Merge remote branch '52xx-and-virtex/next'

6 files changed, 737 insertions, 12 deletions

diff --git a/arch/powerpc/include/asm/mpc52xx.h b/arch/powerpc/include/asm/mpc52xx.h
index 1b4f697abbdd..707ab7590cfb 100644
--- a/arch/powerpc/include/asm/mpc52xx.h
+++ b/arch/powerpc/include/asm/mpc52xx.h
@@ -276,6 +276,52 @@ extern int mpc52xx_set_psc_clkdiv(int psc_id, int clkdiv);
 extern unsigned int mpc52xx_get_xtal_freq(struct device_node *node);
 extern void mpc52xx_restart(char *cmd);
 
+/* mpc52xx_gpt.c */
+struct mpc52xx_gpt_priv;
+extern struct mpc52xx_gpt_priv *mpc52xx_gpt_from_irq(int irq);
+extern int mpc52xx_gpt_start_timer(struct mpc52xx_gpt_priv *gpt, int period,
+                            int continuous);
+extern void mpc52xx_gpt_stop_timer(struct mpc52xx_gpt_priv *gpt);
+
+/* mpc52xx_lpbfifo.c */
+#define MPC52XX_LPBFIFO_FLAG_READ		(0)
+#define MPC52XX_LPBFIFO_FLAG_WRITE		(1<<0)
+#define MPC52XX_LPBFIFO_FLAG_NO_INCREMENT	(1<<1)
+#define MPC52XX_LPBFIFO_FLAG_NO_DMA		(1<<2)
+#define MPC52XX_LPBFIFO_FLAG_POLL_DMA		(1<<3)
+
+struct mpc52xx_lpbfifo_request {
+	struct list_head list;
+
+	/* localplus bus address */
+	unsigned int cs;
+	size_t offset;
+
+	/* Memory address */
+	void *data;
+	phys_addr_t data_phys;
+
+	/* Details of transfer */
+	size_t size;
+	size_t pos;	/* current position of transfer */
+	int flags;
+
+	/* What to do when finished */
+	void (*callback)(struct mpc52xx_lpbfifo_request *);
+
+	void *priv;		/* Driver private data */
+
+	/* statistics */
+	int irq_count;
+	int irq_ticks;
+	u8 last_byte;
+	int buffer_not_done_cnt;
+};
+
+extern int mpc52xx_lpbfifo_submit(struct mpc52xx_lpbfifo_request *req);
+extern void mpc52xx_lpbfifo_abort(struct mpc52xx_lpbfifo_request *req);
+extern void mpc52xx_lpbfifo_poll(void);
+
 /* mpc52xx_pic.c */
 extern void mpc52xx_init_irq(void);
 extern unsigned int mpc52xx_get_irq(void);
diff --git a/arch/powerpc/kernel/io.c b/arch/powerpc/kernel/io.c
index 1882bf419fa6..8dc7547c2377 100644
--- a/arch/powerpc/kernel/io.c
+++ b/arch/powerpc/kernel/io.c
@@ -161,7 +161,7 @@ void _memcpy_fromio(void *dest, const volatile void __iomem *src,
 		dest++;
 		n--;
 	}
-	while(n > 4) {
+	while(n >= 4) {
 		*((u32 *)dest) = *((volatile u32 *)vsrc);
 		eieio();
 		vsrc += 4;
@@ -190,7 +190,7 @@ void _memcpy_toio(volatile void __iomem *dest, const void *src, unsigned long n)
 		vdest++;
 		n--;
 	}
-	while(n > 4) {
+	while(n >= 4) {
 		*((volatile u32 *)vdest) = *((volatile u32 *)src);
 		src += 4;
 		vdest += 4;
diff --git a/arch/powerpc/platforms/52xx/Kconfig b/arch/powerpc/platforms/52xx/Kconfig
index 8b8e9560a315..47ea1be1481b 100644
--- a/arch/powerpc/platforms/52xx/Kconfig
+++ b/arch/powerpc/platforms/52xx/Kconfig
@@ -62,3 +62,8 @@ config PPC_MPC5200_GPIO
 	select GENERIC_GPIO
 	help
 	  Enable gpiolib support for mpc5200 based boards
+
+config PPC_MPC5200_LPBFIFO
+	tristate "MPC5200 LocalPlus bus FIFO driver"
+	depends on PPC_MPC52xx
+	select PPC_BESTCOMM_GEN_BD
diff --git a/arch/powerpc/platforms/52xx/Makefile b/arch/powerpc/platforms/52xx/Makefile
index bfd4f52cf3dd..2bc8cd0c5cfc 100644
--- a/arch/powerpc/platforms/52xx/Makefile
+++ b/arch/powerpc/platforms/52xx/Makefile
@@ -15,3 +15,4 @@ ifeq ($(CONFIG_PPC_LITE5200),y)
 endif
 
 obj-$(CONFIG_PPC_MPC5200_GPIO)	+= mpc52xx_gpio.o
+obj-$(CONFIG_PPC_MPC5200_LPBFIFO)	+= mpc52xx_lpbfifo.o
diff --git a/arch/powerpc/platforms/52xx/mpc52xx_gpt.c b/arch/powerpc/platforms/52xx/mpc52xx_gpt.c
index bfbcd418e690..2c3fa13571ce 100644
--- a/arch/powerpc/platforms/52xx/mpc52xx_gpt.c
+++ b/arch/powerpc/platforms/52xx/mpc52xx_gpt.c
@@ -46,13 +46,17 @@
  * the output mode.  This driver does not change the output mode setting.
  */
 
+#include <linux/device.h>
 #include <linux/irq.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
 #include <linux/of_gpio.h>
 #include <linux/kernel.h>
+#include <asm/div64.h>
 #include <asm/mpc52xx.h>
 
 MODULE_DESCRIPTION("Freescale MPC52xx gpt driver");
@@ -68,16 +72,21 @@ MODULE_LICENSE("GPL");
  * @irqhost: Pointer to irq_host instance; used when IRQ mode is supported
  */
 struct mpc52xx_gpt_priv {
+	struct list_head list;		/* List of all GPT devices */
 	struct device *dev;
 	struct mpc52xx_gpt __iomem *regs;
 	spinlock_t lock;
 	struct irq_host *irqhost;
+	u32 ipb_freq;
 
 #if defined(CONFIG_GPIOLIB)
 	struct of_gpio_chip of_gc;
 #endif
 };
 
+LIST_HEAD(mpc52xx_gpt_list);
+DEFINE_MUTEX(mpc52xx_gpt_list_mutex);
+
 #define MPC52xx_GPT_MODE_MS_MASK	(0x07)
 #define MPC52xx_GPT_MODE_MS_IC		(0x01)
 #define MPC52xx_GPT_MODE_MS_OC		(0x02)
@@ -88,6 +97,9 @@ struct mpc52xx_gpt_priv {
 #define MPC52xx_GPT_MODE_GPIO_OUT_LOW	(0x20)
 #define MPC52xx_GPT_MODE_GPIO_OUT_HIGH	(0x30)
 
+#define MPC52xx_GPT_MODE_COUNTER_ENABLE	(0x1000)
+#define MPC52xx_GPT_MODE_CONTINUOUS	(0x0400)
+#define MPC52xx_GPT_MODE_OPEN_DRAIN	(0x0200)
 #define MPC52xx_GPT_MODE_IRQ_EN		(0x0100)
 
 #define MPC52xx_GPT_MODE_ICT_MASK	(0x030000)
@@ -190,7 +202,7 @@ static int mpc52xx_gpt_irq_xlate(struct irq_host *h, struct device_node *ct,
 
 	dev_dbg(gpt->dev, "%s: flags=%i\n", __func__, intspec[0]);
 
-	if ((intsize < 1) || (intspec[0] < 1) || (intspec[0] > 3)) {
+	if ((intsize < 1) || (intspec[0] > 3)) {
 		dev_err(gpt->dev, "bad irq specifier in %s\n", ct->full_name);
 		return -EINVAL;
 	}
@@ -211,13 +223,11 @@ mpc52xx_gpt_irq_setup(struct mpc52xx_gpt_priv *gpt, struct device_node *node)
 {
 	int cascade_virq;
 	unsigned long flags;
-
-	/* Only setup cascaded IRQ if device tree claims the GPT is
-	 * an interrupt controller */
-	if (!of_find_property(node, "interrupt-controller", NULL))
-		return;
+	u32 mode;
 
 	cascade_virq = irq_of_parse_and_map(node, 0);
+	if (!cascade_virq)
+		return;
 
 	gpt->irqhost = irq_alloc_host(node, IRQ_HOST_MAP_LINEAR, 1,
 				      &mpc52xx_gpt_irq_ops, -1);
@@ -227,14 +237,16 @@ mpc52xx_gpt_irq_setup(struct mpc52xx_gpt_priv *gpt, struct device_node *node)
 	}
 
 	gpt->irqhost->host_data = gpt;
-
 	set_irq_data(cascade_virq, gpt);
 	set_irq_chained_handler(cascade_virq, mpc52xx_gpt_irq_cascade);
 
-	/* Set to Input Capture mode */
+	/* If the GPT is currently disabled, then change it to be in Input
+	 * Capture mode.  If the mode is non-zero, then the pin could be
+	 * already in use for something. */
 	spin_lock_irqsave(&gpt->lock, flags);
-	clrsetbits_be32(&gpt->regs->mode, MPC52xx_GPT_MODE_MS_MASK,
-			MPC52xx_GPT_MODE_MS_IC);
+	mode = in_be32(&gpt->regs->mode);
+	if ((mode & MPC52xx_GPT_MODE_MS_MASK) == 0)
+		out_be32(&gpt->regs->mode, mode | MPC52xx_GPT_MODE_MS_IC);
 	spin_unlock_irqrestore(&gpt->lock, flags);
 
 	dev_dbg(gpt->dev, "%s() complete. virq=%i\n", __func__, cascade_virq);
@@ -335,6 +347,102 @@ static void
 mpc52xx_gpt_gpio_setup(struct mpc52xx_gpt_priv *p, struct device_node *np) { }
 #endif /* defined(CONFIG_GPIOLIB) */
 
+/***********************************************************************
+ * Timer API
+ */
+
+/**
+ * mpc52xx_gpt_from_irq - Return the GPT device associated with an IRQ number
+ * @irq: irq of timer.
+ */
+struct mpc52xx_gpt_priv *mpc52xx_gpt_from_irq(int irq)
+{
+	struct mpc52xx_gpt_priv *gpt;
+	struct list_head *pos;
+
+	/* Iterate over the list of timers looking for a matching device */
+	mutex_lock(&mpc52xx_gpt_list_mutex);
+	list_for_each(pos, &mpc52xx_gpt_list) {
+		gpt = container_of(pos, struct mpc52xx_gpt_priv, list);
+		if (gpt->irqhost && irq == irq_linear_revmap(gpt->irqhost, 0)) {
+			mutex_unlock(&mpc52xx_gpt_list_mutex);
+			return gpt;
+		}
+	}
+	mutex_unlock(&mpc52xx_gpt_list_mutex);
+
+	return NULL;
+}
+EXPORT_SYMBOL(mpc52xx_gpt_from_irq);
+
+/**
+ * mpc52xx_gpt_start_timer - Set and enable the GPT timer
+ * @gpt: Pointer to gpt private data structure
+ * @period: period of timer
+ * @continuous: set to 1 to make timer continuous free running
+ *
+ * An interrupt will be generated every time the timer fires
+ */
+int mpc52xx_gpt_start_timer(struct mpc52xx_gpt_priv *gpt, int period,
+                            int continuous)
+{
+	u32 clear, set;
+	u64 clocks;
+	u32 prescale;
+	unsigned long flags;
+
+	clear = MPC52xx_GPT_MODE_MS_MASK | MPC52xx_GPT_MODE_CONTINUOUS;
+	set = MPC52xx_GPT_MODE_MS_GPIO | MPC52xx_GPT_MODE_COUNTER_ENABLE;
+	if (continuous)
+		set |= MPC52xx_GPT_MODE_CONTINUOUS;
+
+	/* Determine the number of clocks in the requested period.  64 bit
+	 * arithmatic is done here to preserve the precision until the value
+	 * is scaled back down into the u32 range.  Period is in 'ns', bus
+	 * frequency is in Hz. */
+	clocks = (u64)period * (u64)gpt->ipb_freq;
+	do_div(clocks, 1000000000); /* Scale it down to ns range */
+
+	/* This device cannot handle a clock count greater than 32 bits */
+	if (clocks > 0xffffffff)
+		return -EINVAL;
+
+	/* Calculate the prescaler and count values from the clocks value.
+	 * 'clocks' is the number of clock ticks in the period.  The timer
+	 * has 16 bit precision and a 16 bit prescaler.  Prescaler is
+	 * calculated by integer dividing the clocks by 0x10000 (shifting
+	 * down 16 bits) to obtain the smallest possible divisor for clocks
+	 * to get a 16 bit count value.
+	 *
+	 * Note: the prescale register is '1' based, not '0' based.  ie. a
+	 * value of '1' means divide the clock by one.  0xffff divides the
+	 * clock by 0xffff.  '0x0000' does not divide by zero, but wraps
+	 * around and divides by 0x10000.  That is why prescale must be
+	 * a u32 variable, not a u16, for this calculation. */
+	prescale = (clocks >> 16) + 1;
+	do_div(clocks, prescale);
+	if (clocks > 0xffff) {
+		pr_err("calculation error; prescale:%x clocks:%llx\n",
+		       prescale, clocks);
+		return -EINVAL;
+	}
+
+	/* Set and enable the timer */
+	spin_lock_irqsave(&gpt->lock, flags);
+	out_be32(&gpt->regs->count, prescale << 16 | clocks);
+	clrsetbits_be32(&gpt->regs->mode, clear, set);
+	spin_unlock_irqrestore(&gpt->lock, flags);
+
+	return 0;
+}
+EXPORT_SYMBOL(mpc52xx_gpt_start_timer);
+
+void mpc52xx_gpt_stop_timer(struct mpc52xx_gpt_priv *gpt)
+{
+	clrbits32(&gpt->regs->mode, MPC52xx_GPT_MODE_COUNTER_ENABLE);
+}
+EXPORT_SYMBOL(mpc52xx_gpt_stop_timer);
+
 /* ---------------------------------------------------------------------
  * of_platform bus binding code
  */
@@ -349,6 +457,7 @@ static int __devinit mpc52xx_gpt_probe(struct of_device *ofdev,
 
 	spin_lock_init(&gpt->lock);
 	gpt->dev = &ofdev->dev;
+	gpt->ipb_freq = mpc5xxx_get_bus_frequency(ofdev->node);
 	gpt->regs = of_iomap(ofdev->node, 0);
 	if (!gpt->regs) {
 		kfree(gpt);
@@ -360,6 +469,10 @@ static int __devinit mpc52xx_gpt_probe(struct of_device *ofdev,
 	mpc52xx_gpt_gpio_setup(gpt, ofdev->node);
 	mpc52xx_gpt_irq_setup(gpt, ofdev->node);
 
+	mutex_lock(&mpc52xx_gpt_list_mutex);
+	list_add(&gpt->list, &mpc52xx_gpt_list);
+	mutex_unlock(&mpc52xx_gpt_list_mutex);
+
 	return 0;
 }
 
diff --git a/arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c b/arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c
new file mode 100644
index 000000000000..929d017535a3
--- /dev/null
+++ b/arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c
@@ -0,0 +1,560 @@
+/*
+ * LocalPlus Bus FIFO driver for the Freescale MPC52xx.
+ *
+ * Copyright (C) 2009 Secret Lab Technologies Ltd.
+ *
+ * This file is released under the GPLv2
+ *
+ * Todo:
+ * - Add support for multiple requests to be queued.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/spinlock.h>
+#include <asm/io.h>
+#include <asm/prom.h>
+#include <asm/mpc52xx.h>
+#include <asm/time.h>
+
+#include <sysdev/bestcomm/bestcomm.h>
+#include <sysdev/bestcomm/bestcomm_priv.h>
+#include <sysdev/bestcomm/gen_bd.h>
+
+MODULE_AUTHOR("Grant Likely <grant.likely@secretlab.ca>");
+MODULE_DESCRIPTION("MPC5200 LocalPlus FIFO device driver");
+MODULE_LICENSE("GPL");
+
+#define LPBFIFO_REG_PACKET_SIZE		(0x00)
+#define LPBFIFO_REG_START_ADDRESS	(0x04)
+#define LPBFIFO_REG_CONTROL		(0x08)
+#define LPBFIFO_REG_ENABLE		(0x0C)
+#define LPBFIFO_REG_BYTES_DONE_STATUS	(0x14)
+#define LPBFIFO_REG_FIFO_DATA		(0x40)
+#define LPBFIFO_REG_FIFO_STATUS		(0x44)
+#define LPBFIFO_REG_FIFO_CONTROL	(0x48)
+#define LPBFIFO_REG_FIFO_ALARM		(0x4C)
+
+struct mpc52xx_lpbfifo {
+	struct device *dev;
+	phys_addr_t regs_phys;
+	void __iomem *regs;
+	int irq;
+	spinlock_t lock;
+
+	struct bcom_task *bcom_tx_task;
+	struct bcom_task *bcom_rx_task;
+	struct bcom_task *bcom_cur_task;
+
+	/* Current state data */
+	struct mpc52xx_lpbfifo_request *req;
+	int dma_irqs_enabled;
+};
+
+/* The MPC5200 has only one fifo, so only need one instance structure */
+static struct mpc52xx_lpbfifo lpbfifo;
+
+/**
+ * mpc52xx_lpbfifo_kick - Trigger the next block of data to be transfered
+ */
+static void mpc52xx_lpbfifo_kick(struct mpc52xx_lpbfifo_request *req)
+{
+	size_t transfer_size = req->size - req->pos;
+	struct bcom_bd *bd;
+	void __iomem *reg;
+	u32 *data;
+	int i;
+	int bit_fields;
+	int dma = !(req->flags & MPC52XX_LPBFIFO_FLAG_NO_DMA);
+	int write = req->flags & MPC52XX_LPBFIFO_FLAG_WRITE;
+	int poll_dma = req->flags & MPC52XX_LPBFIFO_FLAG_POLL_DMA;
+
+	/* Set and clear the reset bits; is good practice in User Manual */
+	out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, 0x01010000);
+
+	/* set master enable bit */
+	out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, 0x00000001);
+	if (!dma) {
+		/* While the FIFO can be setup for transfer sizes as large as
+		 * 16M-1, the FIFO itself is only 512 bytes deep and it does
+		 * not generate interrupts for FIFO full events (only transfer
+		 * complete will raise an IRQ).  Therefore when not using
+		 * Bestcomm to drive the FIFO it needs to either be polled, or
+		 * transfers need to constrained to the size of the fifo.
+		 *
+		 * This driver restricts the size of the transfer
+		 */
+		if (transfer_size > 512)
+			transfer_size = 512;
+
+		/* Load the FIFO with data */
+		if (write) {
+			reg = lpbfifo.regs + LPBFIFO_REG_FIFO_DATA;
+			data = req->data + req->pos;
+			for (i = 0; i < transfer_size; i += 4)
+				out_be32(reg, *data++);
+		}
+
+		/* Unmask both error and completion irqs */
+		out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, 0x00000301);
+	} else {
+		/* Choose the correct direction
+		 *
+		 * Configure the watermarks so DMA will always complete correctly.
+		 * It may be worth experimenting with the ALARM value to see if
+		 * there is a performance impacit.  However, if it is wrong there
+		 * is a risk of DMA not transferring the last chunk of data
+		 */
+		if (write) {
+			out_be32(lpbfifo.regs + LPBFIFO_REG_FIFO_ALARM, 0x1e4);
+			out_8(lpbfifo.regs + LPBFIFO_REG_FIFO_CONTROL, 7);
+			lpbfifo.bcom_cur_task = lpbfifo.bcom_tx_task;
+		} else {
+			out_be32(lpbfifo.regs + LPBFIFO_REG_FIFO_ALARM, 0x1ff);
+			out_8(lpbfifo.regs + LPBFIFO_REG_FIFO_CONTROL, 0);
+			lpbfifo.bcom_cur_task = lpbfifo.bcom_rx_task;
+
+			if (poll_dma) {
+				if (lpbfifo.dma_irqs_enabled) {
+					disable_irq(bcom_get_task_irq(lpbfifo.bcom_rx_task));
+					lpbfifo.dma_irqs_enabled = 0;
+				}
+			} else {
+				if (!lpbfifo.dma_irqs_enabled) {
+					enable_irq(bcom_get_task_irq(lpbfifo.bcom_rx_task));
+					lpbfifo.dma_irqs_enabled = 1;
+				}
+			}
+		}
+
+		bd = bcom_prepare_next_buffer(lpbfifo.bcom_cur_task);
+		bd->status = transfer_size;
+		if (!write) {
+			/*
+			 * In the DMA read case, the DMA doesn't complete,
+			 * possibly due to incorrect watermarks in the ALARM
+			 * and CONTROL regs. For now instead of trying to
+			 * determine the right watermarks that will make this
+			 * work, just increase the number of bytes the FIFO is
+			 * expecting.
+			 *
+			 * When submitting another operation, the FIFO will get
+			 * reset, so the condition of the FIFO waiting for a
+			 * non-existent 4 bytes will get cleared.
+			 */
+			transfer_size += 4; /* BLECH! */
+		}
+		bd->data[0] = req->data_phys + req->pos;
+		bcom_submit_next_buffer(lpbfifo.bcom_cur_task, NULL);
+
+		/* error irq & master enabled bit */
+		bit_fields = 0x00000201;
+
+		/* Unmask irqs */
+		if (write && (!poll_dma))
+			bit_fields |= 0x00000100; /* completion irq too */
+		out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, bit_fields);
+	}
+
+	/* Set transfer size, width, chip select and READ mode */
+	out_be32(lpbfifo.regs + LPBFIFO_REG_START_ADDRESS,
+		 req->offset + req->pos);
+	out_be32(lpbfifo.regs + LPBFIFO_REG_PACKET_SIZE, transfer_size);
+
+	bit_fields = req->cs << 24 | 0x000008;
+	if (!write)
+		bit_fields |= 0x010000; /* read mode */
+	out_be32(lpbfifo.regs + LPBFIFO_REG_CONTROL, bit_fields);
+
+	/* Kick it off */
+	out_8(lpbfifo.regs + LPBFIFO_REG_PACKET_SIZE, 0x01);
+	if (dma)
+		bcom_enable(lpbfifo.bcom_cur_task);
+}
+
+/**
+ * mpc52xx_lpbfifo_irq - IRQ handler for LPB FIFO
+ *
+ * On transmit, the dma completion irq triggers before the fifo completion
+ * triggers.  Handle the dma completion here instead of the LPB FIFO Bestcomm
+ * task completion irq becuase everyting is not really done until the LPB FIFO
+ * completion irq triggers.
+ *
+ * In other words:
+ * For DMA, on receive, the "Fat Lady" is the bestcom completion irq. on
+ * transmit, the fifo completion irq is the "Fat Lady". The opera (or in this
+ * case the DMA/FIFO operation) is not finished until the "Fat Lady" sings.
+ *
+ * Reasons for entering this routine:
+ * 1) PIO mode rx and tx completion irq
+ * 2) DMA interrupt mode tx completion irq
+ * 3) DMA polled mode tx
+ *
+ * Exit conditions:
+ * 1) Transfer aborted
+ * 2) FIFO complete without DMA; more data to do
+ * 3) FIFO complete without DMA; all data transfered
+ * 4) FIFO complete using DMA
+ *
+ * Condition 1 can occur regardless of whether or not DMA is used.
+ * It requires executing the callback to report the error and exiting
+ * immediately.
+ *
+ * Condition 2 requires programming the FIFO with the next block of data
+ *
+ * Condition 3 requires executing the callback to report completion
+ *
+ * Condition 4 means the same as 3, except that we also retrieve the bcom
+ * buffer so DMA doesn't get clogged up.
+ *
+ * To make things trickier, the spinlock must be dropped before
+ * executing the callback, otherwise we could end up with a deadlock
+ * or nested spinlock condition.  The out path is non-trivial, so
+ * extra fiddling is done to make sure all paths lead to the same
+ * outbound code.
+ */
+static irqreturn_t mpc52xx_lpbfifo_irq(int irq, void *dev_id)
+{
+	struct mpc52xx_lpbfifo_request *req;
+	u32 status = in_8(lpbfifo.regs + LPBFIFO_REG_BYTES_DONE_STATUS);
+	void __iomem *reg;
+	u32 *data;
+	int count, i;
+	int do_callback = 0;
+	u32 ts;
+	unsigned long flags;
+	int dma, write, poll_dma;
+
+	spin_lock_irqsave(&lpbfifo.lock, flags);
+	ts = get_tbl();
+
+	req = lpbfifo.req;
+	if (!req) {
+		spin_unlock_irqrestore(&lpbfifo.lock, flags);
+		pr_err("bogus LPBFIFO IRQ\n");
+		return IRQ_HANDLED;
+	}
+
+	dma = !(req->flags & MPC52XX_LPBFIFO_FLAG_NO_DMA);
+	write = req->flags & MPC52XX_LPBFIFO_FLAG_WRITE;
+	poll_dma = req->flags & MPC52XX_LPBFIFO_FLAG_POLL_DMA;
+
+	if (dma && !write) {
+		spin_unlock_irqrestore(&lpbfifo.lock, flags);
+		pr_err("bogus LPBFIFO IRQ (dma and not writting)\n");
+		return IRQ_HANDLED;
+	}
+
+	if ((status & 0x01) == 0) {
+		goto out;
+	}
+
+	/* check abort bit */
+	if (status & 0x10) {
+		out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, 0x01010000);
+		do_callback = 1;
+		goto out;
+	}
+
+	/* Read result from hardware */
+	count = in_be32(lpbfifo.regs + LPBFIFO_REG_BYTES_DONE_STATUS);
+	count &= 0x00ffffff;
+
+	if (!dma && !write) {
+		/* copy the data out of the FIFO */
+		reg = lpbfifo.regs + LPBFIFO_REG_FIFO_DATA;
+		data = req->data + req->pos;
+		for (i = 0; i < count; i += 4)
+			*data++ = in_be32(reg);
+	}
+
+	/* Update transfer position and count */
+	req->pos += count;
+
+	/* Decide what to do next */
+	if (req->size - req->pos)
+		mpc52xx_lpbfifo_kick(req); /* more work to do */
+	else
+		do_callback = 1;
+
+ out:
+	/* Clear the IRQ */
+	out_8(lpbfifo.regs + LPBFIFO_REG_BYTES_DONE_STATUS, 0x01);
+
+	if (dma && (status & 0x11)) {
+		/*
+		 * Count the DMA as complete only when the FIFO completion
+		 * status or abort bits are set.
+		 *
+		 * (status & 0x01) should always be the case except sometimes
+		 * when using polled DMA.
+		 *
+		 * (status & 0x10) {transfer aborted}: This case needs more
+		 * testing.
+		 */
+		bcom_retrieve_buffer(lpbfifo.bcom_cur_task, &status, NULL);
+	}
+	req->last_byte = ((u8 *)req->data)[req->size - 1];
+
+	/* When the do_callback flag is set; it means the transfer is finished
+	 * so set the FIFO as idle */
+	if (do_callback)
+		lpbfifo.req = NULL;
+
+	if (irq != 0) /* don't increment on polled case */
+		req->irq_count++;
+
+	req->irq_ticks += get_tbl() - ts;
+	spin_unlock_irqrestore(&lpbfifo.lock, flags);
+
+	/* Spinlock is released; it is now safe to call the callback */
+	if (do_callback && req->callback)
+		req->callback(req);
+
+	return IRQ_HANDLED;
+}
+
+/**
+ * mpc52xx_lpbfifo_bcom_irq - IRQ handler for LPB FIFO Bestcomm task
+ *
+ * Only used when receiving data.
+ */
+static irqreturn_t mpc52xx_lpbfifo_bcom_irq(int irq, void *dev_id)
+{
+	struct mpc52xx_lpbfifo_request *req;
+	unsigned long flags;
+	u32 status;
+	u32 ts;
+
+	spin_lock_irqsave(&lpbfifo.lock, flags);
+	ts = get_tbl();
+
+	req = lpbfifo.req;
+	if (!req || (req->flags & MPC52XX_LPBFIFO_FLAG_NO_DMA)) {
+		spin_unlock_irqrestore(&lpbfifo.lock, flags);
+		return IRQ_HANDLED;
+	}
+
+	if (irq != 0) /* don't increment on polled case */
+		req->irq_count++;
+
+	if (!bcom_buffer_done(lpbfifo.bcom_cur_task)) {
+		spin_unlock_irqrestore(&lpbfifo.lock, flags);
+
+		req->buffer_not_done_cnt++;
+		if ((req->buffer_not_done_cnt % 1000) == 0)
+			pr_err("transfer stalled\n");
+
+		return IRQ_HANDLED;
+	}
+
+	bcom_retrieve_buffer(lpbfifo.bcom_cur_task, &status, NULL);
+
+	req->last_byte = ((u8 *)req->data)[req->size - 1];
+
+	req->pos = status & 0x00ffffff;
+
+	/* Mark the FIFO as idle */
+	lpbfifo.req = NULL;
+
+	/* Release the lock before calling out to the callback. */
+	req->irq_ticks += get_tbl() - ts;
+	spin_unlock_irqrestore(&lpbfifo.lock, flags);
+
+	if (req->callback)
+		req->callback(req);
+
+	return IRQ_HANDLED;
+}
+
+/**
+ * mpc52xx_lpbfifo_bcom_poll - Poll for DMA completion
+ */
+void mpc52xx_lpbfifo_poll(void)
+{
+	struct mpc52xx_lpbfifo_request *req = lpbfifo.req;
+	int dma = !(req->flags & MPC52XX_LPBFIFO_FLAG_NO_DMA);
+	int write = req->flags & MPC52XX_LPBFIFO_FLAG_WRITE;
+
+	/*
+	 * For more information, see comments on the "Fat Lady" 
+	 */
+	if (dma && write)
+		mpc52xx_lpbfifo_irq(0, NULL);
+	else 
+		mpc52xx_lpbfifo_bcom_irq(0, NULL);
+}
+EXPORT_SYMBOL(mpc52xx_lpbfifo_poll);
+
+/**
+ * mpc52xx_lpbfifo_submit - Submit an LPB FIFO transfer request.
+ * @req: Pointer to request structure
+ */
+int mpc52xx_lpbfifo_submit(struct mpc52xx_lpbfifo_request *req)
+{
+	unsigned long flags;
+
+	if (!lpbfifo.regs)
+		return -ENODEV;
+
+	spin_lock_irqsave(&lpbfifo.lock, flags);
+
+	/* If the req pointer is already set, then a transfer is in progress */
+	if (lpbfifo.req) {
+		spin_unlock_irqrestore(&lpbfifo.lock, flags);
+		return -EBUSY;
+	}
+
+	/* Setup the transfer */
+	lpbfifo.req = req;
+	req->irq_count = 0;
+	req->irq_ticks = 0;
+	req->buffer_not_done_cnt = 0;
+	req->pos = 0;
+
+	mpc52xx_lpbfifo_kick(req);
+	spin_unlock_irqrestore(&lpbfifo.lock, flags);
+	return 0;
+}
+EXPORT_SYMBOL(mpc52xx_lpbfifo_submit);
+
+void mpc52xx_lpbfifo_abort(struct mpc52xx_lpbfifo_request *req)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&lpbfifo.lock, flags);
+	if (lpbfifo.req == req) {
+		/* Put it into reset and clear the state */
+		bcom_gen_bd_rx_reset(lpbfifo.bcom_rx_task);
+		bcom_gen_bd_tx_reset(lpbfifo.bcom_tx_task);
+		out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, 0x01010000);
+		lpbfifo.req = NULL;
+	}
+	spin_unlock_irqrestore(&lpbfifo.lock, flags);
+}
+EXPORT_SYMBOL(mpc52xx_lpbfifo_abort);
+
+static int __devinit
+mpc52xx_lpbfifo_probe(struct of_device *op, const struct of_device_id *match)
+{
+	struct resource res;
+	int rc = -ENOMEM;
+
+	if (lpbfifo.dev != NULL)
+		return -ENOSPC;
+
+	lpbfifo.irq = irq_of_parse_and_map(op->node, 0);
+	if (!lpbfifo.irq)
+		return -ENODEV;
+
+	if (of_address_to_resource(op->node, 0, &res))
+		return -ENODEV;
+	lpbfifo.regs_phys = res.start;
+	lpbfifo.regs = of_iomap(op->node, 0);
+	if (!lpbfifo.regs)
+		return -ENOMEM;
+
+	spin_lock_init(&lpbfifo.lock);
+
+	/* Put FIFO into reset */
+	out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, 0x01010000);
+
+	/* Register the interrupt handler */
+	rc = request_irq(lpbfifo.irq, mpc52xx_lpbfifo_irq, 0,
+			 "mpc52xx-lpbfifo", &lpbfifo);
+	if (rc)
+		goto err_irq;
+
+	/* Request the Bestcomm receive (fifo --> memory) task and IRQ */
+	lpbfifo.bcom_rx_task =
+		bcom_gen_bd_rx_init(2, res.start + LPBFIFO_REG_FIFO_DATA,
+				    BCOM_INITIATOR_SCLPC, BCOM_IPR_SCLPC,
+				    16*1024*1024);
+	if (!lpbfifo.bcom_rx_task)
+		goto err_bcom_rx;
+
+	rc = request_irq(bcom_get_task_irq(lpbfifo.bcom_rx_task),
+			 mpc52xx_lpbfifo_bcom_irq, 0,
+			 "mpc52xx-lpbfifo-rx", &lpbfifo);
+	if (rc)
+		goto err_bcom_rx_irq;
+
+	/* Request the Bestcomm transmit (memory --> fifo) task and IRQ */
+	lpbfifo.bcom_tx_task =
+		bcom_gen_bd_tx_init(2, res.start + LPBFIFO_REG_FIFO_DATA,
+				    BCOM_INITIATOR_SCLPC, BCOM_IPR_SCLPC);
+	if (!lpbfifo.bcom_tx_task)
+		goto err_bcom_tx;
+
+	lpbfifo.dev = &op->dev;
+	return 0;
+
+ err_bcom_tx:
+	free_irq(bcom_get_task_irq(lpbfifo.bcom_rx_task), &lpbfifo);
+ err_bcom_rx_irq:
+	bcom_gen_bd_rx_release(lpbfifo.bcom_rx_task);
+ err_bcom_rx:
+ err_irq:
+	iounmap(lpbfifo.regs);
+	lpbfifo.regs = NULL;
+
+	dev_err(&op->dev, "mpc52xx_lpbfifo_probe() failed\n");
+	return -ENODEV;
+}
+
+
+static int __devexit mpc52xx_lpbfifo_remove(struct of_device *op)
+{
+	if (lpbfifo.dev != &op->dev)
+		return 0;
+
+	/* Put FIFO in reset */
+	out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, 0x01010000);
+
+	/* Release the bestcomm transmit task */
+	free_irq(bcom_get_task_irq(lpbfifo.bcom_tx_task), &lpbfifo);
+	bcom_gen_bd_tx_release(lpbfifo.bcom_tx_task);
+	
+	/* Release the bestcomm receive task */
+	free_irq(bcom_get_task_irq(lpbfifo.bcom_rx_task), &lpbfifo);
+	bcom_gen_bd_rx_release(lpbfifo.bcom_rx_task);
+
+	free_irq(lpbfifo.irq, &lpbfifo);
+	iounmap(lpbfifo.regs);
+	lpbfifo.regs = NULL;
+	lpbfifo.dev = NULL;
+
+	return 0;
+}
+
+static struct of_device_id mpc52xx_lpbfifo_match[] __devinitconst = {
+	{ .compatible = "fsl,mpc5200-lpbfifo", },
+	{},
+};
+
+static struct of_platform_driver mpc52xx_lpbfifo_driver = {
+	.owner = THIS_MODULE,
+	.name = "mpc52xx-lpbfifo",
+	.match_table = mpc52xx_lpbfifo_match,
+	.probe = mpc52xx_lpbfifo_probe,
+	.remove = __devexit_p(mpc52xx_lpbfifo_remove),
+};
+
+/***********************************************************************
+ * Module init/exit
+ */
+static int __init mpc52xx_lpbfifo_init(void)
+{
+	pr_debug("Registering LocalPlus bus FIFO driver\n");
+	return of_register_platform_driver(&mpc52xx_lpbfifo_driver);
+}
+module_init(mpc52xx_lpbfifo_init);
+
+static void __exit mpc52xx_lpbfifo_exit(void)
+{
+	pr_debug("Unregistering LocalPlus bus FIFO driver\n");
+	of_unregister_platform_driver(&mpc52xx_lpbfifo_driver);
+}
+module_exit(mpc52xx_lpbfifo_exit);