b43: Remove unnecessary MMIO in interrupt hotpath
Michael Buesch [Wed, 8 Apr 2009 19:26:27 +0000 (21:26 +0200)]
This removes unnecessary MMIO accesses in the interrupt hotpath.

Signed-off-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/b43/b43.h
drivers/net/wireless/b43/main.c

index cc1db7e..4e8ad84 100644 (file)
@@ -778,8 +778,8 @@ struct b43_wldev {
        /* Reason code of the last interrupt. */
        u32 irq_reason;
        u32 dma_reason[6];
-       /* saved irq enable/disable state bitfield. */
-       u32 irq_savedstate;
+       /* The currently active generic-interrupt mask. */
+       u32 irq_mask;
        /* Link Quality calculation context. */
        struct b43_noise_calculation noisecalc;
        /* if > 0 MAC is suspended. if == 0 MAC is enabled. */
index 09e0c60..a97c6ff 100644 (file)
@@ -673,32 +673,6 @@ static void b43_short_slot_timing_disable(struct b43_wldev *dev)
        b43_set_slot_time(dev, 20);
 }
 
-/* Enable a Generic IRQ. "mask" is the mask of which IRQs to enable.
- * Returns the _previously_ enabled IRQ mask.
- */
-static inline u32 b43_interrupt_enable(struct b43_wldev *dev, u32 mask)
-{
-       u32 old_mask;
-
-       old_mask = b43_read32(dev, B43_MMIO_GEN_IRQ_MASK);
-       b43_write32(dev, B43_MMIO_GEN_IRQ_MASK, old_mask | mask);
-
-       return old_mask;
-}
-
-/* Disable a Generic IRQ. "mask" is the mask of which IRQs to disable.
- * Returns the _previously_ enabled IRQ mask.
- */
-static inline u32 b43_interrupt_disable(struct b43_wldev *dev, u32 mask)
-{
-       u32 old_mask;
-
-       old_mask = b43_read32(dev, B43_MMIO_GEN_IRQ_MASK);
-       b43_write32(dev, B43_MMIO_GEN_IRQ_MASK, old_mask & ~mask);
-
-       return old_mask;
-}
-
 /* Synchronize IRQ top- and bottom-half.
  * IRQs must be masked before calling this.
  * This must not be called with the irq_lock held.
@@ -1593,7 +1567,7 @@ static void handle_irq_beacon(struct b43_wldev *dev)
        /* This is the bottom half of the asynchronous beacon update. */
 
        /* Ignore interrupt in the future. */
-       dev->irq_savedstate &= ~B43_IRQ_BEACON;
+       dev->irq_mask &= ~B43_IRQ_BEACON;
 
        cmd = b43_read32(dev, B43_MMIO_MACCMD);
        beacon0_valid = (cmd & B43_MACCMD_BEACON0_VALID);
@@ -1602,7 +1576,7 @@ static void handle_irq_beacon(struct b43_wldev *dev)
        /* Schedule interrupt manually, if busy. */
        if (beacon0_valid && beacon1_valid) {
                b43_write32(dev, B43_MMIO_GEN_IRQ_REASON, B43_IRQ_BEACON);
-               dev->irq_savedstate |= B43_IRQ_BEACON;
+               dev->irq_mask |= B43_IRQ_BEACON;
                return;
        }
 
@@ -1641,11 +1615,9 @@ static void b43_beacon_update_trigger_work(struct work_struct *work)
        if (likely(dev && (b43_status(dev) >= B43_STAT_INITIALIZED))) {
                spin_lock_irq(&wl->irq_lock);
                /* update beacon right away or defer to irq */
-               dev->irq_savedstate = b43_read32(dev, B43_MMIO_GEN_IRQ_MASK);
                handle_irq_beacon(dev);
                /* The handler might have updated the IRQ mask. */
-               b43_write32(dev, B43_MMIO_GEN_IRQ_MASK,
-                           dev->irq_savedstate);
+               b43_write32(dev, B43_MMIO_GEN_IRQ_MASK, dev->irq_mask);
                mmiowb();
                spin_unlock_irq(&wl->irq_lock);
        }
@@ -1879,7 +1851,7 @@ static void b43_interrupt_tasklet(struct b43_wldev *dev)
        if (reason & B43_IRQ_TX_OK)
                handle_irq_transmit_status(dev);
 
-       b43_interrupt_enable(dev, dev->irq_savedstate);
+       b43_write32(dev, B43_MMIO_GEN_IRQ_MASK, dev->irq_mask);
        mmiowb();
        spin_unlock_irqrestore(&dev->wl->irq_lock, flags);
 }
@@ -1893,7 +1865,9 @@ static void b43_interrupt_ack(struct b43_wldev *dev, u32 reason)
        b43_write32(dev, B43_MMIO_DMA2_REASON, dev->dma_reason[2]);
        b43_write32(dev, B43_MMIO_DMA3_REASON, dev->dma_reason[3]);
        b43_write32(dev, B43_MMIO_DMA4_REASON, dev->dma_reason[4]);
+/* Unused ring
        b43_write32(dev, B43_MMIO_DMA5_REASON, dev->dma_reason[5]);
+*/
 }
 
 /* Interrupt handler top-half */
@@ -1903,18 +1877,19 @@ static irqreturn_t b43_interrupt_handler(int irq, void *dev_id)
        struct b43_wldev *dev = dev_id;
        u32 reason;
 
-       if (!dev)
-               return IRQ_NONE;
+       B43_WARN_ON(!dev);
 
        spin_lock(&dev->wl->irq_lock);
 
-       if (b43_status(dev) < B43_STAT_STARTED)
+       if (unlikely(b43_status(dev) < B43_STAT_STARTED)) {
+               /* This can only happen on shared IRQ lines. */
                goto out;
+       }
        reason = b43_read32(dev, B43_MMIO_GEN_IRQ_REASON);
        if (reason == 0xffffffff)       /* shared IRQ */
                goto out;
        ret = IRQ_HANDLED;
-       reason &= b43_read32(dev, B43_MMIO_GEN_IRQ_MASK);
+       reason &= dev->irq_mask;
        if (!reason)
                goto out;
 
@@ -1928,16 +1903,18 @@ static irqreturn_t b43_interrupt_handler(int irq, void *dev_id)
            & 0x0001DC00;
        dev->dma_reason[4] = b43_read32(dev, B43_MMIO_DMA4_REASON)
            & 0x0000DC00;
+/* Unused ring
        dev->dma_reason[5] = b43_read32(dev, B43_MMIO_DMA5_REASON)
            & 0x0000DC00;
+*/
 
        b43_interrupt_ack(dev, reason);
        /* disable all IRQs. They are enabled again in the bottom half. */
-       dev->irq_savedstate = b43_interrupt_disable(dev, B43_IRQ_ALL);
+       b43_write32(dev, B43_MMIO_GEN_IRQ_MASK, 0);
        /* save the reason code and call our bottom half. */
        dev->irq_reason = reason;
        tasklet_schedule(&dev->isr_tasklet);
-      out:
+out:
        mmiowb();
        spin_unlock(&dev->wl->irq_lock);
 
@@ -3799,7 +3776,7 @@ static void b43_wireless_core_stop(struct b43_wldev *dev)
         * setting the status to INITIALIZED, as the interrupt handler
         * won't care about IRQs then. */
        spin_lock_irqsave(&wl->irq_lock, flags);
-       dev->irq_savedstate = b43_interrupt_disable(dev, B43_IRQ_ALL);
+       b43_write32(dev, B43_MMIO_GEN_IRQ_MASK, 0);
        b43_read32(dev, B43_MMIO_GEN_IRQ_MASK); /* flush */
        spin_unlock_irqrestore(&wl->irq_lock, flags);
        b43_synchronize_irq(dev);
@@ -3840,7 +3817,7 @@ static int b43_wireless_core_start(struct b43_wldev *dev)
 
        /* Start data flow (TX/RX). */
        b43_mac_enable(dev);
-       b43_interrupt_enable(dev, dev->irq_savedstate);
+       b43_write32(dev, B43_MMIO_GEN_IRQ_MASK, dev->irq_mask);
 
        /* Start maintainance work */
        b43_periodic_tasks_setup(dev);
@@ -4003,9 +3980,9 @@ static void setup_struct_wldev_for_init(struct b43_wldev *dev)
        /* IRQ related flags */
        dev->irq_reason = 0;
        memset(dev->dma_reason, 0, sizeof(dev->dma_reason));
-       dev->irq_savedstate = B43_IRQ_MASKTEMPLATE;
+       dev->irq_mask = B43_IRQ_MASKTEMPLATE;
        if (b43_modparam_verbose < B43_VERBOSITY_DEBUG)
-               dev->irq_savedstate &= ~B43_IRQ_PHY_TXERR;
+               dev->irq_mask &= ~B43_IRQ_PHY_TXERR;
 
        dev->mac_suspended = 1;