--- /dev/null
+/*
+ * 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_DONTDUMP;
+ 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);
+
Code Review / kvmfornfv.git / blobdiff