[PATCH v4 12/19] cpufreq/amd-pstate: Replace all AMD_CPPC_* macros with masks

Mario Limonciello
2025-02-19T21:03:28Z

Bitfield masks are easier to follow and less error prone.

Reviewed-by: Dhananjay Ugwekar <dhananjay.ugwekar@amd.com>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
v3:
* Add tag
* Add missing includes
v2:
* Add a comment in msr-index.h
* Pick up tag
---
arch/x86/include/asm/msr-index.h | 20 +++++++++++---------
arch/x86/kernel/acpi/cppc.c | 4 +++-
drivers/cpufreq/amd-pstate-ut.c | 9 +++++----
drivers/cpufreq/amd-pstate.c | 16 ++++++----------
4 files changed, 25 insertions(+), 24 deletions(-)

diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index c84930610c7e6..cfcc49e5cf925 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -701,15 +701,17 @@
#define MSR_AMD_CPPC_REQ 0xc00102b3
#define MSR_AMD_CPPC_STATUS 0xc00102b4

-#define AMD_CPPC_LOWEST_PERF(x) (((x) >> 0) & 0xff)
-#define AMD_CPPC_LOWNONLIN_PERF(x) (((x) >> 8) & 0xff)
-#define AMD_CPPC_NOMINAL_PERF(x) (((x) >> 16) & 0xff)
-#define AMD_CPPC_HIGHEST_PERF(x) (((x) >> 24) & 0xff)
-
-#define AMD_CPPC_MAX_PERF(x) (((x) & 0xff) << 0)
-#define AMD_CPPC_MIN_PERF(x) (((x) & 0xff) << 8)
-#define AMD_CPPC_DES_PERF(x) (((x) & 0xff) << 16)
-#define AMD_CPPC_ENERGY_PERF_PREF(x) (((x) & 0xff) << 24)
+/* Masks for use with MSR_AMD_CPPC_CAP1 */
+#define AMD_CPPC_LOWEST_PERF_MASK GENMASK(7, 0)
+#define AMD_CPPC_LOWNONLIN_PERF_MASK GENMASK(15, 8)
+#define AMD_CPPC_NOMINAL_PERF_MASK GENMASK(23, 16)
+#define AMD_CPPC_HIGHEST_PERF_MASK GENMASK(31, 24)
+
+/* Masks for use with MSR_AMD_CPPC_REQ */
+#define AMD_CPPC_MAX_PERF_MASK GENMASK(7, 0)
+#define AMD_CPPC_MIN_PERF_MASK GENMASK(15, 8)
+#define AMD_CPPC_DES_PERF_MASK GENMASK(23, 16)
+#define AMD_CPPC_EPP_PERF_MASK GENMASK(31, 24)

/* AMD Performance Counter Global Status and Control MSRs */
#define MSR_AMD64_PERF_CNTR_GLOBAL_STATUS 0xc0000300
diff --git a/arch/x86/kernel/acpi/cppc.c b/arch/x86/kernel/acpi/cppc.c
index d745dd586303c..77bfb846490c0 100644
--- a/arch/x86/kernel/acpi/cppc.c
+++ b/arch/x86/kernel/acpi/cppc.c
@@ -4,6 +4,8 @@
* Copyright (c) 2016, Intel Corporation.
*/

+#include <linux/bitfield.h>
+
#include <acpi/cppc_acpi.h>
#include <asm/msr.h>
#include <asm/processor.h>
@@ -149,7 +151,7 @@ int amd_get_highest_perf(unsigned int cpu, u32 *highest_perf)
if (ret)
goto out;

- val = AMD_CPPC_HIGHEST_PERF(val);
+ val = FIELD_GET(AMD_CPPC_HIGHEST_PERF_MASK, val);
} else {
ret = cppc_get_highest_perf(cpu, &val);
if (ret)
diff --git a/drivers/cpufreq/amd-pstate-ut.c b/drivers/cpufreq/amd-pstate-ut.c
index 6b04b5b54b3b5..9a2de25a4b749 100644
--- a/drivers/cpufreq/amd-pstate-ut.c
+++ b/drivers/cpufreq/amd-pstate-ut.c
@@ -22,6 +22,7 @@

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

+#include <linux/bitfield.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
@@ -142,10 +143,10 @@ static int amd_pstate_ut_check_perf(u32 index)
return ret;
}

- highest_perf = AMD_CPPC_HIGHEST_PERF(cap1);
- nominal_perf = AMD_CPPC_NOMINAL_PERF(cap1);
- lowest_nonlinear_perf = AMD_CPPC_LOWNONLIN_PERF(cap1);
- lowest_perf = AMD_CPPC_LOWEST_PERF(cap1);
+ highest_perf = FIELD_GET(AMD_CPPC_HIGHEST_PERF_MASK, cap1);
+ nominal_perf = FIELD_GET(AMD_CPPC_NOMINAL_PERF_MASK, cap1);
+ lowest_nonlinear_perf = FIELD_GET(AMD_CPPC_LOWNONLIN_PERF_MASK, cap1);
+ lowest_perf = FIELD_GET(AMD_CPPC_LOWEST_PERF_MASK, cap1);
}

cur_perf = READ_ONCE(cpudata->perf);
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index e61a430183693..cd4048908acf8 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -89,11 +89,6 @@ static bool cppc_enabled;
static bool amd_pstate_prefcore = true;
static struct quirk_entry *quirks;

-#define AMD_CPPC_MAX_PERF_MASK GENMASK(7, 0)
-#define AMD_CPPC_MIN_PERF_MASK GENMASK(15, 8)
-#define AMD_CPPC_DES_PERF_MASK GENMASK(23, 16)
-#define AMD_CPPC_EPP_PERF_MASK GENMASK(31, 24)
-
/*
* AMD Energy Preference Performance (EPP)
* The EPP is used in the CCLK DPM controller to drive
@@ -439,12 +434,13 @@ static int msr_init_perf(struct amd_cpudata *cpudata)

perf.highest_perf = numerator;
perf.max_limit_perf = numerator;
- perf.min_limit_perf = AMD_CPPC_LOWEST_PERF(cap1);
- perf.nominal_perf = AMD_CPPC_NOMINAL_PERF(cap1);
- perf.lowest_nonlinear_perf = AMD_CPPC_LOWNONLIN_PERF(cap1);
- perf.lowest_perf = AMD_CPPC_LOWEST_PERF(cap1);
+ perf.min_limit_perf = FIELD_GET(AMD_CPPC_LOWEST_PERF_MASK, cap1);
+ perf.nominal_perf = FIELD_GET(AMD_CPPC_NOMINAL_PERF_MASK, cap1);
+ perf.lowest_nonlinear_perf = FIELD_GET(AMD_CPPC_LOWNONLIN_PERF_MASK, cap1);
+ perf.lowest_perf = FIELD_GET(AMD_CPPC_LOWEST_PERF_MASK, cap1);
WRITE_ONCE(cpudata->perf, perf);
- WRITE_ONCE(cpudata->prefcore_ranking, AMD_CPPC_HIGHEST_PERF(cap1));
+ WRITE_ONCE(cpudata->prefcore_ranking, FIELD_GET(AMD_CPPC_HIGHEST_PERF_MASK, cap1));
+
return 0;
}

--
2.43.0