From mboxrd@z Thu Jan 1 00:00:00 1970 From: lina.iyer@linaro.org (Lina Iyer) Date: Thu, 6 Oct 2016 09:54:39 -0600 Subject: [PATCH 3/8] PM / Domains: Allow domain power states to be read from DT In-Reply-To: References: <1475699519-109623-1-git-send-email-lina.iyer@linaro.org> <1475699519-109623-4-git-send-email-lina.iyer@linaro.org> Message-ID: <20161006155439.GE28930@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, Oct 06 2016 at 03:47 -0600, Ulf Hansson wrote: >On 5 October 2016 at 22:31, Lina Iyer wrote: >> This patch allows domains to define idle states in the DT. SoC's can >> define domain idle states in DT using the "domain-idle-states" property >> of the domain provider. Calling of_pm_genpd_init() will read the idle >> states and initialize the genpd for the domain. >> >> In addition to the entry and exit latency for idle state, also add >> residency_ns, param and of_node property to each state. A domain idling >> in a state is only power effecient if it stays idle for a certain period >> in that state. The residency provides this minimum time for the idle >> state to provide power benefits. The param is a state specific u32 value >> that the platform may use for that idle state. >> >> This patch is based on the original patch by Marc Titinger. >> >> Signed-off-by: Marc Titinger >> Signed-off-by: Ulf Hansson >> Signed-off-by: Lina Iyer >> --- >> drivers/base/power/domain.c | 103 ++++++++++++++++++++++++++++++++++++++++++++ >> include/linux/pm_domain.h | 8 ++++ >> 2 files changed, 111 insertions(+) >> >> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c >> index 740afa9..368a5b8 100644 >> --- a/drivers/base/power/domain.c >> +++ b/drivers/base/power/domain.c >> @@ -1895,6 +1895,109 @@ out: >> return ret ? -EPROBE_DEFER : 0; >> } >> EXPORT_SYMBOL_GPL(genpd_dev_pm_attach); >> + >> +static const struct of_device_id idle_state_match[] = { >> + { .compatible = "arm,idle-state", }, >> + { } >> +}; >> + >> +static int read_genpd_state(struct genpd_power_state *genpd_state, > >/s/read_genpd_state/genpd_parse_state > Ok. >> + struct device_node *state_node) >> +{ >> + int err = 0; > >No need to assign err to 0. > Will fix. >> + u32 latency; >> + u32 residency; >> + u32 entry_latency, exit_latency; >> + const struct of_device_id *match_id; >> + >> + match_id = of_match_node(idle_state_match, state_node); >> + if (!match_id) >> + return -EINVAL; >> + >> + err = of_property_read_u32(state_node, "entry-latency-us", >> + &entry_latency); >> + if (err) { >> + pr_debug(" * %s missing entry-latency-us property\n", >> + state_node->full_name); >> + return -EINVAL; >> + } >> + >> + err = of_property_read_u32(state_node, "exit-latency-us", >> + &exit_latency); >> + if (err) { >> + pr_debug(" * %s missing exit-latency-us property\n", >> + state_node->full_name); >> + return -EINVAL; >> + } >> + >> + err = of_property_read_u32(state_node, "min-residency-us", &residency); >> + if (!err) >> + genpd_state->residency_ns = 1000 * residency; >> + >> + latency = entry_latency + exit_latency; > >Hmm, this is probably not what you want. > >The genpd governor, via __default_power_down_ok(), already adds the >->power_on_latency_ns and the ->power_off_latency_ns, when it >validates which idle state you are allowed to enter. > Good catch. >> + genpd_state->power_on_latency_ns = 1000 * latency; >> + genpd_state->power_off_latency_ns = 1000 * entry_latency; >> + >> + return 0; >> +} >> + >> +/** >> + * of_genpd_parse_idle_states: Return array of idle states for the genpd. >> + * >> + * @dn: The genpd device node >> + * @states: The pointer to which the state array will be saved. >> + * @n: The count of elements in the array returned from this function. >> + * >> + * Returns the device states parsed from the OF node. The memory for the states >> + * is allocated by this function and is the responsibility of the caller to >> + * free the memory after use. >> + */ >> +int of_genpd_parse_idle_states(struct device_node *dn, >> + struct genpd_power_state **states, int *n) >> +{ >> + struct genpd_power_state *st; >> + struct device_node *np; >> + int i, ret = 0; >> + int count; >> + >> + for (count = 0; ; count++) >> + if (!of_parse_phandle(dn, "domain-idle-states", count)) >> + break; > >I think it's better to use of_count_phandle_with_args() to find out >the number of phandles. > >> + >> + st = kcalloc(count, sizeof(*st), GFP_KERNEL); >> + if (!st) >> + return -ENOMEM; >> + >> + for (i = 0; i < count; i++) { >> + np = of_parse_phandle(dn, "domain-idle-states", i); > >Isn't this a case of when it would be convenient to use the >of_phandle_iterator*() APIs? > >> + if (!np) { >> + ret = -EFAULT; >> + break; >> + } >> + >> + ret = read_genpd_state(&st[i], np); >> + if (ret) { >> + pr_err >> + ("Parsing idle state node %s failed with err %d\n", >> + np->full_name, ret); >> + of_node_put(np); >> + break; >> + } >> + of_node_put(np); >> + } >> + >> + if (ret) { >> + kfree(st); >> + return ret; >> + } >> + >> + *n = count; >> + *states = st; >> + >> + return 0; >> +} >> +EXPORT_SYMBOL(of_genpd_parse_idle_states); >> + >> #endif /* CONFIG_PM_GENERIC_DOMAINS_OF */ >> >> >> diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h >> index c113713..4c9152d 100644 >> --- a/include/linux/pm_domain.h >> +++ b/include/linux/pm_domain.h >> @@ -204,6 +204,8 @@ extern int of_genpd_add_device(struct of_phandle_args *args, >> extern int of_genpd_add_subdomain(struct of_phandle_args *parent, >> struct of_phandle_args *new_subdomain); >> extern struct generic_pm_domain *of_genpd_remove_last(struct device_node *np); >> +extern int of_genpd_parse_idle_states(struct device_node *dn, >> + struct genpd_power_state **states, int *n); >> >> int genpd_dev_pm_attach(struct device *dev); >> #else /* !CONFIG_PM_GENERIC_DOMAINS_OF */ >> @@ -233,6 +235,12 @@ static inline int of_genpd_add_subdomain(struct of_phandle_args *parent, >> return -ENODEV; >> } >> >> +static inline int of_genpd_parse_idle_states(struct device_node *dn, >> + struct genpd_power_state **states, int *n) >> +{ >> + return -ENODEV; >> +} >> + >> static inline int genpd_dev_pm_attach(struct device *dev) >> { >> return -ENODEV; >> -- >> 2.7.4 >> > >Kind regards >Uffe