Re: [RFC PATCH v4 5/8] cpuidle: Factor-out power domain related code from PSCI domain driver
From: Ulf Hansson <hidden>
Date: 2021-05-24 18:01:56
Also in:
linux-arm-kernel, linux-pm, linux-riscv, lkml
On Mon, 17 May 2021 at 15:10, Anup Patel [off-list ref] wrote:
The generic power domain related code in PSCI domain driver is largely independent of PSCI and can be shared with RISC-V SBI domain driver hence we factor-out this code into dt_idle_genpd.c and dt_idle_genpd.h. Signed-off-by: Anup Patel <redacted>
This is clearly a big step in the right direction. Just a couple minor things, see more below. Note that, I have a couple of patches in the pipe for the cpuidle-psci-domain driver (not ready to be posted). I need a couple of more days to confirm this restructuring still makes sense beyond these potential new changes. I will let you know as soon as I can with the outcome. [...]
quoted hunk ↗ jump to hunk
diff --git a/drivers/cpuidle/dt_idle_genpd.c b/drivers/cpuidle/dt_idle_genpd.c
I think it would be a good idea to add a new section for this to the MAINTAINERS file. Perhaps a "DT IDLE DOMAIN" section? Or perhaps you have another idea? In any case, I am happy to continue with maintenance of this code, even in the new restructured form.
quoted hunk ↗ jump to hunk
new file mode 100644 index 000000000000..5a901773db60--- /dev/null +++ b/drivers/cpuidle/dt_idle_genpd.c@@ -0,0 +1,182 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * PM domains for CPUs via genpd. + * + * Copyright (C) 2019 Linaro Ltd. + * Author: Ulf Hansson <ulf.hansson@linaro.org> + * + * Copyright (c) 2021 Western Digital Corporation or its affiliates. + */ + +#define pr_fmt(fmt) "dt-idle-genpd: " fmt + +#include <linux/cpu.h> +#include <linux/device.h> +#include <linux/kernel.h> +#include <linux/pm_domain.h> +#include <linux/pm_runtime.h> +#include <linux/slab.h> +#include <linux/string.h> + +#include "dt_idle_genpd.h" + +static int dt_pd_parse_state_nodes( + int (*parse_state)(struct device_node *, u32 *), + struct genpd_power_state *states, int state_count) +{ + int i, ret; + u32 state, *state_buf; + + for (i = 0; i < state_count; i++) { + ret = parse_state(to_of_node(states[i].fwnode), &state); + if (ret) + goto free_state; + + state_buf = kmalloc(sizeof(u32), GFP_KERNEL); + if (!state_buf) { + ret = -ENOMEM; + goto free_state; + } + *state_buf = state; + states[i].data = state_buf; + } + + return 0; + +free_state: + i--; + for (; i >= 0; i--) + kfree(states[i].data); + return ret; +} + +static int dt_pd_parse_states(struct device_node *np, + int (*parse_state)(struct device_node *, u32 *), + 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 dt specifics for each found state. */ + ret = dt_pd_parse_state_nodes(parse_state, *states, *state_count); + if (ret) + kfree(*states); + + return ret; +} + +static void dt_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); +} + +void dt_pd_free(struct generic_pm_domain *pd) +{ + dt_pd_free_states(pd->states, pd->state_count); + kfree(pd->name); + kfree(pd); +} +EXPORT_SYMBOL_GPL(dt_pd_free); + +struct generic_pm_domain *dt_pd_alloc(struct device_node *np, + int (*parse_state)(struct device_node *, u32 *)) +{ + struct generic_pm_domain *pd; + struct genpd_power_state *states = NULL; + int ret, state_count = 0; + + pd = kzalloc(sizeof(*pd), GFP_KERNEL); + if (!pd) + goto out; + + pd->name = kasprintf(GFP_KERNEL, "%pOF", np); + if (!pd->name) + goto free_pd; + + /* + * Parse the domain idle states and let genpd manage the state selection + * for those being compatible with "domain-idle-state". + */ + ret = dt_pd_parse_states(np, parse_state, &states, &state_count); + if (ret) + goto free_name; + + pd->free_states = dt_pd_free_states; + pd->name = kbasename(pd->name); + pd->states = states; + pd->state_count = state_count; + + pr_debug("alloc PM domain %s\n", pd->name); + return pd; + +free_name: + kfree(pd->name); +free_pd: + kfree(pd); +out: + pr_err("failed to alloc PM domain %pOF\n", np); + return NULL; +} +EXPORT_SYMBOL_GPL(dt_pd_alloc); + +int dt_pd_init_topology(struct device_node *np) +{ + 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 = of_genpd_add_subdomain(&parent, &child); + of_node_put(parent.np); + if (ret) { + of_node_put(node); + return ret; + } + } + + return 0; +} +EXPORT_SYMBOL_GPL(dt_pd_init_topology);
May I suggest that we stick to dt_idle_* as the prefix for all of the exported functions in this file. Static functions can just skip the prefix altogether.
+
+struct device *dt_idle_genpd_attach_cpu(int cpu, const char *name)
+{
+ struct device *dev;
+
+ dev = dev_pm_domain_attach_by_name(get_cpu_device(cpu), name);
+ if (IS_ERR_OR_NULL(dev))
+ return dev;
+
+ pm_runtime_irq_safe(dev);
+ if (cpu_online(cpu))
+ pm_runtime_get_sync(dev);
+
+ dev_pm_syscore_device(dev, true);
+
+ return dev;
+}
+EXPORT_SYMBOL_GPL(dt_idle_genpd_attach_cpu);
+
+void dt_idle_genpd_detach_cpu(struct device *dev)
+{
+ if (IS_ERR_OR_NULL(dev))
+ return;
+
+ dev_pm_domain_detach(dev, false);
+}
+EXPORT_SYMBOL_GPL(dt_idle_genpd_detach_cpu);Again, a minor comment on the naming of the functions. How about skipping "genpd" in the prefix, thus just dt_idle_attach|detach_cpu()? [...] Kind regards Uffe