linux_dsm_epyc7002/arch/x86/kernel/acpi/cppc_msr.c
Srinivas Pandruvada a6cbcdd5ab ACPI / CPPC: Add support for functional fixed hardware address
The CPPC registers can also be accessed via functional fixed hardware
addresse(FFH) in X86. Add support by modifying cpc_read and cpc_write to
be able to read/write MSRs on x86 platform on per cpu basis.
Also with this change, acpi_cppc_processor_probe doesn't bail out if
address space id is not equal to PCC or memory address space and FFH
is supported on the system.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-09-08 23:02:14 +02:00

59 lines
1.4 KiB
C

/*
* 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;
}