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- /*
- * 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@kernel.org>
- *
- * Highly based on video-buf written originally by:
- * (c) 2001,02 Gerd Knorr <kraxel@bytesex.org>
- * (c) 2006 Mauro Carvalho Chehab, <mchehab@kernel.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/mm.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@kernel.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(array_size(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(array_size(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;
- unsigned int flags = FOLL_FORCE;
- 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_array(dma->nr_pages, sizeof(struct page *),
- GFP_KERNEL);
- if (NULL == dma->pages)
- return -ENOMEM;
- if (rw == READ)
- flags |= FOLL_WRITE;
- dprintk(1, "init user [0x%lx+0x%lx => %d pages]\n",
- data, size, dma->nr_pages);
- err = get_user_pages_longterm(data & PAGE_MASK, dma->nr_pages,
- flags, dma->pages, NULL);
- if (err != dma->nr_pages) {
- dma->nr_pages = (err >= 0) ? err : 0;
- dprintk(1, "get_user_pages_longterm: 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 %p, size=%d\n",
- 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->nr_pages, 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++) {
- if (dma->direction == DMA_FROM_DEVICE)
- set_page_dirty_lock(dma->pages[i]);
- put_page(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 vm_fault_t videobuf_vm_fault(struct vm_fault *vmf)
- {
- struct vm_area_struct *vma = vmf->vma;
- struct page *page;
- dprintk(3, "fault: fault @ %08lx [vma %08lx-%08lx]\n",
- vmf->address, vma->vm_start, vma->vm_end);
- page = alloc_page(GFP_USER | __GFP_DMA32);
- if (!page)
- return VM_FAULT_OOM;
- clear_user_highpage(page, vmf->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.nr_pages, 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);
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