On Mon, Feb 7, 2022 at 1:00 PM Nithin Dabilpuram
<ndabilpu...@marvell.com> wrote:
>
> From: Satha Rao <skotesh...@marvell.com>
>
> New api to get floor values for a requested shaper rate, which can assure
Since it is internal API, no need to mention in the comment log
> packets should never be transmitted at a rate higher than configured.
>
> Keep the old api to get HW suggested values.
> And introduce new parameter to select appropriate api.
api -> API
>
> Signed-off-by: Satha Rao <skotesh...@marvell.com>
> ---
> +static uint64_t
> +nix_tm_shaper_rate_conv_floor(uint64_t value, uint64_t *exponent_p,
> + uint64_t *mantissa_p, uint64_t *div_exp_p)
> +{
> + uint64_t div_exp, exponent, mantissa;
> +
> + /* Boundary checks */
> + if (value < NIX_TM_MIN_SHAPER_RATE || value > NIX_TM_MAX_SHAPER_RATE)
> + return 0;
> +
> + if (value <= NIX_TM_SHAPER_RATE(0, 0, 0)) {
> + /* Calculate rate div_exp and mantissa using
> + * the following formula:
> + *
> + * value = (2E6 * (256 + mantissa)
> + * / ((1 << div_exp) * 256))
> + */
> + div_exp = 0;
> + exponent = 0;
> + mantissa = NIX_TM_MAX_RATE_MANTISSA;
> +
> + while (value <= (NIX_TM_SHAPER_RATE_CONST / (1 << div_exp)))
> + div_exp += 1;
> +
> + while (value <= ((NIX_TM_SHAPER_RATE_CONST * (256 +
> mantissa)) /
> + ((1 << div_exp) * 256)))
> + mantissa -= 1;
Please move this as another static function.
> + } else {
> + /* Calculate rate exponent and mantissa using
> + * the following formula:
> + *
> + * value = (2E6 * ((256 + mantissa) << exponent)) / 256
> + *
> + */
> + div_exp = 0;
> + exponent = NIX_TM_MAX_RATE_EXPONENT;
> + mantissa = NIX_TM_MAX_RATE_MANTISSA;
> +
> + while (value <= (NIX_TM_SHAPER_RATE_CONST * (1 << exponent)))
> + exponent -= 1;
> +
> + while (value <= ((NIX_TM_SHAPER_RATE_CONST *
> + ((256 + mantissa) << exponent)) /
> + 256))
> + mantissa -= 1;
Please move this as another static function.
> + }
> +
> + if (div_exp > NIX_TM_MAX_RATE_DIV_EXP ||
> + exponent > NIX_TM_MAX_RATE_EXPONENT ||
> + mantissa > NIX_TM_MAX_RATE_MANTISSA)
> + return 0;
> +
> + if (div_exp_p)
> + *div_exp_p = div_exp;
> + if (exponent_p)
> + *exponent_p = exponent;
> + if (mantissa_p)
> + *mantissa_p = mantissa;
> +
> + /* Calculate real rate value */
> + return NIX_TM_SHAPER_RATE(exponent, mantissa, div_exp);
> +}
> +
> +static uint64_t
> +nix_tm_shaper_rate_conv_exact(uint64_t value, uint64_t *exponent_p,
> + uint64_t *mantissa_p, uint64_t *div_exp_p)
> {
> uint64_t div_exp, exponent, mantissa;
>
> @@ -188,6 +251,23 @@ nix_tm_shaper_rate_conv(uint64_t value, uint64_t
> *exponent_p,
> return NIX_TM_SHAPER_RATE(exponent, mantissa, div_exp);
> }
>
> +/* With zero accuracy we will tune parameters as defined by HW,
> + * non zero accuracy will keep the parameters close to lower values
> + * and make sure long term shaper rate will not exceed requested rate.
long-term
requested -> the requested
