dma.c

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/*
 *	ApOS (Another Project software for s3c2410)
 *	
 *	This program is free software; you can redistribute it and/or modify
 *	it under the terms of the GNU General Public License version 2 as
 *	published by the Free Software Foundation.
 *			
 *						Copyright caiyuqing
 *
 *	this file define the functions of the DMA block
 *  	本文件实现了对DMA模块进行操作的函数
 */
#include "../include/s3c2410/s3c2410.h"
#include "../include/s3c2410/dma.h"
#include "../include/kernel/irq.h"

extern irq_ptr irq_rotunie[32];

/*
 *	DMA global object,any functions of the dma control is base it. 
 *	DMA全局对象，整个系统的DMA操作(初始化，设置等等)都是基于这个对象的
 */
struct dma_ctrl_object dma_ctrl_object;

/*
 *	system can get the status of a dma opteration througth
 *	thease four global variable
 *	四个全局变量，通过他们系统可以知道dma操作是否已经完成
 */
char sys_dma0_done;
char sys_dma1_done;
char sys_dma2_done;
char sys_dma3_done;

/*
 *	irq for chanel0	
 *	0号通道dma中断服务例程
 */
void dma0_irq(struct cpu_registers *regs);

/*
 *	initialize the DMA object
 *	初始化 dma_ctrl_object 对象
 */
void dma_ctrl_obj_init(struct dma_ctrl_object *dco)
{
	//0通道对象初始化
	dco->chanel0.disrc	=&rDISRC0;
	dco->chanel0.disrcc	=&rDISRCC0;
	dco->chanel0.didst	=&rDIDST0;
	dco->chanel0.didstc	=&rDIDSTC0;
	dco->chanel0.dcon	=&rDCON0;
	dco->chanel0.dstat	=&rDSTAT0;
	dco->chanel0.dcsrc	=&rDCSRC0;
	dco->chanel0.dcdst	=&rDCDST0;
	dco->chanel0.dmasktrig	=&rDMASKTRIG0;
	dco->chanel0.tc_opt	=1;

	//1通道对象初始化
	dco->chanel1.disrc	=&rDISRC1;
	dco->chanel1.disrcc	=&rDISRCC1;
	dco->chanel1.didst	=&rDIDST1;
	dco->chanel1.didstc	=&rDIDSTC1;
	dco->chanel1.dcon	=&rDCON1;
	dco->chanel1.dstat	=&rDSTAT1;
	dco->chanel1.dcsrc	=&rDCSRC1;
	dco->chanel1.dcdst	=&rDCDST1;
	dco->chanel1.dmasktrig	=&rDMASKTRIG1;
	dco->chanel1.tc_opt	=1;
	
	//2通道对象初始化
	dco->chanel2.disrc	=&rDISRC2;
	dco->chanel2.disrcc	=&rDISRCC2;
	dco->chanel2.didst	=&rDIDST2;
	dco->chanel2.didstc	=&rDIDSTC2;
	dco->chanel2.dcon	=&rDCON2;
	dco->chanel2.dstat	=&rDSTAT2;
	dco->chanel2.dcsrc	=&rDCSRC2;
	dco->chanel2.dcdst	=&rDCDST2;
	dco->chanel2.dmasktrig	=&rDMASKTRIG2;
	dco->chanel2.tc_opt	=1;
	
	//3通道对象初始化
	dco->chanel3.disrc	=&rDISRC3;
	dco->chanel3.disrcc	=&rDISRCC3;
	dco->chanel3.didst	=&rDIDST3;
	dco->chanel3.didstc	=&rDIDSTC3;
	dco->chanel3.dcon	=&rDCON3;
	dco->chanel3.dstat	=&rDSTAT3;
	dco->chanel3.dcsrc	=&rDCSRC3;
	dco->chanel3.dcdst	=&rDCDST3;
	dco->chanel3.dmasktrig	=&rDMASKTRIG3;
	dco->chanel3.tc_opt	=1;

	irq_rotunie[INT_DMA0]	=&dma0_irq;

}


/*
 *	we use chanel0 to perform the data transfer between memory and memory
 *	本函数使用DMA的0号通道对内存间的数据传送
 *	src_addr:	source address 		源地址
 *	dest_addr:	destination address	目标地址
 *	len:		data length(byts)	数据长度(字节)
 */
int dma_mem_copy(unsigned int* src_addr,unsigned int* dest_addr,int len)
{
	struct dma_ctrl_object *dma_obj	=&dma_ctrl_object;
	struct dma_chanel *dma_chanel	=((struct dma_chanel *)dma_obj)+0;
	
	unsigned int tc=(len);
	
	irq_mask(INT_DMA0,IRQ_UNMASK);
	sys_dma0_done=0;
	
	//必须清除DCache,否则数据会出错
	invalidate_DCache();
	/*
	 *	LOC: 0	address increment
	 *	INC: 0	AHB
	 */
	*dma_chanel->disrc=src_addr;
	*dma_chanel->disrcc=(0<<LOC_OFFSET)|(0<<INC_OFFSET);

	*dma_chanel->didst=dest_addr;
	*dma_chanel->didstc=(0<<LOC_OFFSET)|(0<<INC_OFFSET);
	
	/*
	 *	DMD_HS:	 1	Handshake mode.
	 *
	 *	SYNC:	 1	DREQ and DACK are synchronized to HCLK.
	 *			由于是内存间的数据传递，数据源设备是内存，应该同步于HCLK
	 *			所以将SYNC位设置为1
	 *			若数据源设备是属于外部总线的，则必须同步于PCLK，必须将该
	 *			位设置为0
	 *			
	 *	INT:	 1	interrupt request is generated when all the transfer is done.
	 *			当该位为1时，则DMA完成(既CURR_TC变为0)之后相应的DMA中断将被触发
	 *	
	 *	TSZ:	 0	an union transfer is performed.
	 *			DMA设备每次占用总线时传递数据的次数，0是传递1次后释放总线，
	 *			1是传递4次后再释放总线
	 *			
	 *	SERVMODE:1	Whole service mode.
	 *
	 *	SWHW_SEL:0	S/W request mode.
	 *			DMA触发方式的选择，0软件触发，1为硬件触发。
	 *			当设置为硬件触发之后我们必须设置HWSRCSEL位
	 *			为4个通道配置触发源
	 *			
	 *	RELOAD:	 1	DMA channel (DMA REQ) is turned off when a current value of 
	 *			transfer count becomes 0.
	 *			当设置为1时，则一旦某通道完成了DMA操作(既CURR_TC变为0)，该通道
	 *			将被马上关闭。(既DMASKTRIG寄存器的ON_OFF位被置0)
	 *			若设置为0时，则完成DMA操作之后的通道并不关闭(既DMASKTRIG寄存器
	 *			的ON_OFF位还是1)，它会紧接着处理新的请求(如果有的话)
	 *
	 *	DSZ:	 00	BYTE.
	 *			DMA每次传送数据的字节数
	 *			
	 *	TC:	 tc 当前DMA请求总共需要传递多少次数据(必须占用多少次总线)
	 *		 一个DMA操作传递的数据字节数实际上是 DSZ*TSZ*TC
	 *			
	 */
	*dma_chanel->dcon=(1<<DMD_HS_OFFSET)|(1<<SYNC_OFFSET)|
			(1<<INT_OFFSET)|(0<<TSZ_OFFSET)|(1<<SERVMODE_OFFSET)|
			(0<<SWHW_SEL_OFFSET)|(1<<RELOAD_OFFSET)|(BYTE<<DSZ_OFFSET)|
			(tc);
	//ready?
	//while((*dma_chanel->dstat)&0xfffff!=0);
	while(((*dma_chanel->dstat)>>20)&0x3!=0);//DMA is busy
	/*
	 *	DMA on, SW_TRIG 
	 *	开启DMA通道，触发一个DMA信号
	 */
	*dma_chanel->dmasktrig=(1<<ON_OFF_OFFSET)|(1<<SW_TRIG_OFFSET);
	
	return tc;

}
void dma_stop(int chanel)
{
	struct dma_ctrl_object *dma_obj	=&dma_ctrl_object;
	struct dma_chanel *dma_chanel	=((struct dma_chanel *)dma_obj)+chanel;
	
	*dma_chanel->dmasktrig=(1<<STOP_OFFSET);
}
/*
 *	irq for dam chanel0
 *	dma chanel0 中断服务例程
 */
void dma0_irq(struct cpu_registers *regs)
{
	/*
	 *	clean the interrupt pin and mask the interrupt,set
	 *	the sys_dmaX_done to 1,indecate that the DMA opteration 
	 *	is complete.
	 *	
	 *	清除中断信号并屏蔽该中断,将sys_dmaX_done
	 *	设置为0表示一个DMA操作已经完成
	 */
	clean_src_pnd(INT_DMA0);
	clean_int_pnd(INT_DMA0);
	irq_mask(INT_DMA0,IRQ_MASK);
	sys_dma0_done=1;
}

int dma_copy_done()
{
	return sys_dma0_done;
}