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Commit 1629dd4f authored by Rafal Ozieblo's avatar Rafal Ozieblo Committed by David S. Miller
Browse files

cadence: Add LSO support. 



New Cadence GEM hardware support Large Segment Offload (LSO):
TCP segmentation offload (TSO) as well as UDP fragmentation
offload (UFO). Support for those features was added to the driver.

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 08348995

drivers/net/ethernet/cadence/macb.c

+126 −12
Original line number Diff line number Diff line
@@ -32,7 +32,9 @@ 
#include <linux/of_gpio.h>

#include <linux/of_mdio.h>

#include <linux/of_net.h>



#include <linux/ip.h>

#include <linux/udp.h>

#include <linux/tcp.h>

#include "macb.h"



#define MACB_RX_BUFFER_SIZE	128
@@ -60,10 +62,13 @@ 
					| MACB_BIT(TXERR))

#define MACB_TX_INT_FLAGS	(MACB_TX_ERR_FLAGS | MACB_BIT(TCOMP))



#define MACB_MAX_TX_LEN		((unsigned int)((1 << MACB_TX_FRMLEN_SIZE) - 1))

#define GEM_MAX_TX_LEN		((unsigned int)((1 << GEM_TX_FRMLEN_SIZE) - 1))

/* Max length of transmit frame must be a multiple of 8 bytes */

#define MACB_TX_LEN_ALIGN	8

#define MACB_MAX_TX_LEN		((unsigned int)((1 << MACB_TX_FRMLEN_SIZE) - 1) & ~((unsigned int)(MACB_TX_LEN_ALIGN - 1)))

#define GEM_MAX_TX_LEN		((unsigned int)((1 << GEM_TX_FRMLEN_SIZE) - 1) & ~((unsigned int)(MACB_TX_LEN_ALIGN - 1)))



#define GEM_MTU_MIN_SIZE	ETH_MIN_MTU

#define MACB_NETIF_LSO		(NETIF_F_TSO | NETIF_F_UFO)



#define MACB_WOL_HAS_MAGIC_PACKET	(0x1 << 0)

#define MACB_WOL_ENABLED		(0x1 << 1)
@@ -1223,7 +1228,8 @@ static void macb_poll_controller(struct net_device *dev) 


static unsigned int macb_tx_map(struct macb *bp,

				struct macb_queue *queue,

				struct sk_buff *skb)

				struct sk_buff *skb,

				unsigned int hdrlen)

{

	dma_addr_t mapping;

	unsigned int len, entry, i, tx_head = queue->tx_head;
@@ -1231,14 +1237,27 @@ static unsigned int macb_tx_map(struct macb *bp, 
	struct macb_dma_desc *desc;

	unsigned int offset, size, count = 0;

	unsigned int f, nr_frags = skb_shinfo(skb)->nr_frags;

	unsigned int eof = 1;

	u32 ctrl;

	unsigned int eof = 1, mss_mfs = 0;

	u32 ctrl, lso_ctrl = 0, seq_ctrl = 0;



	/* LSO */

	if (skb_shinfo(skb)->gso_size != 0) {

		if (ip_hdr(skb)->protocol == IPPROTO_UDP)

			/* UDP - UFO */

			lso_ctrl = MACB_LSO_UFO_ENABLE;

		else

			/* TCP - TSO */

			lso_ctrl = MACB_LSO_TSO_ENABLE;

	}



	/* First, map non-paged data */

	len = skb_headlen(skb);



	/* first buffer length */

	size = hdrlen;



	offset = 0;

	while (len) {

		size = min(len, bp->max_tx_length);

		entry = macb_tx_ring_wrap(bp, tx_head);

		tx_skb = &queue->tx_skb[entry];
@@ -1258,6 +1277,8 @@ static unsigned int macb_tx_map(struct macb *bp, 
		offset += size;

		count++;

		tx_head++;



		size = min(len, bp->max_tx_length);

	}



	/* Then, map paged data from fragments */
@@ -1311,6 +1332,21 @@ static unsigned int macb_tx_map(struct macb *bp, 
	desc = &queue->tx_ring[entry];

	desc->ctrl = ctrl;



	if (lso_ctrl) {

		if (lso_ctrl == MACB_LSO_UFO_ENABLE)

			/* include header and FCS in value given to h/w */

			mss_mfs = skb_shinfo(skb)->gso_size +

					skb_transport_offset(skb) +

					ETH_FCS_LEN;

		else /* TSO */ {

			mss_mfs = skb_shinfo(skb)->gso_size;

			/* TCP Sequence Number Source Select

			 * can be set only for TSO

			 */

			seq_ctrl = 0;

		}

	}



	do {

		i--;

		entry = macb_tx_ring_wrap(bp, i);
@@ -1325,6 +1361,16 @@ static unsigned int macb_tx_map(struct macb *bp, 
		if (unlikely(entry == (bp->tx_ring_size - 1)))

			ctrl |= MACB_BIT(TX_WRAP);



		/* First descriptor is header descriptor */

		if (i == queue->tx_head) {

			ctrl |= MACB_BF(TX_LSO, lso_ctrl);

			ctrl |= MACB_BF(TX_TCP_SEQ_SRC, seq_ctrl);

		} else

			/* Only set MSS/MFS on payload descriptors

			 * (second or later descriptor)

			 */

			ctrl |= MACB_BF(MSS_MFS, mss_mfs);



		/* Set TX buffer descriptor */

		macb_set_addr(desc, tx_skb->mapping);

		/* desc->addr must be visible to hardware before clearing
@@ -1350,6 +1396,43 @@ static unsigned int macb_tx_map(struct macb *bp, 
	return 0;

}



static netdev_features_t macb_features_check(struct sk_buff *skb,

					     struct net_device *dev,

					     netdev_features_t features)

{

	unsigned int nr_frags, f;

	unsigned int hdrlen;



	/* Validate LSO compatibility */



	/* there is only one buffer */

	if (!skb_is_nonlinear(skb))

		return features;



	/* length of header */

	hdrlen = skb_transport_offset(skb);

	if (ip_hdr(skb)->protocol == IPPROTO_TCP)

		hdrlen += tcp_hdrlen(skb);



	/* For LSO:

	 * When software supplies two or more payload buffers all payload buffers

	 * apart from the last must be a multiple of 8 bytes in size.

	 */

	if (!IS_ALIGNED(skb_headlen(skb) - hdrlen, MACB_TX_LEN_ALIGN))

		return features & ~MACB_NETIF_LSO;



	nr_frags = skb_shinfo(skb)->nr_frags;

	/* No need to check last fragment */

	nr_frags--;

	for (f = 0; f < nr_frags; f++) {

		const skb_frag_t *frag = &skb_shinfo(skb)->frags[f];



		if (!IS_ALIGNED(skb_frag_size(frag), MACB_TX_LEN_ALIGN))

			return features & ~MACB_NETIF_LSO;

	}

	return features;

}



static inline int macb_clear_csum(struct sk_buff *skb)

{

	/* no change for packets without checksum offloading */
@@ -1374,7 +1457,28 @@ static int macb_start_xmit(struct sk_buff *skb, struct net_device *dev) 
	struct macb *bp = netdev_priv(dev);

	struct macb_queue *queue = &bp->queues[queue_index];

	unsigned long flags;

	unsigned int count, nr_frags, frag_size, f;

	unsigned int desc_cnt, nr_frags, frag_size, f;

	unsigned int hdrlen;

	bool is_lso, is_udp = 0;



	is_lso = (skb_shinfo(skb)->gso_size != 0);



	if (is_lso) {

		is_udp = !!(ip_hdr(skb)->protocol == IPPROTO_UDP);



		/* length of headers */

		if (is_udp)

			/* only queue eth + ip headers separately for UDP */

			hdrlen = skb_transport_offset(skb);

		else

			hdrlen = skb_transport_offset(skb) + tcp_hdrlen(skb);

		if (skb_headlen(skb) < hdrlen) {

			netdev_err(bp->dev, "Error - LSO headers fragmented!!!\n");

			/* if this is required, would need to copy to single buffer */

			return NETDEV_TX_BUSY;

		}

	} else

		hdrlen = min(skb_headlen(skb), bp->max_tx_length);



#if defined(DEBUG) && defined(VERBOSE_DEBUG)

	netdev_vdbg(bp->dev,
@@ -1389,18 +1493,22 @@ static int macb_start_xmit(struct sk_buff *skb, struct net_device *dev) 
	 * socket buffer: skb fragments of jumbo frames may need to be

	 * split into many buffer descriptors.

	 */

	count = DIV_ROUND_UP(skb_headlen(skb), bp->max_tx_length);

	if (is_lso && (skb_headlen(skb) > hdrlen))

		/* extra header descriptor if also payload in first buffer */

		desc_cnt = DIV_ROUND_UP((skb_headlen(skb) - hdrlen), bp->max_tx_length) + 1;

	else

		desc_cnt = DIV_ROUND_UP(skb_headlen(skb), bp->max_tx_length);

	nr_frags = skb_shinfo(skb)->nr_frags;

	for (f = 0; f < nr_frags; f++) {

		frag_size = skb_frag_size(&skb_shinfo(skb)->frags[f]);

		count += DIV_ROUND_UP(frag_size, bp->max_tx_length);

		desc_cnt += DIV_ROUND_UP(frag_size, bp->max_tx_length);

	}



	spin_lock_irqsave(&bp->lock, flags);



	/* This is a hard error, log it. */

	if (CIRC_SPACE(queue->tx_head, queue->tx_tail,

		       bp->tx_ring_size) < count) {

		       bp->tx_ring_size) < desc_cnt) {

		netif_stop_subqueue(dev, queue_index);

		spin_unlock_irqrestore(&bp->lock, flags);

		netdev_dbg(bp->dev, "tx_head = %u, tx_tail = %u\n",
@@ -1414,7 +1522,7 @@ static int macb_start_xmit(struct sk_buff *skb, struct net_device *dev) 
	}



	/* Map socket buffer for DMA transfer */

	if (!macb_tx_map(bp, queue, skb)) {

	if (!macb_tx_map(bp, queue, skb, hdrlen)) {

		dev_kfree_skb_any(skb);

		goto unlock;

	}
@@ -2354,6 +2462,7 @@ static const struct net_device_ops macb_netdev_ops = { 
	.ndo_poll_controller	= macb_poll_controller,

#endif

	.ndo_set_features	= macb_set_features,

	.ndo_features_check	= macb_features_check,

};



/* Configure peripheral capabilities according to device tree
@@ -2560,6 +2669,11 @@ static int macb_init(struct platform_device *pdev) 


	/* Set features */

	dev->hw_features = NETIF_F_SG;



	/* Check LSO capability */

	if (GEM_BFEXT(PBUF_LSO, gem_readl(bp, DCFG6)))

		dev->hw_features |= MACB_NETIF_LSO;



	/* Checksum offload is only available on gem with packet buffer */

	if (macb_is_gem(bp) && !(bp->caps & MACB_CAPS_FIFO_MODE))

		dev->hw_features |= NETIF_F_HW_CSUM | NETIF_F_RXCSUM;

drivers/net/ethernet/cadence/macb.h

+14 −0
Original line number Diff line number Diff line
@@ -382,6 +382,10 @@ 
#define GEM_TX_PKT_BUFF_OFFSET			21

#define GEM_TX_PKT_BUFF_SIZE			1



/* Bitfields in DCFG6. */

#define GEM_PBUF_LSO_OFFSET			27

#define GEM_PBUF_LSO_SIZE			1



/* Constants for CLK */

#define MACB_CLK_DIV8				0

#define MACB_CLK_DIV16				1
@@ -414,6 +418,10 @@ 
#define MACB_CAPS_SG_DISABLED			0x40000000

#define MACB_CAPS_MACB_IS_GEM			0x80000000



/* LSO settings */

#define MACB_LSO_UFO_ENABLE			0x01

#define MACB_LSO_TSO_ENABLE			0x02



/* Bit manipulation macros */

#define MACB_BIT(name)					\

	(1 << MACB_##name##_OFFSET)
@@ -545,6 +553,12 @@ struct macb_dma_desc { 
#define MACB_TX_LAST_SIZE			1

#define MACB_TX_NOCRC_OFFSET			16

#define MACB_TX_NOCRC_SIZE			1

#define MACB_MSS_MFS_OFFSET			16

#define MACB_MSS_MFS_SIZE			14

#define MACB_TX_LSO_OFFSET			17

#define MACB_TX_LSO_SIZE			2

#define MACB_TX_TCP_SEQ_SRC_OFFSET		19

#define MACB_TX_TCP_SEQ_SRC_SIZE		1

#define MACB_TX_BUF_EXHAUSTED_OFFSET		27

#define MACB_TX_BUF_EXHAUSTED_SIZE		1

#define MACB_TX_UNDERRUN_OFFSET			28