[PATCH v3 2/3] cpuidle: riscv-sbi: Work with the external pmdomain driver

[Nick Hu]

To work with the external pmdomain driver, exposing the
`sbi_cpuidle_pd_power_off` and `sbi_dt_parse_state_node` so the external
pmdomain driver can parse the riscv idle state data and set the domain
idle state where powering off. In addition, separate the genpd init and
the idle driver init. The genpd remains functional even when the idle
state is absent.

Co-developed-by: Samuel Holland <samuel.holland at sifive.com>
Signed-off-by: Samuel Holland <samuel.holland at sifive.com>
Signed-off-by: Nick Hu <nick.hu at sifive.com>
---
 drivers/cpuidle/cpuidle-riscv-sbi.c | 46 ++++++++++++++++++-----------
 drivers/cpuidle/cpuidle-riscv-sbi.h | 20 +++++++++++++
 2 files changed, 48 insertions(+), 18 deletions(-)
 create mode 100644 drivers/cpuidle/cpuidle-riscv-sbi.h

diff --git a/drivers/cpuidle/cpuidle-riscv-sbi.c b/drivers/cpuidle/cpuidle-riscv-sbi.c
index 0fe1ece9fbdc..be3949971eed 100644
--- a/drivers/cpuidle/cpuidle-riscv-sbi.c
+++ b/drivers/cpuidle/cpuidle-riscv-sbi.c
@@ -27,6 +27,7 @@
 #include <asm/suspend.h>
 
 #include "cpuidle.h"
+#include "cpuidle-riscv-sbi.h"
 #include "dt_idle_states.h"
 #include "dt_idle_genpd.h"
 
@@ -43,7 +44,6 @@ struct sbi_domain_state {
 static DEFINE_PER_CPU_READ_MOSTLY(struct sbi_cpuidle_data, sbi_cpuidle_data);
 static DEFINE_PER_CPU(struct sbi_domain_state, domain_state);
 static bool sbi_cpuidle_use_osi;
-static bool sbi_cpuidle_use_cpuhp;
 static bool sbi_cpuidle_pd_allow_domain_state;
 
 static inline void sbi_set_domain_state(u32 state)
@@ -171,9 +171,6 @@ static void sbi_idle_init_cpuhp(void)
 {
 	int err;
 
-	if (!sbi_cpuidle_use_cpuhp)
-		return;
-
 	err = cpuhp_setup_state_nocalls(CPUHP_AP_CPU_PM_STARTING,
 					"cpuidle/sbi:online",
 					sbi_cpuidle_cpuhp_up,
@@ -188,7 +185,7 @@ static const struct of_device_id sbi_cpuidle_state_match[] = {
 	{ },
 };
 
-static int sbi_dt_parse_state_node(struct device_node *np, u32 *state)
+int sbi_dt_parse_state_node(struct device_node *np, u32 *state)
 {
 	int err = of_property_read_u32(np, "riscv,sbi-suspend-param", state);
 
@@ -213,10 +210,6 @@ static int sbi_dt_cpu_init_topology(struct cpuidle_driver *drv,
 	if (!sbi_cpuidle_use_osi)
 		return 0;
 
-	data->dev = dt_idle_attach_cpu(cpu, "sbi");
-	if (IS_ERR_OR_NULL(data->dev))
-		return PTR_ERR_OR_ZERO(data->dev);
-
 	/*
 	 * Using the deepest state for the CPU to trigger a potential selection
 	 * of a shared state for the domain, assumes the domain states are all
@@ -226,7 +219,6 @@ static int sbi_dt_cpu_init_topology(struct cpuidle_driver *drv,
 	drv->states[state_count - 1].enter = sbi_enter_domain_idle_state;
 	drv->states[state_count - 1].enter_s2idle =
 					sbi_enter_s2idle_domain_idle_state;
-	sbi_cpuidle_use_cpuhp = true;
 
 	return 0;
 }
@@ -282,7 +274,6 @@ static void sbi_cpuidle_deinit_cpu(int cpu)
 	struct sbi_cpuidle_data *data = per_cpu_ptr(&sbi_cpuidle_data, cpu);
 
 	dt_idle_detach_cpu(data->dev);
-	sbi_cpuidle_use_cpuhp = false;
 }
 
 static int sbi_cpuidle_init_cpu(struct device *dev, int cpu)
@@ -325,8 +316,9 @@ static int sbi_cpuidle_init_cpu(struct device *dev, int cpu)
 	/* Initialize idle states from DT. */
 	ret = sbi_cpuidle_dt_init_states(dev, drv, cpu, state_count);
 	if (ret) {
-		pr_err("HART%ld: failed to init idle states\n",
-		       cpuid_to_hartid_map(cpu));
+		if (ret != -EPROBE_DEFER)
+			pr_err("HART%ld: failed to init idle states\n",
+			       cpuid_to_hartid_map(cpu));
 		return ret;
 	}
 
@@ -356,7 +348,7 @@ static void sbi_cpuidle_domain_sync_state(struct device *dev)
 
 #ifdef CONFIG_DT_IDLE_GENPD
 
-static int sbi_cpuidle_pd_power_off(struct generic_pm_domain *pd)
+int sbi_cpuidle_pd_power_off(struct generic_pm_domain *pd)
 {
 	struct genpd_power_state *state = &pd->states[pd->state_idx];
 	u32 *pd_state;
@@ -529,6 +521,27 @@ static int sbi_cpuidle_probe(struct platform_device *pdev)
 			return ret;
 	}
 
+	/* Attaching the cpu to the corresponding power domain */
+	if (sbi_cpuidle_use_osi) {
+		for_each_present_cpu(cpu) {
+			struct sbi_cpuidle_data *data = per_cpu_ptr(&sbi_cpuidle_data, cpu);
+
+			data->dev = dt_idle_attach_cpu(cpu, "sbi");
+			if (IS_ERR_OR_NULL(data->dev)) {
+				ret = PTR_ERR_OR_ZERO(data->dev);
+				if (ret != -EPROBE_DEFER)
+					pr_debug("Hart%ld: fail to attach the power domain\n",
+						 cpuid_to_hartid_map(cpu));
+
+				while (--cpu >= 0)
+					dt_idle_detach_cpu(data->dev);
+				return ret;
+			}
+		}
+		/* Setup CPU hotplut notifiers */
+		sbi_idle_init_cpuhp();
+	}
+
 	/* Initialize CPU idle driver for each present CPU */
 	for_each_present_cpu(cpu) {
 		ret = sbi_cpuidle_init_cpu(&pdev->dev, cpu);
@@ -539,9 +552,6 @@ static int sbi_cpuidle_probe(struct platform_device *pdev)
 		}
 	}
 
-	/* Setup CPU hotplut notifiers */
-	sbi_idle_init_cpuhp();
-
 	if (cpuidle_disabled())
 		pr_info("cpuidle is disabled\n");
 	else
@@ -556,7 +566,7 @@ static int sbi_cpuidle_probe(struct platform_device *pdev)
 		cpuidle_unregister(drv);
 		sbi_cpuidle_deinit_cpu(cpu);
 	}
-
+out:
 	return ret;
 }
 
diff --git a/drivers/cpuidle/cpuidle-riscv-sbi.h b/drivers/cpuidle/cpuidle-riscv-sbi.h
new file mode 100644
index 000000000000..f39186b65a10
--- /dev/null
+++ b/drivers/cpuidle/cpuidle-riscv-sbi.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __CPUIDLE_RISCV_SBI
+#define __CPUIDLE_RISCV_SBI
+
+#ifdef CONFIG_DT_IDLE_GENPD
+
+int sbi_cpuidle_pd_power_off(struct generic_pm_domain *pd);
+
+#else
+
+static inline int sbi_cpuidle_pd_power_off(struct generic_pm_domain *pd)
+{
+	return 0;
+}
+
+#endif
+
+int sbi_dt_parse_state_node(struct device_node *np, u32 *state);
+
+#endif
-- 
2.17.1