platform/x86: intel_pmc_core: Add debugfs entry to access sub-state residencies

Prior to Tiger Lake, the platforms that support pmc_core have no
sub-states of S0ix. Tiger Lake has 8 sub-states/low power modes of S0ix
ranging from S0i2.0-S0i2.2 and S0i3.0-S0i3.4, simply represented as
S0ix.y.

Create a debugfs entry to access residency of each sub-state.

Cc: Srinivas Pandruvada <srinivas.pandruvada@intel.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: David Box <david.e.box@intel.com>
Signed-off-by: David Box <david.e.box@intel.com>
Signed-off-by: Gayatri Kammela <gayatri.kammela@intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

drivers/platform/x86/intel_pmc_core.c

@@ -422,6 +422,8 @@ static const struct pmc_reg_map tgl_reg_map = {
 	.pm_cfg_offset = CNP_PMC_PM_CFG_OFFSET,
 	.pm_read_disable_bit = CNP_PMC_READ_DISABLE_BIT,
 	.ltr_ignore_max = TGL_NUM_IP_IGN_ALLOWED,
+	.lpm_en_offset = TGL_LPM_EN_OFFSET,
+	.lpm_residency_offset = TGL_LPM_RESIDENCY_OFFSET,
 };
 
 static inline u32 pmc_core_reg_read(struct pmc_dev *pmcdev, int reg_offset)
@@ -794,6 +796,26 @@ static int pmc_core_ltr_show(struct seq_file *s, void *unused)
 }
 DEFINE_SHOW_ATTRIBUTE(pmc_core_ltr);
 
+static int pmc_core_substate_res_show(struct seq_file *s, void *unused)
+{
+	struct pmc_dev *pmcdev = s->private;
+	u32 offset = pmcdev->map->lpm_residency_offset;
+	u32 lpm_en;
+	int index;
+
+	lpm_en = pmc_core_reg_read(pmcdev, pmcdev->map->lpm_en_offset);
+	seq_printf(s, "status substate residency\n");
+	for (index = 0; lpm_modes[index]; index++) {
+		seq_printf(s, "%7s %7s %-15u\n",
+			   BIT(index) & lpm_en ? "Enabled" : " ",
+			   lpm_modes[index], pmc_core_reg_read(pmcdev, offset));
+		offset += 4;
+	}
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(pmc_core_substate_res);
+
 static int pmc_core_pkgc_show(struct seq_file *s, void *unused)
 {
 	struct pmc_dev *pmcdev = s->private;
@@ -859,6 +881,12 @@ static void pmc_core_dbgfs_register(struct pmc_dev *pmcdev)
 		debugfs_create_bool("slp_s0_dbg_latch", 0644,
 				    dir, &slps0_dbg_latch);
 	}
+
+	if (pmcdev->map->lpm_en_offset) {
+		debugfs_create_file("substate_residencies", 0444,
+				    pmcdev->dbgfs_dir, pmcdev,
+				    &pmc_core_substate_res_fops);
+	}
 }
 #else
 static inline void pmc_core_dbgfs_register(struct pmc_dev *pmcdev)

drivers/platform/x86/intel_pmc_core.h

@@ -188,6 +188,24 @@ enum ppfear_regs {
 
 #define TGL_NUM_IP_IGN_ALLOWED			22
 
+/*
+ * Tigerlake Power Management Controller register offsets
+ */
+#define TGL_LPM_EN_OFFSET			0x1C78
+#define TGL_LPM_RESIDENCY_OFFSET		0x1C80
+
+const char *lpm_modes[] = {
+	"S0i2.0",
+	"S0i2.1",
+	"S0i2.2",
+	"S0i3.0",
+	"S0i3.1",
+	"S0i3.2",
+	"S0i3.3",
+	"S0i3.4",
+	NULL
+};
+
 struct pmc_bit_map {
 	const char *name;
 	u32 bit_mask;
@@ -231,6 +249,9 @@ struct pmc_reg_map {
 	const u32 slps0_dbg_offset;
 	const u32 ltr_ignore_max;
 	const u32 pm_vric1_offset;
+	/* Low Power Mode registers */
+	const u32 lpm_en_offset;
+	const u32 lpm_residency_offset;
 };
 
 /**