Re: [Qemu-devel] [PATCH] m25p80: Fix QIOR/DIOR handling for Winbond

["Cédric Le Goater" <clg@kaod.org>]

Hello Marcin,

On 07/06/2016 02:43 PM, marcin.krzeminski@nokia.com wrote:
> From: Marcin Krzeminski <marcin.krzeminski@nokia.com>
> 
> Winbond also support continuous read mode, but as an opposite for other
> flash type read mode clock cycles are included to dummy cycles number.
> This path add proper handling of read mode byte and update needed
> dummy cycles. QPI mode and dummy cycles configuration are not supported.
> 
> Signed-off-by: Marcin Krzeminski <marcin.krzeminski@nokia.com>
> ---
>  hw/block/m25p80.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/block/m25p80.c b/hw/block/m25p80.c
> index d9b2793..a349544 100644
> --- a/hw/block/m25p80.c
> +++ b/hw/block/m25p80.c
> @@ -149,6 +149,7 @@ typedef struct FlashPartInfo {
>  */
>  
>  #define SPANSION_CONTINUOUS_READ_MODE_CMD_LEN 1
> +#define WINBOND_CONTINUOUS_READ_MODE_CMD_LEN 1

I checked the W25Q256FV datasheet and

>  static const FlashPartInfo known_devices[] = {
>      /* Atmel -- some are (confusingly) marketed as "DataFlash" */
> @@ -775,7 +776,7 @@ static void decode_dio_read_cmd(Flash *s)
>      /* Dummy cycles modeled with bytes writes instead of bits */
>      switch (get_man(s)) {
>      case MAN_WINBOND:
> -        s->needed_bytes += 8;
> +        s->needed_bytes += WINBOND_CONTINUOUS_READ_MODE_CMD_LEN;

this looks fine,

>          break;
>      case MAN_SPANSION:
>          s->needed_bytes += SPANSION_CONTINUOUS_READ_MODE_CMD_LEN;
> @@ -814,7 +815,8 @@ static void decode_qio_read_cmd(Flash *s)
>      /* Dummy cycles modeled with bytes writes instead of bits */
>      switch (get_man(s)) {
>      case MAN_WINBOND:
> -        s->needed_bytes += 8;
> +        s->needed_bytes += WINBOND_CONTINUOUS_READ_MODE_CMD_LEN;
> +        s->needed_bytes += 4;

but I don't understand the above. I see the address + M7-0 + 2 dummies.

Thanks,

C. 

>          break;
>      case MAN_SPANSION:
>          s->needed_bytes += SPANSION_CONTINUOUS_READ_MODE_CMD_LEN;
>