From 733afb244d304839569e9b99d7b9360298403c99 Mon Sep 17 00:00:00 2001 From: Walter Heymans Date: Wed, 20 Apr 2022 15:46:39 +0200 Subject: [PATCH] net/nfp: update how max MTU is read MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The 'max_rx_pktlen' value was previously read from hardware, which was set by the running firmware. This caused confusion due to different meanings of 'MAX_MTU'. This patch updates the 'max_rx_pktlen' to the maximum value that the NFP NIC can support. The 'max_mtu' value that is read from hardware, is assigned to the 'dev_info->max_mtu' variable. If more layer 2 metadata must be used, the firmware can be updated to report a smaller 'max_mtu' value. The constant defined for NFP_FRAME_SIZE_MAX is derived for the maximum supported buffer size of 10240, minus 136 bytes that is reserved by the hardware and another 56 bytes reserved for expansion in firmware. This results in a usable maximum packet length of 10048 bytes. Signed-off-by: Walter Heymans Signed-off-by: Niklas Söderlund Reviewed-by: Louis Peens Reviewed-by: Chaoyong He Reviewed-by: Richard Donkin --- drivers/net/nfp/nfp_common.c | 11 ++++++++++- drivers/net/nfp/nfp_common.h | 3 +++ 2 files changed, 13 insertions(+), 1 deletion(-) diff --git a/drivers/net/nfp/nfp_common.c b/drivers/net/nfp/nfp_common.c index b26770dbfb..52fbda1a79 100644 --- a/drivers/net/nfp/nfp_common.c +++ b/drivers/net/nfp/nfp_common.c @@ -692,7 +692,16 @@ nfp_net_infos_get(struct rte_eth_dev *dev, struct rte_eth_dev_info *dev_info) dev_info->max_rx_queues = (uint16_t)hw->max_rx_queues; dev_info->max_tx_queues = (uint16_t)hw->max_tx_queues; dev_info->min_rx_bufsize = RTE_ETHER_MIN_MTU; - dev_info->max_rx_pktlen = hw->max_mtu; + /* + * The maximum rx packet length (max_rx_pktlen) is set to the + * maximum supported frame size that the NFP can handle. This + * includes layer 2 headers, CRC and other metadata that can + * optionally be used. + * The maximum layer 3 MTU (max_mtu) is read from hardware, + * which was set by the firmware loaded onto the card. + */ + dev_info->max_rx_pktlen = NFP_FRAME_SIZE_MAX; + dev_info->max_mtu = hw->max_mtu; /* Next should change when PF support is implemented */ dev_info->max_mac_addrs = 1; diff --git a/drivers/net/nfp/nfp_common.h b/drivers/net/nfp/nfp_common.h index 8b35fa119c..8db5ec23f8 100644 --- a/drivers/net/nfp/nfp_common.h +++ b/drivers/net/nfp/nfp_common.h @@ -98,6 +98,9 @@ struct nfp_net_adapter; /* Number of supported physical ports */ #define NFP_MAX_PHYPORTS 12 +/* Maximum supported NFP frame size (MTU + layer 2 headers) */ +#define NFP_FRAME_SIZE_MAX 10048 + #include #include -- 2.20.1