[Pdbg] [PATCH v2 3/7] libpdbg/p8chip.c: Only write the SP_STOP bit once

[Alistair Popple]

The POWER8 EKB does do retries for ramming which is where this code came from, 
however retries are not done for all cases of SP_STOP in the EKB so following 
the workbook is probably best.

- Alistair

On Tuesday, 12 March 2019 11:49:16 AM AEDT Nicholas Piggin wrote:
> The workbook recipe is to write SP_STOP once, then poll for status.
> 
> Also add a small delay between polling to give a reasonable timeout
> and avoid hitting the scom bus hard for no good reason.
> 
> Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
> ---
>  libpdbg/p8chip.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/libpdbg/p8chip.c b/libpdbg/p8chip.c
> index 61b1e25..b93e953 100644
> --- a/libpdbg/p8chip.c
> +++ b/libpdbg/p8chip.c
> @@ -286,9 +286,11 @@ static int p8_thread_stop(struct thread *thread)
>  	struct core *chip = target_to_core(
>  		pdbg_target_require_parent("core", &thread->target));
> 
> +	/* Quiese active thread */
> +	CHECK_ERR(pib_write(&thread->target, DIRECT_CONTROLS_REG,
> DIRECT_CONTROL_SP_STOP)); +
>  	do {
> -		/* Quiese active thread */
> -		CHECK_ERR(pib_write(&thread->target, DIRECT_CONTROLS_REG,
> DIRECT_CONTROL_SP_STOP)); +		usleep(1);
> 
>  		/* Wait for thread to quiese */
>  		CHECK_ERR(pib_read(&thread->target, RAS_STATUS_REG, &val));