b43: Use a threaded IRQ handler

Use a threaded IRQ handler to allow locking the mutex and
sleeping while executing an interrupt.
This removes usage of the irq_lock spinlock, but introduces
a new hardirq_lock, which is _only_ used for the PCI/SSB lowlevel
hard-irq handler. Sleeping busses (SDIO) will use mutex instead.

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

11 files changed, 204 insertions, 221 deletions

diff --git a/drivers/net/wireless/b43/b43.h b/drivers/net/wireless/b43/b43.h
index a1b3b731935b..d63af926d058 100644
--- a/drivers/net/wireless/b43/b43.h
+++ b/drivers/net/wireless/b43/b43.h
@@ -616,6 +616,12 @@ struct b43_wl {
         /* Pointer to the ieee80211 hardware data structure */
         struct ieee80211_hw *hw;
 
+        /* Global driver mutex. Every operation must run with this mutex locked. */
+        struct mutex mutex;
+        /* Hard-IRQ spinlock. This lock protects things used in the hard-IRQ
+         * handler, only. This basically is just the IRQ mask register. */
+        spinlock_t hardirq_lock;
+
         /* The number of queues that were registered with the mac80211 subsystem
          * initially. This is a backup copy of hw->queues in case hw->queues has
          * to be dynamically lowered at runtime (Firmware does not support QoS).
@@ -623,8 +629,6 @@ struct b43_wl {
          * from the mac80211 subsystem. */
         u16 mac80211_initially_registered_queues;
 
-        struct mutex mutex;
-        spinlock_t irq_lock;
         /* R/W lock for data transmission.
          * Transmissions on 2+ queues can run concurrently, but somebody else
          * might sync with TX by write_lock_irqsave()'ing. */
@@ -665,8 +669,7 @@ struct b43_wl {
         bool radiotap_enabled;
         bool radio_enabled;
 
-        /* The beacon we are currently using (AP or IBSS mode).
-         * This beacon stuff is protected by the irq_lock. */
+        /* The beacon we are currently using (AP or IBSS mode). */
         struct sk_buff *current_beacon;
         bool beacon0_uploaded;
         bool beacon1_uploaded;
@@ -754,14 +757,6 @@ enum {
                 smp_wmb();                                      \
                                         } while (0)
 
-/* XXX---   HOW LOCKING WORKS IN B43   ---XXX
- *
- * You should always acquire both, wl->mutex and wl->irq_lock unless:
- * - You don't need to acquire wl->irq_lock, if the interface is stopped.
- * - You don't need to acquire wl->mutex in the IRQ handler, IRQ tasklet
- *   and packet TX path (and _ONLY_ there.)
- */
-
 /* Data structure for one wireless device (802.11 core) */
 struct b43_wldev {
         struct ssb_device *dev;
@@ -807,14 +802,12 @@ struct b43_wldev {
         u32 dma_reason[6];
         /* 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. */
         int mac_suspended;
 
-        /* Interrupt Service Routine tasklet (bottom-half) */
-        struct tasklet_struct isr_tasklet;
-
         /* Periodic tasks */
         struct delayed_work periodic_work;
         unsigned int periodic_state;
diff --git a/drivers/net/wireless/b43/debugfs.c b/drivers/net/wireless/b43/debugfs.c
index 45e3d6af69f5..bf23a3a863fa 100644
--- a/drivers/net/wireless/b43/debugfs.c
+++ b/drivers/net/wireless/b43/debugfs.c
@@ -46,8 +46,6 @@ struct b43_debugfs_fops {
         struct file_operations fops;
         /* Offset of struct b43_dfs_file in struct b43_dfsentry */
         size_t file_struct_offset;
-        /* Take wl->irq_lock before calling read/write? */
-        bool take_irqlock;
 };
 
 static inline
@@ -372,14 +370,12 @@ static ssize_t txstat_read_file(struct b43_wldev *dev,
 {
         struct b43_txstatus_log *log = &dev->dfsentry->txstatlog;
         ssize_t count = 0;
-        unsigned long flags;
         int i, idx;
         struct b43_txstatus *stat;
 
-        spin_lock_irqsave(&log->lock, flags);
         if (log->end < 0) {
                 fappend("Nothing transmitted, yet\n");
-                goto out_unlock;
+                goto out;
         }
         fappend("b43 TX status reports:\n\n"
                 "index | cookie | seq | phy_stat | frame_count | "
@@ -409,13 +405,11 @@ static ssize_t txstat_read_file(struct b43_wldev *dev,
                         break;
                 i++;
         }
-out_unlock:
-        spin_unlock_irqrestore(&log->lock, flags);
+out:
 
         return count;
 }
 
-/* wl->irq_lock is locked */
 static int restart_write_file(struct b43_wldev *dev,
                               const char *buf, size_t count)
 {
@@ -556,12 +550,7 @@ static ssize_t b43_debugfs_read(struct file *file, char __user *userbuf,
                         goto out_unlock;
                 }
                 memset(buf, 0, bufsize);
-                if (dfops->take_irqlock) {
-                        spin_lock_irq(&dev->wl->irq_lock);
-                        ret = dfops->read(dev, buf, bufsize);
-                        spin_unlock_irq(&dev->wl->irq_lock);
-                } else
-                        ret = dfops->read(dev, buf, bufsize);
+                ret = dfops->read(dev, buf, bufsize);
                 if (ret <= 0) {
                         free_pages((unsigned long)buf, buforder);
                         err = ret;
@@ -623,12 +612,7 @@ static ssize_t b43_debugfs_write(struct file *file,
                 err = -EFAULT;
                 goto out_freepage;
         }
-        if (dfops->take_irqlock) {
-                spin_lock_irq(&dev->wl->irq_lock);
-                err = dfops->write(dev, buf, count);
-                spin_unlock_irq(&dev->wl->irq_lock);
-        } else
-                err = dfops->write(dev, buf, count);
+        err = dfops->write(dev, buf, count);
         if (err)
                 goto out_freepage;
 
@@ -641,7 +625,7 @@ out_unlock:
 }
 
 
-#define B43_DEBUGFS_FOPS(name, _read, _write, _take_irqlock)    \
+#define B43_DEBUGFS_FOPS(name, _read, _write)                   \
         static struct b43_debugfs_fops fops_##name = {          \
                 .read   = _read,                                \
                 .write  = _write,                               \
@@ -652,20 +636,19 @@ out_unlock:
                 },                                              \
                 .file_struct_offset = offsetof(struct b43_dfsentry, \
                                                file_##name),    \
-                .take_irqlock   = _take_irqlock,                \
         }
 
-B43_DEBUGFS_FOPS(shm16read, shm16read__read_file, shm16read__write_file, 1);
-B43_DEBUGFS_FOPS(shm16write, NULL, shm16write__write_file, 1);
-B43_DEBUGFS_FOPS(shm32read, shm32read__read_file, shm32read__write_file, 1);
-B43_DEBUGFS_FOPS(shm32write, NULL, shm32write__write_file, 1);
-B43_DEBUGFS_FOPS(mmio16read, mmio16read__read_file, mmio16read__write_file, 1);
-B43_DEBUGFS_FOPS(mmio16write, NULL, mmio16write__write_file, 1);
-B43_DEBUGFS_FOPS(mmio32read, mmio32read__read_file, mmio32read__write_file, 1);
-B43_DEBUGFS_FOPS(mmio32write, NULL, mmio32write__write_file, 1);
-B43_DEBUGFS_FOPS(txstat, txstat_read_file, NULL, 0);
-B43_DEBUGFS_FOPS(restart, NULL, restart_write_file, 1);
-B43_DEBUGFS_FOPS(loctls, loctls_read_file, NULL, 0);
+B43_DEBUGFS_FOPS(shm16read, shm16read__read_file, shm16read__write_file);
+B43_DEBUGFS_FOPS(shm16write, NULL, shm16write__write_file);
+B43_DEBUGFS_FOPS(shm32read, shm32read__read_file, shm32read__write_file);
+B43_DEBUGFS_FOPS(shm32write, NULL, shm32write__write_file);
+B43_DEBUGFS_FOPS(mmio16read, mmio16read__read_file, mmio16read__write_file);
+B43_DEBUGFS_FOPS(mmio16write, NULL, mmio16write__write_file);
+B43_DEBUGFS_FOPS(mmio32read, mmio32read__read_file, mmio32read__write_file);
+B43_DEBUGFS_FOPS(mmio32write, NULL, mmio32write__write_file);
+B43_DEBUGFS_FOPS(txstat, txstat_read_file, NULL);
+B43_DEBUGFS_FOPS(restart, NULL, restart_write_file);
+B43_DEBUGFS_FOPS(loctls, loctls_read_file, NULL);
 
 
 bool b43_debug(struct b43_wldev *dev, enum b43_dyndbg feature)
@@ -738,7 +721,6 @@ void b43_debugfs_add_device(struct b43_wldev *dev)
                 return;
         }
         log->end = -1;
-        spin_lock_init(&log->lock);
 
         dev->dfsentry = e;
 
@@ -822,7 +804,6 @@ void b43_debugfs_remove_device(struct b43_wldev *dev)
         kfree(e);
 }
 
-/* Called with IRQs disabled. */
 void b43_debugfs_log_txstat(struct b43_wldev *dev,
                             const struct b43_txstatus *status)
 {
@@ -834,14 +815,12 @@ void b43_debugfs_log_txstat(struct b43_wldev *dev,
         if (!e)
                 return;
         log = &e->txstatlog;
-        spin_lock(&log->lock); /* IRQs are already disabled. */
         i = log->end + 1;
         if (i == B43_NR_LOGGED_TXSTATUS)
                 i = 0;
         log->end = i;
         cur = &(log->log[i]);
         memcpy(cur, status, sizeof(*cur));
-        spin_unlock(&log->lock);
 }
 
 void b43_debugfs_init(void)
diff --git a/drivers/net/wireless/b43/debugfs.h b/drivers/net/wireless/b43/debugfs.h
index b9d4de4a979c..e47b4b488b04 100644
--- a/drivers/net/wireless/b43/debugfs.h
+++ b/drivers/net/wireless/b43/debugfs.h
@@ -23,9 +23,10 @@ struct dentry;
 #define B43_NR_LOGGED_TXSTATUS  100
 
 struct b43_txstatus_log {
+        /* This structure is protected by wl->mutex */
+
         struct b43_txstatus *log;
         int end;
-        spinlock_t lock;
 };
 
 struct b43_dfs_file {
diff --git a/drivers/net/wireless/b43/dma.c b/drivers/net/wireless/b43/dma.c
index 289aaf6dfe79..25ced8bdec8f 100644
--- a/drivers/net/wireless/b43/dma.c
+++ b/drivers/net/wireless/b43/dma.c
@@ -1387,7 +1387,6 @@ out_unlock:
         return err;
 }
 
-/* Called with IRQs disabled. */
 void b43_dma_handle_txstatus(struct b43_wldev *dev,
                              const struct b43_txstatus *status)
 {
@@ -1402,7 +1401,7 @@ void b43_dma_handle_txstatus(struct b43_wldev *dev,
         if (unlikely(!ring))
                 return;
 
-        spin_lock(&ring->lock); /* IRQs are already disabled. */
+        spin_lock_irq(&ring->lock);
 
         B43_WARN_ON(!ring->tx);
         ops = ring->ops;
@@ -1463,7 +1462,7 @@ void b43_dma_handle_txstatus(struct b43_wldev *dev,
                 }
         }
 
-        spin_unlock(&ring->lock);
+        spin_unlock_irq(&ring->lock);
 }
 
 void b43_dma_get_tx_stats(struct b43_wldev *dev,
diff --git a/drivers/net/wireless/b43/main.c b/drivers/net/wireless/b43/main.c
index ae05f6671149..80b688441ffe 100644
--- a/drivers/net/wireless/b43/main.c
+++ b/drivers/net/wireless/b43/main.c
@@ -291,7 +291,7 @@ static struct ieee80211_supported_band b43_band_2GHz = {
 
 static void b43_wireless_core_exit(struct b43_wldev *dev);
 static int b43_wireless_core_init(struct b43_wldev *dev);
-static void b43_wireless_core_stop(struct b43_wldev *dev);
+static struct b43_wldev * b43_wireless_core_stop(struct b43_wldev *dev);
 static int b43_wireless_core_start(struct b43_wldev *dev);
 
 static int b43_ratelimit(struct b43_wl *wl)
@@ -685,16 +685,6 @@ static void b43_short_slot_timing_disable(struct b43_wldev *dev)
         b43_set_slot_time(dev, 20);
 }
 
-/* Synchronize IRQ top- and bottom-half.
- * IRQs must be masked before calling this.
- * This must not be called with the irq_lock held.
- */
-static void b43_synchronize_irq(struct b43_wldev *dev)
-{
-        synchronize_irq(dev->dev->irq);
-        tasklet_kill(&dev->isr_tasklet);
-}
-
 /* DummyTransmission function, as documented on
  * http://bcm-v4.sipsolutions.net/802.11/DummyTransmission
  */
@@ -720,8 +710,7 @@ void b43_dummy_transmission(struct b43_wldev *dev, bool ofdm, bool pa_on)
                 buffer[0] = 0x000B846E;
         }
 
-        spin_lock_irq(&wl->irq_lock);
-        write_lock(&wl->tx_lock);
+        write_lock_irq(&wl->tx_lock);
 
         for (i = 0; i < 5; i++)
                 b43_ram_write(dev, i * 4, buffer[i]);
@@ -779,8 +768,7 @@ void b43_dummy_transmission(struct b43_wldev *dev, bool ofdm, bool pa_on)
         if (phy->radio_ver == 0x2050 && phy->radio_rev <= 0x5)
                 b43_radio_write16(dev, 0x0051, 0x0037);
 
-        write_unlock(&wl->tx_lock);
-        spin_unlock_irq(&wl->irq_lock);
+        write_unlock_irq(&wl->tx_lock);
 }
 
 static void key_write(struct b43_wldev *dev,
@@ -1620,6 +1608,27 @@ static void handle_irq_beacon(struct b43_wldev *dev)
         }
 }
 
+static void b43_do_beacon_update_trigger_work(struct b43_wldev *dev)
+{
+        u32 old_irq_mask = dev->irq_mask;
+
+        /* update beacon right away or defer to irq */
+        handle_irq_beacon(dev);
+        if (old_irq_mask != dev->irq_mask) {
+                /* The handler updated the IRQ mask. */
+                B43_WARN_ON(!dev->irq_mask);
+                if (b43_read32(dev, B43_MMIO_GEN_IRQ_MASK)) {
+                        b43_write32(dev, B43_MMIO_GEN_IRQ_MASK, dev->irq_mask);
+                } else {
+                        /* Device interrupts are currently disabled. That means
+                         * we just ran the hardirq handler and scheduled the
+                         * IRQ thread. The thread will write the IRQ mask when
+                         * it finished, so there's nothing to do here. Writing
+                         * the mask _here_ would incorrectly re-enable IRQs. */
+                }
+        }
+}
+
 static void b43_beacon_update_trigger_work(struct work_struct *work)
 {
         struct b43_wl *wl = container_of(work, struct b43_wl,
@@ -1629,19 +1638,22 @@ static void b43_beacon_update_trigger_work(struct work_struct *work)
         mutex_lock(&wl->mutex);
         dev = wl->current_dev;
         if (likely(dev && (b43_status(dev) >= B43_STAT_INITIALIZED))) {
-                spin_lock_irq(&wl->irq_lock);
-                /* update beacon right away or defer to irq */
-                handle_irq_beacon(dev);
-                /* The handler might have updated the IRQ mask. */
-                b43_write32(dev, B43_MMIO_GEN_IRQ_MASK, dev->irq_mask);
-                mmiowb();
-                spin_unlock_irq(&wl->irq_lock);
+                if (0 /*FIXME dev->dev->bus->bustype == SSB_BUSTYPE_SDIO*/) {
+                        /* wl->mutex is enough. */
+                        b43_do_beacon_update_trigger_work(dev);
+                        mmiowb();
+                } else {
+                        spin_lock_irq(&wl->hardirq_lock);
+                        b43_do_beacon_update_trigger_work(dev);
+                        mmiowb();
+                        spin_unlock_irq(&wl->hardirq_lock);
+                }
         }
         mutex_unlock(&wl->mutex);
 }
 
 /* Asynchronously update the packet templates in template RAM.
- * Locking: Requires wl->irq_lock to be locked. */
+ * Locking: Requires wl->mutex to be locked. */
 static void b43_update_templates(struct b43_wl *wl)
 {
         struct sk_buff *beacon;
@@ -1778,18 +1790,15 @@ out:
                         B43_DEBUGIRQ_REASON_REG, B43_DEBUGIRQ_ACK);
 }
 
-/* Interrupt handler bottom-half */
-static void b43_interrupt_tasklet(struct b43_wldev *dev)
+static void b43_do_interrupt_thread(struct b43_wldev *dev)
 {
         u32 reason;
         u32 dma_reason[ARRAY_SIZE(dev->dma_reason)];
         u32 merged_dma_reason = 0;
         int i;
-        unsigned long flags;
-
-        spin_lock_irqsave(&dev->wl->irq_lock, flags);
 
-        B43_WARN_ON(b43_status(dev) != B43_STAT_STARTED);
+        if (unlikely(b43_status(dev) != B43_STAT_STARTED))
+                return;
 
         reason = dev->irq_reason;
         for (i = 0; i < ARRAY_SIZE(dma_reason); i++) {
@@ -1822,8 +1831,6 @@ static void b43_interrupt_tasklet(struct b43_wldev *dev)
                                dma_reason[2], dma_reason[3],
                                dma_reason[4], dma_reason[5]);
                         b43_controller_restart(dev, "DMA error");
-                        mmiowb();
-                        spin_unlock_irqrestore(&dev->wl->irq_lock, flags);
                         return;
                 }
                 if (merged_dma_reason & B43_DMAIRQ_NONFATALMASK) {
@@ -1867,47 +1874,36 @@ static void b43_interrupt_tasklet(struct b43_wldev *dev)
         if (reason & B43_IRQ_TX_OK)
                 handle_irq_transmit_status(dev);
 
+        /* Re-enable interrupts on the device by restoring the current interrupt mask. */
         b43_write32(dev, B43_MMIO_GEN_IRQ_MASK, dev->irq_mask);
-        mmiowb();
-        spin_unlock_irqrestore(&dev->wl->irq_lock, flags);
 }
 
-static void b43_interrupt_ack(struct b43_wldev *dev, u32 reason)
+/* Interrupt thread handler. Handles device interrupts in thread context. */
+static irqreturn_t b43_interrupt_thread_handler(int irq, void *dev_id)
 {
-        b43_write32(dev, B43_MMIO_GEN_IRQ_REASON, reason);
+        struct b43_wldev *dev = dev_id;
 
-        b43_write32(dev, B43_MMIO_DMA0_REASON, dev->dma_reason[0]);
-        b43_write32(dev, B43_MMIO_DMA1_REASON, dev->dma_reason[1]);
-        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]);
-*/
+        mutex_lock(&dev->wl->mutex);
+        b43_do_interrupt_thread(dev);
+        mmiowb();
+        mutex_unlock(&dev->wl->mutex);
+
+        return IRQ_HANDLED;
 }
 
-/* Interrupt handler top-half */
-static irqreturn_t b43_interrupt_handler(int irq, void *dev_id)
+static irqreturn_t b43_do_interrupt(struct b43_wldev *dev)
 {
-        irqreturn_t ret = IRQ_NONE;
-        struct b43_wldev *dev = dev_id;
         u32 reason;
 
-        B43_WARN_ON(!dev);
+        /* This code runs under wl->hardirq_lock, but _only_ on non-SDIO busses.
+         * On SDIO, this runs under wl->mutex. */
 
-        spin_lock(&dev->wl->irq_lock);
-
-        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;
+                return IRQ_NONE;
         reason &= dev->irq_mask;
         if (!reason)
-                goto out;
+                return IRQ_HANDLED;
 
         dev->dma_reason[0] = b43_read32(dev, B43_MMIO_DMA0_REASON)
             & 0x0001DC00;
@@ -1924,15 +1920,38 @@ static irqreturn_t b43_interrupt_handler(int irq, void *dev_id)
             & 0x0000DC00;
 */
 
-        b43_interrupt_ack(dev, reason);
-        /* disable all IRQs. They are enabled again in the bottom half. */
+        /* ACK the interrupt. */
+        b43_write32(dev, B43_MMIO_GEN_IRQ_REASON, reason);
+        b43_write32(dev, B43_MMIO_DMA0_REASON, dev->dma_reason[0]);
+        b43_write32(dev, B43_MMIO_DMA1_REASON, dev->dma_reason[1]);
+        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]);
+*/
+
+        /* Disable IRQs on the device. The IRQ thread handler will re-enable them. */
         b43_write32(dev, B43_MMIO_GEN_IRQ_MASK, 0);
-        /* save the reason code and call our bottom half. */
+        /* Save the reason bitmasks for the IRQ thread handler. */
         dev->irq_reason = reason;
-        tasklet_schedule(&dev->isr_tasklet);
-out:
+
+        return IRQ_WAKE_THREAD;
+}
+
+/* Interrupt handler top-half. This runs with interrupts disabled. */
+static irqreturn_t b43_interrupt_handler(int irq, void *dev_id)
+{
+        struct b43_wldev *dev = dev_id;
+        irqreturn_t ret;
+
+        if (unlikely(b43_status(dev) < B43_STAT_STARTED))
+                return IRQ_NONE;
+
+        spin_lock(&dev->wl->hardirq_lock);
+        ret = b43_do_interrupt(dev);
         mmiowb();
-        spin_unlock(&dev->wl->irq_lock);
+        spin_unlock(&dev->wl->hardirq_lock);
 
         return ret;
 }
@@ -3038,15 +3057,12 @@ static void b43_security_init(struct b43_wldev *dev)
 static int b43_rng_read(struct hwrng *rng, u32 *data)
 {
         struct b43_wl *wl = (struct b43_wl *)rng->priv;
-        unsigned long flags;
 
-        /* Don't take wl->mutex here, as it could deadlock with
-         * hwrng internal locking. It's not needed to take
-         * wl->mutex here, anyway. */
+        /* FIXME: We need to take wl->mutex here to make sure the device
+         * is not going away from under our ass. However it could deadlock
+         * with hwrng internal locking. */
 
-        spin_lock_irqsave(&wl->irq_lock, flags);
         *data = b43_read16(wl->current_dev, B43_MMIO_RNG);
-        spin_unlock_irqrestore(&wl->irq_lock, flags);
 
         return (sizeof(u16));
 }
@@ -3283,22 +3299,20 @@ static int b43_op_get_tx_stats(struct ieee80211_hw *hw,
                                struct ieee80211_tx_queue_stats *stats)
 {
         struct b43_wl *wl = hw_to_b43_wl(hw);
-        struct b43_wldev *dev = wl->current_dev;
-        unsigned long flags;
+        struct b43_wldev *dev;
         int err = -ENODEV;
 
-        if (!dev)
-                goto out;
-        spin_lock_irqsave(&wl->irq_lock, flags);
-        if (likely(b43_status(dev) >= B43_STAT_STARTED)) {
+        mutex_lock(&wl->mutex);
+        dev = wl->current_dev;
+        if (dev && b43_status(dev) >= B43_STAT_STARTED) {
                 if (b43_using_pio_transfers(dev))
                         b43_pio_get_tx_stats(dev, stats);
                 else
                         b43_dma_get_tx_stats(dev, stats);
                 err = 0;
         }
-        spin_unlock_irqrestore(&wl->irq_lock, flags);
-out:
+        mutex_unlock(&wl->mutex);
+
         return err;
 }
 
@@ -3306,11 +3320,10 @@ static int b43_op_get_stats(struct ieee80211_hw *hw,
                             struct ieee80211_low_level_stats *stats)
 {
         struct b43_wl *wl = hw_to_b43_wl(hw);
-        unsigned long flags;
 
-        spin_lock_irqsave(&wl->irq_lock, flags);
+        mutex_lock(&wl->mutex);
         memcpy(stats, &wl->ieee_stats, sizeof(*stats));
-        spin_unlock_irqrestore(&wl->irq_lock, flags);
+        mutex_unlock(&wl->mutex);
 
         return 0;
 }
@@ -3322,7 +3335,6 @@ static u64 b43_op_get_tsf(struct ieee80211_hw *hw)
         u64 tsf;
 
         mutex_lock(&wl->mutex);
-        spin_lock_irq(&wl->irq_lock);
         dev = wl->current_dev;
 
         if (dev && (b43_status(dev) >= B43_STAT_INITIALIZED))
@@ -3330,7 +3342,6 @@ static u64 b43_op_get_tsf(struct ieee80211_hw *hw)
         else
                 tsf = 0;
 
-        spin_unlock_irq(&wl->irq_lock);
         mutex_unlock(&wl->mutex);
 
         return tsf;
@@ -3342,13 +3353,11 @@ static void b43_op_set_tsf(struct ieee80211_hw *hw, u64 tsf)
         struct b43_wldev *dev;
 
         mutex_lock(&wl->mutex);
-        spin_lock_irq(&wl->irq_lock);
         dev = wl->current_dev;
 
         if (dev && (b43_status(dev) >= B43_STAT_INITIALIZED))
                 b43_tsf_write(dev, tsf);
 
-        spin_unlock_irq(&wl->irq_lock);
         mutex_unlock(&wl->mutex);
 }
 
@@ -3434,7 +3443,7 @@ static int b43_switch_band(struct b43_wl *wl, struct ieee80211_channel *chan)
         prev_status = b43_status(down_dev);
         /* Shutdown the currently running core. */
         if (prev_status >= B43_STAT_STARTED)
-                b43_wireless_core_stop(down_dev);
+                down_dev = b43_wireless_core_stop(down_dev);
         if (prev_status >= B43_STAT_INITIALIZED)
                 b43_wireless_core_exit(down_dev);
 
@@ -3498,7 +3507,6 @@ static int b43_op_config(struct ieee80211_hw *hw, u32 changed)
         struct b43_wldev *dev;
         struct b43_phy *phy;
         struct ieee80211_conf *conf = &hw->conf;
-        unsigned long flags;
         int antenna;
         int err = 0;
 
@@ -3529,13 +3537,11 @@ static int b43_op_config(struct ieee80211_hw *hw, u32 changed)
 
         /* Adjust the desired TX power level. */
         if (conf->power_level != 0) {
-                spin_lock_irqsave(&wl->irq_lock, flags);
                 if (conf->power_level != phy->desired_txpower) {
                         phy->desired_txpower = conf->power_level;
                         b43_phy_txpower_check(dev, B43_TXPWR_IGNORE_TIME |
                                                    B43_TXPWR_IGNORE_TSSI);
                 }
-                spin_unlock_irqrestore(&wl->irq_lock, flags);
         }
 
         /* Antennas for RX and management frame TX. */
@@ -3620,7 +3626,6 @@ static void b43_op_bss_info_changed(struct ieee80211_hw *hw,
 {
         struct b43_wl *wl = hw_to_b43_wl(hw);
         struct b43_wldev *dev;
-        unsigned long flags;
 
         mutex_lock(&wl->mutex);
 
@@ -3630,7 +3635,6 @@ static void b43_op_bss_info_changed(struct ieee80211_hw *hw,
 
         B43_WARN_ON(wl->vif != vif);
 
-        spin_lock_irqsave(&wl->irq_lock, flags);
         if (changed & BSS_CHANGED_BSSID) {
                 if (conf->bssid)
                         memcpy(wl->bssid, conf->bssid, ETH_ALEN);
@@ -3648,7 +3652,6 @@ static void b43_op_bss_info_changed(struct ieee80211_hw *hw,
                 if (changed & BSS_CHANGED_BSSID)
                         b43_write_mac_bssid_templates(dev);
         }
-        spin_unlock_irqrestore(&wl->irq_lock, flags);
 
         b43_mac_suspend(dev);
 
@@ -3683,18 +3686,15 @@ static int b43_op_set_key(struct ieee80211_hw *hw, enum set_key_cmd cmd,
         u8 algorithm;
         u8 index;
         int err;
+        unsigned long flags;
         static const u8 bcast_addr[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 
         if (modparam_nohwcrypt)
                 return -ENOSPC; /* User disabled HW-crypto */
 
         mutex_lock(&wl->mutex);
-        spin_lock_irq(&wl->irq_lock);
-        write_lock(&wl->tx_lock);
-        /* Why do we need all this locking here?
-         * mutex     -> Every config operation must take it.
-         * irq_lock  -> We modify the dev->key array, which is accessed
-         *              in the IRQ handlers.
+        write_lock_irqsave(&wl->tx_lock, flags);
+        /* mutex     -> Every config operation must take it.
          * tx_lock   -> We modify the dev->key array, which is accessed
          *              in the TX handler.
          */
@@ -3789,8 +3789,7 @@ out_unlock:
                        sta ? sta->addr : bcast_addr);
                 b43_dump_keymemory(dev);
         }
-        write_unlock(&wl->tx_lock);
-        spin_unlock_irq(&wl->irq_lock);
+        write_unlock_irqrestore(&wl->tx_lock, flags);
         mutex_unlock(&wl->mutex);
 
         return err;
@@ -3801,15 +3800,15 @@ static void b43_op_configure_filter(struct ieee80211_hw *hw,
                                     u64 multicast)
 {
         struct b43_wl *wl = hw_to_b43_wl(hw);
-        struct b43_wldev *dev = wl->current_dev;
-        unsigned long flags;
+        struct b43_wldev *dev;
 
+        mutex_lock(&wl->mutex);
+        dev = wl->current_dev;
         if (!dev) {
                 *fflags = 0;
-                return;
+                goto out_unlock;
         }
 
-        spin_lock_irqsave(&wl->irq_lock, flags);
         *fflags &= FIF_PROMISC_IN_BSS |
                   FIF_ALLMULTI |
                   FIF_FCSFAIL |
@@ -3830,41 +3829,66 @@ static void b43_op_configure_filter(struct ieee80211_hw *hw,
 
         if (changed && b43_status(dev) >= B43_STAT_INITIALIZED)
                 b43_adjust_opmode(dev);
-        spin_unlock_irqrestore(&wl->irq_lock, flags);
+
+out_unlock:
+        mutex_unlock(&wl->mutex);
 }
 
-/* Locking: wl->mutex */
-static void b43_wireless_core_stop(struct b43_wldev *dev)
+/* Locking: wl->mutex
+ * Returns the current dev. This might be different from the passed in dev,
+ * because the core might be gone away while we unlocked the mutex. */
+static struct b43_wldev * b43_wireless_core_stop(struct b43_wldev *dev)
 {
         struct b43_wl *wl = dev->wl;
-        unsigned long flags;
+        struct b43_wldev *orig_dev;
 
-        if (b43_status(dev) < B43_STAT_STARTED)
-                return;
+redo:
+        if (!dev || b43_status(dev) < B43_STAT_STARTED)
+                return dev;
 
-        /* Disable and sync interrupts. We must do this before than
-         * setting the status to INITIALIZED, as the interrupt handler
-         * won't care about IRQs then. */
-        spin_lock_irqsave(&wl->irq_lock, flags);
-        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);
+        /* Disable periodic work. Unlock to avoid deadlocks. */
+        mutex_unlock(&wl->mutex);
+        cancel_delayed_work_sync(&dev->periodic_work);
+        mutex_lock(&wl->mutex);
+        dev = wl->current_dev;
+        if (!dev || b43_status(dev) < B43_STAT_STARTED) {
+                /* Whoops, aliens ate up the device while we were unlocked. */
+                return dev;
+        }
 
-        write_lock_irqsave(&wl->tx_lock, flags);
+        /* Disable interrupts on the device. */
         b43_set_status(dev, B43_STAT_INITIALIZED);
-        write_unlock_irqrestore(&wl->tx_lock, flags);
-
-        b43_pio_stop(dev);
+        if (0 /*FIXME dev->dev->bus->bustype == SSB_BUSTYPE_SDIO*/) {
+                /* wl->mutex is locked. That is enough. */
+                b43_write32(dev, B43_MMIO_GEN_IRQ_MASK, 0);
+                b43_read32(dev, B43_MMIO_GEN_IRQ_MASK); /* Flush */
+        } else {
+                spin_lock_irq(&wl->hardirq_lock);
+                b43_write32(dev, B43_MMIO_GEN_IRQ_MASK, 0);
+                b43_read32(dev, B43_MMIO_GEN_IRQ_MASK); /* Flush */
+                spin_unlock_irq(&wl->hardirq_lock);
+        }
+        /* Synchronize the interrupt handlers. Unlock to avoid deadlocks. */
+        orig_dev = dev;
         mutex_unlock(&wl->mutex);
-        /* Must unlock as it would otherwise deadlock. No races here.
-         * Cancel the possibly running self-rearming periodic work. */
-        cancel_delayed_work_sync(&dev->periodic_work);
+        synchronize_irq(dev->dev->irq);
         mutex_lock(&wl->mutex);
+        dev = wl->current_dev;
+        if (!dev)
+                return dev;
+        if (dev != orig_dev) {
+                if (b43_status(dev) >= B43_STAT_STARTED)
+                        goto redo;
+                return dev;
+        }
+        B43_WARN_ON(b43_read32(dev, B43_MMIO_GEN_IRQ_MASK));
 
+        b43_pio_stop(dev);
         b43_mac_suspend(dev);
         free_irq(dev->dev->irq, dev);
         b43dbg(wl, "Wireless interface stopped\n");
+
+        return dev;
 }
 
 /* Locking: wl->mutex */
@@ -3875,8 +3899,9 @@ static int b43_wireless_core_start(struct b43_wldev *dev)
         B43_WARN_ON(b43_status(dev) != B43_STAT_INITIALIZED);
 
         drain_txstatus_queue(dev);
-        err = request_irq(dev->dev->irq, b43_interrupt_handler,
-                          IRQF_SHARED, KBUILD_MODNAME, dev);
+        err = request_threaded_irq(dev->dev->irq, b43_interrupt_handler,
+                                   b43_interrupt_thread_handler,
+                                   IRQF_SHARED, KBUILD_MODNAME, dev);
         if (err) {
                 b43err(dev->wl, "Cannot request IRQ-%d\n", dev->dev->irq);
                 goto out;
@@ -4155,8 +4180,8 @@ static void b43_wireless_core_exit(struct b43_wldev *dev)
 {
         u32 macctl;
 
-        B43_WARN_ON(b43_status(dev) > B43_STAT_INITIALIZED);
-        if (b43_status(dev) != B43_STAT_INITIALIZED)
+        B43_WARN_ON(dev && b43_status(dev) > B43_STAT_INITIALIZED);
+        if (!dev || b43_status(dev) != B43_STAT_INITIALIZED)
                 return;
         b43_set_status(dev, B43_STAT_UNINIT);
 
@@ -4309,7 +4334,6 @@ static int b43_op_add_interface(struct ieee80211_hw *hw,
 {
         struct b43_wl *wl = hw_to_b43_wl(hw);
         struct b43_wldev *dev;
-        unsigned long flags;
         int err = -EOPNOTSUPP;
 
         /* TODO: allow WDS/AP devices to coexist */
@@ -4333,12 +4357,10 @@ static int b43_op_add_interface(struct ieee80211_hw *hw,
         wl->if_type = conf->type;
         memcpy(wl->mac_addr, conf->mac_addr, ETH_ALEN);
 
-        spin_lock_irqsave(&wl->irq_lock, flags);
         b43_adjust_opmode(dev);
         b43_set_pretbtt(dev);
         b43_set_synth_pu_delay(dev, 0);
         b43_upload_card_macaddress(dev);
-        spin_unlock_irqrestore(&wl->irq_lock, flags);
 
         err = 0;
  out_mutex_unlock:
@@ -4352,7 +4374,6 @@ static void b43_op_remove_interface(struct ieee80211_hw *hw,
 {
         struct b43_wl *wl = hw_to_b43_wl(hw);
         struct b43_wldev *dev = wl->current_dev;
-        unsigned long flags;
 
         b43dbg(wl, "Removing Interface type %d\n", conf->type);
 
@@ -4364,11 +4385,9 @@ static void b43_op_remove_interface(struct ieee80211_hw *hw,
 
         wl->operating = 0;
 
-        spin_lock_irqsave(&wl->irq_lock, flags);
         b43_adjust_opmode(dev);
         memset(wl->mac_addr, 0, ETH_ALEN);
         b43_upload_card_macaddress(dev);
-        spin_unlock_irqrestore(&wl->irq_lock, flags);
 
         mutex_unlock(&wl->mutex);
 }
@@ -4428,10 +4447,15 @@ static void b43_op_stop(struct ieee80211_hw *hw)
         cancel_work_sync(&(wl->beacon_update_trigger));
 
         mutex_lock(&wl->mutex);
-        if (b43_status(dev) >= B43_STAT_STARTED)
-                b43_wireless_core_stop(dev);
+        if (b43_status(dev) >= B43_STAT_STARTED) {
+                dev = b43_wireless_core_stop(dev);
+                if (!dev)
+                        goto out_unlock;
+        }
         b43_wireless_core_exit(dev);
         wl->radio_enabled = 0;
+
+out_unlock:
         mutex_unlock(&wl->mutex);
 
         cancel_work_sync(&(wl->txpower_adjust_work));
@@ -4441,11 +4465,10 @@ static int b43_op_beacon_set_tim(struct ieee80211_hw *hw,
                                  struct ieee80211_sta *sta, bool set)
 {
         struct b43_wl *wl = hw_to_b43_wl(hw);
-        unsigned long flags;
 
-        spin_lock_irqsave(&wl->irq_lock, flags);
+        mutex_lock(&wl->mutex);
         b43_update_templates(wl);
-        spin_unlock_irqrestore(&wl->irq_lock, flags);
+        mutex_unlock(&wl->mutex);
 
         return 0;
 }
@@ -4526,8 +4549,13 @@ static void b43_chip_reset(struct work_struct *work)
 
         prev_status = b43_status(dev);
         /* Bring the device down... */
-        if (prev_status >= B43_STAT_STARTED)
-                b43_wireless_core_stop(dev);
+        if (prev_status >= B43_STAT_STARTED) {
+                dev = b43_wireless_core_stop(dev);
+                if (!dev) {
+                        err = -ENODEV;
+                        goto out;
+                }
+        }
         if (prev_status >= B43_STAT_INITIALIZED)
                 b43_wireless_core_exit(dev);
 
@@ -4742,9 +4770,6 @@ static int b43_one_core_attach(struct ssb_device *dev, struct b43_wl *wl)
         wldev->wl = wl;
         b43_set_status(wldev, B43_STAT_UNINIT);
         wldev->bad_frames_preempt = modparam_bad_frames_preempt;
-        tasklet_init(&wldev->isr_tasklet,
-                     (void (*)(unsigned long))b43_interrupt_tasklet,
-                     (unsigned long)wldev);
         INIT_LIST_HEAD(&wldev->list);
 
         err = b43_wireless_core_attach(wldev);
@@ -4841,11 +4866,11 @@ static int b43_wireless_init(struct ssb_device *dev)
 
         /* Initialize struct b43_wl */
         wl->hw = hw;
-        spin_lock_init(&wl->irq_lock);
         rwlock_init(&wl->tx_lock);
         spin_lock_init(&wl->leds_lock);
         spin_lock_init(&wl->shm_lock);
         mutex_init(&wl->mutex);
+        spin_lock_init(&wl->hardirq_lock);
         INIT_LIST_HEAD(&wl->devlist);
         INIT_WORK(&wl->beacon_update_trigger, b43_beacon_update_trigger_work);
         INIT_WORK(&wl->txpower_adjust_work, b43_phy_txpower_adjust_work);
@@ -4946,8 +4971,8 @@ static int b43_suspend(struct ssb_device *dev, pm_message_t state)
         wldev->suspend_in_progress = true;
         wldev->suspend_init_status = b43_status(wldev);
         if (wldev->suspend_init_status >= B43_STAT_STARTED)
-                b43_wireless_core_stop(wldev);
-        if (wldev->suspend_init_status >= B43_STAT_INITIALIZED)
+                wldev = b43_wireless_core_stop(wldev);
+        if (wldev && wldev->suspend_init_status >= B43_STAT_INITIALIZED)
                 b43_wireless_core_exit(wldev);
         mutex_unlock(&wl->mutex);
 
diff --git a/drivers/net/wireless/b43/phy_common.c b/drivers/net/wireless/b43/phy_common.c
index 6e704becda6f..75b26e175e8f 100644
--- a/drivers/net/wireless/b43/phy_common.c
+++ b/drivers/net/wireless/b43/phy_common.c
@@ -347,7 +347,6 @@ void b43_phy_txpower_adjust_work(struct work_struct *work)
         mutex_unlock(&wl->mutex);
 }
 
-/* Called with wl->irq_lock locked */
 void b43_phy_txpower_check(struct b43_wldev *dev, unsigned int flags)
 {
         struct b43_phy *phy = &dev->phy;
diff --git a/drivers/net/wireless/b43/phy_common.h b/drivers/net/wireless/b43/phy_common.h
index 28e384633c34..9edd4e8e0c85 100644
--- a/drivers/net/wireless/b43/phy_common.h
+++ b/drivers/net/wireless/b43/phy_common.h
@@ -131,7 +131,7 @@ enum b43_txpwr_result {
  *                      If the parameter "ignore_tssi" is true, the TSSI values should
  *                      be ignored and a recalculation of the power settings should be
  *                      done even if the TSSI values did not change.
- *                      This callback is called with wl->irq_lock held and must not sleep.
+ *                      This function may sleep, but should not.
  *                      Must not be NULL.
  * @adjust_txpower:     Write the previously calculated TX power settings
  *                      (from @recalc_txpower) to the hardware.
@@ -379,7 +379,6 @@ void b43_software_rfkill(struct b43_wldev *dev, bool blocked);
  *
  * Compare the current TX power output to the desired power emission
  * and schedule an adjustment in case it mismatches.
- * Requires wl->irq_lock locked.
  *
  * @flags:      OR'ed enum b43_phy_txpower_check_flags flags.
  *              See the docs below.
diff --git a/drivers/net/wireless/b43/phy_g.c b/drivers/net/wireless/b43/phy_g.c
index 5afa4df0b02f..382826a8da82 100644
--- a/drivers/net/wireless/b43/phy_g.c
+++ b/drivers/net/wireless/b43/phy_g.c
@@ -2823,8 +2823,6 @@ static void b43_gphy_op_adjust_txpower(struct b43_wldev *dev)
 
         b43_mac_suspend(dev);
 
-        spin_lock_irq(&dev->wl->irq_lock);
-
         /* Calculate the new attenuation values. */
         bbatt = gphy->bbatt.att;
         bbatt += gphy->bbatt_delta;
@@ -2864,11 +2862,6 @@ static void b43_gphy_op_adjust_txpower(struct b43_wldev *dev)
         gphy->rfatt.att = rfatt;
         gphy->bbatt.att = bbatt;
 
-        /* We drop the lock early, so we can sleep during hardware
-         * adjustment. Possible races with op_recalc_txpower are harmless,
-         * as we will be called once again in case we raced. */
-        spin_unlock_irq(&dev->wl->irq_lock);
-
         if (b43_debug(dev, B43_DBG_XMITPOWER))
                 b43dbg(dev->wl, "Adjusting TX power\n");
 
diff --git a/drivers/net/wireless/b43/phy_g.h b/drivers/net/wireless/b43/phy_g.h
index 718947fd41ae..8569fdd4c6be 100644
--- a/drivers/net/wireless/b43/phy_g.h
+++ b/drivers/net/wireless/b43/phy_g.h
@@ -141,8 +141,7 @@ struct b43_phy_g {
         int tgt_idle_tssi;
         /* Current idle TSSI */
         int cur_idle_tssi;
-        /* The current average TSSI.
-         * Needs irq_lock, as it's updated in the IRQ path. */
+        /* The current average TSSI. */
         u8 average_tssi;
         /* Current TX power level attenuation control values */
         struct b43_bbatt bbatt;
diff --git a/drivers/net/wireless/b43/pio.c b/drivers/net/wireless/b43/pio.c
index 3fd653c78b10..ce6f36eb88ca 100644
--- a/drivers/net/wireless/b43/pio.c
+++ b/drivers/net/wireless/b43/pio.c
@@ -570,7 +570,6 @@ out_unlock:
         return err;
 }
 
-/* Called with IRQs disabled. */
 void b43_pio_handle_txstatus(struct b43_wldev *dev,
                              const struct b43_txstatus *status)
 {
@@ -584,7 +583,7 @@ void b43_pio_handle_txstatus(struct b43_wldev *dev,
                 return;
         B43_WARN_ON(!pack);
 
-        spin_lock(&q->lock); /* IRQs are already disabled. */
+        spin_lock_irq(&q->lock);
 
         info = IEEE80211_SKB_CB(pack->skb);
 
@@ -604,7 +603,7 @@ void b43_pio_handle_txstatus(struct b43_wldev *dev,
                 q->stopped = 0;
         }
 
-        spin_unlock(&q->lock);
+        spin_unlock_irq(&q->lock);
 }
 
 void b43_pio_get_tx_stats(struct b43_wldev *dev,
diff --git a/drivers/net/wireless/b43/sysfs.c b/drivers/net/wireless/b43/sysfs.c
index 5adaa3692d75..f1ae4e05a32c 100644
--- a/drivers/net/wireless/b43/sysfs.c
+++ b/drivers/net/wireless/b43/sysfs.c
@@ -94,7 +94,6 @@ static ssize_t b43_attr_interfmode_store(struct device *dev,
                                          const char *buf, size_t count)
 {
         struct b43_wldev *wldev = dev_to_b43_wldev(dev);
-        unsigned long flags;
         int err;
         int mode;
 
@@ -120,7 +119,6 @@ static ssize_t b43_attr_interfmode_store(struct device *dev,
         }
 
         mutex_lock(&wldev->wl->mutex);
-        spin_lock_irqsave(&wldev->wl->irq_lock, flags);
 
         if (wldev->phy.ops->interf_mitigation) {
                 err = wldev->phy.ops->interf_mitigation(wldev, mode);
@@ -132,7 +130,6 @@ static ssize_t b43_attr_interfmode_store(struct device *dev,
                 err = -ENOSYS;
 
         mmiowb();
-        spin_unlock_irqrestore(&wldev->wl->irq_lock, flags);
         mutex_unlock(&wldev->wl->mutex);
 
         return err ? err : count;