drm/i915/vdsc: Add function to read any PPS register

Add function to read any PPS register based on the
intel_dsc_pps enum provided. Add a function which will call the
new pps read function and place it in crtc state. Only PPS0 and
PPS1 are readout the rest of the registers will be read in upcoming
patches.

--v2
-Changes in read function as PPS enum is removed
-Initialize pps_val as 0 in pps_read func itself [Jani]
-Create a function that gets the required register and call that
in the common read function [Jani]
-Move the drm_WARN_ON one abstraction layer above [Jani]

--v3
-Send both reg values regardless of dsc engine no [Jani]
-Don't use num_vdsc_instances stick to dsc_split field [Ankit]

--v4
-Manipulate the reg values instead of creating MACRO to change
name of pps [Ankit]

--v5
-Read dsc reg values using array rather than individual variables
[Ankit]
-Loop the verification of all dsc engine reads to future proof it
[Ankit]
-Keep the fix me comment in this patch and remove it in later one
where we add other readouts [Ankit]
-Add switch statement that fills in the required registers based on
no of vdsc engines per pipe.

--v7
-Pass no of vdsc instances from read_reg function [Ankit]
-Fix issue where arrays do not get freed on return for read_and_verify
func [Ankit]

--v8
-Simplify reading and verifying of register and remove dynamically
allocated arrays [Jani]
-Remove no_ from no_vdsc_per_pipe and wherever else it applies [Ankit]

--v9
-change variable name to dsc_reg_size rather than vdsc_per_pipe [Ankit]

--v10
-remove switch case as we never enter case1 [Ankit]

--v11
-Add _ prefix for register that are not supposed to be used directly
[Jani]
-Remove REG suffix from register macros [Jani]
-Do not duplicate register read [Jani]

--v12
-Use vdsc_per_pipe rather than array size of dsc_reg [Jani]
Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: Animesh Manna <animesh.manna@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230828054300.560559-5-suraj.kandpal@intel.com

drivers/gpu/drm/i915/display/intel_vdsc.c

@@ -371,6 +371,28 @@ int intel_dsc_get_num_vdsc_instances(const struct intel_crtc_state *crtc_state)
 	return num_vdsc_instances;
 }
 
+static void intel_dsc_get_pps_reg(const struct intel_crtc_state *crtc_state, int pps,
+				  i915_reg_t *dsc_reg, int vdsc_per_pipe)
+{
+	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
+	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
+	enum pipe pipe = crtc->pipe;
+	bool pipe_dsc;
+
+	pipe_dsc = is_pipe_dsc(crtc, cpu_transcoder);
+
+	switch (vdsc_per_pipe) {
+	case 2:
+		dsc_reg[1] = pipe_dsc ? ICL_DSC1_PPS(pipe, pps) : DSCC_PPS(pps);
+		fallthrough;
+	case 1:
+		dsc_reg[0] = pipe_dsc ? ICL_DSC0_PPS(pipe, pps) : DSCA_PPS(pps);
+		break;
+	default:
+		MISSING_CASE(vdsc_per_pipe);
+	}
+}
+
 static void intel_dsc_pps_configure(const struct intel_crtc_state *crtc_state)
 {
 	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
@@ -1000,17 +1022,72 @@ void intel_dsc_disable(const struct intel_crtc_state *old_crtc_state)
 	}
 }
 
+static bool intel_dsc_read_pps_reg(struct intel_crtc_state *crtc_state,
+				   int pps, u32 *pps_val)
+{
+	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
+	struct drm_i915_private *i915 = to_i915(crtc->base.dev);
+	const int vdsc_per_pipe = intel_dsc_get_vdsc_per_pipe(crtc_state);
+	i915_reg_t dsc_reg[2];
+	int i;
+
+	*pps_val = 0;
+	drm_WARN_ON_ONCE(&i915->drm, ARRAY_SIZE(dsc_reg) < vdsc_per_pipe);
+
+	intel_dsc_get_pps_reg(crtc_state, pps, dsc_reg, vdsc_per_pipe);
+
+	for (i = 0; i < min_t(int, ARRAY_SIZE(dsc_reg), vdsc_per_pipe); i++) {
+		u32 pps_temp;
+
+		pps_temp = intel_de_read(i915, dsc_reg[i]);
+
+		if (i == 0)
+			*pps_val = pps_temp;
+		else if (pps_temp != *pps_val)
+			return false;
+	}
+
+	return true;
+}
+
+static void intel_dsc_read_and_verify_pps_reg(struct intel_crtc_state *crtc_state,
+					      int pps, u32 *pps_val)
+{
+	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
+	struct drm_i915_private *i915 = to_i915(crtc->base.dev);
+	int ret;
+
+	ret = intel_dsc_read_pps_reg(crtc_state, pps, pps_val);
+	drm_WARN_ON(&i915->drm, !ret);
+}
+
+static void intel_dsc_get_pps_config(struct intel_crtc_state *crtc_state)
+{
+	struct drm_dsc_config *vdsc_cfg = &crtc_state->dsc.config;
+	u32 pps_temp1, pps_temp2;
+
+	/* FIXME: add more state readout as needed */
+
+	/* Readout PPS_0 and PPS_1 registers */
+	intel_dsc_read_and_verify_pps_reg(crtc_state, 0, &pps_temp1);
+	intel_dsc_read_and_verify_pps_reg(crtc_state, 1, &pps_temp2);
+
+	vdsc_cfg->bits_per_pixel = pps_temp2;
+
+	if (pps_temp1 & DSC_NATIVE_420_ENABLE)
+		vdsc_cfg->bits_per_pixel >>= 1;
+
+	crtc_state->dsc.compressed_bpp = vdsc_cfg->bits_per_pixel >> 4;
+}
+
 void intel_dsc_get_config(struct intel_crtc_state *crtc_state)
 {
 	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
-	struct drm_dsc_config *vdsc_cfg = &crtc_state->dsc.config;
 	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
-	enum pipe pipe = crtc->pipe;
 	enum intel_display_power_domain power_domain;
 	intel_wakeref_t wakeref;
-	u32 dss_ctl1, dss_ctl2, pps0 = 0, pps1 = 0, pps_temp0, pps_temp1;
-	int vdsc_instances_per_pipe;
+	u32 dss_ctl1, dss_ctl2;
 
 	if (!intel_dsc_source_support(crtc_state))
 		return;
@@ -1031,38 +1108,7 @@ void intel_dsc_get_config(struct intel_crtc_state *crtc_state)
 	crtc_state->dsc.dsc_split = (dss_ctl2 & RIGHT_BRANCH_VDSC_ENABLE) &&
 		(dss_ctl1 & JOINER_ENABLE);
 
-	/* FIXME: add more state readout as needed */
-
-	vdsc_instances_per_pipe = intel_dsc_get_vdsc_per_pipe(crtc_state);
-
-	/* PPS0 & PPS1 */
-	if (!is_pipe_dsc(crtc, cpu_transcoder)) {
-		pps1 = intel_de_read(dev_priv, DSCA_PICTURE_PARAMETER_SET_1);
-		if (vdsc_instances_per_pipe > 1) {
-			pps_temp1 = intel_de_read(dev_priv, DSCC_PICTURE_PARAMETER_SET_1);
-			drm_WARN_ON(&dev_priv->drm, pps1 != pps_temp1);
-		}
-	} else {
-		pps0 = intel_de_read(dev_priv,
-				     ICL_DSC0_PICTURE_PARAMETER_SET_0(pipe));
-		pps1 = intel_de_read(dev_priv,
-				     ICL_DSC0_PICTURE_PARAMETER_SET_1(pipe));
-		if (vdsc_instances_per_pipe > 1) {
-			pps_temp0 = intel_de_read(dev_priv,
-						  ICL_DSC1_PICTURE_PARAMETER_SET_0(pipe));
-			pps_temp1 = intel_de_read(dev_priv,
-						  ICL_DSC1_PICTURE_PARAMETER_SET_1(pipe));
-			drm_WARN_ON(&dev_priv->drm, pps0 != pps_temp0);
-			drm_WARN_ON(&dev_priv->drm, pps1 != pps_temp1);
-		}
-	}
-
-	vdsc_cfg->bits_per_pixel = pps1;
-
-	if (pps0 & DSC_NATIVE_420_ENABLE)
-		vdsc_cfg->bits_per_pixel >>= 1;
-
-	crtc_state->dsc.compressed_bpp = vdsc_cfg->bits_per_pixel >> 4;
+	intel_dsc_get_pps_config(crtc_state);
 out:
 	intel_display_power_put(dev_priv, power_domain, wakeref);
 }

drivers/gpu/drm/i915/display/intel_vdsc_regs.h

@@ -78,6 +78,10 @@
 /* Icelake Display Stream Compression Registers */
 #define DSCA_PICTURE_PARAMETER_SET_0		_MMIO(0x6B200)
 #define DSCC_PICTURE_PARAMETER_SET_0		_MMIO(0x6BA00)
+#define _DSCA_PPS_0				0x6B200
+#define _DSCC_PPS_0				0x6BA00
+#define DSCA_PPS(pps)				_MMIO(_DSCA_PPS_0 + (pps) * 4)
+#define DSCC_PPS(pps)				_MMIO(_DSCC_PPS_0 + (pps) * 4)
 #define _ICL_DSC0_PICTURE_PARAMETER_SET_0_PB	0x78270
 #define _ICL_DSC1_PICTURE_PARAMETER_SET_0_PB	0x78370
 #define _ICL_DSC0_PICTURE_PARAMETER_SET_0_PC	0x78470
@@ -88,6 +92,14 @@
 #define ICL_DSC1_PICTURE_PARAMETER_SET_0(pipe)	_MMIO_PIPE((pipe) - PIPE_B, \
 							   _ICL_DSC1_PICTURE_PARAMETER_SET_0_PB, \
 							   _ICL_DSC1_PICTURE_PARAMETER_SET_0_PC)
+#define _ICL_DSC0_PPS_0(pipe)			_PICK_EVEN((pipe) - PIPE_B, \
+							   _ICL_DSC0_PICTURE_PARAMETER_SET_0_PB, \
+							   _ICL_DSC0_PICTURE_PARAMETER_SET_0_PC)
+#define _ICL_DSC1_PPS_0(pipe)			_PICK_EVEN((pipe) - PIPE_B, \
+							   _ICL_DSC1_PICTURE_PARAMETER_SET_0_PB, \
+							   _ICL_DSC1_PICTURE_PARAMETER_SET_0_PC)
+#define  ICL_DSC0_PPS(pipe, pps)		_MMIO(_ICL_DSC0_PPS_0(pipe) + ((pps) * 4))
+#define  ICL_DSC1_PPS(pipe, pps)		_MMIO(_ICL_DSC1_PPS_0(pipe) + ((pps) * 4))
 #define  DSC_NATIVE_422_ENABLE		BIT(23)
 #define  DSC_NATIVE_420_ENABLE		BIT(22)
 #define  DSC_ALT_ICH_SEL		(1 << 20)