Enable Low Power Idle (LPI) based cpuidle driver for RISC-V platforms. It depends on SBI HSM calls for idle state transitions. Signed-off-by: Sunil V L <sunilvl@xxxxxxxxxxxxxxxx> --- drivers/acpi/riscv/Makefile | 3 +- drivers/acpi/riscv/cpuidle.c | 81 ++++++++++++++++++++++++++++++++++++ 2 files changed, 83 insertions(+), 1 deletion(-) create mode 100644 drivers/acpi/riscv/cpuidle.c diff --git a/drivers/acpi/riscv/Makefile b/drivers/acpi/riscv/Makefile index 8b3b126e0b94..7309d92dd477 100644 --- a/drivers/acpi/riscv/Makefile +++ b/drivers/acpi/riscv/Makefile @@ -1,2 +1,3 @@ # SPDX-License-Identifier: GPL-2.0-only -obj-y += rhct.o +obj-y += rhct.o +obj-$(CONFIG_ACPI_PROCESSOR_IDLE) += cpuidle.o diff --git a/drivers/acpi/riscv/cpuidle.c b/drivers/acpi/riscv/cpuidle.c new file mode 100644 index 000000000000..052ec3942902 --- /dev/null +++ b/drivers/acpi/riscv/cpuidle.c @@ -0,0 +1,81 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2024, Ventana Micro Systems Inc + * Author: Sunil V L <sunilvl@xxxxxxxxxxxxxxxx> + * + */ + +#include <linux/acpi.h> +#include <acpi/processor.h> +#include <linux/cpu_pm.h> +#include <linux/cpuidle.h> +#include <linux/suspend.h> +#include <asm/cpuidle.h> +#include <asm/sbi.h> +#include <asm/suspend.h> + +#define RISCV_FFH_LPI_TYPE_MASK GENMASK_ULL(63, 60) +#define RISCV_FFH_LPI_RSVD_MASK GENMASK_ULL(59, 32) + +#define RISCV_FFH_LPI_TYPE_SBI BIT_ULL(60) + +static int acpi_cpu_init_idle(unsigned int cpu) +{ + int i; + struct acpi_lpi_state *lpi; + struct acpi_processor *pr = per_cpu(processors, cpu); + + if (unlikely(!pr || !pr->flags.has_lpi)) + return -EINVAL; + + if (!is_sbi_hsm_supported()) + return -ENODEV; + + if (pr->power.count <= 1) + return -ENODEV; + + for (i = 1; i < pr->power.count; i++) { + u32 state; + + lpi = &pr->power.lpi_states[i]; + + /* + * Validate Entry Method as per FFH spec. + * bits[63:60] should be 0x1 + * bits[59:32] should be 0x0 + * bits[31:0] represent a SBI power_state + */ + if (((lpi->address & RISCV_FFH_LPI_TYPE_MASK) != RISCV_FFH_LPI_TYPE_SBI) || + (lpi->address & RISCV_FFH_LPI_RSVD_MASK)) { + pr_warn("Invalid LPI entry method %#llx\n", lpi->address); + return -EINVAL; + } + + state = lpi->address; + if (!sbi_suspend_state_is_valid(state)) { + pr_warn("Invalid SBI power state %#x\n", state); + return -EINVAL; + } + } + + return 0; +} + +int acpi_processor_ffh_lpi_probe(unsigned int cpu) +{ + return acpi_cpu_init_idle(cpu); +} + +int acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi) +{ + u32 state = lpi->address; + + if (state & SBI_HSM_SUSP_NON_RET_BIT) + return CPU_PM_CPU_IDLE_ENTER_PARAM(sbi_suspend, + lpi->index, + state); + else + return CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM(sbi_suspend, + lpi->index, + state); +} -- 2.34.1