drm/i915: Added debugfs support for PSR Status

Adding support for PSR Status, PSR entry counter and performance counters.
Heavily based on initial work from Shobhit.

v2: Fix PSR Status Link bits by Paulo Zanoni.
v3: Prefer seq_puts to seq_printf by Paulo Zanoni.
v4: Fix identation by Paulo Zanoni.
v5: Return earlier if it isn't Haswell in order to avoid reading non-existing
    registers - by Paulo Zanoni.

CC: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Credits-by: Shobhit Kumar <shobhit.kumar@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@gmail.com>
Reviewed-by: Shobhit Kumar <shobhit.kumar@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_debugfs.c

@@ -1545,6 +1545,100 @@ static int i915_llc(struct seq_file *m, void *data)
 	return 0;
 }
 
+static int i915_edp_psr_status(struct seq_file *m, void *data)
+{
+	struct drm_info_node *node = m->private;
+	struct drm_device *dev = node->minor->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	u32 psrctl, psrstat, psrperf;
+
+	if (!IS_HASWELL(dev)) {
+		seq_puts(m, "PSR not supported on this platform\n");
+		return 0;
+	}
+
+	psrctl = I915_READ(EDP_PSR_CTL);
+	seq_printf(m, "PSR Enabled: %s\n",
+		   yesno(psrctl & EDP_PSR_ENABLE));
+
+	psrstat = I915_READ(EDP_PSR_STATUS_CTL);
+
+	seq_puts(m, "PSR Current State: ");
+	switch (psrstat & EDP_PSR_STATUS_STATE_MASK) {
+	case EDP_PSR_STATUS_STATE_IDLE:
+		seq_puts(m, "Reset state\n");
+		break;
+	case EDP_PSR_STATUS_STATE_SRDONACK:
+		seq_puts(m, "Wait for TG/Stream to send on frame of data after SRD conditions are met\n");
+		break;
+	case EDP_PSR_STATUS_STATE_SRDENT:
+		seq_puts(m, "SRD entry\n");
+		break;
+	case EDP_PSR_STATUS_STATE_BUFOFF:
+		seq_puts(m, "Wait for buffer turn off\n");
+		break;
+	case EDP_PSR_STATUS_STATE_BUFON:
+		seq_puts(m, "Wait for buffer turn on\n");
+		break;
+	case EDP_PSR_STATUS_STATE_AUXACK:
+		seq_puts(m, "Wait for AUX to acknowledge on SRD exit\n");
+		break;
+	case EDP_PSR_STATUS_STATE_SRDOFFACK:
+		seq_puts(m, "Wait for TG/Stream to acknowledge the SRD VDM exit\n");
+		break;
+	default:
+		seq_puts(m, "Unknown\n");
+		break;
+	}
+
+	seq_puts(m, "Link Status: ");
+	switch (psrstat & EDP_PSR_STATUS_LINK_MASK) {
+	case EDP_PSR_STATUS_LINK_FULL_OFF:
+		seq_puts(m, "Link is fully off\n");
+		break;
+	case EDP_PSR_STATUS_LINK_FULL_ON:
+		seq_puts(m, "Link is fully on\n");
+		break;
+	case EDP_PSR_STATUS_LINK_STANDBY:
+		seq_puts(m, "Link is in standby\n");
+		break;
+	default:
+		seq_puts(m, "Unknown\n");
+		break;
+	}
+
+	seq_printf(m, "PSR Entry Count: %u\n",
+		   psrstat >> EDP_PSR_STATUS_COUNT_SHIFT &
+		   EDP_PSR_STATUS_COUNT_MASK);
+
+	seq_printf(m, "Max Sleep Timer Counter: %u\n",
+		   psrstat >> EDP_PSR_STATUS_MAX_SLEEP_TIMER_SHIFT &
+		   EDP_PSR_STATUS_MAX_SLEEP_TIMER_MASK);
+
+	seq_printf(m, "Had AUX error: %s\n",
+		   yesno(psrstat & EDP_PSR_STATUS_AUX_ERROR));
+
+	seq_printf(m, "Sending AUX: %s\n",
+		   yesno(psrstat & EDP_PSR_STATUS_AUX_SENDING));
+
+	seq_printf(m, "Sending Idle: %s\n",
+		   yesno(psrstat & EDP_PSR_STATUS_SENDING_IDLE));
+
+	seq_printf(m, "Sending TP2 TP3: %s\n",
+		   yesno(psrstat & EDP_PSR_STATUS_SENDING_TP2_TP3));
+
+	seq_printf(m, "Sending TP1: %s\n",
+		   yesno(psrstat & EDP_PSR_STATUS_SENDING_TP1));
+
+	seq_printf(m, "Idle Count: %u\n",
+		   psrstat & EDP_PSR_STATUS_IDLE_MASK);
+
+	psrperf = (I915_READ(EDP_PSR_PERF_CNT)) & EDP_PSR_PERF_CNT_MASK;
+	seq_printf(m, "Performance Counter: %u\n", psrperf);
+
+	return 0;
+}
+
 static int
 i915_wedged_get(void *data, u64 *val)
 {
@@ -1977,6 +2071,7 @@ static struct drm_info_list i915_debugfs_list[] = {
 	{"i915_ppgtt_info", i915_ppgtt_info, 0},
 	{"i915_dpio", i915_dpio_info, 0},
 	{"i915_llc", i915_llc, 0},
+	{"i915_edp_psr_status", i915_edp_psr_status, 0},
 };
 #define I915_DEBUGFS_ENTRIES ARRAY_SIZE(i915_debugfs_list)
 

drivers/gpu/drm/i915/i915_reg.h

@@ -1814,6 +1814,30 @@
 
 #define EDP_PSR_STATUS_CTL			0x64840
 #define   EDP_PSR_STATUS_STATE_MASK		(7<<29)
+#define   EDP_PSR_STATUS_STATE_IDLE		(0<<29)
+#define   EDP_PSR_STATUS_STATE_SRDONACK		(1<<29)
+#define   EDP_PSR_STATUS_STATE_SRDENT		(2<<29)
+#define   EDP_PSR_STATUS_STATE_BUFOFF		(3<<29)
+#define   EDP_PSR_STATUS_STATE_BUFON		(4<<29)
+#define   EDP_PSR_STATUS_STATE_AUXACK		(5<<29)
+#define   EDP_PSR_STATUS_STATE_SRDOFFACK	(6<<29)
+#define   EDP_PSR_STATUS_LINK_MASK		(3<<26)
+#define   EDP_PSR_STATUS_LINK_FULL_OFF		(0<<26)
+#define   EDP_PSR_STATUS_LINK_FULL_ON		(1<<26)
+#define   EDP_PSR_STATUS_LINK_STANDBY		(2<<26)
+#define   EDP_PSR_STATUS_MAX_SLEEP_TIMER_SHIFT	20
+#define   EDP_PSR_STATUS_MAX_SLEEP_TIMER_MASK	0x1f
+#define   EDP_PSR_STATUS_COUNT_SHIFT		16
+#define   EDP_PSR_STATUS_COUNT_MASK		0xf
+#define   EDP_PSR_STATUS_AUX_ERROR		(1<<15)
+#define   EDP_PSR_STATUS_AUX_SENDING		(1<<12)
+#define   EDP_PSR_STATUS_SENDING_IDLE		(1<<9)
+#define   EDP_PSR_STATUS_SENDING_TP2_TP3	(1<<8)
+#define   EDP_PSR_STATUS_SENDING_TP1		(1<<4)
+#define   EDP_PSR_STATUS_IDLE_MASK		0xf
+
+#define EDP_PSR_PERF_CNT		0x64844
+#define   EDP_PSR_PERF_CNT_MASK		0xffffff
 
 #define EDP_PSR_DEBUG_CTL		0x64860
 #define   EDP_PSR_DEBUG_MASK_LPSP	(1<<27)