Re: [PATCH v4 4/4] hw/block/m25p80: Fix Numonyx fast read dummy cycle count

[Francisco Iglesias]

Hi Joe,

On Thu, Nov 12, 2020 at 07:10:55PM -0800, Joe Komlodi wrote:
> Numonyx chips determine the number of cycles to wait based on bits 7:4
> in the volatile configuration register.
> 
> However, if these bits are 0x0 or 0xF, the number of dummy cycles to
> wait is
> 10 on a QIOR or QIOR4 command, or 8 on any other currently supported
> fast read command. [1]

With above changed to:

"
However, if these bits are 0x0 or 0xF, the number of dummy cycles to wait
is 10 on a QIOR or QIOR4 command or when in QIO mode and else 8 for the
currently supported fast read commands. [1]
"

Reviewed-by: Francisco Iglesias <francisco.iglesias@xilinx.com>

Best regards,
Francisco Iglesias


> 
> [1]
> https://www.micron.com/-/media/client/global/documents/products/data-sheet/nor-flash/serial-nor/mt25q/die-rev-b/mt25q_qlkt_u_02g_cbb_0.pdf?rev=9b167fbf2b3645efba6385949a72e453
> 
> Signed-off-by: Joe Komlodi <komlodi@xilinx.com>
> ---
>  hw/block/m25p80.c | 30 +++++++++++++++++++++++++++---
>  1 file changed, 27 insertions(+), 3 deletions(-)
> 
> diff --git a/hw/block/m25p80.c b/hw/block/m25p80.c
> index 2552f2c..0c78015 100644
> --- a/hw/block/m25p80.c
> +++ b/hw/block/m25p80.c
> @@ -837,6 +837,30 @@ static uint8_t numonyx_get_mode(Flash *s)
>      }
>  }
>  
> +static uint8_t numonyx_extract_cfg_num_dummies(Flash *s)
> +{
> +    uint8_t num_dummies;
> +    uint8_t mode;
> +    assert(get_man(s) == MAN_NUMONYX);
> +
> +    mode = numonyx_get_mode(s);
> +    num_dummies = extract32(s->volatile_cfg, 4, 4);
> +
> +    if (num_dummies == 0x0 || num_dummies == 0xf) {
> +        switch (s->cmd_in_progress) {
> +        case QIOR:
> +        case QIOR4:
> +            num_dummies = 10;
> +            break;
> +        default:
> +            num_dummies = (mode == MODE_QIO) ? 10 : 8;
> +            break;
> +        }
> +    }
> +
> +    return num_dummies;
> +}
> +
>  static void decode_fast_read_cmd(Flash *s)
>  {
>      s->needed_bytes = get_addr_length(s);
> @@ -847,7 +871,7 @@ static void decode_fast_read_cmd(Flash *s)
>          s->state = STATE_COLLECTING_DATA;
>          break;
>      case MAN_NUMONYX:
> -        s->needed_bytes += extract32(s->volatile_cfg, 4, 4);
> +        s->needed_bytes += numonyx_extract_cfg_num_dummies(s);
>          s->state = STATE_COLLECTING_DATA;
>          break;
>      case MAN_MACRONIX:
> @@ -891,7 +915,7 @@ static void decode_dio_read_cmd(Flash *s)
>          s->state = STATE_COLLECTING_DATA;
>          break;
>      case MAN_NUMONYX:
> -        s->needed_bytes += extract32(s->volatile_cfg, 4, 4);
> +        s->needed_bytes += numonyx_extract_cfg_num_dummies(s);
>          s->state = STATE_COLLECTING_DATA;
>          break;
>      case MAN_MACRONIX:
> @@ -935,7 +959,7 @@ static void decode_qio_read_cmd(Flash *s)
>          s->state = STATE_COLLECTING_DATA;
>          break;
>      case MAN_NUMONYX:
> -        s->needed_bytes += extract32(s->volatile_cfg, 4, 4);
> +        s->needed_bytes += numonyx_extract_cfg_num_dummies(s);
>          s->state = STATE_COLLECTING_DATA;
>          break;
>      case MAN_MACRONIX:
> -- 
> 2.7.4
>