jtag.c

用于TM1300/PNX1300系列DSP（主要用于视频处理）的jtag接口程序

#include <tm1/mmio.h>

/* macros */
#define MAGIC_NUMBER 		0x12345678
#define SWAPPED_MAGIC 		0x78563412
#define GOOD_BYE   			0x00dead00
#define SWAPPED_BYE 		0x00adde00
#define OFULL				0x1
#define IFULL   			0x2
#define SLEEPLESS 			0x4
#define JTAG_INTERRUPT_NO 	18


void waitForIFullBit()
{
	int bit = 0;
	do {
		
        bit = MMIO(JTAG_CTL);

	/* Keep waiting until Ifull bit is set by the host side        */
	} while((bit & IFULL) == 0);
} 

int main()
{

int data;
static int flag = 0;

MMIO(JTAG_DATA_IN)  = 0;

while (1) {

	if (flag == 0 ) {

		flag = 1;

		/* Send out the magic number to host side progam            */
		MMIO(JTAG_DATA_OUT) = MAGIC_NUMBER;
	}
    else  {
		flag = 0;

		/* Send out the swapped magic number to host side progam    */
		MMIO(JTAG_DATA_OUT) = SWAPPED_MAGIC;

    }

    /* Set the Ofull Bit after writing to JTAG_DATA_OUT register     */
    /* This signals the host side that valid/readable data exists in */
    /* MMIO(JTAG_DATA_OUT) register. Setting sleepless bit is always */
    /* good.                                                         */
	MMIO(JTAG_CTL)	    = (OFULL | SLEEPLESS);

    /* wait for host to send data into JTAG_DATA_IN register         */
    /* This is signalled by host setting the MMIO(JTAG_CTL).IFullBit */
	waitForIFullBit();
	data = MMIO(JTAG_DATA_IN);

    /* Clear the IFull bit after reading from JTAG_DATA_IN           */
	MMIO(JTAG_CTL) = SLEEPLESS; 

	if ( data == SWAPPED_MAGIC || data == MAGIC_NUMBER ) {

	    /* setting IFull bit results in a Pending JTAG interrupt     */
	    /* so clear the interrupt just for good programming's sake   */
		MMIO(ICLEAR) = (1 << JTAG_INTERRUPT_NO);
		continue;
	}
	else if (data == GOOD_BYE || data == SWAPPED_BYE)
		break;
	else {
		MMIO(ICLEAR) = (1 << JTAG_INTERRUPT_NO);
		return -1;
	}
}

/*          Doesn't matter but still clear the interrupt            */
MMIO(ICLEAR) = (1 << JTAG_INTERRUPT_NO);
return 0;

}