On Wed, 11 Mar 2026 17:41:54 +0100 Théo Lebrun wrote:

GEM has registers to configure the Tx SRAM segments distribution across
queues. The reset value is apprioriate (even spread) but we need to
care if/when number of active queues is modified (or if we inherited
unevenly initialised hardware from bootloader).

To distribute segments, we take as input the number of queues
(bp->num_queues) and the number of segments (found inside DCFG6).
Its output is a number of segments for each queue, formatted as
powers-of-two (eg 2 for queue 0 means it has 2^2=4 segments)

allmodconfig builds are not happy with whatever is going on here:

ld.lld: error: undefined symbol: gem_sram_distribute_segments

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referenced by macb_kunit.c:13 (drivers/net/ethernet/cadence/macb_kunit.c:13)
              vmlinux.o:(macb_sram_segments_test)
referenced by macb_kunit.c:51 (drivers/net/ethernet/cadence/macb_kunit.c:51)
              vmlinux.o:(macb_sram_segments_gen_params)

ld.lld: error: undefined symbol: kunit_binary_assert_format

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referenced by macb_kunit.c:29 (drivers/net/ethernet/cadence/macb_kunit.c:29)
              vmlinux.o:(macb_sram_segments_test)
referenced by macb_kunit.c:34 (drivers/net/ethernet/cadence/macb_kunit.c:34)
              vmlinux.o:(macb_sram_segments_test)

ld.lld: error: undefined symbol: __kunit_do_failed_assertion

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referenced by macb_kunit.c:29 (drivers/net/ethernet/cadence/macb_kunit.c:29)
              vmlinux.o:(macb_sram_segments_test)
referenced by macb_kunit.c:34 (drivers/net/ethernet/cadence/macb_kunit.c:34)
              vmlinux.o:(macb_sram_segments_test)

ld.lld: error: undefined symbol: __kunit_abort

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referenced by macb_kunit.c:29 (drivers/net/ethernet/cadence/macb_kunit.c:29)
              vmlinux.o:(macb_sram_segments_test)
referenced by macb_kunit.c:34 (drivers/net/ethernet/cadence/macb_kunit.c:34)
              vmlinux.o:(macb_sram_segments_test)