3c59x: Use fine-grained locks for MII and windowed register access
authorBen Hutchings <ben@decadent.org.uk>
Tue, 29 Jun 2010 15:26:56 +0000 (15:26 +0000)
committerDavid S. Miller <davem@davemloft.net>
Wed, 30 Jun 2010 06:14:21 +0000 (23:14 -0700)
This avoids scheduling in atomic context and also means that IRQs
will only be deferred for relatively short periods of time.

Previously discussed in:
http://article.gmane.org/gmane.linux.network/155024

Reported-by: Arne Nordmark <nordmark@mech.kth.se>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
drivers/net/3c59x.c

index beddef98ad9249144426f99bdf04b97c15e8935f..069a03f717d304e1c9e2b1e0387181b612118661 100644 (file)
@@ -644,9 +644,15 @@ struct vortex_private {
        u16 deferred;                                           /* Resend these interrupts when we
                                                                                 * bale from the ISR */
        u16 io_size;                                            /* Size of PCI region (for release_region) */
-       spinlock_t lock;                                        /* Serialise access to device & its vortex_private */
-       struct mii_if_info mii;                         /* MII lib hooks/info */
-       int window;                                     /* Register window */
+
+       /* Serialises access to hardware other than MII and variables below.
+        * The lock hierarchy is rtnl_lock > lock > mii_lock > window_lock. */
+       spinlock_t lock;
+
+       spinlock_t mii_lock;            /* Serialises access to MII */
+       struct mii_if_info mii;         /* MII lib hooks/info */
+       spinlock_t window_lock;         /* Serialises access to windowed regs */
+       int window;                     /* Register window */
 };
 
 static void window_set(struct vortex_private *vp, int window)
@@ -661,15 +667,23 @@ static void window_set(struct vortex_private *vp, int window)
 static u ## size                                                       \
 window_read ## size(struct vortex_private *vp, int window, int addr)   \
 {                                                                      \
+       unsigned long flags;                                            \
+       u ## size ret;                                                  \
+       spin_lock_irqsave(&vp->window_lock, flags);                     \
        window_set(vp, window);                                         \
-       return ioread ## size(vp->ioaddr + addr);                       \
+       ret = ioread ## size(vp->ioaddr + addr);                        \
+       spin_unlock_irqrestore(&vp->window_lock, flags);                \
+       return ret;                                                     \
 }                                                                      \
 static void                                                            \
 window_write ## size(struct vortex_private *vp, u ## size value,       \
                     int window, int addr)                              \
 {                                                                      \
+       unsigned long flags;                                            \
+       spin_lock_irqsave(&vp->window_lock, flags);                     \
        window_set(vp, window);                                         \
        iowrite ## size(value, vp->ioaddr + addr);                      \
+       spin_unlock_irqrestore(&vp->window_lock, flags);                \
 }
 DEFINE_WINDOW_IO(8)
 DEFINE_WINDOW_IO(16)
@@ -1181,6 +1195,8 @@ static int __devinit vortex_probe1(struct device *gendev,
        }
 
        spin_lock_init(&vp->lock);
+       spin_lock_init(&vp->mii_lock);
+       spin_lock_init(&vp->window_lock);
        vp->gendev = gendev;
        vp->mii.dev = dev;
        vp->mii.mdio_read = mdio_read;
@@ -1784,7 +1800,6 @@ vortex_timer(unsigned long data)
                pr_debug("dev->watchdog_timeo=%d\n", dev->watchdog_timeo);
        }
 
-       disable_irq_lockdep(dev->irq);
        media_status = window_read16(vp, 4, Wn4_Media);
        switch (dev->if_port) {
        case XCVR_10baseT:  case XCVR_100baseTx:  case XCVR_100baseFx:
@@ -1805,10 +1820,7 @@ vortex_timer(unsigned long data)
        case XCVR_MII: case XCVR_NWAY:
                {
                        ok = 1;
-                       /* Interrupts are already disabled */
-                       spin_lock(&vp->lock);
                        vortex_check_media(dev, 0);
-                       spin_unlock(&vp->lock);
                }
                break;
          default:                                      /* Other media types handled by Tx timeouts. */
@@ -1827,6 +1839,8 @@ vortex_timer(unsigned long data)
        if (!ok) {
                unsigned int config;
 
+               spin_lock_irq(&vp->lock);
+
                do {
                        dev->if_port = media_tbl[dev->if_port].next;
                } while ( ! (vp->available_media & media_tbl[dev->if_port].mask));
@@ -1855,6 +1869,8 @@ vortex_timer(unsigned long data)
                if (vortex_debug > 1)
                        pr_debug("wrote 0x%08x to Wn3_Config\n", config);
                /* AKPM: FIXME: Should reset Rx & Tx here.  P60 of 3c90xc.pdf */
+
+               spin_unlock_irq(&vp->lock);
        }
 
 leave_media_alone:
@@ -1862,7 +1878,6 @@ leave_media_alone:
          pr_debug("%s: Media selection timer finished, %s.\n",
                         dev->name, media_tbl[dev->if_port].name);
 
-       enable_irq_lockdep(dev->irq);
        mod_timer(&vp->timer, RUN_AT(next_tick));
        if (vp->deferred)
                iowrite16(FakeIntr, ioaddr + EL3_CMD);
@@ -2051,9 +2066,11 @@ vortex_start_xmit(struct sk_buff *skb, struct net_device *dev)
                int len = (skb->len + 3) & ~3;
                vp->tx_skb_dma = pci_map_single(VORTEX_PCI(vp), skb->data, len,
                                                PCI_DMA_TODEVICE);
+               spin_lock_irq(&vp->window_lock);
                window_set(vp, 7);
                iowrite32(vp->tx_skb_dma, ioaddr + Wn7_MasterAddr);
                iowrite16(len, ioaddr + Wn7_MasterLen);
+               spin_unlock_irq(&vp->window_lock);
                vp->tx_skb = skb;
                iowrite16(StartDMADown, ioaddr + EL3_CMD);
                /* netif_wake_queue() will be called at the DMADone interrupt. */
@@ -2225,6 +2242,7 @@ vortex_interrupt(int irq, void *dev_id)
                pr_debug("%s: interrupt, status %4.4x, latency %d ticks.\n",
                           dev->name, status, ioread8(ioaddr + Timer));
 
+       spin_lock(&vp->window_lock);
        window_set(vp, 7);
 
        do {
@@ -2285,6 +2303,8 @@ vortex_interrupt(int irq, void *dev_id)
                iowrite16(AckIntr | IntReq | IntLatch, ioaddr + EL3_CMD);
        } while ((status = ioread16(ioaddr + EL3_STATUS)) & (IntLatch | RxComplete));
 
+       spin_unlock(&vp->window_lock);
+
        if (vortex_debug > 4)
                pr_debug("%s: exiting interrupt, status %4.4x.\n",
                           dev->name, status);
@@ -2806,37 +2826,22 @@ static void update_stats(void __iomem *ioaddr, struct net_device *dev)
 static int vortex_nway_reset(struct net_device *dev)
 {
        struct vortex_private *vp = netdev_priv(dev);
-       unsigned long flags;
-       int rc;
 
-       spin_lock_irqsave(&vp->lock, flags);
-       rc = mii_nway_restart(&vp->mii);
-       spin_unlock_irqrestore(&vp->lock, flags);
-       return rc;
+       return mii_nway_restart(&vp->mii);
 }
 
 static int vortex_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
 {
        struct vortex_private *vp = netdev_priv(dev);
-       unsigned long flags;
-       int rc;
 
-       spin_lock_irqsave(&vp->lock, flags);
-       rc = mii_ethtool_gset(&vp->mii, cmd);
-       spin_unlock_irqrestore(&vp->lock, flags);
-       return rc;
+       return mii_ethtool_gset(&vp->mii, cmd);
 }
 
 static int vortex_set_settings(struct net_device *dev, struct ethtool_cmd *cmd)
 {
        struct vortex_private *vp = netdev_priv(dev);
-       unsigned long flags;
-       int rc;
 
-       spin_lock_irqsave(&vp->lock, flags);
-       rc = mii_ethtool_sset(&vp->mii, cmd);
-       spin_unlock_irqrestore(&vp->lock, flags);
-       return rc;
+       return mii_ethtool_sset(&vp->mii, cmd);
 }
 
 static u32 vortex_get_msglevel(struct net_device *dev)
@@ -3059,6 +3064,8 @@ static int mdio_read(struct net_device *dev, int phy_id, int location)
        int read_cmd = (0xf6 << 10) | (phy_id << 5) | location;
        unsigned int retval = 0;
 
+       spin_lock_bh(&vp->mii_lock);
+
        if (mii_preamble_required)
                mdio_sync(vp, 32);
 
@@ -3082,6 +3089,9 @@ static int mdio_read(struct net_device *dev, int phy_id, int location)
                               4, Wn4_PhysicalMgmt);
                mdio_delay(vp);
        }
+
+       spin_unlock_bh(&vp->mii_lock);
+
        return retval & 0x20000 ? 0xffff : retval>>1 & 0xffff;
 }
 
@@ -3091,6 +3101,8 @@ static void mdio_write(struct net_device *dev, int phy_id, int location, int val
        int write_cmd = 0x50020000 | (phy_id << 23) | (location << 18) | value;
        int i;
 
+       spin_lock_bh(&vp->mii_lock);
+
        if (mii_preamble_required)
                mdio_sync(vp, 32);
 
@@ -3111,6 +3123,8 @@ static void mdio_write(struct net_device *dev, int phy_id, int location, int val
                               4, Wn4_PhysicalMgmt);
                mdio_delay(vp);
        }
+
+       spin_unlock_bh(&vp->mii_lock);
 }
 
 /* ACPI: Advanced Configuration and Power Interface. */