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2015-01-17staging: comedi: ni_at_a2150: remove depends on ISA_DMA_API limitationH Hartley Sweeten
Use the new comedi_isadma module to provide the ISA DMA support. This removes all the ISA_DMA_API code from this driver and allows the driver to be used on platforms that don't support the ISA_DMA_API. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: dt282x: remove depends on ISA_DMA_API limitationH Hartley Sweeten
Use the new comedi_isadma module to provide the ISA DMA support. This removes all the ISA_DMA_API code from this driver and allows the driver to be used on platforms that don't support the ISA_DMA_API. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: das1800: remove depends on ISA_DMA_API limitationH Hartley Sweeten
Use the new comedi_isadma module to provide the ISA DMA support. This removes all the ISA_DMA_API code from this driver and allows the driver to be used on platforms that don't support the ISA_DMA_API. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: das16: remove depends on ISA_DMA_API limitationH Hartley Sweeten
Use the new comedi_isadma module to provide the ISA DMA support. This removes all the ISA_DMA_API code from this driver and allows the driver to be used on platforms that don't support the ISA_DMA_API. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: pcl812: remove depends on ISA_DMA_API limitationH Hartley Sweeten
Use the new comedi_isadma module to provide the ISA DMA support. This removes all the ISA_DMA_API code from this driver and allows the driver to be used on platforms that don't support the ISA_DMA_API. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: pcl816: remove depends on ISA_DMA_API limitationH Hartley Sweeten
Use the new comedi_isadma module to provide the ISA DMA support. This removes all the ISA_DMA_API code from this driver and allows the driver to be used on platforms that don't support the ISA_DMA_API. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: pcl818: remove depends on ISA_DMA_API limitationH Hartley Sweeten
Use the new comedi_isadma module to provide the ISA DMA support. This removes all the ISA_DMA_API code from this driver and allows the driver to be used on platforms that don't support the ISA_DMA_API. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: comedi_isadma: introduce helper module for ISA DMAH Hartley Sweeten
Introduce a new helper module to consolidate all the ISA DMA code. This will allow removing the "depends on ISA_DMA_API" from the legacy drivers that can use DMA for async command support. This module is complete based on the various uses of ISA DMA in the comedi drivers. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: das1800: tidy up das1800_ai_transfer_size()H Hartley Sweeten
For aesthetics, pass the fill time 'ns' as a parameter to this function. Refactor this function to calculate the transfer size in 'samples' instead of 'bytes'. This removes the need to constantly multiply the values by the 'sample_size'. It also helps avoid any possible integer overflow issues. Use the comedi_nsamples_left() helper to limit the samples when cmd->stop_src is TRIG_COUNT. Use comedi_samples_to_bytes() to return the final DMA size in bytes. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: das1800: remove hard coded 'sample_size'H Hartley Sweeten
Use the comedi_bytes_per_sample() helper to remove the hard coded sample_size in suggest_transfer_size(). The helper function needs to comedi_subdevice pointer. Change the parameters passed to suggest_transfer_size() and setup_dma() so that this pointer is available. Rename these functions so they have namespace associated with the driver. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: ni_labpc_isadma: introduce labpc_isadma_program()H Hartley Sweeten
Introduce a helper function to program the ISA DMA controller. Program the ISA DMA as described in Documentation/DMA-ISA-LPC.txt. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: ni_labpc_isadma: move dma programming out of labpc_drain_dma()H Hartley Sweeten
The external caller of labpc_drain_dma() does not enable the DMA transfer. Only the call from handle_isa_dma() results in the programmed DMA operation getting enabled. For aesthetics, move the dma programming to handle_isa_dma(). Make sure the DMA operation would actually do something (dma->size != 0) before programming it to avoid enabling the DMA at the end of a stop_src == TRIG_COUNT command. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: ni_labpc_isadma: tidy up labpc_drain_dma()H Hartley Sweeten
Tidy up the code that determines the number of samples to read for the current DMA transfer and how many samples are needed for the next DMA, Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: ni_labpc_isadma: introduce labpc_isadma_disable()H Hartley Sweeten
Introduce a helper function to disable and the ISA DMA controller and return the residue as described in Documentation/DMA-ISA-LPC.txt. The DMA will always be disabled when labpc_setup_dma() is called. Remove the unnecessary disable in that function. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: ni_labpc_isadma: convert 'dma_buffer_size' to a defineH Hartley Sweeten
For aesthetics, convert this statis const global variable to a define. Cleanup the maximum 'size' calc in labpc_suggest_transfer_size(). The modulo operation will always result in '0'. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: ni_labpc_isadma: remove hard coded samples sizeH Hartley Sweeten
Use the comedi_bytes_per_sample() helper and remove the hard coded sample size. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: ni_at_a2150: introduce a2150_isadma_disable()H Hartley Sweeten
Introduce a helper function to disable and the ISA DMA controller and return the residue as described in Documentation/DMA-ISA-LPC.txt. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: ni_at_a2150: introduce a2150_isadma_program()H Hartley Sweeten
Introduce a helper function to program the ISA DMA controller. Program the ISA DMA as described in Documentation/DMA-ISA-LPC.txt. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: pcl812: introduce pcl812_isadma_disable()H Hartley Sweeten
According to Documentation/DMA-ISA-LPC.txt, the DMA lock needs to be claimed before using any of the ISA DMA routines. Introduce a helper function to disable the ISA DMA controller and add the necessary locking calls. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: pcl812: introduce pcl812_isadma_program()H Hartley Sweeten
Introduce a helper function to program the ISA DMA controller. Program the ISA DMA as described in Documentation/DMA-ISA-LPC.txt. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: das16: introduce das16_isadma_disable()H Hartley Sweeten
Introduce a helper function to disable and the ISA DMA controller and return the residue as described in Documentation/DMA-ISA-LPC.txt. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: das16: introduce das16_isadma_program()H Hartley Sweeten
Introduce a helper function to program the ISA DMA controller. Program the ISA DMA as described in Documentation/DMA-ISA-LPC.txt. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: das16: move dma transfer 'size' to dma descriptorH Hartley Sweeten
For asethetics, move the variable that holds the dma transfer 'size' into the dma descriptor. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: das1800: introduce das1800_isadma_disable()H Hartley Sweeten
Introduce a helper function to disable and the ISA DMA controller and return the residue as described in Documentation/DMA-ISA-LPC.txt. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: das1800: introduce das1800_isadma_program()H Hartley Sweeten
Introduce a helper function to program the ISA DMA controller. Program the ISA DMA as described in Documentation/DMA-ISA-LPC.txt. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: das1800: move dma transfer 'size' to dma descriptorH Hartley Sweeten
For asethetics, move the variable that holds the dma transfer 'size' into the dma descriptor. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: das1800: pass dma descriptor to das1800_flush_dma_channel()H Hartley Sweeten
Instead of passing the dma descriptor 'chan' and 'virt_addr' just pass the dma descriptor. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: dt282x: introduce dt282x_isadma_disable()H Hartley Sweeten
According to Documentation/DMA-ISA-LPC.txt, the DMA lock needs to be claimed before using any of the ISA DMA routines. Introduce a helper function to disable the ISA DMA controller and add the necessary locking calls. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: dt282x: introduce dt282x_isadma_program()H Hartley Sweeten
Introduce a helper function to program the ISA DMA controller. Program the ISA DMA as described in Documentation/DMA-ISA-LPC.txt. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: pcl816: introduce pcl816_isadma_disable()H Hartley Sweeten
According to Documentation/DMA-ISA-LPC.txt, the DMA lock needs to be claimed before using any of the ISA DMA routines. Introduce a helper function to disable the ISA DMA controller and add the necessary locking calls. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: pcl816: introduce pcl816_isadma_program()H Hartley Sweeten
Introduce a helper function to program the ISA DMA controller. Program the ISA DMA as described in Documentation/DMA-ISA-LPC.txt. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: pcl818: introduce pcl818_isadma_disable()H Hartley Sweeten
According to Documentation/DMA-ISA-LPC.txt, the DMA lock needs to be claimed before using any of the ISA DMA routines. Introduce a helper function to disable the ISA DMA controller and add the necessary locking calls. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: pcl818: introduce pcl818_isadma_program()H Hartley Sweeten
Introduce a helper function to program the ISA DMA controller. Program the ISA DMA as described in Documentation/DMA-ISA-LPC.txt. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: das16: board is not a PCI deviceH Hartley Sweeten
The DAS16 board is an ISA device not a PCI device. For aesthetics, use dma_{alloc,free}_coherent() to allocate and free the DMA buffers instead of the PCI versions. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: das16: introduce das16_free_dma()H Hartley Sweeten
For aesthetics, move the freeing of the DMA channel and the buffers to a helper function. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: das16 introduce das16_alloc_dma()H Hartley Sweeten
DMA is optional with this driver. Introduce a helper function to request the DMA channel and allocate the buffers. Don't fail the driver attach if the user passed an invalid DMA channel or the channel cannot be requested. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: das16: introduce struct das16_dma_descH Hartley Sweeten
For aesthetics, introduce a struct to hold the DMA descriptor data. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: dt282x: remove VIRT_TO_BUS dependancyH Hartley Sweeten
Use dma_{alloc,free}_coherent() to allocate and free the DMA buffers. This removes the dependancy on VIRT_TO_BUS. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: dt282x: introduce struct dt282x_dma_descH Hartley Sweeten
For aesthetics, introduce a struct to hold the DMA descriptor data. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: dt282x: introduce dt282x_alloc_dma()H Hartley Sweeten
The IRA and DMA are optional with this driver but both are required to support async commands. Introduce a helper function to request the IRQ and DMA channel and allocate the buffers. Don't fail the driver attach if the user passed an invalid IRQ or DMA channel or they cannot be requested. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: pcl812: remove VIRT_TO_BUS dependancyH Hartley Sweeten
Use dma_{alloc,free}_coherent() to allocate and free the DMA buffers. This removes the dependancy on VIRT_TO_BUS. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: pcl812: introduce struct pcl812_dma_descH Hartley Sweeten
For aesthetics, introduce a struct to hold the DMA descriptor data. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: pcl812: introduce pcl812_free_dma()H Hartley Sweeten
For aesthetics, move the freeing of the DMA channel and the buffers to a helper function. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: pcl812: introduce pcl812_alloc_dma()H Hartley Sweeten
DMA is optional with this driver. Introduce a helper function to request the DMA channel and allocate the buffers. Don't fail the driver attach if the user passed an invalid DMA channel or the channel cannot be requested. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: pcl816: fix short DMA transactionsH Hartley Sweeten
When the cmd->stop_src == TRIG_COUNT the last DMA transfer might be smaller than the buffer size. This results in invalid data being added to the async buffer. Add a 'size' member to the DMA descriptor and initialize it with the actual size of the DMA transfer. Use that in interrupt and ai subdevice (*poll) function to return the proper number of samples. Use the comedi_bytes_to_samples() helper to convert the byte size to comedi samples in the interrupt handler. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: pcl816: remove VIRT_TO_BUS dependancyH Hartley Sweeten
Use dma_{alloc,free}_coherent() to allocate and free the DMA buffers. This removes the dependancy on VIRT_TO_BUS. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: pcl816: introduce struct pcl816_dma_descH Hartley Sweeten
For aesthetics, introduce a struct to hold the DMA descriptor data. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: pcl816: introduce pcl816_free_dma()H Hartley Sweeten
For aesthetics, move the freeing of the DMA channel and the buffers to a helper function. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: pcl816: introduce pcl816_alloc_dma()H Hartley Sweeten
The IRA and DMA are optional with this driver but both are required to support async commands. Introduce a helper function to request the IRQ and DMA channel and allocate the buffers. Don't fail the driver attach if the user passed an invalid IRQ or DMA channel or they cannot be requested. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-17staging: comedi: pcl818: fix pcl818_handle_dma() for short DMA transactionH Hartley Sweeten
Currently this function always transfers the full DMA buffer to the comedi async buffer. When the cmd->stop_src == TRIG_COUNT the last DMA transfer might be smaller than the buffer size. This results in invalid data being added to the asunc buffer. Add a 'size' member to the DMA descriptor and initialize it with the actual size of the DMA transfer. Use that in pcl818_handle_dma() to return the proper number of samples. Use the comedi_bytes_to_samples() helper to convert the byte size to comedi samples. Remove the unnecessary 'bufptr' local variable. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>