check-dma

name	check-dma
description	Verify PL→PS data moves by DMA, not single-beat Xil_In32/staging loops. Run before declaring any PL↔PS data-transfer task done in the MicroZedIntanInterface firmware.

check-dma

Guardrail for the PL→PS data path. Rule: bulk PL→PS data MUST move by AXI CDMA, landed straight into the pbuf payload. The cleanest form is: the PL builds the whole wire packet (header + payload) in its result BRAM, and the PS just DMAs it into the pbuf and sends — exactly as the broadband path does (the PL writes the 10-word header in data_generator_core.sv). The PS must never loop over BRAM (Xil_In32) or over the DMA staging buffer to move bulk samples.

How to run

bash scripts/check_dma.sh [firmware_dir]      # default: firmware

It flags two single-beat patterns and exits non-zero on any un-justified one:

• A — single-beat BRAM: Xil_In32/Xil_Out32 of a *BRAM* address.
• B — staging CPU read: = ...staging...[...] (the PS reading the DMA'd copy word-by-word).

Isolated control/status-register accesses (PL_CTRL_BASE_ADDR + CTRL_REG/STATUS_REG) are not flagged — those are small config, not bulk data.

Resolving a VIOLATION

1. Preferred: convert it to DMA-into-pbuf (or have the PL build the packet in BRAM and just DMA+send it). Then it stops matching and the check passes.
2. If genuinely justified (e.g. a 2-word magic/resync peek, or the single-beat reference reader behind BRAM_READ_METHOD): annotate the same line with // DMA-EXEMPT: <reason>. The check then reports it as exempt and passes.

When to run

Before telling the user any PL↔PS data-transfer change is done. If you added a new single-beat site, you must convert it to DMA or justify it with a DMA-EXEMPT annotation — don't ship an un-justified single-beat bulk transfer.