| /* SPDX-License-Identifier: GPL-2.0 */ | 
 | #ifndef __ASM_GENERIC_DMA_H | 
 | #define __ASM_GENERIC_DMA_H | 
 | /* | 
 |  * This file traditionally describes the i8237 PC style DMA controller. | 
 |  * Most architectures don't have these any more and can get the minimal | 
 |  * implementation from kernel/dma.c by not defining MAX_DMA_CHANNELS. | 
 |  * | 
 |  * Some code relies on seeing MAX_DMA_ADDRESS though. | 
 |  */ | 
 | #define MAX_DMA_ADDRESS PAGE_OFFSET | 
 |  | 
 | extern int request_dma(unsigned int dmanr, const char *device_id); | 
 | extern void free_dma(unsigned int dmanr); | 
 |  | 
 | #endif /* __ASM_GENERIC_DMA_H */ |