[PATCH] bcm43xx: Abstract the locking mechanism.

This is the starting point to make the driver out-of-order-MMIO-stores safe.
There are more mmiowb() needed.

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

drivers/net/wireless/bcm43xx/bcm43xx.h

@@ -619,7 +619,9 @@ struct bcm43xx_private {
 	void __iomem *mmio_addr;
 	unsigned int mmio_len;
 
-	spinlock_t lock;
+	/* Do not use the lock directly. Use the bcm43xx_lock* helper
+	 * functions, to be MMIO-safe. */
+	spinlock_t _lock;
 
 	/* Driver status flags. */
 	u32 initialized:1,		/* init_board() succeed */
@@ -721,6 +723,22 @@ struct bcm43xx_private {
 #endif
 };
 
+/* bcm43xx_(un)lock() protect struct bcm43xx_private.
+ * Note that _NO_ MMIO writes are allowed. If you want to
+ * write to the device through MMIO in the critical section, use
+ * the *_mmio lock functions.
+ * MMIO read-access is allowed, though.
+ */
+#define bcm43xx_lock(bcm, flags)	spin_lock_irqsave(&(bcm)->_lock, flags)
+#define bcm43xx_unlock(bcm, flags)	spin_unlock_irqrestore(&(bcm)->_lock, flags)
+/* bcm43xx_(un)lock_mmio() protect struct bcm43xx_private and MMIO.
+ * MMIO write-access to the device is allowed.
+ * All MMIO writes are flushed on unlock, so it is guaranteed to not
+ * interfere with other threads writing MMIO registers.
+ */
+#define bcm43xx_lock_mmio(bcm, flags)	bcm43xx_lock(bcm, flags)
+#define bcm43xx_unlock_mmio(bcm, flags)	do { mmiowb(); bcm43xx_unlock(bcm, flags); } while (0)
+
 static inline
 struct bcm43xx_private * bcm43xx_priv(struct net_device *dev)
 {

drivers/net/wireless/bcm43xx/bcm43xx_debugfs.c

@@ -77,7 +77,7 @@ static ssize_t devinfo_read_file(struct file *file, char __user *userbuf,
 
 	down(&big_buffer_sem);
 
-	spin_lock_irqsave(&bcm->lock, flags);
+	bcm43xx_lock_mmio(bcm, flags);
 	if (!bcm->initialized) {
 		fappend("Board not initialized.\n");
 		goto out;
@@ -124,7 +124,7 @@ static ssize_t devinfo_read_file(struct file *file, char __user *userbuf,
 	fappend("\n");
 
 out:
-	spin_unlock_irqrestore(&bcm->lock, flags);
+	bcm43xx_unlock_mmio(bcm, flags);
 	res = simple_read_from_buffer(userbuf, count, ppos, buf, pos);
 	up(&big_buffer_sem);
 	return res;
@@ -162,7 +162,7 @@ static ssize_t spromdump_read_file(struct file *file, char __user *userbuf,
 	unsigned long flags;
 
 	down(&big_buffer_sem);
-	spin_lock_irqsave(&bcm->lock, flags);
+	bcm43xx_lock_mmio(bcm, flags);
 	if (!bcm->initialized) {
 		fappend("Board not initialized.\n");
 		goto out;
@@ -172,7 +172,7 @@ static ssize_t spromdump_read_file(struct file *file, char __user *userbuf,
 	fappend("boardflags: 0x%04x\n", bcm->sprom.boardflags);
 
 out:
-	spin_unlock_irqrestore(&bcm->lock, flags);
+	bcm43xx_unlock_mmio(bcm, flags);
 	res = simple_read_from_buffer(userbuf, count, ppos, buf, pos);
 	up(&big_buffer_sem);
 	return res;
@@ -191,7 +191,7 @@ static ssize_t tsf_read_file(struct file *file, char __user *userbuf,
 	u64 tsf;
 
 	down(&big_buffer_sem);
-	spin_lock_irqsave(&bcm->lock, flags);
+	bcm43xx_lock_mmio(bcm, flags);
 	if (!bcm->initialized) {
 		fappend("Board not initialized.\n");
 		goto out;
@@ -202,7 +202,7 @@ static ssize_t tsf_read_file(struct file *file, char __user *userbuf,
 		(unsigned int)(tsf & 0xFFFFFFFFULL));
 
 out:
-	spin_unlock_irqrestore(&bcm->lock, flags);
+	bcm43xx_unlock_mmio(bcm, flags);
 	res = simple_read_from_buffer(userbuf, count, ppos, buf, pos);
 	up(&big_buffer_sem);
 	return res;
@@ -224,7 +224,7 @@ static ssize_t tsf_write_file(struct file *file, const char __user *user_buf,
 	        res = -EFAULT;
 		goto out_up;
 	}
-	spin_lock_irqsave(&bcm->lock, flags);
+	bcm43xx_lock_mmio(bcm, flags);
 	if (!bcm->initialized) {
 		printk(KERN_INFO PFX "debugfs: Board not initialized.\n");
 		res = -EFAULT;
@@ -239,7 +239,7 @@ static ssize_t tsf_write_file(struct file *file, const char __user *user_buf,
 	res = buf_size;
 
 out_unlock:
-	spin_unlock_irqrestore(&bcm->lock, flags);
+	bcm43xx_unlock_mmio(bcm, flags);
 out_up:
 	up(&big_buffer_sem);
 	return res;
@@ -260,7 +260,7 @@ static ssize_t txstat_read_file(struct file *file, char __user *userbuf,
 	int i, cnt, j = 0;
 
 	down(&big_buffer_sem);
-	spin_lock_irqsave(&bcm->lock, flags);
+	bcm43xx_lock(bcm, flags);
 
 	fappend("Last %d logged xmitstatus blobs (Latest first):\n\n",
 		BCM43xx_NR_LOGGED_XMITSTATUS);
@@ -296,14 +296,14 @@ static ssize_t txstat_read_file(struct file *file, char __user *userbuf,
 			i = BCM43xx_NR_LOGGED_XMITSTATUS - 1;
 	}
 
-	spin_unlock_irqrestore(&bcm->lock, flags);
+	bcm43xx_unlock(bcm, flags);
 	res = simple_read_from_buffer(userbuf, count, ppos, buf, pos);
-	spin_lock_irqsave(&bcm->lock, flags);
+	bcm43xx_lock(bcm, flags);
 	if (*ppos == pos) {
 		/* Done. Drop the copied data. */
 		e->xmitstatus_printing = 0;
 	}
-	spin_unlock_irqrestore(&bcm->lock, flags);
+	bcm43xx_unlock(bcm, flags);
 	up(&big_buffer_sem);
 	return res;
 }
@@ -419,7 +419,7 @@ void bcm43xx_debugfs_log_txstat(struct bcm43xx_private *bcm,
 	struct bcm43xx_dfsentry *e;
 	struct bcm43xx_xmitstatus *savedstatus;
 
-	/* This is protected by bcm->lock */
+	/* This is protected by bcm->_lock */
 	e = bcm->dfsentry;
 	assert(e);
 	savedstatus = e->xmitstatus_buffer + e->xmitstatus_ptr;

drivers/net/wireless/bcm43xx/bcm43xx_leds.c

@@ -51,12 +51,12 @@ static void bcm43xx_led_blink(unsigned long d)
 	struct bcm43xx_private *bcm = led->bcm;
 	unsigned long flags;
 
-	spin_lock_irqsave(&bcm->lock, flags);
+	bcm43xx_lock_mmio(bcm, flags);
 	if (led->blink_interval) {
 		bcm43xx_led_changestate(led);
 		mod_timer(&led->blink_timer, jiffies + led->blink_interval);
 	}
-	spin_unlock_irqrestore(&bcm->lock, flags);
+	bcm43xx_unlock_mmio(bcm, flags);
 }
 
 static void bcm43xx_led_blink_start(struct bcm43xx_led *led,

drivers/net/wireless/bcm43xx/bcm43xx_main.c

@@ -482,14 +482,14 @@ static int bcm43xx_disable_interrupts_sync(struct bcm43xx_private *bcm, u32 *old
 	u32 old;
 	unsigned long flags;
 
-	spin_lock_irqsave(&bcm->lock, flags);
+	bcm43xx_lock_mmio(bcm, flags);
 	if (bcm43xx_is_initializing(bcm) || bcm->shutting_down) {
-		spin_unlock_irqrestore(&bcm->lock, flags);
+		bcm43xx_unlock_mmio(bcm, flags);
 		return -EBUSY;
 	}
 	old = bcm43xx_interrupt_disable(bcm, BCM43xx_IRQ_ALL);
 	tasklet_disable(&bcm->isr_tasklet);
-	spin_unlock_irqrestore(&bcm->lock, flags);
+	bcm43xx_unlock_mmio(bcm, flags);
 	if (oldstate)
 		*oldstate = old;
 
@@ -746,6 +746,7 @@ int bcm43xx_sprom_write(struct bcm43xx_private *bcm, const u16 *sprom)
 		else if (i % 2)
 			printk(".");
 		bcm43xx_write16(bcm, BCM43xx_SPROM_BASE + (i * 2), sprom[i]);
+		mmiowb();
 		mdelay(20);
 	}
 	spromctl &= ~0x10; /* SPROM WRITE enable. */
@@ -1676,7 +1677,7 @@ static void bcm43xx_interrupt_tasklet(struct bcm43xx_private *bcm)
 # define bcmirq_handled(irq)	do { /* nothing */ } while (0)
 #endif /* CONFIG_BCM43XX_DEBUG*/
 
-	spin_lock_irqsave(&bcm->lock, flags);
+	bcm43xx_lock_mmio(bcm, flags);
 	reason = bcm->irq_reason;
 	dma_reason[0] = bcm->dma_reason[0];
 	dma_reason[1] = bcm->dma_reason[1];
@@ -1776,7 +1777,7 @@ static void bcm43xx_interrupt_tasklet(struct bcm43xx_private *bcm)
 	if (!modparam_noleds)
 		bcm43xx_leds_update(bcm, activity);
 	bcm43xx_interrupt_enable(bcm, bcm->irq_savedstate);
-	spin_unlock_irqrestore(&bcm->lock, flags);
+	bcm43xx_unlock_mmio(bcm, flags);
 }
 
 #undef bcmirq_print_reasons
@@ -1830,25 +1831,24 @@ static void bcm43xx_interrupt_ack(struct bcm43xx_private *bcm,
 /* Interrupt handler top-half */
 static irqreturn_t bcm43xx_interrupt_handler(int irq, void *dev_id, struct pt_regs *regs)
 {
+	irqreturn_t ret = IRQ_HANDLED;
 	struct bcm43xx_private *bcm = dev_id;
 	u32 reason, mask;
 
 	if (!bcm)
 		return IRQ_NONE;
 
-	spin_lock(&bcm->lock);
+	spin_lock(&bcm->_lock);
 
 	reason = bcm43xx_read32(bcm, BCM43xx_MMIO_GEN_IRQ_REASON);
 	if (reason == 0xffffffff) {
 		/* irq not for us (shared irq) */
-		spin_unlock(&bcm->lock);
-		return IRQ_NONE;
+		ret = IRQ_NONE;
+		goto out;
 	}
 	mask = bcm43xx_read32(bcm, BCM43xx_MMIO_GEN_IRQ_MASK);
-	if (!(reason & mask)) {
-		spin_unlock(&bcm->lock);
-		return IRQ_HANDLED;
-	}
+	if (!(reason & mask))
+		goto out;
 
 	bcm43xx_interrupt_ack(bcm, reason, mask);
 
@@ -1866,9 +1866,11 @@ static irqreturn_t bcm43xx_interrupt_handler(int irq, void *dev_id, struct pt_re
 		tasklet_schedule(&bcm->isr_tasklet);
 	}
 
-	spin_unlock(&bcm->lock);
+out:
+	mmiowb();
+	spin_unlock(&bcm->_lock);
 
-	return IRQ_HANDLED;
+	return ret;
 }
 
 static void bcm43xx_release_firmware(struct bcm43xx_private *bcm, int force)
@@ -3112,7 +3114,7 @@ static void bcm43xx_periodic_task_handler(unsigned long d)
 	unsigned long flags;
 	unsigned int state;
 
-	spin_lock_irqsave(&bcm->lock, flags);
+	bcm43xx_lock_mmio(bcm, flags);
 
 	assert(bcm->initialized);
 	state = bcm->periodic_state;
@@ -3127,7 +3129,7 @@ static void bcm43xx_periodic_task_handler(unsigned long d)
 
 	mod_timer(&bcm->periodic_tasks, jiffies + (HZ * 15));
 
-	spin_unlock_irqrestore(&bcm->lock, flags);
+	bcm43xx_unlock_mmio(bcm, flags);
 }
 
 static void bcm43xx_periodic_tasks_delete(struct bcm43xx_private *bcm)
@@ -3164,10 +3166,10 @@ static void bcm43xx_free_board(struct bcm43xx_private *bcm)
 
 	bcm43xx_periodic_tasks_delete(bcm);
 
-	spin_lock_irqsave(&bcm->lock, flags);
+	bcm43xx_lock(bcm, flags);
 	bcm->initialized = 0;
 	bcm->shutting_down = 1;
-	spin_unlock_irqrestore(&bcm->lock, flags);
+	bcm43xx_unlock(bcm, flags);
 
 	for (i = 0; i < BCM43xx_MAX_80211_CORES; i++) {
 		if (!(bcm->core_80211[i].flags & BCM43xx_COREFLAG_AVAILABLE))
@@ -3182,9 +3184,9 @@ static void bcm43xx_free_board(struct bcm43xx_private *bcm)
 
 	bcm43xx_pctl_set_crystal(bcm, 0);
 
-	spin_lock_irqsave(&bcm->lock, flags);
+	bcm43xx_lock(bcm, flags);
 	bcm->shutting_down = 0;
-	spin_unlock_irqrestore(&bcm->lock, flags);
+	bcm43xx_unlock(bcm, flags);
 }
 
 static int bcm43xx_init_board(struct bcm43xx_private *bcm)
@@ -3196,10 +3198,10 @@ static int bcm43xx_init_board(struct bcm43xx_private *bcm)
 
 	might_sleep();
 
-	spin_lock_irqsave(&bcm->lock, flags);
+	bcm43xx_lock(bcm, flags);
 	bcm->initialized = 0;
 	bcm->shutting_down = 0;
-	spin_unlock_irqrestore(&bcm->lock, flags);
+	bcm43xx_unlock(bcm, flags);
 
 	err = bcm43xx_pctl_set_crystal(bcm, 1);
 	if (err)
@@ -3267,9 +3269,9 @@ static int bcm43xx_init_board(struct bcm43xx_private *bcm)
 	}
 
 	/* Initialization of the board is done. Flag it as such. */
-	spin_lock_irqsave(&bcm->lock, flags);
+	bcm43xx_lock(bcm, flags);
 	bcm->initialized = 1;
-	spin_unlock_irqrestore(&bcm->lock, flags);
+	bcm43xx_unlock(bcm, flags);
 
 	bcm43xx_periodic_tasks_setup(bcm);
 	bcm43xx_sysfs_register(bcm);
@@ -3570,11 +3572,11 @@ static void bcm43xx_ieee80211_set_chan(struct net_device *net_dev,
 	struct bcm43xx_private *bcm = bcm43xx_priv(net_dev);
 	unsigned long flags;
 
-	spin_lock_irqsave(&bcm->lock, flags);
+	bcm43xx_lock_mmio(bcm, flags);
 	bcm43xx_mac_suspend(bcm);
 	bcm43xx_radio_selectchannel(bcm, channel, 0);
 	bcm43xx_mac_enable(bcm);
-	spin_unlock_irqrestore(&bcm->lock, flags);
+	bcm43xx_unlock_mmio(bcm, flags);
 }
 
 /* set_security() callback in struct ieee80211_device */
@@ -3587,9 +3589,9 @@ static void bcm43xx_ieee80211_set_security(struct net_device *net_dev,
 	int keyidx;
 
 	dprintk(KERN_INFO PFX "set security called\n");
-	
-	spin_lock_irqsave(&bcm->lock, flags);
-	
+
+	bcm43xx_lock_mmio(bcm, flags);
+
 	for (keyidx = 0; keyidx<WEP_KEYS; keyidx++)
 		if (sec->flags & (1<<keyidx)) {
 			secinfo->encode_alg[keyidx] = sec->encode_alg[keyidx];
@@ -3651,7 +3653,7 @@ static void bcm43xx_ieee80211_set_security(struct net_device *net_dev,
 		} else
 				bcm43xx_clear_keys(bcm);
 	}
-	spin_unlock_irqrestore(&bcm->lock, flags);
+	bcm43xx_unlock_mmio(bcm, flags);
 }
 
 /* hard_start_xmit() callback in struct ieee80211_device */
@@ -3663,10 +3665,10 @@ static int bcm43xx_ieee80211_hard_start_xmit(struct ieee80211_txb *txb,
 	int err = -ENODEV;
 	unsigned long flags;
 
-	spin_lock_irqsave(&bcm->lock, flags);
+	bcm43xx_lock_mmio(bcm, flags);
 	if (likely(bcm->initialized))
 		err = bcm43xx_tx(bcm, txb);
-	spin_unlock_irqrestore(&bcm->lock, flags);
+	bcm43xx_unlock_mmio(bcm, flags);
 
 	return err;
 }
@@ -3679,8 +3681,11 @@ static struct net_device_stats * bcm43xx_net_get_stats(struct net_device *net_de
 static void bcm43xx_net_tx_timeout(struct net_device *net_dev)
 {
 	struct bcm43xx_private *bcm = bcm43xx_priv(net_dev);
+	unsigned long flags;
 
+	bcm43xx_lock_mmio(bcm, flags);
 	bcm43xx_controller_restart(bcm, "TX timeout");
+	bcm43xx_unlock_mmio(bcm, flags);
 }
 
 #ifdef CONFIG_NET_POLL_CONTROLLER
@@ -3738,7 +3743,7 @@ static int bcm43xx_init_private(struct bcm43xx_private *bcm,
 	bcm->pci_dev = pci_dev;
 	bcm->net_dev = net_dev;
 	bcm->bad_frames_preempt = modparam_bad_frames_preempt;
-	spin_lock_init(&bcm->lock);
+	spin_lock_init(&bcm->_lock);
 	tasklet_init(&bcm->isr_tasklet,
 		     (void (*)(unsigned long))bcm43xx_interrupt_tasklet,
 		     (unsigned long)bcm);
@@ -3921,11 +3926,11 @@ static int bcm43xx_suspend(struct pci_dev *pdev, pm_message_t state)
 
 	dprintk(KERN_INFO PFX "Suspending...\n");
 
-	spin_lock_irqsave(&bcm->lock, flags);
+	bcm43xx_lock(bcm, flags);
 	bcm->was_initialized = bcm->initialized;
 	if (bcm->initialized)
 		try_to_shutdown = 1;
-	spin_unlock_irqrestore(&bcm->lock, flags);
+	bcm43xx_unlock(bcm, flags);
 
 	netif_device_detach(net_dev);
 	if (try_to_shutdown) {