Re: [PATCH for-5.1] hw/arm/netduino2, netduinoplus2: Set system_clock_scale

[Alistair Francis]

On Mon, Jul 27, 2020 at 9:26 AM Peter Maydell <peter.maydell@linaro.org> wrote:
>
> The netduino2 and netduinoplus2 boards forgot to set the system_clock_scale
> global, which meant that if guest code used the systick timer in "use
> the processor clock" mode it would hang because time never advances.
>
> Set the global to match the documented CPU clock speed of these boards.
> Judging by the data sheet this is slightly simplistic because the
> SoC allows configuration of the SYSCLK source and frequency via the
> RCC (reset and clock control) module, but we don't model that.
>
> Fixes: https://bugs.launchpad.net/qemu/+bug/1876187
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

Alistair

> ---
> NB: tested with "make check" only...
>
>  hw/arm/netduino2.c     | 10 ++++++++++
>  hw/arm/netduinoplus2.c | 10 ++++++++++
>  2 files changed, 20 insertions(+)
>
> diff --git a/hw/arm/netduino2.c b/hw/arm/netduino2.c
> index 79e19392b56..8f103341443 100644
> --- a/hw/arm/netduino2.c
> +++ b/hw/arm/netduino2.c
> @@ -30,10 +30,20 @@
>  #include "hw/arm/stm32f205_soc.h"
>  #include "hw/arm/boot.h"
>
> +/* Main SYSCLK frequency in Hz (120MHz) */
> +#define SYSCLK_FRQ 120000000ULL
> +
>  static void netduino2_init(MachineState *machine)
>  {
>      DeviceState *dev;
>
> +    /*
> +     * TODO: ideally we would model the SoC RCC and let it handle
> +     * system_clock_scale, including its ability to define different
> +     * possible SYSCLK sources.
> +     */
> +    system_clock_scale = NANOSECONDS_PER_SECOND / SYSCLK_FRQ;
> +
>      dev = qdev_new(TYPE_STM32F205_SOC);
>      qdev_prop_set_string(dev, "cpu-type", ARM_CPU_TYPE_NAME("cortex-m3"));
>      sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &error_fatal);
> diff --git a/hw/arm/netduinoplus2.c b/hw/arm/netduinoplus2.c
> index 958d21dd9f9..68abd3ec69d 100644
> --- a/hw/arm/netduinoplus2.c
> +++ b/hw/arm/netduinoplus2.c
> @@ -30,10 +30,20 @@
>  #include "hw/arm/stm32f405_soc.h"
>  #include "hw/arm/boot.h"
>
> +/* Main SYSCLK frequency in Hz (168MHz) */
> +#define SYSCLK_FRQ 168000000ULL
> +
>  static void netduinoplus2_init(MachineState *machine)
>  {
>      DeviceState *dev;
>
> +    /*
> +     * TODO: ideally we would model the SoC RCC and let it handle
> +     * system_clock_scale, including its ability to define different
> +     * possible SYSCLK sources.
> +     */
> +    system_clock_scale = NANOSECONDS_PER_SECOND / SYSCLK_FRQ;
> +
>      dev = qdev_new(TYPE_STM32F405_SOC);
>      qdev_prop_set_string(dev, "cpu-type", ARM_CPU_TYPE_NAME("cortex-m4"));
>      sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &error_fatal);
> --
> 2.20.1
>
>