hw/adc: Add an ADC module for NPCM7XX

The ADC is part of NPCM7XX Module. Its behavior is controled by the
ADC_CON register. It converts one of the eight analog inputs into a
digital input and stores it in the ADC_DATA register when enabled.

Users can alter input value by using qom-set QMP command.

Reviewed-by: Havard Skinnemoen <hskinnemoen@google.com>
Reviewed-by: Tyrone Ting <kfting@nuvoton.com>
Signed-off-by: Hao Wu <wuhaotsh@google.com>
Message-id: 20210108190945.949196-4-wuhaotsh@google.com
[PMM: Added missing hw/adc/trace.h file]
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

4 files changed, 308 insertions, 0 deletions

diff --git a/hw/adc/meson.build b/hw/adc/meson.build
index 0d62ae96ae..6ddee23813 100644
--- a/hw/adc/meson.build
+++ b/hw/adc/meson.build
@@ -1 +1,2 @@
 softmmu_ss.add(when: 'CONFIG_STM32F2XX_ADC', if_true: files('stm32f2xx_adc.c'))
+softmmu_ss.add(when: 'CONFIG_NPCM7XX', if_true: files('npcm7xx_adc.c'))
diff --git a/hw/adc/npcm7xx_adc.c b/hw/adc/npcm7xx_adc.c
new file mode 100644
index 0000000000..870a6d50c2
--- /dev/null
+++ b/hw/adc/npcm7xx_adc.c
@@ -0,0 +1,301 @@
+/*
+ * Nuvoton NPCM7xx ADC Module
+ *
+ * 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.
+ */
+
+#include "qemu/osdep.h"
+#include "hw/adc/npcm7xx_adc.h"
+#include "hw/qdev-clock.h"
+#include "hw/qdev-properties.h"
+#include "hw/registerfields.h"
+#include "migration/vmstate.h"
+#include "qemu/log.h"
+#include "qemu/module.h"
+#include "qemu/timer.h"
+#include "qemu/units.h"
+#include "trace.h"
+
+REG32(NPCM7XX_ADC_CON, 0x0)
+REG32(NPCM7XX_ADC_DATA, 0x4)
+
+/* Register field definitions. */
+#define NPCM7XX_ADC_CON_MUX(rv) extract32(rv, 24, 4)
+#define NPCM7XX_ADC_CON_INT_EN  BIT(21)
+#define NPCM7XX_ADC_CON_REFSEL  BIT(19)
+#define NPCM7XX_ADC_CON_INT     BIT(18)
+#define NPCM7XX_ADC_CON_EN      BIT(17)
+#define NPCM7XX_ADC_CON_RST     BIT(16)
+#define NPCM7XX_ADC_CON_CONV    BIT(14)
+#define NPCM7XX_ADC_CON_DIV(rv) extract32(rv, 1, 8)
+
+#define NPCM7XX_ADC_MAX_RESULT      1023
+#define NPCM7XX_ADC_DEFAULT_IREF    2000000
+#define NPCM7XX_ADC_CONV_CYCLES     20
+#define NPCM7XX_ADC_RESET_CYCLES    10
+#define NPCM7XX_ADC_R0_INPUT        500000
+#define NPCM7XX_ADC_R1_INPUT        1500000
+
+static void npcm7xx_adc_reset(NPCM7xxADCState *s)
+{
+    timer_del(&s->conv_timer);
+    s->con = 0x000c0001;
+    s->data = 0x00000000;
+}
+
+static uint32_t npcm7xx_adc_convert(uint32_t input, uint32_t ref)
+{
+    uint32_t result;
+
+    result = input * (NPCM7XX_ADC_MAX_RESULT + 1) / ref;
+    if (result > NPCM7XX_ADC_MAX_RESULT) {
+        result = NPCM7XX_ADC_MAX_RESULT;
+    }
+
+    return result;
+}
+
+static uint32_t npcm7xx_adc_prescaler(NPCM7xxADCState *s)
+{
+    return 2 * (NPCM7XX_ADC_CON_DIV(s->con) + 1);
+}
+
+static void npcm7xx_adc_start_timer(Clock *clk, QEMUTimer *timer,
+        uint32_t cycles, uint32_t prescaler)
+{
+    int64_t now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+    int64_t ticks = cycles;
+    int64_t ns;
+
+    ticks *= prescaler;
+    ns = clock_ticks_to_ns(clk, ticks);
+    ns += now;
+    timer_mod(timer, ns);
+}
+
+static void npcm7xx_adc_start_convert(NPCM7xxADCState *s)
+{
+    uint32_t prescaler = npcm7xx_adc_prescaler(s);
+
+    npcm7xx_adc_start_timer(s->clock, &s->conv_timer, NPCM7XX_ADC_CONV_CYCLES,
+            prescaler);
+}
+
+static void npcm7xx_adc_convert_done(void *opaque)
+{
+    NPCM7xxADCState *s = opaque;
+    uint32_t input = NPCM7XX_ADC_CON_MUX(s->con);
+    uint32_t ref = (s->con & NPCM7XX_ADC_CON_REFSEL)
+        ? s->iref : s->vref;
+
+    if (input >= NPCM7XX_ADC_NUM_INPUTS) {
+        qemu_log_mask(LOG_GUEST_ERROR, "%s: invalid input: %u\n",
+                      __func__, input);
+        return;
+    }
+    s->data = npcm7xx_adc_convert(s->adci[input], ref);
+    if (s->con & NPCM7XX_ADC_CON_INT_EN) {
+        s->con |= NPCM7XX_ADC_CON_INT;
+        qemu_irq_raise(s->irq);
+    }
+    s->con &= ~NPCM7XX_ADC_CON_CONV;
+}
+
+static void npcm7xx_adc_calibrate(NPCM7xxADCState *adc)
+{
+    adc->calibration_r_values[0] = npcm7xx_adc_convert(NPCM7XX_ADC_R0_INPUT,
+            adc->iref);
+    adc->calibration_r_values[1] = npcm7xx_adc_convert(NPCM7XX_ADC_R1_INPUT,
+            adc->iref);
+}
+
+static void npcm7xx_adc_write_con(NPCM7xxADCState *s, uint32_t new_con)
+{
+    uint32_t old_con = s->con;
+
+    /* Write ADC_INT to 1 to clear it */
+    if (new_con & NPCM7XX_ADC_CON_INT) {
+        new_con &= ~NPCM7XX_ADC_CON_INT;
+        qemu_irq_lower(s->irq);
+    } else if (old_con & NPCM7XX_ADC_CON_INT) {
+        new_con |= NPCM7XX_ADC_CON_INT;
+    }
+
+    s->con = new_con;
+
+    if (s->con & NPCM7XX_ADC_CON_RST) {
+        npcm7xx_adc_reset(s);
+        return;
+    }
+
+    if ((s->con & NPCM7XX_ADC_CON_EN)) {
+        if (s->con & NPCM7XX_ADC_CON_CONV) {
+            if (!(old_con & NPCM7XX_ADC_CON_CONV)) {
+                npcm7xx_adc_start_convert(s);
+            }
+        } else {
+            timer_del(&s->conv_timer);
+        }
+    }
+}
+
+static uint64_t npcm7xx_adc_read(void *opaque, hwaddr offset, unsigned size)
+{
+    uint64_t value = 0;
+    NPCM7xxADCState *s = opaque;
+
+    switch (offset) {
+    case A_NPCM7XX_ADC_CON:
+        value = s->con;
+        break;
+
+    case A_NPCM7XX_ADC_DATA:
+        value = s->data;
+        break;
+
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: invalid offset 0x%04" HWADDR_PRIx "\n",
+                      __func__, offset);
+        break;
+    }
+
+    trace_npcm7xx_adc_read(DEVICE(s)->canonical_path, offset, value);
+    return value;
+}
+
+static void npcm7xx_adc_write(void *opaque, hwaddr offset, uint64_t v,
+        unsigned size)
+{
+    NPCM7xxADCState *s = opaque;
+
+    trace_npcm7xx_adc_write(DEVICE(s)->canonical_path, offset, v);
+    switch (offset) {
+    case A_NPCM7XX_ADC_CON:
+        npcm7xx_adc_write_con(s, v);
+        break;
+
+    case A_NPCM7XX_ADC_DATA:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: register @ 0x%04" HWADDR_PRIx " is read-only\n",
+                      __func__, offset);
+        break;
+
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: invalid offset 0x%04" HWADDR_PRIx "\n",
+                      __func__, offset);
+        break;
+    }
+
+}
+
+static const struct MemoryRegionOps npcm7xx_adc_ops = {
+    .read       = npcm7xx_adc_read,
+    .write      = npcm7xx_adc_write,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+    .valid      = {
+        .min_access_size        = 4,
+        .max_access_size        = 4,
+        .unaligned              = false,
+    },
+};
+
+static void npcm7xx_adc_enter_reset(Object *obj, ResetType type)
+{
+    NPCM7xxADCState *s = NPCM7XX_ADC(obj);
+
+    npcm7xx_adc_reset(s);
+}
+
+static void npcm7xx_adc_hold_reset(Object *obj)
+{
+    NPCM7xxADCState *s = NPCM7XX_ADC(obj);
+
+    qemu_irq_lower(s->irq);
+}
+
+static void npcm7xx_adc_init(Object *obj)
+{
+    NPCM7xxADCState *s = NPCM7XX_ADC(obj);
+    SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
+    int i;
+
+    sysbus_init_irq(sbd, &s->irq);
+
+    timer_init_ns(&s->conv_timer, QEMU_CLOCK_VIRTUAL,
+            npcm7xx_adc_convert_done, s);
+    memory_region_init_io(&s->iomem, obj, &npcm7xx_adc_ops, s,
+                          TYPE_NPCM7XX_ADC, 4 * KiB);
+    sysbus_init_mmio(sbd, &s->iomem);
+    s->clock = qdev_init_clock_in(DEVICE(s), "clock", NULL, NULL);
+
+    for (i = 0; i < NPCM7XX_ADC_NUM_INPUTS; ++i) {
+        object_property_add_uint32_ptr(obj, "adci[*]",
+                &s->adci[i], OBJ_PROP_FLAG_WRITE);
+    }
+    object_property_add_uint32_ptr(obj, "vref",
+            &s->vref, OBJ_PROP_FLAG_WRITE);
+    npcm7xx_adc_calibrate(s);
+}
+
+static const VMStateDescription vmstate_npcm7xx_adc = {
+    .name = "npcm7xx-adc",
+    .version_id = 0,
+    .minimum_version_id = 0,
+    .fields = (VMStateField[]) {
+        VMSTATE_TIMER(conv_timer, NPCM7xxADCState),
+        VMSTATE_UINT32(con, NPCM7xxADCState),
+        VMSTATE_UINT32(data, NPCM7xxADCState),
+        VMSTATE_CLOCK(clock, NPCM7xxADCState),
+        VMSTATE_UINT32_ARRAY(adci, NPCM7xxADCState, NPCM7XX_ADC_NUM_INPUTS),
+        VMSTATE_UINT32(vref, NPCM7xxADCState),
+        VMSTATE_UINT32(iref, NPCM7xxADCState),
+        VMSTATE_UINT16_ARRAY(calibration_r_values, NPCM7xxADCState,
+                NPCM7XX_ADC_NUM_CALIB),
+        VMSTATE_END_OF_LIST(),
+    },
+};
+
+static Property npcm7xx_timer_properties[] = {
+    DEFINE_PROP_UINT32("iref", NPCM7xxADCState, iref, NPCM7XX_ADC_DEFAULT_IREF),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void npcm7xx_adc_class_init(ObjectClass *klass, void *data)
+{
+    ResettableClass *rc = RESETTABLE_CLASS(klass);
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->desc = "NPCM7xx ADC Module";
+    dc->vmsd = &vmstate_npcm7xx_adc;
+    rc->phases.enter = npcm7xx_adc_enter_reset;
+    rc->phases.hold = npcm7xx_adc_hold_reset;
+
+    device_class_set_props(dc, npcm7xx_timer_properties);
+}
+
+static const TypeInfo npcm7xx_adc_info = {
+    .name               = TYPE_NPCM7XX_ADC,
+    .parent             = TYPE_SYS_BUS_DEVICE,
+    .instance_size      = sizeof(NPCM7xxADCState),
+    .class_init         = npcm7xx_adc_class_init,
+    .instance_init      = npcm7xx_adc_init,
+};
+
+static void npcm7xx_adc_register_types(void)
+{
+    type_register_static(&npcm7xx_adc_info);
+}
+
+type_init(npcm7xx_adc_register_types);
diff --git a/hw/adc/trace-events b/hw/adc/trace-events
new file mode 100644
index 0000000000..4c3279ece2
--- /dev/null
+++ b/hw/adc/trace-events
@@ -0,0 +1,5 @@
+# See docs/devel/tracing.txt for syntax documentation.
+
+# npcm7xx_adc.c
+npcm7xx_adc_read(const char *id, uint64_t offset, uint32_t value) " %s offset: 0x%04" PRIx64 " value 0x%04" PRIx32
+npcm7xx_adc_write(const char *id, uint64_t offset, uint32_t value) "%s offset: 0x%04" PRIx64 " value 0x%04" PRIx32
diff --git a/hw/adc/trace.h b/hw/adc/trace.h
new file mode 100644
index 0000000000..b71d5b5b4e
--- /dev/null
+++ b/hw/adc/trace.h
@@ -0,0 +1 @@
+#include "trace/trace-hw_adc.h"