pdc_build_rxd(9)

💅 pdc_build_rxd(9) — from the Kernel API Manual, bestie

okay so picture this: you're in the kernel, specifically hanging out in the mailbox neighborhood, and you need a DMA descriptor that's literally built for catching the SPU's result. That's the whole ~vibe~ of this function. It's called pdc_build_rxd and it builds a DMA descriptor to receive an SPU result. Short, sweet, iconic, no notes. 🎀

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✨ SYNOPSIS ✨

void pdc_build_rxd (struct pdc_state *pdcs , dma_addr_t dma_addr , u32
buf_len , u32 flags );

like, that's it. that's the whole signature. she's a void, she returns nothing, she just does the thing and leaves. main character energy fr fr 💅

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🫶 ARGUMENTS 🫶

• pdcs — the PDC state for the SPU that's gonna generate the result. basically the ✨context✨ of the whole situation, so hand her the right one.
• dma_addr — the DMA address of the buffer this descriptor is being built for. yes, that buffer. the one you're describing. 🦋
• buf_len — how long the receive buffer is, in bytes. keep it accurate, bestie, this is a length not a suggestion.
• flags — the flags that get stored in the descriptor. they go in the descriptor. they live there now. 🏠

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🌈 SEE ALSO 🌈

this is the friend group, and honestly they're all linked so you never get lost:

Kernel file ./drivers/mailbox/bcm-pdc-mailbox.c — the whole squad lives here:

• pdc_setup_debugfs(9)
• pdc_build_txd(9)
• pdc_receive_one(9)
• pdc_receive(9)
• pdc_tx_list_sg_add(9)
• pdc_tx_list_final(9)
• pdc_rx_list_init(9)
• pdc_rx_list_sg_add(9)
• pdc_irq_handler(9)
• pdc_work_cb(9)
• pdc_ring_init(9)
• pdc_desc_count(9)
• pdc_rings_full(9)
• pdc_last_tx_done(9)
• pdc_send_data(9)
• pdc_hw_init(9)
• pdc_hw_disable(9)
• pdc_rx_buf_pool_create(9)
• pdc_interrupts_init(9)
• pdc_mb_init(9)
• pdc_dt_read(9)
• pdc_probe(9)

go read them, they ate. 🔥

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lowkey a reminder that the Rx side has its own build function (pdc_build_rxd) and the Tx side has its own (pdc_build_txd) — don't mix up your girls, they do different jobs 💀

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and that's the page! brought to you by the fine folks over in ./drivers/mailbox, dated October 2026, and catalogued forever as pdc_build_rxd(9). slay and goodbye 👑💖