Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc

Pull powerpc merge from Benjamin Herrenschmidt:
 "Here's the powerpc batch for this merge window.  It is going to be a
  bit more nasty than usual as in touching things outside of
  arch/powerpc mostly due to the big iSeriesectomy :-) We finally got
  rid of the bugger (legacy iSeries support) which was a PITA to
  maintain and that nobody really used anymore.

  Here are some of the highlights:

   - Legacy iSeries is gone.  Thanks Stephen ! There's still some bits
     and pieces remaining if you do a grep -ir series arch/powerpc but
     they are harmless and will be removed in the next few weeks
     hopefully.

   - The 'fadump' functionality (Firmware Assisted Dump) replaces the
     previous (equivalent) "pHyp assisted dump"...  it's a rewrite of a
     mechanism to get the hypervisor to do crash dumps on pSeries, the
     new implementation hopefully being much more reliable.  Thanks
     Mahesh Salgaonkar.

   - The "EEH" code (pSeries PCI error handling & recovery) got a big
     spring cleaning, motivated by the need to be able to implement a
     new backend for it on top of some new different type of firwmare.

     The work isn't complete yet, but a good chunk of the cleanups is
     there.  Note that this adds a field to struct device_node which is
     not very nice and which Grant objects to.  I will have a patch soon
     that moves that to a powerpc private data structure (hopefully
     before rc1) and we'll improve things further later on (hopefully
     getting rid of the need for that pointer completely).  Thanks Gavin
     Shan.

   - I dug into our exception & interrupt handling code to improve the
     way we do lazy interrupt handling (and make it work properly with
     "edge" triggered interrupt sources), and while at it found & fixed
     a wagon of issues in those areas, including adding support for page
     fault retry & fatal signals on page faults.

   - Your usual random batch of small fixes & updates, including a bunch
     of new embedded boards, both Freescale and APM based ones, etc..."

I fixed up some conflicts with the generalized irq-domain changes from
Grant Likely, hopefully correctly.

* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (141 commits)
  powerpc/ps3: Do not adjust the wrapper load address
  powerpc: Remove the rest of the legacy iSeries include files
  powerpc: Remove the remaining CONFIG_PPC_ISERIES pieces
  init: Remove CONFIG_PPC_ISERIES
  powerpc: Remove FW_FEATURE ISERIES from arch code
  tty/hvc_vio: FW_FEATURE_ISERIES is no longer selectable
  powerpc/spufs: Fix double unlocks
  powerpc/5200: convert mpc5200 to use of_platform_populate()
  powerpc/mpc5200: add options to mpc5200_defconfig
  powerpc/mpc52xx: add a4m072 board support
  powerpc/mpc5200: update mpc5200_defconfig to fit for charon board
  Documentation/powerpc/mpc52xx.txt: Checkpatch cleanup
  powerpc/44x: Add additional device support for APM821xx SoC and Bluestone board
  powerpc/44x: Add support PCI-E for APM821xx SoC and Bluestone board
  MAINTAINERS: Update PowerPC 4xx tree
  powerpc/44x: The bug fixed support for APM821xx SoC and Bluestone board
  powerpc: document the FSL MPIC message register binding
  powerpc: add support for MPIC message register API
  powerpc/fsl: Added aliased MSIIR register address to MSI node in dts
  powerpc/85xx: mpc8548cds - add 36-bit dts
  ...

drivers/misc/carma/carma-fpga.c

@@ -560,6 +560,9 @@ static void data_enable_interrupts(struct fpga_device *priv)
 
 	/* flush the writes */
 	fpga_read_reg(priv, 0, MMAP_REG_STATUS);
+	fpga_read_reg(priv, 1, MMAP_REG_STATUS);
+	fpga_read_reg(priv, 2, MMAP_REG_STATUS);
+	fpga_read_reg(priv, 3, MMAP_REG_STATUS);
 
 	/* switch back to the external interrupt source */
 	iowrite32be(0x3F, priv->regs + SYS_IRQ_SOURCE_CTL);
@@ -591,8 +594,12 @@ static void data_dma_cb(void *data)
 	list_move_tail(&priv->inflight->entry, &priv->used);
 	priv->inflight = NULL;
 
-	/* clear the FPGA status and re-enable interrupts */
-	data_enable_interrupts(priv);
+	/*
+	 * If data dumping is still enabled, then clear the FPGA
+	 * status registers and re-enable FPGA interrupts
+	 */
+	if (priv->enabled)
+		data_enable_interrupts(priv);
 
 	spin_unlock_irqrestore(&priv->lock, flags);
 
@@ -708,6 +715,15 @@ static irqreturn_t data_irq(int irq, void *dev_id)
 
 	spin_lock(&priv->lock);
 
+	/*
+	 * This is an error case that should never happen.
+	 *
+	 * If this driver has a bug and manages to re-enable interrupts while
+	 * a DMA is in progress, then we will hit this statement and should
+	 * start paying attention immediately.
+	 */
+	BUG_ON(priv->inflight != NULL);
+
 	/* hide the interrupt by switching the IRQ driver to GPIO */
 	data_disable_interrupts(priv);
 
@@ -762,11 +778,15 @@ out:
  */
 static int data_device_enable(struct fpga_device *priv)
 {
+	bool enabled;
 	u32 val;
 	int ret;
 
 	/* multiple enables are safe: they do nothing */
-	if (priv->enabled)
+	spin_lock_irq(&priv->lock);
+	enabled = priv->enabled;
+	spin_unlock_irq(&priv->lock);
+	if (enabled)
 		return 0;
 
 	/* check that the FPGAs are programmed */
@@ -797,6 +817,9 @@ static int data_device_enable(struct fpga_device *priv)
 		goto out_error;
 	}
 
+	/* prevent the FPGAs from generating interrupts */
+	data_disable_interrupts(priv);
+
 	/* hookup the irq handler */
 	ret = request_irq(priv->irq, data_irq, IRQF_SHARED, drv_name, priv);
 	if (ret) {
@@ -804,11 +827,13 @@ static int data_device_enable(struct fpga_device *priv)
 		goto out_error;
 	}
 
-	/* switch to the external FPGA IRQ line */
-	data_enable_interrupts(priv);
-
-	/* success, we're enabled */
+	/* allow the DMA callback to re-enable FPGA interrupts */
+	spin_lock_irq(&priv->lock);
 	priv->enabled = true;
+	spin_unlock_irq(&priv->lock);
+
+	/* allow the FPGAs to generate interrupts */
+	data_enable_interrupts(priv);
 	return 0;
 
 out_error:
@@ -834,41 +859,40 @@ out_error:
  */
 static int data_device_disable(struct fpga_device *priv)
 {
-	int ret;
+	spin_lock_irq(&priv->lock);
 
 	/* allow multiple disable */
-	if (!priv->enabled)
+	if (!priv->enabled) {
+		spin_unlock_irq(&priv->lock);
 		return 0;
+	}
 
-	/* switch to the internal GPIO IRQ line */
+	/*
+	 * Mark the device disabled
+	 *
+	 * This stops DMA callbacks from re-enabling interrupts
+	 */
+	priv->enabled = false;
+
+	/* prevent the FPGAs from generating interrupts */
 	data_disable_interrupts(priv);
 
+	/* wait until all ongoing DMA has finished */
+	while (priv->inflight != NULL) {
+		spin_unlock_irq(&priv->lock);
+		wait_event(priv->wait, priv->inflight == NULL);
+		spin_lock_irq(&priv->lock);
+	}
+
+	spin_unlock_irq(&priv->lock);
+
 	/* unhook the irq handler */
 	free_irq(priv->irq, priv);
 
-	/*
-	 * wait for all outstanding DMA to complete
-	 *
-	 * Device interrupts are disabled, therefore another buffer cannot
-	 * be marked inflight.
-	 */
-	ret = wait_event_interruptible(priv->wait, priv->inflight == NULL);
-	if (ret)
-		return ret;
-
 	/* free the correlation table */
 	sg_free_table(&priv->corl_table);
 	priv->corl_nents = 0;
 
-	/*
-	 * We are taking the spinlock not to protect priv->enabled, but instead
-	 * to make sure that there are no readers in the process of altering
-	 * the free or used lists while we are setting this flag.
-	 */
-	spin_lock_irq(&priv->lock);
-	priv->enabled = false;
-	spin_unlock_irq(&priv->lock);
-
 	/* free all buffers: the free and used lists are not being changed */
 	data_free_buffers(priv);
 	return 0;
@@ -896,15 +920,6 @@ static unsigned int list_num_entries(struct list_head *list)
 static int data_debug_show(struct seq_file *f, void *offset)
 {
 	struct fpga_device *priv = f->private;
-	int ret;
-
-	/*
-	 * Lock the mutex first, so that we get an accurate value for enable
-	 * Lock the spinlock next, to get accurate list counts
-	 */
-	ret = mutex_lock_interruptible(&priv->mutex);
-	if (ret)
-		return ret;
 
 	spin_lock_irq(&priv->lock);
 
@@ -917,7 +932,6 @@ static int data_debug_show(struct seq_file *f, void *offset)
 	seq_printf(f, "num_dropped: %d\n", priv->num_dropped);
 
 	spin_unlock_irq(&priv->lock);
-	mutex_unlock(&priv->mutex);
 	return 0;
 }
 
@@ -970,7 +984,13 @@ static ssize_t data_en_show(struct device *dev, struct device_attribute *attr,
 			    char *buf)
 {
 	struct fpga_device *priv = dev_get_drvdata(dev);
-	return snprintf(buf, PAGE_SIZE, "%u\n", priv->enabled);
+	int ret;
+
+	spin_lock_irq(&priv->lock);
+	ret = snprintf(buf, PAGE_SIZE, "%u\n", priv->enabled);
+	spin_unlock_irq(&priv->lock);
+
+	return ret;
 }
 
 static ssize_t data_en_set(struct device *dev, struct device_attribute *attr,
@@ -986,6 +1006,7 @@ static ssize_t data_en_set(struct device *dev, struct device_attribute *attr,
 		return -EINVAL;
 	}
 
+	/* protect against concurrent enable/disable */
 	ret = mutex_lock_interruptible(&priv->mutex);
 	if (ret)
 		return ret;
@@ -1079,6 +1100,7 @@ static ssize_t data_read(struct file *filp, char __user *ubuf, size_t count,
 	struct fpga_reader *reader = filp->private_data;
 	struct fpga_device *priv = reader->priv;
 	struct list_head *used = &priv->used;
+	bool drop_buffer = false;
 	struct data_buf *dbuf;
 	size_t avail;
 	void *data;
@@ -1166,10 +1188,12 @@ have_buffer:
 	 * One of two things has happened, the device is disabled, or the
 	 * device has been reconfigured underneath us. In either case, we
 	 * should just throw away the buffer.
+	 *
+	 * Lockdep complains if this is done under the spinlock, so we
+	 * handle it during the unlock path.
 	 */
 	if (!priv->enabled || dbuf->size != priv->bufsize) {
-		videobuf_dma_unmap(priv->dev, &dbuf->vb);
-		data_free_buffer(dbuf);
+		drop_buffer = true;
 		goto out_unlock;
 	}
 
@@ -1178,6 +1202,12 @@ have_buffer:
 
 out_unlock:
 	spin_unlock_irq(&priv->lock);
+
+	if (drop_buffer) {
+		videobuf_dma_unmap(priv->dev, &dbuf->vb);
+		data_free_buffer(dbuf);
+	}
+
 	return count;
 }