Hi Alastair,

Again, small comments below.

On Thu, 2016-12-15 at 16:48 +1100, Alastair D'Silva wrote:
> > From: Alastair D'Silva <alastair@d-silva.org>
> 
> > Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
> ---
>  tests/Makefile.include |   2 +
>  tests/rx8900-test.c    | 882 +++++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 884 insertions(+)
>  create mode 100644 tests/rx8900-test.c
> 
> diff --git a/tests/Makefile.include b/tests/Makefile.include
> index e98d3b6..e52e355 100644
> --- a/tests/Makefile.include
> +++ b/tests/Makefile.include
> @@ -300,6 +300,7 @@ check-qtest-sparc64-y = tests/endianness-test$(EXESUF)
>  
>  check-qtest-arm-y = tests/tmp105-test$(EXESUF)
>  check-qtest-arm-y += tests/ds1338-test$(EXESUF)
> +check-qtest-arm-y += tests/rx8900-test$(EXESUF)
>  check-qtest-arm-y += tests/m25p80-test$(EXESUF)
>  gcov-files-arm-y += hw/misc/tmp105.c
>  check-qtest-arm-y += tests/virtio-blk-test$(EXESUF)
> @@ -637,6 +638,7 @@ tests/bios-tables-test$(EXESUF): tests/bios-tables-test.o \
>  tests/pxe-test$(EXESUF): tests/pxe-test.o tests/boot-sector.o $(libqos-obj-y)
>  tests/tmp105-test$(EXESUF): tests/tmp105-test.o $(libqos-omap-obj-y)
>  tests/ds1338-test$(EXESUF): tests/ds1338-test.o $(libqos-imx-obj-y)
> +tests/rx8900-test$(EXESUF): tests/rx8900-test.o $(libqos-imx-obj-y)
>  tests/m25p80-test$(EXESUF): tests/m25p80-test.o
>  tests/i440fx-test$(EXESUF): tests/i440fx-test.o $(libqos-pc-obj-y)
>  tests/q35-test$(EXESUF): tests/q35-test.o $(libqos-pc-obj-y)
> diff --git a/tests/rx8900-test.c b/tests/rx8900-test.c
> new file mode 100644
> index 0000000..1769659
> --- /dev/null
> +++ b/tests/rx8900-test.c
> @@ -0,0 +1,882 @@
> +/*
> + * QTest testcase for the Epson RX8900SA/CE RTC
> + *
> + * Copyright (c) 2016 IBM Corporation
> + * Authors:
> > + *  Alastair D'Silva <alastair@d-silva.org>
> + *
> + * This code is licensed under the GPL version 2 or later.  See
> + * the COPYING file in the top-level directory.
> + */
> +
> +#include "qemu/osdep.h"
> +#include "hw/timer/rx8900_regs.h"
> +#include "libqtest.h"
> +#include "libqos/i2c.h"
> +#include "qemu/timer.h"
> +
> +#define IMX25_I2C_0_BASE 0x43F80000
> +#define RX8900_TEST_ID "rx8900-test"
> +#define RX8900_ADDR 0x32
> +#define RX8900_INTERRUPT_OUT "rx8900-interrupt-out"
> +#define RX8900_FOUT_ENABLE "rx8900-fout-enable"
> +#define RX8900_FOUT "rx8900-fout"
> +
> +static I2CAdapter *i2c;
> +static uint8_t addr;
> +
> +static inline uint8_t bcd2bin(uint8_t x)
> +{
> +    return (x & 0x0f) + (x >> 4) * 10;
> +}
> +
> +static inline uint8_t bin2bcd(uint8_t x)
> +{
> +    return (x / 10 << 4) | (x % 10);
> +}
> +
> +static void qmp_rx8900_set_temperature(const char *id, double value)
> +{
> +    QDict *response;
> +
> +    response = qmp("{ 'execute': 'qom-set', 'arguments': { 'path': %s, "
> +                   "'property': 'temperature', 'value': %f } }", id, value);
> +    g_assert(qdict_haskey(response, "return"));
> +    QDECREF(response);
> +}
> +
> +static void qmp_rx8900_set_voltage(const char *id, double value)
> +{
> +    QDict *response;
> +
> +    response = qmp("{ 'execute': 'qom-set', 'arguments': { 'path': %s, "
> +                   "'property': 'voltage', 'value': %f } }", id, value);
> +    g_assert(qdict_haskey(response, "return"));
> +    QDECREF(response);
> +}
> +
> +/**
> + * Read an RX8900 register
> + * @param reg the address of the register
> + * @return the value of the register
> + */
> +static uint8_t read_register(RX8900Addresses reg)
> +{
> +    uint8_t val;
> +    uint8_t reg_address = (uint8_t)reg;
> +
> +    i2c_send(i2c, addr, &reg_address, 1);
> +    i2c_recv(i2c, addr, &val, 1);
> +
> +    return val;
> +}
> +
> +/**
> + * Write to an RX8900 register
> + * @param reg the address of the register
> + * @param val the value to write
> + */
> +static uint8_t write_register(RX8900Addresses reg, uint8_t val)
> +{
> +    uint8_t buf[2];
> +
> +    buf[0] = reg;
> +    buf[1] = val;
> +
> +    i2c_send(i2c, addr, buf, 2);
> +
> +    return val;
> +}
> +
> +/**
> + * Set bits in a register
> + * @param reg the address of the register
> + * @param mask a mask of the bits to set
> + */
> +static void set_bits_in_register(RX8900Addresses reg, uint8_t mask)
> +{
> +    uint8_t value = read_register(reg);
> +    value |= mask;
> +    write_register(reg, value);
> +}
> +
> +/**
> + * Clear bits in a register
> + * @param reg the address of the register
> + * @param mask a mask of the bits to set
> + */
> +static void clear_bits_in_register(RX8900Addresses reg, uint8_t mask)
> +{
> +    uint8_t value = read_register(reg);
> +    value &= ~mask;
> +    write_register(reg, value);
> +}
> +
> +/**
> + * Read a number of sequential RX8900 registers
> + * @param reg the address of the first register
> + * @param buf (out) an output buffer to stash the register values
> + * @param count the number of registers to read
> + */
> +static void read_registers(RX8900Addresses reg, uint8_t *buf, uint8_t count)
> +{
> +    uint8_t reg_address = (uint8_t)reg;
> +
> +    i2c_send(i2c, addr, &reg_address, 1);
> +    i2c_recv(i2c, addr, buf, count);
> +}
> +
> +/**
> + * Write to a sequential number of RX8900 registers
> + * @param reg the address of the first register
> + * @param buffer a buffer of values to write
> + * @param count the sumber of registers to write
> + */
> +static void write_registers(RX8900Addresses reg, uint8_t *buffer, uint8_t count)
> +{
> +    uint8_t buf[RX8900_NVRAM_SIZE + 1];
> +
> +    buf[0] = (uint8_t)reg;
> +    memcpy(buf + 1, buffer, count);
> +
> +    i2c_send(i2c, addr, buf, count + 1);
> +}
> +
> +/**
> + * Set the time on the RX8900
> + * @param secs the seconds to set
> + * @param mins the minutes to set
> + * @param hours the hours to set
> + * @param weekday the day of the week to set (0 = Sunday)
> + * @param day the day of the month to set
> + * @param month the month to set
> + * @param year the year to set
> + */
> +static void set_time(uint8_t secs, uint8_t mins, uint8_t hours,
> +        uint8_t weekday, uint8_t day, uint8_t month, uint8_t year)
> +{
> +    uint8_t buf[7];
> +
> +    buf[0] = bin2bcd(secs);
> +    buf[1] = bin2bcd(mins);
> +    buf[2] = bin2bcd(hours);
> +    buf[3] = BIT(weekday);
> +    buf[4] = bin2bcd(day);
> +    buf[5] = bin2bcd(month);
> +    buf[6] = bin2bcd(year);
> +
> +    write_registers(SECONDS, buf, 7);
> +}
> +
> +
> +/**
> + * Check basic communication
> + */
> +static void send_and_receive(void)
> +{
> +    uint8_t buf[7];
> +    time_t now = time(NULL);
> +    struct tm *tm_ptr;
> +
> +    /* retrieve the date */
> +    read_registers(SECONDS, buf, 7);
> +
> +    tm_ptr = gmtime(&now);
> +
> +    /* check retrieved time against local time */
> +    g_assert_cmpuint(bcd2bin(buf[0]), == , tm_ptr->tm_sec);
> +    g_assert_cmpuint(bcd2bin(buf[1]), == , tm_ptr->tm_min);
> +    g_assert_cmpuint(bcd2bin(buf[2]), == , tm_ptr->tm_hour);
> +    g_assert_cmpuint(bcd2bin(buf[4]), == , tm_ptr->tm_mday);
> +    g_assert_cmpuint(bcd2bin(buf[5]), == , 1 + tm_ptr->tm_mon);
> +    g_assert_cmpuint(2000 + bcd2bin(buf[6]), == , 1900 + tm_ptr->tm_year);
> +}
> +
> +/**
> + * Check that the temperature can be altered via properties
> + */
> +static void check_temperature(void)
> +{
> +   /* Check the initial temperature is 25C */
> +    uint8_t temperature;
> +
> +    temperature = read_register(TEMPERATURE);
> +    g_assert_cmpuint(temperature, == , 133);
> +
> +    /* Set the temperature to 40C and check the temperature again */
> +    qmp_rx8900_set_temperature(RX8900_TEST_ID, 40.0f);
> +    temperature = read_register(TEMPERATURE);
> +    g_assert_cmpuint(temperature, == , 157);
> +}
> +
> +/**
> + * Check that the time rolls over correctly
> + */
> +static void check_rollover(void)
> +{
> +    uint8_t buf[7];
> +
> +
> +    set_time(59, 59, 23, 1, 29, 2, 16);
> +
> +    /* Wait for the clock to rollover */
> +    sleep(2);
> 

Can we control time some other way so we're not delaying the test
suite? I assume not?

> +
> +    memset(buf, 0, sizeof(buf));
> +
> +    /* Check that the clock rolled over */
> +    /* Read from registers starting at 0x00 */
> +    buf[0] = 0x00;
> +
> +    read_registers(SECONDS, buf, 7);
> +
> +    /* Ignore seconds as there may be some noise,
> +     * we expect 00:00:xx Tuesday 1/3/2016
> +     */

this is why it would be nice if we could control time.

> +    g_assert_cmpuint(bcd2bin(buf[1]), == , 0);
> +    g_assert_cmpuint(bcd2bin(buf[2]), == , 0);
> +    g_assert_cmpuint(bcd2bin(buf[3]), == , 0x04);
> +    g_assert_cmpuint(bcd2bin(buf[4]), == , 1);
> +    g_assert_cmpuint(bcd2bin(buf[5]), == , 3);
> +    g_assert_cmpuint(bcd2bin(buf[6]), == , 16);
> +}
> +
> +uint32_t interrupt_counts[RX8900_INTERRUPT_SOURCES];
> +
> +/**
> + * Reset the interrupt counts
> + */
> +static void count_reset(void)
> +{
> +    for (int source = 0; source < RX8900_INTERRUPT_SOURCES; source++) {
> +        interrupt_counts[source] = 0;
> +    }
> +}
> +
> +/**
> + * Handle an RX8900 interrupt (update the counts for that interrupt type)
> + */
> +static void handle_interrupt(void *opaque, const char *name, int irq,
> +        bool level)
> +{
> +    if (!level) {
> +        return;
> +    }
> +
> +    uint8_t flags = read_register(FLAG_REGISTER);
> +
> +    for (int flag = 0; flag < 8; flag++) {
> +        if (flags & BIT(flag)) {
> +            interrupt_counts[flag]++;
> +        }
> +    }
> +
> +    write_register(FLAG_REGISTER, 0x00);
> +}
> +
> +uint32_t fout_counts;
> +
> +/**
> + * Handle an Fout state change
> + */
> +static void handle_fout(void *opaque, const char *name, int irq, bool level)
> +{
> +    if (!level) {
> +        return;
> +    }
> +
> +    fout_counts++;
> +}
> +
> +/**
> + * Reset the fout count
> + */
> +static void fout_count_reset(void)
> +{
> +    fout_counts = 0;
> +}
> +
> +
> +/**
> + * Sleep for some real time while counting interrupts
> + * @param delay the delay in microseconds
> + * @param loop the loop time in microseconds
> + */
> +static void wait_for(uint64_t delay, uint64_t loop)
> +{
> +    struct timeval end, now;
> +
> +    gettimeofday(&end, NULL);
> +    delay += end.tv_usec;
> +    end.tv_sec += delay / 1000000;
> +    end.tv_usec = delay % 1000000;

I think we should use timeradd() here, as this might be out by part of
a second.

> +
> +    while (gettimeofday(&now, NULL),
> +            now.tv_sec < end.tv_sec || now.tv_usec < end.tv_usec) {

This condition is a little clever and also buggy. You'll at least need
something like:

    while(gettimeofday(&now, NULL),
            now.tv_sec < end.tv_sec ||
            now.tv_sec == end.tv_sec && now.tv_usec < end.tv_usec) { ... }

Depending on the value of loop you may wind up in the position where 
now.tv_usec < end.tv_usec is true for multiple loops beyond now.tv_sec
< end.tv_sec failing with the case now.tv_sec > end.tv_sec.

But you should probably use timercmp().

> +        clock_step(loop * 1000);
> +        usleep(loop);
> +    }
> +}
> +
> +/**
> + * Sleep for some emulated time while counting interrupts
> + * @param delay the delay in nanoseconds
> + * @param loop the loop time in nanoseconds
> + */
> +static void wait_cycles(uint64_t delay, uint64_t loop)
> +{
> +    uint64_t counter;
> +
> +    for (counter = 0; counter < delay; counter += loop) {
> +        clock_step(loop);
> +    }
> +}
> +
> +
> +/**
> + * Check that when the update timer interrupt is disabled, that no interrupts
> + * occur
> + */
> +static void check_update_interrupt_disabled(void)
> +{
> +    /* Disable the update interrupt */
> +    clear_bits_in_register(CONTROL_REGISTER, CTRL_MASK_UIE);
> +
> +    /* Wait for the clock to rollover, this will cover both seconds & minutes
> +     */
> +    set_time(59, 59, 23, 1, 29, 2, 16);
> +
> +    count_reset();
> +    wait_for(2 * 1000000, 1000);
> +
> +    g_assert_cmpuint(interrupt_counts[FLAG_REG_UF], ==, 0);
> +    g_assert_cmpuint(interrupt_counts[FLAG_REG_AF], ==, 0);
> +}
> +
> +
> +/**
> + * Check that when the update timer interrupt is enabled and configured for
> + * per second updates, that we get the appropriate number of interrupts
> + */
> +static void check_update_interrupt_seconds(void)
> +{
> +    set_time(59, 59, 23, 1, 29, 2, 16);
> +
> +    /* Enable the update interrupt for per second updates */
> +    clear_bits_in_register(EXTENSION_REGISTER, EXT_MASK_USEL);
> +    set_bits_in_register(CONTROL_REGISTER, CTRL_MASK_UIE);
> +
> +    count_reset();
> +    wait_for(5.1f * 1000000ULL, 1000);
> +
> +    /* Disable the update interrupt */
> +    clear_bits_in_register(CONTROL_REGISTER, CTRL_MASK_UIE);
> +
> +    g_assert_cmpuint(interrupt_counts[FLAG_REG_UF], >=, 5);
> +    g_assert_cmpuint(interrupt_counts[FLAG_REG_UF], <=, 6);
> +    g_assert_cmpuint(interrupt_counts[FLAG_REG_AF], ==, 0);
> +}
> +
> +/**
> + * Check that when the update timer interrupt is enabled and configured for
> + * per minute updates, that we get the appropriate number of interrupts
> + */
> +static void check_update_interrupt_minutes(void)
> +{
> +    set_time(59, 59, 23, 1, 29, 2, 16);
> +
> +    /* Enable the update interrupt for per minute updates */
> +    set_bits_in_register(EXTENSION_REGISTER, EXT_MASK_USEL);
> +    set_bits_in_register(CONTROL_REGISTER, CTRL_MASK_UIE);
> +
> +    count_reset();
> +    wait_for(5 * 1000000ULL, 1000);
> +
> +    /* Disable the update interrupt */
> +    clear_bits_in_register(CONTROL_REGISTER, CTRL_MASK_UIE);
> +
> +    g_assert_cmpuint(interrupt_counts[FLAG_REG_UF], ==, 1);
> +    g_assert_cmpuint(interrupt_counts[FLAG_REG_AF], ==, 0);
> +}
> +
> +
> +/**
> + * Check that when the alarm timer interrupt is disabled, that no interrupts
> + * occur
> + */
> +static void check_alarm_interrupt_disabled(void)
> +{
> +    /* Disable the alarm interrupt */
> +    clear_bits_in_register(CONTROL_REGISTER, CTRL_MASK_AIE);
> +
> +    /* Set an alarm for midnight */
> +    uint8_t buf[3];
> +
> +    buf[0] = bin2bcd(0); /* minutes */
> +    buf[1] = bin2bcd(0); /* hours */
> +    buf[2] = bin2bcd(1); /* day */
> +
> +    write_registers(ALARM_MINUTE, buf, 3);
> +
> +    /* Wait for the clock to rollover */
> +    set_time(59, 59, 23, 1, 29, 2, 16);
> +
> +    count_reset();
> +    wait_for(2 * 1000000, 1000);
> +
> +    g_assert_cmpuint(interrupt_counts[FLAG_REG_UF], ==, 0);
> +    g_assert_cmpuint(interrupt_counts[FLAG_REG_AF], ==, 0);
> +}
> +
> +/**
> + * Check that when the alarm timer interrupt is enabled, that an interrupt
> + * occurs
> + */
> +static void check_alarm_interrupt_day_of_month(void)
> +{
> +
> +    /* Set an alarm for midnight */
> +    uint8_t buf[3];
> +
> +    buf[0] = bin2bcd(0); /* minutes */
> +    buf[1] = bin2bcd(0); /* hours */
> +    buf[2] = bin2bcd(1); /* day */
> +
> +    write_registers(ALARM_MINUTE, buf, 3);
> +
> +    /* Set alarm to day of month mode */
> +    set_bits_in_register(EXTENSION_REGISTER, EXT_MASK_WADA);
> +
> +    /* Enable the alarm interrupt */
> +    set_bits_in_register(CONTROL_REGISTER, CTRL_MASK_AIE);
> +
> +    /* Wait for the clock to rollover */
> +    set_time(59, 59, 23, 1, 29, 2, 16);
> +
> +    count_reset();
> +    wait_for(2 * 1000000, 1000);
> +
> +    /* Disable the alarm interrupt */
> +    clear_bits_in_register(CONTROL_REGISTER, CTRL_MASK_AIE);
> +
> +    g_assert_cmpuint(interrupt_counts[FLAG_REG_UF], ==, 0);
> +    g_assert_cmpuint(interrupt_counts[FLAG_REG_AF], ==, 1);
> +}
> +
> +/**
> + * Check that when the alarm timer interrupt is enabled, that an interrupt
> + * does not occur
> + */
> +static void check_alarm_interrupt_day_of_month_negative(void)
> +{
> +
> +    /* Set an alarm for midnight */
> +    uint8_t buf[3];
> +
> +    buf[0] = bin2bcd(0); /* minutes */
> +    buf[1] = bin2bcd(0); /* hours */
> +    buf[2] = bin2bcd(2); /* day */
> +
> +    write_registers(ALARM_MINUTE, buf, 3);
> +
> +    /* Set alarm to day of month mode */
> +    set_bits_in_register(EXTENSION_REGISTER, EXT_MASK_WADA);
> +
> +    /* Enable the alarm interrupt */
> +    set_bits_in_register(CONTROL_REGISTER, CTRL_MASK_AIE);
> +
> +    /* Wait for the clock to rollover */
> +    set_time(59, 59, 23, 1, 29, 2, 16);
> +
> +    count_reset();
> +    wait_for(2 * 1000000, 1000);
> +
> +    /* Disable the alarm interrupt */
> +    clear_bits_in_register(CONTROL_REGISTER, CTRL_MASK_AIE);
> +
> +    g_assert_cmpuint(interrupt_counts[FLAG_REG_UF], ==, 0);
> +    g_assert_cmpuint(interrupt_counts[FLAG_REG_AF], ==, 0);
> +}
> +
> +/**
> + * Check that when the alarm timer interrupt is enabled, that an interrupt
> + * occurs
> + */
> +static void check_alarm_interrupt_day_of_week(void)
> +{
> +
> +    /* Set an alarm for midnight */
> +    uint8_t buf[3];
> +
> +    buf[0] = bin2bcd(0); /* minutes */
> +    buf[1] = bin2bcd(0); /* hours */
> +    buf[2] = 0x01 << 2; /* day */
> +
> +    write_registers(ALARM_MINUTE, buf, 3);
> +
> +    /* Set alarm to day of week mode */
> +    clear_bits_in_register(EXTENSION_REGISTER, EXT_MASK_WADA);
> +
> +    /* Enable the alarm interrupt */
> +    set_bits_in_register(CONTROL_REGISTER, CTRL_MASK_AIE);
> +
> +    /* Wait for the clock to rollover */
> +    set_time(59, 59, 23, 1, 29, 2, 16);
> +
> +    count_reset();
> +    wait_for(2 * 1000000, 1000);
> +
> +    /* Disable the alarm interrupt */
> +    clear_bits_in_register(CONTROL_REGISTER, CTRL_MASK_AIE);
> +
> +    g_assert_cmpuint(interrupt_counts[FLAG_REG_UF], ==, 0);
> +    g_assert_cmpuint(interrupt_counts[FLAG_REG_AF], ==, 1);
> +}
> +
> +/**
> + * Check that when the alarm timer interrupt is enabled, that an interrupt
> + * does not occur
> + */
> +static void check_alarm_interrupt_day_of_week_negative(void)
> +{
> +
> +    /* Set an alarm for midnight */
> +    uint8_t buf[3];
> +
> +    buf[0] = bin2bcd(0); /* minutes */
> +    buf[1] = bin2bcd(0); /* hours */
> +    buf[2] = 0x01 << 2; /* day */
> +
> +    write_registers(ALARM_MINUTE, buf, 3);
> +
> +    /* Set alarm to day of week mode */
> +    clear_bits_in_register(EXTENSION_REGISTER, EXT_MASK_WADA);
> +
> +    /* Enable the alarm interrupt */
> +    set_bits_in_register(CONTROL_REGISTER, CTRL_MASK_AIE);
> +
> +    /* Wait for the clock to rollover */
> +    set_time(59, 59, 23, 3, 29, 2, 16);
> +
> +    count_reset();
> +    wait_for(2 * 1000000, 1000);
> +
> +    /* Disable the alarm interrupt */
> +    clear_bits_in_register(CONTROL_REGISTER, CTRL_MASK_AIE);
> +
> +    g_assert_cmpuint(interrupt_counts[FLAG_REG_UF], ==, 0);
> +    g_assert_cmpuint(interrupt_counts[FLAG_REG_AF], ==, 0);
> +}
> +
> +/**
> + * Check that the reset function
> + */
> +static void check_reset(void)
> +{
> +    set_bits_in_register(FLAG_REGISTER, FLAG_MASK_UF);
> +    set_bits_in_register(CONTROL_REGISTER, CTRL_MASK_RESET);
> +
> +    g_assert_cmpuint(read_register(FLAG_REGISTER), ==,
> +            0x00);
> +}
> +
> +/**
> + * Check that Fout operates at 1Hz
> + */
> +static void check_fout_1hz(void)
> +{
> +    uint8_t ext_reg = read_register(EXTENSION_REGISTER);
> +    ext_reg |= EXT_MASK_FSEL1;
> +    ext_reg &= ~EXT_MASK_FSEL0;
> +    write_register(EXTENSION_REGISTER, ext_reg);
> +
> +    /* Enable Fout */
> +    irq_set(RX8900_TEST_ID, RX8900_FOUT_ENABLE, 0, true);
> +
> +    fout_count_reset();
> +    wait_cycles(2 * 1000000000ULL, 1000000);
> +
> +    /* disable Fout */
> +    irq_set(RX8900_TEST_ID, RX8900_FOUT_ENABLE, 0, false);
> +
> +    g_assert_cmpuint(fout_counts, ==, 2);
> +}
> +
> +/**
> + * Check that Fout operates at 1024Hz
> + */
> +static void check_fout_1024hz(void)
> +{
> +    uint8_t ext_reg = read_register(EXTENSION_REGISTER);
> +    ext_reg |= EXT_MASK_FSEL0;
> +    ext_reg &= ~EXT_MASK_FSEL1;
> +    write_register(EXTENSION_REGISTER, ext_reg);
> +
> +    /* Enable Fout */
> +    irq_set(RX8900_TEST_ID, RX8900_FOUT_ENABLE, 0, true);
> +
> +    fout_count_reset();
> +    wait_cycles(2 * 1000000000ULL, 100000);
> +
> +    /* disable Fout */
> +    irq_set(RX8900_TEST_ID, RX8900_FOUT_ENABLE, 0, false);
> +
> +    g_assert_cmpuint(fout_counts, ==, 1024 * 2);
> +}
> +
> +/**
> + * Check that Fout operates at 32768Hz
> + */
> +static void check_fout_32768hz(void)
> +{
> +    uint8_t ext_reg = read_register(EXTENSION_REGISTER);
> +    ext_reg &= ~EXT_MASK_FSEL0;
> +    ext_reg &= ~EXT_MASK_FSEL1;
> +    write_register(EXTENSION_REGISTER, ext_reg);
> +
> +    /* Enable Fout */
> +    irq_set(RX8900_TEST_ID, RX8900_FOUT_ENABLE, 0, true);
> +
> +    fout_count_reset();
> +    wait_cycles(2 * 1000000000ULL, 15000);
> +
> +    /* disable Fout */
> +    irq_set(RX8900_TEST_ID, RX8900_FOUT_ENABLE, 0, false);
> +
> +    /* There appears to be some rounding errors in the timer,
> +     * we'll tolerate it for now
> +     */
> +    g_assert_cmpuint(fout_counts, >=, 32768 * 2);
> +    g_assert_cmpuint(fout_counts, <=, 65540);

Maybe it would be more intuitive to write this as (32768 * 2 + 4) so
it's clear what the tolerance is.

> +}
> +
> +/**
> + * Check the countdown timer operates at 1 Hz
> + */
> +static void check_countdown_1hz(void)
> +{
> +    uint8_t ext_reg;
> +
> +    write_register(TIMER_COUNTER_0, 5);
> +    write_register(TIMER_COUNTER_1, 0);
> +
> +    ext_reg = read_register(EXTENSION_REGISTER);
> +    ext_reg &= ~EXT_MASK_TSEL1;
> +    ext_reg |= EXT_MASK_TSEL0;
> +    ext_reg |= EXT_MASK_TE;
> +    write_register(EXTENSION_REGISTER, ext_reg);
> +    set_bits_in_register(CONTROL_REGISTER, CTRL_MASK_TIE);
> +
> +    count_reset();
> +    wait_cycles(5 * 1000000000ULL, 1000000);
> +
> +    g_assert_cmpuint(interrupt_counts[FLAG_REG_TF], ==, 0);
> +
> +    wait_cycles(1 * 1000000000ULL, 1000000);
> +
> +    g_assert_cmpuint(interrupt_counts[FLAG_REG_TF], ==, 1);
> +}
> +
> +/**
> + * Check the countdown timer operates at 64 Hz
> + */
> +static void check_countdown_64hz(void)
> +{
> +    uint8_t ext_reg;
> +
> +    write_register(TIMER_COUNTER_0, 0x40);
> +    write_register(TIMER_COUNTER_1, 0x01); /* 5 * 64 */
> +
> +    ext_reg = read_register(EXTENSION_REGISTER);
> +    ext_reg &= ~EXT_MASK_TSEL0;
> +    ext_reg &= ~EXT_MASK_TSEL1;
> +    ext_reg |= EXT_MASK_TE;
> +    write_register(EXTENSION_REGISTER, ext_reg);
> +    set_bits_in_register(CONTROL_REGISTER, CTRL_MASK_TIE);
> +
> +    count_reset();
> +    wait_cycles(5 * 1000000000ULL, 1000000);
> +
> +    g_assert_cmpuint(interrupt_counts[FLAG_REG_TF], ==, 0);
> +
> +    wait_cycles(1 * 1000000000ULL, 1000000);
> +
> +    g_assert_cmpuint(interrupt_counts[FLAG_REG_TF], ==, 1);
> +}
> +
> +/**
> + * Check the countdown timer operates at 4096 Hz
> + */
> +static void check_countdown_4096hz(void)
> +{
> +    uint8_t ext_reg;
> +
> +    write_register(TIMER_COUNTER_0, 0xFF);
> +    write_register(TIMER_COUNTER_1, 0x0F); /* 4095 */
> +    ext_reg = read_register(EXTENSION_REGISTER);
> +    ext_reg |= EXT_MASK_TSEL0;
> +    ext_reg |= EXT_MASK_TSEL1;
> +    ext_reg |= EXT_MASK_TE;
> +    write_register(EXTENSION_REGISTER, ext_reg);
> +    set_bits_in_register(CONTROL_REGISTER, CTRL_MASK_TIE);
> +
> +    count_reset();
> +    wait_cycles(999755859ULL, 10000);
> +
> +    g_assert_cmpuint(interrupt_counts[FLAG_REG_TF], ==, 0);
> +
> +    wait_cycles(244141ULL, 10000);
> +
> +    g_assert_cmpuint(interrupt_counts[FLAG_REG_TF], ==, 1);
> +}
> +
> +/**
> + * Check the countdown timer operates at 1 minute
> + */
> +static void check_countdown_1m(void)
> +{
> +    uint8_t ext_reg;
> +
> +    write_register(TIMER_COUNTER_0, 0x01);
> +    write_register(TIMER_COUNTER_1, 0x00);
> +    ext_reg = read_register(EXTENSION_REGISTER);
> +    ext_reg &= ~EXT_MASK_TSEL0;
> +    ext_reg |= EXT_MASK_TSEL1;
> +    ext_reg |= EXT_MASK_TE;
> +    write_register(EXTENSION_REGISTER, ext_reg);
> +    set_bits_in_register(CONTROL_REGISTER, CTRL_MASK_TIE);
> +
> +    count_reset();
> +    wait_cycles(59 * 1000000000ULL, 100000);
> +
> +    g_assert_cmpuint(interrupt_counts[FLAG_REG_TF], ==, 0);
> +
> +    wait_cycles(1000000001LL, 100000);
> +
> +    g_assert_cmpuint(interrupt_counts[FLAG_REG_TF], ==, 1);
> +}
> +
> +/**
> + * Check that the voltage can be altered via properties
> + */
> +static void check_voltage(void)
> +{
> +    uint8_t flags = read_register(FLAG_REGISTER) &
> +            (FLAG_MASK_VDET | FLAG_MASK_VLF);
> +
> +    /* start from a good state */
> +    g_assert_cmpuint(flags, == , 0x00);
> +
> +    /* 1.9V triggers VDET but not VLF */
> +    qmp_rx8900_set_voltage(RX8900_TEST_ID, 1.9f);
> +
> +    flags = read_register(FLAG_REGISTER) & (FLAG_MASK_VDET | FLAG_MASK_VLF);
> +    g_assert_cmpuint(flags, == , FLAG_MASK_VDET);
> +
> +    /* Clearing the flag should reassert it as the voltage is still low */
> +    write_register(FLAG_REGISTER, 0x00);
> +
> +    flags = read_register(FLAG_REGISTER) & (FLAG_MASK_VDET | FLAG_MASK_VLF);
> +    g_assert_cmpuint(flags, == , FLAG_MASK_VDET);
> +
> +    /* Set the voltage to a good level, the low voltage flag should persist */
> +    qmp_rx8900_set_voltage(RX8900_TEST_ID, 3.3f);
> +
> +    flags = read_register(FLAG_REGISTER) & (FLAG_MASK_VDET | FLAG_MASK_VLF);
> +    g_assert_cmpuint(flags, == , FLAG_MASK_VDET);
> +
> +    /* We should be able to clear the flag with a good voltage */
> +    write_register(FLAG_REGISTER, 0x00);
> +
> +    flags = read_register(FLAG_REGISTER) & (FLAG_MASK_VDET | FLAG_MASK_VLF);
> +    g_assert_cmpuint(flags, == , 0x00);
> +
> +
> +    /* 1.5V should trigger both VDET & VLF */
> +    qmp_rx8900_set_voltage(RX8900_TEST_ID, 1.5f);
> +    flags = read_register(FLAG_REGISTER) & (FLAG_MASK_VDET | FLAG_MASK_VLF);
> +    g_assert_cmpuint(flags, == , FLAG_MASK_VDET | FLAG_MASK_VLF);
> +
> +
> +    /* Clearing the flag should reassert it as the voltage is still low */
> +    write_register(FLAG_REGISTER, 0x00);
> +
> +    flags = read_register(FLAG_REGISTER) & (FLAG_MASK_VDET | FLAG_MASK_VLF);
> +    g_assert_cmpuint(flags, == , FLAG_MASK_VDET | FLAG_MASK_VLF);
> +
> +    /* Set the voltage to a good level, the low voltage flag should persist */
> +    qmp_rx8900_set_voltage(RX8900_TEST_ID, 3.3f);
> +
> +    flags = read_register(FLAG_REGISTER) & (FLAG_MASK_VDET | FLAG_MASK_VLF);
> +    g_assert_cmpuint(flags, == , FLAG_MASK_VDET | FLAG_MASK_VLF);
> +
> +    /* We should be able to clear the flag with a good voltage */
> +    write_register(FLAG_REGISTER, 0x00);
> +
> +    flags = read_register(FLAG_REGISTER) & (FLAG_MASK_VDET | FLAG_MASK_VLF);
> +    g_assert_cmpuint(flags, == , 0);
> +}
> +
> +
> +
> +int main(int argc, char **argv)
> +{
> +    QTestState *s = NULL;
> +    int ret;
> +    char args[255];
> +    snprintf(args, sizeof(args), "-display none -machine imx25-pdk "
> +            "-device rx8900,bus=i2c-bus.0,address=0x%x,id=%s"
> +#ifdef RX8900_TRACE
> +            " -trace events=/tmp/events"
> +#endif
> +            ,
> +            RX8900_ADDR, RX8900_TEST_ID);
> +
> +    g_test_init(&argc, &argv, NULL);
> +
> +    s = qtest_start(args);
> +    i2c = imx_i2c_create(IMX25_I2C_0_BASE);
> +    addr = RX8900_ADDR;
> +
> +    irq_intercept_out(RX8900_TEST_ID);
> +    irq_attach(RX8900_INTERRUPT_OUT, 0, handle_interrupt, NULL);
> +    irq_attach(RX8900_FOUT, 0, handle_fout, NULL);
> +
> +    qtest_add_func("/rx8900/reset", check_reset);
> +    qtest_add_func("/rx8900/tx-rx", send_and_receive);
> +    qtest_add_func("/rx8900/temperature", check_temperature);
> +    qtest_add_func("/rx8900/rollover", check_rollover);
> +    qtest_add_func("/rx8900/update-interrupt-disabled",
> +            check_update_interrupt_disabled);
> +    qtest_add_func("/rx8900/update-interrupt-seconds",
> +            check_update_interrupt_seconds);
> +    qtest_add_func("/rx8900/update-interrupt-minutes",
> +            check_update_interrupt_minutes);
> +    qtest_add_func("/rx8900/alarm-interrupt-disabled",
> +            check_alarm_interrupt_disabled);
> +    qtest_add_func("/rx8900/alarm-interrupt-month",
> +            check_alarm_interrupt_day_of_month);
> +    qtest_add_func("/rx8900/alarm-interrupt-month-negative",
> +            check_alarm_interrupt_day_of_month_negative);
> +    qtest_add_func("/rx8900/alarm-interrupt-week",
> +            check_alarm_interrupt_day_of_week);
> +    qtest_add_func("/rx8900/alarm-interrupt-week-negative",
> +            check_alarm_interrupt_day_of_week_negative);
> +    qtest_add_func("/rx8900/fout_1hz", check_fout_1hz);
> +    qtest_add_func("/rx8900/fout_1024hz", check_fout_1024hz);
> +    qtest_add_func("/rx8900/fout_32768hz", check_fout_32768hz);
> +    qtest_add_func("/rx8900/countdown_1hz", check_countdown_1hz);
> +    qtest_add_func("/rx8900/countdown_64hz", check_countdown_64hz);
> +    qtest_add_func("/rx8900/countdown_4096hz", check_countdown_4096hz);
> +    qtest_add_func("/rx8900/countdown_1m", check_countdown_1m);
> +    qtest_add_func("/rx8900/low_voltage", check_voltage);
> +
> +    ret = g_test_run();
> +
> +    if (s) {
> +        qtest_quit(s);
> +    }
> +    g_free(i2c);
> +
> +    return ret;
> +}

Andrew