| Message ID | 1475699519-109623-2-git-send-email-lina.iyer@linaro.org |
|---|---|
| State | New |
| Headers | show |
On Thu, Oct 06 2016 at 02:37 -0600, Ulf Hansson wrote: >On 5 October 2016 at 22:31, Lina Iyer <lina.iyer@linaro.org> wrote: >> Allow PM Domain states to be defined dynamically by the drivers. This >> removes the limitation on the maximum number of states possible for a >> domain. >> >> Cc: Axel Haslam <ahaslam+renesas@baylibre.com> >> Suggested-by: Ulf Hansson <ulf.hansson@linaro.org> >> Signed-off-by: Lina Iyer <lina.iyer@linaro.org> <...> >> -#define GENPD_MAX_NUM_STATES 8 /* Number of possible low power states */ >> - >> enum gpd_status { >> GPD_STATE_ACTIVE = 0, /* PM domain is active */ >> GPD_STATE_POWER_OFF, /* PM domain is off */ >> @@ -70,7 +68,7 @@ struct generic_pm_domain { >> void (*detach_dev)(struct generic_pm_domain *domain, >> struct device *dev); >> unsigned int flags; /* Bit field of configs for genpd */ >> - struct genpd_power_state states[GENPD_MAX_NUM_STATES]; >> + struct genpd_power_state *states; >> unsigned int state_count; /* number of states */ >> unsigned int state_idx; /* state that genpd will go to when off */ >> >> -- >> 2.7.4 >> > >In general I like the improvement, but.. > >This change implies that ->states may very well be NULL. This isn't >validated by genpd's internal logic when power off/on the domain >(genpd_power_on|off(), __default_power_down_ok()). You need to fix >this, somehow. > Good point. >Perhaps the easiest solutions is, when pm_genpd_init() finds that >->state is NULL, that we allocate a struct genpd_power_state with >array size of 1 and assign it to ->states. Although, doing this also >means you need to track that genpd was responsible for the the >allocation, so it must also free the data from within genpd_remove(). > >Unless you have other ideas!? > I can think of some hacks, but they are uglier than the problem we are trying to solve. We could drop this patch. Real world situations would not have more than 8 states and if there is one, we can think about it then. Thanks, Lina -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Oct 06 2016 at 13:45 -0600, Ulf Hansson wrote: >On 6 October 2016 at 17:40, Lina Iyer <lina.iyer@linaro.org> wrote: >> On Thu, Oct 06 2016 at 02:37 -0600, Ulf Hansson wrote: >>> >>> On 5 October 2016 at 22:31, Lina Iyer <lina.iyer@linaro.org> wrote: >>>> >>>> Allow PM Domain states to be defined dynamically by the drivers. This >>>> removes the limitation on the maximum number of states possible for a >>>> domain. >>>> >>>> Cc: Axel Haslam <ahaslam+renesas@baylibre.com> >>>> Suggested-by: Ulf Hansson <ulf.hansson@linaro.org> >>>> Signed-off-by: Lina Iyer <lina.iyer@linaro.org> >> >> <...> >>>> >>>> -#define GENPD_MAX_NUM_STATES 8 /* Number of possible low power states >>>> */ >>>> - >>>> enum gpd_status { >>>> GPD_STATE_ACTIVE = 0, /* PM domain is active */ >>>> GPD_STATE_POWER_OFF, /* PM domain is off */ >>>> @@ -70,7 +68,7 @@ struct generic_pm_domain { >>>> void (*detach_dev)(struct generic_pm_domain *domain, >>>> struct device *dev); >>>> unsigned int flags; /* Bit field of configs for genpd >>>> */ >>>> - struct genpd_power_state states[GENPD_MAX_NUM_STATES]; >>>> + struct genpd_power_state *states; >>>> unsigned int state_count; /* number of states */ >>>> unsigned int state_idx; /* state that genpd will go to when off >>>> */ >>>> >>>> -- >>>> 2.7.4 >>>> >>> >>> In general I like the improvement, but.. >>> >>> This change implies that ->states may very well be NULL. This isn't >>> validated by genpd's internal logic when power off/on the domain >>> (genpd_power_on|off(), __default_power_down_ok()). You need to fix >>> this, somehow. >>> >> Good point. >> >>> Perhaps the easiest solutions is, when pm_genpd_init() finds that >>> ->state is NULL, that we allocate a struct genpd_power_state with >>> array size of 1 and assign it to ->states. Although, doing this also >>> means you need to track that genpd was responsible for the the >>> allocation, so it must also free the data from within genpd_remove(). >>> >>> Unless you have other ideas!? >>> >> I can think of some hacks, but they are uglier than the problem we are >> trying to solve. We could drop this patch. Real world situations would >> not have more than 8 states and if there is one, we can think about it >> then. > >The problem with the current approach is that we waste some memory as >we always have an array of 8 states per genpd. In the worst case, >which currently is the most common case, only 1 out of 8 states is >being used. > >So, let's not be lazy here and instead take the opportunity to fix >this, and especially I think this makes sense, before we go on and add >the DT parsing of the domain-idle-states. > Hmm.. We are not wasting much memory in comparison, but if you insist, sure. >The more sophisticated method would probably be to use kobject/kref, >but let's not go there for now. Instead let's try an easy method of >just tracking whether the allocations had been made internally by >genpd, via adding a "bool state_allocated to the struct >generic_pm_domain. Would that work? > It would work. i. How about an additional static state by default in the domain structure, if the platform does not provide a state then the default structure is used. That way we dont have to track it. But it does waste memory eqivalent to a state, when there are states provided by the platform. ii. I could add a void *free to the domain structure and save the memory allocated by default in the *free. At domain remove, we just do a kfree on free. iii. Use a boolean flag. Thanks, Lina -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/arm/mach-imx/gpc.c b/arch/arm/mach-imx/gpc.c index 0df062d..b92dad5 100644 --- a/arch/arm/mach-imx/gpc.c +++ b/arch/arm/mach-imx/gpc.c @@ -380,13 +380,6 @@ static struct pu_domain imx6q_pu_domain = { .name = "PU", .power_off = imx6q_pm_pu_power_off, .power_on = imx6q_pm_pu_power_on, - .states = { - [0] = { - .power_off_latency_ns = 25000, - .power_on_latency_ns = 2000000, - }, - }, - .state_count = 1, }, }; @@ -430,6 +423,16 @@ static int imx_gpc_genpd_init(struct device *dev, struct regulator *pu_reg) if (!IS_ENABLED(CONFIG_PM_GENERIC_DOMAINS)) return 0; + imx6q_pu_domain.base.states = devm_kzalloc(dev, + sizeof(*imx6q_pu_domain.base.states), + GFP_KERNEL); + if (!imx6q_pu_domain.base.states) + return -ENOMEM; + + imx6q_pu_domain.base.states[0].power_off_latency_ns = 25000; + imx6q_pu_domain.base.states[0].power_on_latency_ns = 2000000; + mx6q_pu_domain.base.state_count = 1, + pm_genpd_init(&imx6q_pu_domain.base, NULL, false); return of_genpd_add_provider_onecell(dev->of_node, &imx_gpc_onecell_data); diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c index e023066..740afa9 100644 --- a/drivers/base/power/domain.c +++ b/drivers/base/power/domain.c @@ -1325,16 +1325,6 @@ int pm_genpd_init(struct generic_pm_domain *genpd, genpd->dev_ops.start = pm_clk_resume; } - if (genpd->state_idx >= GENPD_MAX_NUM_STATES) { - pr_warn("Initial state index out of bounds.\n"); - genpd->state_idx = GENPD_MAX_NUM_STATES - 1; - } - - if (genpd->state_count > GENPD_MAX_NUM_STATES) { - pr_warn("Limiting states to %d\n", GENPD_MAX_NUM_STATES); - genpd->state_count = GENPD_MAX_NUM_STATES; - } - /* Use only one "off" state if there were no states declared */ if (genpd->state_count == 0) genpd->state_count = 1; diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h index a09fe5c..bd1ffb9 100644 --- a/include/linux/pm_domain.h +++ b/include/linux/pm_domain.h @@ -19,8 +19,6 @@ /* Defines used for the flags field in the struct generic_pm_domain */ #define GENPD_FLAG_PM_CLK (1U << 0) /* PM domain uses PM clk */ -#define GENPD_MAX_NUM_STATES 8 /* Number of possible low power states */ - enum gpd_status { GPD_STATE_ACTIVE = 0, /* PM domain is active */ GPD_STATE_POWER_OFF, /* PM domain is off */ @@ -70,7 +68,7 @@ struct generic_pm_domain { void (*detach_dev)(struct generic_pm_domain *domain, struct device *dev); unsigned int flags; /* Bit field of configs for genpd */ - struct genpd_power_state states[GENPD_MAX_NUM_STATES]; + struct genpd_power_state *states; unsigned int state_count; /* number of states */ unsigned int state_idx; /* state that genpd will go to when off */
Allow PM Domain states to be defined dynamically by the drivers. This removes the limitation on the maximum number of states possible for a domain. Cc: Axel Haslam <ahaslam+renesas@baylibre.com> Suggested-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Lina Iyer <lina.iyer@linaro.org> --- arch/arm/mach-imx/gpc.c | 17 ++++++++++------- drivers/base/power/domain.c | 10 ---------- include/linux/pm_domain.h | 4 +--- 3 files changed, 11 insertions(+), 20 deletions(-) -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html