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Commit 6a64877f authored by Ian Abbott's avatar Ian Abbott Committed by Greg Kroah-Hartman
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staging: comedi: plx9080.h: Add kerneldoc comments 



Document the DMA descriptor `struct plx_dma_desc`, and the DMA abort
function `plx9080_abort_dma()`.

Signed-off-by: default avatarIan Abbott <abbotti@mev.co.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 457bec0f

drivers/staging/comedi/drivers/plx9080.h

+29 −6
Original line number Diff line number Diff line
@@ -19,16 +19,27 @@ 
#ifndef __COMEDI_PLX9080_H

#define __COMEDI_PLX9080_H



/* descriptor block used for chained dma transfers */

/**

 * struct plx_dma_desc - DMA descriptor format for PLX PCI 9080

 * @pci_start_addr:	PCI Bus address for transfer (DMAPADR).

 * @local_start_addr:	Local Bus address for transfer (DMALADR).

 * @transfer_size:	Transfer size in bytes (max 8 MiB) (DMASIZ).

 * @next:		Address of next descriptor + flags (DMADPR).

 *

 * Describes the format of a scatter-gather DMA descriptor for the PLX

 * PCI 9080.  All members are raw, little-endian register values that

 * will be transferred by the DMA engine from local or PCI memory into

 * corresponding registers for the DMA channel.

 *

 * The DMA descriptors must be aligned on a 16-byte boundary.  Bits 3:0

 * of @next contain flags describing the address space of the next

 * descriptor (local or PCI), an "end of chain" marker, an "interrupt on

 * terminal count" bit, and a data transfer direction.

 */

struct plx_dma_desc {

	__le32 pci_start_addr;

	__le32 local_start_addr;

	/* transfer_size is in bytes, only first 23 bits of register are used */

	__le32 transfer_size;

	/*

	 * address of next descriptor (quad word aligned), plus some

	 * additional bits (see PLX_REG_DMADPR)

	 */

	__le32 next;

};
@@ -594,6 +605,18 @@ struct plx_dma_desc { 


#define PLX_PREFETCH   32



/**

 * plx9080_abort_dma - Abort a PLX PCI 9080 DMA transfer

 * @iobase:	Remapped base address of configuration registers.

 * @channel:	DMA channel number (0 or 1).

 *

 * Aborts the DMA transfer on the channel, which must have been enabled

 * and started beforehand.

 *

 * Return:

 *	%0 on success.

 *	-%ETIMEDOUT if timed out waiting for abort to complete.

 */

static inline int plx9080_abort_dma(void __iomem *iobase, unsigned int channel)

{

	void __iomem *dma_cs_addr;