stmmac: reorganize chain/ring modes removing Koptions

Previously we had two Koptions to decide if the stmmac
had to use either a ring or a chain to manage its descriptors.
This patch removes the Kernel configuration options and it allow us
to use the chain mode by passing a module option.
Ring mode continues to be the default.

Also with this patch, it will be easier to validate the driver built and
guarantee that all the two modes always compile fine.

Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 66 insertions, 28 deletions

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index d02b446037d..bbee6b32ed6 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -130,6 +130,13 @@ module_param(eee_timer, int, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(eee_timer, "LPI tx expiration time in msec");
 #define STMMAC_LPI_TIMER(x) (jiffies + msecs_to_jiffies(x))
 
+/* By default the driver will use the ring mode to manage tx and rx descriptors
+ * but passing this value so user can force to use the chain instead of the ring
+ */
+static unsigned int chain_mode;
+module_param(chain_mode, int, S_IRUGO);
+MODULE_PARM_DESC(chain_mode, "To use chain instead of ring mode");
+
 static irqreturn_t stmmac_interrupt(int irq, void *dev_id);
 
 #ifdef CONFIG_STMMAC_DEBUG_FS
@@ -514,17 +521,15 @@ static void init_dma_desc_rings(struct net_device *dev)
 	struct sk_buff *skb;
 	unsigned int txsize = priv->dma_tx_size;
 	unsigned int rxsize = priv->dma_rx_size;
-	unsigned int bfsize;
+	unsigned int bfsize = 0;
 	int dis_ic = 0;
-	int des3_as_data_buf = 0;
 
 	/* Set the max buffer size according to the DESC mode
 	 * and the MTU. Note that RING mode allows 16KiB bsize. */
-	bfsize = priv->hw->ring->set_16kib_bfsize(dev->mtu);
+	if (priv->mode == STMMAC_RING_MODE)
+		bfsize = priv->hw->ring->set_16kib_bfsize(dev->mtu);
 
-	if (bfsize == BUF_SIZE_16KiB)
-		des3_as_data_buf = 1;
-	else
+	if (bfsize < BUF_SIZE_16KiB)
 		bfsize = stmmac_set_bfsize(dev->mtu, priv->dma_buf_sz);
 
 	DBG(probe, INFO, "stmmac: txsize %d, rxsize %d, bfsize %d\n",
@@ -571,7 +576,9 @@ static void init_dma_desc_rings(struct net_device *dev)
 
 		p->des2 = priv->rx_skbuff_dma[i];
 
-		priv->hw->ring->init_desc3(des3_as_data_buf, p);
+		if ((priv->mode == STMMAC_RING_MODE) &&
+		    (bfsize == BUF_SIZE_16KiB))
+			priv->hw->ring->init_desc3(p);
 
 		DBG(probe, INFO, "[%p]\t[%p]\t[%x]\n", priv->rx_skbuff[i],
 			priv->rx_skbuff[i]->data, priv->rx_skbuff_dma[i]);
@@ -589,17 +596,20 @@ static void init_dma_desc_rings(struct net_device *dev)
 
 	/* In case of Chained mode this sets the des3 to the next
 	 * element in the chain */
-	priv->hw->ring->init_dma_chain(priv->dma_rx, priv->dma_rx_phy, rxsize);
-	priv->hw->ring->init_dma_chain(priv->dma_tx, priv->dma_tx_phy, txsize);
-
+	if (priv->mode == STMMAC_CHAIN_MODE) {
+		priv->hw->chain->init_dma_chain(priv->dma_rx, priv->dma_rx_phy,
+						rxsize);
+		priv->hw->chain->init_dma_chain(priv->dma_tx, priv->dma_tx_phy,
+						txsize);
+	}
 	priv->dirty_tx = 0;
 	priv->cur_tx = 0;
 
 	if (priv->use_riwt)
 		dis_ic = 1;
 	/* Clear the Rx/Tx descriptors */
-	priv->hw->desc->init_rx_desc(priv->dma_rx, rxsize, dis_ic);
-	priv->hw->desc->init_tx_desc(priv->dma_tx, txsize);
+	priv->hw->desc->init_rx_desc(priv->dma_rx, rxsize, dis_ic, priv->mode);
+	priv->hw->desc->init_tx_desc(priv->dma_tx, txsize, priv->mode);
 
 	if (netif_msg_hw(priv)) {
 		pr_info("RX descriptor ring:\n");
@@ -726,14 +736,15 @@ static void stmmac_tx_clean(struct stmmac_priv *priv)
 			dma_unmap_single(priv->device, p->des2,
 					 priv->hw->desc->get_tx_len(p),
 					 DMA_TO_DEVICE);
-		priv->hw->ring->clean_desc3(p);
+		if (priv->mode == STMMAC_RING_MODE)
+			priv->hw->ring->clean_desc3(p);
 
 		if (likely(skb != NULL)) {
 			dev_kfree_skb(skb);
 			priv->tx_skbuff[entry] = NULL;
 		}
 
-		priv->hw->desc->release_tx_desc(p);
+		priv->hw->desc->release_tx_desc(p, priv->mode);
 
 		priv->dirty_tx++;
 	}
@@ -778,7 +789,8 @@ static void stmmac_tx_err(struct stmmac_priv *priv)
 
 	priv->hw->dma->stop_tx(priv->ioaddr);
 	dma_free_tx_skbufs(priv);
-	priv->hw->desc->init_tx_desc(priv->dma_tx, priv->dma_tx_size);
+	priv->hw->desc->init_tx_desc(priv->dma_tx, priv->dma_tx_size,
+				     priv->mode);
 	priv->dirty_tx = 0;
 	priv->cur_tx = 0;
 	priv->hw->dma->start_tx(priv->ioaddr);
@@ -1190,7 +1202,7 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
 	struct stmmac_priv *priv = netdev_priv(dev);
 	unsigned int txsize = priv->dma_tx_size;
 	unsigned int entry;
-	int i, csum_insertion = 0;
+	int i, csum_insertion = 0, is_jumbo = 0;
 	int nfrags = skb_shinfo(skb)->nr_frags;
 	struct dma_desc *desc, *first;
 	unsigned int nopaged_len = skb_headlen(skb);
@@ -1236,15 +1248,27 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
 #endif
 	priv->tx_skbuff[entry] = skb;
 
-	if (priv->hw->ring->is_jumbo_frm(skb->len, priv->plat->enh_desc)) {
-		entry = priv->hw->ring->jumbo_frm(priv, skb, csum_insertion);
-		desc = priv->dma_tx + entry;
+	/* To program the descriptors according to the size of the frame */
+	if (priv->mode == STMMAC_RING_MODE) {
+		is_jumbo = priv->hw->ring->is_jumbo_frm(skb->len,
+							priv->plat->enh_desc);
+		if (unlikely(is_jumbo))
+			entry = priv->hw->ring->jumbo_frm(priv, skb,
+							  csum_insertion);
 	} else {
+		is_jumbo = priv->hw->chain->is_jumbo_frm(skb->len,
+							priv->plat->enh_desc);
+		if (unlikely(is_jumbo))
+			entry = priv->hw->chain->jumbo_frm(priv, skb,
+							   csum_insertion);
+	}
+	if (likely(!is_jumbo)) {
 		desc->des2 = dma_map_single(priv->device, skb->data,
 					nopaged_len, DMA_TO_DEVICE);
 		priv->hw->desc->prepare_tx_desc(desc, 1, nopaged_len,
-						csum_insertion);
-	}
+						csum_insertion, priv->mode);
+	} else
+		desc = priv->dma_tx + entry;
 
 	for (i = 0; i < nfrags; i++) {
 		const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
@@ -1257,7 +1281,8 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
 		desc->des2 = skb_frag_dma_map(priv->device, frag, 0, len,
 					      DMA_TO_DEVICE);
 		priv->tx_skbuff[entry] = NULL;
-		priv->hw->desc->prepare_tx_desc(desc, 0, len, csum_insertion);
+		priv->hw->desc->prepare_tx_desc(desc, 0, len, csum_insertion,
+						priv->mode);
 		wmb();
 		priv->hw->desc->set_tx_owner(desc);
 		wmb();
@@ -1338,7 +1363,8 @@ static inline void stmmac_rx_refill(struct stmmac_priv *priv)
 
 			(p + entry)->des2 = priv->rx_skbuff_dma[entry];
 
-			if (unlikely(priv->plat->has_gmac))
+			if (unlikely((priv->mode == STMMAC_RING_MODE) &&
+				     (priv->plat->has_gmac)))
 				priv->hw->ring->refill_desc3(bfsize, p + entry);
 
 			RX_DBG(KERN_INFO "\trefill entry #%d\n", entry);
@@ -1884,12 +1910,20 @@ static int stmmac_hw_init(struct stmmac_priv *priv)
 
 	priv->hw = mac;
 
-	/* To use the chained or ring mode */
-	priv->hw->ring = &ring_mode_ops;
-
 	/* Get and dump the chip ID */
 	priv->synopsys_id = stmmac_get_synopsys_id(priv);
 
+	/* To use the chained or ring mode */
+	if (chain_mode)	{
+		priv->hw->chain = &chain_mode_ops;
+		pr_info(" Chain mode enabled\n");
+		priv->mode = STMMAC_CHAIN_MODE;
+	} else {
+		priv->hw->ring = &ring_mode_ops;
+		pr_info(" Ring mode enabled\n");
+		priv->mode = STMMAC_RING_MODE;
+	}
+
 	/* Get the HW capability (new GMAC newer than 3.50a) */
 	priv->hw_cap_support = stmmac_get_hw_features(priv);
 	if (priv->hw_cap_support) {
@@ -2109,8 +2143,9 @@ int stmmac_suspend(struct net_device *ndev)
 	priv->hw->dma->stop_rx(priv->ioaddr);
 	/* Clear the Rx/Tx descriptors */
 	priv->hw->desc->init_rx_desc(priv->dma_rx, priv->dma_rx_size,
-				     dis_ic);
-	priv->hw->desc->init_tx_desc(priv->dma_tx, priv->dma_tx_size);
+				     dis_ic, priv->mode);
+	priv->hw->desc->init_tx_desc(priv->dma_tx, priv->dma_tx_size,
+				     priv->mode);
 
 	/* Enable Power down mode by programming the PMT regs */
 	if (device_may_wakeup(priv->device))
@@ -2249,6 +2284,9 @@ static int __init stmmac_cmdline_opt(char *str)
 		} else if (!strncmp(opt, "eee_timer:", 10)) {
 			if (kstrtoint(opt + 10, 0, &eee_timer))
 				goto err;
+		} else if (!strncmp(opt, "chain_mode:", 11)) {
+			if (kstrtoint(opt + 11, 0, &chain_mode))
+				goto err;
 		}
 	}
 	return 0;