powerpc/5200: add LocalPlus bus FIFO device driver
authorJohn Bonesio <bones@secretlab.ca>
Tue, 29 Sep 2009 10:43:42 +0000 (10:43 +0000)
committerGrant Likely <grant.likely@secretlab.ca>
Wed, 4 Nov 2009 23:42:47 +0000 (16:42 -0700)
This is a driver for the FIFO device on the LocalPlus bus on an mpc5200 system.
The driver supports programmed I/O through the FIFO as well as setting up DMA
via the BestComm engine through the FIFO.

Signed-off-by: John Bonesio <bones@secretlab.ca>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
arch/powerpc/include/asm/mpc52xx.h
arch/powerpc/platforms/52xx/Kconfig
arch/powerpc/platforms/52xx/Makefile
arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c [new file with mode: 0644]

index 671685011a239e5c84c284f31dcbce9ee31d93cb..707ab7590cfb9d3e8ffe06aa40375283a471eecd 100644 (file)
@@ -283,6 +283,45 @@ 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);
index 8b8e9560a315ed51127625b8544edc8a2f24b667..47ea1be1481bdeec198dfe09f9194e0c9201e47d 100644 (file)
@@ -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
index bfd4f52cf3dd785a3827e78bffcb7fcc6a168f5e..2bc8cd0c5cfc5b0edfaa2581ddcaead1e168374e 100644 (file)
@@ -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_lpbfifo.c b/arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c
new file mode 100644 (file)
index 0000000..929d017
--- /dev/null
@@ -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);