Merge: platform/x86/intel/pmc: Disable C1 auto-demotion during suspend - blocks s0ix

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-10/-/merge_requests/126

Description:
updates for platform/x86/intel/pmc: to disable C1 auto-demotion during suspend - blocks s0ix

JIRA: https://issues.redhat.com/browse/RHEL-66570

Build Info: https://brewweb.engineering.redhat.com/brew/taskinfo?taskID=66317330

Tested: Successful platform test results on Intel (intel-meteorlake-p-h-01) system.

Signed-off-by: Steve Best <sbest@redhat.com>

Approved-by: Tony Camuso <tcamuso@redhat.com>
Approved-by: David Arcari <darcari@redhat.com>
Approved-by: CKI KWF Bot <cki-ci-bot+kwf-gitlab-com@redhat.com>

Merged-by: Jan Stancek <jstancek@redhat.com>

Author: jstancek

drivers/platform/x86/intel/pmc/arl.c

@@ -687,9 +687,8 @@ static void arl_d3_fixup(void)
 static int arl_resume(struct pmc_dev *pmcdev)
 {
 	arl_d3_fixup();
-	pmc_core_send_ltr_ignore(pmcdev, 3, 0);
 
-	return pmc_core_resume_common(pmcdev);
+	return cnl_resume(pmcdev);
 }
 
 int arl_core_init(struct pmc_dev *pmcdev)

drivers/platform/x86/intel/pmc/cnp.c

@@ -8,6 +8,8 @@
  *
  */
 
+#include <linux/smp.h>
+#include <linux/suspend.h>
 #include "core.h"
 
 /* Cannon Lake: PGD PFET Enable Ack Status Register(s) bitmap */
@@ -204,8 +206,57 @@ const struct pmc_reg_map cnp_reg_map = {
 	.etr3_offset = ETR3_OFFSET,
 };
 
+
+/*
+ * Disable C1 auto-demotion
+ *
+ * Aggressive C1 auto-demotion may lead to failure to enter the deepest C-state
+ * during suspend-to-idle, causing high power consumption. To prevent this, we
+ * disable C1 auto-demotion during suspend and re-enable on resume.
+ *
+ * Note that, although MSR_PKG_CST_CONFIG_CONTROL has 'package' in its name, it
+ * is actually a per-core MSR on client platforms, affecting only a single CPU.
+ * Therefore, it must be configured on all online CPUs. The online cpu mask is
+ * unchanged during the phase of suspend/resume as user space is frozen.
+ */
+
+static DEFINE_PER_CPU(u64, pkg_cst_config);
+
+static void disable_c1_auto_demote(void *unused)
+{
+	int cpunum = smp_processor_id();
+	u64 val;
+
+	rdmsrl(MSR_PKG_CST_CONFIG_CONTROL, val);
+	per_cpu(pkg_cst_config, cpunum) = val;
+	val &= ~NHM_C1_AUTO_DEMOTE;
+	wrmsrl(MSR_PKG_CST_CONFIG_CONTROL, val);
+
+	pr_debug("%s: cpu:%d cst %llx\n", __func__, cpunum, val);
+}
+
+static void restore_c1_auto_demote(void *unused)
+{
+	int cpunum = smp_processor_id();
+
+	wrmsrl(MSR_PKG_CST_CONFIG_CONTROL, per_cpu(pkg_cst_config, cpunum));
+
+	pr_debug("%s: cpu:%d cst %llx\n", __func__, cpunum,
+		 per_cpu(pkg_cst_config, cpunum));
+}
+
+static void s2idle_cpu_quirk(smp_call_func_t func)
+{
+	if (pm_suspend_via_firmware())
+		return;
+
+	on_each_cpu(func, NULL, true);
+}
+
 void cnl_suspend(struct pmc_dev *pmcdev)
 {
+	s2idle_cpu_quirk(disable_c1_auto_demote);
+
 	/*
 	 * Due to a hardware limitation, the GBE LTR blocks PC10
 	 * when a cable is attached. To unblock PC10 during suspend,
@@ -216,6 +267,8 @@ void cnl_suspend(struct pmc_dev *pmcdev)
 
 int cnl_resume(struct pmc_dev *pmcdev)
 {
+	s2idle_cpu_quirk(restore_c1_auto_demote);
+
 	pmc_core_send_ltr_ignore(pmcdev, 3, 0);
 
 	return pmc_core_resume_common(pmcdev);

drivers/platform/x86/intel/pmc/lnl.c

@@ -546,9 +546,8 @@ static void lnl_d3_fixup(void)
 static int lnl_resume(struct pmc_dev *pmcdev)
 {
 	lnl_d3_fixup();
-	pmc_core_send_ltr_ignore(pmcdev, 3, 0);
 
-	return pmc_core_resume_common(pmcdev);
+	return cnl_resume(pmcdev);
 }
 
 int lnl_core_init(struct pmc_dev *pmcdev)

drivers/platform/x86/intel/pmc/mtl.c

@@ -986,9 +986,8 @@ static void mtl_d3_fixup(void)
 static int mtl_resume(struct pmc_dev *pmcdev)
 {
 	mtl_d3_fixup();
-	pmc_core_send_ltr_ignore(pmcdev, 3, 0);
 
-	return pmc_core_resume_common(pmcdev);
+	return cnl_resume(pmcdev);
 }
 
 int mtl_core_init(struct pmc_dev *pmcdev)