drm/i915/dg1: Compute MEM Bandwidth using MCHBAR

The PUNIT FW is currently returning 0 for all memory bandwidth
parameters. Read the values directly from MCHBAR offsets 0x5918 and
0x4000(4).

v2 (Lucas): tidy up checking for ret slightly
v3 (Lucas):
  - Squash change to double the memory bandwidth based on
    MCHBAR Gear_type
  - Move ICL_GEAR_TYPE_MASK to the appropriate place and change prefix
    to DG1
  - Move register definitions to i915_reg.h
  - Make the MCHBAR path permanent for DG1
  - Convert to REG_BIT()/REG_GENMASK()
v4: Drop unneeded initializations

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Cc: Jani Saarinen <jani.saarinen@intel.com>
Signed-off-by: Clint Taylor <clinton.a.taylor@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210708175226.2451260-1-lucas.demarchi@intel.com

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

@@ -23,6 +23,41 @@ struct intel_qgv_info {
 	u8 t_bl;
 };
 
+static int dg1_mchbar_read_qgv_point_info(struct drm_i915_private *dev_priv,
+					  struct intel_qgv_point *sp,
+					  int point)
+{
+	u32 dclk_ratio, dclk_reference;
+	u32 val;
+
+	val = intel_uncore_read(&dev_priv->uncore, SA_PERF_STATUS_0_0_0_MCHBAR_PC);
+	dclk_ratio = REG_FIELD_GET(DG1_QCLK_RATIO_MASK, val);
+	if (val & DG1_QCLK_REFERENCE)
+		dclk_reference = 6; /* 6 * 16.666 MHz = 100 MHz */
+	else
+		dclk_reference = 8; /* 8 * 16.666 MHz = 133 MHz */
+	sp->dclk = dclk_ratio * dclk_reference;
+
+	val = intel_uncore_read(&dev_priv->uncore, SKL_MC_BIOS_DATA_0_0_0_MCHBAR_PCU);
+	if (val & DG1_GEAR_TYPE)
+		sp->dclk *= 2;
+
+	if (sp->dclk == 0)
+		return -EINVAL;
+
+	val = intel_uncore_read(&dev_priv->uncore, MCHBAR_CH0_CR_TC_PRE_0_0_0_MCHBAR);
+	sp->t_rp = REG_FIELD_GET(DG1_DRAM_T_RP_MASK, val);
+	sp->t_rdpre = REG_FIELD_GET(DG1_DRAM_T_RDPRE_MASK, val);
+
+	val = intel_uncore_read(&dev_priv->uncore, MCHBAR_CH0_CR_TC_PRE_0_0_0_MCHBAR_HIGH);
+	sp->t_rcd = REG_FIELD_GET(DG1_DRAM_T_RCD_MASK, val);
+	sp->t_ras = REG_FIELD_GET(DG1_DRAM_T_RAS_MASK, val);
+
+	sp->t_rc = sp->t_rp + sp->t_ras;
+
+	return 0;
+}
+
 static int icl_pcode_read_qgv_point_info(struct drm_i915_private *dev_priv,
 					 struct intel_qgv_point *sp,
 					 int point)
@@ -99,7 +134,11 @@ static int icl_get_qgv_points(struct drm_i915_private *dev_priv,
 	for (i = 0; i < qi->num_points; i++) {
 		struct intel_qgv_point *sp = &qi->points[i];
 
-		ret = icl_pcode_read_qgv_point_info(dev_priv, sp, i);
+		if (IS_DG1(dev_priv))
+			ret = dg1_mchbar_read_qgv_point_info(dev_priv, sp, i);
+		else
+			ret = icl_pcode_read_qgv_point_info(dev_priv, sp, i);
+
 		if (ret)
 			return ret;
 

drivers/gpu/drm/i915/i915_reg.h

@@ -11060,6 +11060,7 @@ enum skl_power_gate {
 #define SKL_MEMORY_FREQ_MULTIPLIER_HZ		266666666
 #define SKL_MC_BIOS_DATA_0_0_0_MCHBAR_PCU	_MMIO(MCHBAR_MIRROR_BASE_SNB + 0x5E04)
 #define  SKL_REQ_DATA_MASK			(0xF << 0)
+#define  DG1_GEAR_TYPE				REG_BIT(16)
 
 #define SKL_MAD_INTER_CHANNEL_0_0_0_MCHBAR_MCMAIN _MMIO(MCHBAR_MIRROR_BASE_SNB + 0x5000)
 #define  SKL_DRAM_DDR_TYPE_MASK			(0x3 << 0)
@@ -11095,6 +11096,17 @@ enum skl_power_gate {
 #define  CNL_DRAM_RANK_3			(0x2 << 9)
 #define  CNL_DRAM_RANK_4			(0x3 << 9)
 
+#define SA_PERF_STATUS_0_0_0_MCHBAR_PC		_MMIO(MCHBAR_MIRROR_BASE_SNB + 0x5918)
+#define  DG1_QCLK_RATIO_MASK			REG_GENMASK(9, 2)
+#define  DG1_QCLK_REFERENCE			REG_BIT(10)
+
+#define MCHBAR_CH0_CR_TC_PRE_0_0_0_MCHBAR	_MMIO(MCHBAR_MIRROR_BASE_SNB + 0x4000)
+#define   DG1_DRAM_T_RDPRE_MASK			REG_GENMASK(16, 11)
+#define   DG1_DRAM_T_RP_MASK			REG_GENMASK(6, 0)
+#define MCHBAR_CH0_CR_TC_PRE_0_0_0_MCHBAR_HIGH	_MMIO(MCHBAR_MIRROR_BASE_SNB + 0x4004)
+#define   DG1_DRAM_T_RCD_MASK			REG_GENMASK(15, 9)
+#define   DG1_DRAM_T_RAS_MASK			REG_GENMASK(8, 1)
+
 /*
  * Please see hsw_read_dcomp() and hsw_write_dcomp() before using this register,
  * since on HSW we can't write to it using intel_uncore_write.