net: stmmac: Add support to Ethtool get/set ring parameters

This patch add support to --show-ring & --set-ring Ethtool functions:
- Adding min, max, power of two check to new ring parameter's value.
- Bring down the network interface before changing the value of ring
  parameters.
- Bring up the network interface after changing the value of ring
  parameters.

Signed-off-by: Song, Yoong Siang <yoong.siang.song@intel.com>
Signed-off-by: Voon Weifeng <weifeng.voon@intel.com>
Signed-off-by: Ong Boon Leong <boon.leong.ong@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Author: yoongsiang2

drivers/net/ethernet/stmicro/stmmac/chain_mode.c

@@ -46,7 +46,7 @@ static int jumbo_frm(void *p, struct sk_buff *skb, int csum)
 
 	while (len != 0) {
 		tx_q->tx_skbuff[entry] = NULL;
-		entry = STMMAC_GET_ENTRY(entry, DMA_TX_SIZE);
+		entry = STMMAC_GET_ENTRY(entry, priv->dma_tx_size);
 		desc = tx_q->dma_tx + entry;
 
 		if (len > bmax) {
@@ -137,7 +137,7 @@ static void refill_desc3(void *priv_ptr, struct dma_desc *p)
 		 */
 		p->des3 = cpu_to_le32((unsigned int)(rx_q->dma_rx_phy +
 				      (((rx_q->dirty_rx) + 1) %
-				       DMA_RX_SIZE) *
+				       priv->dma_rx_size) *
 				      sizeof(struct dma_desc)));
 }
 
@@ -154,7 +154,8 @@ static void clean_desc3(void *priv_ptr, struct dma_desc *p)
 		 * to keep explicit chaining in the descriptor.
 		 */
 		p->des3 = cpu_to_le32((unsigned int)((tx_q->dma_tx_phy +
-				      ((tx_q->dirty_tx + 1) % DMA_TX_SIZE))
+				      ((tx_q->dirty_tx + 1) %
+				       priv->dma_tx_size))
 				      * sizeof(struct dma_desc)));
 }
 

drivers/net/ethernet/stmicro/stmmac/common.h

@@ -42,9 +42,16 @@
 
 #define STMMAC_CHAN0	0	/* Always supported and default for all chips */
 
-/* These need to be power of two, and >= 4 */
-#define DMA_TX_SIZE 512
-#define DMA_RX_SIZE 512
+/* TX and RX Descriptor Length, these need to be power of two.
+ * TX descriptor length less than 64 may cause transmit queue timed out error.
+ * RX descriptor length less than 64 may cause inconsistent Rx chain error.
+ */
+#define DMA_MIN_TX_SIZE		64
+#define DMA_MAX_TX_SIZE		1024
+#define DMA_DEFAULT_TX_SIZE	512
+#define DMA_MIN_RX_SIZE		64
+#define DMA_MAX_RX_SIZE		1024
+#define DMA_DEFAULT_RX_SIZE	512
 #define STMMAC_GET_ENTRY(x, size)	((x + 1) & (size - 1))
 
 #undef FRAME_FILTER_DEBUG

drivers/net/ethernet/stmicro/stmmac/ring_mode.c

@@ -51,7 +51,7 @@ static int jumbo_frm(void *p, struct sk_buff *skb, int csum)
 		stmmac_prepare_tx_desc(priv, desc, 1, bmax, csum,
 				STMMAC_RING_MODE, 0, false, skb->len);
 		tx_q->tx_skbuff[entry] = NULL;
-		entry = STMMAC_GET_ENTRY(entry, DMA_TX_SIZE);
+		entry = STMMAC_GET_ENTRY(entry, priv->dma_tx_size);
 
 		if (priv->extend_desc)
 			desc = (struct dma_desc *)(tx_q->dma_etx + entry);

drivers/net/ethernet/stmicro/stmmac/stmmac.h

@@ -171,9 +171,11 @@ struct stmmac_priv {
 
 	/* RX Queue */
 	struct stmmac_rx_queue rx_queue[MTL_MAX_RX_QUEUES];
+	unsigned int dma_rx_size;
 
 	/* TX Queue */
 	struct stmmac_tx_queue tx_queue[MTL_MAX_TX_QUEUES];
+	unsigned int dma_tx_size;
 
 	/* Generic channel for NAPI */
 	struct stmmac_channel channel[STMMAC_CH_MAX];
@@ -265,6 +267,7 @@ int stmmac_dvr_probe(struct device *device,
 void stmmac_disable_eee_mode(struct stmmac_priv *priv);
 bool stmmac_eee_init(struct stmmac_priv *priv);
 int stmmac_reinit_queues(struct net_device *dev, u32 rx_cnt, u32 tx_cnt);
+int stmmac_reinit_ringparam(struct net_device *dev, u32 rx_size, u32 tx_size);
 
 #if IS_ENABLED(CONFIG_STMMAC_SELFTESTS)
 void stmmac_selftest_run(struct net_device *dev,

drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c

@@ -440,6 +440,33 @@ static int stmmac_nway_reset(struct net_device *dev)
 	return phylink_ethtool_nway_reset(priv->phylink);
 }
 
+static void stmmac_get_ringparam(struct net_device *netdev,
+				 struct ethtool_ringparam *ring)
+{
+	struct stmmac_priv *priv = netdev_priv(netdev);
+
+	ring->rx_max_pending = DMA_MAX_RX_SIZE;
+	ring->tx_max_pending = DMA_MAX_TX_SIZE;
+	ring->rx_pending = priv->dma_rx_size;
+	ring->tx_pending = priv->dma_tx_size;
+}
+
+static int stmmac_set_ringparam(struct net_device *netdev,
+				struct ethtool_ringparam *ring)
+{
+	if (ring->rx_mini_pending || ring->rx_jumbo_pending ||
+	    ring->rx_pending < DMA_MIN_RX_SIZE ||
+	    ring->rx_pending > DMA_MAX_RX_SIZE ||
+	    !is_power_of_2(ring->rx_pending) ||
+	    ring->tx_pending < DMA_MIN_TX_SIZE ||
+	    ring->tx_pending > DMA_MAX_TX_SIZE ||
+	    !is_power_of_2(ring->tx_pending))
+		return -EINVAL;
+
+	return stmmac_reinit_ringparam(netdev, ring->rx_pending,
+				       ring->tx_pending);
+}
+
 static void
 stmmac_get_pauseparam(struct net_device *netdev,
 		      struct ethtool_pauseparam *pause)
@@ -947,6 +974,8 @@ static const struct ethtool_ops stmmac_ethtool_ops = {
 	.get_regs_len = stmmac_ethtool_get_regs_len,
 	.get_link = ethtool_op_get_link,
 	.nway_reset = stmmac_nway_reset,
+	.get_ringparam = stmmac_get_ringparam,
+	.set_ringparam = stmmac_set_ringparam,
 	.get_pauseparam = stmmac_get_pauseparam,
 	.set_pauseparam = stmmac_set_pauseparam,
 	.self_test = stmmac_selftest_run,