net: bcmasp: fix memory leak when bringing down interface

When bringing down the TX rings we flush the rings but forget to
reclaimed the flushed packets. This leads to a memory leak since we
do not free the dma mapped buffers. This also leads to tx control
block corruption when bringing down the interface for power
management.

Fixes: 490cb412 ("net: bcmasp: Add support for ASP2.0 Ethernet controller")
Signed-off-by: Justin Chen <justin.chen@broadcom.com>
Acked-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20240418180541.2271719-1-justin.chen@broadcom.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/broadcom/asp2/bcmasp_intf.c

@@ -436,10 +436,8 @@ static void umac_init(struct bcmasp_intf *intf)
 	umac_wl(intf, 0x800, UMC_RX_MAX_PKT_SZ);
 }
 
-static int bcmasp_tx_poll(struct napi_struct *napi, int budget)
+static int bcmasp_tx_reclaim(struct bcmasp_intf *intf)
 {
-	struct bcmasp_intf *intf =
-		container_of(napi, struct bcmasp_intf, tx_napi);
 	struct bcmasp_intf_stats64 *stats = &intf->stats64;
 	struct device *kdev = &intf->parent->pdev->dev;
 	unsigned long read, released = 0;
@@ -482,10 +480,16 @@ static int bcmasp_tx_poll(struct napi_struct *napi, int budget)
 							DESC_RING_COUNT);
 	}
 
-	/* Ensure all descriptors have been written to DRAM for the hardware
-	 * to see updated contents.
-	 */
-	wmb();
+	return released;
+}
+
+static int bcmasp_tx_poll(struct napi_struct *napi, int budget)
+{
+	struct bcmasp_intf *intf =
+		container_of(napi, struct bcmasp_intf, tx_napi);
+	int released = 0;
+
+	released = bcmasp_tx_reclaim(intf);
 
 	napi_complete(&intf->tx_napi);
 
@@ -797,6 +801,7 @@ static void bcmasp_init_tx(struct bcmasp_intf *intf)
 	intf->tx_spb_dma_read = intf->tx_spb_dma_addr;
 	intf->tx_spb_index = 0;
 	intf->tx_spb_clean_index = 0;
+	memset(intf->tx_cbs, 0, sizeof(struct bcmasp_tx_cb) * DESC_RING_COUNT);
 
 	/* Make sure channels are disabled */
 	tx_spb_ctrl_wl(intf, 0x0, TX_SPB_CTRL_ENABLE);
@@ -885,6 +890,8 @@ static void bcmasp_netif_deinit(struct net_device *dev)
 	} while (timeout-- > 0);
 	tx_spb_dma_wl(intf, 0x0, TX_SPB_DMA_FIFO_CTRL);
 
+	bcmasp_tx_reclaim(intf);
+
 	umac_enable_set(intf, UMC_CMD_TX_EN, 0);
 
 	phy_stop(dev->phydev);