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-rw-r--r--hw/watchdog/cmsdk-apb-watchdog.c414
1 files changed, 414 insertions, 0 deletions
diff --git a/hw/watchdog/cmsdk-apb-watchdog.c b/hw/watchdog/cmsdk-apb-watchdog.c
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+++ b/hw/watchdog/cmsdk-apb-watchdog.c
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+/*
+ * ARM CMSDK APB watchdog emulation
+ *
+ * Copyright (c) 2018 Linaro Limited
+ * Written by Peter Maydell
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 or
+ * (at your option) any later version.
+ */
+
+/*
+ * This is a model of the "APB watchdog" which is part of the Cortex-M
+ * System Design Kit (CMSDK) and documented in the Cortex-M System
+ * Design Kit Technical Reference Manual (ARM DDI0479C):
+ * https://developer.arm.com/products/system-design/system-design-kits/cortex-m-system-design-kit
+ *
+ * We also support the variant of this device found in the TI
+ * Stellaris/Luminary boards and documented in:
+ * http://www.ti.com/lit/ds/symlink/lm3s6965.pdf
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/log.h"
+#include "trace.h"
+#include "qapi/error.h"
+#include "qemu/module.h"
+#include "sysemu/watchdog.h"
+#include "hw/sysbus.h"
+#include "hw/irq.h"
+#include "hw/qdev-properties.h"
+#include "hw/registerfields.h"
+#include "hw/qdev-clock.h"
+#include "hw/watchdog/cmsdk-apb-watchdog.h"
+#include "migration/vmstate.h"
+
+REG32(WDOGLOAD, 0x0)
+REG32(WDOGVALUE, 0x4)
+REG32(WDOGCONTROL, 0x8)
+ FIELD(WDOGCONTROL, INTEN, 0, 1)
+ FIELD(WDOGCONTROL, RESEN, 1, 1)
+#define R_WDOGCONTROL_VALID_MASK (R_WDOGCONTROL_INTEN_MASK | \
+ R_WDOGCONTROL_RESEN_MASK)
+REG32(WDOGINTCLR, 0xc)
+REG32(WDOGRIS, 0x10)
+ FIELD(WDOGRIS, INT, 0, 1)
+REG32(WDOGMIS, 0x14)
+REG32(WDOGTEST, 0x418) /* only in Stellaris/Luminary version of the device */
+REG32(WDOGLOCK, 0xc00)
+#define WDOG_UNLOCK_VALUE 0x1ACCE551
+REG32(WDOGITCR, 0xf00)
+ FIELD(WDOGITCR, ENABLE, 0, 1)
+#define R_WDOGITCR_VALID_MASK R_WDOGITCR_ENABLE_MASK
+REG32(WDOGITOP, 0xf04)
+ FIELD(WDOGITOP, WDOGRES, 0, 1)
+ FIELD(WDOGITOP, WDOGINT, 1, 1)
+#define R_WDOGITOP_VALID_MASK (R_WDOGITOP_WDOGRES_MASK | \
+ R_WDOGITOP_WDOGINT_MASK)
+REG32(PID4, 0xfd0)
+REG32(PID5, 0xfd4)
+REG32(PID6, 0xfd8)
+REG32(PID7, 0xfdc)
+REG32(PID0, 0xfe0)
+REG32(PID1, 0xfe4)
+REG32(PID2, 0xfe8)
+REG32(PID3, 0xfec)
+REG32(CID0, 0xff0)
+REG32(CID1, 0xff4)
+REG32(CID2, 0xff8)
+REG32(CID3, 0xffc)
+
+/* PID/CID values */
+static const uint32_t cmsdk_apb_watchdog_id[] = {
+ 0x04, 0x00, 0x00, 0x00, /* PID4..PID7 */
+ 0x24, 0xb8, 0x1b, 0x00, /* PID0..PID3 */
+ 0x0d, 0xf0, 0x05, 0xb1, /* CID0..CID3 */
+};
+
+static const uint32_t luminary_watchdog_id[] = {
+ 0x00, 0x00, 0x00, 0x00, /* PID4..PID7 */
+ 0x05, 0x18, 0x18, 0x01, /* PID0..PID3 */
+ 0x0d, 0xf0, 0x05, 0xb1, /* CID0..CID3 */
+};
+
+static bool cmsdk_apb_watchdog_intstatus(CMSDKAPBWatchdog *s)
+{
+ /* Return masked interrupt status */
+ return s->intstatus && (s->control & R_WDOGCONTROL_INTEN_MASK);
+}
+
+static bool cmsdk_apb_watchdog_resetstatus(CMSDKAPBWatchdog *s)
+{
+ /* Return masked reset status */
+ return s->resetstatus && (s->control & R_WDOGCONTROL_RESEN_MASK);
+}
+
+static void cmsdk_apb_watchdog_update(CMSDKAPBWatchdog *s)
+{
+ bool wdogint;
+ bool wdogres;
+
+ if (s->itcr) {
+ /*
+ * Not checking that !s->is_luminary since s->itcr can't be written
+ * when s->is_luminary in the first place.
+ */
+ wdogint = s->itop & R_WDOGITOP_WDOGINT_MASK;
+ wdogres = s->itop & R_WDOGITOP_WDOGRES_MASK;
+ } else {
+ wdogint = cmsdk_apb_watchdog_intstatus(s);
+ wdogres = cmsdk_apb_watchdog_resetstatus(s);
+ }
+
+ qemu_set_irq(s->wdogint, wdogint);
+ if (wdogres) {
+ watchdog_perform_action();
+ }
+}
+
+static uint64_t cmsdk_apb_watchdog_read(void *opaque, hwaddr offset,
+ unsigned size)
+{
+ CMSDKAPBWatchdog *s = CMSDK_APB_WATCHDOG(opaque);
+ uint64_t r;
+
+ switch (offset) {
+ case A_WDOGLOAD:
+ r = ptimer_get_limit(s->timer);
+ break;
+ case A_WDOGVALUE:
+ r = ptimer_get_count(s->timer);
+ break;
+ case A_WDOGCONTROL:
+ r = s->control;
+ break;
+ case A_WDOGRIS:
+ r = s->intstatus;
+ break;
+ case A_WDOGMIS:
+ r = cmsdk_apb_watchdog_intstatus(s);
+ break;
+ case A_WDOGLOCK:
+ r = s->lock;
+ break;
+ case A_WDOGITCR:
+ if (s->is_luminary) {
+ goto bad_offset;
+ }
+ r = s->itcr;
+ break;
+ case A_PID4 ... A_CID3:
+ r = s->id[(offset - A_PID4) / 4];
+ break;
+ case A_WDOGINTCLR:
+ case A_WDOGITOP:
+ if (s->is_luminary) {
+ goto bad_offset;
+ }
+ qemu_log_mask(LOG_GUEST_ERROR,
+ "CMSDK APB watchdog read: read of WO offset %x\n",
+ (int)offset);
+ r = 0;
+ break;
+ case A_WDOGTEST:
+ if (!s->is_luminary) {
+ goto bad_offset;
+ }
+ qemu_log_mask(LOG_UNIMP,
+ "Luminary watchdog read: stall not implemented\n");
+ r = 0;
+ break;
+ default:
+bad_offset:
+ qemu_log_mask(LOG_GUEST_ERROR,
+ "CMSDK APB watchdog read: bad offset %x\n", (int)offset);
+ r = 0;
+ break;
+ }
+ trace_cmsdk_apb_watchdog_read(offset, r, size);
+ return r;
+}
+
+static void cmsdk_apb_watchdog_write(void *opaque, hwaddr offset,
+ uint64_t value, unsigned size)
+{
+ CMSDKAPBWatchdog *s = CMSDK_APB_WATCHDOG(opaque);
+
+ trace_cmsdk_apb_watchdog_write(offset, value, size);
+
+ if (s->lock && offset != A_WDOGLOCK) {
+ /* Write access is disabled via WDOGLOCK */
+ qemu_log_mask(LOG_GUEST_ERROR,
+ "CMSDK APB watchdog write: write to locked watchdog\n");
+ return;
+ }
+
+ switch (offset) {
+ case A_WDOGLOAD:
+ /*
+ * Reset the load value and the current count, and make sure
+ * we're counting.
+ */
+ ptimer_transaction_begin(s->timer);
+ ptimer_set_limit(s->timer, value, 1);
+ ptimer_run(s->timer, 0);
+ ptimer_transaction_commit(s->timer);
+ break;
+ case A_WDOGCONTROL:
+ if (s->is_luminary && 0 != (R_WDOGCONTROL_INTEN_MASK & s->control)) {
+ /*
+ * The Luminary version of this device ignores writes to
+ * this register after the guest has enabled interrupts
+ * (so they can only be disabled again via reset).
+ */
+ break;
+ }
+ s->control = value & R_WDOGCONTROL_VALID_MASK;
+ cmsdk_apb_watchdog_update(s);
+ break;
+ case A_WDOGINTCLR:
+ s->intstatus = 0;
+ ptimer_transaction_begin(s->timer);
+ ptimer_set_count(s->timer, ptimer_get_limit(s->timer));
+ ptimer_transaction_commit(s->timer);
+ cmsdk_apb_watchdog_update(s);
+ break;
+ case A_WDOGLOCK:
+ s->lock = (value != WDOG_UNLOCK_VALUE);
+ trace_cmsdk_apb_watchdog_lock(s->lock);
+ break;
+ case A_WDOGITCR:
+ if (s->is_luminary) {
+ goto bad_offset;
+ }
+ s->itcr = value & R_WDOGITCR_VALID_MASK;
+ cmsdk_apb_watchdog_update(s);
+ break;
+ case A_WDOGITOP:
+ if (s->is_luminary) {
+ goto bad_offset;
+ }
+ s->itop = value & R_WDOGITOP_VALID_MASK;
+ cmsdk_apb_watchdog_update(s);
+ break;
+ case A_WDOGVALUE:
+ case A_WDOGRIS:
+ case A_WDOGMIS:
+ case A_PID4 ... A_CID3:
+ qemu_log_mask(LOG_GUEST_ERROR,
+ "CMSDK APB watchdog write: write to RO offset 0x%x\n",
+ (int)offset);
+ break;
+ case A_WDOGTEST:
+ if (!s->is_luminary) {
+ goto bad_offset;
+ }
+ qemu_log_mask(LOG_UNIMP,
+ "Luminary watchdog write: stall not implemented\n");
+ break;
+ default:
+bad_offset:
+ qemu_log_mask(LOG_GUEST_ERROR,
+ "CMSDK APB watchdog write: bad offset 0x%x\n",
+ (int)offset);
+ break;
+ }
+}
+
+static const MemoryRegionOps cmsdk_apb_watchdog_ops = {
+ .read = cmsdk_apb_watchdog_read,
+ .write = cmsdk_apb_watchdog_write,
+ .endianness = DEVICE_LITTLE_ENDIAN,
+ /* byte/halfword accesses are just zero-padded on reads and writes */
+ .impl.min_access_size = 4,
+ .impl.max_access_size = 4,
+ .valid.min_access_size = 1,
+ .valid.max_access_size = 4,
+};
+
+static void cmsdk_apb_watchdog_tick(void *opaque)
+{
+ CMSDKAPBWatchdog *s = CMSDK_APB_WATCHDOG(opaque);
+
+ if (!s->intstatus) {
+ /* Count expired for the first time: raise interrupt */
+ s->intstatus = R_WDOGRIS_INT_MASK;
+ } else {
+ /* Count expired for the second time: raise reset and stop clock */
+ s->resetstatus = 1;
+ ptimer_stop(s->timer);
+ }
+ cmsdk_apb_watchdog_update(s);
+}
+
+static void cmsdk_apb_watchdog_reset(DeviceState *dev)
+{
+ CMSDKAPBWatchdog *s = CMSDK_APB_WATCHDOG(dev);
+
+ trace_cmsdk_apb_watchdog_reset();
+ s->control = 0;
+ s->intstatus = 0;
+ s->lock = 0;
+ s->itcr = 0;
+ s->itop = 0;
+ s->resetstatus = 0;
+ /* Set the limit and the count */
+ ptimer_transaction_begin(s->timer);
+ ptimer_set_limit(s->timer, 0xffffffff, 1);
+ ptimer_run(s->timer, 0);
+ ptimer_transaction_commit(s->timer);
+}
+
+static void cmsdk_apb_watchdog_clk_update(void *opaque, ClockEvent event)
+{
+ CMSDKAPBWatchdog *s = CMSDK_APB_WATCHDOG(opaque);
+
+ ptimer_transaction_begin(s->timer);
+ ptimer_set_period_from_clock(s->timer, s->wdogclk, 1);
+ ptimer_transaction_commit(s->timer);
+}
+
+static void cmsdk_apb_watchdog_init(Object *obj)
+{
+ SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
+ CMSDKAPBWatchdog *s = CMSDK_APB_WATCHDOG(obj);
+
+ memory_region_init_io(&s->iomem, obj, &cmsdk_apb_watchdog_ops,
+ s, "cmsdk-apb-watchdog", 0x1000);
+ sysbus_init_mmio(sbd, &s->iomem);
+ sysbus_init_irq(sbd, &s->wdogint);
+ s->wdogclk = qdev_init_clock_in(DEVICE(s), "WDOGCLK",
+ cmsdk_apb_watchdog_clk_update, s,
+ ClockUpdate);
+
+ s->is_luminary = false;
+ s->id = cmsdk_apb_watchdog_id;
+}
+
+static void cmsdk_apb_watchdog_realize(DeviceState *dev, Error **errp)
+{
+ CMSDKAPBWatchdog *s = CMSDK_APB_WATCHDOG(dev);
+
+ if (!clock_has_source(s->wdogclk)) {
+ error_setg(errp,
+ "CMSDK APB watchdog: WDOGCLK clock must be connected");
+ return;
+ }
+
+ s->timer = ptimer_init(cmsdk_apb_watchdog_tick, s,
+ PTIMER_POLICY_WRAP_AFTER_ONE_PERIOD |
+ PTIMER_POLICY_TRIGGER_ONLY_ON_DECREMENT |
+ PTIMER_POLICY_NO_IMMEDIATE_RELOAD |
+ PTIMER_POLICY_NO_COUNTER_ROUND_DOWN);
+
+ ptimer_transaction_begin(s->timer);
+ ptimer_set_period_from_clock(s->timer, s->wdogclk, 1);
+ ptimer_transaction_commit(s->timer);
+}
+
+static const VMStateDescription cmsdk_apb_watchdog_vmstate = {
+ .name = "cmsdk-apb-watchdog",
+ .version_id = 2,
+ .minimum_version_id = 2,
+ .fields = (VMStateField[]) {
+ VMSTATE_CLOCK(wdogclk, CMSDKAPBWatchdog),
+ VMSTATE_PTIMER(timer, CMSDKAPBWatchdog),
+ VMSTATE_UINT32(control, CMSDKAPBWatchdog),
+ VMSTATE_UINT32(intstatus, CMSDKAPBWatchdog),
+ VMSTATE_UINT32(lock, CMSDKAPBWatchdog),
+ VMSTATE_UINT32(itcr, CMSDKAPBWatchdog),
+ VMSTATE_UINT32(itop, CMSDKAPBWatchdog),
+ VMSTATE_UINT32(resetstatus, CMSDKAPBWatchdog),
+ VMSTATE_END_OF_LIST()
+ }
+};
+
+static void cmsdk_apb_watchdog_class_init(ObjectClass *klass, void *data)
+{
+ DeviceClass *dc = DEVICE_CLASS(klass);
+
+ dc->realize = cmsdk_apb_watchdog_realize;
+ dc->vmsd = &cmsdk_apb_watchdog_vmstate;
+ dc->reset = cmsdk_apb_watchdog_reset;
+}
+
+static const TypeInfo cmsdk_apb_watchdog_info = {
+ .name = TYPE_CMSDK_APB_WATCHDOG,
+ .parent = TYPE_SYS_BUS_DEVICE,
+ .instance_size = sizeof(CMSDKAPBWatchdog),
+ .instance_init = cmsdk_apb_watchdog_init,
+ .class_init = cmsdk_apb_watchdog_class_init,
+};
+
+static void luminary_watchdog_init(Object *obj)
+{
+ CMSDKAPBWatchdog *s = CMSDK_APB_WATCHDOG(obj);
+
+ s->is_luminary = true;
+ s->id = luminary_watchdog_id;
+}
+
+static const TypeInfo luminary_watchdog_info = {
+ .name = TYPE_LUMINARY_WATCHDOG,
+ .parent = TYPE_CMSDK_APB_WATCHDOG,
+ .instance_init = luminary_watchdog_init
+};
+
+static void cmsdk_apb_watchdog_register_types(void)
+{
+ type_register_static(&cmsdk_apb_watchdog_info);
+ type_register_static(&luminary_watchdog_info);
+}
+
+type_init(cmsdk_apb_watchdog_register_types);