Re: [PATCH 2/2] hw/arm: Add Olimex H405

[Philippe Mathieu-Daudé]

On 18/12/22 08:12, Felipe Balbi wrote:
> Olimex makes a series of low-cost STM32 boards. This commit introduces
> the minimum setup to support SMT32-H405. See [1] for details
>
> [1] https://www.olimex.com/Products/ARM/ST/STM32-H405/
>
> Signed-off-by: Felipe Balbi <balbi@kernel.org>
> ---
>   MAINTAINERS                             |  6 +++
>   configs/devices/arm-softmmu/default.mak |  1 +
>   hw/arm/Kconfig                          |  4 ++
>   hw/arm/meson.build                      |  1 +
>   hw/arm/olimex-stm32-h405.c              | 65 +++++++++++++++++++++++++
>   5 files changed, 77 insertions(+)
>   create mode 100644 hw/arm/olimex-stm32-h405.c

See also docs/system/arm/stm32.rst

> diff --git a/hw/arm/meson.build b/hw/arm/meson.build
> index 92f9f6e000ea..76d4d650e42e 100644
> --- a/hw/arm/meson.build
> +++ b/hw/arm/meson.build
> @@ -12,6 +12,7 @@ arm_ss.add(when: 'CONFIG_MICROBIT', if_true: 
> files('microbit.c'))
>   arm_ss.add(when: 'CONFIG_MUSICPAL', if_true: files('musicpal.c'))
>   arm_ss.add(when: 'CONFIG_NETDUINO2', if_true: files('netduino2.c'))
>   arm_ss.add(when: 'CONFIG_NETDUINOPLUS2', if_true: files('netduinoplus2.c'))
> +arm_ss.add(when: 'CONFIG_OLIMEX_STM32_H405', if_true: 
> files('olimex-stm32-h405.c'))
>   arm_ss.add(when: 'CONFIG_NPCM7XX', if_true: files('npcm7xx.c', 
> 'npcm7xx_boards.c'))
>   arm_ss.add(when: 'CONFIG_NSERIES', if_true: files('nseries.c'))
>   arm_ss.add(when: 'CONFIG_SX1', if_true: files('omap_sx1.c'))
> diff --git a/hw/arm/olimex-stm32-h405.c b/hw/arm/olimex-stm32-h405.c
> new file mode 100644
> index 000000000000..5171a66074bb
> --- /dev/null
> +++ b/hw/arm/olimex-stm32-h405.c
> @@ -0,0 +1,65 @@
> +/*
> + * ST STM32VLDISCOVERY machine
> + * Olimex STM32-H405 machine
> + *
> + * Copyright (c) 2022 Felipe Balbi <balbi@kernel.org>
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a copy
> + * of this software and associated documentation files (the "Software"), to 
> deal
> + * in the Software without restriction, including without limitation the rights
> + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
> + * copies of the Software, and to permit persons to whom the Software is
> + * furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
> FROM,
> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
> + * THE SOFTWARE.
> + */
> +
> +#include "qemu/osdep.h"
> +#include "qapi/error.h"
> +#include "hw/boards.h"
> +#include "hw/qdev-properties.h"
> +#include "hw/qdev-clock.h"
> +#include "qemu/error-report.h"
> +#include "hw/arm/stm32f405_soc.h"
> +#include "hw/arm/boot.h"
> +
> +/* olimex-stm32-h405 implementation is derived from netduinoplus2 */
> +
> +/* Main SYSCLK frequency in Hz (168MHz) */
> +#define SYSCLK_FRQ 168000000ULL

No need to comment if named MAIN_SYSCLK_FREQ_HZ.

> +static void olimex_stm32_h405_init(MachineState *machine)
> +{
> +    DeviceState *dev;
> +    Clock *sysclk;

I like the simplicity, but wonder if we shouldn't add checks such
the MPS2 machines, in case one use different -cpu / -m values:

       if (strcmp(machine->cpu_type, mc->default_cpu_type) != 0) {
           error_report("This board can only be used with CPU %s",
                        mc->default_cpu_type);
           exit(1);
       }

       if (machine->ram_size != mc->default_ram_size) {
           g_autofree char *sz = size_to_str(mc->default_ram_size);
           error_report("Invalid RAM size, should be %s", sz);
           exit(1);
       }

Or maybe better would be to refactor that since this pattern is common
to SoC/SoM.

> +    /* This clock doesn't need migration because it is fixed-frequency */
> +    sysclk = clock_new(OBJECT(machine), "SYSCLK");
> +    clock_set_hz(sysclk, SYSCLK_FRQ);
> +
> +    dev = qdev_new(TYPE_STM32F405_SOC);
> +    qdev_prop_set_string(dev, "cpu-type", ARM_CPU_TYPE_NAME("cortex-m4"));
> +    qdev_connect_clock_in(dev, "sysclk", sysclk);
> +    sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &error_fatal);
> +
> +    armv7m_load_kernel(ARM_CPU(first_cpu),
> +                       machine->kernel_filename,
> +                       0, FLASH_SIZE);
> +}
> +
> +static void olimex_stm32_h405_machine_init(MachineClass *mc)
> +{
> +    mc->desc = "Olimex STM32-H405 (Cortex-M4)";
> +    mc->init = olimex_stm32_h405_init;

Per previous comment:

       mc->default_cpu_type = ARM_CPU_TYPE_NAME("cortex-m4");
       mc->default_ram_size = 0; /* SRAM already allocated in SoC */

> +}
> +
> +DEFINE_MACHINE("olimex-stm32-h405", olimex_stm32_h405_machine_init)