Function report

Linux Kernel

v5.5.9

Brick Technologies Co., Ltd

Source Code:kernel\dma.c Create Date:2022-07-28 10:55:29
Last Modify:2020-03-12 14:18:49 Copyright©Brick
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Annotation kernel can get tool activityDownload SCCTChinese

Name:_dma - free a reserved system DMA channel*@dmanr: DMA channel number

Proto:void free_dma(unsigned int dmanr)

Type:void

Parameter:

TypeParameterName
unsigned intdmanr
90  If dmanr >= NOTES about DMA transfers:* controller 1: channels 0-3, byte operations, ports 00-1F* controller 2: channels 4-7, word operations, ports C0-DF* - ALL registers are 8 bits only, regardless of transfer size* - channel 4 is not used - cascades 1 into 2 Then
91  printk - print a kernel message*@fmt: format string* This is printk(). It can be called from any context. We want it to work.* We try to grab the console_lock. If we succeed, it's easy - we log the* output and call the console drivers
92  Return
95  If xchg( & lock, 0) == 0 Then
96  printk - print a kernel message*@fmt: format string* This is printk(). It can be called from any context. We want it to work.* We try to grab the console_lock. If we succeed, it's easy - we log the* output and call the console drivers
97  Return