diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/acpi/Makefile | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/acpi/cppc_msr.c | 58 |
2 files changed, 59 insertions, 0 deletions
diff --git a/arch/x86/kernel/acpi/Makefile b/arch/x86/kernel/acpi/Makefile index 3242e591fa82..26b78d86f25a 100644 --- a/arch/x86/kernel/acpi/Makefile +++ b/arch/x86/kernel/acpi/Makefile @@ -1,6 +1,7 @@ obj-$(CONFIG_ACPI) += boot.o obj-$(CONFIG_ACPI_SLEEP) += sleep.o wakeup_$(BITS).o obj-$(CONFIG_ACPI_APEI) += apei.o +obj-$(CONFIG_ACPI_CPPC_LIB) += cppc_msr.o ifneq ($(CONFIG_ACPI_PROCESSOR),) obj-y += cstate.o diff --git a/arch/x86/kernel/acpi/cppc_msr.c b/arch/x86/kernel/acpi/cppc_msr.c new file mode 100644 index 000000000000..6fb478bf82fd --- /dev/null +++ b/arch/x86/kernel/acpi/cppc_msr.c @@ -0,0 +1,58 @@ +/* + * cppc_msr.c: MSR Interface for CPPC + * Copyright (c) 2016, Intel Corporation. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + */ + +#include <acpi/cppc_acpi.h> +#include <asm/msr.h> + +/* Refer to drivers/acpi/cppc_acpi.c for the description of functions */ + +bool cpc_ffh_supported(void) +{ + return true; +} + +int cpc_read_ffh(int cpunum, struct cpc_reg *reg, u64 *val) +{ + int err; + + err = rdmsrl_safe_on_cpu(cpunum, reg->address, val); + if (!err) { + u64 mask = GENMASK_ULL(reg->bit_offset + reg->bit_width - 1, + reg->bit_offset); + + *val &= mask; + *val >>= reg->bit_offset; + } + return err; +} + +int cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val) +{ + u64 rd_val; + int err; + + err = rdmsrl_safe_on_cpu(cpunum, reg->address, &rd_val); + if (!err) { + u64 mask = GENMASK_ULL(reg->bit_offset + reg->bit_width - 1, + reg->bit_offset); + + val <<= reg->bit_offset; + val &= mask; + rd_val &= ~mask; + rd_val |= val; + err = wrmsrl_safe_on_cpu(cpunum, reg->address, rd_val); + } + return err; +} |