1 files changed, 1153 insertions, 0 deletions

diff --git a/drivers/media/video/omap3isp/ispqueue.c b/drivers/media/video/omap3isp/ispqueue.c
new file mode 100644
index 000000000000..8fddc5806b0d
--- /dev/null
+++ b/drivers/media/video/omap3isp/ispqueue.c
@@ -0,0 +1,1153 @@
+/*
+ * ispqueue.c
+ *
+ * TI OMAP3 ISP - Video buffers queue handling
+ *
+ * Copyright (C) 2010 Nokia Corporation
+ *
+ * Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
+ *           Sakari Ailus <sakari.ailus@iki.fi>
+ *
+ * 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 <asm/cacheflush.h>
+#include <linux/dma-mapping.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/poll.h>
+#include <linux/scatterlist.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+
+#include "ispqueue.h"
+
+/* -----------------------------------------------------------------------------
+ * Video buffers management
+ */
+
+/*
+ * isp_video_buffer_cache_sync - Keep the buffers coherent between CPU and ISP
+ *
+ * The typical operation required here is Cache Invalidation across
+ * the (user space) buffer address range. And this _must_ be done
+ * at QBUF stage (and *only* at QBUF).
+ *
+ * We try to use optimal cache invalidation function:
+ * - dmac_map_area:
+ *    - used when the number of pages are _low_.
+ *    - it becomes quite slow as the number of pages increase.
+ *       - for 648x492 viewfinder (150 pages) it takes 1.3 ms.
+ *       - for 5 Mpix buffer (2491 pages) it takes between 25-50 ms.
+ *
+ * - flush_cache_all:
+ *    - used when the number of pages are _high_.
+ *    - time taken in the range of 500-900 us.
+ *    - has a higher penalty but, as whole dcache + icache is invalidated
+ */
+/*
+ * FIXME: dmac_inv_range crashes randomly on the user space buffer
+ *        address. Fall back to flush_cache_all for now.
+ */
+#define ISP_CACHE_FLUSH_PAGES_MAX       0
+
+static void isp_video_buffer_cache_sync(struct isp_video_buffer *buf)
+{
+        if (buf->skip_cache)
+                return;
+
+        if (buf->vbuf.m.userptr == 0 || buf->npages == 0 ||
+            buf->npages > ISP_CACHE_FLUSH_PAGES_MAX)
+                flush_cache_all();
+        else {
+                dmac_map_area((void *)buf->vbuf.m.userptr, buf->vbuf.length,
+                              DMA_FROM_DEVICE);
+                outer_inv_range(buf->vbuf.m.userptr,
+                                buf->vbuf.m.userptr + buf->vbuf.length);
+        }
+}
+
+/*
+ * isp_video_buffer_lock_vma - Prevent VMAs from being unmapped
+ *
+ * Lock the VMAs underlying the given buffer into memory. This avoids the
+ * userspace buffer mapping from being swapped out, making VIPT cache handling
+ * easier.
+ *
+ * Note that the pages will not be freed as the buffers have been locked to
+ * memory using by a call to get_user_pages(), but the userspace mapping could
+ * still disappear if the VMAs are not locked. This is caused by the memory
+ * management code trying to be as lock-less as possible, which results in the
+ * userspace mapping manager not finding out that the pages are locked under
+ * some conditions.
+ */
+static int isp_video_buffer_lock_vma(struct isp_video_buffer *buf, int lock)
+{
+        struct vm_area_struct *vma;
+        unsigned long start;
+        unsigned long end;
+        int ret = 0;
+
+        if (buf->vbuf.memory == V4L2_MEMORY_MMAP)
+                return 0;
+
+        /* We can be called from workqueue context if the current task dies to
+         * unlock the VMAs. In that case there's no current memory management
+         * context so unlocking can't be performed, but the VMAs have been or
+         * are getting destroyed anyway so it doesn't really matter.
+         */
+        if (!current || !current->mm)
+                return lock ? -EINVAL : 0;
+
+        start = buf->vbuf.m.userptr;
+        end = buf->vbuf.m.userptr + buf->vbuf.length - 1;
+
+        down_write(&current->mm->mmap_sem);
+        spin_lock(&current->mm->page_table_lock);
+
+        do {
+                vma = find_vma(current->mm, start);
+                if (vma == NULL) {
+                        ret = -EFAULT;
+                        goto out;
+                }
+
+                if (lock)
+                        vma->vm_flags |= VM_LOCKED;
+                else
+                        vma->vm_flags &= ~VM_LOCKED;
+
+                start = vma->vm_end + 1;
+        } while (vma->vm_end < end);
+
+        if (lock)
+                buf->vm_flags |= VM_LOCKED;
+        else
+                buf->vm_flags &= ~VM_LOCKED;
+
+out:
+        spin_unlock(&current->mm->page_table_lock);
+        up_write(&current->mm->mmap_sem);
+        return ret;
+}
+
+/*
+ * isp_video_buffer_sglist_kernel - Build a scatter list for a vmalloc'ed buffer
+ *
+ * Iterate over the vmalloc'ed area and create a scatter list entry for every
+ * page.
+ */
+static int isp_video_buffer_sglist_kernel(struct isp_video_buffer *buf)
+{
+        struct scatterlist *sglist;
+        unsigned int npages;
+        unsigned int i;
+        void *addr;
+
+        addr = buf->vaddr;
+        npages = PAGE_ALIGN(buf->vbuf.length) >> PAGE_SHIFT;
+
+        sglist = vmalloc(npages * sizeof(*sglist));
+        if (sglist == NULL)
+                return -ENOMEM;
+
+        sg_init_table(sglist, npages);
+
+        for (i = 0; i < npages; ++i, addr += PAGE_SIZE) {
+                struct page *page = vmalloc_to_page(addr);
+
+                if (page == NULL || PageHighMem(page)) {
+                        vfree(sglist);
+                        return -EINVAL;
+                }
+
+                sg_set_page(&sglist[i], page, PAGE_SIZE, 0);
+        }
+
+        buf->sglen = npages;
+        buf->sglist = sglist;
+
+        return 0;
+}
+
+/*
+ * isp_video_buffer_sglist_user - Build a scatter list for a userspace buffer
+ *
+ * Walk the buffer pages list and create a 1:1 mapping to a scatter list.
+ */
+static int isp_video_buffer_sglist_user(struct isp_video_buffer *buf)
+{
+        struct scatterlist *sglist;
+        unsigned int offset = buf->offset;
+        unsigned int i;
+
+        sglist = vmalloc(buf->npages * sizeof(*sglist));
+        if (sglist == NULL)
+                return -ENOMEM;
+
+        sg_init_table(sglist, buf->npages);
+
+        for (i = 0; i < buf->npages; ++i) {
+                if (PageHighMem(buf->pages[i])) {
+                        vfree(sglist);
+                        return -EINVAL;
+                }
+
+                sg_set_page(&sglist[i], buf->pages[i], PAGE_SIZE - offset,
+                            offset);
+                offset = 0;
+        }
+
+        buf->sglen = buf->npages;
+        buf->sglist = sglist;
+
+        return 0;
+}
+
+/*
+ * isp_video_buffer_sglist_pfnmap - Build a scatter list for a VM_PFNMAP buffer
+ *
+ * Create a scatter list of physically contiguous pages starting at the buffer
+ * memory physical address.
+ */
+static int isp_video_buffer_sglist_pfnmap(struct isp_video_buffer *buf)
+{
+        struct scatterlist *sglist;
+        unsigned int offset = buf->offset;
+        unsigned long pfn = buf->paddr >> PAGE_SHIFT;
+        unsigned int i;
+
+        sglist = vmalloc(buf->npages * sizeof(*sglist));
+        if (sglist == NULL)
+                return -ENOMEM;
+
+        sg_init_table(sglist, buf->npages);
+
+        for (i = 0; i < buf->npages; ++i, ++pfn) {
+                sg_set_page(&sglist[i], pfn_to_page(pfn), PAGE_SIZE - offset,
+                            offset);
+                /* PFNMAP buffers will not get DMA-mapped, set the DMA address
+                 * manually.
+                 */
+                sg_dma_address(&sglist[i]) = (pfn << PAGE_SHIFT) + offset;
+                offset = 0;
+        }
+
+        buf->sglen = buf->npages;
+        buf->sglist = sglist;
+
+        return 0;
+}
+
+/*
+ * isp_video_buffer_cleanup - Release pages for a userspace VMA.
+ *
+ * Release pages locked by a call isp_video_buffer_prepare_user and free the
+ * pages table.
+ */
+static void isp_video_buffer_cleanup(struct isp_video_buffer *buf)
+{
+        enum dma_data_direction direction;
+        unsigned int i;
+
+        if (buf->queue->ops->buffer_cleanup)
+                buf->queue->ops->buffer_cleanup(buf);
+
+        if (!(buf->vm_flags & VM_PFNMAP)) {
+                direction = buf->vbuf.type == V4L2_BUF_TYPE_VIDEO_CAPTURE
+                          ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
+                dma_unmap_sg(buf->queue->dev, buf->sglist, buf->sglen,
+                             direction);
+        }
+
+        vfree(buf->sglist);
+        buf->sglist = NULL;
+        buf->sglen = 0;
+
+        if (buf->pages != NULL) {
+                isp_video_buffer_lock_vma(buf, 0);
+
+                for (i = 0; i < buf->npages; ++i)
+                        page_cache_release(buf->pages[i]);
+
+                vfree(buf->pages);
+                buf->pages = NULL;
+        }
+
+        buf->npages = 0;
+        buf->skip_cache = false;
+}
+
+/*
+ * isp_video_buffer_prepare_user - Pin userspace VMA pages to memory.
+ *
+ * This function creates a list of pages for a userspace VMA. The number of
+ * pages is first computed based on the buffer size, and pages are then
+ * retrieved by a call to get_user_pages.
+ *
+ * Pages are pinned to memory by get_user_pages, making them available for DMA
+ * transfers. However, due to memory management optimization, it seems the
+ * get_user_pages doesn't guarantee that the pinned pages will not be written
+ * to swap and removed from the userspace mapping(s). When this happens, a page
+ * fault can be generated when accessing those unmapped pages.
+ *
+ * If the fault is triggered by a page table walk caused by VIPT cache
+ * management operations, the page fault handler might oops if the MM semaphore
+ * is held, as it can't handle kernel page faults in that case. To fix that, a
+ * fixup entry needs to be added to the cache management code, or the userspace
+ * VMA must be locked to avoid removing pages from the userspace mapping in the
+ * first place.
+ *
+ * If the number of pages retrieved is smaller than the number required by the
+ * buffer size, the function returns -EFAULT.
+ */
+static int isp_video_buffer_prepare_user(struct isp_video_buffer *buf)
+{
+        unsigned long data;
+        unsigned int first;
+        unsigned int last;
+        int ret;
+
+        data = buf->vbuf.m.userptr;
+        first = (data & PAGE_MASK) >> PAGE_SHIFT;
+        last = ((data + buf->vbuf.length - 1) & PAGE_MASK) >> PAGE_SHIFT;
+
+        buf->offset = data & ~PAGE_MASK;
+        buf->npages = last - first + 1;
+        buf->pages = vmalloc(buf->npages * sizeof(buf->pages[0]));
+        if (buf->pages == NULL)
+                return -ENOMEM;
+
+        down_read(&current->mm->mmap_sem);
+        ret = get_user_pages(current, current->mm, data & PAGE_MASK,
+                             buf->npages,
+                             buf->vbuf.type == V4L2_BUF_TYPE_VIDEO_CAPTURE, 0,
+                             buf->pages, NULL);
+        up_read(&current->mm->mmap_sem);
+
+        if (ret != buf->npages) {
+                buf->npages = ret;
+                isp_video_buffer_cleanup(buf);
+                return -EFAULT;
+        }
+
+        ret = isp_video_buffer_lock_vma(buf, 1);
+        if (ret < 0)
+                isp_video_buffer_cleanup(buf);
+
+        return ret;
+}
+
+/*
+ * isp_video_buffer_prepare_pfnmap - Validate a VM_PFNMAP userspace buffer
+ *
+ * Userspace VM_PFNMAP buffers are supported only if they are contiguous in
+ * memory and if they span a single VMA.
+ *
+ * Return 0 if the buffer is valid, or -EFAULT otherwise.
+ */
+static int isp_video_buffer_prepare_pfnmap(struct isp_video_buffer *buf)
+{
+        struct vm_area_struct *vma;
+        unsigned long prev_pfn;
+        unsigned long this_pfn;
+        unsigned long start;
+        unsigned long end;
+        dma_addr_t pa;
+        int ret = -EFAULT;
+
+        start = buf->vbuf.m.userptr;
+        end = buf->vbuf.m.userptr + buf->vbuf.length - 1;
+
+        buf->offset = start & ~PAGE_MASK;
+        buf->npages = (end >> PAGE_SHIFT) - (start >> PAGE_SHIFT) + 1;
+        buf->pages = NULL;
+
+        down_read(&current->mm->mmap_sem);
+        vma = find_vma(current->mm, start);
+        if (vma == NULL || vma->vm_end < end)
+                goto done;
+
+        for (prev_pfn = 0; start <= end; start += PAGE_SIZE) {
+                ret = follow_pfn(vma, start, &this_pfn);
+                if (ret)
+                        goto done;
+
+                if (prev_pfn == 0)
+                        pa = this_pfn << PAGE_SHIFT;
+                else if (this_pfn != prev_pfn + 1) {
+                        ret = -EFAULT;
+                        goto done;
+                }
+
+                prev_pfn = this_pfn;
+        }
+
+        buf->paddr = pa + buf->offset;
+        ret = 0;
+
+done:
+        up_read(&current->mm->mmap_sem);
+        return ret;
+}
+
+/*
+ * isp_video_buffer_prepare_vm_flags - Get VMA flags for a userspace address
+ *
+ * This function locates the VMAs for the buffer's userspace address and checks
+ * that their flags match. The onlflag that we need to care for at the moment is
+ * VM_PFNMAP.
+ *
+ * The buffer vm_flags field is set to the first VMA flags.
+ *
+ * Return -EFAULT if no VMA can be found for part of the buffer, or if the VMAs
+ * have incompatible flags.
+ */
+static int isp_video_buffer_prepare_vm_flags(struct isp_video_buffer *buf)
+{
+        struct vm_area_struct *vma;
+        pgprot_t vm_page_prot;
+        unsigned long start;
+        unsigned long end;
+        int ret = -EFAULT;
+
+        start = buf->vbuf.m.userptr;
+        end = buf->vbuf.m.userptr + buf->vbuf.length - 1;
+
+        down_read(&current->mm->mmap_sem);
+
+        do {
+                vma = find_vma(current->mm, start);
+                if (vma == NULL)
+                        goto done;
+
+                if (start == buf->vbuf.m.userptr) {
+                        buf->vm_flags = vma->vm_flags;
+                        vm_page_prot = vma->vm_page_prot;
+                }
+
+                if ((buf->vm_flags ^ vma->vm_flags) & VM_PFNMAP)
+                        goto done;
+
+                if (vm_page_prot != vma->vm_page_prot)
+                        goto done;
+
+                start = vma->vm_end + 1;
+        } while (vma->vm_end < end);
+
+        /* Skip cache management to enhance performances for non-cached or
+         * write-combining buffers.
+         */
+        if (vm_page_prot == pgprot_noncached(vm_page_prot) ||
+            vm_page_prot == pgprot_writecombine(vm_page_prot))
+                buf->skip_cache = true;
+
+        ret = 0;
+
+done:
+        up_read(&current->mm->mmap_sem);
+        return ret;
+}
+
+/*
+ * isp_video_buffer_prepare - Make a buffer ready for operation
+ *
+ * Preparing a buffer involves:
+ *
+ * - validating VMAs (userspace buffers only)
+ * - locking pages and VMAs into memory (userspace buffers only)
+ * - building page and scatter-gather lists
+ * - mapping buffers for DMA operation
+ * - performing driver-specific preparation
+ *
+ * The function must be called in userspace context with a valid mm context
+ * (this excludes cleanup paths such as sys_close when the userspace process
+ * segfaults).
+ */
+static int isp_video_buffer_prepare(struct isp_video_buffer *buf)
+{
+        enum dma_data_direction direction;
+        int ret;
+
+        switch (buf->vbuf.memory) {
+        case V4L2_MEMORY_MMAP:
+                ret = isp_video_buffer_sglist_kernel(buf);
+                break;
+
+        case V4L2_MEMORY_USERPTR:
+                ret = isp_video_buffer_prepare_vm_flags(buf);
+                if (ret < 0)
+                        return ret;
+
+                if (buf->vm_flags & VM_PFNMAP) {
+                        ret = isp_video_buffer_prepare_pfnmap(buf);
+                        if (ret < 0)
+                                return ret;
+
+                        ret = isp_video_buffer_sglist_pfnmap(buf);
+                } else {
+                        ret = isp_video_buffer_prepare_user(buf);
+                        if (ret < 0)
+                                return ret;
+
+                        ret = isp_video_buffer_sglist_user(buf);
+                }
+                break;
+
+        default:
+                return -EINVAL;
+        }
+
+        if (ret < 0)
+                goto done;
+
+        if (!(buf->vm_flags & VM_PFNMAP)) {
+                direction = buf->vbuf.type == V4L2_BUF_TYPE_VIDEO_CAPTURE
+                          ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
+                ret = dma_map_sg(buf->queue->dev, buf->sglist, buf->sglen,
+                                 direction);
+                if (ret != buf->sglen) {
+                        ret = -EFAULT;
+                        goto done;
+                }
+        }
+
+        if (buf->queue->ops->buffer_prepare)
+                ret = buf->queue->ops->buffer_prepare(buf);
+
+done:
+        if (ret < 0) {
+                isp_video_buffer_cleanup(buf);
+                return ret;
+        }
+
+        return ret;
+}
+
+/*
+ * isp_video_queue_query - Query the status of a given buffer
+ *
+ * Locking: must be called with the queue lock held.
+ */
+static void isp_video_buffer_query(struct isp_video_buffer *buf,
+                                   struct v4l2_buffer *vbuf)
+{
+        memcpy(vbuf, &buf->vbuf, sizeof(*vbuf));
+
+        if (buf->vma_use_count)
+                vbuf->flags |= V4L2_BUF_FLAG_MAPPED;
+
+        switch (buf->state) {
+        case ISP_BUF_STATE_ERROR:
+                vbuf->flags |= V4L2_BUF_FLAG_ERROR;
+        case ISP_BUF_STATE_DONE:
+                vbuf->flags |= V4L2_BUF_FLAG_DONE;
+        case ISP_BUF_STATE_QUEUED:
+        case ISP_BUF_STATE_ACTIVE:
+                vbuf->flags |= V4L2_BUF_FLAG_QUEUED;
+                break;
+        case ISP_BUF_STATE_IDLE:
+        default:
+                break;
+        }
+}
+
+/*
+ * isp_video_buffer_wait - Wait for a buffer to be ready
+ *
+ * In non-blocking mode, return immediately with 0 if the buffer is ready or
+ * -EAGAIN if the buffer is in the QUEUED or ACTIVE state.
+ *
+ * In blocking mode, wait (interruptibly but with no timeout) on the buffer wait
+ * queue using the same condition.
+ */
+static int isp_video_buffer_wait(struct isp_video_buffer *buf, int nonblocking)
+{
+        if (nonblocking) {
+                return (buf->state != ISP_BUF_STATE_QUEUED &&
+                        buf->state != ISP_BUF_STATE_ACTIVE)
+                        ? 0 : -EAGAIN;
+        }
+
+        return wait_event_interruptible(buf->wait,
+                buf->state != ISP_BUF_STATE_QUEUED &&
+                buf->state != ISP_BUF_STATE_ACTIVE);
+}
+
+/* -----------------------------------------------------------------------------
+ * Queue management
+ */
+
+/*
+ * isp_video_queue_free - Free video buffers memory
+ *
+ * Buffers can only be freed if the queue isn't streaming and if no buffer is
+ * mapped to userspace. Return -EBUSY if those conditions aren't statisfied.
+ *
+ * This function must be called with the queue lock held.
+ */
+static int isp_video_queue_free(struct isp_video_queue *queue)
+{
+        unsigned int i;
+
+        if (queue->streaming)
+                return -EBUSY;
+
+        for (i = 0; i < queue->count; ++i) {
+                if (queue->buffers[i]->vma_use_count != 0)
+                        return -EBUSY;
+        }
+
+        for (i = 0; i < queue->count; ++i) {
+                struct isp_video_buffer *buf = queue->buffers[i];
+
+                isp_video_buffer_cleanup(buf);
+
+                vfree(buf->vaddr);
+                buf->vaddr = NULL;
+
+                kfree(buf);
+                queue->buffers[i] = NULL;
+        }
+
+        INIT_LIST_HEAD(&queue->queue);
+        queue->count = 0;
+        return 0;
+}
+
+/*
+ * isp_video_queue_alloc - Allocate video buffers memory
+ *
+ * This function must be called with the queue lock held.
+ */
+static int isp_video_queue_alloc(struct isp_video_queue *queue,
+                                 unsigned int nbuffers,
+                                 unsigned int size, enum v4l2_memory memory)
+{
+        struct isp_video_buffer *buf;
+        unsigned int i;
+        void *mem;
+        int ret;
+
+        /* Start by freeing the buffers. */
+        ret = isp_video_queue_free(queue);
+        if (ret < 0)
+                return ret;
+
+        /* Bail out of no buffers should be allocated. */
+        if (nbuffers == 0)
+                return 0;
+
+        /* Initialize the allocated buffers. */
+        for (i = 0; i < nbuffers; ++i) {
+                buf = kzalloc(queue->bufsize, GFP_KERNEL);
+                if (buf == NULL)
+                        break;
+
+                if (memory == V4L2_MEMORY_MMAP) {
+                        /* Allocate video buffers memory for mmap mode. Align
+                         * the size to the page size.
+                         */
+                        mem = vmalloc_32_user(PAGE_ALIGN(size));
+                        if (mem == NULL) {
+                                kfree(buf);
+                                break;
+                        }
+
+                        buf->vbuf.m.offset = i * PAGE_ALIGN(size);
+                        buf->vaddr = mem;
+                }
+
+                buf->vbuf.index = i;
+                buf->vbuf.length = size;
+                buf->vbuf.type = queue->type;
+                buf->vbuf.field = V4L2_FIELD_NONE;
+                buf->vbuf.memory = memory;
+
+                buf->queue = queue;
+                init_waitqueue_head(&buf->wait);
+
+                queue->buffers[i] = buf;
+        }
+
+        if (i == 0)
+                return -ENOMEM;
+
+        queue->count = i;
+        return nbuffers;
+}
+
+/**
+ * omap3isp_video_queue_cleanup - Clean up the video buffers queue
+ * @queue: Video buffers queue
+ *
+ * Free all allocated resources and clean up the video buffers queue. The queue
+ * must not be busy (no ongoing video stream) and buffers must have been
+ * unmapped.
+ *
+ * Return 0 on success or -EBUSY if the queue is busy or buffers haven't been
+ * unmapped.
+ */
+int omap3isp_video_queue_cleanup(struct isp_video_queue *queue)
+{
+        return isp_video_queue_free(queue);
+}
+
+/**
+ * omap3isp_video_queue_init - Initialize the video buffers queue
+ * @queue: Video buffers queue
+ * @type: V4L2 buffer type (capture or output)
+ * @ops: Driver-specific queue operations
+ * @dev: Device used for DMA operations
+ * @bufsize: Size of the driver-specific buffer structure
+ *
+ * Initialize the video buffers queue with the supplied parameters.
+ *
+ * The queue type must be one of V4L2_BUF_TYPE_VIDEO_CAPTURE or
+ * V4L2_BUF_TYPE_VIDEO_OUTPUT. Other buffer types are not supported yet.
+ *
+ * Buffer objects will be allocated using the given buffer size to allow room
+ * for driver-specific fields. Driver-specific buffer structures must start
+ * with a struct isp_video_buffer field. Drivers with no driver-specific buffer
+ * structure must pass the size of the isp_video_buffer structure in the bufsize
+ * parameter.
+ *
+ * Return 0 on success.
+ */
+int omap3isp_video_queue_init(struct isp_video_queue *queue,
+                              enum v4l2_buf_type type,
+                              const struct isp_video_queue_operations *ops,
+                              struct device *dev, unsigned int bufsize)
+{
+        INIT_LIST_HEAD(&queue->queue);
+        mutex_init(&queue->lock);
+        spin_lock_init(&queue->irqlock);
+
+        queue->type = type;
+        queue->ops = ops;
+        queue->dev = dev;
+        queue->bufsize = bufsize;
+
+        return 0;
+}
+
+/* -----------------------------------------------------------------------------
+ * V4L2 operations
+ */
+
+/**
+ * omap3isp_video_queue_reqbufs - Allocate video buffers memory
+ *
+ * This function is intended to be used as a VIDIOC_REQBUFS ioctl handler. It
+ * allocated video buffer objects and, for MMAP buffers, buffer memory.
+ *
+ * If the number of buffers is 0, all buffers are freed and the function returns
+ * without performing any allocation.
+ *
+ * If the number of buffers is not 0, currently allocated buffers (if any) are
+ * freed and the requested number of buffers are allocated. Depending on
+ * driver-specific requirements and on memory availability, a number of buffer
+ * smaller or bigger than requested can be allocated. This isn't considered as
+ * an error.
+ *
+ * Return 0 on success or one of the following error codes:
+ *
+ * -EINVAL if the buffer type or index are invalid
+ * -EBUSY if the queue is busy (streaming or buffers mapped)
+ * -ENOMEM if the buffers can't be allocated due to an out-of-memory condition
+ */
+int omap3isp_video_queue_reqbufs(struct isp_video_queue *queue,
+                                 struct v4l2_requestbuffers *rb)
+{
+        unsigned int nbuffers = rb->count;
+        unsigned int size;
+        int ret;
+
+        if (rb->type != queue->type)
+                return -EINVAL;
+
+        queue->ops->queue_prepare(queue, &nbuffers, &size);
+        if (size == 0)
+                return -EINVAL;
+
+        nbuffers = min_t(unsigned int, nbuffers, ISP_VIDEO_MAX_BUFFERS);
+
+        mutex_lock(&queue->lock);
+
+        ret = isp_video_queue_alloc(queue, nbuffers, size, rb->memory);
+        if (ret < 0)
+                goto done;
+
+        rb->count = ret;
+        ret = 0;
+
+done:
+        mutex_unlock(&queue->lock);
+        return ret;
+}
+
+/**
+ * omap3isp_video_queue_querybuf - Query the status of a buffer in a queue
+ *
+ * This function is intended to be used as a VIDIOC_QUERYBUF ioctl handler. It
+ * returns the status of a given video buffer.
+ *
+ * Return 0 on success or -EINVAL if the buffer type or index are invalid.
+ */
+int omap3isp_video_queue_querybuf(struct isp_video_queue *queue,
+                                  struct v4l2_buffer *vbuf)
+{
+        struct isp_video_buffer *buf;
+        int ret = 0;
+
+        if (vbuf->type != queue->type)
+                return -EINVAL;
+
+        mutex_lock(&queue->lock);
+
+        if (vbuf->index >= queue->count) {
+                ret = -EINVAL;
+                goto done;
+        }
+
+        buf = queue->buffers[vbuf->index];
+        isp_video_buffer_query(buf, vbuf);
+
+done:
+        mutex_unlock(&queue->lock);
+        return ret;
+}
+
+/**
+ * omap3isp_video_queue_qbuf - Queue a buffer
+ *
+ * This function is intended to be used as a VIDIOC_QBUF ioctl handler.
+ *
+ * The v4l2_buffer structure passed from userspace is first sanity tested. If
+ * sane, the buffer is then processed and added to the main queue and, if the
+ * queue is streaming, to the IRQ queue.
+ *
+ * Before being enqueued, USERPTR buffers are checked for address changes. If
+ * the buffer has a different userspace address, the old memory area is unlocked
+ * and the new memory area is locked.
+ */
+int omap3isp_video_queue_qbuf(struct isp_video_queue *queue,
+                              struct v4l2_buffer *vbuf)
+{
+        struct isp_video_buffer *buf;
+        unsigned long flags;
+        int ret = -EINVAL;
+
+        if (vbuf->type != queue->type)
+                goto done;
+
+        mutex_lock(&queue->lock);
+
+        if (vbuf->index >= queue->count)
+                goto done;
+
+        buf = queue->buffers[vbuf->index];
+
+        if (vbuf->memory != buf->vbuf.memory)
+                goto done;
+
+        if (buf->state != ISP_BUF_STATE_IDLE)
+                goto done;
+
+        if (vbuf->memory == V4L2_MEMORY_USERPTR &&
+            vbuf->m.userptr != buf->vbuf.m.userptr) {
+                isp_video_buffer_cleanup(buf);
+                buf->vbuf.m.userptr = vbuf->m.userptr;
+                buf->prepared = 0;
+        }
+
+        if (!buf->prepared) {
+                ret = isp_video_buffer_prepare(buf);
+                if (ret < 0)
+                        goto done;
+                buf->prepared = 1;
+        }
+
+        isp_video_buffer_cache_sync(buf);
+
+        buf->state = ISP_BUF_STATE_QUEUED;
+        list_add_tail(&buf->stream, &queue->queue);
+
+        if (queue->streaming) {
+                spin_lock_irqsave(&queue->irqlock, flags);
+                queue->ops->buffer_queue(buf);
+                spin_unlock_irqrestore(&queue->irqlock, flags);
+        }
+
+        ret = 0;
+
+done:
+        mutex_unlock(&queue->lock);
+        return ret;
+}
+
+/**
+ * omap3isp_video_queue_dqbuf - Dequeue a buffer
+ *
+ * This function is intended to be used as a VIDIOC_DQBUF ioctl handler.
+ *
+ * The v4l2_buffer structure passed from userspace is first sanity tested. If
+ * sane, the buffer is then processed and added to the main queue and, if the
+ * queue is streaming, to the IRQ queue.
+ *
+ * Before being enqueued, USERPTR buffers are checked for address changes. If
+ * the buffer has a different userspace address, the old memory area is unlocked
+ * and the new memory area is locked.
+ */
+int omap3isp_video_queue_dqbuf(struct isp_video_queue *queue,
+                               struct v4l2_buffer *vbuf, int nonblocking)
+{
+        struct isp_video_buffer *buf;
+        int ret;
+
+        if (vbuf->type != queue->type)
+                return -EINVAL;
+
+        mutex_lock(&queue->lock);
+
+        if (list_empty(&queue->queue)) {
+                ret = -EINVAL;
+                goto done;
+        }
+
+        buf = list_first_entry(&queue->queue, struct isp_video_buffer, stream);
+        ret = isp_video_buffer_wait(buf, nonblocking);
+        if (ret < 0)
+                goto done;
+
+        list_del(&buf->stream);
+
+        isp_video_buffer_query(buf, vbuf);
+        buf->state = ISP_BUF_STATE_IDLE;
+        vbuf->flags &= ~V4L2_BUF_FLAG_QUEUED;
+
+done:
+        mutex_unlock(&queue->lock);
+        return ret;
+}
+
+/**
+ * omap3isp_video_queue_streamon - Start streaming
+ *
+ * This function is intended to be used as a VIDIOC_STREAMON ioctl handler. It
+ * starts streaming on the queue and calls the buffer_queue operation for all
+ * queued buffers.
+ *
+ * Return 0 on success.
+ */
+int omap3isp_video_queue_streamon(struct isp_video_queue *queue)
+{
+        struct isp_video_buffer *buf;
+        unsigned long flags;
+
+        mutex_lock(&queue->lock);
+
+        if (queue->streaming)
+                goto done;
+
+        queue->streaming = 1;
+
+        spin_lock_irqsave(&queue->irqlock, flags);
+        list_for_each_entry(buf, &queue->queue, stream)
+                queue->ops->buffer_queue(buf);
+        spin_unlock_irqrestore(&queue->irqlock, flags);
+
+done:
+        mutex_unlock(&queue->lock);
+        return 0;
+}
+
+/**
+ * omap3isp_video_queue_streamoff - Stop streaming
+ *
+ * This function is intended to be used as a VIDIOC_STREAMOFF ioctl handler. It
+ * stops streaming on the queue and wakes up all the buffers.
+ *
+ * Drivers must stop the hardware and synchronize with interrupt handlers and/or
+ * delayed works before calling this function to make sure no buffer will be
+ * touched by the driver and/or hardware.
+ */
+void omap3isp_video_queue_streamoff(struct isp_video_queue *queue)
+{
+        struct isp_video_buffer *buf;
+        unsigned long flags;
+        unsigned int i;
+
+        mutex_lock(&queue->lock);
+
+        if (!queue->streaming)
+                goto done;
+
+        queue->streaming = 0;
+
+        spin_lock_irqsave(&queue->irqlock, flags);
+        for (i = 0; i < queue->count; ++i) {
+                buf = queue->buffers[i];
+
+                if (buf->state == ISP_BUF_STATE_ACTIVE)
+                        wake_up(&buf->wait);
+
+                buf->state = ISP_BUF_STATE_IDLE;
+        }
+        spin_unlock_irqrestore(&queue->irqlock, flags);
+
+        INIT_LIST_HEAD(&queue->queue);
+
+done:
+        mutex_unlock(&queue->lock);
+}
+
+/**
+ * omap3isp_video_queue_discard_done - Discard all buffers marked as DONE
+ *
+ * This function is intended to be used with suspend/resume operations. It
+ * discards all 'done' buffers as they would be too old to be requested after
+ * resume.
+ *
+ * Drivers must stop the hardware and synchronize with interrupt handlers and/or
+ * delayed works before calling this function to make sure no buffer will be
+ * touched by the driver and/or hardware.
+ */
+void omap3isp_video_queue_discard_done(struct isp_video_queue *queue)
+{
+        struct isp_video_buffer *buf;
+        unsigned int i;
+
+        mutex_lock(&queue->lock);
+
+        if (!queue->streaming)
+                goto done;
+
+        for (i = 0; i < queue->count; ++i) {
+                buf = queue->buffers[i];
+
+                if (buf->state == ISP_BUF_STATE_DONE)
+                        buf->state = ISP_BUF_STATE_ERROR;
+        }
+
+done:
+        mutex_unlock(&queue->lock);
+}
+
+static void isp_video_queue_vm_open(struct vm_area_struct *vma)
+{
+        struct isp_video_buffer *buf = vma->vm_private_data;
+
+        buf->vma_use_count++;
+}
+
+static void isp_video_queue_vm_close(struct vm_area_struct *vma)
+{
+        struct isp_video_buffer *buf = vma->vm_private_data;
+
+        buf->vma_use_count--;
+}
+
+static const struct vm_operations_struct isp_video_queue_vm_ops = {
+        .open = isp_video_queue_vm_open,
+        .close = isp_video_queue_vm_close,
+};
+
+/**
+ * omap3isp_video_queue_mmap - Map buffers to userspace
+ *
+ * This function is intended to be used as an mmap() file operation handler. It
+ * maps a buffer to userspace based on the VMA offset.
+ *
+ * Only buffers of memory type MMAP are supported.
+ */
+int omap3isp_video_queue_mmap(struct isp_video_queue *queue,
+                         struct vm_area_struct *vma)
+{
+        struct isp_video_buffer *uninitialized_var(buf);
+        unsigned long size;
+        unsigned int i;
+        int ret = 0;
+
+        mutex_lock(&queue->lock);
+
+        for (i = 0; i < queue->count; ++i) {
+                buf = queue->buffers[i];
+                if ((buf->vbuf.m.offset >> PAGE_SHIFT) == vma->vm_pgoff)
+                        break;
+        }
+
+        if (i == queue->count) {
+                ret = -EINVAL;
+                goto done;
+        }
+
+        size = vma->vm_end - vma->vm_start;
+
+        if (buf->vbuf.memory != V4L2_MEMORY_MMAP ||
+            size != PAGE_ALIGN(buf->vbuf.length)) {
+                ret = -EINVAL;
+                goto done;
+        }
+
+        ret = remap_vmalloc_range(vma, buf->vaddr, 0);
+        if (ret < 0)
+                goto done;
+
+        vma->vm_ops = &isp_video_queue_vm_ops;
+        vma->vm_private_data = buf;
+        isp_video_queue_vm_open(vma);
+
+done:
+        mutex_unlock(&queue->lock);
+        return ret;
+}
+
+/**
+ * omap3isp_video_queue_poll - Poll video queue state
+ *
+ * This function is intended to be used as a poll() file operation handler. It
+ * polls the state of the video buffer at the front of the queue and returns an
+ * events mask.
+ *
+ * If no buffer is present at the front of the queue, POLLERR is returned.
+ */
+unsigned int omap3isp_video_queue_poll(struct isp_video_queue *queue,
+                                       struct file *file, poll_table *wait)
+{
+        struct isp_video_buffer *buf;
+        unsigned int mask = 0;
+
+        mutex_lock(&queue->lock);
+        if (list_empty(&queue->queue)) {
+                mask |= POLLERR;
+                goto done;
+        }
+        buf = list_first_entry(&queue->queue, struct isp_video_buffer, stream);
+
+        poll_wait(file, &buf->wait, wait);
+        if (buf->state == ISP_BUF_STATE_DONE ||
+            buf->state == ISP_BUF_STATE_ERROR) {
+                if (queue->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
+                        mask |= POLLIN | POLLRDNORM;
+                else
+                        mask |= POLLOUT | POLLWRNORM;
+        }
+
+done:
+        mutex_unlock(&queue->lock);
+        return mask;
+}