[PATCH] myri10ge: add page-based skb routines

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>

1 files changed, 190 insertions, 0 deletions

diff --git a/drivers/net/myri10ge/myri10ge.c b/drivers/net/myri10ge/myri10ge.c
index 1e62f58ed2c2..05b4f93518f5 100644
--- a/drivers/net/myri10ge/myri10ge.c
+++ b/drivers/net/myri10ge/myri10ge.c
@@ -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)
 };
@@ -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 {
@@ -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;
@@ -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)
@@ -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)