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[ Upstream commitbf9cf80cab] In commit99537d5c47("net: macb: Relocate mog_init_rings() callback from macb_mac_link_up() to macb_open()"), the mog_init_rings() callback was moved from macb_mac_link_up() to macb_open() to resolve a deadlock issue. However, this change introduced a tx/rx malfunction following phy link down and up events. The issue arises from a mismatch between the software queue->tx_head, queue->tx_tail, queue->rx_prepared_head, and queue->rx_tail values and the hardware's internal tx/rx queue pointers. According to the Zynq UltraScale TRM [1], when tx/rx is disabled, the internal tx queue pointer resets to the value in the tx queue base address register, while the internal rx queue pointer remains unchanged. The following is quoted from the Zynq UltraScale TRM: When transmit is disabled, with bit [3] of the network control register set low, the transmit-buffer queue pointer resets to point to the address indicated by the transmit-buffer queue base address register. Disabling receive does not have the same effect on the receive-buffer queue pointer. Additionally, there is no need to reset the RBQP and TBQP registers in a phy event callback. Therefore, move macb_init_buffers() to macb_open(). In a phy link up event, the only required action is to reset the tx software head and tail pointers to align with the hardware's behavior. [1] https://docs.amd.com/v/u/en-US/ug1085-zynq-ultrascale-trm Fixes:99537d5c47("net: macb: Relocate mog_init_rings() callback from macb_mac_link_up() to macb_open()") Signed-off-by: Kevin Hao <haokexin@gmail.com> Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260208-macb-init-ring-v1-1-939a32c14635@gmail.com Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>