net: stmmac: ethtool: Comment the magic numbers in RIWT computation

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Receive Interrupt Watchdog Timer is an RX interrupt coalescing mechanism
used by some variants of dwmac. It allows waiting a bit before
triggering the rx interrupts, allowing for batch processing.

The RIWT is configured with a granularity of 256 stmmac clk ticks. Let's
add a comment for that and wrap the raw "1000000" into USEC_PER_SEC, as
we're computing "how many clock cycles in one microsec" with that step.

Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20260802114015.214212-2-maxime.chevallier@bootlin.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

...

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Maxime Chevallier 2026-08-02 13:40:13 +02:00 • committed by Jakub Kicinski

parent c98610c2eb

commit b6a89c8ef3

1 changed files with 5 additions and 2 deletions

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drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c

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