Jean Pihet <jean.pihet@xxxxxxxxxxxxxx> writes:
> When a wake-up constraint is requested or removed the omap device layer
> dispatches the updated strongest constraint value.
> The power domains get the next power state programmed directly in the
> registers via pwrdm_wakeuplat_update_pwrst.
>
> Note about PM QOS: the MPU and CORE power domains get the next power
> state via cpuidle, which get the strongest wake-up latency constraint
> by querying PM QOS. The usage of PM QOS is temporary, until a generic
> solution is in place.
>
> Tested on OMAP3 Beagleboard in RET/OFF using wake-up latency constraints
> on MPU, CORE and PER.
>
> Signed-off-by: Jean Pihet <j-pihet@xxxxxx>
Subject prefix should be: OMAP2+: powerdomain: ...
> ---
> arch/arm/mach-omap2/powerdomain.c | 100 +++++++++++++++++++++++++++++++++++++
> arch/arm/mach-omap2/powerdomain.h | 24 ++++++++-
> 2 files changed, 122 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/powerdomain.c b/arch/arm/mach-omap2/powerdomain.c
> index eaed0df..54ac955 100644
> --- a/arch/arm/mach-omap2/powerdomain.c
> +++ b/arch/arm/mach-omap2/powerdomain.c
> @@ -19,6 +19,7 @@
> #include <linux/list.h>
> #include <linux/errno.h>
> #include <linux/string.h>
> +
> #include "cm2xxx_3xxx.h"
> #include "prcm44xx.h"
> #include "cm44xx.h"
> @@ -176,6 +177,105 @@ static int _pwrdm_post_transition_cb(struct powerdomain *pwrdm, void *unused)
> return 0;
> }
>
> +/*
> + * Test if the current powerdomain is MPU or CORE
> + *
> + * This function is only used by pwrdm_wakeuplat_update_pwrst
> + * which applies the MPU and CORE power domains constraints using PM QOS.
> + *
> + * This will disappear when all power domains will be controlled directly
> + * from the wake-up latency constraints framework
> + */
> +static inline int is_pwrdm_mpu_or_core(struct powerdomain *pwrdm)
> +{
> + if ((pwrdm == pwrdm_lookup("mpu_pwrdm")) ||
> + (pwrdm == pwrdm_lookup("core_pwrdm")))
> + return 1;
> + else
> + return 0;
> +}
I think Paul pointed this out in the earlier review, but instead of
doing this using string compare each time, set a flag in the powerdomain
at init time can be checked here with a simple check.
> +/**
> + * pwrdm_wakeuplat_update_pwrst - Update power domain power state if needed
> + * @pwrdm: struct powerdomain * to which requesting device belongs to.
> + * @min_latency: the allowed wake-up latency for the given power domain. A
> + * value of 0 means 'no constraint' on the pwrdm.
> + *
> + * Finds the power domain next power state that fulfills the constraint.
> + * Programs a new target state if it is different from current power state.
> + *
> + * Returns 0 upon success.
> + */
> +int pwrdm_wakeuplat_update_pwrst(struct powerdomain *pwrdm, long min_latency)
> +{
> + int ret = 0, new_state = 0;
> +
> + if (!pwrdm) {
> + WARN(1, "powerdomain: %s: invalid parameter(s)", __func__);
> + return -EINVAL;
> + }
> +
> + /*
> + * Apply constraints to MPU and CORE via the PM QOS API.
> + * Every power domain struct has a pm_qos_request_list field
> + */
> + if (is_pwrdm_mpu_or_core(pwrdm)) {
> + if (pm_qos_request_active(&(pwrdm->pm_qos_request)))
> + pm_qos_remove_request(&(pwrdm->pm_qos_request));
> +
> + if (min_latency > 0)
> + pm_qos_add_request(&(pwrdm->pm_qos_request),
> + PM_QOS_CPU_DMA_LATENCY,
> + min_latency);
> +
> + return 0;
> + }
> +
> + /*
> + * Apply constraints to pwrdm other than MPU and CORE by programming
> + * the pwrdm next power state.
> + */
> +
> + /* Find power state with wakeup latency < minimum constraint */
> + for (new_state = 0x0; new_state < PWRDM_MAX_PWRSTS; new_state++) {
> + if (min_latency == 0 ||
> + pwrdm->wakeup_lat[new_state] <= min_latency)
> + break;
> + }
> +
> + switch (new_state) {
> + case PWRDM_FUNC_PWRST_OFF:
> + new_state = PWRDM_POWER_OFF;
> + break;
> + case PWRDM_FUNC_PWRST_OSWR:
> + pwrdm_set_logic_retst(pwrdm, PWRDM_POWER_OFF);
> + new_state = PWRDM_POWER_RET;
> + break;
> + case PWRDM_FUNC_PWRST_CSWR:
> + pwrdm_set_logic_retst(pwrdm, PWRDM_POWER_RET);
> + new_state = PWRDM_POWER_RET;
> + break;
> + case PWRDM_FUNC_PWRST_ON:
> + new_state = PWRDM_POWER_ON;
> + break;
> + default:
> + pr_warn("powerdomain: requested latency constraint not "
> + "supported %s set to ON state\n", pwrdm->name);
> + new_state = PWRDM_POWER_ON;
> + break;
> + }
> +
> + if (pwrdm_read_pwrst(pwrdm) != new_state)
> + ret = omap_set_pwrdm_state(pwrdm, new_state);
> +
> + pr_debug("powerdomain: %s pwrst: curr=%d, prev=%d next=%d "
> + "min_latency=%ld, set_state=%d\n", pwrdm->name,
> + pwrdm_read_pwrst(pwrdm), pwrdm_read_prev_pwrst(pwrdm),
> + pwrdm_read_next_pwrst(pwrdm), min_latency, new_state);
> +
> + return ret;
> +}
> +
> /* Public functions */
>
> /**
> diff --git a/arch/arm/mach-omap2/powerdomain.h b/arch/arm/mach-omap2/powerdomain.h
> index 0b7a357..23b3408 100644
> --- a/arch/arm/mach-omap2/powerdomain.h
> +++ b/arch/arm/mach-omap2/powerdomain.h
> @@ -19,7 +19,10 @@
>
> #include <linux/types.h>
> #include <linux/list.h>
> -
> +#include <linux/plist.h>
> +#include <linux/mutex.h>
> +#include <linux/spinlock.h>
> +#include <linux/pm_qos_params.h>
> #include <linux/atomic.h>
>
> #include <plat/cpu.h>
> @@ -46,6 +49,15 @@
>
> #define PWRSTS_OFF_RET_ON (PWRSTS_OFF_RET | (1 << PWRDM_POWER_ON))
>
> +/* Powerdomain functional power states */
> +#define PWRDM_FUNC_PWRST_OFF 0x0
> +#define PWRDM_FUNC_PWRST_OSWR 0x1
> +#define PWRDM_FUNC_PWRST_CSWR 0x2
> +#define PWRDM_FUNC_PWRST_ON 0x3
> +
> +#define PWRDM_MAX_FUNC_PWRSTS 4
> +
> +#define UNSUP_STATE -1
I think Paul mentioned this in earlier review, but we need to handle (or
be prepared to handle) the inactive state too.
> /* Powerdomain flags */
> #define PWRDM_HAS_HDWR_SAR (1 << 0) /* hardware save-and-restore support */
> @@ -96,7 +108,11 @@ struct powerdomain;
> * @state_counter:
> * @timer:
> * @state_timer:
> - *
> + * @wakeup_lat: wakeup latencies (in us) for possible powerdomain power states
> + * Note about the wakeup latencies ordering: the values must be sorted
> + * in decremental order
> + * @pm_qos_request: PM QOS handle, only used to control the MPU and CORE power
> + * domains states; to be removed when a generic solution is in place.
> * @prcm_partition possible values are defined in mach-omap2/prcm44xx.h.
> */
> struct powerdomain {
> @@ -121,6 +137,8 @@ struct powerdomain {
> s64 timer;
> s64 state_timer[PWRDM_MAX_PWRSTS];
> #endif
> + const u32 wakeup_lat[PWRDM_MAX_FUNC_PWRSTS];
> + struct pm_qos_request_list pm_qos_request;
> };
>
> /**
> @@ -210,6 +228,8 @@ int pwrdm_clkdm_state_switch(struct clockdomain *clkdm);
> int pwrdm_pre_transition(void);
> int pwrdm_post_transition(void);
> int pwrdm_set_lowpwrstchange(struct powerdomain *pwrdm);
> +
> +int pwrdm_wakeuplat_update_pwrst(struct powerdomain *pwrdm, long min_latency);
> u32 pwrdm_get_context_loss_count(struct powerdomain *pwrdm);
>
> extern void omap2xxx_powerdomains_init(void);
Kevin
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