hw/timer: Add NPCM7xx Timer device model

The NPCM730 and NPCM750 SoCs have three timer modules each holding five
timers and some shared registers (e.g. interrupt status).

Each timer runs at 25 MHz divided by a prescaler, and counts down from a
configurable initial value to zero. When zero is reached, the interrupt
flag for the timer is set, and the timer is disabled (one-shot mode) or
reloaded from its initial value (periodic mode).

This implementation is sufficient to boot a Linux kernel configured for
NPCM750. Note that the kernel does not seem to actually turn on the
interrupts.

Reviewed-by: Tyrone Ting <kfting@nuvoton.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Alexander Bulekov <alxndr@bu.edu>
Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Havard Skinnemoen <hskinnemoen@google.com>
Message-id: 20200911052101.2602693-4-hskinnemoen@google.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 78 insertions, 0 deletions

diff --git a/include/hw/timer/npcm7xx_timer.h b/include/hw/timer/npcm7xx_timer.h
new file mode 100644
index 0000000000..878a365a79
--- /dev/null
+++ b/include/hw/timer/npcm7xx_timer.h
@@ -0,0 +1,78 @@
+/*
+ * Nuvoton NPCM7xx Timer Controller
+ *
+ * Copyright 2020 Google LLC
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License
+ * for more details.
+ */
+#ifndef NPCM7XX_TIMER_H
+#define NPCM7XX_TIMER_H
+
+#include "exec/memory.h"
+#include "hw/sysbus.h"
+#include "qemu/timer.h"
+
+/* Each Timer Module (TIM) instance holds five 25 MHz timers. */
+#define NPCM7XX_TIMERS_PER_CTRL (5)
+
+/*
+ * Number of registers in our device state structure. Don't change this without
+ * incrementing the version_id in the vmstate.
+ */
+#define NPCM7XX_TIMER_NR_REGS (0x54 / sizeof(uint32_t))
+
+typedef struct NPCM7xxTimerCtrlState NPCM7xxTimerCtrlState;
+
+/**
+ * struct NPCM7xxTimer - Individual timer state.
+ * @irq: GIC interrupt line to fire on expiration (if enabled).
+ * @qtimer: QEMU timer that notifies us on expiration.
+ * @expires_ns: Absolute virtual expiration time.
+ * @remaining_ns: Remaining time until expiration if timer is paused.
+ * @tcsr: The Timer Control and Status Register.
+ * @ticr: The Timer Initial Count Register.
+ */
+typedef struct NPCM7xxTimer {
+    NPCM7xxTimerCtrlState *ctrl;
+
+    qemu_irq    irq;
+    QEMUTimer   qtimer;
+    int64_t     expires_ns;
+    int64_t     remaining_ns;
+
+    uint32_t    tcsr;
+    uint32_t    ticr;
+} NPCM7xxTimer;
+
+/**
+ * struct NPCM7xxTimerCtrlState - Timer Module device state.
+ * @parent: System bus device.
+ * @iomem: Memory region through which registers are accessed.
+ * @tisr: The Timer Interrupt Status Register.
+ * @wtcr: The Watchdog Timer Control Register.
+ * @timer: The five individual timers managed by this module.
+ */
+struct NPCM7xxTimerCtrlState {
+    SysBusDevice parent;
+
+    MemoryRegion iomem;
+
+    uint32_t    tisr;
+    uint32_t    wtcr;
+
+    NPCM7xxTimer timer[NPCM7XX_TIMERS_PER_CTRL];
+};
+
+#define TYPE_NPCM7XX_TIMER "npcm7xx-timer"
+#define NPCM7XX_TIMER(obj)                                              \
+    OBJECT_CHECK(NPCM7xxTimerCtrlState, (obj), TYPE_NPCM7XX_TIMER)
+
+#endif /* NPCM7XX_TIMER_H */