--- /dev/null
+/*
+ * helper functions for SG DMA video4linux capture buffers
+ *
+ * The functions expect the hardware being able to scatter gather
+ * (i.e. the buffers are not linear in physical memory, but fragmented
+ * into PAGE_SIZE chunks). They also assume the driver does not need
+ * to touch the video data.
+ *
+ * (c) 2007 Mauro Carvalho Chehab, <mchehab@infradead.org>
+ *
+ * Highly based on video-buf written originally by:
+ * (c) 2001,02 Gerd Knorr <kraxel@bytesex.org>
+ * (c) 2006 Mauro Carvalho Chehab, <mchehab@infradead.org>
+ * (c) 2006 Ted Walther and John Sokol
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+
+#include <linux/dma-mapping.h>
+#include <linux/vmalloc.h>
+#include <linux/pagemap.h>
+#include <linux/scatterlist.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+
+#include <media/videobuf-dma-sg.h>
+
+#define MAGIC_DMABUF 0x19721112
+#define MAGIC_SG_MEM 0x17890714
+
+#define MAGIC_CHECK(is, should) \
+ if (unlikely((is) != (should))) { \
+ printk(KERN_ERR "magic mismatch: %x (expected %x)\n", \
+ is, should); \
+ BUG(); \
+ }
+
+static int debug;
+module_param(debug, int, 0644);
+
+MODULE_DESCRIPTION("helper module to manage video4linux dma sg buffers");
+MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@infradead.org>");
+MODULE_LICENSE("GPL");
+
+#define dprintk(level, fmt, arg...) \
+ if (debug >= level) \
+ printk(KERN_DEBUG "vbuf-sg: " fmt , ## arg)
+
+/* --------------------------------------------------------------------- */
+
+/*
+ * Return a scatterlist for some page-aligned vmalloc()'ed memory
+ * block (NULL on errors). Memory for the scatterlist is allocated
+ * using kmalloc. The caller must free the memory.
+ */
+static struct scatterlist *videobuf_vmalloc_to_sg(unsigned char *virt,
+ int nr_pages)
+{
+ struct scatterlist *sglist;
+ struct page *pg;
+ int i;
+
+ sglist = vzalloc(nr_pages * sizeof(*sglist));
+ if (NULL == sglist)
+ return NULL;
+ sg_init_table(sglist, nr_pages);
+ for (i = 0; i < nr_pages; i++, virt += PAGE_SIZE) {
+ pg = vmalloc_to_page(virt);
+ if (NULL == pg)
+ goto err;
+ BUG_ON(PageHighMem(pg));
+ sg_set_page(&sglist[i], pg, PAGE_SIZE, 0);
+ }
+ return sglist;
+
+err:
+ vfree(sglist);
+ return NULL;
+}
+
+/*
+ * Return a scatterlist for a an array of userpages (NULL on errors).
+ * Memory for the scatterlist is allocated using kmalloc. The caller
+ * must free the memory.
+ */
+static struct scatterlist *videobuf_pages_to_sg(struct page **pages,
+ int nr_pages, int offset, size_t size)
+{
+ struct scatterlist *sglist;
+ int i;
+
+ if (NULL == pages[0])
+ return NULL;
+ sglist = vmalloc(nr_pages * sizeof(*sglist));
+ if (NULL == sglist)
+ return NULL;
+ sg_init_table(sglist, nr_pages);
+
+ if (PageHighMem(pages[0]))
+ /* DMA to highmem pages might not work */
+ goto highmem;
+ sg_set_page(&sglist[0], pages[0],
+ min_t(size_t, PAGE_SIZE - offset, size), offset);
+ size -= min_t(size_t, PAGE_SIZE - offset, size);
+ for (i = 1; i < nr_pages; i++) {
+ if (NULL == pages[i])
+ goto nopage;
+ if (PageHighMem(pages[i]))
+ goto highmem;
+ sg_set_page(&sglist[i], pages[i], min_t(size_t, PAGE_SIZE, size), 0);
+ size -= min_t(size_t, PAGE_SIZE, size);
+ }
+ return sglist;
+
+nopage:
+ dprintk(2, "sgl: oops - no page\n");
+ vfree(sglist);
+ return NULL;
+
+highmem:
+ dprintk(2, "sgl: oops - highmem page\n");
+ vfree(sglist);
+ return NULL;
+}
+
+/* --------------------------------------------------------------------- */
+
+struct videobuf_dmabuf *videobuf_to_dma(struct videobuf_buffer *buf)
+{
+ struct videobuf_dma_sg_memory *mem = buf->priv;
+ BUG_ON(!mem);
+
+ MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
+
+ return &mem->dma;
+}
+EXPORT_SYMBOL_GPL(videobuf_to_dma);
+
+static void videobuf_dma_init(struct videobuf_dmabuf *dma)
+{
+ memset(dma, 0, sizeof(*dma));
+ dma->magic = MAGIC_DMABUF;
+}
+
+static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma,
+ int direction, unsigned long data, unsigned long size)
+{
+ unsigned long first, last;
+ int err, rw = 0;
+
+ dma->direction = direction;
+ switch (dma->direction) {
+ case DMA_FROM_DEVICE:
+ rw = READ;
+ break;
+ case DMA_TO_DEVICE:
+ rw = WRITE;
+ break;
+ default:
+ BUG();
+ }
+
+ first = (data & PAGE_MASK) >> PAGE_SHIFT;
+ last = ((data+size-1) & PAGE_MASK) >> PAGE_SHIFT;
+ dma->offset = data & ~PAGE_MASK;
+ dma->size = size;
+ dma->nr_pages = last-first+1;
+ dma->pages = kmalloc(dma->nr_pages * sizeof(struct page *), GFP_KERNEL);
+ if (NULL == dma->pages)
+ return -ENOMEM;
+
+ dprintk(1, "init user [0x%lx+0x%lx => %d pages]\n",
+ data, size, dma->nr_pages);
+
+ err = get_user_pages(current, current->mm,
+ data & PAGE_MASK, dma->nr_pages,
+ rw == READ, 1, /* force */
+ dma->pages, NULL);
+
+ if (err != dma->nr_pages) {
+ dma->nr_pages = (err >= 0) ? err : 0;
+ dprintk(1, "get_user_pages: err=%d [%d]\n", err, dma->nr_pages);
+ return err < 0 ? err : -EINVAL;
+ }
+ return 0;
+}
+
+static int videobuf_dma_init_user(struct videobuf_dmabuf *dma, int direction,
+ unsigned long data, unsigned long size)
+{
+ int ret;
+
+ down_read(¤t->mm->mmap_sem);
+ ret = videobuf_dma_init_user_locked(dma, direction, data, size);
+ up_read(¤t->mm->mmap_sem);
+
+ return ret;
+}
+
+static int videobuf_dma_init_kernel(struct videobuf_dmabuf *dma, int direction,
+ int nr_pages)
+{
+ int i;
+
+ dprintk(1, "init kernel [%d pages]\n", nr_pages);
+
+ dma->direction = direction;
+ dma->vaddr_pages = kcalloc(nr_pages, sizeof(*dma->vaddr_pages),
+ GFP_KERNEL);
+ if (!dma->vaddr_pages)
+ return -ENOMEM;
+
+ dma->dma_addr = kcalloc(nr_pages, sizeof(*dma->dma_addr), GFP_KERNEL);
+ if (!dma->dma_addr) {
+ kfree(dma->vaddr_pages);
+ return -ENOMEM;
+ }
+ for (i = 0; i < nr_pages; i++) {
+ void *addr;
+
+ addr = dma_alloc_coherent(dma->dev, PAGE_SIZE,
+ &(dma->dma_addr[i]), GFP_KERNEL);
+ if (addr == NULL)
+ goto out_free_pages;
+
+ dma->vaddr_pages[i] = virt_to_page(addr);
+ }
+ dma->vaddr = vmap(dma->vaddr_pages, nr_pages, VM_MAP | VM_IOREMAP,
+ PAGE_KERNEL);
+ if (NULL == dma->vaddr) {
+ dprintk(1, "vmalloc_32(%d pages) failed\n", nr_pages);
+ goto out_free_pages;
+ }
+
+ dprintk(1, "vmalloc is at addr 0x%08lx, size=%d\n",
+ (unsigned long)dma->vaddr,
+ nr_pages << PAGE_SHIFT);
+
+ memset(dma->vaddr, 0, nr_pages << PAGE_SHIFT);
+ dma->nr_pages = nr_pages;
+
+ return 0;
+out_free_pages:
+ while (i > 0) {
+ void *addr;
+
+ i--;
+ addr = page_address(dma->vaddr_pages[i]);
+ dma_free_coherent(dma->dev, PAGE_SIZE, addr, dma->dma_addr[i]);
+ }
+ kfree(dma->dma_addr);
+ dma->dma_addr = NULL;
+ kfree(dma->vaddr_pages);
+ dma->vaddr_pages = NULL;
+
+ return -ENOMEM;
+
+}
+
+static int videobuf_dma_init_overlay(struct videobuf_dmabuf *dma, int direction,
+ dma_addr_t addr, int nr_pages)
+{
+ dprintk(1, "init overlay [%d pages @ bus 0x%lx]\n",
+ nr_pages, (unsigned long)addr);
+ dma->direction = direction;
+
+ if (0 == addr)
+ return -EINVAL;
+
+ dma->bus_addr = addr;
+ dma->nr_pages = nr_pages;
+
+ return 0;
+}
+
+static int videobuf_dma_map(struct device *dev, struct videobuf_dmabuf *dma)
+{
+ MAGIC_CHECK(dma->magic, MAGIC_DMABUF);
+ BUG_ON(0 == dma->nr_pages);
+
+ if (dma->pages) {
+ dma->sglist = videobuf_pages_to_sg(dma->pages, dma->nr_pages,
+ dma->offset, dma->size);
+ }
+ if (dma->vaddr) {
+ dma->sglist = videobuf_vmalloc_to_sg(dma->vaddr,
+ dma->nr_pages);
+ }
+ if (dma->bus_addr) {
+ dma->sglist = vmalloc(sizeof(*dma->sglist));
+ if (NULL != dma->sglist) {
+ dma->sglen = 1;
+ sg_dma_address(&dma->sglist[0]) = dma->bus_addr
+ & PAGE_MASK;
+ dma->sglist[0].offset = dma->bus_addr & ~PAGE_MASK;
+ sg_dma_len(&dma->sglist[0]) = dma->nr_pages * PAGE_SIZE;
+ }
+ }
+ if (NULL == dma->sglist) {
+ dprintk(1, "scatterlist is NULL\n");
+ return -ENOMEM;
+ }
+ if (!dma->bus_addr) {
+ dma->sglen = dma_map_sg(dev, dma->sglist,
+ dma->nr_pages, dma->direction);
+ if (0 == dma->sglen) {
+ printk(KERN_WARNING
+ "%s: videobuf_map_sg failed\n", __func__);
+ vfree(dma->sglist);
+ dma->sglist = NULL;
+ dma->sglen = 0;
+ return -ENOMEM;
+ }
+ }
+
+ return 0;
+}
+
+int videobuf_dma_unmap(struct device *dev, struct videobuf_dmabuf *dma)
+{
+ MAGIC_CHECK(dma->magic, MAGIC_DMABUF);
+
+ if (!dma->sglen)
+ return 0;
+
+ dma_unmap_sg(dev, dma->sglist, dma->sglen, dma->direction);
+
+ vfree(dma->sglist);
+ dma->sglist = NULL;
+ dma->sglen = 0;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(videobuf_dma_unmap);
+
+int videobuf_dma_free(struct videobuf_dmabuf *dma)
+{
+ int i;
+ MAGIC_CHECK(dma->magic, MAGIC_DMABUF);
+ BUG_ON(dma->sglen);
+
+ if (dma->pages) {
+ for (i = 0; i < dma->nr_pages; i++)
+ page_cache_release(dma->pages[i]);
+ kfree(dma->pages);
+ dma->pages = NULL;
+ }
+
+ if (dma->dma_addr) {
+ for (i = 0; i < dma->nr_pages; i++) {
+ void *addr;
+
+ addr = page_address(dma->vaddr_pages[i]);
+ dma_free_coherent(dma->dev, PAGE_SIZE, addr,
+ dma->dma_addr[i]);
+ }
+ kfree(dma->dma_addr);
+ dma->dma_addr = NULL;
+ kfree(dma->vaddr_pages);
+ dma->vaddr_pages = NULL;
+ vunmap(dma->vaddr);
+ dma->vaddr = NULL;
+ }
+
+ if (dma->bus_addr)
+ dma->bus_addr = 0;
+ dma->direction = DMA_NONE;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(videobuf_dma_free);
+
+/* --------------------------------------------------------------------- */
+
+static void videobuf_vm_open(struct vm_area_struct *vma)
+{
+ struct videobuf_mapping *map = vma->vm_private_data;
+
+ dprintk(2, "vm_open %p [count=%d,vma=%08lx-%08lx]\n", map,
+ map->count, vma->vm_start, vma->vm_end);
+
+ map->count++;
+}
+
+static void videobuf_vm_close(struct vm_area_struct *vma)
+{
+ struct videobuf_mapping *map = vma->vm_private_data;
+ struct videobuf_queue *q = map->q;
+ struct videobuf_dma_sg_memory *mem;
+ int i;
+
+ dprintk(2, "vm_close %p [count=%d,vma=%08lx-%08lx]\n", map,
+ map->count, vma->vm_start, vma->vm_end);
+
+ map->count--;
+ if (0 == map->count) {
+ dprintk(1, "munmap %p q=%p\n", map, q);
+ videobuf_queue_lock(q);
+ for (i = 0; i < VIDEO_MAX_FRAME; i++) {
+ if (NULL == q->bufs[i])
+ continue;
+ mem = q->bufs[i]->priv;
+ if (!mem)
+ continue;
+
+ MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
+
+ if (q->bufs[i]->map != map)
+ continue;
+ q->bufs[i]->map = NULL;
+ q->bufs[i]->baddr = 0;
+ q->ops->buf_release(q, q->bufs[i]);
+ }
+ videobuf_queue_unlock(q);
+ kfree(map);
+ }
+ return;
+}
+
+/*
+ * Get a anonymous page for the mapping. Make sure we can DMA to that
+ * memory location with 32bit PCI devices (i.e. don't use highmem for
+ * now ...). Bounce buffers don't work very well for the data rates
+ * video capture has.
+ */
+static int videobuf_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+ struct page *page;
+
+ dprintk(3, "fault: fault @ %08lx [vma %08lx-%08lx]\n",
+ (unsigned long)vmf->virtual_address,
+ vma->vm_start, vma->vm_end);
+
+ page = alloc_page(GFP_USER | __GFP_DMA32);
+ if (!page)
+ return VM_FAULT_OOM;
+ clear_user_highpage(page, (unsigned long)vmf->virtual_address);
+ vmf->page = page;
+
+ return 0;
+}
+
+static const struct vm_operations_struct videobuf_vm_ops = {
+ .open = videobuf_vm_open,
+ .close = videobuf_vm_close,
+ .fault = videobuf_vm_fault,
+};
+
+/* ---------------------------------------------------------------------
+ * SG handlers for the generic methods
+ */
+
+/* Allocated area consists on 3 parts:
+ struct video_buffer
+ struct <driver>_buffer (cx88_buffer, saa7134_buf, ...)
+ struct videobuf_dma_sg_memory
+ */
+
+static struct videobuf_buffer *__videobuf_alloc_vb(size_t size)
+{
+ struct videobuf_dma_sg_memory *mem;
+ struct videobuf_buffer *vb;
+
+ vb = kzalloc(size + sizeof(*mem), GFP_KERNEL);
+ if (!vb)
+ return vb;
+
+ mem = vb->priv = ((char *)vb) + size;
+ mem->magic = MAGIC_SG_MEM;
+
+ videobuf_dma_init(&mem->dma);
+
+ dprintk(1, "%s: allocated at %p(%ld+%ld) & %p(%ld)\n",
+ __func__, vb, (long)sizeof(*vb), (long)size - sizeof(*vb),
+ mem, (long)sizeof(*mem));
+
+ return vb;
+}
+
+static void *__videobuf_to_vaddr(struct videobuf_buffer *buf)
+{
+ struct videobuf_dma_sg_memory *mem = buf->priv;
+ BUG_ON(!mem);
+
+ MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
+
+ return mem->dma.vaddr;
+}
+
+static int __videobuf_iolock(struct videobuf_queue *q,
+ struct videobuf_buffer *vb,
+ struct v4l2_framebuffer *fbuf)
+{
+ int err, pages;
+ dma_addr_t bus;
+ struct videobuf_dma_sg_memory *mem = vb->priv;
+ BUG_ON(!mem);
+
+ MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
+
+ if (!mem->dma.dev)
+ mem->dma.dev = q->dev;
+ else
+ WARN_ON(mem->dma.dev != q->dev);
+
+ switch (vb->memory) {
+ case V4L2_MEMORY_MMAP:
+ case V4L2_MEMORY_USERPTR:
+ if (0 == vb->baddr) {
+ /* no userspace addr -- kernel bounce buffer */
+ pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT;
+ err = videobuf_dma_init_kernel(&mem->dma,
+ DMA_FROM_DEVICE,
+ pages);
+ if (0 != err)
+ return err;
+ } else if (vb->memory == V4L2_MEMORY_USERPTR) {
+ /* dma directly to userspace */
+ err = videobuf_dma_init_user(&mem->dma,
+ DMA_FROM_DEVICE,
+ vb->baddr, vb->bsize);
+ if (0 != err)
+ return err;
+ } else {
+ /* NOTE: HACK: videobuf_iolock on V4L2_MEMORY_MMAP
+ buffers can only be called from videobuf_qbuf
+ we take current->mm->mmap_sem there, to prevent
+ locking inversion, so don't take it here */
+
+ err = videobuf_dma_init_user_locked(&mem->dma,
+ DMA_FROM_DEVICE,
+ vb->baddr, vb->bsize);
+ if (0 != err)
+ return err;
+ }
+ break;
+ case V4L2_MEMORY_OVERLAY:
+ if (NULL == fbuf)
+ return -EINVAL;
+ /* FIXME: need sanity checks for vb->boff */
+ /*
+ * Using a double cast to avoid compiler warnings when
+ * building for PAE. Compiler doesn't like direct casting
+ * of a 32 bit ptr to 64 bit integer.
+ */
+ bus = (dma_addr_t)(unsigned long)fbuf->base + vb->boff;
+ pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT;
+ err = videobuf_dma_init_overlay(&mem->dma, DMA_FROM_DEVICE,
+ bus, pages);
+ if (0 != err)
+ return err;
+ break;
+ default:
+ BUG();
+ }
+ err = videobuf_dma_map(q->dev, &mem->dma);
+ if (0 != err)
+ return err;
+
+ return 0;
+}
+
+static int __videobuf_sync(struct videobuf_queue *q,
+ struct videobuf_buffer *buf)
+{
+ struct videobuf_dma_sg_memory *mem = buf->priv;
+ BUG_ON(!mem || !mem->dma.sglen);
+
+ MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
+ MAGIC_CHECK(mem->dma.magic, MAGIC_DMABUF);
+
+ dma_sync_sg_for_cpu(q->dev, mem->dma.sglist,
+ mem->dma.sglen, mem->dma.direction);
+
+ return 0;
+}
+
+static int __videobuf_mmap_mapper(struct videobuf_queue *q,
+ struct videobuf_buffer *buf,
+ struct vm_area_struct *vma)
+{
+ struct videobuf_dma_sg_memory *mem = buf->priv;
+ struct videobuf_mapping *map;
+ unsigned int first, last, size = 0, i;
+ int retval;
+
+ retval = -EINVAL;
+
+ BUG_ON(!mem);
+ MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
+
+ /* look for first buffer to map */
+ for (first = 0; first < VIDEO_MAX_FRAME; first++) {
+ if (buf == q->bufs[first]) {
+ size = PAGE_ALIGN(q->bufs[first]->bsize);
+ break;
+ }
+ }
+
+ /* paranoia, should never happen since buf is always valid. */
+ if (!size) {
+ dprintk(1, "mmap app bug: offset invalid [offset=0x%lx]\n",
+ (vma->vm_pgoff << PAGE_SHIFT));
+ goto done;
+ }
+
+ last = first;
+
+ /* create mapping + update buffer list */
+ retval = -ENOMEM;
+ map = kmalloc(sizeof(struct videobuf_mapping), GFP_KERNEL);
+ if (NULL == map)
+ goto done;
+
+ size = 0;
+ for (i = first; i <= last; i++) {
+ if (NULL == q->bufs[i])
+ continue;
+ q->bufs[i]->map = map;
+ q->bufs[i]->baddr = vma->vm_start + size;
+ size += PAGE_ALIGN(q->bufs[i]->bsize);
+ }
+
+ map->count = 1;
+ map->q = q;
+ vma->vm_ops = &videobuf_vm_ops;
+ vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
+ vma->vm_flags &= ~VM_IO; /* using shared anonymous pages */
+ vma->vm_private_data = map;
+ dprintk(1, "mmap %p: q=%p %08lx-%08lx pgoff %08lx bufs %d-%d\n",
+ map, q, vma->vm_start, vma->vm_end, vma->vm_pgoff, first, last);
+ retval = 0;
+
+done:
+ return retval;
+}
+
+static struct videobuf_qtype_ops sg_ops = {
+ .magic = MAGIC_QTYPE_OPS,
+
+ .alloc_vb = __videobuf_alloc_vb,
+ .iolock = __videobuf_iolock,
+ .sync = __videobuf_sync,
+ .mmap_mapper = __videobuf_mmap_mapper,
+ .vaddr = __videobuf_to_vaddr,
+};
+
+void *videobuf_sg_alloc(size_t size)
+{
+ struct videobuf_queue q;
+
+ /* Required to make generic handler to call __videobuf_alloc */
+ q.int_ops = &sg_ops;
+
+ q.msize = size;
+
+ return videobuf_alloc_vb(&q);
+}
+EXPORT_SYMBOL_GPL(videobuf_sg_alloc);
+
+void videobuf_queue_sg_init(struct videobuf_queue *q,
+ const struct videobuf_queue_ops *ops,
+ struct device *dev,
+ spinlock_t *irqlock,
+ enum v4l2_buf_type type,
+ enum v4l2_field field,
+ unsigned int msize,
+ void *priv,
+ struct mutex *ext_lock)
+{
+ videobuf_queue_core_init(q, ops, dev, irqlock, type, field, msize,
+ priv, &sg_ops, ext_lock);
+}
+EXPORT_SYMBOL_GPL(videobuf_queue_sg_init);
+
Code Review / kvmfornfv.git / blobdiff