Hi,
We able to integrate u-boot with Linux along with Watchdog enabled for
PPC440gx processor.
Here I am giving the modification we did to make it work.
The intention to write this mail is to provide a reference code for the
people who wants to use Watchdog feature with PPC440gx.
We have used u-boot-1.1.4 and Linux Kernel of version 2.6.16 on PPC440gx
processor.
Steps that we have taken:
1. Enabled 'CONFIG_WATCHDOG' flag code in u-boot code.
2. Modified the
'kernel-2.6.16.1-ts.amcc440gx.basic.1\arch\ppc\kernel\time.c' (Modified
code starts with 'Sachin' tag)
void reset_watchdog(void)
{
/* Sachin: Resetting Bit#0 and Bit#1
mtspr(SPRN_TSR, 0xc0000000);
/*Sachin: added - end */
}
void timer_interrupt(struct pt_regs * regs)
{
int next_dec;
unsigned long cpu = smp_processor_id();
unsigned jiffy_stamp = last_jiffy_stamp(cpu);
extern void do_IRQ(struct pt_regs *);
/* Sachin: Reset the Watchdog timer */
reset_watchdog();
/*Sachin: added - end */
:
:
:
:
if (ppc_md.heartbeat &&
!ppc_md.heartbeat_count--)
ppc_md.heartbeat();
irq_exit();
}
3. Modified the
'kernel-2.6.16.1-ts.amcc440gx.basic.1\arch\ppc\syslib\ibm44x_common.c':
void __init ibm44x_calibrate_decr(unsigned int freq)
{
unsigned long value;
tb_ticks_per_jiffy = freq / HZ;
tb_to_us = mulhwu_scale_factor(freq, 1000000);
:
:
:
/*Sachin: added - start */
value = mfspr(SPRN_TCR);
value |= TCR_DIE;
mtspr(SPRN_TCR, value);
/*Sachin: added - end */
//mtspr(SPRN_TCR, TCR_DIE);
}
Thanks.
Regards,
Sachin Rane
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