Re: [PATCH net-next 05/13] net: macb: add no LSO capability (MACB_CAPS_NO_LSO)

Claudiu Beznea
2025-03-24T08:18:57Z

Hi, Theo,

On 21.03.2025 21:09, Théo Lebrun wrote:
> LSO is runtime-detected using the PBUF_LSO field inside register
> designcfg_debug6/GEM_DCFG6. Allow disabling that feature if it is
> broken by using struct macb_config->caps.
>
> Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
> ---
> drivers/net/ethernet/cadence/macb.h | 1 +
> drivers/net/ethernet/cadence/macb_main.c | 5 +++--
> 2 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h
> index 3b43cb9468e3618754ff2bc6c5f360447bdeeed0..e9da6e3b869fc772613a0d6b86308917c9bff7fe 100644
> --- a/drivers/net/ethernet/cadence/macb.h
> +++ b/drivers/net/ethernet/cadence/macb.h
> @@ -739,6 +739,7 @@
> #define MACB_CAPS_MIIONRGMII BIT(9)
> #define MACB_CAPS_NEED_TSUCLK BIT(10)
> #define MACB_CAPS_QUEUE_DISABLE BIT(11)
> +#define MACB_CAPS_NO_LSO BIT(12)
> #define MACB_CAPS_PCS BIT(24)
> #define MACB_CAPS_HIGH_SPEED BIT(25)
> #define MACB_CAPS_CLK_HW_CHG BIT(26)
> diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
> index b5797c1ac0a41e9472883b013c1e44a01092f257..807f7abbd9941bf624f14a5ddead68dad1c8deb2 100644
> --- a/drivers/net/ethernet/cadence/macb_main.c
> +++ b/drivers/net/ethernet/cadence/macb_main.c
> @@ -4373,8 +4373,9 @@ static int macb_init(struct platform_device *pdev)
> /* Set features */
> dev->hw_features = NETIF_F_SG;
>
> - /* Check LSO capability */
> - if (GEM_BFEXT(PBUF_LSO, gem_readl(bp, DCFG6)))
> + /* Check LSO capability; capability is for buggy HW */

The comment here is a bit confusing to me.

> + if (!(bp->caps & MACB_CAPS_NO_LSO) &&
> + GEM_BFEXT(PBUF_LSO, gem_readl(bp, DCFG6)))
> dev->hw_features |= MACB_NETIF_LSO;
>
> /* Checksum offload is only available on gem with packet buffer */