Kalle Jokiniemi <kalle.jokiniemi@xxxxxxxxx> writes:
> According to measurements, reading the previous state of PER
> domain after wfi takes ~11us on OPP2.
>
> Removed this unneccessary latency from cases where we know
> PER power domain did not try to enter off mode.
>
> Signed-off-by: Kalle Jokiniemi <kalle.jokiniemi@xxxxxxxxx>
Looks good, pulling into PM branch.
But still amazed at such a *huge* latency to read that register.
Kevin
> ---
> arch/arm/mach-omap2/pm34xx.c | 19 +++++++++++++------
> 1 files changed, 13 insertions(+), 6 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c
> index 237c819..b70ea19 100644
> --- a/arch/arm/mach-omap2/pm34xx.c
> +++ b/arch/arm/mach-omap2/pm34xx.c
> @@ -489,12 +489,19 @@ void omap_sram_idle(void)
>
> /* PER */
> if (per_next_state < PWRDM_POWER_ON) {
> - per_prev_state = pwrdm_read_prev_pwrst(per_pwrdm);
> - if (per_prev_state == PWRDM_POWER_OFF) {
> - omap3_per_restore_context();
> - omap3_gpio_restore_pad_context(0);
> - } else if (per_next_state == PWRDM_POWER_OFF)
> - omap3_gpio_restore_pad_context(1);
> + if (per_next_state == PWRDM_POWER_OFF) {
> + /*
> + * Reading the prev-state takes long time (11us@OPP2),
> + * only do it, if we really tried to put PER in OFF
> + */
> + per_prev_state = pwrdm_read_prev_pwrst(per_pwrdm);
> + if (per_prev_state == PWRDM_POWER_OFF) {
> + omap3_per_restore_context();
> + omap3_gpio_restore_pad_context(0);
> + } else if (per_next_state == PWRDM_POWER_OFF) {
> + omap3_gpio_restore_pad_context(1);
> + }
> + }
> omap2_gpio_resume_after_idle();
> omap_uart_resume_idle(2);
> if (per_state_modified)
> --
> 1.5.4.3
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