[PULL 05/11] hw/m68k: add VIA support

[Laurent Vivier <laurent@vivier.eu>]

Inside the 680x0 Macintosh, VIA (Versatile Interface Adapter) is used
to interface the keyboard, Mouse, and real-time clock. It also provides
control line for the floppy disk driver, video interface, sound circuitry
and serial interface.

This implementation is based on the MOS6522 object.

Co-developed-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Hervé Poussineau <hpoussin@reactos.org>
Message-Id: <20191026164546.30020-6-laurent@vivier.eu>
---
 default-configs/m68k-softmmu.mak |   1 +
 include/hw/misc/mac_via.h        | 108 +++++
 hw/misc/mac_via.c                | 767 +++++++++++++++++++++++++++++++
 MAINTAINERS                      |   6 +
 hw/m68k/Kconfig                  |   4 +
 hw/misc/Kconfig                  |   4 +
 hw/misc/Makefile.objs            |   1 +
 7 files changed, 891 insertions(+)
 create mode 100644 include/hw/misc/mac_via.h
 create mode 100644 hw/misc/mac_via.c

diff --git a/default-configs/m68k-softmmu.mak b/default-configs/m68k-softmmu.mak
index d67ab8b96d..6629fd2aa3 100644
--- a/default-configs/m68k-softmmu.mak
+++ b/default-configs/m68k-softmmu.mak
@@ -7,3 +7,4 @@ CONFIG_SEMIHOSTING=y
 CONFIG_AN5206=y
 CONFIG_MCF5208=y
 CONFIG_NEXTCUBE=y
+CONFIG_Q800=y
diff --git a/include/hw/misc/mac_via.h b/include/hw/misc/mac_via.h
new file mode 100644
index 0000000000..efc8ef3ce3
--- /dev/null
+++ b/include/hw/misc/mac_via.h
@@ -0,0 +1,108 @@
+/*
+ *
+ * Copyright (c) 2011-2018 Laurent Vivier
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#ifndef HW_MISC_MAC_VIA_H
+#define HW_MISC_MAC_VIA_H
+
+#include "exec/memory.h"
+#include "hw/sysbus.h"
+#include "hw/misc/mos6522.h"
+
+
+/* VIA 1 */
+#define VIA1_IRQ_ONE_SECOND_BIT 0
+#define VIA1_IRQ_VBLANK_BIT     1
+#define VIA1_IRQ_ADB_READY_BIT  2
+#define VIA1_IRQ_ADB_DATA_BIT   3
+#define VIA1_IRQ_ADB_CLOCK_BIT  4
+
+#define VIA1_IRQ_NB             8
+
+#define VIA1_IRQ_ONE_SECOND (1 << VIA1_IRQ_ONE_SECOND_BIT)
+#define VIA1_IRQ_VBLANK     (1 << VIA1_IRQ_VBLANK_BIT)
+#define VIA1_IRQ_ADB_READY  (1 << VIA1_IRQ_ADB_READY_BIT)
+#define VIA1_IRQ_ADB_DATA   (1 << VIA1_IRQ_ADB_DATA_BIT)
+#define VIA1_IRQ_ADB_CLOCK  (1 << VIA1_IRQ_ADB_CLOCK_BIT)
+
+
+#define TYPE_MOS6522_Q800_VIA1 "mos6522-q800-via1"
+#define MOS6522_Q800_VIA1(obj)  OBJECT_CHECK(MOS6522Q800VIA1State, (obj), \
+                                    TYPE_MOS6522_Q800_VIA1)
+
+typedef struct MOS6522Q800VIA1State {
+    /*< private >*/
+    MOS6522State parent_obj;
+
+    qemu_irq irqs[VIA1_IRQ_NB];
+    uint8_t last_b;
+    uint8_t PRAM[256];
+
+    /* external timers */
+    QEMUTimer *one_second_timer;
+    int64_t next_second;
+    QEMUTimer *VBL_timer;
+    int64_t next_VBL;
+} MOS6522Q800VIA1State;
+
+
+/* VIA 2 */
+#define VIA2_IRQ_SCSI_DATA_BIT  0
+#define VIA2_IRQ_SLOT_BIT       1
+#define VIA2_IRQ_UNUSED_BIT     2
+#define VIA2_IRQ_SCSI_BIT       3
+#define VIA2_IRQ_ASC_BIT        4
+
+#define VIA2_IRQ_NB             8
+
+#define VIA2_IRQ_SCSI_DATA  (1 << VIA2_IRQ_SCSI_DATA_BIT)
+#define VIA2_IRQ_SLOT       (1 << VIA2_IRQ_SLOT_BIT)
+#define VIA2_IRQ_UNUSED     (1 << VIA2_IRQ_SCSI_BIT)
+#define VIA2_IRQ_SCSI       (1 << VIA2_IRQ_UNUSED_BIT)
+#define VIA2_IRQ_ASC        (1 << VIA2_IRQ_ASC_BIT)
+
+#define TYPE_MOS6522_Q800_VIA2 "mos6522-q800-via2"
+#define MOS6522_Q800_VIA2(obj)  OBJECT_CHECK(MOS6522Q800VIA2State, (obj), \
+                                    TYPE_MOS6522_Q800_VIA2)
+
+typedef struct MOS6522Q800VIA2State {
+    /*< private >*/
+    MOS6522State parent_obj;
+} MOS6522Q800VIA2State;
+
+
+#define TYPE_MAC_VIA "mac_via"
+#define MAC_VIA(obj)   OBJECT_CHECK(MacVIAState, (obj), TYPE_MAC_VIA)
+
+typedef struct MacVIAState {
+    SysBusDevice busdev;
+
+    /* MMIO */
+    MemoryRegion mmio;
+    MemoryRegion via1mem;
+    MemoryRegion via2mem;
+
+    /* VIAs */
+    MOS6522Q800VIA1State mos6522_via1;
+    MOS6522Q800VIA2State mos6522_via2;
+
+    /* RTC */
+    uint32_t tick_offset;
+
+    uint8_t data_out;
+    int data_out_cnt;
+    uint8_t data_in;
+    uint8_t data_in_cnt;
+    uint8_t cmd;
+    int wprotect;
+    int alt;
+
+    /* ADB */
+    ADBBusState adb_bus;
+} MacVIAState;
+
+#endif
diff --git a/hw/misc/mac_via.c b/hw/misc/mac_via.c
new file mode 100644
index 0000000000..d2da8b8e60
--- /dev/null
+++ b/hw/misc/mac_via.c
@@ -0,0 +1,767 @@
+/*
+ * QEMU m68k Macintosh VIA device support
+ *
+ * Copyright (c) 2011-2018 Laurent Vivier
+ * Copyright (c) 2018 Mark Cave-Ayland
+ *
+ * Some parts from hw/misc/macio/cuda.c
+ *
+ * Copyright (c) 2004-2007 Fabrice Bellard
+ * Copyright (c) 2007 Jocelyn Mayer
+ *
+ * some parts from linux-2.6.29, arch/m68k/include/asm/mac_via.h
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+#include "migration/vmstate.h"
+#include "hw/sysbus.h"
+#include "hw/irq.h"
+#include "qemu/timer.h"
+#include "hw/misc/mac_via.h"
+#include "hw/misc/mos6522.h"
+#include "hw/input/adb.h"
+#include "sysemu/runstate.h"
+#include "qapi/error.h"
+#include "qemu/cutils.h"
+
+
+/*
+ * VIAs: There are two in every machine,
+ */
+
+#define VIA_SIZE (0x2000)
+
+/*
+ * Not all of these are true post MacII I think.
+ * CSA: probably the ones CHRP marks as 'unused' change purposes
+ * when the IWM becomes the SWIM.
+ * http://www.rs6000.ibm.com/resource/technology/chrpio/via5.mak.html
+ * ftp://ftp.austin.ibm.com/pub/technology/spec/chrp/inwork/CHRP_IORef_1.0.pdf
+ *
+ * also, http://developer.apple.com/technotes/hw/hw_09.html claims the
+ * following changes for IIfx:
+ * VIA1A_vSccWrReq not available and that VIA1A_vSync has moved to an IOP.
+ * Also, "All of the functionality of VIA2 has been moved to other chips".
+ */
+
+#define VIA1A_vSccWrReq 0x80   /*
+                                * SCC write. (input)
+                                * [CHRP] SCC WREQ: Reflects the state of the
+                                * Wait/Request pins from the SCC.
+                                * [Macintosh Family Hardware]
+                                * as CHRP on SE/30,II,IIx,IIcx,IIci.
+                                * on IIfx, "0 means an active request"
+                                */
+#define VIA1A_vRev8     0x40   /*
+                                * Revision 8 board ???
+                                * [CHRP] En WaitReqB: Lets the WaitReq_L
+                                * signal from port B of the SCC appear on
+                                * the PA7 input pin. Output.
+                                * [Macintosh Family] On the SE/30, this
+                                * is the bit to flip screen buffers.
+                                * 0=alternate, 1=main.
+                                * on II,IIx,IIcx,IIci,IIfx this is a bit
+                                * for Rev ID. 0=II,IIx, 1=IIcx,IIci,IIfx
+                                */
+#define VIA1A_vHeadSel  0x20   /*
+                                * Head select for IWM.
+                                * [CHRP] unused.
+                                * [Macintosh Family] "Floppy disk
+                                * state-control line SEL" on all but IIfx
+                                */
+#define VIA1A_vOverlay  0x10   /*
+                                * [Macintosh Family] On SE/30,II,IIx,IIcx
+                                * this bit enables the "Overlay" address
+                                * map in the address decoders as it is on
+                                * reset for mapping the ROM over the reset
+                                * vector. 1=use overlay map.
+                                * On the IIci,IIfx it is another bit of the
+                                * CPU ID: 0=normal IIci, 1=IIci with parity
+                                * feature or IIfx.
+                                * [CHRP] En WaitReqA: Lets the WaitReq_L
+                                * signal from port A of the SCC appear
+                                * on the PA7 input pin (CHRP). Output.
+                                * [MkLinux] "Drive Select"
+                                *  (with 0x20 being 'disk head select')
+                                */
+#define VIA1A_vSync     0x08   /*
+                                * [CHRP] Sync Modem: modem clock select:
+                                * 1: select the external serial clock to
+                                *    drive the SCC's /RTxCA pin.
+                                * 0: Select the 3.6864MHz clock to drive
+                                *    the SCC cell.
+                                * [Macintosh Family] Correct on all but IIfx
+                                */
+
+/*
+ * Macintosh Family Hardware sez: bits 0-2 of VIA1A are volume control
+ * on Macs which had the PWM sound hardware.  Reserved on newer models.
+ * On IIci,IIfx, bits 1-2 are the rest of the CPU ID:
+ * bit 2: 1=IIci, 0=IIfx
+ * bit 1: 1 on both IIci and IIfx.
+ * MkLinux sez bit 0 is 'burnin flag' in this case.
+ * CHRP sez: VIA1A bits 0-2 and 5 are 'unused': if programmed as
+ * inputs, these bits will read 0.
+ */
+#define VIA1A_vVolume   0x07    /* Audio volume mask for PWM */
+#define VIA1A_CPUID0    0x02    /* CPU id bit 0 on RBV, others */
+#define VIA1A_CPUID1    0x04    /* CPU id bit 0 on RBV, others */
+#define VIA1A_CPUID2    0x10    /* CPU id bit 0 on RBV, others */
+#define VIA1A_CPUID3    0x40    /* CPU id bit 0 on RBV, others */
+
+/*
+ * Info on VIA1B is from Macintosh Family Hardware & MkLinux.
+ * CHRP offers no info.
+ */
+#define VIA1B_vSound   0x80    /*
+                                * Sound enable (for compatibility with
+                                * PWM hardware) 0=enabled.
+                                * Also, on IIci w/parity, shows parity error
+                                * 0=error, 1=OK.
+                                */
+#define VIA1B_vMystery 0x40    /*
+                                * On IIci, parity enable. 0=enabled,1=disabled
+                                * On SE/30, vertical sync interrupt enable.
+                                * 0=enabled. This vSync interrupt shows up
+                                * as a slot $E interrupt.
+                                */
+#define VIA1B_vADBS2   0x20    /* ADB state input bit 1 (unused on IIfx) */
+#define VIA1B_vADBS1   0x10    /* ADB state input bit 0 (unused on IIfx) */
+#define VIA1B_vADBInt  0x08    /* ADB interrupt 0=interrupt (unused on IIfx)*/
+#define VIA1B_vRTCEnb  0x04    /* Enable Real time clock. 0=enabled. */
+#define VIA1B_vRTCClk  0x02    /* Real time clock serial-clock line. */
+#define VIA1B_vRTCData 0x01    /* Real time clock serial-data line. */
+
+/*
+ *    VIA2 A register is the interrupt lines raised off the nubus
+ *    slots.
+ *      The below info is from 'Macintosh Family Hardware.'
+ *      MkLinux calls the 'IIci internal video IRQ' below the 'RBV slot 0 irq.'
+ *      It also notes that the slot $9 IRQ is the 'Ethernet IRQ' and
+ *      defines the 'Video IRQ' as 0x40 for the 'EVR' VIA work-alike.
+ *      Perhaps OSS uses vRAM1 and vRAM2 for ADB.
+ */
+
+#define VIA2A_vRAM1    0x80    /* RAM size bit 1 (IIci: reserved) */
+#define VIA2A_vRAM0    0x40    /* RAM size bit 0 (IIci: internal video IRQ) */
+#define VIA2A_vIRQE    0x20    /* IRQ from slot $E */
+#define VIA2A_vIRQD    0x10    /* IRQ from slot $D */
+#define VIA2A_vIRQC    0x08    /* IRQ from slot $C */
+#define VIA2A_vIRQB    0x04    /* IRQ from slot $B */
+#define VIA2A_vIRQA    0x02    /* IRQ from slot $A */
+#define VIA2A_vIRQ9    0x01    /* IRQ from slot $9 */
+
+/*
+ * RAM size bits decoded as follows:
+ * bit1 bit0  size of ICs in bank A
+ *  0    0    256 kbit
+ *  0    1    1 Mbit
+ *  1    0    4 Mbit
+ *  1    1   16 Mbit
+ */
+
+/*
+ *    Register B has the fun stuff in it
+ */
+
+#define VIA2B_vVBL    0x80    /*
+                               * VBL output to VIA1 (60.15Hz) driven by
+                               * timer T1.
+                               * on IIci, parity test: 0=test mode.
+                               * [MkLinux] RBV_PARODD: 1=odd,0=even.
+                               */
+#define VIA2B_vSndJck 0x40    /*
+                               * External sound jack status.
+                               * 0=plug is inserted.  On SE/30, always 0
+                               */
+#define VIA2B_vTfr0   0x20    /* Transfer mode bit 0 ack from NuBus */
+#define VIA2B_vTfr1   0x10    /* Transfer mode bit 1 ack from NuBus */
+#define VIA2B_vMode32 0x08    /*
+                               * 24/32bit switch - doubles as cache flush
+                               * on II, AMU/PMMU control.
+                               *   if AMU, 0=24bit to 32bit translation
+                               *   if PMMU, 1=PMMU is accessing page table.
+                               * on SE/30 tied low.
+                               * on IIx,IIcx,IIfx, unused.
+                               * on IIci/RBV, cache control. 0=flush cache.
+                               */
+#define VIA2B_vPower  0x04   /*
+                              * Power off, 0=shut off power.
+                              * on SE/30 this signal sent to PDS card.
+                              */
+#define VIA2B_vBusLk  0x02   /*
+                              * Lock NuBus transactions, 0=locked.
+                              * on SE/30 sent to PDS card.
+                              */
+#define VIA2B_vCDis   0x01   /*
+                              * Cache control. On IIci, 1=disable cache card
+                              * on others, 0=disable processor's instruction
+                              * and data caches.
+                              */
+
+/* interrupt flags */
+
+#define IRQ_SET         0x80
+
+/* common */
+
+#define VIA_IRQ_TIMER1      0x40
+#define VIA_IRQ_TIMER2      0x20
+
+/*
+ * Apple sez: http://developer.apple.com/technotes/ov/ov_04.html
+ * Another example of a valid function that has no ROM support is the use
+ * of the alternate video page for page-flipping animation. Since there
+ * is no ROM call to flip pages, it is necessary to go play with the
+ * right bit in the VIA chip (6522 Versatile Interface Adapter).
+ * [CSA: don't know which one this is, but it's one of 'em!]
+ */
+
+/*
+ *    6522 registers - see databook.
+ * CSA: Assignments for VIA1 confirmed from CHRP spec.
+ */
+
+/* partial address decode.  0xYYXX : XX part for RBV, YY part for VIA */
+/* Note: 15 VIA regs, 8 RBV regs */
+
+#define vBufB    0x0000  /* [VIA/RBV]  Register B */
+#define vBufAH   0x0200  /* [VIA only] Buffer A, with handshake. DON'T USE! */
+#define vDirB    0x0400  /* [VIA only] Data Direction Register B. */
+#define vDirA    0x0600  /* [VIA only] Data Direction Register A. */
+#define vT1CL    0x0800  /* [VIA only] Timer one counter low. */
+#define vT1CH    0x0a00  /* [VIA only] Timer one counter high. */
+#define vT1LL    0x0c00  /* [VIA only] Timer one latches low. */
+#define vT1LH    0x0e00  /* [VIA only] Timer one latches high. */
+#define vT2CL    0x1000  /* [VIA only] Timer two counter low. */
+#define vT2CH    0x1200  /* [VIA only] Timer two counter high. */
+#define vSR      0x1400  /* [VIA only] Shift register. */
+#define vACR     0x1600  /* [VIA only] Auxilary control register. */
+#define vPCR     0x1800  /* [VIA only] Peripheral control register. */
+                         /*
+                          *           CHRP sez never ever to *write* this.
+                          *            Mac family says never to *change* this.
+                          * In fact we need to initialize it once at start.
+                          */
+#define vIFR     0x1a00  /* [VIA/RBV]  Interrupt flag register. */
+#define vIER     0x1c00  /* [VIA/RBV]  Interrupt enable register. */
+#define vBufA    0x1e00  /* [VIA/RBV] register A (no handshake) */
+
+/* from linux 2.6 drivers/macintosh/via-macii.c */
+
+/* Bits in ACR */
+
+#define VIA1ACR_vShiftCtrl         0x1c        /* Shift register control bits */
+#define VIA1ACR_vShiftExtClk       0x0c        /* Shift on external clock */
+#define VIA1ACR_vShiftOut          0x10        /* Shift out if 1 */
+
+/*
+ * Apple Macintosh Family Hardware Refenece
+ * Table 19-10 ADB transaction states
+ */
+
+#define VIA1B_vADB_StateMask    (VIA1B_vADBS1 | VIA1B_vADBS2)
+#define VIA1B_vADB_StateShift   4
+
+#define VIA_TIMER_FREQ (783360)
+
+/* VIA returns time offset from Jan 1, 1904, not 1970 */
+#define RTC_OFFSET 2082844800
+
+static void via1_VBL_update(MOS6522Q800VIA1State *v1s)
+{
+    MOS6522State *s = MOS6522(v1s);
+
+    /* 60 Hz irq */
+    v1s->next_VBL = (qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + 16630) /
+                    16630 * 16630;
+
+    if (s->ier & VIA1_IRQ_VBLANK) {
+        timer_mod(v1s->VBL_timer, v1s->next_VBL);
+    } else {
+        timer_del(v1s->VBL_timer);
+    }
+}
+
+static void via1_one_second_update(MOS6522Q800VIA1State *v1s)
+{
+    MOS6522State *s = MOS6522(v1s);
+
+    v1s->next_second = (qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 1000) /
+                       1000 * 1000;
+    if (s->ier & VIA1_IRQ_ONE_SECOND) {
+        timer_mod(v1s->one_second_timer, v1s->next_second);
+    } else {
+        timer_del(v1s->one_second_timer);
+    }
+}
+
+static void via1_VBL(void *opaque)
+{
+    MOS6522Q800VIA1State *v1s = opaque;
+    MOS6522State *s = MOS6522(v1s);
+    MOS6522DeviceClass *mdc = MOS6522_DEVICE_GET_CLASS(s);
+
+    s->ifr |= VIA1_IRQ_VBLANK;
+    mdc->update_irq(s);
+
+    via1_VBL_update(v1s);
+}
+
+static void via1_one_second(void *opaque)
+{
+    MOS6522Q800VIA1State *v1s = opaque;
+    MOS6522State *s = MOS6522(v1s);
+    MOS6522DeviceClass *mdc = MOS6522_DEVICE_GET_CLASS(s);
+
+    s->ifr |= VIA1_IRQ_ONE_SECOND;
+    mdc->update_irq(s);
+
+    via1_one_second_update(v1s);
+}
+
+static void via1_irq_request(void *opaque, int irq, int level)
+{
+    MOS6522Q800VIA1State *v1s = opaque;
+    MOS6522State *s = MOS6522(v1s);
+    MOS6522DeviceClass *mdc = MOS6522_DEVICE_GET_CLASS(s);
+
+    if (level) {
+        s->ifr |= 1 << irq;
+    } else {
+        s->ifr &= ~(1 << irq);
+    }
+
+    mdc->update_irq(s);
+}
+
+static void via2_irq_request(void *opaque, int irq, int level)
+{
+    MOS6522Q800VIA2State *v2s = opaque;
+    MOS6522State *s = MOS6522(v2s);
+    MOS6522DeviceClass *mdc = MOS6522_DEVICE_GET_CLASS(s);
+
+    if (level) {
+        s->ifr |= 1 << irq;
+    } else {
+        s->ifr &= ~(1 << irq);
+    }
+
+    mdc->update_irq(s);
+}
+
+static void via1_rtc_update(MacVIAState *m)
+{
+    MOS6522Q800VIA1State *v1s = &m->mos6522_via1;
+    MOS6522State *s = MOS6522(v1s);
+
+    if (s->b & VIA1B_vRTCEnb) {
+        return;
+    }
+
+    if (s->dirb & VIA1B_vRTCData) {
+        /* send bits to the RTC */
+        if (!(v1s->last_b & VIA1B_vRTCClk) && (s->b & VIA1B_vRTCClk)) {
+            m->data_out <<= 1;
+            m->data_out |= s->b & VIA1B_vRTCData;
+            m->data_out_cnt++;
+        }
+    } else {
+        /* receive bits from the RTC */
+        if ((v1s->last_b & VIA1B_vRTCClk) &&
+            !(s->b & VIA1B_vRTCClk) &&
+            m->data_in_cnt) {
+            s->b = (s->b & ~VIA1B_vRTCData) |
+                   ((m->data_in >> 7) & VIA1B_vRTCData);
+            m->data_in <<= 1;
+            m->data_in_cnt--;
+        }
+    }
+
+    if (m->data_out_cnt == 8) {
+        m->data_out_cnt = 0;
+
+        if (m->cmd == 0) {
+            if (m->data_out & 0x80) {
+                /* this is a read command */
+                uint32_t time = m->tick_offset +
+                               (qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) /
+                               NANOSECONDS_PER_SECOND);
+                if (m->data_out == 0x81) {        /* seconds register 0 */
+                    m->data_in = time & 0xff;
+                    m->data_in_cnt = 8;
+                } else if (m->data_out == 0x85) { /* seconds register 1 */
+                    m->data_in = (time >> 8) & 0xff;
+                    m->data_in_cnt = 8;
+                } else if (m->data_out == 0x89) { /* seconds register 2 */
+                    m->data_in = (time >> 16) & 0xff;
+                    m->data_in_cnt = 8;
+                } else if (m->data_out == 0x8d) { /* seconds register 3 */
+                    m->data_in = (time >> 24) & 0xff;
+                    m->data_in_cnt = 8;
+                } else if ((m->data_out & 0xf3) == 0xa1) {
+                    /* PRAM address 0x10 -> 0x13 */
+                    int addr = (m->data_out >> 2) & 0x03;
+                    m->data_in = v1s->PRAM[addr];
+                    m->data_in_cnt = 8;
+                } else if ((m->data_out & 0xf3) == 0xa1) {
+                    /* PRAM address 0x00 -> 0x0f */
+                    int addr = (m->data_out >> 2) & 0x0f;
+                    m->data_in = v1s->PRAM[addr];
+                    m->data_in_cnt = 8;
+                } else if ((m->data_out & 0xf8) == 0xb8) {
+                    /* extended memory designator and sector number */
+                    m->cmd = m->data_out;
+                }
+            } else {
+                /* this is a write command */
+                m->cmd = m->data_out;
+            }
+        } else {
+            if (m->cmd & 0x80) {
+                if ((m->cmd & 0xf8) == 0xb8) {
+                    /* extended memory designator and sector number */
+                    int sector = m->cmd & 0x07;
+                    int addr = (m->data_out >> 2) & 0x1f;
+
+                    m->data_in = v1s->PRAM[sector * 8 + addr];
+                    m->data_in_cnt = 8;
+                }
+            } else if (!m->wprotect) {
+                /* this is a write command */
+                if (m->alt != 0) {
+                    /* extended memory designator and sector number */
+                    int sector = m->cmd & 0x07;
+                    int addr = (m->alt >> 2) & 0x1f;
+
+                    v1s->PRAM[sector * 8 + addr] = m->data_out;
+
+                    m->alt = 0;
+                } else if (m->cmd == 0x01) { /* seconds register 0 */
+                    /* FIXME */
+                } else if (m->cmd == 0x05) { /* seconds register 1 */
+                    /* FIXME */
+                } else if (m->cmd == 0x09) { /* seconds register 2 */
+                    /* FIXME */
+                } else if (m->cmd == 0x0d) { /* seconds register 3 */
+                    /* FIXME */
+                } else if (m->cmd == 0x31) {
+                    /* Test Register */
+                } else if (m->cmd == 0x35) {
+                    /* Write Protect register */
+                    m->wprotect = m->data_out & 1;
+                } else if ((m->cmd & 0xf3) == 0xa1) {
+                    /* PRAM address 0x10 -> 0x13 */
+                    int addr = (m->cmd >> 2) & 0x03;
+                    v1s->PRAM[addr] = m->data_out;
+                } else if ((m->cmd & 0xf3) == 0xa1) {
+                    /* PRAM address 0x00 -> 0x0f */
+                    int addr = (m->cmd >> 2) & 0x0f;
+                    v1s->PRAM[addr] = m->data_out;
+                } else if ((m->cmd & 0xf8) == 0xb8) {
+                    /* extended memory designator and sector number */
+                    m->alt = m->cmd;
+                }
+            }
+        }
+        m->data_out = 0;
+    }
+}
+
+static uint64_t mos6522_q800_via1_read(void *opaque, hwaddr addr, unsigned size)
+{
+    MOS6522Q800VIA1State *s = MOS6522_Q800_VIA1(opaque);
+    MOS6522State *ms = MOS6522(s);
+    int64_t now = qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL);
+
+    /*
+     * If IRQs are disabled, timers are disabled, but we need to update
+     * VIA1_IRQ_VBLANK and VIA1_IRQ_ONE_SECOND bits in the IFR
+     */
+
+    if (now >= s->next_VBL) {
+        ms->ifr |= VIA1_IRQ_VBLANK;
+        via1_VBL_update(s);
+    }
+    if (now >= s->next_second) {
+        ms->ifr |= VIA1_IRQ_ONE_SECOND;
+        via1_one_second_update(s);
+    }
+
+    addr = (addr >> 9) & 0xf;
+    return mos6522_read(ms, addr, size);
+}
+
+static void mos6522_q800_via1_write(void *opaque, hwaddr addr, uint64_t val,
+                                    unsigned size)
+{
+    MOS6522Q800VIA1State *v1s = MOS6522_Q800_VIA1(opaque);
+    MOS6522State *ms = MOS6522(v1s);
+
+    addr = (addr >> 9) & 0xf;
+    mos6522_write(ms, addr, val, size);
+
+    via1_one_second_update(v1s);
+    via1_VBL_update(v1s);
+}
+
+static const MemoryRegionOps mos6522_q800_via1_ops = {
+    .read = mos6522_q800_via1_read,
+    .write = mos6522_q800_via1_write,
+    .endianness = DEVICE_BIG_ENDIAN,
+    .valid = {
+        .min_access_size = 1,
+        .max_access_size = 1,
+    },
+};
+
+static uint64_t mos6522_q800_via2_read(void *opaque, hwaddr addr, unsigned size)
+{
+    MOS6522Q800VIA2State *s = MOS6522_Q800_VIA2(opaque);
+    MOS6522State *ms = MOS6522(s);
+
+    addr = (addr >> 9) & 0xf;
+    return mos6522_read(ms, addr, size);
+}
+
+static void mos6522_q800_via2_write(void *opaque, hwaddr addr, uint64_t val,
+                                    unsigned size)
+{
+    MOS6522Q800VIA2State *s = MOS6522_Q800_VIA2(opaque);
+    MOS6522State *ms = MOS6522(s);
+
+    addr = (addr >> 9) & 0xf;
+    mos6522_write(ms, addr, val, size);
+}
+
+static const MemoryRegionOps mos6522_q800_via2_ops = {
+    .read = mos6522_q800_via2_read,
+    .write = mos6522_q800_via2_write,
+    .endianness = DEVICE_BIG_ENDIAN,
+    .valid = {
+        .min_access_size = 1,
+        .max_access_size = 1,
+    },
+};
+
+static void mac_via_reset(DeviceState *dev)
+{
+    MacVIAState *m = MAC_VIA(dev);
+    MOS6522Q800VIA1State *v1s = &m->mos6522_via1;
+
+    timer_del(v1s->VBL_timer);
+    v1s->next_VBL = 0;
+    timer_del(v1s->one_second_timer);
+    v1s->next_second = 0;
+}
+
+static void mac_via_realize(DeviceState *dev, Error **errp)
+{
+    MacVIAState *m = MAC_VIA(dev);
+    MOS6522State *ms;
+    struct tm tm;
+
+    /* Init VIAs 1 and 2 */
+    sysbus_init_child_obj(OBJECT(dev), "via1", &m->mos6522_via1,
+                          sizeof(m->mos6522_via1), TYPE_MOS6522_Q800_VIA1);
+
+    sysbus_init_child_obj(OBJECT(dev), "via2", &m->mos6522_via2,
+                          sizeof(m->mos6522_via2), TYPE_MOS6522_Q800_VIA2);
+
+    /* Pass through mos6522 output IRQs */
+    ms = MOS6522(&m->mos6522_via1);
+    object_property_add_alias(OBJECT(dev), "irq[0]", OBJECT(ms),
+                              SYSBUS_DEVICE_GPIO_IRQ "[0]", &error_abort);
+    ms = MOS6522(&m->mos6522_via2);
+    object_property_add_alias(OBJECT(dev), "irq[1]", OBJECT(ms),
+                              SYSBUS_DEVICE_GPIO_IRQ "[0]", &error_abort);
+
+    /* Pass through mos6522 input IRQs */
+    qdev_pass_gpios(DEVICE(&m->mos6522_via1), dev, "via1-irq");
+    qdev_pass_gpios(DEVICE(&m->mos6522_via2), dev, "via2-irq");
+
+    /* VIA 1 */
+    m->mos6522_via1.one_second_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL,
+                                                     via1_one_second,
+                                                     &m->mos6522_via1);
+    m->mos6522_via1.VBL_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, via1_VBL,
+                                              &m->mos6522_via1);
+
+    qemu_get_timedate(&tm, 0);
+    m->tick_offset = (uint32_t)mktimegm(&tm) + RTC_OFFSET;
+}
+
+static void mac_via_init(Object *obj)
+{
+    SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
+    MacVIAState *m = MAC_VIA(obj);
+
+    /* MMIO */
+    memory_region_init(&m->mmio, obj, "mac-via", 2 * VIA_SIZE);
+    sysbus_init_mmio(sbd, &m->mmio);
+
+    memory_region_init_io(&m->via1mem, obj, &mos6522_q800_via1_ops,
+                          &m->mos6522_via1, "via1", VIA_SIZE);
+    memory_region_add_subregion(&m->mmio, 0x0, &m->via1mem);
+
+    memory_region_init_io(&m->via2mem, obj, &mos6522_q800_via2_ops,
+                          &m->mos6522_via2, "via2", VIA_SIZE);
+    memory_region_add_subregion(&m->mmio, VIA_SIZE, &m->via2mem);
+
+    /* ADB */
+    qbus_create_inplace((BusState *)&m->adb_bus, sizeof(m->adb_bus),
+                        TYPE_ADB_BUS, DEVICE(obj), "adb.0");
+}
+
+static const VMStateDescription vmstate_mac_via = {
+    .name = "mac-via",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        /* VIAs */
+        VMSTATE_STRUCT(mos6522_via1.parent_obj, MacVIAState, 0, vmstate_mos6522,
+                       MOS6522State),
+        VMSTATE_UINT8(mos6522_via1.last_b, MacVIAState),
+        VMSTATE_BUFFER(mos6522_via1.PRAM, MacVIAState),
+        VMSTATE_TIMER_PTR(mos6522_via1.one_second_timer, MacVIAState),
+        VMSTATE_INT64(mos6522_via1.next_second, MacVIAState),
+        VMSTATE_TIMER_PTR(mos6522_via1.VBL_timer, MacVIAState),
+        VMSTATE_INT64(mos6522_via1.next_VBL, MacVIAState),
+        VMSTATE_STRUCT(mos6522_via2.parent_obj, MacVIAState, 0, vmstate_mos6522,
+                       MOS6522State),
+        /* RTC */
+        VMSTATE_UINT32(tick_offset, MacVIAState),
+        VMSTATE_UINT8(data_out, MacVIAState),
+        VMSTATE_INT32(data_out_cnt, MacVIAState),
+        VMSTATE_UINT8(data_in, MacVIAState),
+        VMSTATE_UINT8(data_in_cnt, MacVIAState),
+        VMSTATE_UINT8(cmd, MacVIAState),
+        VMSTATE_INT32(wprotect, MacVIAState),
+        VMSTATE_INT32(alt, MacVIAState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static void mac_via_class_init(ObjectClass *oc, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(oc);
+
+    dc->realize = mac_via_realize;
+    dc->reset = mac_via_reset;
+    dc->vmsd = &vmstate_mac_via;
+}
+
+static TypeInfo mac_via_info = {
+    .name = TYPE_MAC_VIA,
+    .parent = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(MacVIAState),
+    .instance_init = mac_via_init,
+    .class_init = mac_via_class_init,
+};
+
+/* VIA 1 */
+static void mos6522_q800_via1_portB_write(MOS6522State *s)
+{
+    MOS6522Q800VIA1State *v1s = container_of(s, MOS6522Q800VIA1State,
+                                             parent_obj);
+    MacVIAState *m = container_of(v1s, MacVIAState, mos6522_via1);
+
+    via1_rtc_update(m);
+
+    v1s->last_b = s->b;
+}
+
+static void mos6522_q800_via1_reset(DeviceState *dev)
+{
+    MOS6522State *ms = MOS6522(dev);
+    MOS6522DeviceClass *mdc = MOS6522_DEVICE_GET_CLASS(ms);
+
+    mdc->parent_reset(dev);
+
+    ms->timers[0].frequency = VIA_TIMER_FREQ;
+    ms->timers[1].frequency = VIA_TIMER_FREQ;
+
+    ms->b = VIA1B_vADB_StateMask | VIA1B_vADBInt | VIA1B_vRTCEnb;
+}
+
+static void mos6522_q800_via1_init(Object *obj)
+{
+    qdev_init_gpio_in_named(DEVICE(obj), via1_irq_request, "via1-irq",
+                            VIA1_IRQ_NB);
+}
+
+static void mos6522_q800_via1_class_init(ObjectClass *oc, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(oc);
+    MOS6522DeviceClass *mdc = MOS6522_DEVICE_CLASS(oc);
+
+    dc->reset = mos6522_q800_via1_reset;
+    mdc->portB_write = mos6522_q800_via1_portB_write;
+}
+
+static const TypeInfo mos6522_q800_via1_type_info = {
+    .name = TYPE_MOS6522_Q800_VIA1,
+    .parent = TYPE_MOS6522,
+    .instance_size = sizeof(MOS6522Q800VIA1State),
+    .instance_init = mos6522_q800_via1_init,
+    .class_init = mos6522_q800_via1_class_init,
+};
+
+/* VIA 2 */
+static void mos6522_q800_via2_portB_write(MOS6522State *s)
+{
+    if (s->dirb & VIA2B_vPower && (s->b & VIA2B_vPower) == 0) {
+        /* shutdown */
+        qemu_system_shutdown_request(SHUTDOWN_CAUSE_GUEST_SHUTDOWN);
+    }
+}
+
+static void mos6522_q800_via2_reset(DeviceState *dev)
+{
+    MOS6522State *ms = MOS6522(dev);
+    MOS6522DeviceClass *mdc = MOS6522_DEVICE_GET_CLASS(ms);
+
+    mdc->parent_reset(dev);
+
+    ms->timers[0].frequency = VIA_TIMER_FREQ;
+    ms->timers[1].frequency = VIA_TIMER_FREQ;
+
+    ms->dirb = 0;
+    ms->b = 0;
+}
+
+static void mos6522_q800_via2_init(Object *obj)
+{
+    qdev_init_gpio_in_named(DEVICE(obj), via2_irq_request, "via2-irq",
+                            VIA2_IRQ_NB);
+}
+
+static void mos6522_q800_via2_class_init(ObjectClass *oc, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(oc);
+    MOS6522DeviceClass *mdc = MOS6522_DEVICE_CLASS(oc);
+
+    dc->reset = mos6522_q800_via2_reset;
+    mdc->portB_write = mos6522_q800_via2_portB_write;
+}
+
+static const TypeInfo mos6522_q800_via2_type_info = {
+    .name = TYPE_MOS6522_Q800_VIA2,
+    .parent = TYPE_MOS6522,
+    .instance_size = sizeof(MOS6522Q800VIA2State),
+    .instance_init = mos6522_q800_via2_init,
+    .class_init = mos6522_q800_via2_class_init,
+};
+
+static void mac_via_register_types(void)
+{
+    type_register_static(&mos6522_q800_via1_type_info);
+    type_register_static(&mos6522_q800_via2_type_info);
+    type_register_static(&mac_via_info);
+}
+
+type_init(mac_via_register_types);
diff --git a/MAINTAINERS b/MAINTAINERS
index ed41d7d1b6..3ce8d10b58 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -917,6 +917,12 @@ F: hw/m68k/next-*.c
 F: hw/display/next-fb.c
 F: include/hw/m68k/next-cube.h
 
+q800
+M: Laurent Vivier <laurent@vivier.eu>
+S: Maintained
+F: hw/misc/mac_via.c
+F: include/hw/misc/mac_via.h
+
 MicroBlaze Machines
 -------------------
 petalogix_s3adsp1800
diff --git a/hw/m68k/Kconfig b/hw/m68k/Kconfig
index a74fac5abd..22a357609c 100644
--- a/hw/m68k/Kconfig
+++ b/hw/m68k/Kconfig
@@ -12,3 +12,7 @@ config NEXTCUBE
     bool
     select FRAMEBUFFER
     select ESCC
+
+config Q800
+    bool
+    select MAC_VIA
diff --git a/hw/misc/Kconfig b/hw/misc/Kconfig
index 51754bb47c..18a5dc9c09 100644
--- a/hw/misc/Kconfig
+++ b/hw/misc/Kconfig
@@ -120,4 +120,8 @@ config AUX
 config UNIMP
     bool
 
+config MAC_VIA
+    bool
+    select MOS6522
+
 source macio/Kconfig
diff --git a/hw/misc/Makefile.objs b/hw/misc/Makefile.objs
index c89f3816a5..ba898a5781 100644
--- a/hw/misc/Makefile.objs
+++ b/hw/misc/Makefile.objs
@@ -79,5 +79,6 @@ common-obj-$(CONFIG_ASPEED_SOC) += aspeed_xdma.o
 common-obj-$(CONFIG_ASPEED_SOC) += aspeed_scu.o aspeed_sdmc.o
 common-obj-$(CONFIG_MSF2) += msf2-sysreg.o
 common-obj-$(CONFIG_NRF51_SOC) += nrf51_rng.o
+obj-$(CONFIG_MAC_VIA) += mac_via.o
 
 common-obj-$(CONFIG_GRLIB) += grlib_ahb_apb_pnp.o
-- 
2.21.0