lm32: add Milkymist System Controller support

This patch adds support for Milkymist's System Controller core. The model
has the following features:
 - support for shutting down and restarting the board
 - provide two timers and GPIO
 - provide registers for system identification and reading the boards
   capabilities

Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>

1 files changed, 330 insertions, 0 deletions

diff --git a/hw/milkymist-sysctl.c b/hw/milkymist-sysctl.c
new file mode 100644
index 0000000..eaea543
--- /dev/null
+++ b/hw/milkymist-sysctl.c
@@ -0,0 +1,330 @@
+/*
+ *  QEMU model of the Milkymist System Controller.
+ *
+ *  Copyright (c) 2010 Michael Walle <michael@walle.cc>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ *
+ *
+ * Specification available at:
+ *   http://www.milkymist.org/socdoc/sysctl.pdf
+ */
+
+#include "hw.h"
+#include "sysbus.h"
+#include "sysemu.h"
+#include "trace.h"
+#include "qemu-timer.h"
+#include "qemu-error.h"
+
+enum {
+    CTRL_ENABLE      = (1<<0),
+    CTRL_AUTORESTART = (1<<1),
+};
+
+enum {
+    ICAP_READY       = (1<<0),
+};
+
+enum {
+    R_GPIO_IN = 0,
+    R_GPIO_OUT,
+    R_GPIO_INTEN,
+    R_RESERVED0,
+    R_TIMER0_CONTROL,
+    R_TIMER0_COMPARE,
+    R_TIMER0_COUNTER,
+    R_RESERVED1,
+    R_TIMER1_CONTROL,
+    R_TIMER1_COMPARE,
+    R_TIMER1_COUNTER,
+    R_RESERVED2,
+    R_RESERVED3,
+    R_ICAP,
+    R_CAPABILITIES,
+    R_SYSTEM_ID,
+    R_MAX
+};
+
+struct MilkymistSysctlState {
+    SysBusDevice busdev;
+
+    QEMUBH *bh0;
+    QEMUBH *bh1;
+    ptimer_state *ptimer0;
+    ptimer_state *ptimer1;
+
+    uint32_t freq_hz;
+    uint32_t capabilities;
+    uint32_t systemid;
+    uint32_t strappings;
+
+    uint32_t regs[R_MAX];
+
+    qemu_irq gpio_irq;
+    qemu_irq timer0_irq;
+    qemu_irq timer1_irq;
+};
+typedef struct MilkymistSysctlState MilkymistSysctlState;
+
+static void sysctl_icap_write(MilkymistSysctlState *s, uint32_t value)
+{
+    trace_milkymist_sysctl_icap_write(value);
+    switch (value & 0xffff) {
+    case 0x000e:
+        qemu_system_shutdown_request();
+        break;
+    }
+}
+
+static uint32_t sysctl_read(void *opaque, target_phys_addr_t addr)
+{
+    MilkymistSysctlState *s = opaque;
+    uint32_t r = 0;
+
+    addr >>= 2;
+    switch (addr) {
+    case R_TIMER0_COUNTER:
+        r = (uint32_t)ptimer_get_count(s->ptimer0);
+        /* milkymist timer counts up */
+        r = s->regs[R_TIMER0_COMPARE] - r;
+        break;
+    case R_TIMER1_COUNTER:
+        r = (uint32_t)ptimer_get_count(s->ptimer1);
+        /* milkymist timer counts up */
+        r = s->regs[R_TIMER1_COMPARE] - r;
+        break;
+    case R_GPIO_IN:
+    case R_GPIO_OUT:
+    case R_GPIO_INTEN:
+    case R_TIMER0_CONTROL:
+    case R_TIMER0_COMPARE:
+    case R_TIMER1_CONTROL:
+    case R_TIMER1_COMPARE:
+    case R_ICAP:
+    case R_CAPABILITIES:
+    case R_SYSTEM_ID:
+        r = s->regs[addr];
+        break;
+
+    default:
+        error_report("milkymist_sysctl: read access to unkown register 0x"
+                TARGET_FMT_plx, addr << 2);
+        break;
+    }
+
+    trace_milkymist_sysctl_memory_read(addr << 2, r);
+
+    return r;
+}
+
+static void sysctl_write(void *opaque, target_phys_addr_t addr, uint32_t value)
+{
+    MilkymistSysctlState *s = opaque;
+
+    trace_milkymist_sysctl_memory_write(addr, value);
+
+    addr >>= 2;
+    switch (addr) {
+    case R_GPIO_OUT:
+    case R_GPIO_INTEN:
+    case R_TIMER0_COUNTER:
+        if (value > s->regs[R_TIMER0_COUNTER]) {
+            value = s->regs[R_TIMER0_COUNTER];
+            error_report("milkymist_sysctl: timer0: trying to write a "
+                    "value greater than the limit. Clipping.");
+        }
+        /* milkymist timer counts up */
+        value = s->regs[R_TIMER0_COUNTER] - value;
+        ptimer_set_count(s->ptimer0, value);
+        break;
+    case R_TIMER1_COUNTER:
+        if (value > s->regs[R_TIMER1_COUNTER]) {
+            value = s->regs[R_TIMER1_COUNTER];
+            error_report("milkymist_sysctl: timer1: trying to write a "
+                    "value greater than the limit. Clipping.");
+        }
+        /* milkymist timer counts up */
+        value = s->regs[R_TIMER1_COUNTER] - value;
+        ptimer_set_count(s->ptimer1, value);
+        break;
+    case R_TIMER0_COMPARE:
+        ptimer_set_limit(s->ptimer0, value, 0);
+        s->regs[addr] = value;
+        break;
+    case R_TIMER1_COMPARE:
+        ptimer_set_limit(s->ptimer1, value, 0);
+        s->regs[addr] = value;
+        break;
+    case R_TIMER0_CONTROL:
+        s->regs[addr] = value;
+        if (s->regs[R_TIMER0_CONTROL] & CTRL_ENABLE) {
+            trace_milkymist_sysctl_start_timer1();
+            ptimer_run(s->ptimer0, 0);
+        } else {
+            trace_milkymist_sysctl_stop_timer1();
+            ptimer_stop(s->ptimer0);
+        }
+        break;
+    case R_TIMER1_CONTROL:
+        s->regs[addr] = value;
+        if (s->regs[R_TIMER1_CONTROL] & CTRL_ENABLE) {
+            trace_milkymist_sysctl_start_timer1();
+            ptimer_run(s->ptimer1, 0);
+        } else {
+            trace_milkymist_sysctl_stop_timer1();
+            ptimer_stop(s->ptimer1);
+        }
+        break;
+    case R_ICAP:
+        sysctl_icap_write(s, value);
+        break;
+    case R_SYSTEM_ID:
+        qemu_system_reset_request();
+        break;
+
+    case R_GPIO_IN:
+    case R_CAPABILITIES:
+        error_report("milkymist_sysctl: write to read-only register 0x"
+                TARGET_FMT_plx, addr << 2);
+        break;
+
+    default:
+        error_report("milkymist_sysctl: write access to unkown register 0x"
+                TARGET_FMT_plx, addr << 2);
+        break;
+    }
+}
+
+static CPUReadMemoryFunc * const sysctl_read_fn[] = {
+    NULL,
+    NULL,
+    &sysctl_read,
+};
+
+static CPUWriteMemoryFunc * const sysctl_write_fn[] = {
+    NULL,
+    NULL,
+    &sysctl_write,
+};
+
+static void timer0_hit(void *opaque)
+{
+    MilkymistSysctlState *s = opaque;
+
+    if (!(s->regs[R_TIMER0_CONTROL] & CTRL_AUTORESTART)) {
+        s->regs[R_TIMER0_CONTROL] &= ~CTRL_ENABLE;
+        trace_milkymist_sysctl_stop_timer0();
+        ptimer_stop(s->ptimer0);
+    }
+
+    trace_milkymist_sysctl_pulse_irq_timer0();
+    qemu_irq_pulse(s->timer0_irq);
+}
+
+static void timer1_hit(void *opaque)
+{
+    MilkymistSysctlState *s = opaque;
+
+    if (!(s->regs[R_TIMER1_CONTROL] & CTRL_AUTORESTART)) {
+        s->regs[R_TIMER1_CONTROL] &= ~CTRL_ENABLE;
+        trace_milkymist_sysctl_stop_timer1();
+        ptimer_stop(s->ptimer1);
+    }
+
+    trace_milkymist_sysctl_pulse_irq_timer1();
+    qemu_irq_pulse(s->timer1_irq);
+}
+
+static void milkymist_sysctl_reset(DeviceState *d)
+{
+    MilkymistSysctlState *s =
+            container_of(d, MilkymistSysctlState, busdev.qdev);
+    int i;
+
+    for (i = 0; i < R_MAX; i++) {
+        s->regs[i] = 0;
+    }
+
+    ptimer_stop(s->ptimer0);
+    ptimer_stop(s->ptimer1);
+
+    /* defaults */
+    s->regs[R_ICAP] = ICAP_READY;
+    s->regs[R_SYSTEM_ID] = s->systemid;
+    s->regs[R_CAPABILITIES] = s->capabilities;
+    s->regs[R_GPIO_IN] = s->strappings;
+}
+
+static int milkymist_sysctl_init(SysBusDevice *dev)
+{
+    MilkymistSysctlState *s = FROM_SYSBUS(typeof(*s), dev);
+    int sysctl_regs;
+
+    sysbus_init_irq(dev, &s->gpio_irq);
+    sysbus_init_irq(dev, &s->timer0_irq);
+    sysbus_init_irq(dev, &s->timer1_irq);
+
+    s->bh0 = qemu_bh_new(timer0_hit, s);
+    s->bh1 = qemu_bh_new(timer1_hit, s);
+    s->ptimer0 = ptimer_init(s->bh0);
+    s->ptimer1 = ptimer_init(s->bh1);
+    ptimer_set_freq(s->ptimer0, s->freq_hz);
+    ptimer_set_freq(s->ptimer1, s->freq_hz);
+
+    sysctl_regs = cpu_register_io_memory(sysctl_read_fn, sysctl_write_fn, s,
+            DEVICE_NATIVE_ENDIAN);
+    sysbus_init_mmio(dev, R_MAX * 4, sysctl_regs);
+
+    return 0;
+}
+
+static const VMStateDescription vmstate_milkymist_sysctl = {
+    .name = "milkymist-sysctl",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .minimum_version_id_old = 1,
+    .fields      = (VMStateField[]) {
+        VMSTATE_UINT32_ARRAY(regs, MilkymistSysctlState, R_MAX),
+        VMSTATE_PTIMER(ptimer0, MilkymistSysctlState),
+        VMSTATE_PTIMER(ptimer1, MilkymistSysctlState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static SysBusDeviceInfo milkymist_sysctl_info = {
+    .init = milkymist_sysctl_init,
+    .qdev.name  = "milkymist-sysctl",
+    .qdev.size  = sizeof(MilkymistSysctlState),
+    .qdev.vmsd  = &vmstate_milkymist_sysctl,
+    .qdev.reset = milkymist_sysctl_reset,
+    .qdev.props = (Property[]) {
+        DEFINE_PROP_UINT32("frequency", MilkymistSysctlState,
+                freq_hz, 80000000),
+        DEFINE_PROP_UINT32("capabilities", MilkymistSysctlState,
+                capabilities, 0x00000000),
+        DEFINE_PROP_UINT32("systemid", MilkymistSysctlState,
+                systemid, 0x10014d31),
+        DEFINE_PROP_UINT32("gpio_strappings", MilkymistSysctlState,
+                strappings, 0x00000001),
+        DEFINE_PROP_END_OF_LIST(),
+    }
+};
+
+static void milkymist_sysctl_register(void)
+{
+    sysbus_register_withprop(&milkymist_sysctl_info);
+}
+
+device_init(milkymist_sysctl_register)