/*
 * drivers/media/video/omap24xxcam.c
 *
 * OMAP 2 camera block driver.
 *
 * Copyright (C) 2004 MontaVista Software, Inc.
 * Copyright (C) 2004 Texas Instruments.
 * Copyright (C) 2007-2008 Nokia Corporation.
 *
 * Contact: Sakari Ailus <sakari.ailus@nokia.com>
 *
 * Based on code from Andy Lowe <source@mvista.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 */

#include <linux/delay.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/videodev2.h>
#include <linux/pci.h>          /* needed for videobufs */
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/module.h>

#include <media/v4l2-common.h>
#include <media/v4l2-ioctl.h>

#include "omap24xxcam.h"

#define OMAP24XXCAM_VERSION "0.0.1"

#define RESET_TIMEOUT_NS 10000

static void omap24xxcam_reset(struct omap24xxcam_device *cam);
static int omap24xxcam_sensor_if_enable(struct omap24xxcam_device *cam);
static void omap24xxcam_device_unregister(struct v4l2_int_device *s);
static int omap24xxcam_remove(struct platform_device *pdev);

/* module parameters */
static int video_nr = -1;       /* video device minor (-1 ==> auto assign) */
/*
 * Maximum amount of memory to use for capture buffers.
 * Default is 4800KB, enough to double-buffer SXGA.
 */
static int capture_mem = 1280 * 960 * 2 * 2;

static struct v4l2_int_device omap24xxcam;

/*
 *
 * Clocks.
 *
 */

static void omap24xxcam_clock_put(struct omap24xxcam_device *cam)
{
        if (cam->ick != NULL && !IS_ERR(cam->ick))
                clk_put(cam->ick);
        if (cam->fck != NULL && !IS_ERR(cam->fck))
                clk_put(cam->fck);

        cam->ick = cam->fck = NULL;
}

static int omap24xxcam_clock_get(struct omap24xxcam_device *cam)
{
        int rval = 0;

        cam->fck = clk_get(cam->dev, "fck");
        if (IS_ERR(cam->fck)) {
                dev_err(cam->dev, "can't get camera fck");
                rval = PTR_ERR(cam->fck);
                omap24xxcam_clock_put(cam);
                return rval;
        }

        cam->ick = clk_get(cam->dev, "ick");
        if (IS_ERR(cam->ick)) {
                dev_err(cam->dev, "can't get camera ick");
                rval = PTR_ERR(cam->ick);
                omap24xxcam_clock_put(cam);
        }

        return rval;
}

static void omap24xxcam_clock_on(struct omap24xxcam_device *cam)
{
        clk_enable(cam->fck);
        clk_enable(cam->ick);
}

static void omap24xxcam_clock_off(struct omap24xxcam_device *cam)
{
        clk_disable(cam->fck);
        clk_disable(cam->ick);
}

/*
 *
 * Camera core
 *
 */

/*
 * Set xclk.
 *
 * To disable xclk, use value zero.
 */
static void omap24xxcam_core_xclk_set(const struct omap24xxcam_device *cam,
                                      u32 xclk)
{
        if (xclk) {
                u32 divisor = CAM_MCLK / xclk;

                if (divisor == 1)
                        omap24xxcam_reg_out(cam->mmio_base + CC_REG_OFFSET,
                                            CC_CTRL_XCLK,
                                            CC_CTRL_XCLK_DIV_BYPASS);
                else
                        omap24xxcam_reg_out(cam->mmio_base + CC_REG_OFFSET,
                                            CC_CTRL_XCLK, divisor);
        } else
                omap24xxcam_reg_out(cam->mmio_base + CC_REG_OFFSET,
                                    CC_CTRL_XCLK, CC_CTRL_XCLK_DIV_STABLE_LOW);
}

static void omap24xxcam_core_hwinit(const struct omap24xxcam_device *cam)
{
        /*
         * Setting the camera core AUTOIDLE bit causes problems with frame
         * synchronization, so we will clear the AUTOIDLE bit instead.
         */
        omap24xxcam_reg_out(cam->mmio_base + CC_REG_OFFSET, CC_SYSCONFIG,
                            CC_SYSCONFIG_AUTOIDLE);

        /* program the camera interface DMA packet size */
        omap24xxcam_reg_out(cam->mmio_base + CC_REG_OFFSET, CC_CTRL_DMA,
                            CC_CTRL_DMA_EN | (DMA_THRESHOLD / 4 - 1));

        /* enable camera core error interrupts */
        omap24xxcam_reg_out(cam->mmio_base + CC_REG_OFFSET, CC_IRQENABLE,
                            CC_IRQENABLE_FW_ERR_IRQ
                            | CC_IRQENABLE_FSC_ERR_IRQ
                            | CC_IRQENABLE_SSC_ERR_IRQ
                            | CC_IRQENABLE_FIFO_OF_IRQ);
}

/*
 * Enable the camera core.
 *
 * Data transfer to the camera DMA starts from next starting frame.
 */
static void omap24xxcam_core_enable(const struct omap24xxcam_device *cam)
{

        omap24xxcam_reg_out(cam->mmio_base + CC_REG_OFFSET, CC_CTRL,
                            cam->cc_ctrl);
}

/*
 * Disable camera core.
 *
 * The data transfer will be stopped immediately (CC_CTRL_CC_RST). The
 * core internal state machines will be reset. Use
 * CC_CTRL_CC_FRAME_TRIG instead if you want to transfer the current
 * frame completely.
 */
static void omap24xxcam_core_disable(const struct omap24xxcam_device *cam)
{
        omap24xxcam_reg_out(cam->mmio_base + CC_REG_OFFSET, CC_CTRL,
                            CC_CTRL_CC_RST);
}

/* Interrupt service routine for camera core interrupts. */
static void omap24xxcam_core_isr(struct omap24xxcam_device *cam)
{
        u32 cc_irqstatus;
        const u32 cc_irqstatus_err =
                CC_IRQSTATUS_FW_ERR_IRQ
                | CC_IRQSTATUS_FSC_ERR_IRQ
                | CC_IRQSTATUS_SSC_ERR_IRQ
                | CC_IRQSTATUS_FIFO_UF_IRQ
                | CC_IRQSTATUS_FIFO_OF_IRQ;

        cc_irqstatus = omap24xxcam_reg_in(cam->mmio_base + CC_REG_OFFSET,
                                          CC_IRQSTATUS);
        omap24xxcam_reg_out(cam->mmio_base + CC_REG_OFFSET, CC_IRQSTATUS,
                            cc_irqstatus);

        if (cc_irqstatus & cc_irqstatus_err
            && !atomic_read(&cam->in_reset)) {
                dev_dbg(cam->dev, "resetting camera, cc_irqstatus 0x%x\n",
                        cc_irqstatus);
                omap24xxcam_reset(cam);
        }
}

/*
 *
 * videobuf_buffer handling.
 *
 * Memory for mmapped videobuf_buffers is not allocated
 * conventionally, but by several kmalloc allocations and then
 * creating the scatterlist on our own. User-space buffers are handled
 * normally.
 *
 */

/*
 * Free the memory-mapped buffer memory allocated for a
 * videobuf_buffer and the associated scatterlist.
 */
static void omap24xxcam_vbq_free_mmap_buffer(struct videobuf_buffer *vb)
{
        struct videobuf_dmabuf *dma = videobuf_to_dma(vb);
        size_t alloc_size;
        struct page *page;
        int i;

        if (dma->sglist == NULL)
                return;

        i = dma->sglen;
        while (i) {
                i--;
                alloc_size = sg_dma_len(&dma->sglist[i]);
                page = sg_page(&dma->sglist[i]);
                do {
                        ClearPageReserved(page++);
                } while (alloc_size -= PAGE_SIZE);
                __free_pages(sg_page(&dma->sglist[i]),
                             get_order(sg_dma_len(&dma->sglist[i])));
        }

        kfree(dma->sglist);
        dma->sglist = NULL;
}

/* Release all memory related to the videobuf_queue. */
static void omap24xxcam_vbq_free_mmap_buffers(struct videobuf_queue *vbq)
{
        int i;

        mutex_lock(&vbq->vb_lock);

        for (i = 0; i < VIDEO_MAX_FRAME; i++) {
                if (NULL == vbq->bufs[i])
                        continue;
                if (V4L2_MEMORY_MMAP != vbq->bufs[i]->memory)
                        continue;
                vbq->ops->buf_release(vbq, vbq->bufs[i]);
                omap24xxcam_vbq_free_mmap_buffer(vbq->bufs[i]);
                kfree(vbq->bufs[i]);
                vbq->bufs[i] = NULL;
        }

        mutex_unlock(&vbq->vb_lock);

        videobuf_mmap_free(vbq);
}

/*
 * Allocate physically as contiguous as possible buffer for video
 * frame and allocate and build DMA scatter-gather list for it.
 */
static int omap24xxcam_vbq_alloc_mmap_buffer(struct videobuf_buffer *vb)
{
        unsigned int order;
        size_t alloc_size, size = vb->bsize; /* vb->bsize is page aligned */
        struct page *page;
        int max_pages, err = 0, i = 0;
        struct videobuf_dmabuf *dma = videobuf_to_dma(vb);

        /*
         * allocate maximum size scatter-gather list. Note this is
         * overhead. We may not use as many entries as we allocate
         */
        max_pages = vb->bsize >> PAGE_SHIFT;
        dma->sglist = kcalloc(max_pages, sizeof(*dma->sglist), GFP_KERNEL);
        if (dma->sglist == NULL) {
                err = -ENOMEM;
                goto out;
        }

        while (size) {
                order = get_order(size);
                /*
                 * do not over-allocate even if we would get larger
                 * contiguous chunk that way
                 */
                if ((PAGE_SIZE << order) > size)
                        order--;

                /* try to allocate as many contiguous pages as possible */
                page = alloc_pages(GFP_KERNEL, order);
                /* if allocation fails, try to allocate smaller amount */
                while (page == NULL) {
                        order--;
                        page = alloc_pages(GFP_KERNEL, order);
                        if (page == NULL && !order) {
                                err = -ENOMEM;
                                goto out;
                        }
                }
                size -= (PAGE_SIZE << order);

                /* append allocated chunk of pages into scatter-gather list */
                sg_set_page(&dma->sglist[i], page, PAGE_SIZE << order, 0);
                dma->sglen++;
                i++;

                alloc_size = (PAGE_SIZE << order);

                /* clear pages before giving them to user space */
                memset(page_address(page), 0, alloc_size);

                /* mark allocated pages reserved */
                do {
                        SetPageReserved(page++);
                } while (alloc_size -= PAGE_SIZE);
        }
        /*
         * REVISIT: not fully correct to assign nr_pages == sglen but
         * video-buf is passing nr_pages for e.g. unmap_sg calls
         */
        dma->nr_pages = dma->sglen;
        dma->direction = PCI_DMA_FROMDEVICE;

        return 0;

out:
        omap24xxcam_vbq_free_mmap_buffer(vb);
        return err;
}

static int omap24xxcam_vbq_alloc_mmap_buffers(struct videobuf_queue *vbq,
                                              unsigned int count)
{
        int i, err = 0;
        struct omap24xxcam_fh *fh =
                container_of(vbq, struct omap24xxcam_fh, vbq);

        mutex_lock(&vbq->vb_lock);

        for (i = 0; i < count; i++) {
                err = omap24xxcam_vbq_alloc_mmap_buffer(vbq->bufs[i]);
                if (err)
                        goto out;
                dev_dbg(fh->cam->dev, "sglen is %d for buffer %d\n",
                        videobuf_to_dma(vbq->bufs[i])->sglen, i);
        }

        mutex_unlock(&vbq->vb_lock);

        return 0;
out:
        while (i) {
                i--;
                omap24xxcam_vbq_free_mmap_buffer(vbq->bufs[i]);
        }

        mutex_unlock(&vbq->vb_lock);

        return err;
}

/*
 * This routine is called from interrupt context when a scatter-gather DMA
 * transfer of a videobuf_buffer completes.
 */
static void omap24xxcam_vbq_complete(struct omap24xxcam_sgdma *sgdma,
                                     u32 csr, void *arg)
{
        struct omap24xxcam_device *cam =
                container_of(sgdma, struct omap24xxcam_device, sgdma);
        struct omap24xxcam_fh *fh = cam->streaming->private_data;
        struct videobuf_buffer *vb = (struct videobuf_buffer *)arg;
        const u32 csr_error = CAMDMA_CSR_MISALIGNED_ERR
                | CAMDMA_CSR_SUPERVISOR_ERR | CAMDMA_CSR_SECURE_ERR
                | CAMDMA_CSR_TRANS_ERR | CAMDMA_CSR_DROP;
        unsigned long flags;

        spin_lock_irqsave(&cam->core_enable_disable_lock, flags);
        if (--cam->sgdma_in_queue == 0)
                omap24xxcam_core_disable(cam);
        spin_unlock_irqrestore(&cam->core_enable_disable_lock, flags);

        do_gettimeofday(&vb->ts);
        vb->field_count = atomic_add_return(2, &fh->field_count);
        if (csr & csr_error) {
                vb->state = VIDEOBUF_ERROR;
                if (!atomic_read(&fh->cam->in_reset)) {
                        dev_dbg(cam->dev, "resetting camera, csr 0x%x\n", csr);
                        omap24xxcam_reset(cam);
                }
        } else
                vb->state = VIDEOBUF_DONE;
        wake_up(&vb->done);
}

static void omap24xxcam_vbq_release(struct videobuf_queue *vbq,
                                    struct videobuf_buffer *vb)
{
        struct videobuf_dmabuf *dma = videobuf_to_dma(vb);

        /* wait for buffer, especially to get out of the sgdma queue */
        videobuf_waiton(vbq, vb, 0, 0);
        if (vb->memory == V4L2_MEMORY_MMAP) {
                dma_unmap_sg(vbq->dev, dma->sglist, dma->sglen,
                             dma->direction);
                dma->direction = DMA_NONE;
        } else {
                videobuf_dma_unmap(vbq->dev, videobuf_to_dma(vb));
                videobuf_dma_free(videobuf_to_dma(vb));
        }

        vb->state = VIDEOBUF_NEEDS_INIT;
}

/*
 * Limit the number of available kernel image capture buffers based on the
 * number requested, the currently selected image size, and the maximum
 * amount of memory permitted for kernel capture buffers.
 */
static int omap24xxcam_vbq_setup(struct videobuf_queue *vbq, unsigned int *cnt,
                                 unsigned int *size)
{
        struct omap24xxcam_fh *fh = vbq->priv_data;

        if (*cnt <= 0)
                *cnt = VIDEO_MAX_FRAME; /* supply a default number of buffers */

        if (*cnt > VIDEO_MAX_FRAME)
                *cnt = VIDEO_MAX_FRAME;

        *size = fh->pix.sizeimage;

        /* accessing fh->cam->capture_mem is ok, it's constant */
        if (*size * *cnt > fh->cam->capture_mem)
                *cnt = fh->cam->capture_mem / *size;

        return 0;
}

static int omap24xxcam_dma_iolock(struct videobuf_queue *vbq,
                                  struct videobuf_dmabuf *dma)
{
        int err = 0;

        dma->direction = PCI_DMA_FROMDEVICE;
        if (!dma_map_sg(vbq->dev, dma->sglist, dma->sglen, dma->direction)) {
                kfree(dma->sglist);
                dma->sglist = NULL;
                dma->sglen = 0;
                err = -EIO;
        }

        return err;
}

static int omap24xxcam_vbq_prepare(struct videobuf_queue *vbq,
                                   struct videobuf_buffer *vb,
                                   enum v4l2_field field)
{
        struct omap24xxcam_fh *fh = vbq->priv_data;
        int err = 0;

        /*
         * Accessing pix here is okay since it's constant while
         * streaming is on (and we only get called then).
         */
        if (vb->baddr) {
                /* This is a userspace buffer. */
                if (fh->pix.sizeimage > vb->bsize) {
                        /* The buffer isn't big enough. */
                        err = -EINVAL;
                } else
                        vb->size = fh->pix.sizeimage;
        } else {
                if (vb->state != VIDEOBUF_NEEDS_INIT) {
                        /*
                         * We have a kernel bounce buffer that has
                         * already been allocated.
                         */
                        if (fh->pix.sizeimage > vb->size) {
                                /*
                                 * The image size has been changed to
                                 * a larger size since this buffer was
                                 * allocated, so we need to free and
                                 * reallocate it.
                                 */
                                omap24xxcam_vbq_release(vbq, vb);
                                vb->size = fh->pix.sizeimage;
                        }
                } else {
                        /* We need to allocate a new kernel bounce buffer. */
                        vb->size = fh->pix.sizeimage;
                }
        }

        if (err)
                return err;

        vb->width = fh->pix.width;
        vb->height = fh->pix.height;
        vb->field = field;

        if (vb->state == VIDEOBUF_NEEDS_INIT) {
                if (vb->memory == V4L2_MEMORY_MMAP)
                        /*
                         * we have built the scatter-gather list by ourself so
                         * do the scatter-gather mapping as well
                         */
                        err = omap24xxcam_dma_iolock(vbq, videobuf_to_dma(vb));
                else
                        err = videobuf_iolock(vbq, vb, NULL);
        }

        if (!err)
                vb->state = VIDEOBUF_PREPARED;
        else
                omap24xxcam_vbq_release(vbq, vb);

        return err;
}

static void omap24xxcam_vbq_queue(struct videobuf_queue *vbq,
                                  struct videobuf_buffer *vb)
{
        struct omap24xxcam_fh *fh = vbq->priv_data;
        struct omap24xxcam_device *cam = fh->cam;
        enum videobuf_state state = vb->state;
        unsigned long flags;
        int err;

        /*
         * FIXME: We're marking the buffer active since we have no
         * pretty way of marking it active exactly when the
         * scatter-gather transfer starts.
         */
        vb->state = VIDEOBUF_ACTIVE;

        err = omap24xxcam_sgdma_queue(&fh->cam->sgdma,
                                      videobuf_to_dma(vb)->sglist,
                                      videobuf_to_dma(vb)->sglen, vb->size,
                                      omap24xxcam_vbq_complete, vb);

        if (!err) {
                spin_lock_irqsave(&cam->core_enable_disable_lock, flags);
                if (++cam->sgdma_in_queue == 1
                    && !atomic_read(&cam->in_reset))
                        omap24xxcam_core_enable(cam);
                spin_unlock_irqrestore(&cam->core_enable_disable_lock, flags);
        } else {
                /*
                 * Oops. We're not supposed to get any errors here.
                 * The only way we could get an error is if we ran out
                 * of scatter-gather DMA slots, but we are supposed to
                 * have at least as many scatter-gather DMA slots as
                 * video buffers so that can't happen.
                 */
                dev_err(cam->dev, "failed to queue a video buffer for dma!\n");
                dev_err(cam->dev, "likely a bug in the driver!\n");
                vb->state = state;
        }
}

static struct videobuf_queue_ops omap24xxcam_vbq_ops = {
        .buf_setup   = omap24xxcam_vbq_setup,
        .buf_prepare = omap24xxcam_vbq_prepare,
        .buf_queue   = omap24xxcam_vbq_queue,
        .buf_release = omap24xxcam_vbq_release,
};

/*
 *
 * OMAP main camera system
 *
 */

/*
 * Reset camera block to power-on state.
 */
static void omap24xxcam_poweron_reset(struct omap24xxcam_device *cam)
{
        int max_loop = RESET_TIMEOUT_NS;

        /* Reset whole camera subsystem */
        omap24xxcam_reg_out(cam->mmio_base,
                            CAM_SYSCONFIG,
                            CAM_SYSCONFIG_SOFTRESET);

        /* Wait till it's finished */
        while (!(omap24xxcam_reg_in(cam->mmio_base, CAM_SYSSTATUS)
                 & CAM_SYSSTATUS_RESETDONE)
               && --max_loop) {
                ndelay(1);
        }

        if (!(omap24xxcam_reg_in(cam->mmio_base, CAM_SYSSTATUS)
              & CAM_SYSSTATUS_RESETDONE))
                dev_err(cam->dev, "camera soft reset timeout\n");
}

/*
 * (Re)initialise the camera block.
 */
static void omap24xxcam_hwinit(struct omap24xxcam_device *cam)
{
        omap24xxcam_poweron_reset(cam);

        /* set the camera subsystem autoidle bit */
        omap24xxcam_reg_out(cam->mmio_base, CAM_SYSCONFIG,
                            CAM_SYSCONFIG_AUTOIDLE);

        /* set the camera MMU autoidle bit */
        omap24xxcam_reg_out(cam->mmio_base,
                            CAMMMU_REG_OFFSET + CAMMMU_SYSCONFIG,
                            CAMMMU_SYSCONFIG_AUTOIDLE);

        omap24xxcam_core_hwinit(cam);

        omap24xxcam_dma_hwinit(&cam->sgdma.dma);
}

/*
 * Callback for dma transfer stalling.
 */
static void omap24xxcam_stalled_dma_reset(unsigned long data)
{
        struct omap24xxcam_device *cam = (struct omap24xxcam_device *)data;

        if (!atomic_read(&cam->in_reset)) {
                dev_dbg(cam->dev, "dma stalled, resetting camera\n");
                omap24xxcam_reset(cam);
        }
}

/*
 * Stop capture. Mark we're doing a reset, stop DMA transfers and
 * core. (No new scatter-gather transfers will be queued whilst
 * in_reset is non-zero.)
 *
 * If omap24xxcam_capture_stop is called from several places at
 * once, only the first call will have an effect. Similarly, the last
 * call omap24xxcam_streaming_cont will have effect.
 *
 * Serialisation is ensured by using cam->core_enable_disable_lock.
 */
static void omap24xxcam_capture_stop(struct omap24xxcam_device *cam)
{
        unsigned long flags;

        spin_lock_irqsave(&cam->core_enable_disable_lock, flags);

        if (atomic_inc_return(&cam->in_reset) != 1) {
                spin_unlock_irqrestore(&cam->core_enable_disable_lock, flags);
                return;
        }

        omap24xxcam_core_disable(cam);

        spin_unlock_irqrestore(&cam->core_enable_disable_lock, flags);

        omap24xxcam_sgdma_sync(&cam->sgdma);
}

/*
 * Reset and continue streaming.
 *
 * Note: Resetting the camera FIFO via the CC_RST bit in the CC_CTRL
 * register is supposed to be sufficient to recover from a camera
 * interface error, but it doesn't seem to be enough. If we only do
 * that then subsequent image captures are out of sync by either one
 * or two times DMA_THRESHOLD bytes. Resetting and re-initializing the
 * entire camera subsystem prevents the problem with frame
 * synchronization.
 */
static void omap24xxcam_capture_cont(struct omap24xxcam_device *cam)
{
        unsigned long flags;

        spin_lock_irqsave(&cam->core_enable_disable_lock, flags);

        if (atomic_read(&cam->in_reset) != 1)
                goto out;

        omap24xxcam_hwinit(cam);

        omap24xxcam_sensor_if_enable(cam);

        omap24xxcam_sgdma_process(&cam->sgdma);

        if (cam->sgdma_in_queue)
                omap24xxcam_core_enable(cam);

out:
        atomic_dec(&cam->in_reset);
        spin_unlock_irqrestore(&cam->core_enable_disable_lock, flags);
}

static ssize_t
omap24xxcam_streaming_show(struct device *dev, struct device_attribute *attr,
                char *buf)
{
        struct omap24xxcam_device *cam = dev_get_drvdata(dev);

        return sprintf(buf, "%s\n", cam->streaming ?  "active" : "inactive");
}
static DEVICE_ATTR(streaming, S_IRUGO, omap24xxcam_streaming_show, NULL);

/*
 * Stop capture and restart it. I.e. reset the camera during use.
 */
static void omap24xxcam_reset(struct omap24xxcam_device *cam)
{
        omap24xxcam_capture_stop(cam);
        omap24xxcam_capture_cont(cam);
}

/*
 * The main interrupt handler.
 */
static irqreturn_t omap24xxcam_isr(int irq, void *arg)
{
        struct omap24xxcam_device *cam = (struct omap24xxcam_device *)arg;
        u32 irqstatus;
        unsigned int irqhandled = 0;

        irqstatus = omap24xxcam_reg_in(cam->mmio_base, CAM_IRQSTATUS);

        if (irqstatus &
            (CAM_IRQSTATUS_DMA_IRQ2 | CAM_IRQSTATUS_DMA_IRQ1
             | CAM_IRQSTATUS_DMA_IRQ0)) {
                omap24xxcam_dma_isr(&cam->sgdma.dma);
                irqhandled = 1;
        }
        if (irqstatus & CAM_IRQSTATUS_CC_IRQ) {
                omap24xxcam_core_isr(cam);
                irqhandled = 1;
        }
        if (irqstatus & CAM_IRQSTATUS_MMU_IRQ)
                dev_err(cam->dev, "unhandled camera MMU interrupt!\n");

        return IRQ_RETVAL(irqhandled);
}

/*
 *
 * Sensor handling.
 *
 */

/*
 * Enable the external sensor interface. Try to negotiate interface
 * parameters with the sensor and start using the new ones. The calls
 * to sensor_if_enable and sensor_if_disable need not to be balanced.
 */
static int omap24xxcam_sensor_if_enable(struct omap24xxcam_device *cam)
{
        int rval;
        struct v4l2_ifparm p;

        rval = vidioc_int_g_ifparm(cam->sdev, &p);
        if (rval) {
                dev_err(cam->dev, "vidioc_int_g_ifparm failed with %d\n", rval);
                return rval;
        }

        cam->if_type = p.if_type;

        cam->cc_ctrl = CC_CTRL_CC_EN;

        switch (p.if_type) {
        case V4L2_IF_TYPE_BT656:
                if (p.u.bt656.frame_start_on_rising_vs)
                        cam->cc_ctrl |= CC_CTRL_NOBT_SYNCHRO;
                if (p.u.bt656.bt_sync_correct)
                        cam->cc_ctrl |= CC_CTRL_BT_CORRECT;
                if (p.u.bt656.swap)
                        cam->cc_ctrl |= CC_CTRL_PAR_ORDERCAM;
                if (p.u.bt656.latch_clk_inv)
                        cam->cc_ctrl |= CC_CTRL_PAR_CLK_POL;
                if (p.u.bt656.nobt_hs_inv)
                        cam->cc_ctrl |= CC_CTRL_NOBT_HS_POL;
                if (p.u.bt656.nobt_vs_inv)
                        cam->cc_ctrl |= CC_CTRL_NOBT_VS_POL;

                switch (p.u.bt656.mode) {
                case V4L2_IF_TYPE_BT656_MODE_NOBT_8BIT:
                        cam->cc_ctrl |= CC_CTRL_PAR_MODE_NOBT8;
                        break;
                case V4L2_IF_TYPE_BT656_MODE_NOBT_10BIT:
                        cam->cc_ctrl |= CC_CTRL_PAR_MODE_NOBT10;
                        break;
                case V4L2_IF_TYPE_BT656_MODE_NOBT_12BIT:
                        cam->cc_ctrl |= CC_CTRL_PAR_MODE_NOBT12;
                        break;
                case V4L2_IF_TYPE_BT656_MODE_BT_8BIT:
                        cam->cc_ctrl |= CC_CTRL_PAR_MODE_BT8;
                        break;
                case V4L2_IF_TYPE_BT656_MODE_BT_10BIT:
                        cam->cc_ctrl |= CC_CTRL_PAR_MODE_BT10;
                        break;
                default:
                        dev_err(cam->dev,
                                "bt656 interface mode %d not supported\n",
                                p.u.bt656.mode);
                        return -EINVAL;
                }
                /*
                 * The clock rate that the sensor wants has changed.
                 * We have to adjust the xclk from OMAP 2 side to
                 * match the sensor's wish as closely as possible.
                 */
                if (p.u.bt656.clock_curr != cam->if_u.bt656.xclk) {
                        u32 xclk = p.u.bt656.clock_curr;
                        u32 divisor;

                        if (xclk == 0)
                                return -EINVAL;

                        if (xclk > CAM_MCLK)
                                xclk = CAM_MCLK;

                        divisor = CAM_MCLK / xclk;
                        if (divisor * xclk < CAM_MCLK)
                                divisor++;
                        if (CAM_MCLK / divisor < p.u.bt656.clock_min
                            && divisor > 1)
                                divisor--;
                        if (divisor > 30)
                                divisor = 30;

                        xclk = CAM_MCLK / divisor;

                        if (xclk < p.u.bt656.clock_min
                            || xclk > p.u.bt656.clock_max)
                                return -EINVAL;

                        cam->if_u.bt656.xclk = xclk;
                }
                omap24xxcam_core_xclk_set(cam, cam->if_u.bt656.xclk);
                break;
        default:
                /* FIXME: how about other interfaces? */
                dev_err(cam->dev, "interface type %d not supported\n",
                        p.if_type);
                return -EINVAL;
        }

        return 0;
}

static void omap24xxcam_sensor_if_disable(const struct omap24xxcam_device *cam)
{
        switch (cam->if_type) {
        case V4L2_IF_TYPE_BT656:
                omap24xxcam_core_xclk_set(cam, 0);
                break;
        }
}

/*
 * Initialise the sensor hardware.
 */
static int omap24xxcam_sensor_init(struct omap24xxcam_device *cam)
{
        int err = 0;
        struct v4l2_int_device *sdev = cam->sdev;

        omap24xxcam_clock_on(cam);
        err = omap24xxcam_sensor_if_enable(cam);
        if (err) {
                dev_err(cam->dev, "sensor interface could not be enabled at "
                        "initialisation, %d\n", err);
                cam->sdev = NULL;
                goto out;
        }

        /* power up sensor during sensor initialization */
        vidioc_int_s_power(sdev, 1);

        err = vidioc_int_dev_init(sdev);
        if (err) {
                dev_err(cam->dev, "cannot initialize sensor, error %d\n", err);
                /* Sensor init failed --- it's nonexistent to us! */
                cam->sdev = NULL;
                goto out;
        }

        dev_info(cam->dev, "sensor is %s\n", sdev->name);

out:
        omap24xxcam_sensor_if_disable(cam);
        omap24xxcam_clock_off(cam);

        vidioc_int_s_power(sdev, 0);

        return err;
}

static void omap24xxcam_sensor_exit(struct omap24xxcam_device *cam)
{
        if (cam->sdev)
                vidioc_int_dev_exit(cam->sdev);
}

static void omap24xxcam_sensor_disable(struct omap24xxcam_device *cam)
{
        omap24xxcam_sensor_if_disable(cam);
        omap24xxcam_clock_off(cam);
        vidioc_int_s_power(cam->sdev, 0);
}

/*
 * Power-up and configure camera sensor. It's ready for capturing now.
 */
static int omap24xxcam_sensor_enable(struct omap24xxcam_device *cam)
{
        int rval;

        omap24xxcam_clock_on(cam);

        omap24xxcam_sensor_if_enable(cam);

        rval = vidioc_int_s_power(cam->sdev, 1);
        if (rval)
                goto out;

        rval = vidioc_int_init(cam->sdev);
        if (rval)
                goto out;

        return 0;

out:
        omap24xxcam_sensor_disable(cam);

        return rval;
}

static void omap24xxcam_sensor_reset_work(struct work_struct *work)
{
        struct omap24xxcam_device *cam =
                container_of(work, struct omap24xxcam_device,
                             sensor_reset_work);

        if (atomic_read(&cam->reset_disable))
                return;

        omap24xxcam_capture_stop(cam);

        if (vidioc_int_reset(cam->sdev) == 0) {
                vidioc_int_init(cam->sdev);
        } else {
                /* Can't reset it by vidioc_int_reset. */
                omap24xxcam_sensor_disable(cam);
                omap24xxcam_sensor_enable(cam);
        }

        omap24xxcam_capture_cont(cam);
}

/*
 *
 * IOCTL interface.
 *
 */

static int vidioc_querycap(struct file *file, void *fh,
                           struct v4l2_capability *cap)
{
        struct omap24xxcam_fh *ofh = fh;
        struct omap24xxcam_device *cam = ofh->cam;

        strlcpy(cap->driver, CAM_NAME, sizeof(cap->driver));
        strlcpy(cap->card, cam->vfd->name, sizeof(cap->card));
        cap->capabilities = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_STREAMING;

        return 0;
}

static int vidioc_enum_fmt_vid_cap(struct file *file, void *fh,
                                   struct v4l2_fmtdesc *f)
{
        struct omap24xxcam_fh *ofh = fh;
        struct omap24xxcam_device *cam = ofh->cam;
        int rval;

        rval = vidioc_int_enum_fmt_cap(cam->sdev, f);

        return rval;
}

static int vidioc_g_fmt_vid_cap(struct file *file, void *fh,
                                struct v4l2_format *f)
{
        struct omap24xxcam_fh *ofh = fh;
        struct omap24xxcam_device *cam = ofh->cam;
        int rval;

        mutex_lock(&cam->mutex);
        rval = vidioc_int_g_fmt_cap(cam->sdev, f);
        mutex_unlock(&cam->mutex);

        return rval;
}

static int vidioc_s_fmt_vid_cap(struct file *file, void *fh,
                                struct v4l2_format *f)
{
        struct omap24xxcam_fh *ofh = fh;
        struct omap24xxcam_device *cam = ofh->cam;
        int rval;

        mutex_lock(&cam->mutex);
        if (cam->streaming) {
                rval = -EBUSY;
                goto out;
        }

        rval = vidioc_int_s_fmt_cap(cam->sdev, f);

out:
        mutex_unlock(&cam->mutex);

        if (!rval) {
                mutex_lock(&ofh->vbq.vb_lock);
                ofh->pix = f->fmt.pix;
                mutex_unlock(&ofh->vbq.vb_lock);
        }

        memset(f, 0, sizeof(*f));
        vidioc_g_fmt_vid_cap(file, fh, f);

        return rval;
}

static int vidioc_try_fmt_vid_cap(struct file *file, void *fh,
                                  struct v4l2_format *f)
{
        struct omap24xxcam_fh *ofh = fh;
        struct omap24xxcam_device *cam = ofh->cam;
        int rval;

        mutex_lock(&cam->mutex);
        rval = vidioc_int_try_fmt_cap(cam->sdev, f);
        mutex_unlock(&cam->mutex);

        return rval;
}

static int vidioc_reqbufs(struct file *file, void *fh,
                          struct v4l2_requestbuffers *b)
{
        struct omap24xxcam_fh *ofh = fh;
        struct omap24xxcam_device *cam = ofh->cam;
        int rval;

        mutex_lock(&cam->mutex);
        if (cam->streaming) {
                mutex_unlock(&cam->mutex);
                return -EBUSY;
        }

        omap24xxcam_vbq_free_mmap_buffers(&ofh->vbq);
        mutex_unlock(&cam->mutex);

        rval = videobuf_reqbufs(&ofh->vbq, b);

        /*
         * Either videobuf_reqbufs failed or the buffers are not
         * memory-mapped (which would need special attention).
         */
        if (rval < 0 || b->memory != V4L2_MEMORY_MMAP)
                goto out;

        rval = omap24xxcam_vbq_alloc_mmap_buffers(&ofh->vbq, rval);
        if (rval)
                omap24xxcam_vbq_free_mmap_buffers(&ofh->vbq);

out:
        return rval;
}

static int vidioc_querybuf(struct file *file, void *fh,
                           struct v4l2_buffer *b)
{
        struct omap24xxcam_fh *ofh = fh;

        return videobuf_querybuf(&ofh->vbq, b);
}

static int vidioc_qbuf(struct file *file, void *fh, struct v4l2_buffer *b)
{
        struct omap24xxcam_fh *ofh = fh;

        return videobuf_qbuf(&ofh->vbq, b);
}

static int vidioc_dqbuf(struct file *file, void *fh, struct v4l2_buffer *b)
{
        struct omap24xxcam_fh *ofh = fh;
        struct omap24xxcam_device *cam = ofh->cam;
        struct videobuf_buffer *vb;
        int rval;

videobuf_dqbuf_again:
        rval = videobuf_dqbuf(&ofh->vbq, b, file->f_flags & O_NONBLOCK);
        if (rval)
                goto out;

        vb = ofh->vbq.bufs[b->index];

        mutex_lock(&cam->mutex);
        /* _needs_reset returns -EIO if reset is required. */
        rval = vidioc_int_g_needs_reset(cam->sdev, (void *)vb->baddr);
        mutex_unlock(&cam->mutex);
        if (rval == -EIO)
                schedule_work(&cam->sensor_reset_work);
        else
                rval = 0;

out:
        /*
         * This is a hack. We don't want to show -EIO to the user
         * space. Requeue the buffer and try again if we're not doing
         * this in non-blocking mode.
         */
        if (rval == -EIO) {
                videobuf_qbuf(&ofh->vbq, b);
                if (!(file->f_flags & O_NONBLOCK))
                        goto videobuf_dqbuf_again;
                /*
                 * We don't have a videobuf_buffer now --- maybe next
                 * time...
                 */
                rval = -EAGAIN;
        }

        return rval;
}

static int vidioc_streamon(struct file *file, void *fh, enum v4l2_buf_type i)
{
        struct omap24xxcam_fh *ofh = fh;
        struct omap24xxcam_device *cam = ofh->cam;
        int rval;

        mutex_lock(&cam->mutex);
        if (cam->streaming) {
                rval = -EBUSY;
                goto out;
        }

        rval = omap24xxcam_sensor_if_enable(cam);
        if (rval) {
                dev_dbg(cam->dev, "vidioc_int_g_ifparm failed\n");
                goto out;
        }

        rval = videobuf_streamon(&ofh->vbq);
        if (!rval) {
                cam->streaming = file;
                sysfs_notify(&cam->dev->kobj, NULL, "streaming");
        }

out:
        mutex_unlock(&cam->mutex);

        return rval;
}

static int vidioc_streamoff(struct file *file, void *fh, enum v4l2_buf_type i)
{
        struct omap24xxcam_fh *ofh = fh;
        struct omap24xxcam_device *cam = ofh->cam;
        struct videobuf_queue *q = &ofh->vbq;
        int rval;

        atomic_inc(&cam->reset_disable);

        flush_work_sync(&cam->sensor_reset_work);

        rval = videobuf_streamoff(q);
        if (!rval) {
                mutex_lock(&cam->mutex);
                cam->streaming = NULL;
                mutex_unlock(&cam->mutex);
                sysfs_notify(&cam->dev->kobj, NULL, "streaming");
        }

        atomic_dec(&cam->reset_disable);

        return rval;
}

static int vidioc_enum_input(struct file *file, void *fh,
                             struct v4l2_input *inp)
{
        if (inp->index > 0)
                return -EINVAL;

        strlcpy(inp->name, "camera", sizeof(inp->name));
        inp->type = V4L2_INPUT_TYPE_CAMERA;

        return 0;
}

static int vidioc_g_input(struct file *file, void *fh, unsigned int *i)
{
        *i = 0;

        return 0;
}

static int vidioc_s_input(struct file *file, void *fh, unsigned int i)
{
        if (i > 0)
                return -EINVAL;

        return 0;
}

static int vidioc_queryctrl(struct file *file, void *fh,
                            struct v4l2_queryctrl *a)
{
        struct omap24xxcam_fh *ofh = fh;
        struct omap24xxcam_device *cam = ofh->cam;
        int rval;

        rval = vidioc_int_queryctrl(cam->sdev, a);

        return rval;
}

static int vidioc_g_ctrl(struct file *file, void *fh,
                         struct v4l2_control *a)
{
        struct omap24xxcam_fh *ofh = fh;
        struct omap24xxcam_device *cam = ofh->cam;
        int rval;

        mutex_lock(&cam->mutex);
        rval = vidioc_int_g_ctrl(cam->sdev, a);
        mutex_unlock(&cam->mutex);

        return rval;
}

static int vidioc_s_ctrl(struct file *file, void *fh,
                         struct v4l2_control *a)
{
        struct omap24xxcam_fh *ofh = fh;
        struct omap24xxcam_device *cam = ofh->cam;
        int rval;

        mutex_lock(&cam->mutex);
        rval = vidioc_int_s_ctrl(cam->sdev, a);
        mutex_unlock(&cam->mutex);

        return rval;
}

static int vidioc_g_parm(struct file *file, void *fh,
                         struct v4l2_streamparm *a) {
        struct omap24xxcam_fh *ofh = fh;
        struct omap24xxcam_device *cam = ofh->cam;
        int rval;

        mutex_lock(&cam->mutex);
        rval = vidioc_int_g_parm(cam->sdev, a);
        mutex_unlock(&cam->mutex);

        return rval;
}

static int vidioc_s_parm(struct file *file, void *fh,
                         struct v4l2_streamparm *a)
{
        struct omap24xxcam_fh *ofh = fh;
        struct omap24xxcam_device *cam = ofh->cam;
        struct v4l2_streamparm old_streamparm;
        int rval;

        mutex_lock(&cam->mutex);
        if (cam->streaming) {
                rval = -EBUSY;
                goto out;
        }

        old_streamparm.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
        rval = vidioc_int_g_parm(cam->sdev, &old_streamparm);
        if (rval)
                goto out;

        rval = vidioc_int_s_parm(cam->sdev, a);
        if (rval)
                goto out;

        rval = omap24xxcam_sensor_if_enable(cam);
        /*
         * Revert to old streaming parameters if enabling sensor
         * interface with the new ones failed.
         */
        if (rval)
                vidioc_int_s_parm(cam->sdev, &old_streamparm);

out:
        mutex_unlock(&cam->mutex);

        return rval;
}

/*
 *
 * File operations.
 *
 */

static unsigned int omap24xxcam_poll(struct file *file,
                                     struct poll_table_struct *wait)
{
        struct omap24xxcam_fh *fh = file->private_data;
        struct omap24xxcam_device *cam = fh->cam;
        struct videobuf_buffer *vb;

        mutex_lock(&cam->mutex);
        if (cam->streaming != file) {
                mutex_unlock(&cam->mutex);
                return POLLERR;
        }
        mutex_unlock(&cam->mutex);

        mutex_lock(&fh->vbq.vb_lock);
        if (list_empty(&fh->vbq.stream)) {
                mutex_unlock(&fh->vbq.vb_lock);
                return POLLERR;
        }
        vb = list_entry(fh->vbq.stream.next, struct videobuf_buffer, stream);
        mutex_unlock(&fh->vbq.vb_lock);

        poll_wait(file, &vb->done, wait);

        if (vb->state == VIDEOBUF_DONE || vb->state == VIDEOBUF_ERROR)
                return POLLIN | POLLRDNORM;

        return 0;
}

static int omap24xxcam_mmap_buffers(struct file *file,
                                    struct vm_area_struct *vma)
{
        struct omap24xxcam_fh *fh = file->private_data;
        struct omap24xxcam_device *cam = fh->cam;
        struct videobuf_queue *vbq = &fh->vbq;
        unsigned int first, last, size, i, j;
        int err = 0;

        mutex_lock(&cam->mutex);
        if (cam->streaming) {
                mutex_unlock(&cam->mutex);
                return -EBUSY;
        }
        mutex_unlock(&cam->mutex);
        mutex_lock(&vbq->vb_lock);

        /* look for first buffer to map */
        for (first = 0; first < VIDEO_MAX_FRAME; first++) {
                if (NULL == vbq->bufs[first])
                        continue;
                if (V4L2_MEMORY_MMAP != vbq->bufs[first]->memory)
                        continue;
                if (vbq->bufs[first]->boff == (vma->vm_pgoff << PAGE_SHIFT))
                        break;
        }

        /* look for last buffer to map */
        for (size = 0, last = first; last < VIDEO_MAX_FRAME; last++) {
                if (NULL == vbq->bufs[last])
                        continue;
                if (V4L2_MEMORY_MMAP != vbq->bufs[last]->memory)
                        continue;
                size += vbq->bufs[last]->bsize;
                if (size == (vma->vm_end - vma->vm_start))
                        break;
        }

        size = 0;
        for (i = first; i <= last && i < VIDEO_MAX_FRAME; i++) {
                struct videobuf_dmabuf *dma = videobuf_to_dma(vbq->bufs[i]);

                for (j = 0; j < dma->sglen; j++) {
                        err = remap_pfn_range(
                                vma, vma->vm_start + size,
                                page_to_pfn(sg_page(&dma->sglist[j])),
                                sg_dma_len(&dma->sglist[j]), vma->vm_page_prot);
                        if (err)
                                goto out;
                        size += sg_dma_len(&dma->sglist[j]);
                }
        }

out:
        mutex_unlock(&vbq->vb_lock);

        return err;
}

static int omap24xxcam_mmap(struct file *file, struct vm_area_struct *vma)
{
        struct omap24xxcam_fh *fh = file->private_data;
        int rval;

        /* let the video-buf mapper check arguments and set-up structures */
        rval = videobuf_mmap_mapper(&fh->vbq, vma);
        if (rval)
                return rval;

        vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

        /* do mapping to our allocated buffers */
        rval = omap24xxcam_mmap_buffers(file, vma);
        /*
         * In case of error, free vma->vm_private_data allocated by
         * videobuf_mmap_mapper.
         */
        if (rval)
                kfree(vma->vm_private_data);

        return rval;
}

static int omap24xxcam_open(struct file *file)
{
        struct omap24xxcam_device *cam = omap24xxcam.priv;
        struct omap24xxcam_fh *fh;
        struct v4l2_format format;

        if (!cam || !cam->vfd)
                return -ENODEV;

        fh = kzalloc(sizeof(*fh), GFP_KERNEL);
        if (fh == NULL)
                return -ENOMEM;

        mutex_lock(&cam->mutex);
        if (cam->sdev == NULL || !try_module_get(cam->sdev->module)) {
                mutex_unlock(&cam->mutex);
                goto out_try_module_get;
        }

        if (atomic_inc_return(&cam->users) == 1) {
                omap24xxcam_hwinit(cam);
                if (omap24xxcam_sensor_enable(cam)) {
                        mutex_unlock(&cam->mutex);
                        goto out_omap24xxcam_sensor_enable;
                }
        }
        mutex_unlock(&cam->mutex);

        fh->cam = cam;
        mutex_lock(&cam->mutex);
        vidioc_int_g_fmt_cap(cam->sdev, &format);
        mutex_unlock(&cam->mutex);
        /* FIXME: how about fh->pix when there are more users? */
        fh->pix = format.fmt.pix;

        file->private_data = fh;

        spin_lock_init(&fh->vbq_lock);

        videobuf_queue_sg_init(&fh->vbq, &omap24xxcam_vbq_ops, NULL,
                                &fh->vbq_lock, V4L2_BUF_TYPE_VIDEO_CAPTURE,
                                V4L2_FIELD_NONE,
                                sizeof(struct videobuf_buffer), fh, NULL);

        return 0;

out_omap24xxcam_sensor_enable:
        omap24xxcam_poweron_reset(cam);
        module_put(cam->sdev->module);

out_try_module_get:
        kfree(fh);

        return -ENODEV;
}

static int omap24xxcam_release(struct file *file)
{
        struct omap24xxcam_fh *fh = file->private_data;
        struct omap24xxcam_device *cam = fh->cam;

        atomic_inc(&cam->reset_disable);

        flush_work_sync(&cam->sensor_reset_work);

        /* stop streaming capture */
        videobuf_streamoff(&fh->vbq);

        mutex_lock(&cam->mutex);
        if (cam->streaming == file) {
                cam->streaming = NULL;
                mutex_unlock(&cam->mutex);
                sysfs_notify(&cam->dev->kobj, NULL, "streaming");
        } else {
                mutex_unlock(&cam->mutex);
        }

        atomic_dec(&cam->reset_disable);

        omap24xxcam_vbq_free_mmap_buffers(&fh->vbq);

        /*
         * Make sure the reset work we might have scheduled is not
         * pending! It may be run *only* if we have users. (And it may
         * not be scheduled anymore since streaming is already
         * disabled.)
         */
        flush_work_sync(&cam->sensor_reset_work);

        mutex_lock(&cam->mutex);
        if (atomic_dec_return(&cam->users) == 0) {
                omap24xxcam_sensor_disable(cam);
                omap24xxcam_poweron_reset(cam);
        }
        mutex_unlock(&cam->mutex);

        file->private_data = NULL;

        module_put(cam->sdev->module);
        kfree(fh);

        return 0;
}

static struct v4l2_file_operations omap24xxcam_fops = {
        .ioctl   = video_ioctl2,
        .poll    = omap24xxcam_poll,
        .mmap    = omap24xxcam_mmap,
        .open    = omap24xxcam_open,
        .release = omap24xxcam_release,
};

/*
 *
 * Power management.
 *
 */

#ifdef CONFIG_PM
static int omap24xxcam_suspend(struct platform_device *pdev, pm_message_t state)
{
        struct omap24xxcam_device *cam = platform_get_drvdata(pdev);

        if (atomic_read(&cam->users) == 0)
                return 0;

        if (!atomic_read(&cam->reset_disable))
                omap24xxcam_capture_stop(cam);

        omap24xxcam_sensor_disable(cam);
        omap24xxcam_poweron_reset(cam);

        return 0;
}

static int omap24xxcam_resume(struct platform_device *pdev)
{
        struct omap24xxcam_device *cam = platform_get_drvdata(pdev);

        if (atomic_read(&cam->users) == 0)
                return 0;

        omap24xxcam_hwinit(cam);
        omap24xxcam_sensor_enable(cam);

        if (!atomic_read(&cam->reset_disable))
                omap24xxcam_capture_cont(cam);

        return 0;
}
#endif /* CONFIG_PM */

static const struct v4l2_ioctl_ops omap24xxcam_ioctl_fops = {
        .vidioc_querycap        = vidioc_querycap,
        .vidioc_enum_fmt_vid_cap        = vidioc_enum_fmt_vid_cap,
        .vidioc_g_fmt_vid_cap   = vidioc_g_fmt_vid_cap,
        .vidioc_s_fmt_vid_cap   = vidioc_s_fmt_vid_cap,
        .vidioc_try_fmt_vid_cap = vidioc_try_fmt_vid_cap,
        .vidioc_reqbufs         = vidioc_reqbufs,
        .vidioc_querybuf        = vidioc_querybuf,
        .vidioc_qbuf            = vidioc_qbuf,
        .vidioc_dqbuf           = vidioc_dqbuf,
        .vidioc_streamon        = vidioc_streamon,
        .vidioc_streamoff       = vidioc_streamoff,
        .vidioc_enum_input      = vidioc_enum_input,
        .vidioc_g_input         = vidioc_g_input,
        .vidioc_s_input         = vidioc_s_input,
        .vidioc_queryctrl       = vidioc_queryctrl,
        .vidioc_g_ctrl          = vidioc_g_ctrl,
        .vidioc_s_ctrl          = vidioc_s_ctrl,
        .vidioc_g_parm          = vidioc_g_parm,
        .vidioc_s_parm          = vidioc_s_parm,
};

/*
 *
 * Camera device (i.e. /dev/video).
 *
 */

static int omap24xxcam_device_register(struct v4l2_int_device *s)
{
        struct omap24xxcam_device *cam = s->u.slave->master->priv;
        struct video_device *vfd;
        int rval;

        /* We already have a slave. */
        if (cam->sdev)
                return -EBUSY;

        cam->sdev = s;

        if (device_create_file(cam->dev, &dev_attr_streaming) != 0) {
                dev_err(cam->dev, "could not register sysfs entry\n");
                rval = -EBUSY;
                goto err;
        }

        /* initialize the video_device struct */
        vfd = cam->vfd = video_device_alloc();
        if (!vfd) {
                dev_err(cam->dev, "could not allocate video device struct\n");
                rval = -ENOMEM;
                goto err;
        }
        vfd->release = video_device_release;

        vfd->parent = cam->dev;

        strlcpy(vfd->name, CAM_NAME, sizeof(vfd->name));
        vfd->fops                = &omap24xxcam_fops;
        vfd->ioctl_ops           = &omap24xxcam_ioctl_fops;

        omap24xxcam_hwinit(cam);

        rval = omap24xxcam_sensor_init(cam);
        if (rval)
                goto err;

        if (video_register_device(vfd, VFL_TYPE_GRABBER, video_nr) < 0) {
                dev_err(cam->dev, "could not register V4L device\n");
                rval = -EBUSY;
                goto err;
        }

        omap24xxcam_poweron_reset(cam);

        dev_info(cam->dev, "registered device %s\n",
                 video_device_node_name(vfd));

        return 0;

err:
        omap24xxcam_device_unregister(s);

        return rval;
}

static void omap24xxcam_device_unregister(struct v4l2_int_device *s)
{
        struct omap24xxcam_device *cam = s->u.slave->master->priv;

        omap24xxcam_sensor_exit(cam);

        if (cam->vfd) {
                if (!video_is_registered(cam->vfd)) {
                        /*
                         * The device was never registered, so release the
                         * video_device struct directly.
                         */
                        video_device_release(cam->vfd);
                } else {
                        /*
                         * The unregister function will release the
                         * video_device struct as well as
                         * unregistering it.
                         */
                        video_unregister_device(cam->vfd);
                }
                cam->vfd = NULL;
        }

        device_remove_file(cam->dev, &dev_attr_streaming);

        cam->sdev = NULL;
}

static struct v4l2_int_master omap24xxcam_master = {
        .attach = omap24xxcam_device_register,
        .detach = omap24xxcam_device_unregister,
};

static struct v4l2_int_device omap24xxcam = {
        .module = THIS_MODULE,
        .name   = CAM_NAME,
        .type   = v4l2_int_type_master,
        .u      = {
                .master = &omap24xxcam_master
        },
};

/*
 *
 * Driver initialisation and deinitialisation.
 *
 */

static int __devinit omap24xxcam_probe(struct platform_device *pdev)
{
        struct omap24xxcam_device *cam;
        struct resource *mem;
        int irq;

        cam = kzalloc(sizeof(*cam), GFP_KERNEL);
        if (!cam) {
                dev_err(&pdev->dev, "could not allocate memory\n");
                goto err;
        }

        platform_set_drvdata(pdev, cam);

        cam->dev = &pdev->dev;

        /*
         * Impose a lower limit on the amount of memory allocated for
         * capture. We require at least enough memory to double-buffer
         * QVGA (300KB).
         */
        if (capture_mem < 320 * 240 * 2 * 2)
                capture_mem = 320 * 240 * 2 * 2;
        cam->capture_mem = capture_mem;

        /* request the mem region for the camera registers */
        mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!mem) {
                dev_err(cam->dev, "no mem resource?\n");
                goto err;
        }
        if (!request_mem_region(mem->start, resource_size(mem), pdev->name)) {
                dev_err(cam->dev,
                        "cannot reserve camera register I/O region\n");
                goto err;
        }
        cam->mmio_base_phys = mem->start;
        cam->mmio_size = resource_size(mem);

        /* map the region */
        cam->mmio_base = (unsigned long)
                ioremap_nocache(cam->mmio_base_phys, cam->mmio_size);
        if (!cam->mmio_base) {
                dev_err(cam->dev, "cannot map camera register I/O region\n");
                goto err;
        }

        irq = platform_get_irq(pdev, 0);
        if (irq <= 0) {
                dev_err(cam->dev, "no irq for camera?\n");
                goto err;
        }

        /* install the interrupt service routine */
        if (request_irq(irq, omap24xxcam_isr, 0, CAM_NAME, cam)) {
                dev_err(cam->dev,
                        "could not install interrupt service routine\n");
                goto err;
        }
        cam->irq = irq;

        if (omap24xxcam_clock_get(cam))
                goto err;

        INIT_WORK(&cam->sensor_reset_work, omap24xxcam_sensor_reset_work);

        mutex_init(&cam->mutex);
        spin_lock_init(&cam->core_enable_disable_lock);

        omap24xxcam_sgdma_init(&cam->sgdma,
                               cam->mmio_base + CAMDMA_REG_OFFSET,
                               omap24xxcam_stalled_dma_reset,
                               (unsigned long)cam);

        omap24xxcam.priv = cam;

        if (v4l2_int_device_register(&omap24xxcam))
                goto err;

        return 0;

err:
        omap24xxcam_remove(pdev);
        return -ENODEV;
}

static int omap24xxcam_remove(struct platform_device *pdev)
{
        struct omap24xxcam_device *cam = platform_get_drvdata(pdev);

        if (!cam)
                return 0;

        if (omap24xxcam.priv != NULL)
                v4l2_int_device_unregister(&omap24xxcam);
        omap24xxcam.priv = NULL;

        omap24xxcam_clock_put(cam);

        if (cam->irq) {
                free_irq(cam->irq, cam);
                cam->irq = 0;
        }

        if (cam->mmio_base) {
                iounmap((void *)cam->mmio_base);
                cam->mmio_base = 0;
        }

        if (cam->mmio_base_phys) {
                release_mem_region(cam->mmio_base_phys, cam->mmio_size);
                cam->mmio_base_phys = 0;
        }

        kfree(cam);

        return 0;
}

static struct platform_driver omap24xxcam_driver = {
        .probe   = omap24xxcam_probe,
        .remove  = omap24xxcam_remove,
#ifdef CONFIG_PM
        .suspend = omap24xxcam_suspend,
        .resume  = omap24xxcam_resume,
#endif
        .driver  = {
                .name = CAM_NAME,
                .owner = THIS_MODULE,
        },
};

/*
 *
 * Module initialisation and deinitialisation
 *
 */

static int __init omap24xxcam_init(void)
{
        return platform_driver_register(&omap24xxcam_driver);
}

static void __exit omap24xxcam_cleanup(void)
{
        platform_driver_unregister(&omap24xxcam_driver);
}

MODULE_AUTHOR("Sakari Ailus <sakari.ailus@nokia.com>");
MODULE_DESCRIPTION("OMAP24xx Video for Linux camera driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(OMAP24XXCAM_VERSION);
module_param(video_nr, int, 0);
MODULE_PARM_DESC(video_nr,
                 "Minor number for video device (-1 ==> auto assign)");
module_param(capture_mem, int, 0);
MODULE_PARM_DESC(capture_mem, "Maximum amount of memory for capture "
                 "buffers (default 4800kiB)");

module_init(omap24xxcam_init);
module_exit(omap24xxcam_cleanup);