V4L/DVB (9815): omap2: add OMAP2 camera driver.

Add a driver for the OMAP2 camera block. OMAP2 is used in e.g. Nokia
N800/N810 internet tablet.

This driver uses the V4L2 internal ioctl interface.

Signed-off-by: Sakari Ailus <sakari.ailus@nokia.com>
Signed-off-by: Trilok Soni <soni.trilok@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 1908 insertions, 0 deletions

diff --git a/drivers/media/video/omap24xxcam.c b/drivers/media/video/omap24xxcam.c
new file mode 100644
index 00000000000..85c3c7c92af
--- /dev/null
+++ b/drivers/media/video/omap24xxcam.c
@@ -0,0 +1,1908 @@
+/*
+ * 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/version.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+
+#include <media/v4l2-common.h>
+#include <media/v4l2-ioctl.h>
+
+#include "omap24xxcam.h"
+
+#define OMAP24XXCAM_VERSION KERNEL_VERSION(0, 0, 0)
+
+#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, "cam_fck");
+	if (IS_ERR(cam->fck)) {
+		dev_err(cam->dev, "can't get cam_fck");
+		rval = PTR_ERR(cam->fck);
+		omap24xxcam_clock_put(cam);
+		return rval;
+	}
+
+	cam->ick = clk_get(cam->dev, "cam_ick");
+	if (IS_ERR(cam->ick)) {
+		dev_err(cam->dev, "can't get cam_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 | GFP_DMA, order);
+		/* if allocation fails, try to allocate smaller amount */
+		while (page == NULL) {
+			order--;
+			page = alloc_pages(GFP_KERNEL | GFP_DMA, 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(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, 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 */
+	while (*size * *cnt > fh->cam->capture_mem)
+		(*cnt)--;
+
+	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->version = OMAP24XXCAM_VERSION;
+	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_scheduled_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;
+
+	if (a->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
+		return -EINVAL;
+
+	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;
+
+	if (a->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
+		return -EINVAL;
+
+	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++) {
+		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 inode *inode, struct file *file)
+{
+	int minor = iminor(inode);
+	struct omap24xxcam_device *cam = omap24xxcam.priv;
+	struct omap24xxcam_fh *fh;
+	struct v4l2_format format;
+
+	if (!cam || !cam->vfd || (cam->vfd->minor != minor))
+		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);
+
+	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 inode *inode, struct file *file)
+{
+	struct omap24xxcam_fh *fh = file->private_data;
+	struct omap24xxcam_device *cam = fh->cam;
+
+	atomic_inc(&cam->reset_disable);
+
+	flush_scheduled_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_scheduled_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 file_operations omap24xxcam_fops = {
+	.llseek	 = no_llseek,
+	.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->vfl_type		 = VID_TYPE_CAPTURE | VID_TYPE_CHROMAKEY;
+	vfd->fops		 = &omap24xxcam_fops;
+	vfd->minor		 = -1;
+	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");
+		vfd->minor = -1;
+		rval = -EBUSY;
+		goto err;
+	}
+
+	omap24xxcam_poweron_reset(cam);
+
+	dev_info(cam->dev, "registered device video%d\n", vfd->minor);
+
+	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 (cam->vfd->minor == -1) {
+			/*
+			 * 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 __init 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, (mem->end - mem->start) + 1,
+				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 = (mem->end - mem->start) + 1;
+
+	/* 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_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);