intel_idle: Add constants for MSR_PKG_CST_CONFIG_CONTROL

Add two constants for the package C-state limit fields in
MSR_PKG_CST_CONFIG_CONTROL.

The SKX_ prefix stands for "Skylake Xeon" and makes it explicit that
the mask is CPU model-specific. The same values have applied to all
Xeon platforms starting from SKX.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Link: https://patch.msgid.link/20260425072532.358365-2-dedekind1@gmail.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
index f49354e3777779597c0bab38bd0d0de3ed6a09fa..259013c246d904659cc4f55291f860e24541d1aa 100644 (file)
--- a/drivers/idle/intel_idle.c
+++ b/drivers/idle/intel_idle.c
@@ -81,6 +81,11 @@ static bool ibrs_off __read_mostly;
 /* Maximum allowed C-state target residency */
 #define MAX_CMDLINE_RESIDENCY_US (100 * USEC_PER_MSEC)
 
+/* The Package C-State Limit bits in MSR_PKG_CST_CONFIG_CONTROL */
+#define SKX_PKG_CST_LIMIT_MASK GENMASK(2, 0)
+/* PC6 is enabled when Package C-State Limit >= this value */
+#define SKX_PKG_CST_LIMIT_PC6 2
+
 static char cmdline_table_str[MAX_CMDLINE_TABLE_LEN] __read_mostly;
 
 static struct cpuidle_device __percpu *intel_idle_cpuidle_devices;
@@ -2090,7 +2095,7 @@ static void __init skx_idle_state_table_update(void)
         * 011b: C6 (retention)
         * 111b: No Package C state limits.
         */
-       if ((msr & 0x7) < 2) {
+       if ((msr & SKX_PKG_CST_LIMIT_MASK) < SKX_PKG_CST_LIMIT_PC6) {
                /*
                 * Uses the CC6 + PC0 latency and 3 times of
                 * latency for target_residency if the PC6
@@ -2118,7 +2123,7 @@ static void __init spr_idle_state_table_update(void)
        rdmsrq(MSR_PKG_CST_CONFIG_CONTROL, msr);
 
        /* Limit value 2 and above allow for PC6. */
-       if ((msr & 0x7) < 2) {
+       if ((msr & SKX_PKG_CST_LIMIT_MASK) < SKX_PKG_CST_LIMIT_PC6) {
                spr_cstates[2].exit_latency = 190;
                spr_cstates[2].target_residency = 600;
        }