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Commit 44710bbc authored by Stefano Brivio's avatar Stefano Brivio Committed by John W. Linville
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b43legacy: Remove unnecessary MMIO in interrupt hotpath 



This removes unnecessary MMIO accesses in the interrupt hotpath. The
patch by Michael Buesch for b43 has been ported to b43legacy.

Signed-off-by: default avatarStefano Brivio <stefano.brivio@polimi.it>
Tested-by: default avatarLarry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 6b96f93e

drivers/net/wireless/b43legacy/b43legacy.h

+2 −2
Original line number Diff line number Diff line
@@ -694,8 +694,8 @@ struct b43legacy_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 b43legacy_noise_calculation noisecalc;

	/* if > 0 MAC is suspended. if == 0 MAC is enabled. */

drivers/net/wireless/b43legacy/main.c

+22 −56
Original line number Diff line number Diff line
@@ -583,35 +583,6 @@ static void b43legacy_short_slot_timing_disable(struct b43legacy_wldev *dev) 
	b43legacy_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 b43legacy_interrupt_enable(struct b43legacy_wldev *dev,

					     u32 mask)

{

	u32 old_mask;



	old_mask = b43legacy_read32(dev, B43legacy_MMIO_GEN_IRQ_MASK);

	b43legacy_write32(dev, B43legacy_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 b43legacy_interrupt_disable(struct b43legacy_wldev *dev,

					      u32 mask)

{

	u32 old_mask;



	old_mask = b43legacy_read32(dev, B43legacy_MMIO_GEN_IRQ_MASK);

	b43legacy_write32(dev, B43legacy_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.
@@ -1200,7 +1171,7 @@ static void handle_irq_beacon(struct b43legacy_wldev *dev) 
	/* This is the bottom half of the asynchronous beacon update. */



	/* Ignore interrupt in the future. */

	dev->irq_savedstate &= ~B43legacy_IRQ_BEACON;

	dev->irq_mask &= ~B43legacy_IRQ_BEACON;



	cmd = b43legacy_read32(dev, B43legacy_MMIO_MACCMD);

	beacon0_valid = (cmd & B43legacy_MACCMD_BEACON0_VALID);
@@ -1209,7 +1180,7 @@ static void handle_irq_beacon(struct b43legacy_wldev *dev) 
	/* Schedule interrupt manually, if busy. */

	if (beacon0_valid && beacon1_valid) {

		b43legacy_write32(dev, B43legacy_MMIO_GEN_IRQ_REASON, B43legacy_IRQ_BEACON);

		dev->irq_savedstate |= B43legacy_IRQ_BEACON;

		dev->irq_mask |= B43legacy_IRQ_BEACON;

		return;

	}
@@ -1247,12 +1218,11 @@ static void b43legacy_beacon_update_trigger_work(struct work_struct *work) 
	dev = wl->current_dev;

	if (likely(dev && (b43legacy_status(dev) >= B43legacy_STAT_INITIALIZED))) {

		spin_lock_irq(&wl->irq_lock);

		/* update beacon right away or defer to irq */

		dev->irq_savedstate = b43legacy_read32(dev, B43legacy_MMIO_GEN_IRQ_MASK);

		/* Update beacon right away or defer to IRQ. */

		handle_irq_beacon(dev);

		/* The handler might have updated the IRQ mask. */

		b43legacy_write32(dev, B43legacy_MMIO_GEN_IRQ_MASK,

			    dev->irq_savedstate);

				  dev->irq_mask);

		mmiowb();

		spin_unlock_irq(&wl->irq_lock);

	}
@@ -1398,7 +1368,7 @@ static void b43legacy_interrupt_tasklet(struct b43legacy_wldev *dev) 
	if (reason & B43legacy_IRQ_TX_OK)

		handle_irq_transmit_status(dev);



	b43legacy_interrupt_enable(dev, dev->irq_savedstate);

	b43legacy_write32(dev, B43legacy_MMIO_GEN_IRQ_MASK, dev->irq_mask);

	mmiowb();

	spin_unlock_irqrestore(&dev->wl->irq_lock, flags);

}
@@ -1450,18 +1420,18 @@ static irqreturn_t b43legacy_interrupt_handler(int irq, void *dev_id) 
	struct b43legacy_wldev *dev = dev_id;

	u32 reason;



	if (!dev)

		return IRQ_NONE;

	B43legacy_WARN_ON(!dev);



	spin_lock(&dev->wl->irq_lock);



	if (b43legacy_status(dev) < B43legacy_STAT_STARTED)

	if (unlikely(b43legacy_status(dev) < B43legacy_STAT_STARTED))

		/* This can only happen on shared IRQ lines. */

		goto out;

	reason = b43legacy_read32(dev, B43legacy_MMIO_GEN_IRQ_REASON);

	if (reason == 0xffffffff) /* shared IRQ */

		goto out;

	ret = IRQ_HANDLED;

	reason &= b43legacy_read32(dev, B43legacy_MMIO_GEN_IRQ_MASK);

	reason &= dev->irq_mask;

	if (!reason)

		goto out;
@@ -1485,10 +1455,9 @@ static irqreturn_t b43legacy_interrupt_handler(int irq, void *dev_id) 
					      & 0x0000DC00;



	b43legacy_interrupt_ack(dev, reason);

	/* disable all IRQs. They are enabled again in the bottom half. */

	dev->irq_savedstate = b43legacy_interrupt_disable(dev,

							  B43legacy_IRQ_ALL);

	/* save the reason code and call our bottom half. */

	/* Disable all IRQs. They are enabled again in the bottom half. */

	b43legacy_write32(dev, B43legacy_MMIO_GEN_IRQ_MASK, 0);

	/* Save the reason code and call our bottom half. */

	dev->irq_reason = reason;

	tasklet_schedule(&dev->isr_tasklet);

out:
@@ -1948,7 +1917,8 @@ void b43legacy_mac_enable(struct b43legacy_wldev *dev) 


		/* Re-enable IRQs. */

		spin_lock_irq(&dev->wl->irq_lock);

		b43legacy_interrupt_enable(dev, dev->irq_savedstate);

		b43legacy_write32(dev, B43legacy_MMIO_GEN_IRQ_MASK,

				  dev->irq_mask);

		spin_unlock_irq(&dev->wl->irq_lock);

	}

}
@@ -1967,10 +1937,9 @@ void b43legacy_mac_suspend(struct b43legacy_wldev *dev) 
		/* Mask IRQs before suspending MAC. Otherwise

		 * the MAC stays busy and won't suspend. */

		spin_lock_irq(&dev->wl->irq_lock);

		tmp = b43legacy_interrupt_disable(dev, B43legacy_IRQ_ALL);

		b43legacy_write32(dev, B43legacy_MMIO_GEN_IRQ_MASK, 0);

		spin_unlock_irq(&dev->wl->irq_lock);

		b43legacy_synchronize_irq(dev);

		dev->irq_savedstate = tmp;



		b43legacy_power_saving_ctl_bits(dev, -1, 1);

		b43legacy_write32(dev, B43legacy_MMIO_MACCTL,
@@ -2659,7 +2628,6 @@ static int b43legacy_op_dev_config(struct ieee80211_hw *hw, 
	int antenna_tx;

	int antenna_rx;

	int err = 0;

	u32 savedirqs;



	antenna_tx = B43legacy_ANTENNA_DEFAULT;

	antenna_rx = B43legacy_ANTENNA_DEFAULT;
@@ -2699,7 +2667,7 @@ static int b43legacy_op_dev_config(struct ieee80211_hw *hw, 
		spin_unlock_irqrestore(&wl->irq_lock, flags);

		goto out_unlock_mutex;

	}

	savedirqs = b43legacy_interrupt_disable(dev, B43legacy_IRQ_ALL);

	b43legacy_write32(dev, B43legacy_MMIO_GEN_IRQ_MASK, 0);

	spin_unlock_irqrestore(&wl->irq_lock, flags);

	b43legacy_synchronize_irq(dev);
@@ -2738,7 +2706,7 @@ static int b43legacy_op_dev_config(struct ieee80211_hw *hw, 
	}



	spin_lock_irqsave(&wl->irq_lock, flags);

	b43legacy_interrupt_enable(dev, savedirqs);

	b43legacy_write32(dev, B43legacy_MMIO_GEN_IRQ_MASK, dev->irq_mask);

	mmiowb();

	spin_unlock_irqrestore(&wl->irq_lock, flags);

out_unlock_mutex:
@@ -2801,7 +2769,6 @@ static void b43legacy_op_bss_info_changed(struct ieee80211_hw *hw, 
	struct b43legacy_wldev *dev;

	struct b43legacy_phy *phy;

	unsigned long flags;

	u32 savedirqs;



	mutex_lock(&wl->mutex);

	B43legacy_WARN_ON(wl->vif != vif);
@@ -2817,7 +2784,7 @@ static void b43legacy_op_bss_info_changed(struct ieee80211_hw *hw, 
		spin_unlock_irqrestore(&wl->irq_lock, flags);

		goto out_unlock_mutex;

	}

	savedirqs = b43legacy_interrupt_disable(dev, B43legacy_IRQ_ALL);

	b43legacy_write32(dev, B43legacy_MMIO_GEN_IRQ_MASK, 0);



	if (changed & BSS_CHANGED_BSSID) {

		spin_unlock_irqrestore(&wl->irq_lock, flags);
@@ -2862,7 +2829,7 @@ static void b43legacy_op_bss_info_changed(struct ieee80211_hw *hw, 
	b43legacy_mac_enable(dev);



	spin_lock_irqsave(&wl->irq_lock, flags);

	b43legacy_interrupt_enable(dev, savedirqs);

	b43legacy_write32(dev, B43legacy_MMIO_GEN_IRQ_MASK, dev->irq_mask);

	/* XXX: why? */

	mmiowb();

	spin_unlock_irqrestore(&wl->irq_lock, flags);
@@ -2922,8 +2889,7 @@ static void b43legacy_wireless_core_stop(struct b43legacy_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 = b43legacy_interrupt_disable(dev,

							  B43legacy_IRQ_ALL);

	b43legacy_write32(dev, B43legacy_MMIO_GEN_IRQ_MASK, 0);

	b43legacy_read32(dev, B43legacy_MMIO_GEN_IRQ_MASK); /* flush */

	spin_unlock_irqrestore(&wl->irq_lock, flags);

	b43legacy_synchronize_irq(dev);
@@ -2963,7 +2929,7 @@ static int b43legacy_wireless_core_start(struct b43legacy_wldev *dev) 


	/* Start data flow (TX/RX) */

	b43legacy_mac_enable(dev);

	b43legacy_interrupt_enable(dev, dev->irq_savedstate);

	b43legacy_write32(dev, B43legacy_MMIO_GEN_IRQ_MASK, dev->irq_mask);



	/* Start maintenance work */

	b43legacy_periodic_tasks_setup(dev);
@@ -3126,7 +3092,7 @@ static void setup_struct_wldev_for_init(struct b43legacy_wldev *dev) 
	/* IRQ related flags */

	dev->irq_reason = 0;

	memset(dev->dma_reason, 0, sizeof(dev->dma_reason));

	dev->irq_savedstate = B43legacy_IRQ_MASKTEMPLATE;

	dev->irq_mask = B43legacy_IRQ_MASKTEMPLATE;



	dev->mac_suspended = 1;

drivers/net/wireless/b43legacy/pio.c

+1 −1
Original line number Diff line number Diff line
@@ -443,7 +443,7 @@ int b43legacy_pio_init(struct b43legacy_wldev *dev) 
	pio->queue3 = queue;



	if (dev->dev->id.revision < 3)

		dev->irq_savedstate |= B43legacy_IRQ_PIO_WORKAROUND;

		dev->irq_mask |= B43legacy_IRQ_PIO_WORKAROUND;



	b43legacydbg(dev->wl, "PIO initialized\n");

	err = 0;