1// SPDX-License-Identifier: GPL-2.0-only
 2/*
 3 * cppc_msr.c:  MSR Interface for CPPC
 4 * Copyright (c) 2016, Intel Corporation.
 5 */
 6
 7#include <acpi/cppc_acpi.h>
 8#include <asm/msr.h>
 9
10/* Refer to drivers/acpi/cppc_acpi.c for the description of functions */
11
12bool cpc_ffh_supported(void)
13{
14	return true;
15}
16
17int cpc_read_ffh(int cpunum, struct cpc_reg *reg, u64 *val)
18{
19	int err;
20
21	err = rdmsrl_safe_on_cpu(cpunum, reg->address, val);
22	if (!err) {
23		u64 mask = GENMASK_ULL(reg->bit_offset + reg->bit_width - 1,
24				       reg->bit_offset);
25
26		*val &= mask;
27		*val >>= reg->bit_offset;
28	}
29	return err;
30}
31
32int cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val)
33{
34	u64 rd_val;
35	int err;
36
37	err = rdmsrl_safe_on_cpu(cpunum, reg->address, &rd_val);
38	if (!err) {
39		u64 mask = GENMASK_ULL(reg->bit_offset + reg->bit_width - 1,
40				       reg->bit_offset);
41
42		val <<= reg->bit_offset;
43		val &= mask;
44		rd_val &= ~mask;
45		rd_val |= val;
46		err = wrmsrl_safe_on_cpu(cpunum, reg->address, rd_val);
47	}
48	return err;
49}