Re: [Qemu-devel] [PATCH arm-devs v1 1/5] sd/sd.c: Fix "inquiry" ACMD41

[Peter Crosthwaite <peter.crosthwaite@xilinx.com>]

Hi Igor,

On Wed, May 22, 2013 at 11:37 PM, Igor Mitsyanko <i.mitsyanko@gmail.com> wrote:
>
> On 05/21/2013 10:50 AM, peter.crosthwaite@xilinx.com wrote:
>
> From: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
>
> the SD command ACMD41 can be used in a read only mode to query device
> state without doing the SD card initialisation. This is valid even
> which the device is already initialised. Fix the command to be
> responsive when in the ready state accordingly.
>
> Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
> ---
>
>  hw/sd/sd.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/hw/sd/sd.c b/hw/sd/sd.c
> index 2e0ef3e..89bfb7a 100644
> --- a/hw/sd/sd.c
> +++ b/hw/sd/sd.c
> @@ -1277,6 +1277,7 @@ static sd_rsp_type_t sd_app_command(SDState *sd,
>          }
>          switch (sd->state) {
>          case sd_idle_state:
> +        case sd_ready_state:
>              /* We accept any voltage.  10000 V is nothing.  */
>              if (req.arg)
>                  sd->state = sd_ready_state;
>
>
> I couldn't find any info in SD specification that would confirm this change
> correctness, what about
> table "Table 4-29: Card State Transition Table" which states that ACMD41 is
> illegal in "ready" state?
>

By the letter of the spec I think you are right. Although this patch
is needed to make my QEMU consistent with my real hardware. I'll dig
deeper.

Regards,
Peter

> --
> Best wishes,
> Igor Mitsyanko
> email: i.mitsyanko@gmail.com