On Mon, Dec 30, 2019 at 03:44:01PM +0100, Ulf Hansson wrote:
> When the hierarchical CPU topology layout is used in DT and the PSCI OSI
> mode is supported by the PSCI FW, let's initialize a corresponding PM
> domain topology by using genpd. This enables a CPU and a group of CPUs,
> when attached to the topology, to be power-managed accordingly.
>
> To trigger the attempt to initialize the genpd data structures let's use a
> subsys_initcall, which should be early enough to allow CPUs, but also other
> devices to be attached.
>
> The initialization consists of parsing the PSCI OF node for the topology
> and the "domain idle states" DT bindings. In case the idle states are
> compatible with "domain-idle-state", the initialized genpd becomes
> responsible of selecting an idle state for the PM domain, via assigning it
> a genpd governor.
>
> Note that, a successful initialization of the genpd data structures, is
> followed by a call to psci_set_osi_mode(), as to try to enable the OSI mode
> in the PSCI FW. In case this fails, we fall back into a degraded mode
> rather than bailing out and returning error codes.
>
> Co-developed-by: Lina Iyer <lina.iyer@xxxxxxxxxx>
> Signed-off-by: Lina Iyer <lina.iyer@xxxxxxxxxx>
> Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> ---
>
> Changes in v5:
> - Remove genpds in the error path, when enabling OSI failed.
> - Let psci_dt_attach_cpu() return NULL if OSI mode isn't enabled.
> - Make the osi_mode_enabled variable __initdata.
> - Drop some DT compatible strings, as PSCI v1.0 introduces OSI.
>
> ---
> drivers/cpuidle/cpuidle-psci-domain.c | 277 ++++++++++++++++++++++++++
> drivers/cpuidle/cpuidle-psci.c | 4 +-
> drivers/cpuidle/cpuidle-psci.h | 5 +
> 3 files changed, 284 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/cpuidle/cpuidle-psci-domain.c b/drivers/cpuidle/cpuidle-psci-domain.c
> index 87f881c21af1..423f03bbeb74 100644
> --- a/drivers/cpuidle/cpuidle-psci-domain.c
> +++ b/drivers/cpuidle/cpuidle-psci-domain.c
> @@ -7,18 +7,295 @@
> *
> */
>
> +#define pr_fmt(fmt) "CPUidle PSCI: " fmt
> +
Looks like a candidate for cpuidle-psci.h so that it's effective even for
cpuidle-psci.c, if you re-spin(I don't see any reasons to) or if you are
sending PR, you can fix-up this along with dropping data->dev :)
Anyways,
Reviewed-by: Sudeep Holla <sudeep.holla@xxxxxxx>
> #include <linux/cpu.h>
> #include <linux/device.h>
> #include <linux/kernel.h>
> #include <linux/pm_domain.h>
> #include <linux/pm_runtime.h>
> +#include <linux/psci.h>
> +#include <linux/slab.h>
> +#include <linux/string.h>
>
> #include "cpuidle-psci.h"
>
> +struct psci_pd_provider {
> + struct list_head link;
> + struct device_node *node;
> +};
> +
> +static LIST_HEAD(psci_pd_providers);
> +static bool osi_mode_enabled __initdata;
> +
> +static int psci_pd_power_off(struct generic_pm_domain *pd)
> +{
> + struct genpd_power_state *state = &pd->states[pd->state_idx];
> + u32 *pd_state;
> +
> + if (!state->data)
> + return 0;
> +
> + /* OSI mode is enabled, set the corresponding domain state. */
> + pd_state = state->data;
> + psci_set_domain_state(*pd_state);
> +
> + return 0;
> +}
> +
> +static int __init psci_pd_parse_state_nodes(struct genpd_power_state *states,
> + int state_count)
> +{
> + int i, ret;
> + u32 psci_state, *psci_state_buf;
> +
> + for (i = 0; i < state_count; i++) {
> + ret = psci_dt_parse_state_node(to_of_node(states[i].fwnode),
> + &psci_state);
> + if (ret)
> + goto free_state;
> +
> + psci_state_buf = kmalloc(sizeof(u32), GFP_KERNEL);
> + if (!psci_state_buf) {
> + ret = -ENOMEM;
> + goto free_state;
> + }
> + *psci_state_buf = psci_state;
> + states[i].data = psci_state_buf;
> + }
> +
> + return 0;
> +
> +free_state:
> + i--;
> + for (; i >= 0; i--)
> + kfree(states[i].data);
> + return ret;
> +}
> +
> +static int __init psci_pd_parse_states(struct device_node *np,
> + struct genpd_power_state **states, int *state_count)
> +{
> + int ret;
> +
> + /* Parse the domain idle states. */
> + ret = of_genpd_parse_idle_states(np, states, state_count);
> + if (ret)
> + return ret;
> +
> + /* Fill out the PSCI specifics for each found state. */
> + ret = psci_pd_parse_state_nodes(*states, *state_count);
> + if (ret)
> + kfree(*states);
> +
> + return ret;
> +}
> +
> +static void psci_pd_free_states(struct genpd_power_state *states,
> + unsigned int state_count)
> +{
> + int i;
> +
> + for (i = 0; i < state_count; i++)
> + kfree(states[i].data);
> + kfree(states);
> +}
> +
> +static int __init psci_pd_init(struct device_node *np)
> +{
> + struct generic_pm_domain *pd;
> + struct psci_pd_provider *pd_provider;
> + struct dev_power_governor *pd_gov;
> + struct genpd_power_state *states = NULL;
> + int ret = -ENOMEM, state_count = 0;
> +
> + pd = kzalloc(sizeof(*pd), GFP_KERNEL);
> + if (!pd)
> + goto out;
> +
> + pd_provider = kzalloc(sizeof(*pd_provider), GFP_KERNEL);
> + if (!pd_provider)
> + goto free_pd;
> +
> + pd->name = kasprintf(GFP_KERNEL, "%pOF", np);
> + if (!pd->name)
> + goto free_pd_prov;
> +
> + /*
> + * Parse the domain idle states and let genpd manage the state selection
> + * for those being compatible with "domain-idle-state".
> + */
> + ret = psci_pd_parse_states(np, &states, &state_count);
> + if (ret)
> + goto free_name;
> +
> + pd->free_states = psci_pd_free_states;
> + pd->name = kbasename(pd->name);
> + pd->power_off = psci_pd_power_off;
> + pd->states = states;
> + pd->state_count = state_count;
> + pd->flags |= GENPD_FLAG_IRQ_SAFE | GENPD_FLAG_CPU_DOMAIN;
> +
> + /* Use governor for CPU PM domains if it has some states to manage. */
> + pd_gov = state_count > 0 ? &pm_domain_cpu_gov : NULL;
> +
> + ret = pm_genpd_init(pd, pd_gov, false);
> + if (ret) {
> + psci_pd_free_states(states, state_count);
> + goto free_name;
> + }
> +
> + ret = of_genpd_add_provider_simple(np, pd);
> + if (ret)
> + goto remove_pd;
> +
> + pd_provider->node = of_node_get(np);
> + list_add(&pd_provider->link, &psci_pd_providers);
> +
> + pr_debug("init PM domain %s\n", pd->name);
> + return 0;
> +
> +remove_pd:
> + pm_genpd_remove(pd);
> +free_name:
> + kfree(pd->name);
> +free_pd_prov:
> + kfree(pd_provider);
> +free_pd:
> + kfree(pd);
> +out:
> + pr_err("failed to init PM domain ret=%d %pOF\n", ret, np);
> + return ret;
> +}
> +
> +static void __init psci_pd_remove(void)
> +{
> + struct psci_pd_provider *pd_provider, *it;
> + struct generic_pm_domain *genpd;
> +
> + list_for_each_entry_safe(pd_provider, it, &psci_pd_providers, link) {
> + of_genpd_del_provider(pd_provider->node);
> +
> + genpd = of_genpd_remove_last(pd_provider->node);
> + if (!IS_ERR(genpd))
> + kfree(genpd);
> +
> + of_node_put(pd_provider->node);
> + list_del(&pd_provider->link);
> + kfree(pd_provider);
> + }
> +}
> +
> +static int __init psci_pd_init_topology(struct device_node *np, bool add)
> +{
> + struct device_node *node;
> + struct of_phandle_args child, parent;
> + int ret;
> +
> + for_each_child_of_node(np, node) {
> + if (of_parse_phandle_with_args(node, "power-domains",
> + "#power-domain-cells", 0, &parent))
> + continue;
> +
> + child.np = node;
> + child.args_count = 0;
> +
> + ret = add ? of_genpd_add_subdomain(&parent, &child) :
> + of_genpd_remove_subdomain(&parent, &child);
> + of_node_put(parent.np);
> + if (ret) {
> + of_node_put(node);
> + return ret;
> + }
> + }
> +
> + return 0;
> +}
> +
> +static int __init psci_pd_add_topology(struct device_node *np)
> +{
> + return psci_pd_init_topology(np, true);
> +}
> +
> +static void __init psci_pd_remove_topology(struct device_node *np)
> +{
> + psci_pd_init_topology(np, false);
> +}
> +
> +static const struct of_device_id psci_of_match[] __initconst = {
> + { .compatible = "arm,psci-1.0" },
> + {}
> +};
> +
> +static int __init psci_idle_init_domains(void)
> +{
> + struct device_node *np = of_find_matching_node(NULL, psci_of_match);
> + struct device_node *node;
> + int ret = 0, pd_count = 0;
> +
> + if (!np)
> + return -ENODEV;
> +
> + /* Currently limit the hierarchical topology to be used in OSI mode. */
> + if (!psci_has_osi_support())
> + goto out;
> +
> + /*
> + * Parse child nodes for the "#power-domain-cells" property and
> + * initialize a genpd/genpd-of-provider pair when it's found.
> + */
> + for_each_child_of_node(np, node) {
> + if (!of_find_property(node, "#power-domain-cells", NULL))
> + continue;
> +
> + ret = psci_pd_init(node);
> + if (ret)
> + goto put_node;
> +
> + pd_count++;
> + }
> +
> + /* Bail out if not using the hierarchical CPU topology. */
> + if (!pd_count)
> + goto out;
> +
> + /* Link genpd masters/subdomains to model the CPU topology. */
> + ret = psci_pd_add_topology(np);
> + if (ret)
> + goto remove_pd;
> +
> + /* Try to enable OSI mode. */
> + ret = psci_set_osi_mode();
> + if (ret) {
> + pr_warn("failed to enable OSI mode: %d\n", ret);
> + psci_pd_remove_topology(np);
> + goto remove_pd;
> + }
> +
> + osi_mode_enabled = true;
> + of_node_put(np);
> + pr_info("Initialized CPU PM domain topology\n");
> + return pd_count;
> +
> +put_node:
> + of_node_put(node);
> +remove_pd:
> + if (pd_count)
> + psci_pd_remove();
> + pr_err("failed to create CPU PM domains ret=%d\n", ret);
> +out:
> + of_node_put(np);
> + return ret;
> +}
> +subsys_initcall(psci_idle_init_domains);
> +
> struct device __init *psci_dt_attach_cpu(int cpu)
> {
> struct device *dev;
>
> + if (!osi_mode_enabled)
> + return NULL;
> +
> dev = dev_pm_domain_attach_by_name(get_cpu_device(cpu), "psci");
> if (IS_ERR_OR_NULL(dev))
> return dev;
> diff --git a/drivers/cpuidle/cpuidle-psci.c b/drivers/cpuidle/cpuidle-psci.c
> index 9d779be27071..edd7a54ef0d3 100644
> --- a/drivers/cpuidle/cpuidle-psci.c
> +++ b/drivers/cpuidle/cpuidle-psci.c
> @@ -34,7 +34,7 @@ static DEFINE_PER_CPU_READ_MOSTLY(struct psci_cpuidle_data, psci_cpuidle_data);
> static DEFINE_PER_CPU(u32, domain_state);
> static bool psci_cpuidle_use_cpuhp __initdata;
>
> -static inline void psci_set_domain_state(u32 state)
> +void psci_set_domain_state(u32 state)
> {
> __this_cpu_write(domain_state, state);
> }
> @@ -143,7 +143,7 @@ static const struct of_device_id psci_idle_state_match[] __initconst = {
> { },
> };
>
> -static int __init psci_dt_parse_state_node(struct device_node *np, u32 *state)
> +int __init psci_dt_parse_state_node(struct device_node *np, u32 *state)
> {
> int err = of_property_read_u32(np, "arm,psci-suspend-param", state);
>
> diff --git a/drivers/cpuidle/cpuidle-psci.h b/drivers/cpuidle/cpuidle-psci.h
> index 8609482cf490..7299a04dd467 100644
> --- a/drivers/cpuidle/cpuidle-psci.h
> +++ b/drivers/cpuidle/cpuidle-psci.h
> @@ -3,6 +3,11 @@
> #ifndef __CPUIDLE_PSCI_H
> #define __CPUIDLE_PSCI_H
>
> +struct device_node;
> +
> +void psci_set_domain_state(u32 state);
> +int __init psci_dt_parse_state_node(struct device_node *np, u32 *state);
> +
> #ifdef CONFIG_PM_GENERIC_DOMAINS_OF
> struct device __init *psci_dt_attach_cpu(int cpu);
> #else
> --
> 2.17.1
>
