net: macb: allocate tieoff descriptor once across device lifetime

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The tieoff descriptor is a RX DMA descriptor ring of size one. It gets
configured onto queues for Wake-on-LAN during system-wide suspend when
hardware does not support disabling individual queues
(MACB_CAPS_QUEUE_DISABLE).

MACB/GEM driver allocates it alongside the main RX ring
inside macb_alloc() at open. Free is done by macb_free() at close.

Change to allocate once at probe and free on probe failure or device
removal. This makes the tieoff descriptor lifetime much longer,
avoiding repeating coherent buffer allocation on each open/close cycle.

Main benefit: we dissociate its lifetime from the main ring's lifetime.
That way there is less work to be doing on resources (re)alloc. This
currently happens on close/open, but will soon also happen on context
swap operations (set_ringparam, change_mtu, set_channels, etc).

Reviewed-by: Nicolai Buchwitz <nb@tipi-net.de>
Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
Link: https://patch.msgid.link/20260812-macb-context-v9-6-7ddbf5f715e0@bootlin.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

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Théo Lebrun 2026-08-12 10:03:20 +02:00 • committed by Jakub Kicinski

parent 2cedfce238

commit 5262eab946

1 changed files with 41 additions and 34 deletions

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drivers/net/ethernet/cadence/macb_main.c

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