Hi all
We have a requirement of running a periodic timer for
5 millisecond using RISC timers in CPM module of
MPC8260. The OS is monta vista linux and target is
MPC8260 I have written a sample code to start a
periodic timer using MPC8260.
But it hangs when SET TIMER command is issued to the
CPCR register. The cross compiler we r using is
ppc_82xx-gcc.
Can anyone pls help me in getting this right ?
I am pasting the code here
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/*Start of code snippet ignoring the header files */
cpm8xx_t *cpmp;
volatile immap_t *immap = (immap_t *)IMAP_ADDR;
#define CPCR_OPCODE ( 8 << 8 ) /* CPCR Opcode Field:
SET TIMER */
#define CPCR_CHNUM ( 5 << 4 ) /* CPCR Ch Num Field:
SPI/IDMA2/RISC Timers */
#define CPCR_FLAG ( 1 << 0 ) /* CPCR Flag Field:
Process Command */
#define PROFF_RISCTT ((uint)0x01B0)
void risc_timer_handler(int irq, void *dev_id, struct
pt_regs *regs)
{
unsigned int i, rter;
printk("Inside risc timer handler \n");
/*read RTER to see which timers have caused
interrupts.
*/
rter = immap->im_cpm.cp_rter ;
/*The RISC timer event bits are usually cleared
*by this time
*/
immap->im_cpm.cp_rter = 0xffff ;
}
int __init device_init(void)
{
unsigned int ticks = 0;
unsigned int interval = 1000;
unsigned short prescaler = 0;
volatile cpm8xx_t *cp;
/*
* Write the TIMEP bits of the RCCR with 111111 to
generate the slowest
* clock, This value generates a tick every 65,536
clocks, which is every
* 2.6 milliseconds at 25 MHz.
*/
immap->im_cpm.cp_rccr = ( 0x3f << 8 );
/*
* Configure the TM_BASE in the RISC timer table
parameter RAM to point to a location in the
* dual-port RAM with 4 bytes available.
*/
// rt_pram_t *rtt_pramp = (rt_pram_t
*)(&cpmp->cp_dparam[PROFF_RISCTT]);
cp = (cpm8xx_t *)&(immap->im_cpm);
rt_pram_t *rtt_pramp = (rt_pram_t *)&cp->cp_dparam;
/*
* Assuming the beginning of dual-port RAM is
available,
* write 0x0000 to TM_BASE.
*/
rtt_pramp->tm_base = 0x0000;
// rtt_pramp->tm_base = m8xx_cpm_dpalloc(16);
logic 1
/*Write 0x0000 to the TM_CNT field in the RISC
timer table
*parameter RAM to see how many ticks elapsed since
the RISC
*internal timer was enabled.
*/
rtt_pramp->tm_cnt = 0x0;
/*Write 0xFFFF to the RTER to clear any previous
events.
*/
immap->im_cpm.cp_rter = 0xffff;
/* Write 0x0001 to the RTMR to enable RISC timer 0
* and timer 1 to generate an interrupt.
*/
immap->im_cpm.cp_rtmr |= 0x1 ;
if(
request_irq(SIU_INT_RISC,risc_timer_handler,0,0,0) <
0)
{
printk("\n unable to register the RISC timer
\n");
}
/*Write 0xC000_080D to the TM_CMD field of the RISC
timer table
parameter RAM. This enables RISC timer 0 to
timeout after 2,061(decimal)
ticks of the timer. The timer automatically
restarts after it times out.
*/
rtt_pramp->tm_cmd = 0xC000080D ;
/* Enter Command: SET TIMER */
while (immap->im_cpm.cp_cpcr & CPM_CR_FLG);
immap->im_cpm.cp_cpcr =
mk_cr_cmd(CPM_CR_CH_SPI, CPM_CR_SET_TIMER) |
CPM_CR_FLG;
while (immap->im_cpm.cp_cpcr & CPM_CR_FLG);
/* Set RCCR[TIME] to enable the RISC timer to
* begin operation.
*/
immap->im_cpm.cp_rccr = ( 1 << 15 );
return 0;
}
void cleanup_device(void)
{
request_irq(SIU_INT_RISC, NULL, 0, 0,
0);
printk(KERN_INFO "cleaned up \n");
}
module_init(device_init);
module_exit(cleanup_device);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("");
MODULE_DESCRIPTION("driver code");
EXPORT_NO_SYMBOLS;
/*End of code snippet */
-------------------------------------------------------
Thanks in Advance
Jagan
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