TFTP transfers fail when tftpblocksize is set to 8192 or larger due to insufficient buffer resources for IP fragment reassembly.
Calculate PBUF_POOL_SIZE and IP_REASS_MAX_PBUFS dynamically based on CONFIG_TFTP_BLOCKSIZE using IP fragmentation boundaries (1480 usable bytes per fragment at 1500 MTU). The pool size includes headroom for TX, ARP, and protocol overhead, while ensuring PBUF_POOL_SIZE remains greater than IP_REASS_MAX_PBUFS as required by lwIP. Signed-off-by: Pranav Tilak <[email protected]> --- lib/lwip/u-boot/lwipopts.h | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/lib/lwip/u-boot/lwipopts.h b/lib/lwip/u-boot/lwipopts.h index e8a2c9d7a0a..4a1f8086673 100644 --- a/lib/lwip/u-boot/lwipopts.h +++ b/lib/lwip/u-boot/lwipopts.h @@ -65,7 +65,21 @@ #define MEM_ALIGNMENT 8 #define MEMP_NUM_TCP_SEG 16 + +/* IP fragmentation parameters for TFTP reassembly */ +#define IP_FRAG_MTU_USABLE 1480 +#define PBUF_POOL_HEADROOM 6 +#define PBUF_POOL_RESERVE 4 +#define TFTP_BLOCKSIZE_THRESHOLD 4096 + +#if defined(CONFIG_TFTP_BLOCKSIZE) && (CONFIG_TFTP_BLOCKSIZE > TFTP_BLOCKSIZE_THRESHOLD) +#define PBUF_POOL_SIZE (((CONFIG_TFTP_BLOCKSIZE + (IP_FRAG_MTU_USABLE - 1)) / \ + IP_FRAG_MTU_USABLE) + PBUF_POOL_HEADROOM) +#define IP_REASS_MAX_PBUFS (PBUF_POOL_SIZE - PBUF_POOL_RESERVE) +#else #define PBUF_POOL_SIZE 8 +#define IP_REASS_MAX_PBUFS 4 +#endif #define LWIP_ARP 1 #define ARP_TABLE_SIZE 4 @@ -76,7 +90,7 @@ #define IP_REASSEMBLY 1 #define IP_FRAG 1 #define IP_REASS_MAXAGE 3 -#define IP_REASS_MAX_PBUFS 4 + #define IP_FRAG_USES_STATIC_BUF 0 #define IP_DEFAULT_TTL 255 -- 2.34.1
