b43: Remove unnecessary MMIO accesses in the interrupt hotpath.

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@15160 3c298f89-4303-0410-b956-a3cf2f4a3e73

diff --git a/package/mac80211/patches/530-b43-optimize-hotpath-mmio.patch b/package/mac80211/patches/530-b43-optimize-hotpath-mmio.patch
new file mode 100644 (file)
index 0000000..3413731
--- /dev/null
+++ b/package/mac80211/patches/530-b43-optimize-hotpath-mmio.patch
@@ -0,0 +1,177 @@
+Index: compat-wireless-2009-03-31/drivers/net/wireless/b43/b43.h
+===================================================================
+--- compat-wireless-2009-03-31.orig/drivers/net/wireless/b43/b43.h     2009-04-08 20:27:37.000000000 +0200
++++ compat-wireless-2009-03-31/drivers/net/wireless/b43/b43.h  2009-04-08 20:28:14.000000000 +0200
+@@ -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: compat-wireless-2009-03-31/drivers/net/wireless/b43/main.c
+===================================================================
+--- compat-wireless-2009-03-31.orig/drivers/net/wireless/b43/main.c    2009-04-08 20:22:24.000000000 +0200
++++ compat-wireless-2009-03-31/drivers/net/wireless/b43/main.c 2009-04-08 20:41:43.000000000 +0200
+@@ -673,32 +673,6 @@ static void b43_short_slot_timing_disabl
+       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
+       /* 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
+       /* 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_wo
+       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
+       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
+       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
+       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
+           & 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(struc
+        * 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(struc
+ 
+       /* 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);
+@@ -3998,9 +3975,9 @@ static void setup_struct_wldev_for_init(
+       /* 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;
+