Re: [PATCH v2 11/12] aspeed: Introduce a "bmc-console" machine option

[Joel Stanley]

On Wed, 7 Jun 2023 at 04:40, Cédric Le Goater <clg@kaod.org> wrote:
>
> Most of the Aspeed machines use the UART5 device for the boot console,
> and QEMU connects the first serial Chardev to this SoC device for this
> purpose. See routine connect_serial_hds_to_uarts().
>
> Nevertheless, some machines use another boot console, such as the fuji,
> and commit 5d63d0c76c ("hw/arm/aspeed: Allow machine to set UART
> default") introduced a SoC class attribute 'uart_default' and property
> to be able to change the boot console device. It was later changed by
> commit d2b3eaefb4 ("aspeed: Refactor UART init for multi-SoC machines").
>
> The "bmc-console" machine option goes a step further and lets the user define
> the UART device from the QEMU command line without introducing a new
> machine definition. For instance, to use device UART3 (mapped on
> /dev/ttyS2 under Linux) instead of the default UART5, one would use :
>
>   -M ast2500-evb,bmc-console=uart3
>
> Cc: Abhishek Singh Dagur <abhishek@drut.io>
> Signed-off-by: Cédric Le Goater <clg@kaod.org>

Reviewed-by: Joel Stanley <joel@jms.id.au>

> ---
>  docs/system/arm/aspeed.rst | 11 +++++++++++
>  hw/arm/aspeed.c            | 40 ++++++++++++++++++++++++++++++++++++--
>  2 files changed, 49 insertions(+), 2 deletions(-)
>
> diff --git a/docs/system/arm/aspeed.rst b/docs/system/arm/aspeed.rst
> index d4e293e7f986..80538422a1a4 100644
> --- a/docs/system/arm/aspeed.rst
> +++ b/docs/system/arm/aspeed.rst
> @@ -122,6 +122,11 @@ Options specific to Aspeed machines are :
>
>   * ``spi-model`` to change the SPI Flash model.
>
> + * ``bmc-console`` to change the default console device. Most of the
> +   machines use the ``UART5`` device for a boot console, which is
> +   mapped on ``/dev/ttyS4`` under Linux, but it is not always the
> +   case.
> +
>  For instance, to start the ``ast2500-evb`` machine with a different
>  FMC chip and a bigger (64M) SPI chip, use :
>
> @@ -129,6 +134,12 @@ FMC chip and a bigger (64M) SPI chip, use :
>
>    -M ast2500-evb,fmc-model=mx25l25635e,spi-model=mx66u51235f
>
> +To change the boot console and use device ``UART3`` (``/dev/ttyS2``
> +under Linux), use :
> +
> +.. code-block:: bash
> +
> +  -M ast2500-evb,bmc-console=uart3
>
>  Aspeed minibmc family boards (``ast1030-evb``)
>  ==================================================================
> diff --git a/hw/arm/aspeed.c b/hw/arm/aspeed.c
> index 8beed0c2a66e..d3e58936e68a 100644
> --- a/hw/arm/aspeed.c
> +++ b/hw/arm/aspeed.c
> @@ -43,6 +43,7 @@ struct AspeedMachineState {
>      AspeedSoCState soc;
>      MemoryRegion boot_rom;
>      bool mmio_exec;
> +    uint32_t uart_chosen;
>      char *fmc_model;
>      char *spi_model;
>  };
> @@ -331,10 +332,11 @@ static void 
> connect_serial_hds_to_uarts(AspeedMachineState *bmc)
>      AspeedMachineClass *amc = ASPEED_MACHINE_GET_CLASS(bmc);
>      AspeedSoCState *s = &bmc->soc;
>      AspeedSoCClass *sc = ASPEED_SOC_GET_CLASS(s);
> +    int uart_chosen = bmc->uart_chosen ? bmc->uart_chosen : 
> amc->uart_default;
>
> -    aspeed_soc_uart_set_chr(s, amc->uart_default, serial_hd(0));
> +    aspeed_soc_uart_set_chr(s, uart_chosen, serial_hd(0));
>      for (int i = 1, uart = ASPEED_DEV_UART1; i < sc->uarts_num; i++, uart++) 
> {
> -        if (uart == amc->uart_default) {
> +        if (uart == uart_chosen) {
>              continue;
>          }
>          aspeed_soc_uart_set_chr(s, uart, serial_hd(i));
> @@ -1079,6 +1081,35 @@ static void aspeed_set_spi_model(Object *obj, const 
> char *value, Error **errp)
>      bmc->spi_model = g_strdup(value);
>  }
>
> +static char *aspeed_get_bmc_console(Object *obj, Error **errp)
> +{
> +    AspeedMachineState *bmc = ASPEED_MACHINE(obj);
> +    AspeedMachineClass *amc = ASPEED_MACHINE_GET_CLASS(bmc);
> +    int uart_chosen = bmc->uart_chosen ? bmc->uart_chosen : 
> amc->uart_default;
> +
> +    return g_strdup_printf("uart%d", uart_chosen - ASPEED_DEV_UART1 + 1);
> +}
> +
> +static void aspeed_set_bmc_console(Object *obj, const char *value, Error 
> **errp)
> +{
> +    AspeedMachineState *bmc = ASPEED_MACHINE(obj);
> +    AspeedMachineClass *amc = ASPEED_MACHINE_GET_CLASS(bmc);
> +    AspeedSoCClass *sc = 
> ASPEED_SOC_CLASS(object_class_by_name(amc->soc_name));
> +    int val;
> +
> +    if (sscanf(value, "uart%u", &val) != 1) {
> +        error_setg(errp, "Bad value for \"uart\" property");
> +        return;
> +    }
> +
> +    /* The number of UART depends on the SoC */
> +    if (val < 1 || val > sc->uarts_num) {
> +        error_setg(errp, "\"uart\" should be in range [1 - %d]", 
> sc->uarts_num);
> +        return;
> +    }
> +    bmc->uart_chosen = ASPEED_DEV_UART1 + val - 1;
> +}
> +
>  static void aspeed_machine_class_props_init(ObjectClass *oc)
>  {
>      object_class_property_add_bool(oc, "execute-in-place",
> @@ -1087,6 +1118,11 @@ static void 
> aspeed_machine_class_props_init(ObjectClass *oc)
>      object_class_property_set_description(oc, "execute-in-place",
>                             "boot directly from CE0 flash device");
>
> +    object_class_property_add_str(oc, "bmc-console", aspeed_get_bmc_console,
> +                                  aspeed_set_bmc_console);
> +    object_class_property_set_description(oc, "bmc-console",
> +                           "Change the default UART to \"uartX\"");
> +
>      object_class_property_add_str(oc, "fmc-model", aspeed_get_fmc_model,
>                                     aspeed_set_fmc_model);
>      object_class_property_set_description(oc, "fmc-model",
> --
> 2.40.1
>