cpuidle: RISC-V: Move few functions to arch/riscv

To support ACPI Low Power Idle (LPI), few functions are required which
are currently static functions in the DT based cpuidle driver. Hence,
move them under arch/riscv so that ACPI driver also can use them. Since
they are no longer static functions, append "riscv_" prefix to the
function name.

Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20240118062930.245937-2-sunilvl@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

arch/riscv/include/asm/suspend.h

@@ -55,4 +55,7 @@ int hibernate_resume_nonboot_cpu_disable(void);
 asmlinkage void hibernate_restore_image(unsigned long resume_satp, unsigned long satp_temp,
 					unsigned long cpu_resume);
 asmlinkage int hibernate_core_restore_code(void);
+bool riscv_sbi_hsm_is_supported(void);
+bool riscv_sbi_suspend_state_is_valid(u32 state);
+int riscv_sbi_hart_suspend(u32 state);
 #endif

arch/riscv/kernel/suspend.c

@@ -128,4 +128,53 @@ static int __init sbi_system_suspend_init(void)
 }
 
 arch_initcall(sbi_system_suspend_init);
+
+static int sbi_suspend_finisher(unsigned long suspend_type,
+				unsigned long resume_addr,
+				unsigned long opaque)
+{
+	struct sbiret ret;
+
+	ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_SUSPEND,
+			suspend_type, resume_addr, opaque, 0, 0, 0);
+
+	return (ret.error) ? sbi_err_map_linux_errno(ret.error) : 0;
+}
+
+int riscv_sbi_hart_suspend(u32 state)
+{
+	if (state & SBI_HSM_SUSP_NON_RET_BIT)
+		return cpu_suspend(state, sbi_suspend_finisher);
+	else
+		return sbi_suspend_finisher(state, 0, 0);
+}
+
+bool riscv_sbi_suspend_state_is_valid(u32 state)
+{
+	if (state > SBI_HSM_SUSPEND_RET_DEFAULT &&
+	    state < SBI_HSM_SUSPEND_RET_PLATFORM)
+		return false;
+
+	if (state > SBI_HSM_SUSPEND_NON_RET_DEFAULT &&
+	    state < SBI_HSM_SUSPEND_NON_RET_PLATFORM)
+		return false;
+
+	return true;
+}
+
+bool riscv_sbi_hsm_is_supported(void)
+{
+	/*
+	 * The SBI HSM suspend function is only available when:
+	 * 1) SBI version is 0.3 or higher
+	 * 2) SBI HSM extension is available
+	 */
+	if (sbi_spec_version < sbi_mk_version(0, 3) ||
+	    !sbi_probe_extension(SBI_EXT_HSM)) {
+		pr_info("HSM suspend not available\n");
+		return false;
+	}
+
+	return true;
+}
 #endif /* CONFIG_RISCV_SBI */

drivers/cpuidle/cpuidle-riscv-sbi.c

@@ -73,36 +73,16 @@ static inline bool sbi_is_domain_state_available(void)
 	return data->available;
 }
 
-static int sbi_suspend_finisher(unsigned long suspend_type,
-				unsigned long resume_addr,
-				unsigned long opaque)
-{
-	struct sbiret ret;
-
-	ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_SUSPEND,
-			suspend_type, resume_addr, opaque, 0, 0, 0);
-
-	return (ret.error) ? sbi_err_map_linux_errno(ret.error) : 0;
-}
-
-static int sbi_suspend(u32 state)
-{
-	if (state & SBI_HSM_SUSP_NON_RET_BIT)
-		return cpu_suspend(state, sbi_suspend_finisher);
-	else
-		return sbi_suspend_finisher(state, 0, 0);
-}
-
 static __cpuidle int sbi_cpuidle_enter_state(struct cpuidle_device *dev,
 					     struct cpuidle_driver *drv, int idx)
 {
 	u32 *states = __this_cpu_read(sbi_cpuidle_data.states);
 	u32 state = states[idx];
 
 	if (state & SBI_HSM_SUSP_NON_RET_BIT)
-		return CPU_PM_CPU_IDLE_ENTER_PARAM(sbi_suspend, idx, state);
+		return CPU_PM_CPU_IDLE_ENTER_PARAM(riscv_sbi_hart_suspend, idx, state);
 	else
-		return CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM(sbi_suspend,
+		return CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM(riscv_sbi_hart_suspend,
 							     idx, state);
 }
 
@@ -133,7 +113,7 @@ static __cpuidle int __sbi_enter_domain_idle_state(struct cpuidle_device *dev,
 	else
 		state = states[idx];
 
-	ret = sbi_suspend(state) ? -1 : idx;
+	ret = riscv_sbi_hart_suspend(state) ? -1 : idx;
 
 	ct_cpuidle_exit();
 
@@ -206,17 +186,6 @@ static const struct of_device_id sbi_cpuidle_state_match[] = {
 	{ },
 };
 
-static bool sbi_suspend_state_is_valid(u32 state)
-{
-	if (state > SBI_HSM_SUSPEND_RET_DEFAULT &&
-	    state < SBI_HSM_SUSPEND_RET_PLATFORM)
-		return false;
-	if (state > SBI_HSM_SUSPEND_NON_RET_DEFAULT &&
-	    state < SBI_HSM_SUSPEND_NON_RET_PLATFORM)
-		return false;
-	return true;
-}
-
 static int sbi_dt_parse_state_node(struct device_node *np, u32 *state)
 {
 	int err = of_property_read_u32(np, "riscv,sbi-suspend-param", state);
@@ -226,7 +195,7 @@ static int sbi_dt_parse_state_node(struct device_node *np, u32 *state)
 		return err;
 	}
 
-	if (!sbi_suspend_state_is_valid(*state)) {
+	if (!riscv_sbi_suspend_state_is_valid(*state)) {
 		pr_warn("Invalid SBI suspend state %#x\n", *state);
 		return -EINVAL;
 	}
@@ -607,16 +576,8 @@ static int __init sbi_cpuidle_init(void)
 	int ret;
 	struct platform_device *pdev;
 
-	/*
-	 * The SBI HSM suspend function is only available when:
-	 * 1) SBI version is 0.3 or higher
-	 * 2) SBI HSM extension is available
-	 */
-	if ((sbi_spec_version < sbi_mk_version(0, 3)) ||
-	    !sbi_probe_extension(SBI_EXT_HSM)) {
-		pr_info("HSM suspend not available\n");
+	if (!riscv_sbi_hsm_is_supported())
 		return 0;
-	}
 
 	ret = platform_driver_register(&sbi_cpuidle_driver);
 	if (ret)