Re: [PATCH net 11/12] net: systemport: Update TDMA queue mapping dynamically on changeupper

When DSA upper devices are dynamically attached or detached while the
master SYSTEMPORT interface is already up and running (netif_running()),
bcm_sysport_map_queues() and bcm_sysport_unmap_queues() updated the
internal software mappings but did not update the TDMA_DESC_RING_MAPPING
hardware registers, because programming was previously deferred until
bcm_sysport_init_tx_ring().

Update TDMA_DESC_RING_MAPPING registers immediately if netif_running()
is true during map_queues and unmap_queues.

Fixes: 1593cd40d785 ("net: systemport: use standard netdevice notifier to detect DSA presence")
Assisted-by: LLM
Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>
---
 drivers/net/ethernet/broadcom/bcmsysport.c | 23 +++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bcmsysport.c b/drivers/net/ethernet/broadcom/bcmsysport.c
index dd5a7c9dd90f..e5bb7fa84fda 100644
--- a/drivers/net/ethernet/broadcom/bcmsysport.c
+++ b/drivers/net/ethernet/broadcom/bcmsysport.c

@@ -2390,6 +2399,14 @@ static int bcm_sysport_unmap_queues(struct net_device *dev,
 		qp = ring->switch_queue;
 		if (qp + port * num_tx_queues < ARRAY_SIZE(priv->ring_map))
 			priv->ring_map[qp + port * num_tx_queues] = NULL;
+
+		if (netif_running(dev)) {
+			reg = tdma_readl(priv, TDMA_DESC_RING_MAPPING(q));
+			reg &= ~(RING_QID_MASK |
+				 RING_PORT_ID_MASK << RING_PORT_ID_SHIFT);
+			reg |= RING_IGNORE_STATUS;
+			tdma_writel(priv, reg, TDMA_DESC_RING_MAPPING(q));
+		}