fman_port_cf...efix_content(9)

💅 fman_port_cfg_buf_prefix_content(9) 💅

okay so this is a page from the Kernel API Manual, and bestie, the function name is a mouthful: fman_port_cfg_buf_prefix_content. say it with me now. no cap, it's giving "someone fell asleep on the keyboard" energy, but we're gonna get through it together 🫶

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✨ NAME ✨

fman_port_cfg_buf_prefix_content

that's literally it, that's the whole NAME section — no one-liner blurb, no little dash of description. iconic minimalism honestly 💅

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🌸 SYNOPSIS 🌸

int fman_port_cfg_buf_prefix_content (struct fman_port *port , struct
       fman_buffer_prefix_content * buffer_prefix_content );

so she takes a port and she takes a buffer_prefix_content, and she returns an int. simple as that. slay.

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🎀 ARGUMENTS 🎀

• port — a pointer to a FM Port module. a pointer, bestie. handle with care 🙈
• buffer_prefix_content — a structure of parameters describing the structure of the buffer. yes, structure of the structure. we love a recursive vibe check ✨

okay so here's the deets on this one, and I'm gonna be real with you, the original wording here is a little feral, so stay with me:

Out parameter: Start margin — offset of data from start of external buffer. she defines the structure, size and content of the application buffer.

about the prefix, in Tx ports: if 'pass_prs_result', the application should set a value to their offsets in the prefix of the FM will save the first (in this order), to the application buffer, and to offset. 😭 yeah I know. that's what it says. I'm not gonna pretend it's a clean sentence, but every word of it matters so there it is, untouched.

calling this routine changes the buffer margins definitions in the internal driver data base from its default configuration:

• Data size: [DEFAULT_PORT_BUFFER_PREFIX_CONTENT_PRIV_DATA_SIZE]
• Pass Parser result: [DEFAULT_PORT_BUFFER_PREFIX_CONTENT_PASS_PRS_RESULT]
• Pass timestamp: [DEFAULT_PORT_BUFFER_PREFIX_CONTENT_PASS_TIME_STAMP]

and bestie — this one may be used for all ports 👑 all of them. every single one.

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🦋 DESCRIPTION 🦋

⚠️ timing check, queen: this is allowed only following fman_port_config and before fman_port_init.

so if you've already called fman_port_init, you are LOWKEY too late and it's not gonna happen. order matters. main character energy requires a schedule 💀

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🔥 RETURN 🔥

• 0 on success 🎉
• Error code otherwise 😭

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🌈 SEE ALSO 🌈

• The kernel file ./drivers/net/ethernet/freescale/fman/fman_port.c — go read the source, iykyk 🧚
• fman_port_config(9)
• fman_port_init(9)
• fman_port_disable(9)
• fman_port_enable(9)
• fman_port_bind(9)
• fman_port_get_qman_channel_id(9)
• fman_port_get_device(9)

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and that's the whole page, bestie 💖 this one lives in ./drivers/net/ethernet/freesca... and the version stamp is dated October 2026, so like... future vibes only 🌸⭐ go forth and configure your buffer prefix content with confidence, you got this 🫶💜