/**
* iso_packets_buffer_init - allocates the memory for packets
* @b: the buffer structure to initialize
* @unit: the device at the other end of the stream
* @count: the number of packets
* @packet_size: the (maximum) size of a packet, in bytes
* @direction: %DMA_TO_DEVICE or %DMA_FROM_DEVICE
*/
int iso_packets_buffer_init(struct iso_packets_buffer *b, struct fw_unit *unit,
unsigned int count, unsigned int packet_size,
enum dma_data_direction direction)
{
unsigned int packets_per_page, pages;
unsigned int i, page_index, offset_in_page;
void *p;
int err;
b->packets = kmalloc(count * sizeof(*b->packets), GFP_KERNEL);
if (!b->packets) {
err = -ENOMEM;
goto error;
}
packet_size = L1_CACHE_ALIGN(packet_size);
packets_per_page = PAGE_SIZE / packet_size;
if (WARN_ON(!packets_per_page)) {
err = -EINVAL;
goto error;
}
pages = DIV_ROUND_UP(count, packets_per_page);
err = fw_iso_buffer_init(&b->iso_buffer, fw_parent_device(unit)->card,
pages, direction);
if (err < 0)
goto err_packets;
for (i = 0; i < count; ++i) {
page_index = i / packets_per_page;
p = page_address(b->iso_buffer.pages[page_index]);
offset_in_page = (i % packets_per_page) * packet_size;
b->packets[i].buffer = p + offset_in_page;
b->packets[i].offset = page_index * PAGE_SIZE + offset_in_page;
}
return 0;
err_packets:
kfree(b->packets);
error:
return err;
}
static int fw_device_op_mmap(struct file *file, struct vm_area_struct *vma)
{
struct client *client = file->private_data;
enum dma_data_direction direction;
unsigned long size;
int page_count, ret;
if (fw_device_is_shutdown(client->device))
return -ENODEV;
/* FIXME: We could support multiple buffers, but we don't. */
if (client->buffer.pages != NULL)
return -EBUSY;
if (!(vma->vm_flags & VM_SHARED))
return -EINVAL;
if (vma->vm_start & ~PAGE_MASK)
return -EINVAL;
client->vm_start = vma->vm_start;
size = vma->vm_end - vma->vm_start;
page_count = size >> PAGE_SHIFT;
if (size & ~PAGE_MASK)
return -EINVAL;
if (vma->vm_flags & VM_WRITE)
direction = DMA_TO_DEVICE;
else
direction = DMA_FROM_DEVICE;
ret = fw_iso_buffer_init(&client->buffer, client->device->card,
page_count, direction);
if (ret < 0)
return ret;
ret = fw_iso_buffer_map(&client->buffer, vma);
if (ret < 0)
fw_iso_buffer_destroy(&client->buffer, client->device->card);
return ret;
}
