intel_idle: Add AlderLake support

Similar to SPR, the C1 and C1E states on ADL are mutually exclusive.
Only one of them can be enabled at a time.

But contrast to SPR, which usually has a strong latency requirement
as a Xeon processor, C1E is preferred on ADL for better energy
efficiency.

Add custom C-state tables for ADL with both C1 and C1E, and

 1. Enable the "C1E promotion" bit in MSR_IA32_POWER_CTL and mark C1
    with the CPUIDLE_FLAG_UNUSABLE flag, so C1 is not available by
    default.

 2. Add support for the "preferred_cstates" module parameter, so that
    users can choose to use C1 instead of C1E by booting with
    "intel_idle.preferred_cstates=2".

Separate custom C-state tables are introduced for the ADL mobile and
desktop processors, because of the exit latency differences between
these two variants, especially with respect to PC10.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
[ rjw: Changelog edits, code rearrangement ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 133 insertions, 0 deletions

diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
index 47551ab73ca8..b9bb94bd0f67 100644
--- a/drivers/idle/intel_idle.c
+++ b/drivers/idle/intel_idle.c
@@ -765,6 +765,106 @@ static struct cpuidle_state icx_cstates[] __initdata = {
 };
 
 /*
+ * On AlderLake C1 has to be disabled if C1E is enabled, and vice versa.
+ * C1E is enabled only if "C1E promotion" bit is set in MSR_IA32_POWER_CTL.
+ * But in this case there is effectively no C1, because C1 requests are
+ * promoted to C1E. If the "C1E promotion" bit is cleared, then both C1
+ * and C1E requests end up with C1, so there is effectively no C1E.
+ *
+ * By default we enable C1E and disable C1 by marking it with
+ * 'CPUIDLE_FLAG_UNUSABLE'.
+ */
+static struct cpuidle_state adl_cstates[] __initdata = {
+	{
+		.name = "C1",
+		.desc = "MWAIT 0x00",
+		.flags = MWAIT2flg(0x00) | CPUIDLE_FLAG_UNUSABLE,
+		.exit_latency = 1,
+		.target_residency = 1,
+		.enter = &intel_idle,
+		.enter_s2idle = intel_idle_s2idle, },
+	{
+		.name = "C1E",
+		.desc = "MWAIT 0x01",
+		.flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_ALWAYS_ENABLE,
+		.exit_latency = 2,
+		.target_residency = 4,
+		.enter = &intel_idle,
+		.enter_s2idle = intel_idle_s2idle, },
+	{
+		.name = "C6",
+		.desc = "MWAIT 0x20",
+		.flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
+		.exit_latency = 220,
+		.target_residency = 600,
+		.enter = &intel_idle,
+		.enter_s2idle = intel_idle_s2idle, },
+	{
+		.name = "C8",
+		.desc = "MWAIT 0x40",
+		.flags = MWAIT2flg(0x40) | CPUIDLE_FLAG_TLB_FLUSHED,
+		.exit_latency = 280,
+		.target_residency = 800,
+		.enter = &intel_idle,
+		.enter_s2idle = intel_idle_s2idle, },
+	{
+		.name = "C10",
+		.desc = "MWAIT 0x60",
+		.flags = MWAIT2flg(0x60) | CPUIDLE_FLAG_TLB_FLUSHED,
+		.exit_latency = 680,
+		.target_residency = 2000,
+		.enter = &intel_idle,
+		.enter_s2idle = intel_idle_s2idle, },
+	{
+		.enter = NULL }
+};
+
+static struct cpuidle_state adl_l_cstates[] __initdata = {
+	{
+		.name = "C1",
+		.desc = "MWAIT 0x00",
+		.flags = MWAIT2flg(0x00) | CPUIDLE_FLAG_UNUSABLE,
+		.exit_latency = 1,
+		.target_residency = 1,
+		.enter = &intel_idle,
+		.enter_s2idle = intel_idle_s2idle, },
+	{
+		.name = "C1E",
+		.desc = "MWAIT 0x01",
+		.flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_ALWAYS_ENABLE,
+		.exit_latency = 2,
+		.target_residency = 4,
+		.enter = &intel_idle,
+		.enter_s2idle = intel_idle_s2idle, },
+	{
+		.name = "C6",
+		.desc = "MWAIT 0x20",
+		.flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
+		.exit_latency = 170,
+		.target_residency = 500,
+		.enter = &intel_idle,
+		.enter_s2idle = intel_idle_s2idle, },
+	{
+		.name = "C8",
+		.desc = "MWAIT 0x40",
+		.flags = MWAIT2flg(0x40) | CPUIDLE_FLAG_TLB_FLUSHED,
+		.exit_latency = 200,
+		.target_residency = 600,
+		.enter = &intel_idle,
+		.enter_s2idle = intel_idle_s2idle, },
+	{
+		.name = "C10",
+		.desc = "MWAIT 0x60",
+		.flags = MWAIT2flg(0x60) | CPUIDLE_FLAG_TLB_FLUSHED,
+		.exit_latency = 230,
+		.target_residency = 700,
+		.enter = &intel_idle,
+		.enter_s2idle = intel_idle_s2idle, },
+	{
+		.enter = NULL }
+};
+
+/*
  * On Sapphire Rapids Xeon C1 has to be disabled if C1E is enabled, and vice
  * versa. On SPR C1E is enabled only if "C1E promotion" bit is set in
  * MSR_IA32_POWER_CTL. But in this case there effectively no C1, because C1
@@ -1147,6 +1247,14 @@ static const struct idle_cpu idle_cpu_icx __initconst = {
 	.use_acpi = true,
 };
 
+static const struct idle_cpu idle_cpu_adl __initconst = {
+	.state_table = adl_cstates,
+};
+
+static const struct idle_cpu idle_cpu_adl_l __initconst = {
+	.state_table = adl_l_cstates,
+};
+
 static const struct idle_cpu idle_cpu_spr __initconst = {
 	.state_table = spr_cstates,
 	.disable_promotion_to_c1e = true,
@@ -1215,6 +1323,8 @@ static const struct x86_cpu_id intel_idle_ids[] __initconst = {
 	X86_MATCH_INTEL_FAM6_MODEL(SKYLAKE_X,		&idle_cpu_skx),
 	X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_X,		&idle_cpu_icx),
 	X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_D,		&idle_cpu_icx),
+	X86_MATCH_INTEL_FAM6_MODEL(ALDERLAKE,		&idle_cpu_adl),
+	X86_MATCH_INTEL_FAM6_MODEL(ALDERLAKE_L,		&idle_cpu_adl_l),
 	X86_MATCH_INTEL_FAM6_MODEL(SAPPHIRERAPIDS_X,	&idle_cpu_spr),
 	X86_MATCH_INTEL_FAM6_MODEL(XEON_PHI_KNL,	&idle_cpu_knl),
 	X86_MATCH_INTEL_FAM6_MODEL(XEON_PHI_KNM,	&idle_cpu_knl),
@@ -1574,6 +1684,25 @@ static void __init skx_idle_state_table_update(void)
 }
 
 /**
+ * adl_idle_state_table_update - Adjust AlderLake idle states table.
+ */
+static void __init adl_idle_state_table_update(void)
+{
+	/* Check if user prefers C1 over C1E. */
+	if (preferred_states_mask & BIT(1) && !(preferred_states_mask & BIT(2))) {
+		cpuidle_state_table[0].flags &= ~CPUIDLE_FLAG_UNUSABLE;
+		cpuidle_state_table[1].flags |= CPUIDLE_FLAG_UNUSABLE;
+
+		/* Disable C1E by clearing the "C1E promotion" bit. */
+		c1e_promotion = C1E_PROMOTION_DISABLE;
+		return;
+	}
+
+	/* Make sure C1E is enabled by default */
+	c1e_promotion = C1E_PROMOTION_ENABLE;
+}
+
+/**
  * spr_idle_state_table_update - Adjust Sapphire Rapids idle states table.
  */
 static void __init spr_idle_state_table_update(void)
@@ -1642,6 +1771,10 @@ static void __init intel_idle_init_cstates_icpu(struct cpuidle_driver *drv)
 	case INTEL_FAM6_SAPPHIRERAPIDS_X:
 		spr_idle_state_table_update();
 		break;
+	case INTEL_FAM6_ALDERLAKE:
+	case INTEL_FAM6_ALDERLAKE_L:
+		adl_idle_state_table_update();
+		break;
 	}
 
 	for (cstate = 0; cstate < CPUIDLE_STATE_MAX; ++cstate) {