[Intel-gfx] [PATCH v5] drm/i915/debugfs : PCU PM_REQ and PM_RES registers

[Saichandana S]

This debugfs provides the display PM debug information like Time
to Next VBI and Time to Next Fill from Display Engine <-> PCU Mailbox.

V2:
Added a functional print to debugfs. [Jani Nikula]

V3:
Used separate variables to store the register values and also
used REG_GENMASK and REG_BIT for mask preparation. [Anshuman Gupta]

Removed reading of register contents. Replaced local variable with yesno().
Placed register macros separately, distinguishing from other
macros. [Jani Nikula]

V4 : Used i915 as local variable. [Anshuman Gupta, Jani Nikula]

V5 : Added wakeref to wakeup device. [Chris Wilson]
Signed-off-by: Saichandana S <saichandana.s at intel.com>
---
 .../drm/i915/display/intel_display_debugfs.c  | 24 +++++++++++++++++++
 drivers/gpu/drm/i915/i915_reg.h               |  9 +++++++
 2 files changed, 33 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_display_debugfs.c b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
index d6e4a9237bda..29aaa41fdeec 100644
--- a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
+++ b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
@@ -591,6 +591,29 @@ static int i915_dmc_info(struct seq_file *m, void *unused)
 	return 0;
 }
 
+static int i915_pcu_pm_req_res_info(struct seq_file *m, void *unused)
+{
+	struct drm_i915_private *i915 = node_to_i915(m->private);
+	struct intel_csr *csr = &i915->csr;
+	intel_wakeref_t wakeref;
+
+	if (!HAS_CSR(i915))
+		return -ENODEV;
+
+	wakeref = intel_runtime_pm_get(&i915->runtime_pm);
+	if (!csr->dmc_payload)
+		return 0;
+	seq_printf(m, "Time to Next Fill : 0x%08x\n",
+		   intel_de_read(i915, PM_RSP_DBG_0) & PM_RESP_TTNF_MASK);
+	seq_printf(m, "Time to Next VBI : 0x%08x\n",
+		   (intel_de_read(i915, PM_RSP_DBG_0) & PM_RESP_TTNVBI_MASK) >> 16);
+	seq_printf(m, "Selective Exit Latency : 0x%08x\n",
+		   intel_de_read(i915, PM_RSP_DBG_1) & PM_RESP_SEL_EXIT_LATENCY_MASK);
+
+	intel_runtime_pm_put(&i915->runtime_pm, wakeref);
+	return 0;
+}
+
 static void intel_seq_print_mode(struct seq_file *m, int tabs,
 				 const struct drm_display_mode *mode)
 {
@@ -2128,6 +2151,7 @@ static const struct drm_info_list intel_display_debugfs_list[] = {
 	{"i915_edp_psr_status", i915_edp_psr_status, 0},
 	{"i915_power_domain_info", i915_power_domain_info, 0},
 	{"i915_dmc_info", i915_dmc_info, 0},
+	{"i915_pcu_pm_req_res_info", i915_pcu_pm_req_res_info, 0},
 	{"i915_display_info", i915_display_info, 0},
 	{"i915_shared_dplls_info", i915_shared_dplls_info, 0},
 	{"i915_dp_mst_info", i915_dp_mst_info, 0},
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 224ad897af34..93d319bf80fd 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -12525,4 +12525,13 @@ enum skl_power_gate {
 #define TGL_ROOT_DEVICE_SKU_ULX		0x2
 #define TGL_ROOT_DEVICE_SKU_ULT		0x4
 
+/*These registers are of functional registers for PM debug request and response registers*/
+#define PM_REQ_DBG_0				_MMIO(0x45284)
+#define PM_REQ_DBG_1				_MMIO(0x45288)
+#define PM_RSP_DBG_0				_MMIO(0x4528C)
+#define   PM_RESP_TTNF_MASK			REG_GENMASK(15, 0)
+#define   PM_RESP_TTNVBI_MASK			REG_GENMASK(31, 16)
+#define PM_RSP_DBG_1				_MMIO(0x45290)
+#define   PM_RESP_SEL_EXIT_LATENCY_MASK		REG_GENMASK(2, 0)
+
 #endif /* _I915_REG_H_ */
-- 
2.30.0