Subject: Re: [PATCH] powerpc/5200: add LocalPlus bus FIFO device driver

From: Grant Likely <[email-masked]>
Date: Tue, 29 Sep 2009 20:25:09 -0600

On Tue, Sep 29, 2009 at 2:43 PM, John Bonesio <[email-masked]> wrote:
> 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: Grant Likely <[email-masked]>
> Signed-off-by: John Bonesio <[email-masked]>

Let me know if anyone has comments on this.  Since it is a new driver,
I'll probably try to merge it for 2.6.32 in the next week or so even
though the merge window has closed.

Cheers,
g.

> ---
> This driver was originally written by Grant Likely. I have updated it so that
> transmitting data (as opposed to receiving data) works better. The driver has
> been tested for all 6 transfer modes:
>        PIO mode (rx and tx)
>        DMA polled mode (rx and tx)
>        DMA interrupt mode (rx and tx)
>
> - John
>
>  arch/powerpc/include/asm/mpc52xx.h            |   39 ++
>  arch/powerpc/platforms/52xx/Kconfig           |    5
>  arch/powerpc/platforms/52xx/Makefile          |    1
>  arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c |  560 +++++++++++++++++++++++++
>  4 files changed, 605 insertions(+), 0 deletions(-)
>  create mode 100644 arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c
>
> diff --git a/arch/powerpc/include/asm/mpc52xx.h b/arch/powerpc/include/asm/mpc52xx.h
> index 8273357..819a0be 100644
> --- a/arch/powerpc/include/asm/mpc52xx.h
> +++ b/arch/powerpc/include/asm/mpc52xx.h
> @@ -282,6 +282,45 @@ 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);
> diff --git a/arch/powerpc/platforms/52xx/Kconfig b/arch/powerpc/platforms/52xx/Kconfig
> index 696a5ee..ea00b3d 100644
> --- a/arch/powerpc/platforms/52xx/Kconfig
> +++ b/arch/powerpc/platforms/52xx/Kconfig
> @@ -51,3 +51,8 @@ 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 d6ade3d..8df23af 100644
> --- a/arch/powerpc/platforms/52xx/Makefile
> +++ b/arch/powerpc/platforms/52xx/Makefile
> @@ -14,3 +14,4 @@ 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
> index 0000000..929d017
> --- /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 <[email-masked]>");
> +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);
>
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>

-- 
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.