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[PATCH] myri10ge: add page-based skb routines
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Add physical page skb allocation routines and page based rx_done,
to be used by upcoming patches.

Signed-off-by: Brice Goglin <brice@myri.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
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Brice Goglin authored and Jeff Garzik committed Dec 11, 2006
1 parent 6250223 commit dd50f33
Showing 1 changed file with 190 additions and 0 deletions.
190 changes: 190 additions & 0 deletions drivers/net/myri10ge/myri10ge.c
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Original file line number Diff line number Diff line change
Expand Up @@ -92,8 +92,14 @@ MODULE_LICENSE("Dual BSD/GPL");
#define MYRI10GE_NO_CONFIRM_DATA htonl(0xffffffff)
#define MYRI10GE_NO_RESPONSE_RESULT 0xffffffff

#define MYRI10GE_ALLOC_ORDER 0
#define MYRI10GE_ALLOC_SIZE ((1 << MYRI10GE_ALLOC_ORDER) * PAGE_SIZE)
#define MYRI10GE_MAX_FRAGS_PER_FRAME (MYRI10GE_MAX_ETHER_MTU/MYRI10GE_ALLOC_SIZE + 1)

struct myri10ge_rx_buffer_state {
struct sk_buff *skb;
struct page *page;
int page_offset;
DECLARE_PCI_UNMAP_ADDR(bus)
DECLARE_PCI_UNMAP_LEN(len)
};
Expand All @@ -116,9 +122,14 @@ struct myri10ge_rx_buf {
u8 __iomem *wc_fifo; /* w/c rx dma addr fifo address */
struct mcp_kreq_ether_recv *shadow; /* host shadow of recv ring */
struct myri10ge_rx_buffer_state *info;
struct page *page;
dma_addr_t bus;
int page_offset;
int cnt;
int fill_cnt;
int alloc_fail;
int mask; /* number of rx slots -1 */
int watchdog_needed;
};

struct myri10ge_tx_buf {
Expand Down Expand Up @@ -150,6 +161,7 @@ struct myri10ge_priv {
struct myri10ge_rx_buf rx_big;
struct myri10ge_rx_done rx_done;
int small_bytes;
int big_bytes;
struct net_device *dev;
struct net_device_stats stats;
u8 __iomem *sram;
Expand Down Expand Up @@ -266,6 +278,10 @@ static int myri10ge_debug = -1; /* defaults above */
module_param(myri10ge_debug, int, 0);
MODULE_PARM_DESC(myri10ge_debug, "Debug level (0=none,...,16=all)");

static int myri10ge_fill_thresh = 256;
module_param(myri10ge_fill_thresh, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(myri10ge_fill_thresh, "Number of empty rx slots allowed\n");

#define MYRI10GE_FW_OFFSET 1024*1024
#define MYRI10GE_HIGHPART_TO_U32(X) \
(sizeof (X) == 8) ? ((u32)((u64)(X) >> 32)) : (0)
Expand Down Expand Up @@ -958,6 +974,180 @@ static inline void myri10ge_vlan_ip_csum(struct sk_buff *skb, __wsum hw_csum)
}
}

static inline void
myri10ge_rx_skb_build(struct sk_buff *skb, u8 * va,
struct skb_frag_struct *rx_frags, int len, int hlen)
{
struct skb_frag_struct *skb_frags;

skb->len = skb->data_len = len;
skb->truesize = len + sizeof(struct sk_buff);
/* attach the page(s) */

skb_frags = skb_shinfo(skb)->frags;
while (len > 0) {
memcpy(skb_frags, rx_frags, sizeof(*skb_frags));
len -= rx_frags->size;
skb_frags++;
rx_frags++;
skb_shinfo(skb)->nr_frags++;
}

/* pskb_may_pull is not available in irq context, but
* skb_pull() (for ether_pad and eth_type_trans()) requires
* the beginning of the packet in skb_headlen(), move it
* manually */
memcpy(skb->data, va, hlen);
skb_shinfo(skb)->frags[0].page_offset += hlen;
skb_shinfo(skb)->frags[0].size -= hlen;
skb->data_len -= hlen;
skb->tail += hlen;
skb_pull(skb, MXGEFW_PAD);
}

static void
myri10ge_alloc_rx_pages(struct myri10ge_priv *mgp, struct myri10ge_rx_buf *rx,
int bytes, int watchdog)
{
struct page *page;
int idx;

if (unlikely(rx->watchdog_needed && !watchdog))
return;

/* try to refill entire ring */
while (rx->fill_cnt != (rx->cnt + rx->mask + 1)) {
idx = rx->fill_cnt & rx->mask;

if ((bytes < MYRI10GE_ALLOC_SIZE / 2) &&
(rx->page_offset + bytes <= MYRI10GE_ALLOC_SIZE)) {
/* we can use part of previous page */
get_page(rx->page);
} else {
/* we need a new page */
page =
alloc_pages(GFP_ATOMIC | __GFP_COMP,
MYRI10GE_ALLOC_ORDER);
if (unlikely(page == NULL)) {
if (rx->fill_cnt - rx->cnt < 16)
rx->watchdog_needed = 1;
return;
}
rx->page = page;
rx->page_offset = 0;
rx->bus = pci_map_page(mgp->pdev, page, 0,
MYRI10GE_ALLOC_SIZE,
PCI_DMA_FROMDEVICE);
}
rx->info[idx].page = rx->page;
rx->info[idx].page_offset = rx->page_offset;
/* note that this is the address of the start of the
* page */
pci_unmap_addr_set(&rx->info[idx], bus, rx->bus);
rx->shadow[idx].addr_low =
htonl(MYRI10GE_LOWPART_TO_U32(rx->bus) + rx->page_offset);
rx->shadow[idx].addr_high =
htonl(MYRI10GE_HIGHPART_TO_U32(rx->bus));

/* start next packet on a cacheline boundary */
rx->page_offset += SKB_DATA_ALIGN(bytes);
rx->fill_cnt++;

/* copy 8 descriptors to the firmware at a time */
if ((idx & 7) == 7) {
if (rx->wc_fifo == NULL)
myri10ge_submit_8rx(&rx->lanai[idx - 7],
&rx->shadow[idx - 7]);
else {
mb();
myri10ge_pio_copy(rx->wc_fifo,
&rx->shadow[idx - 7], 64);
}
}
}
}

static inline void
myri10ge_unmap_rx_page(struct pci_dev *pdev,
struct myri10ge_rx_buffer_state *info, int bytes)
{
/* unmap the recvd page if we're the only or last user of it */
if (bytes >= MYRI10GE_ALLOC_SIZE / 2 ||
(info->page_offset + 2 * bytes) > MYRI10GE_ALLOC_SIZE) {
pci_unmap_page(pdev, (pci_unmap_addr(info, bus)
& ~(MYRI10GE_ALLOC_SIZE - 1)),
MYRI10GE_ALLOC_SIZE, PCI_DMA_FROMDEVICE);
}
}

#define MYRI10GE_HLEN 64 /* The number of bytes to copy from a
* page into an skb */

static inline int
myri10ge_page_rx_done(struct myri10ge_priv *mgp, struct myri10ge_rx_buf *rx,
int bytes, int len, __wsum csum)
{
struct sk_buff *skb;
struct skb_frag_struct rx_frags[MYRI10GE_MAX_FRAGS_PER_FRAME];
int i, idx, hlen, remainder;
struct pci_dev *pdev = mgp->pdev;
struct net_device *dev = mgp->dev;
u8 *va;

len += MXGEFW_PAD;
idx = rx->cnt & rx->mask;
va = page_address(rx->info[idx].page) + rx->info[idx].page_offset;
prefetch(va);
/* Fill skb_frag_struct(s) with data from our receive */
for (i = 0, remainder = len; remainder > 0; i++) {
myri10ge_unmap_rx_page(pdev, &rx->info[idx], bytes);
rx_frags[i].page = rx->info[idx].page;
rx_frags[i].page_offset = rx->info[idx].page_offset;
if (remainder < MYRI10GE_ALLOC_SIZE)
rx_frags[i].size = remainder;
else
rx_frags[i].size = MYRI10GE_ALLOC_SIZE;
rx->cnt++;
idx = rx->cnt & rx->mask;
remainder -= MYRI10GE_ALLOC_SIZE;
}

hlen = MYRI10GE_HLEN > len ? len : MYRI10GE_HLEN;

/* allocate an skb to attach the page(s) to. */

skb = netdev_alloc_skb(dev, MYRI10GE_HLEN + 16);
if (unlikely(skb == NULL)) {
mgp->stats.rx_dropped++;
do {
i--;
put_page(rx_frags[i].page);
} while (i != 0);
return 0;
}

/* Attach the pages to the skb, and trim off any padding */
myri10ge_rx_skb_build(skb, va, rx_frags, len, hlen);
if (skb_shinfo(skb)->frags[0].size <= 0) {
put_page(skb_shinfo(skb)->frags[0].page);
skb_shinfo(skb)->nr_frags = 0;
}
skb->protocol = eth_type_trans(skb, dev);
skb->dev = dev;

if (mgp->csum_flag) {
if ((skb->protocol == htons(ETH_P_IP)) ||
(skb->protocol == htons(ETH_P_IPV6))) {
skb->csum = csum;
skb->ip_summed = CHECKSUM_COMPLETE;
} else
myri10ge_vlan_ip_csum(skb, csum);
}
netif_receive_skb(skb);
dev->last_rx = jiffies;
return 1;
}

static inline unsigned long
myri10ge_rx_done(struct myri10ge_priv *mgp, struct myri10ge_rx_buf *rx,
int bytes, int len, __wsum csum)
Expand Down

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