Re: [PATCH v2 3/4] riscv: qemu: Implement is_flash_available() for MTD NOR

Heinrich Schuchardt
2022-02-06T10:01:01Z

On 1/27/22 07:11, Anup Patel wrote:
> Currently, if MTD NOR is enabled then U-Boot tries to issue flash
> commands even when CFI flash DT node is not present. This causes
> access fault on RISC-V emulators or ISS which do not emulate CFI
> flash. To handle this issue, we implement is_flash_available() for
> qemu-riscv board which will return 1 only if CFI flash DT node is
> present.
>
> Fixes: d248627f9d42 ("riscv: qemu: Enable MTD NOR flash support")
> Signed-off-by: Anup Patel <apatel@ventanamicro.com>
> Reviewed-by: Rick Chen <rick@andestech.com>
> ---
> board/emulation/qemu-riscv/qemu-riscv.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/board/emulation/qemu-riscv/qemu-riscv.c b/board/emulation/qemu-riscv/qemu-riscv.c
> index b0d9dd59b1..ae3b7a3295 100644
> --- a/board/emulation/qemu-riscv/qemu-riscv.c
> +++ b/board/emulation/qemu-riscv/qemu-riscv.c
> @@ -5,6 +5,7 @@
>
> #include <common.h>
> #include <dm.h>
> +#include <dm/ofnode.h>
> #include <env.h>
> #include <fdtdec.h>
> #include <image.h>
> @@ -16,6 +17,17 @@
>
> DECLARE_GLOBAL_DATA_PTR;
>
> +#if IS_ENABLED(CONFIG_MTD_NOR_FLASH)

I do not think that we need an #if here. The weak function is only
defined and called if CONFIG_MTD_NOR_FLASH=y (cf. common/board_r.c).
Without the #if the linker will detect that this function is not needed
and will eliminate it if CONFIG_MTD_NOR_FLASH=n.

As this ensures that the function is always compiled this is the
preferred way of implementation.

> +int is_flash_available(void)

Currently there is no include defining the is_flash_available(). This
needs to be fixed.

Best regards

Heinrich

> +{
> + if (!ofnode_equal(ofnode_by_compatible(ofnode_null(), "cfi-flash"),
> + ofnode_null()))
> + return 1;
> +
> + return 0;
> +}
> +#endif
> +
> int board_init(void)
> {
> /*