pasemi_mac: jumbo frame support

First cut at jumbo frame support. To support large MTU, one or several
separate channels must be allocated to calculate the TCP/UDP checksum
separately, since the mac lacks enough buffers to hold a whole packet
while it's being calculated.

Furthermore, it seems that a single function channel is not quite
enough to feed one of the 10Gig links, so allocate two channels for
XAUI interfaces.

Signed-off-by: Olof Johansson <olof@lixom.net>
Acked-by: Jeff Garzik <jgarzik@pobox.com>

2 files changed, 275 insertions, 34 deletions

diff --git a/drivers/net/pasemi_mac.c b/drivers/net/pasemi_mac.c
index 6ea822addde5..54904ad29ea7 100644
--- a/drivers/net/pasemi_mac.c
+++ b/drivers/net/pasemi_mac.c
@@ -59,11 +59,12 @@
 /* Must be a power of two */
 #define RX_RING_SIZE 2048
 #define TX_RING_SIZE 4096
+#define CS_RING_SIZE (TX_RING_SIZE*2)
 
 #define LRO_MAX_AGGR 64
 
 #define PE_MIN_MTU      64
-#define PE_MAX_MTU      1500
+#define PE_MAX_MTU      9000
 #define PE_DEF_MTU      ETH_DATA_LEN
 
 #define DEFAULT_MSG_ENABLE        \
@@ -81,6 +82,7 @@
 #define RX_DESC(rx, num)        ((rx)->chan.ring_virt[(num) & (RX_RING_SIZE-1)])
 #define RX_DESC_INFO(rx, num)   ((rx)->ring_info[(num) & (RX_RING_SIZE-1)])
 #define RX_BUFF(rx, num)        ((rx)->buffers[(num) & (RX_RING_SIZE-1)])
+#define CS_DESC(cs, num)        ((cs)->chan.ring_virt[(num) & (CS_RING_SIZE-1)])
 
 #define RING_USED(ring)         (((ring)->next_to_fill - (ring)->next_to_clean) \
                                  & ((ring)->size - 1))
@@ -322,6 +324,103 @@ static int pasemi_mac_unmap_tx_skb(struct pasemi_mac *mac,
         return (nfrags + 3) & ~1;
 }
 
+static struct pasemi_mac_csring *pasemi_mac_setup_csring(struct pasemi_mac *mac)
+{
+        struct pasemi_mac_csring *ring;
+        u32 val;
+        unsigned int cfg;
+        int chno;
+
+        ring = pasemi_dma_alloc_chan(TXCHAN, sizeof(struct pasemi_mac_csring),
+                                       offsetof(struct pasemi_mac_csring, chan));
+
+        if (!ring) {
+                dev_err(&mac->pdev->dev, "Can't allocate checksum channel\n");
+                goto out_chan;
+        }
+
+        chno = ring->chan.chno;
+
+        ring->size = CS_RING_SIZE;
+        ring->next_to_fill = 0;
+
+        /* Allocate descriptors */
+        if (pasemi_dma_alloc_ring(&ring->chan, CS_RING_SIZE))
+                goto out_ring_desc;
+
+        write_dma_reg(PAS_DMA_TXCHAN_BASEL(chno),
+                      PAS_DMA_TXCHAN_BASEL_BRBL(ring->chan.ring_dma));
+        val = PAS_DMA_TXCHAN_BASEU_BRBH(ring->chan.ring_dma >> 32);
+        val |= PAS_DMA_TXCHAN_BASEU_SIZ(CS_RING_SIZE >> 3);
+
+        write_dma_reg(PAS_DMA_TXCHAN_BASEU(chno), val);
+
+        ring->events[0] = pasemi_dma_alloc_flag();
+        ring->events[1] = pasemi_dma_alloc_flag();
+        if (ring->events[0] < 0 || ring->events[1] < 0)
+                goto out_flags;
+
+        pasemi_dma_clear_flag(ring->events[0]);
+        pasemi_dma_clear_flag(ring->events[1]);
+
+        ring->fun = pasemi_dma_alloc_fun();
+        if (ring->fun < 0)
+                goto out_fun;
+
+        cfg = PAS_DMA_TXCHAN_CFG_TY_FUNC | PAS_DMA_TXCHAN_CFG_UP |
+              PAS_DMA_TXCHAN_CFG_TATTR(ring->fun) |
+              PAS_DMA_TXCHAN_CFG_LPSQ | PAS_DMA_TXCHAN_CFG_LPDQ;
+
+        if (translation_enabled())
+                cfg |= PAS_DMA_TXCHAN_CFG_TRD | PAS_DMA_TXCHAN_CFG_TRR;
+
+        write_dma_reg(PAS_DMA_TXCHAN_CFG(chno), cfg);
+
+        /* enable channel */
+        pasemi_dma_start_chan(&ring->chan, PAS_DMA_TXCHAN_TCMDSTA_SZ |
+                                           PAS_DMA_TXCHAN_TCMDSTA_DB |
+                                           PAS_DMA_TXCHAN_TCMDSTA_DE |
+                                           PAS_DMA_TXCHAN_TCMDSTA_DA);
+
+        return ring;
+
+out_fun:
+out_flags:
+        if (ring->events[0] >= 0)
+                pasemi_dma_free_flag(ring->events[0]);
+        if (ring->events[1] >= 0)
+                pasemi_dma_free_flag(ring->events[1]);
+        pasemi_dma_free_ring(&ring->chan);
+out_ring_desc:
+        pasemi_dma_free_chan(&ring->chan);
+out_chan:
+
+        return NULL;
+}
+
+static void pasemi_mac_setup_csrings(struct pasemi_mac *mac)
+{
+        int i;
+        mac->cs[0] = pasemi_mac_setup_csring(mac);
+        if (mac->type == MAC_TYPE_XAUI)
+                mac->cs[1] = pasemi_mac_setup_csring(mac);
+        else
+                mac->cs[1] = 0;
+
+        for (i = 0; i < MAX_CS; i++)
+                if (mac->cs[i])
+                        mac->num_cs++;
+}
+
+static void pasemi_mac_free_csring(struct pasemi_mac_csring *csring)
+{
+        pasemi_dma_stop_chan(&csring->chan);
+        pasemi_dma_free_flag(csring->events[0]);
+        pasemi_dma_free_flag(csring->events[1]);
+        pasemi_dma_free_ring(&csring->chan);
+        pasemi_dma_free_chan(&csring->chan);
+}
+
 static int pasemi_mac_setup_rx_resources(const struct net_device *dev)
 {
         struct pasemi_mac_rxring *ring;
@@ -445,7 +544,7 @@ pasemi_mac_setup_tx_resources(const struct net_device *dev)
         cfg = PAS_DMA_TXCHAN_CFG_TY_IFACE |
               PAS_DMA_TXCHAN_CFG_TATTR(mac->dma_if) |
               PAS_DMA_TXCHAN_CFG_UP |
-              PAS_DMA_TXCHAN_CFG_WT(2);
+              PAS_DMA_TXCHAN_CFG_WT(4);
 
         if (translation_enabled())
                 cfg |= PAS_DMA_TXCHAN_CFG_TRD | PAS_DMA_TXCHAN_CFG_TRR;
@@ -810,13 +909,21 @@ restart:
                 u64 mactx = TX_DESC(txring, i);
                 struct sk_buff *skb;
 
-                skb = TX_DESC_INFO(txring, i+1).skb;
-                nr_frags = TX_DESC_INFO(txring, i).dma;
-
                 if ((mactx  & XCT_MACTX_E) ||
                     (*chan->status & PAS_STATUS_ERROR))
                         pasemi_mac_tx_error(mac, mactx);
 
+                /* Skip over control descriptors */
+                if (!(mactx & XCT_MACTX_LLEN_M)) {
+                        TX_DESC(txring, i) = 0;
+                        TX_DESC(txring, i+1) = 0;
+                        buf_count = 2;
+                        continue;
+                }
+
+                skb = TX_DESC_INFO(txring, i+1).skb;
+                nr_frags = TX_DESC_INFO(txring, i).dma;
+
                 if (unlikely(mactx & XCT_MACTX_O))
                         /* Not yet transmitted */
                         break;
@@ -1058,6 +1165,12 @@ static int pasemi_mac_open(struct net_device *dev)
         if (!mac->tx)
                 goto out_tx_ring;
 
+        if (dev->mtu > 1500) {
+                pasemi_mac_setup_csrings(mac);
+                if (!mac->num_cs)
+                        goto out_tx_ring;
+        }
+
         /* 0x3ff with 33MHz clock is about 31us */
         write_iob_reg(PAS_IOB_DMA_COM_TIMEOUTCFG,
                       PAS_IOB_DMA_COM_TIMEOUTCFG_TCNT(0x3ff));
@@ -1241,7 +1354,7 @@ static int pasemi_mac_close(struct net_device *dev)
 {
         struct pasemi_mac *mac = netdev_priv(dev);
         unsigned int sta;
-        int rxch, txch;
+        int rxch, txch, i;
 
         rxch = rx_ring(mac)->chan.chno;
         txch = tx_ring(mac)->chan.chno;
@@ -1286,6 +1399,9 @@ static int pasemi_mac_close(struct net_device *dev)
         free_irq(mac->tx->chan.irq, mac->tx);
         free_irq(mac->rx->chan.irq, mac->rx);
 
+        for (i = 0; i < mac->num_cs; i++)
+                pasemi_mac_free_csring(mac->cs[i]);
+
         /* Free resources */
         pasemi_mac_free_rx_resources(mac);
         pasemi_mac_free_tx_resources(mac);
@@ -1293,35 +1409,113 @@ static int pasemi_mac_close(struct net_device *dev)
         return 0;
 }
 
+static void pasemi_mac_queue_csdesc(const struct sk_buff *skb,
+                                    const dma_addr_t *map,
+                                    const unsigned int *map_size,
+                                    struct pasemi_mac_txring *txring,
+                                    struct pasemi_mac_csring *csring)
+{
+        u64 fund;
+        dma_addr_t cs_dest;
+        const int nh_off = skb_network_offset(skb);
+        const int nh_len = skb_network_header_len(skb);
+        const int nfrags = skb_shinfo(skb)->nr_frags;
+        int cs_size, i, fill, hdr, cpyhdr, evt;
+        dma_addr_t csdma;
+
+        fund = XCT_FUN_ST | XCT_FUN_RR_8BRES |
+               XCT_FUN_O | XCT_FUN_FUN(csring->fun) |
+               XCT_FUN_CRM_SIG | XCT_FUN_LLEN(skb->len - nh_off) |
+               XCT_FUN_SHL(nh_len >> 2) | XCT_FUN_SE;
+
+        switch (ip_hdr(skb)->protocol) {
+        case IPPROTO_TCP:
+                fund |= XCT_FUN_SIG_TCP4;
+                /* TCP checksum is 16 bytes into the header */
+                cs_dest = map[0] + skb_transport_offset(skb) + 16;
+                break;
+        case IPPROTO_UDP:
+                fund |= XCT_FUN_SIG_UDP4;
+                /* UDP checksum is 6 bytes into the header */
+                cs_dest = map[0] + skb_transport_offset(skb) + 6;
+                break;
+        default:
+                BUG();
+        }
+
+        /* Do the checksum offloaded */
+        fill = csring->next_to_fill;
+        hdr = fill;
+
+        CS_DESC(csring, fill++) = fund;
+        /* Room for 8BRES. Checksum result is really 2 bytes into it */
+        csdma = csring->chan.ring_dma + (fill & (CS_RING_SIZE-1)) * 8 + 2;
+        CS_DESC(csring, fill++) = 0;
+
+        CS_DESC(csring, fill) = XCT_PTR_LEN(map_size[0]-nh_off) | XCT_PTR_ADDR(map[0]+nh_off);
+        for (i = 1; i <= nfrags; i++)
+                CS_DESC(csring, fill+i) = XCT_PTR_LEN(map_size[i]) | XCT_PTR_ADDR(map[i]);
+
+        fill += i;
+        if (fill & 1)
+                fill++;
+
+        /* Copy the result into the TCP packet */
+        cpyhdr = fill;
+        CS_DESC(csring, fill++) = XCT_FUN_O | XCT_FUN_FUN(csring->fun) |
+                                  XCT_FUN_LLEN(2) | XCT_FUN_SE;
+        CS_DESC(csring, fill++) = XCT_PTR_LEN(2) | XCT_PTR_ADDR(cs_dest) | XCT_PTR_T;
+        CS_DESC(csring, fill++) = XCT_PTR_LEN(2) | XCT_PTR_ADDR(csdma);
+        fill++;
+
+        evt = !csring->last_event;
+        csring->last_event = evt;
+
+        /* Event handshaking with MAC TX */
+        CS_DESC(csring, fill++) = CTRL_CMD_T | CTRL_CMD_META_EVT | CTRL_CMD_O |
+                                  CTRL_CMD_ETYPE_SET | CTRL_CMD_REG(csring->events[evt]);
+        CS_DESC(csring, fill++) = 0;
+        CS_DESC(csring, fill++) = CTRL_CMD_T | CTRL_CMD_META_EVT | CTRL_CMD_O |
+                                  CTRL_CMD_ETYPE_WCLR | CTRL_CMD_REG(csring->events[!evt]);
+        CS_DESC(csring, fill++) = 0;
+        csring->next_to_fill = fill & (CS_RING_SIZE-1);
+
+        cs_size = fill - hdr;
+        write_dma_reg(PAS_DMA_TXCHAN_INCR(csring->chan.chno), (cs_size) >> 1);
+
+        /* TX-side event handshaking */
+        fill = txring->next_to_fill;
+        TX_DESC(txring, fill++) = CTRL_CMD_T | CTRL_CMD_META_EVT | CTRL_CMD_O |
+                                  CTRL_CMD_ETYPE_WSET | CTRL_CMD_REG(csring->events[evt]);
+        TX_DESC(txring, fill++) = 0;
+        TX_DESC(txring, fill++) = CTRL_CMD_T | CTRL_CMD_META_EVT | CTRL_CMD_O |
+                                  CTRL_CMD_ETYPE_CLR | CTRL_CMD_REG(csring->events[!evt]);
+        TX_DESC(txring, fill++) = 0;
+        txring->next_to_fill = fill;
+
+        write_dma_reg(PAS_DMA_TXCHAN_INCR(txring->chan.chno), 2);
+
+        return;
+}
+
 static int pasemi_mac_start_tx(struct sk_buff *skb, struct net_device *dev)
 {
-        struct pasemi_mac *mac = netdev_priv(dev);
-        struct pasemi_mac_txring *txring;
-        u64 dflags, mactx;
+        struct pasemi_mac * const mac = netdev_priv(dev);
+        struct pasemi_mac_txring * const txring = tx_ring(mac);
+        struct pasemi_mac_csring *csring;
+        u64 dflags = 0;
+        u64 mactx;
         dma_addr_t map[MAX_SKB_FRAGS+1];
         unsigned int map_size[MAX_SKB_FRAGS+1];
         unsigned long flags;
         int i, nfrags;
         int fill;
+        const int nh_off = skb_network_offset(skb);
+        const int nh_len = skb_network_header_len(skb);
 
-        dflags = XCT_MACTX_O | XCT_MACTX_ST | XCT_MACTX_CRC_PAD;
-
-        if (skb->ip_summed == CHECKSUM_PARTIAL) {
-                const unsigned char *nh = skb_network_header(skb);
+        prefetch(&txring->ring_info);
 
-                switch (ip_hdr(skb)->protocol) {
-                case IPPROTO_TCP:
-                        dflags |= XCT_MACTX_CSUM_TCP;
-                        dflags |= XCT_MACTX_IPH(skb_network_header_len(skb) >> 2);
-                        dflags |= XCT_MACTX_IPO(nh - skb->data);
-                        break;
-                case IPPROTO_UDP:
-                        dflags |= XCT_MACTX_CSUM_UDP;
-                        dflags |= XCT_MACTX_IPH(skb_network_header_len(skb) >> 2);
-                        dflags |= XCT_MACTX_IPO(nh - skb->data);
-                        break;
-                }
-        }
+        dflags = XCT_MACTX_O | XCT_MACTX_ST | XCT_MACTX_CRC_PAD;
 
         nfrags = skb_shinfo(skb)->nr_frags;
 
@@ -1344,24 +1538,46 @@ static int pasemi_mac_start_tx(struct sk_buff *skb, struct net_device *dev)
                 }
         }
 
-        mactx = dflags | XCT_MACTX_LLEN(skb->len);
+        if (skb->ip_summed == CHECKSUM_PARTIAL && skb->len <= 1540) {
+                switch (ip_hdr(skb)->protocol) {
+                case IPPROTO_TCP:
+                        dflags |= XCT_MACTX_CSUM_TCP;
+                        dflags |= XCT_MACTX_IPH(nh_len >> 2);
+                        dflags |= XCT_MACTX_IPO(nh_off);
+                        break;
+                case IPPROTO_UDP:
+                        dflags |= XCT_MACTX_CSUM_UDP;
+                        dflags |= XCT_MACTX_IPH(nh_len >> 2);
+                        dflags |= XCT_MACTX_IPO(nh_off);
+                        break;
+                default:
+                        WARN_ON(1);
+                }
+        }
 
-        txring = tx_ring(mac);
+        mactx = dflags | XCT_MACTX_LLEN(skb->len);
 
         spin_lock_irqsave(&txring->lock, flags);
 
-        fill = txring->next_to_fill;
-
         /* Avoid stepping on the same cache line that the DMA controller
          * is currently about to send, so leave at least 8 words available.
          * Total free space needed is mactx + fragments + 8
          */
-        if (RING_AVAIL(txring) < nfrags + 10) {
+        if (RING_AVAIL(txring) < nfrags + 14) {
                 /* no room -- stop the queue and wait for tx intr */
                 netif_stop_queue(dev);
                 goto out_err;
         }
 
+        /* Queue up checksum + event descriptors, if needed */
+        if (mac->num_cs && skb->ip_summed == CHECKSUM_PARTIAL && skb->len > 1540) {
+                csring = mac->cs[mac->last_cs];
+                mac->last_cs = (mac->last_cs + 1) % mac->num_cs;
+
+                pasemi_mac_queue_csdesc(skb, map, map_size, txring, csring);
+        }
+
+        fill = txring->next_to_fill;
         TX_DESC(txring, fill) = mactx;
         TX_DESC_INFO(txring, fill).dma = nfrags;
         fill++;
@@ -1439,8 +1655,9 @@ static int pasemi_mac_change_mtu(struct net_device *dev, int new_mtu)
 {
         struct pasemi_mac *mac = netdev_priv(dev);
         unsigned int reg;
-        unsigned int rcmdsta;
+        unsigned int rcmdsta = 0;
         int running;
+        int ret = 0;
 
         if (new_mtu < PE_MIN_MTU || new_mtu > PE_MAX_MTU)
                 return -EINVAL;
@@ -1462,6 +1679,16 @@ static int pasemi_mac_change_mtu(struct net_device *dev, int new_mtu)
                 pasemi_mac_pause_rxint(mac);
                 pasemi_mac_clean_rx(rx_ring(mac), RX_RING_SIZE);
                 pasemi_mac_free_rx_buffers(mac);
+
+        }
+
+        /* Setup checksum channels if large MTU and none already allocated */
+        if (new_mtu > 1500 && !mac->num_cs) {
+                pasemi_mac_setup_csrings(mac);
+                if (!mac->num_cs) {
+                        ret = -ENOMEM;
+                        goto out;
+                }
         }
 
         /* Change maxf, i.e. what size frames are accepted.
@@ -1476,6 +1703,7 @@ static int pasemi_mac_change_mtu(struct net_device *dev, int new_mtu)
         /* MTU + ETH_HLEN + VLAN_HLEN + 2 64B cachelines */
         mac->bufsz = new_mtu + ETH_HLEN + ETH_FCS_LEN + LOCAL_SKB_ALIGN + 128;
 
+out:
         if (running) {
                 write_dma_reg(PAS_DMA_RXINT_RCMDSTA(mac->dma_if),
                               rcmdsta | PAS_DMA_RXINT_RCMDSTA_EN);
@@ -1488,7 +1716,7 @@ static int pasemi_mac_change_mtu(struct net_device *dev, int new_mtu)
                 pasemi_mac_intf_enable(mac);
         }
 
-        return 0;
+        return ret;
 }
 
 static int __devinit
diff --git a/drivers/net/pasemi_mac.h b/drivers/net/pasemi_mac.h
index 99e7b9329a6f..90c51670a1e7 100644
--- a/drivers/net/pasemi_mac.h
+++ b/drivers/net/pasemi_mac.h
@@ -27,6 +27,7 @@
 #include <linux/phy.h>
 
 #define MAX_LRO_DESCRIPTORS 8
+#define MAX_CS  2
 
 struct pasemi_mac_txring {
         struct pasemi_dmachan chan; /* Must be first */
@@ -51,6 +52,15 @@ struct pasemi_mac_rxring {
         struct pasemi_mac *mac; /* Needed in intr handler */
 };
 
+struct pasemi_mac_csring {
+        struct pasemi_dmachan chan;
+        unsigned int    size;
+        unsigned int    next_to_fill;
+        int             events[2];
+        int             last_event;
+        int             fun;
+};
+
 struct pasemi_mac {
         struct net_device *netdev;
         struct pci_dev *pdev;
@@ -60,10 +70,12 @@ struct pasemi_mac {
         struct napi_struct napi;
 
         int             bufsz; /* RX ring buffer size */
+        int             last_cs;
+        int             num_cs;
+        u32             dma_if;
         u8              type;
 #define MAC_TYPE_GMAC   1
 #define MAC_TYPE_XAUI   2
-        u32     dma_if;
 
         u8              mac_addr[6];
 
@@ -74,6 +86,7 @@ struct pasemi_mac {
 
         struct pasemi_mac_txring *tx;
         struct pasemi_mac_rxring *rx;
+        struct pasemi_mac_csring *cs[MAX_CS];
         char            tx_irq_name[10];                /* "eth%d tx" */
         char            rx_irq_name[10];                /* "eth%d rx" */
         int     link;