hw/misc: Add NPCM7XX MFT Module

This patch implements Multi Function Timer (MFT) module for NPCM7XX.
This module is mainly used to configure PWM fans. It has just enough
functionality to make the PWM fan kernel module work.

The module takes two input, the max_rpm of a fan (modifiable via QMP)
and duty cycle (a GPIO from the PWM module.) The actual measured RPM
is equal to max_rpm * duty_cycle / NPCM7XX_PWM_MAX_DUTY. The RPM is
measured as a counter compared to a prescaled input clock. The kernel
driver reads this counter and report to user space.

Refs:
https://github.com/torvalds/linux/blob/master/drivers/hwmon/npcm750-pwm-fan.c

Reviewed-by: Doug Evans <dje@google.com>
Reviewed-by: Tyrone Ting <kfting@nuvoton.com>
Signed-off-by: Hao Wu <wuhaotsh@google.com>
Message-id: 20210311180855.149764-3-wuhaotsh@google.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

4 files changed, 619 insertions, 0 deletions

diff --git a/hw/misc/meson.build b/hw/misc/meson.build
index 65b6bb0..7a2b0d0 100644
--- a/hw/misc/meson.build
+++ b/hw/misc/meson.build
@@ -65,6 +65,7 @@ softmmu_ss.add(when: 'CONFIG_MAINSTONE', if_true: files('mst_fpga.c'))
 softmmu_ss.add(when: 'CONFIG_NPCM7XX', if_true: files(
   'npcm7xx_clk.c',
   'npcm7xx_gcr.c',
+  'npcm7xx_mft.c',
   'npcm7xx_pwm.c',
   'npcm7xx_rng.c',
 ))
diff --git a/hw/misc/npcm7xx_mft.c b/hw/misc/npcm7xx_mft.c
new file mode 100644
index 0000000..a30583a
--- /dev/null
+++ b/hw/misc/npcm7xx_mft.c
@@ -0,0 +1,540 @@
+/*
+ * Nuvoton NPCM7xx MFT Module
+ *
+ * Copyright 2021 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.
+ */
+
+#include "qemu/osdep.h"
+#include "hw/irq.h"
+#include "hw/qdev-clock.h"
+#include "hw/qdev-properties.h"
+#include "hw/misc/npcm7xx_mft.h"
+#include "hw/misc/npcm7xx_pwm.h"
+#include "hw/registerfields.h"
+#include "migration/vmstate.h"
+#include "qapi/error.h"
+#include "qapi/visitor.h"
+#include "qemu/bitops.h"
+#include "qemu/error-report.h"
+#include "qemu/log.h"
+#include "qemu/module.h"
+#include "qemu/timer.h"
+#include "qemu/units.h"
+#include "trace.h"
+
+/*
+ * Some of the registers can only accessed via 16-bit ops and some can only
+ * be accessed via 8-bit ops. However we mark all of them using REG16 to
+ * simplify implementation. npcm7xx_mft_check_mem_op checks the access length
+ * of memory operations.
+ */
+REG16(NPCM7XX_MFT_CNT1, 0x00);
+REG16(NPCM7XX_MFT_CRA, 0x02);
+REG16(NPCM7XX_MFT_CRB, 0x04);
+REG16(NPCM7XX_MFT_CNT2, 0x06);
+REG16(NPCM7XX_MFT_PRSC, 0x08);
+REG16(NPCM7XX_MFT_CKC, 0x0a);
+REG16(NPCM7XX_MFT_MCTRL, 0x0c);
+REG16(NPCM7XX_MFT_ICTRL, 0x0e);
+REG16(NPCM7XX_MFT_ICLR, 0x10);
+REG16(NPCM7XX_MFT_IEN, 0x12);
+REG16(NPCM7XX_MFT_CPA, 0x14);
+REG16(NPCM7XX_MFT_CPB, 0x16);
+REG16(NPCM7XX_MFT_CPCFG, 0x18);
+REG16(NPCM7XX_MFT_INASEL, 0x1a);
+REG16(NPCM7XX_MFT_INBSEL, 0x1c);
+
+/* Register Fields */
+#define NPCM7XX_MFT_CKC_C2CSEL          BIT(3)
+#define NPCM7XX_MFT_CKC_C1CSEL          BIT(0)
+
+#define NPCM7XX_MFT_MCTRL_TBEN          BIT(6)
+#define NPCM7XX_MFT_MCTRL_TAEN          BIT(5)
+#define NPCM7XX_MFT_MCTRL_TBEDG         BIT(4)
+#define NPCM7XX_MFT_MCTRL_TAEDG         BIT(3)
+#define NPCM7XX_MFT_MCTRL_MODE5         BIT(2)
+
+#define NPCM7XX_MFT_ICTRL_TFPND         BIT(5)
+#define NPCM7XX_MFT_ICTRL_TEPND         BIT(4)
+#define NPCM7XX_MFT_ICTRL_TDPND         BIT(3)
+#define NPCM7XX_MFT_ICTRL_TCPND         BIT(2)
+#define NPCM7XX_MFT_ICTRL_TBPND         BIT(1)
+#define NPCM7XX_MFT_ICTRL_TAPND         BIT(0)
+
+#define NPCM7XX_MFT_ICLR_TFCLR          BIT(5)
+#define NPCM7XX_MFT_ICLR_TECLR          BIT(4)
+#define NPCM7XX_MFT_ICLR_TDCLR          BIT(3)
+#define NPCM7XX_MFT_ICLR_TCCLR          BIT(2)
+#define NPCM7XX_MFT_ICLR_TBCLR          BIT(1)
+#define NPCM7XX_MFT_ICLR_TACLR          BIT(0)
+
+#define NPCM7XX_MFT_IEN_TFIEN           BIT(5)
+#define NPCM7XX_MFT_IEN_TEIEN           BIT(4)
+#define NPCM7XX_MFT_IEN_TDIEN           BIT(3)
+#define NPCM7XX_MFT_IEN_TCIEN           BIT(2)
+#define NPCM7XX_MFT_IEN_TBIEN           BIT(1)
+#define NPCM7XX_MFT_IEN_TAIEN           BIT(0)
+
+#define NPCM7XX_MFT_CPCFG_GET_B(rv)     extract8((rv), 4, 4)
+#define NPCM7XX_MFT_CPCFG_GET_A(rv)     extract8((rv), 0, 4)
+#define NPCM7XX_MFT_CPCFG_HIEN          BIT(3)
+#define NPCM7XX_MFT_CPCFG_EQEN          BIT(2)
+#define NPCM7XX_MFT_CPCFG_LOEN          BIT(1)
+#define NPCM7XX_MFT_CPCFG_CPSEL         BIT(0)
+
+#define NPCM7XX_MFT_INASEL_SELA         BIT(0)
+#define NPCM7XX_MFT_INBSEL_SELB         BIT(0)
+
+/* Max CNT values of the module. The CNT value is a countdown from it. */
+#define NPCM7XX_MFT_MAX_CNT             0xFFFF
+
+/* Each fan revolution should generated 2 pulses */
+#define NPCM7XX_MFT_PULSE_PER_REVOLUTION 2
+
+typedef enum NPCM7xxMFTCaptureState {
+    /* capture succeeded with a valid CNT value. */
+    NPCM7XX_CAPTURE_SUCCEED,
+    /* capture stopped prematurely due to reaching CPCFG condition. */
+    NPCM7XX_CAPTURE_COMPARE_HIT,
+    /* capture fails since it reaches underflow condition for CNT. */
+    NPCM7XX_CAPTURE_UNDERFLOW,
+} NPCM7xxMFTCaptureState;
+
+static void npcm7xx_mft_reset(NPCM7xxMFTState *s)
+{
+    int i;
+
+    /* Only registers PRSC ~ INBSEL need to be reset. */
+    for (i = R_NPCM7XX_MFT_PRSC; i <= R_NPCM7XX_MFT_INBSEL; ++i) {
+        s->regs[i] = 0;
+    }
+}
+
+static void npcm7xx_mft_clear_interrupt(NPCM7xxMFTState *s, uint8_t iclr)
+{
+    /*
+     * Clear bits in ICTRL where corresponding bits in iclr is 1.
+     * Both iclr and ictrl are 8-bit regs. (See npcm7xx_mft_check_mem_op)
+     */
+    s->regs[R_NPCM7XX_MFT_ICTRL] &= ~iclr;
+}
+
+/*
+ * If the CPCFG's condition should be triggered during count down from
+ * NPCM7XX_MFT_MAX_CNT to src if compared to tgt, return the count when
+ * the condition is triggered.
+ * Otherwise return -1.
+ * Since tgt is uint16_t it must always <= NPCM7XX_MFT_MAX_CNT.
+ */
+static int npcm7xx_mft_compare(int32_t src, uint16_t tgt, uint8_t cpcfg)
+{
+    if (cpcfg & NPCM7XX_MFT_CPCFG_HIEN) {
+        return NPCM7XX_MFT_MAX_CNT;
+    }
+    if ((cpcfg & NPCM7XX_MFT_CPCFG_EQEN) && (src <= tgt)) {
+        return tgt;
+    }
+    if ((cpcfg & NPCM7XX_MFT_CPCFG_LOEN) && (tgt > 0) && (src < tgt)) {
+        return tgt - 1;
+    }
+
+    return -1;
+}
+
+/* Compute CNT according to corresponding fan's RPM. */
+static NPCM7xxMFTCaptureState npcm7xx_mft_compute_cnt(
+    Clock *clock, uint32_t max_rpm, uint32_t duty, uint16_t tgt,
+    uint8_t cpcfg, uint16_t *cnt)
+{
+    uint32_t rpm = (uint64_t)max_rpm * (uint64_t)duty / NPCM7XX_PWM_MAX_DUTY;
+    int32_t count;
+    int stopped;
+    NPCM7xxMFTCaptureState state;
+
+    if (rpm == 0) {
+        /*
+         * If RPM = 0, capture won't happen. CNT will continue count down.
+         * So it's effective equivalent to have a cnt > NPCM7XX_MFT_MAX_CNT
+         */
+        count = NPCM7XX_MFT_MAX_CNT + 1;
+    } else {
+        /*
+         * RPM = revolution/min. The time for one revlution (in ns) is
+         * MINUTE_TO_NANOSECOND / RPM.
+         */
+        count = clock_ns_to_ticks(clock, (60 * NANOSECONDS_PER_SECOND) /
+            (rpm * NPCM7XX_MFT_PULSE_PER_REVOLUTION));
+    }
+
+    if (count > NPCM7XX_MFT_MAX_CNT) {
+        count = -1;
+    } else {
+        /* The CNT is a countdown value from NPCM7XX_MFT_MAX_CNT. */
+        count = NPCM7XX_MFT_MAX_CNT - count;
+    }
+    stopped = npcm7xx_mft_compare(count, tgt, cpcfg);
+    if (stopped == -1) {
+        if (count == -1) {
+            /* Underflow */
+            state = NPCM7XX_CAPTURE_UNDERFLOW;
+        } else {
+            state = NPCM7XX_CAPTURE_SUCCEED;
+        }
+    } else {
+        count = stopped;
+        state = NPCM7XX_CAPTURE_COMPARE_HIT;
+    }
+
+    if (count != -1) {
+        *cnt = count;
+    }
+    trace_npcm7xx_mft_rpm(clock->canonical_path, clock_get_hz(clock),
+                          state, count, rpm, duty);
+    return state;
+}
+
+/*
+ * Capture Fan RPM and update CNT and CR registers accordingly.
+ * Raise IRQ if certain contidions are met in IEN.
+ */
+static void npcm7xx_mft_capture(NPCM7xxMFTState *s)
+{
+    int irq_level = 0;
+    NPCM7xxMFTCaptureState state;
+    int sel;
+    uint8_t cpcfg;
+
+    /*
+     * If not mode 5, the behavior is undefined. We just do nothing in this
+     * case.
+     */
+    if (!(s->regs[R_NPCM7XX_MFT_MCTRL] & NPCM7XX_MFT_MCTRL_MODE5)) {
+        return;
+    }
+
+    /* Capture input A. */
+    if (s->regs[R_NPCM7XX_MFT_MCTRL] & NPCM7XX_MFT_MCTRL_TAEN &&
+        s->regs[R_NPCM7XX_MFT_CKC] & NPCM7XX_MFT_CKC_C1CSEL) {
+        sel = s->regs[R_NPCM7XX_MFT_INASEL] & NPCM7XX_MFT_INASEL_SELA;
+        cpcfg = NPCM7XX_MFT_CPCFG_GET_A(s->regs[R_NPCM7XX_MFT_CPCFG]);
+        state = npcm7xx_mft_compute_cnt(s->clock_1,
+                                        sel ? s->max_rpm[2] : s->max_rpm[0],
+                                        sel ? s->duty[2] : s->duty[0],
+                                        s->regs[R_NPCM7XX_MFT_CPA],
+                                        cpcfg,
+                                        &s->regs[R_NPCM7XX_MFT_CNT1]);
+        switch (state) {
+        case NPCM7XX_CAPTURE_SUCCEED:
+            /* Interrupt on input capture on TAn transition - TAPND */
+            s->regs[R_NPCM7XX_MFT_CRA] = s->regs[R_NPCM7XX_MFT_CNT1];
+            s->regs[R_NPCM7XX_MFT_ICTRL] |= NPCM7XX_MFT_ICTRL_TAPND;
+            if (s->regs[R_NPCM7XX_MFT_IEN] & NPCM7XX_MFT_IEN_TAIEN) {
+                irq_level = 1;
+            }
+            break;
+
+        case NPCM7XX_CAPTURE_COMPARE_HIT:
+            /* Compare Hit - TEPND */
+            s->regs[R_NPCM7XX_MFT_ICTRL] |= NPCM7XX_MFT_ICTRL_TEPND;
+            if (s->regs[R_NPCM7XX_MFT_IEN] & NPCM7XX_MFT_IEN_TEIEN) {
+                irq_level = 1;
+            }
+            break;
+
+        case NPCM7XX_CAPTURE_UNDERFLOW:
+            /* Underflow - TCPND */
+            s->regs[R_NPCM7XX_MFT_ICTRL] |= NPCM7XX_MFT_ICTRL_TCPND;
+            if (s->regs[R_NPCM7XX_MFT_IEN] & NPCM7XX_MFT_IEN_TCIEN) {
+                irq_level = 1;
+            }
+            break;
+
+        default:
+            g_assert_not_reached();
+        }
+    }
+
+    /* Capture input B. */
+    if (s->regs[R_NPCM7XX_MFT_MCTRL] & NPCM7XX_MFT_MCTRL_TBEN &&
+        s->regs[R_NPCM7XX_MFT_CKC] & NPCM7XX_MFT_CKC_C2CSEL) {
+        sel = s->regs[R_NPCM7XX_MFT_INBSEL] & NPCM7XX_MFT_INBSEL_SELB;
+        cpcfg = NPCM7XX_MFT_CPCFG_GET_B(s->regs[R_NPCM7XX_MFT_CPCFG]);
+        state = npcm7xx_mft_compute_cnt(s->clock_2,
+                                        sel ? s->max_rpm[3] : s->max_rpm[1],
+                                        sel ? s->duty[3] : s->duty[1],
+                                        s->regs[R_NPCM7XX_MFT_CPB],
+                                        cpcfg,
+                                        &s->regs[R_NPCM7XX_MFT_CNT2]);
+        switch (state) {
+        case NPCM7XX_CAPTURE_SUCCEED:
+            /* Interrupt on input capture on TBn transition - TBPND */
+            s->regs[R_NPCM7XX_MFT_CRB] = s->regs[R_NPCM7XX_MFT_CNT2];
+            s->regs[R_NPCM7XX_MFT_ICTRL] |= NPCM7XX_MFT_ICTRL_TBPND;
+            if (s->regs[R_NPCM7XX_MFT_IEN] & NPCM7XX_MFT_IEN_TBIEN) {
+                irq_level = 1;
+            }
+            break;
+
+        case NPCM7XX_CAPTURE_COMPARE_HIT:
+            /* Compare Hit - TFPND */
+            s->regs[R_NPCM7XX_MFT_ICTRL] |= NPCM7XX_MFT_ICTRL_TFPND;
+            if (s->regs[R_NPCM7XX_MFT_IEN] & NPCM7XX_MFT_IEN_TFIEN) {
+                irq_level = 1;
+            }
+            break;
+
+        case NPCM7XX_CAPTURE_UNDERFLOW:
+            /* Underflow - TDPND */
+            s->regs[R_NPCM7XX_MFT_ICTRL] |= NPCM7XX_MFT_ICTRL_TDPND;
+            if (s->regs[R_NPCM7XX_MFT_IEN] & NPCM7XX_MFT_IEN_TDIEN) {
+                irq_level = 1;
+            }
+            break;
+
+        default:
+            g_assert_not_reached();
+        }
+    }
+
+    trace_npcm7xx_mft_capture(DEVICE(s)->canonical_path, irq_level);
+    qemu_set_irq(s->irq, irq_level);
+}
+
+/* Update clock for counters. */
+static void npcm7xx_mft_update_clock(void *opaque, ClockEvent event)
+{
+    NPCM7xxMFTState *s = NPCM7XX_MFT(opaque);
+    uint64_t prescaled_clock_period;
+
+    prescaled_clock_period = clock_get(s->clock_in) *
+        (s->regs[R_NPCM7XX_MFT_PRSC] + 1ULL);
+    trace_npcm7xx_mft_update_clock(s->clock_in->canonical_path,
+                                   s->regs[R_NPCM7XX_MFT_CKC],
+                                   clock_get(s->clock_in),
+                                   prescaled_clock_period);
+    /* Update clock 1 */
+    if (s->regs[R_NPCM7XX_MFT_CKC] & NPCM7XX_MFT_CKC_C1CSEL) {
+        /* Clock is prescaled. */
+        clock_update(s->clock_1, prescaled_clock_period);
+    } else {
+        /* Clock stopped. */
+        clock_update(s->clock_1, 0);
+    }
+    /* Update clock 2 */
+    if (s->regs[R_NPCM7XX_MFT_CKC] & NPCM7XX_MFT_CKC_C2CSEL) {
+        /* Clock is prescaled. */
+        clock_update(s->clock_2, prescaled_clock_period);
+    } else {
+        /* Clock stopped. */
+        clock_update(s->clock_2, 0);
+    }
+
+    npcm7xx_mft_capture(s);
+}
+
+static uint64_t npcm7xx_mft_read(void *opaque, hwaddr offset, unsigned size)
+{
+    NPCM7xxMFTState *s = NPCM7XX_MFT(opaque);
+    uint16_t value = 0;
+
+    switch (offset) {
+    case A_NPCM7XX_MFT_ICLR:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: register @ 0x%04" HWADDR_PRIx " is write-only\n",
+                      __func__, offset);
+        break;
+
+    default:
+        value = s->regs[offset / 2];
+    }
+
+    trace_npcm7xx_mft_read(DEVICE(s)->canonical_path, offset, value);
+    return value;
+}
+
+static void npcm7xx_mft_write(void *opaque, hwaddr offset,
+                              uint64_t v, unsigned size)
+{
+    NPCM7xxMFTState *s = NPCM7XX_MFT(opaque);
+
+    trace_npcm7xx_mft_write(DEVICE(s)->canonical_path, offset, v);
+    switch (offset) {
+    case A_NPCM7XX_MFT_ICLR:
+        npcm7xx_mft_clear_interrupt(s, v);
+        break;
+
+    case A_NPCM7XX_MFT_CKC:
+    case A_NPCM7XX_MFT_PRSC:
+        s->regs[offset / 2] = v;
+        npcm7xx_mft_update_clock(s, ClockUpdate);
+        break;
+
+    default:
+        s->regs[offset / 2] = v;
+        npcm7xx_mft_capture(s);
+        break;
+    }
+}
+
+static bool npcm7xx_mft_check_mem_op(void *opaque, hwaddr offset,
+                                     unsigned size, bool is_write,
+                                     MemTxAttrs attrs)
+{
+    switch (offset) {
+    /* 16-bit registers. Must be accessed with 16-bit read/write.*/
+    case A_NPCM7XX_MFT_CNT1:
+    case A_NPCM7XX_MFT_CRA:
+    case A_NPCM7XX_MFT_CRB:
+    case A_NPCM7XX_MFT_CNT2:
+    case A_NPCM7XX_MFT_CPA:
+    case A_NPCM7XX_MFT_CPB:
+        return size == 2;
+
+    /* 8-bit registers. Must be accessed with 8-bit read/write.*/
+    case A_NPCM7XX_MFT_PRSC:
+    case A_NPCM7XX_MFT_CKC:
+    case A_NPCM7XX_MFT_MCTRL:
+    case A_NPCM7XX_MFT_ICTRL:
+    case A_NPCM7XX_MFT_ICLR:
+    case A_NPCM7XX_MFT_IEN:
+    case A_NPCM7XX_MFT_CPCFG:
+    case A_NPCM7XX_MFT_INASEL:
+    case A_NPCM7XX_MFT_INBSEL:
+        return size == 1;
+
+    default:
+        /* Invalid registers. */
+        return false;
+    }
+}
+
+static void npcm7xx_mft_get_max_rpm(Object *obj, Visitor *v, const char *name,
+                                    void *opaque, Error **errp)
+{
+    visit_type_uint32(v, name, (uint32_t *)opaque, errp);
+}
+
+static void npcm7xx_mft_set_max_rpm(Object *obj, Visitor *v, const char *name,
+                                    void *opaque, Error **errp)
+{
+    NPCM7xxMFTState *s = NPCM7XX_MFT(obj);
+    uint32_t *max_rpm = opaque;
+    uint32_t value;
+
+    if (!visit_type_uint32(v, name, &value, errp)) {
+        return;
+    }
+
+    *max_rpm = value;
+    npcm7xx_mft_capture(s);
+}
+
+static void npcm7xx_mft_duty_handler(void *opaque, int n, int value)
+{
+    NPCM7xxMFTState *s = NPCM7XX_MFT(opaque);
+
+    trace_npcm7xx_mft_set_duty(DEVICE(s)->canonical_path, n, value);
+    s->duty[n] = value;
+    npcm7xx_mft_capture(s);
+}
+
+static const struct MemoryRegionOps npcm7xx_mft_ops = {
+    .read       = npcm7xx_mft_read,
+    .write      = npcm7xx_mft_write,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+    .valid      = {
+        .min_access_size        = 1,
+        .max_access_size        = 2,
+        .unaligned              = false,
+        .accepts                = npcm7xx_mft_check_mem_op,
+    },
+};
+
+static void npcm7xx_mft_enter_reset(Object *obj, ResetType type)
+{
+    NPCM7xxMFTState *s = NPCM7XX_MFT(obj);
+
+    npcm7xx_mft_reset(s);
+}
+
+static void npcm7xx_mft_hold_reset(Object *obj)
+{
+    NPCM7xxMFTState *s = NPCM7XX_MFT(obj);
+
+    qemu_irq_lower(s->irq);
+}
+
+static void npcm7xx_mft_init(Object *obj)
+{
+    NPCM7xxMFTState *s = NPCM7XX_MFT(obj);
+    SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
+    DeviceState *dev = DEVICE(obj);
+
+    memory_region_init_io(&s->iomem, obj, &npcm7xx_mft_ops, s,
+                          TYPE_NPCM7XX_MFT, 4 * KiB);
+    sysbus_init_mmio(sbd, &s->iomem);
+    sysbus_init_irq(sbd, &s->irq);
+    s->clock_in = qdev_init_clock_in(dev, "clock-in", npcm7xx_mft_update_clock,
+                                     s, ClockUpdate);
+    s->clock_1 = qdev_init_clock_out(dev, "clock1");
+    s->clock_2 = qdev_init_clock_out(dev, "clock2");
+
+    for (int i = 0; i < NPCM7XX_PWM_PER_MODULE; ++i) {
+        object_property_add(obj, "max_rpm[*]", "uint32",
+                            npcm7xx_mft_get_max_rpm,
+                            npcm7xx_mft_set_max_rpm,
+                            NULL, &s->max_rpm[i]);
+    }
+    qdev_init_gpio_in_named(dev, npcm7xx_mft_duty_handler, "duty",
+                            NPCM7XX_MFT_FANIN_COUNT);
+}
+
+static const VMStateDescription vmstate_npcm7xx_mft = {
+    .name = "npcm7xx-mft-module",
+    .version_id = 0,
+    .minimum_version_id = 0,
+    .fields = (VMStateField[]) {
+        VMSTATE_CLOCK(clock_in, NPCM7xxMFTState),
+        VMSTATE_CLOCK(clock_1, NPCM7xxMFTState),
+        VMSTATE_CLOCK(clock_2, NPCM7xxMFTState),
+        VMSTATE_UINT16_ARRAY(regs, NPCM7xxMFTState, NPCM7XX_MFT_NR_REGS),
+        VMSTATE_UINT32_ARRAY(max_rpm, NPCM7xxMFTState, NPCM7XX_MFT_FANIN_COUNT),
+        VMSTATE_UINT32_ARRAY(duty, NPCM7xxMFTState, NPCM7XX_MFT_FANIN_COUNT),
+        VMSTATE_END_OF_LIST(),
+    },
+};
+
+static void npcm7xx_mft_class_init(ObjectClass *klass, void *data)
+{
+    ResettableClass *rc = RESETTABLE_CLASS(klass);
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->desc = "NPCM7xx MFT Controller";
+    dc->vmsd = &vmstate_npcm7xx_mft;
+    rc->phases.enter = npcm7xx_mft_enter_reset;
+    rc->phases.hold = npcm7xx_mft_hold_reset;
+}
+
+static const TypeInfo npcm7xx_mft_info = {
+    .name               = TYPE_NPCM7XX_MFT,
+    .parent             = TYPE_SYS_BUS_DEVICE,
+    .instance_size      = sizeof(NPCM7xxMFTState),
+    .class_init         = npcm7xx_mft_class_init,
+    .instance_init      = npcm7xx_mft_init,
+};
+
+static void npcm7xx_mft_register_type(void)
+{
+    type_register_static(&npcm7xx_mft_info);
+}
+type_init(npcm7xx_mft_register_type);
diff --git a/hw/misc/trace-events b/hw/misc/trace-events
index cae0055..b87d0b4 100644
--- a/hw/misc/trace-events
+++ b/hw/misc/trace-events
@@ -116,6 +116,14 @@ npcm7xx_clk_write(uint64_t offset, uint32_t value) "offset: 0x%04" PRIx64 " valu
 npcm7xx_gcr_read(uint64_t offset, uint32_t value) " offset: 0x%04" PRIx64 " value: 0x%08" PRIx32
 npcm7xx_gcr_write(uint64_t offset, uint32_t value) "offset: 0x%04" PRIx64 " value: 0x%08" PRIx32
 
+# npcm7xx_mft.c
+npcm7xx_mft_read(const char *name, uint64_t offset, uint16_t value) "%s: offset: 0x%04" PRIx64 " value: 0x%04" PRIx16
+npcm7xx_mft_write(const char *name, uint64_t offset, uint16_t value) "%s: offset: 0x%04" PRIx64 " value: 0x%04" PRIx16
+npcm7xx_mft_rpm(const char *clock, uint32_t clock_hz, int state, int32_t cnt, uint32_t rpm, uint32_t duty) " fan clk: %s clock_hz: %" PRIu32 ", state: %d, cnt: %" PRIi32 ", rpm: %" PRIu32 ", duty: %" PRIu32
+npcm7xx_mft_capture(const char *name, int irq_level) "%s: level: %d"
+npcm7xx_mft_update_clock(const char *name, uint16_t sel, uint64_t clock_period, uint64_t prescaled_clock_period) "%s: sel: 0x%02" PRIx16 ", period: %" PRIu64 ", prescaled: %" PRIu64
+npcm7xx_mft_set_duty(const char *name, int n, int value) "%s[%d]: %d"
+
 # npcm7xx_rng.c
 npcm7xx_rng_read(uint64_t offset, uint64_t value, unsigned size) "offset: 0x%04" PRIx64 " value: 0x%02" PRIx64 " size: %u"
 npcm7xx_rng_write(uint64_t offset, uint64_t value, unsigned size) "offset: 0x%04" PRIx64 " value: 0x%02" PRIx64 " size: %u"
diff --git a/include/hw/misc/npcm7xx_mft.h b/include/hw/misc/npcm7xx_mft.h
new file mode 100644
index 0000000..36785e3
--- /dev/null
+++ b/include/hw/misc/npcm7xx_mft.h
@@ -0,0 +1,70 @@
+/*
+ * Nuvoton NPCM7xx MFT Module
+ *
+ * Copyright 2021 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_MFT_H
+#define NPCM7XX_MFT_H
+
+#include "exec/memory.h"
+#include "hw/clock.h"
+#include "hw/irq.h"
+#include "hw/sysbus.h"
+#include "qom/object.h"
+
+/* Max Fan input number. */
+#define NPCM7XX_MFT_MAX_FAN_INPUT 19
+
+/*
+ * Number of registers in one MFT module. Don't change this without increasing
+ * the version_id in vmstate.
+ */
+#define NPCM7XX_MFT_NR_REGS (0x20 / sizeof(uint16_t))
+
+/*
+ * The MFT can take up to 4 inputs: A0, B0, A1, B1. It can measure one A and one
+ * B simultaneously. NPCM7XX_MFT_INASEL and NPCM7XX_MFT_INBSEL are used to
+ * select which A or B input are used.
+ */
+#define NPCM7XX_MFT_FANIN_COUNT 4
+
+/**
+ * struct NPCM7xxMFTState - Multi Functional Tachometer device state.
+ * @parent: System bus device.
+ * @iomem: Memory region through which registers are accessed.
+ * @clock_in: The input clock for MFT from CLK module.
+ * @clock_{1,2}: The counter clocks for NPCM7XX_MFT_CNT{1,2}
+ * @irq: The IRQ for this MFT state.
+ * @regs: The MMIO registers.
+ * @max_rpm: The maximum rpm for fans. Order: A0, B0, A1, B1.
+ * @duty: The duty cycles for fans, relative to NPCM7XX_PWM_MAX_DUTY.
+ */
+typedef struct NPCM7xxMFTState {
+    SysBusDevice parent;
+
+    MemoryRegion iomem;
+
+    Clock       *clock_in;
+    Clock       *clock_1, *clock_2;
+    qemu_irq    irq;
+    uint16_t    regs[NPCM7XX_MFT_NR_REGS];
+
+    uint32_t    max_rpm[NPCM7XX_MFT_FANIN_COUNT];
+    uint32_t    duty[NPCM7XX_MFT_FANIN_COUNT];
+} NPCM7xxMFTState;
+
+#define TYPE_NPCM7XX_MFT "npcm7xx-mft"
+#define NPCM7XX_MFT(obj) \
+    OBJECT_CHECK(NPCM7xxMFTState, (obj), TYPE_NPCM7XX_MFT)
+
+#endif /* NPCM7XX_MFT_H */