| Message ID | 20221228191125.37584-2-samuel@sholland.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [1/2] lib: utils: Add fdt_add_cpu_idle_states() helper function | expand |
On Thu, Dec 29, 2022 at 12:41 AM Samuel Holland <samuel@sholland.org> wrote: > > Add D1's nonretentive suspend state to the devicetree so S-mode software > knows about it and can use it. > > Latency and power measurements were taken on an Allwinner Nezha board: > - Entry latency was measured from the beginning of sbi_ecall_handler() > to before the call to wfi() in sun20i_d1_hart_suspend(). > - Exit latency was measured from the beginning of sbi_init() to before > the call to sbi_hart_switch_mode() in init_warmboot(). > - There was a 17.5 mW benefit from non-retentive suspend compared to > WFI, with a 170 mW cost during the 107 us entry/exit period. This > provides a break-even point around 1040 us. Residency includes entry > latency, so round this up to 1100 us. > - The hardware power sequence latency (after the WFI) is assumed to be > negligible, so set the wakeup latency to the exit latency. > > Signed-off-by: Samuel Holland <samuel@sholland.org> Looks good to me. Reviewed-by: Anup Patel <anup@brainfault.org> Regards, Anup > --- > > platform/generic/allwinner/sun20i-d1.c | 20 ++++++++++++++++++++ > 1 file changed, 20 insertions(+) > > diff --git a/platform/generic/allwinner/sun20i-d1.c b/platform/generic/allwinner/sun20i-d1.c > index 1da9e5b..8ca556e 100644 > --- a/platform/generic/allwinner/sun20i-d1.c > +++ b/platform/generic/allwinner/sun20i-d1.c > @@ -12,6 +12,7 @@ > #include <sbi/sbi_error.h> > #include <sbi/sbi_hsm.h> > #include <sbi/sbi_pmu.h> > +#include <sbi_utils/fdt/fdt_fixup.h> > #include <sbi_utils/fdt/fdt_helper.h> > #include <sbi_utils/irqchip/fdt_irqchip_plic.h> > > @@ -202,6 +203,24 @@ static int sun20i_d1_final_init(bool cold_boot, const struct fdt_match *match) > return 0; > } > > +static const struct sbi_cpu_idle_state sun20i_d1_cpu_idle_states[] = { > + { > + .name = "cpu-nonretentive", > + .suspend_param = SBI_HSM_SUSPEND_NON_RET_DEFAULT, > + .local_timer_stop = true, > + .entry_latency_us = 40, > + .exit_latency_us = 67, > + .min_residency_us = 1100, > + .wakeup_latency_us = 67, > + }, > + { } > +}; > + > +static int sun20i_d1_fdt_fixup(void *fdt, const struct fdt_match *match) > +{ > + return fdt_add_cpu_idle_states(fdt, sun20i_d1_cpu_idle_states); > +} > + > static void thead_c9xx_pmu_ctr_enable_irq(uint32_t ctr_idx) > { > unsigned long mip_val; > @@ -265,5 +284,6 @@ static const struct fdt_match sun20i_d1_match[] = { > const struct platform_override sun20i_d1 = { > .match_table = sun20i_d1_match, > .final_init = sun20i_d1_final_init, > + .fdt_fixup = sun20i_d1_fdt_fixup, > .extensions_init = sun20i_d1_extensions_init, > }; > -- > 2.37.4 > > > -- > opensbi mailing list > opensbi@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/opensbi
diff --git a/platform/generic/allwinner/sun20i-d1.c b/platform/generic/allwinner/sun20i-d1.c index 1da9e5b..8ca556e 100644 --- a/platform/generic/allwinner/sun20i-d1.c +++ b/platform/generic/allwinner/sun20i-d1.c @@ -12,6 +12,7 @@ #include <sbi/sbi_error.h> #include <sbi/sbi_hsm.h> #include <sbi/sbi_pmu.h> +#include <sbi_utils/fdt/fdt_fixup.h> #include <sbi_utils/fdt/fdt_helper.h> #include <sbi_utils/irqchip/fdt_irqchip_plic.h> @@ -202,6 +203,24 @@ static int sun20i_d1_final_init(bool cold_boot, const struct fdt_match *match) return 0; } +static const struct sbi_cpu_idle_state sun20i_d1_cpu_idle_states[] = { + { + .name = "cpu-nonretentive", + .suspend_param = SBI_HSM_SUSPEND_NON_RET_DEFAULT, + .local_timer_stop = true, + .entry_latency_us = 40, + .exit_latency_us = 67, + .min_residency_us = 1100, + .wakeup_latency_us = 67, + }, + { } +}; + +static int sun20i_d1_fdt_fixup(void *fdt, const struct fdt_match *match) +{ + return fdt_add_cpu_idle_states(fdt, sun20i_d1_cpu_idle_states); +} + static void thead_c9xx_pmu_ctr_enable_irq(uint32_t ctr_idx) { unsigned long mip_val; @@ -265,5 +284,6 @@ static const struct fdt_match sun20i_d1_match[] = { const struct platform_override sun20i_d1 = { .match_table = sun20i_d1_match, .final_init = sun20i_d1_final_init, + .fdt_fixup = sun20i_d1_fdt_fixup, .extensions_init = sun20i_d1_extensions_init, };
Add D1's nonretentive suspend state to the devicetree so S-mode software knows about it and can use it. Latency and power measurements were taken on an Allwinner Nezha board: - Entry latency was measured from the beginning of sbi_ecall_handler() to before the call to wfi() in sun20i_d1_hart_suspend(). - Exit latency was measured from the beginning of sbi_init() to before the call to sbi_hart_switch_mode() in init_warmboot(). - There was a 17.5 mW benefit from non-retentive suspend compared to WFI, with a 170 mW cost during the 107 us entry/exit period. This provides a break-even point around 1040 us. Residency includes entry latency, so round this up to 1100 us. - The hardware power sequence latency (after the WFI) is assumed to be negligible, so set the wakeup latency to the exit latency. Signed-off-by: Samuel Holland <samuel@sholland.org> --- platform/generic/allwinner/sun20i-d1.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+)