[Intel-gfx] [PATCH v3] drm/i915/debugfs : PM_REQ and PM_RES registers

[Saichandana S]

PM_REQ register provides the value of the last PM request from PCU to
Display Engine. PM_RES register provides the value of the last PM
response from Display Engine to PCU.
This debugfs will be used by DC9 IGT test to know about "DC9 Ready"
status.
B.Spec : 49501, 49502

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]

Signed-off-by: Saichandana S <saichandana.s at intel.com>
---
 .../drm/i915/display/intel_display_debugfs.c  | 23 +++++++++++++++++++
 drivers/gpu/drm/i915/i915_reg.h               | 10 ++++++++
 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 cd7e5519ee7d..e5997debb8e5 100644
--- a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
+++ b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
@@ -559,6 +559,28 @@ static int i915_dmc_info(struct seq_file *m, void *unused)
 	return 0;
 }
 
+static int i915_pm_req_res_info(struct seq_file *m, void *unused)
+{
+	struct drm_i915_private *dev_priv = node_to_i915(m->private);
+	struct intel_csr *csr = &dev_priv->csr;
+	u32 DC9_status;
+
+	if (!HAS_CSR(dev_priv))
+		return -ENODEV;
+	if (!csr->dmc_payload)
+		return 0;
+	DC9_status = intel_de_read(dev_priv, PM_RSP_DBG_1) & PM_RESP_DC9_READY;
+
+	seq_printf(m, "Time to Next Fill : 0x%08x\n",
+		   intel_de_read(dev_priv, PM_RSP_DBG_0) & PM_RESP_TTNF_MASK);
+	seq_printf(m, "Time to Next VBI : 0x%08x\n",
+		   (intel_de_read(dev_priv, PM_RSP_DBG_0) & PM_RESP_TTNVBI_MASK) >> 16);
+	seq_printf(m, "Selective Exit Latency : 0x%08x\n",
+		   intel_de_read(dev_priv, PM_RSP_DBG_1) & PM_RESP_SEL_EXIT_LATENCY_MASK);
+	seq_printf(m, "DC9 Ready : %s\n", yesno(DC9_status));
+	return 0;
+}
+
 static void intel_seq_print_mode(struct seq_file *m, int tabs,
 				 const struct drm_display_mode *mode)
 {
@@ -2100,6 +2122,7 @@ 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_pm_req_res_info", i915_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 0023c023f472..8c91d598dc29 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -12423,4 +12423,14 @@ 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)
+#define   PM_RESP_DC9_READY			REG_BIT(15)
+
 #endif /* _I915_REG_H_ */
-- 
2.30.0