Re: [Qemu-devel] [PATCH 2/2] hw/pflash_cfi01: Treat read in unknown command state as read

[Peter Crosthwaite]

On Tue, Jan 22, 2013 at 12:08 AM, Peter Maydell
<address@hidden> wrote:
> The code for handling the default "unknown command state" case in
> pflash_read in pflash_cfi01.c comments "reset state & treat it as
> a read". However the code doesn't actually do this. Moving the
> default case to the top of the switch so it can fall through into
> the read case brings this file into line with pflash_cfi02 and
> makes the code behave as the comments suggest.
>
> The pflash_cfi01 code has always had this bug -- it was presumably
> introduced when the original author copied the cfi02 code and
> rearranged the order of the switch statement without noticing
> that the default case relied on the fall-through.
>
> Signed-off-by: Peter Maydell <address@hidden>

Reviewed-by: Peter Crosthwaite <address@hidden>
Tested-by: Peter Crosthwaite <address@hidden>

> ---
>  hw/pflash_cfi01.c |   11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/hw/pflash_cfi01.c b/hw/pflash_cfi01.c
> index 310c716..b30cac6 100644
> --- a/hw/pflash_cfi01.c
> +++ b/hw/pflash_cfi01.c
> @@ -122,6 +122,12 @@ static uint32_t pflash_read (pflash_t *pfl, hwaddr 
> offset,
>              __func__, offset, pfl->cmd, width);
>  #endif
>      switch (pfl->cmd) {
> +    default:
> +        /* This should never happen : reset state & treat it as a read */
> +        DPRINTF("%s: unknown command state: %x\n", __func__, pfl->cmd);
> +        pfl->wcycle = 0;
> +        pfl->cmd = 0;
> +        /* fall through to read code */
>      case 0x00:
>          /* Flash area read */
>          p = pfl->storage;
> @@ -197,11 +203,6 @@ static uint32_t pflash_read (pflash_t *pfl, hwaddr 
> offset,
>          else
>              ret = pfl->cfi_table[boff];
>          break;
> -    default:
> -        /* This should never happen : reset state & treat it as a read */
> -        DPRINTF("%s: unknown command state: %x\n", __func__, pfl->cmd);
> -        pfl->wcycle = 0;
> -        pfl->cmd = 0;
>      }
>      return ret;
>  }
> --
> 1.7.9.5
>
>