Re: [PATCH] hw/net: cadence_gem: feat: add logic for the DISABLE_MASK bit in type2_compare_x_word_1

[Philippe Mathieu-Daudé]

Hi Andrew,

On 18/11/24 12:48, Andrew.Yuan wrote:
> From: Andrew Yuan <andrew.yuan@jaguarmicro.com>
>
> As in the Cadence IP for Gigabit Ethernet MAC Part Number: IP7014 IP Rev: R1p12 
> - Doc Rev: 1.3 User Guide,
> if the DISABLE_MASK bit in type2_compare_x_word_1 is set,
> mask_value in type2_compare_x_word_0 is used as an additional 2 byte Compare 
> Value
>
> Signed-off-by: Andrew Yuan <andrew.yuan@jaguarmicro.com>
> ---
>   hw/net/cadence_gem.c | 25 ++++++++++++++++++++-----
>   1 file changed, 20 insertions(+), 5 deletions(-)
>
> diff --git a/hw/net/cadence_gem.c b/hw/net/cadence_gem.c
> index 526739887c..7ec5dbaa9c 100644
> --- a/hw/net/cadence_gem.c
> +++ b/hw/net/cadence_gem.c
> @@ -909,8 +909,8 @@ static int get_queue_from_screen(CadenceGEMState *s, 
> uint8_t *rxbuf_ptr,
>   
>           /* Compare A, B, C */
>           for (j = 0; j < 3; j++) {
> -            uint32_t cr0, cr1, mask, compare;
> -            uint16_t rx_cmp;
> +            uint32_t cr0, cr1, mask, compare, disable_mask;
> +            uint32_t rx_cmp;
>               int offset;
>               int cr_idx = extract32(reg, 
> R_SCREENING_TYPE2_REG0_COMPARE_A_SHIFT + j * 6,
>                                      R_SCREENING_TYPE2_REG0_COMPARE_A_LENGTH);
> @@ -946,9 +946,24 @@ static int get_queue_from_screen(CadenceGEMState *s, 
> uint8_t *rxbuf_ptr,
>                   break;
>               }
>   
> -            rx_cmp = rxbuf_ptr[offset] << 8 | rxbuf_ptr[offset];
> -            mask = FIELD_EX32(cr0, TYPE2_COMPARE_0_WORD_0, MASK_VALUE);
> -            compare = FIELD_EX32(cr0, TYPE2_COMPARE_0_WORD_0, COMPARE_VALUE);
> +            disable_mask =
> +                FIELD_EX32(cr1, TYPE2_COMPARE_0_WORD_1, DISABLE_MASK);
> +            if (disable_mask) {
> +                /*
> +                 * If disable_mask is set,
> +                 * mask_value is used as an additional 2 byte Compare Value.
> +                 * To simple, set mask = 0xFFFFFFFF, if disable_maks is set.

Typo "disable_mask".

> +                 */
> +                rx_cmp = rxbuf_ptr[offset + 3] << 8 | rxbuf_ptr[offset + 2] |\
> +                         rxbuf_ptr[offset + 1] << 8 | rxbuf_ptr[offset];

                   rx_cmp = ldl_be_p(rxbuf_ptr[offset]);

> +                mask = 0xFFFFFFFF;
> +                compare = cr0;
> +            } else {
> +                rx_cmp = rxbuf_ptr[offset + 1] << 8 | rxbuf_ptr[offset];

                   rx_cmp = lduw_be_p(rxbuf_ptr[offset]);

> +                mask = FIELD_EX32(cr0, TYPE2_COMPARE_0_WORD_0, MASK_VALUE);
> +                compare =
> +                    FIELD_EX32(cr0, TYPE2_COMPARE_0_WORD_0, COMPARE_VALUE);
> +            }
>   
>               if ((rx_cmp & mask) == (compare & mask)) {
>                   matched = true;