Re: [PATCH v1 4/6] riscv/sifive_u: Add the start-in-flash property

[Bin Meng]

On Fri, Sep 20, 2019 at 6:32 AM Alistair Francis
<address@hidden> wrote:
>
> Add a property that when set to true QEMU will jump from the ROM code to
> the start of flash memory instead of DRAM which is the default
> behaviour.
>
> Signed-off-by: Alistair Francis <address@hidden>
> ---
>  hw/riscv/sifive_u.c         | 27 +++++++++++++++++++++++++++
>  include/hw/riscv/sifive_u.h |  2 ++
>  2 files changed, 29 insertions(+)
>
> diff --git a/hw/riscv/sifive_u.c b/hw/riscv/sifive_u.c
> index c3949fb316..b7cd3631cd 100644
> --- a/hw/riscv/sifive_u.c
> +++ b/hw/riscv/sifive_u.c
> @@ -373,6 +373,10 @@ static void riscv_sifive_u_init(MachineState *machine)
>                                         /* dtb: */
>      };
>
> +    if (s->start_in_flash) {
> +        reset_vec[6] = memmap[SIFIVE_U_FLASH0].base; /* start: .dword 
> FLASH0_BASE */
> +    }
> +
>      /* copy in the reset vector in little_endian byte order */
>      for (i = 0; i < sizeof(reset_vec) >> 2; i++) {
>          reset_vec[i] = cpu_to_le32(reset_vec[i]);
> @@ -544,8 +548,31 @@ static void riscv_sifive_u_soc_realize(DeviceState *dev, 
> Error **errp)
>          memmap[SIFIVE_U_GEM_MGMT].base, memmap[SIFIVE_U_GEM_MGMT].size);
>  }
>
> +static bool virt_get_start_in_flash(Object *obj, Error **errp)
> +{
> +    SiFiveUState *s = RISCV_U_MACHINE(obj);
> +
> +    return s->start_in_flash;
> +}
> +
> +static void virt_set_start_in_flash(Object *obj, bool value, Error **errp)
> +{
> +    SiFiveUState *s = RISCV_U_MACHINE(obj);
> +
> +    s->start_in_flash = value;
> +}
> +
>  static void riscv_sifive_u_machine_instance_init(Object *obj)
>  {
> +    SiFiveUState *s = RISCV_U_MACHINE(obj);
> +
> +    s->start_in_flash = false;
> +    object_property_add_bool(obj, "start-in-flash", virt_get_start_in_flash,
> +                             virt_set_start_in_flash, NULL);
> +    object_property_set_description(obj, "start-in-flash",
> +                                    "Set on to tell QEMU's ROM to jump to " \
> +                                    "flash. Otherwise QEMU will jump to 
> DRAM",
> +                                    NULL);
>
>  }
>
> diff --git a/include/hw/riscv/sifive_u.h b/include/hw/riscv/sifive_u.h
> index a921079fbe..2656b43c58 100644
> --- a/include/hw/riscv/sifive_u.h
> +++ b/include/hw/riscv/sifive_u.h
> @@ -57,6 +57,8 @@ typedef struct SiFiveUState {
>
>      void *fdt;
>      int fdt_size;
> +
> +    bool start_in_flash;
>  } SiFiveUState;
>
>  enum {

This patch chose a different way from the one used in patch "[v1,6/6]
riscv/virt: Jump to pflash if specified":

- this patch uses reset_vec[6] while patch [6/6] defines a variable start_addr
- this patch adds a "start-in-flash" property to the machine, while
patch [6/6] tests against drive IF_PFLASH

We should be consistent and I would prefer to use the patch [6/6] way.
On Unleashed an SPI flash is mounted so we cannot add a PFlash to
sifive_u machine like what was done on virt machine, so we should test
IF_MTD instead. Thoughts?

Regards,
Bin