From: Marin Mitov Date: Fri, 30 Apr 2010 15:36:09 +0000 (+0300) Subject: Staging: Yet another (third) dt3155 driver PCI/video4linux compliant X-Git-Tag: v2.6.35-rc1~441^2^2~302 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d42bffb8990ca9e74cc1ba625ce23dda2bd8c8c5;p=pandora-kernel.git Staging: Yet another (third) dt3155 driver PCI/video4linux compliant Kernel module (device driver) for dt3155 frame grabber video4linux2 compliant (finally). Works with "xawtv -f". ====================================================== This driver is written (almost) from scratch, using the allocator developed for dt3155pci see bellow). The driver uses videobuf-dma-contig interface modified to use the above mentioned allocator instead of dma_alloc_coheren(). The first thing to do was to design a new allocator based on allocating a configurable number of 4MB chunks of memory, that latter are broken into frame buffers of 768x576 bytes kept in different FIFOs (queues). As far as the driver autoloads as a kernel module during kernel boot, the allocation of 4MB chunks succeeds. The driver keeps three FIFOs: one for 4MB chunks, one for free buffers (available for allocations) and one for buffers already allocated. Allocation/deallocation is done automatically though the video4linux videobuf subsystem (some pointers to functions are replaced by driver supplied functions). Sure, there are problems: 1. The device tested to work with "xawtv -f" either via read() method (DT3155_STREAMING not selected), or via mmap() method (DT3155_STREAMING is selected) only. This coresponds to either cap->capabilities = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_READWRITE; or cap->capabilities = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_STREAMING; but not when cap->capabilities = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_STREAMING | V4L2_CAP_READWRITE; This is because xawtv calls poll() before starting streaming, but videobuf_poll_stream() automatically starts reading if streaming is not started. This selection is made during kernel configuration (for now). 2. Works for CCIR, but should work for RS-170 (not tested) This is made also during kernel configuration. 3. Could work for multiple dt3155 frame grabbers in a PC, (private data is allocated during PCI probe() method), but is not tested due to lack of a second board. 4. Not tested on a BIG ENDIAN architecture. 5. Many others you could find .... :-) All critics, comments, suggestions are wellcome. Signed-off-by: Marin Mitov Signed-off-by: Greg Kroah-Hartman --- Reading git-diff-tree failed