diff options
Diffstat (limited to 'drivers/media/v4l2-core/videobuf-vmalloc.c')
| -rw-r--r-- | drivers/media/v4l2-core/videobuf-vmalloc.c | 349 |
1 files changed, 349 insertions, 0 deletions
diff --git a/drivers/media/v4l2-core/videobuf-vmalloc.c b/drivers/media/v4l2-core/videobuf-vmalloc.c new file mode 100644 index 000000000000..df142580e44c --- /dev/null +++ b/drivers/media/v4l2-core/videobuf-vmalloc.c @@ -0,0 +1,349 @@ +/* + * helper functions for vmalloc 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> + * + * 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/slab.h> +#include <linux/interrupt.h> + +#include <linux/pci.h> +#include <linux/vmalloc.h> +#include <linux/pagemap.h> +#include <asm/page.h> +#include <asm/pgtable.h> + +#include <media/videobuf-vmalloc.h> + +#define MAGIC_DMABUF 0x17760309 +#define MAGIC_VMAL_MEM 0x18221223 + +#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 vmalloc buffers"); +MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@infradead.org>"); +MODULE_LICENSE("GPL"); + +#define dprintk(level, fmt, arg...) \ + if (debug >= level) \ + printk(KERN_DEBUG "vbuf-vmalloc: " fmt , ## arg) + + +/***************************************************************************/ + +static void videobuf_vm_open(struct vm_area_struct *vma) +{ + struct videobuf_mapping *map = vma->vm_private_data; + + dprintk(2, "vm_open %p [count=%u,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; + int i; + + dprintk(2, "vm_close %p [count=%u,vma=%08lx-%08lx]\n", map, + map->count, vma->vm_start, vma->vm_end); + + map->count--; + if (0 == map->count) { + struct videobuf_vmalloc_memory *mem; + + dprintk(1, "munmap %p q=%p\n", map, q); + videobuf_queue_lock(q); + + /* We need first to cancel streams, before unmapping */ + if (q->streaming) + videobuf_queue_cancel(q); + + for (i = 0; i < VIDEO_MAX_FRAME; i++) { + if (NULL == q->bufs[i]) + continue; + + if (q->bufs[i]->map != map) + continue; + + mem = q->bufs[i]->priv; + if (mem) { + /* This callback is called only if kernel has + allocated memory and this memory is mmapped. + In this case, memory should be freed, + in order to do memory unmap. + */ + + MAGIC_CHECK(mem->magic, MAGIC_VMAL_MEM); + + /* vfree is not atomic - can't be + called with IRQ's disabled + */ + dprintk(1, "%s: buf[%d] freeing (%p)\n", + __func__, i, mem->vaddr); + + vfree(mem->vaddr); + mem->vaddr = NULL; + } + + q->bufs[i]->map = NULL; + q->bufs[i]->baddr = 0; + } + + kfree(map); + + videobuf_queue_unlock(q); + } + + return; +} + +static const struct vm_operations_struct videobuf_vm_ops = { + .open = videobuf_vm_open, + .close = videobuf_vm_close, +}; + +/* --------------------------------------------------------------------- + * vmalloc 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_vmalloc_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_VMAL_MEM; + + 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 int __videobuf_iolock(struct videobuf_queue *q, + struct videobuf_buffer *vb, + struct v4l2_framebuffer *fbuf) +{ + struct videobuf_vmalloc_memory *mem = vb->priv; + int pages; + + BUG_ON(!mem); + + MAGIC_CHECK(mem->magic, MAGIC_VMAL_MEM); + + switch (vb->memory) { + case V4L2_MEMORY_MMAP: + dprintk(1, "%s memory method MMAP\n", __func__); + + /* All handling should be done by __videobuf_mmap_mapper() */ + if (!mem->vaddr) { + printk(KERN_ERR "memory is not alloced/mmapped.\n"); + return -EINVAL; + } + break; + case V4L2_MEMORY_USERPTR: + pages = PAGE_ALIGN(vb->size); + + dprintk(1, "%s memory method USERPTR\n", __func__); + + if (vb->baddr) { + printk(KERN_ERR "USERPTR is currently not supported\n"); + return -EINVAL; + } + + /* The only USERPTR currently supported is the one needed for + * read() method. + */ + + mem->vaddr = vmalloc_user(pages); + if (!mem->vaddr) { + printk(KERN_ERR "vmalloc (%d pages) failed\n", pages); + return -ENOMEM; + } + dprintk(1, "vmalloc is at addr %p (%d pages)\n", + mem->vaddr, pages); + +#if 0 + int rc; + /* Kernel userptr is used also by read() method. In this case, + there's no need to remap, since data will be copied to user + */ + if (!vb->baddr) + return 0; + + /* FIXME: to properly support USERPTR, remap should occur. + The code below won't work, since mem->vma = NULL + */ + /* Try to remap memory */ + rc = remap_vmalloc_range(mem->vma, (void *)vb->baddr, 0); + if (rc < 0) { + printk(KERN_ERR "mmap: remap failed with error %d", rc); + return -ENOMEM; + } +#endif + + break; + case V4L2_MEMORY_OVERLAY: + default: + dprintk(1, "%s memory method OVERLAY/unknown\n", __func__); + + /* Currently, doesn't support V4L2_MEMORY_OVERLAY */ + printk(KERN_ERR "Memory method currently unsupported.\n"); + return -EINVAL; + } + + return 0; +} + +static int __videobuf_mmap_mapper(struct videobuf_queue *q, + struct videobuf_buffer *buf, + struct vm_area_struct *vma) +{ + struct videobuf_vmalloc_memory *mem; + struct videobuf_mapping *map; + int retval, pages; + + dprintk(1, "%s\n", __func__); + + /* create mapping + update buffer list */ + map = kzalloc(sizeof(struct videobuf_mapping), GFP_KERNEL); + if (NULL == map) + return -ENOMEM; + + buf->map = map; + map->q = q; + + buf->baddr = vma->vm_start; + + mem = buf->priv; + BUG_ON(!mem); + MAGIC_CHECK(mem->magic, MAGIC_VMAL_MEM); + + pages = PAGE_ALIGN(vma->vm_end - vma->vm_start); + mem->vaddr = vmalloc_user(pages); + if (!mem->vaddr) { + printk(KERN_ERR "vmalloc (%d pages) failed\n", pages); + goto error; + } + dprintk(1, "vmalloc is at addr %p (%d pages)\n", mem->vaddr, pages); + + /* Try to remap memory */ + retval = remap_vmalloc_range(vma, mem->vaddr, 0); + if (retval < 0) { + printk(KERN_ERR "mmap: remap failed with error %d. ", retval); + vfree(mem->vaddr); + goto error; + } + + vma->vm_ops = &videobuf_vm_ops; + vma->vm_flags |= VM_DONTEXPAND | VM_RESERVED; + vma->vm_private_data = map; + + dprintk(1, "mmap %p: q=%p %08lx-%08lx (%lx) pgoff %08lx buf %d\n", + map, q, vma->vm_start, vma->vm_end, + (long int)buf->bsize, + vma->vm_pgoff, buf->i); + + videobuf_vm_open(vma); + + return 0; + +error: + mem = NULL; + kfree(map); + return -ENOMEM; +} + +static struct videobuf_qtype_ops qops = { + .magic = MAGIC_QTYPE_OPS, + + .alloc_vb = __videobuf_alloc_vb, + .iolock = __videobuf_iolock, + .mmap_mapper = __videobuf_mmap_mapper, + .vaddr = videobuf_to_vmalloc, +}; + +void videobuf_queue_vmalloc_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, &qops, ext_lock); +} +EXPORT_SYMBOL_GPL(videobuf_queue_vmalloc_init); + +void *videobuf_to_vmalloc(struct videobuf_buffer *buf) +{ + struct videobuf_vmalloc_memory *mem = buf->priv; + BUG_ON(!mem); + MAGIC_CHECK(mem->magic, MAGIC_VMAL_MEM); + + return mem->vaddr; +} +EXPORT_SYMBOL_GPL(videobuf_to_vmalloc); + +void videobuf_vmalloc_free(struct videobuf_buffer *buf) +{ + struct videobuf_vmalloc_memory *mem = buf->priv; + + /* mmapped memory can't be freed here, otherwise mmapped region + would be released, while still needed. In this case, the memory + release should happen inside videobuf_vm_close(). + So, it should free memory only if the memory were allocated for + read() operation. + */ + if ((buf->memory != V4L2_MEMORY_USERPTR) || buf->baddr) + return; + + if (!mem) + return; + + MAGIC_CHECK(mem->magic, MAGIC_VMAL_MEM); + + vfree(mem->vaddr); + mem->vaddr = NULL; + + return; +} +EXPORT_SYMBOL_GPL(videobuf_vmalloc_free); + |