diff options
author | Sunil V L <sunilvl@ventanamicro.com> | 2024-01-18 11:59:29 +0530 |
---|---|---|
committer | Palmer Dabbelt <palmer@rivosinc.com> | 2024-03-19 17:51:39 -0700 |
commit | 4877fc92142f635be418d8c915eb48ef87681108 (patch) | |
tree | 5643559a92bdf56e0bb6705a3ca7ebbd3d3a0e9f /drivers/acpi/riscv/cpuidle.c | |
parent | 6649182a383c9872e9543e2e7d4981d971bf0998 (diff) |
ACPI: RISC-V: Add LPI driver
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@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/20240118062930.245937-3-sunilvl@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Diffstat (limited to 'drivers/acpi/riscv/cpuidle.c')
-rw-r--r-- | drivers/acpi/riscv/cpuidle.c | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/drivers/acpi/riscv/cpuidle.c b/drivers/acpi/riscv/cpuidle.c new file mode 100644 index 000000000000..624f9bbdb58c --- /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@ventanamicro.com> + * + */ + +#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 (!riscv_sbi_hsm_is_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 (!riscv_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(riscv_sbi_hart_suspend, + lpi->index, + state); + else + return CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM(riscv_sbi_hart_suspend, + lpi->index, + state); +} |