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cadence: Add LSO support.
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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: David S. Miller <davem@davemloft.net>
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Rafal Ozieblo authored and David S. Miller committed Nov 16, 2016
1 parent 0834899 commit 1629dd4
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Showing 2 changed files with 140 additions and 12 deletions.
138 changes: 126 additions & 12 deletions drivers/net/ethernet/cadence/macb.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand Down Expand Up @@ -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)
Expand Down Expand Up @@ -1223,22 +1228,36 @@ 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;
struct macb_tx_skb *tx_skb = NULL;
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];

Expand All @@ -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 */
Expand Down Expand Up @@ -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);
Expand All @@ -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
Expand All @@ -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 */
Expand All @@ -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,
Expand All @@ -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",
Expand All @@ -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;
}
Expand Down Expand Up @@ -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
Expand Down Expand Up @@ -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;
Expand Down
14 changes: 14 additions & 0 deletions drivers/net/ethernet/cadence/macb.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand Down Expand Up @@ -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)
Expand Down Expand Up @@ -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
Expand Down

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