[Question] PowerPC Timer Interrupt

[Hyun]

Hello!

Nowadays I try to use PowerPC in Linux. I am porting some codes which
were implemented for ARM core.

In this code, it can set timer interrupt with micro time unit. In
order to this, it uses OSCR, OSMR1, OIER registers, which exists in
pxa270 Processor (ARM core)

Actually, I want to implement this function on PowerPC, but I think
PowerPC doesn't provide registers for configuring timer interrupt.

The board which I use is GE Faunc VG5, and its mircoprocessor is
PowerPC MPC7455.
I read MPC7455 Manual, but I cannot find the register related to timer
interrupt. There is only timer count clock register. (TBU and TBL)

So, what is the method of implementing timer interrupt in PowerPC?
If I want to make an interrupt after 200us, how can I implement it in
Linux on PowerPC?

Please, if there are any one who knows well, let me know the method!

Have a good day!

[Blunderbuss]

Post by Hyun
Actually, I want to implement this function on PowerPC, but I think
PowerPC doesn't provide registers for configuring timer interrupt.
The board which I use is GE Faunc VG5, and its mircoprocessor is
PowerPC MPC7455.
I read MPC7455 Manual, but I cannot find the register related to timer
interrupt. There is only timer count clock register. (TBU and TBL)

The decrementer register is called DEC.

according to the docs, you can load it with mtspr 22

[Hyun]

Post by Blunderbuss
The decrementer register is called DEC.
according to the docs, you can load it with mtspr 22

Dear Blunderbuss,

Thank you for your reply.
I read the manual about DEC, and then I knew DEC is decrementer
register which can make exception.

But I don't know how to use it exactly.

If I want to make interrupt after 20 usec, May I just put the value of
(20 * tb_ticks_per_usec) into DEC and set MSR[EE] = 1?
(In linux/arch/powerpc/kernel/time.c, 100 ticks per usec)

Would you please tell me what the method to configure timer interrupt
with DEC is?

[rvijay435]

Hi Hyun,
Is your issue resolved or still open ??????
Please let me know the status ASAP.


rvijay435
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http://compgroups.net/comp.os.linux.powerpc/-question-powerpc-timer-interrupt/208266