swim: split into separate IWM and ISM register blocks

The swim chip provides an implementation of both Apple's IWM and ISM floppy disk
controllers. Split the existing implementation into separate register banks for
each controller, whilst also switching the IWM registers from 16-bit to 8-bit
as implemented in real hardware.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-ID: <20231004083806.757242-13-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

3 files changed, 58 insertions, 46 deletions

diff --git a/hw/block/swim.c b/hw/block/swim.c
index 7df36ea..505718b 100644
--- a/hw/block/swim.c
+++ b/hw/block/swim.c
@@ -126,7 +126,14 @@
 #define SWIM_HEDSEL          0x20
 #define SWIM_MOTON           0x80
 
-static const char *swim_reg_names[] = {
+static const char *iwm_reg_names[] = {
+    "PH0L", "PH0H", "PH1L", "PH1H",
+    "PH2L", "PH2H", "PH3L", "PH3H",
+    "MTROFF", "MTRON", "INTDRIVE", "EXTDRIVE",
+    "Q6L", "Q6H", "Q7L", "Q7H"
+};
+
+static const char *ism_reg_names[] = {
     "WRITE_DATA", "WRITE_MARK", "WRITE_CRC", "WRITE_PARAMETER",
     "WRITE_PHASE", "WRITE_SETUP", "WRITE_MODE0", "WRITE_MODE1",
     "READ_DATA", "READ_MARK", "READ_ERROR", "READ_PARAMETER",
@@ -274,12 +281,11 @@ static void iwmctrl_write(void *opaque, hwaddr reg, uint64_t value,
 
     reg >>= REG_SHIFT;
 
-    swimctrl->regs[reg >> 1] = reg & 1;
-    trace_swim_iwmctrl_write((reg >> 1), size, (reg & 1));
+    swimctrl->iwmregs[reg] = value;
+    trace_swim_iwmctrl_write(reg, iwm_reg_names[reg], size, value);
 
-    if (swimctrl->regs[IWM_Q6] &&
-        swimctrl->regs[IWM_Q7]) {
-        if (swimctrl->regs[IWM_MTR]) {
+    if (swimctrl->iwmregs[IWM_Q7H]) {
+        if (swimctrl->iwmregs[IWM_MTRON]) {
             /* data register */
             swimctrl->iwm_data = value;
         } else {
@@ -307,6 +313,12 @@ static void iwmctrl_write(void *opaque, hwaddr reg, uint64_t value,
                     swimctrl->mode = SWIM_MODE_SWIM;
                     swimctrl->iwm_switch = 0;
                     trace_swim_iwm_switch();
+
+                    /* Switch to ISM registers */
+                    memory_region_del_subregion(&swimctrl->swim,
+                                                &swimctrl->iwm);
+                    memory_region_add_subregion(&swimctrl->swim, 0x0,
+                                                &swimctrl->ism);
                 }
                 break;
             }
@@ -317,28 +329,30 @@ static void iwmctrl_write(void *opaque, hwaddr reg, uint64_t value,
 static uint64_t iwmctrl_read(void *opaque, hwaddr reg, unsigned size)
 {
     SWIMCtrl *swimctrl = opaque;
+    uint8_t value;
 
     reg >>= REG_SHIFT;
 
-    swimctrl->regs[reg >> 1] = reg & 1;
+    value = swimctrl->iwmregs[reg];
+    trace_swim_iwmctrl_read(reg, iwm_reg_names[reg], size, value);
 
-    trace_swim_iwmctrl_read((reg >> 1), size, (reg & 1));
-    return 0;
+    return value;
 }
 
-static void swimctrl_write(void *opaque, hwaddr reg, uint64_t value,
-                           unsigned size)
+static const MemoryRegionOps swimctrl_iwm_ops = {
+    .write = iwmctrl_write,
+    .read = iwmctrl_read,
+    .endianness = DEVICE_BIG_ENDIAN,
+};
+
+static void ismctrl_write(void *opaque, hwaddr reg, uint64_t value,
+                          unsigned size)
 {
     SWIMCtrl *swimctrl = opaque;
 
-    if (swimctrl->mode == SWIM_MODE_IWM) {
-        iwmctrl_write(opaque, reg, value, size);
-        return;
-    }
-
     reg >>= REG_SHIFT;
 
-    trace_swim_swimctrl_write(reg, swim_reg_names[reg], size, value);
+    trace_swim_swimctrl_write(reg, ism_reg_names[reg], size, value);
 
     switch (reg) {
     case SWIM_WRITE_PHASE:
@@ -359,15 +373,11 @@ static void swimctrl_write(void *opaque, hwaddr reg, uint64_t value,
     }
 }
 
-static uint64_t swimctrl_read(void *opaque, hwaddr reg, unsigned size)
+static uint64_t ismctrl_read(void *opaque, hwaddr reg, unsigned size)
 {
     SWIMCtrl *swimctrl = opaque;
     uint32_t value = 0;
 
-    if (swimctrl->mode == SWIM_MODE_IWM) {
-        return iwmctrl_read(opaque, reg, size);
-    }
-
     reg >>= REG_SHIFT;
 
     switch (reg) {
@@ -389,14 +399,14 @@ static uint64_t swimctrl_read(void *opaque, hwaddr reg, unsigned size)
         break;
     }
 
-    trace_swim_swimctrl_read(reg, swim_reg_names[reg], size, value);
+    trace_swim_swimctrl_read(reg, ism_reg_names[reg], size, value);
     return value;
 }
 
-static const MemoryRegionOps swimctrl_mem_ops = {
-    .write = swimctrl_write,
-    .read = swimctrl_read,
-    .endianness = DEVICE_NATIVE_ENDIAN,
+static const MemoryRegionOps swimctrl_ism_ops = {
+    .write = ismctrl_write,
+    .read = ismctrl_read,
+    .endianness = DEVICE_BIG_ENDIAN,
 };
 
 static void sysbus_swim_reset(DeviceState *d)
@@ -407,13 +417,13 @@ static void sysbus_swim_reset(DeviceState *d)
 
     ctrl->mode = 0;
     ctrl->iwm_switch = 0;
-    for (i = 0; i < 8; i++) {
-        ctrl->regs[i] = 0;
-    }
     ctrl->iwm_data = 0;
     ctrl->iwm_mode = 0;
+    memset(ctrl->iwmregs, 0, 16);
+
     ctrl->swim_phase = 0;
     ctrl->swim_mode = 0;
+    memset(ctrl->ismregs, 0, 16);
     for (i = 0; i < SWIM_MAX_FD; i++) {
         fd_recalibrate(&ctrl->drives[i]);
     }
@@ -425,9 +435,12 @@ static void sysbus_swim_init(Object *obj)
     Swim *sbs = SWIM(obj);
     SWIMCtrl *swimctrl = &sbs->ctrl;
 
-    memory_region_init_io(&swimctrl->iomem, obj, &swimctrl_mem_ops, swimctrl,
-                          "swim", 0x2000);
-    sysbus_init_mmio(sbd, &swimctrl->iomem);
+    memory_region_init(&swimctrl->swim, obj, "swim", 0x2000);
+    memory_region_init_io(&swimctrl->iwm, obj, &swimctrl_iwm_ops, swimctrl,
+                          "iwm", 0x2000);
+    memory_region_init_io(&swimctrl->ism, obj, &swimctrl_ism_ops, swimctrl,
+                          "ism", 0x2000);
+    sysbus_init_mmio(sbd, &swimctrl->swim);
 }
 
 static void sysbus_swim_realize(DeviceState *dev, Error **errp)
@@ -437,6 +450,9 @@ static void sysbus_swim_realize(DeviceState *dev, Error **errp)
 
     qbus_init(&swimctrl->bus, sizeof(SWIMBus), TYPE_SWIM_BUS, dev, NULL);
     swimctrl->bus.ctrl = swimctrl;
+
+    /* Default register set is IWM */
+    memory_region_add_subregion(&swimctrl->swim, 0x0, &swimctrl->iwm);
 }
 
 static const VMStateDescription vmstate_fdrive = {
@@ -456,10 +472,11 @@ static const VMStateDescription vmstate_swim = {
         VMSTATE_INT32(mode, SWIMCtrl),
         /* IWM mode */
         VMSTATE_INT32(iwm_switch, SWIMCtrl),
-        VMSTATE_UINT16_ARRAY(regs, SWIMCtrl, 8),
+        VMSTATE_UINT8_ARRAY(iwmregs, SWIMCtrl, 16),
         VMSTATE_UINT8(iwm_data, SWIMCtrl),
         VMSTATE_UINT8(iwm_mode, SWIMCtrl),
         /* SWIM mode */
+        VMSTATE_UINT8_ARRAY(ismregs, SWIMCtrl, 16),
         VMSTATE_UINT8(swim_phase, SWIMCtrl),
         VMSTATE_UINT8(swim_mode, SWIMCtrl),
         /* Drives */
diff --git a/hw/block/trace-events b/hw/block/trace-events
index c041ec4..ea84ad6 100644
--- a/hw/block/trace-events
+++ b/hw/block/trace-events
@@ -94,6 +94,6 @@ m25p80_binding_no_bdrv(void *s) "[%p] No BDRV - binding to RAM"
 # swim.c
 swim_swimctrl_read(int reg, const char *name, unsigned size, uint64_t value) "reg=%d [%s] size=%u value=0x%"PRIx64
 swim_swimctrl_write(int reg, const char *name, unsigned size, uint64_t value) "reg=%d [%s] size=%u value=0x%"PRIx64
-swim_iwmctrl_read(int reg, unsigned size, uint64_t value) "reg=%d size=%u value=0x%"PRIx64
-swim_iwmctrl_write(int reg, unsigned size, uint64_t value) "reg=%d size=%u value=0x%"PRIx64
+swim_iwmctrl_read(int reg, const char *name, unsigned size, uint64_t value) "reg=%d [%s] size=%u value=0x%"PRIx64
+swim_iwmctrl_write(int reg, const char *name, unsigned size, uint64_t value) "reg=%d [%s] size=%u value=0x%"PRIx64
 swim_iwm_switch(void) "switch from IWM to SWIM mode"
diff --git a/include/hw/block/swim.h b/include/hw/block/swim.h
index 9b3dcb0..1bc7635 100644
--- a/include/hw/block/swim.h
+++ b/include/hw/block/swim.h
@@ -43,23 +43,18 @@ typedef struct FDrive {
 } FDrive;
 
 struct SWIMCtrl {
-    MemoryRegion iomem;
+    MemoryRegion swim;
+    MemoryRegion iwm;
+    MemoryRegion ism;
     FDrive drives[SWIM_MAX_FD];
     int mode;
     /* IWM mode */
     int iwm_switch;
-    uint16_t regs[8];
-#define IWM_PH0   0
-#define IWM_PH1   1
-#define IWM_PH2   2
-#define IWM_PH3   3
-#define IWM_MTR   4
-#define IWM_DRIVE 5
-#define IWM_Q6    6
-#define IWM_Q7    7
+    uint8_t iwmregs[16];
     uint8_t iwm_data;
     uint8_t iwm_mode;
     /* SWIM mode */
+    uint8_t ismregs[16];
     uint8_t swim_phase;
     uint8_t swim_mode;
     SWIMBus bus;