 */
+        VMSTATE_UINT8(access_ctrl, struct dma_cont),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+void pc98_DMA_init (int high_page_enable)
+{
+    struct dma_cont *d = &dma_controllers[0];
+    int i;
+
+    d->pc98 = 1;
+    d->dshift = 0;
+    for (i = 0; i < 8; i++) {
+        register_ioport_write (0x01 + (i << 1), 1, 1, pc98_write_port, d);
+        register_ioport_read (0x01 + (i << 1), 1, 1, pc98_read_port, d);
+        register_ioport_write (0x11 + (i << 1), 1, 1, pc98_write_port, d);
+        register_ioport_read (0x11 + (i << 1), 1, 1, pc98_read_port, d);
+    }
+    for (i = 0; i < 4; i++) {
+        register_ioport_write (0x21 + (i << 1), 1, 1, pc98_write_port, d);
+    }
+    register_ioport_write (0x29, 1, 1, pc98_write_port, d);
+    register_ioport_write (0x439, 1, 1, pc98_write_port, d);
+    register_ioport_read (0x439, 1, 1, pc98_read_port, d);
+    if (high_page_enable) {
+        for (i = 0; i < 4; i++) {
+            register_ioport_write (0xe05 + (i << 1), 1, 1, pc98_write_port, d);
+        }
+    }
+    qemu_register_reset(pc98_dma_reset, d);
+    pc98_dma_reset(d);
+    for (i = 0; i < ARRAY_SIZE (d->regs); ++i) {
+        d->regs[i].transfer_handler = dma_phony_handler;
+    }
+    vmstate_register (0, &vmstate_pc98_dma, &dma_controllers[0]);
+
+    dma_bh = qemu_bh_new(DMA_run_bh, NULL);
+}
diff --git a/hw/isa.h b/hw/isa.h
index 655ad62..10118b9 100644
--- a/hw/isa.h
+++ b/hw/isa.h
@@ -42,6 +42,7 @@  void DMA_hold_DREQ (int nchan);
 void DMA_release_DREQ (int nchan);
 void DMA_schedule(int nchan);
 void DMA_init (int high_page_enable);
+void pc98_DMA_init (int high_page_enable);
 void DMA_register_channel (int nchan,
                            DMA_transfer_handler transfer_handler,
                            void *opaque);