[PATCH net 1/2] net: stmmac: Limit FIFO size by hardware feature value

[Furong Xu]

On Thu, 16 Jan 2025 11:08:52 +0900, Kunihiko Hayashi <hayashi.kunihiko at socionext.com> wrote:

> Tx/Rx FIFO size is specified by the parameter "{tx,rx}-fifo-depth" from
> the platform layer.
> 
> However, these values are constrained by upper limits determined by the
> capabilities of each hardware feature. There is a risk that the upper
> bits will be truncated due to the calculation, so it's appropriate to
> limit them to the upper limit values.
> 

Patch is fine, but the Fixes: tag is required here.

And if you like to group this patch and the another patch into one series,
it is better to add a cover letter.

> Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko at socionext.com>
> ---
>  drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> index 7bf275f127c9..2d69c3c4b329 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -2375,9 +2375,9 @@ static void stmmac_dma_operation_mode(struct stmmac_priv *priv)
>  	u32 chan = 0;
>  	u8 qmode = 0;
>  
> -	if (rxfifosz == 0)
> +	if (!rxfifosz || rxfifosz > priv->dma_cap.rx_fifo_size)
>  		rxfifosz = priv->dma_cap.rx_fifo_size;
> -	if (txfifosz == 0)
> +	if (!txfifosz || txfifosz > priv->dma_cap.tx_fifo_size)
>  		txfifosz = priv->dma_cap.tx_fifo_size;
>  
>  	/* Split up the shared Tx/Rx FIFO memory on DW QoS Eth and DW XGMAC */
> @@ -2851,9 +2851,9 @@ static void stmmac_set_dma_operation_mode(struct stmmac_priv *priv, u32 txmode,
>  	int rxfifosz = priv->plat->rx_fifo_size;
>  	int txfifosz = priv->plat->tx_fifo_size;
>  
> -	if (rxfifosz == 0)
> +	if (!rxfifosz || rxfifosz > priv->dma_cap.rx_fifo_size)
>  		rxfifosz = priv->dma_cap.rx_fifo_size;
> -	if (txfifosz == 0)
> +	if (!txfifosz || txfifosz > priv->dma_cap.tx_fifo_size)
>  		txfifosz = priv->dma_cap.tx_fifo_size;
>  
>  	/* Adjust for real per queue fifo size */