1 files changed, 421 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/display/intel_bw.c b/drivers/gpu/drm/i915/display/intel_bw.c
new file mode 100644
index 000000000000..753ac3165061
--- /dev/null
+++ b/drivers/gpu/drm/i915/display/intel_bw.c
@@ -0,0 +1,421 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2019 Intel Corporation
+ */
+
+#include <drm/drm_atomic_state_helper.h>
+
+#include "intel_bw.h"
+#include "intel_drv.h"
+#include "intel_sideband.h"
+
+/* Parameters for Qclk Geyserville (QGV) */
+struct intel_qgv_point {
+	u16 dclk, t_rp, t_rdpre, t_rc, t_ras, t_rcd;
+};
+
+struct intel_qgv_info {
+	struct intel_qgv_point points[3];
+	u8 num_points;
+	u8 num_channels;
+	u8 t_bl;
+	enum intel_dram_type dram_type;
+};
+
+static int icl_pcode_read_mem_global_info(struct drm_i915_private *dev_priv,
+					  struct intel_qgv_info *qi)
+{
+	u32 val = 0;
+	int ret;
+
+	ret = sandybridge_pcode_read(dev_priv,
+				     ICL_PCODE_MEM_SUBSYSYSTEM_INFO |
+				     ICL_PCODE_MEM_SS_READ_GLOBAL_INFO,
+				     &val, NULL);
+	if (ret)
+		return ret;
+
+	switch (val & 0xf) {
+	case 0:
+		qi->dram_type = INTEL_DRAM_DDR4;
+		break;
+	case 1:
+		qi->dram_type = INTEL_DRAM_DDR3;
+		break;
+	case 2:
+		qi->dram_type = INTEL_DRAM_LPDDR3;
+		break;
+	case 3:
+		qi->dram_type = INTEL_DRAM_LPDDR3;
+		break;
+	default:
+		MISSING_CASE(val & 0xf);
+		break;
+	}
+
+	qi->num_channels = (val & 0xf0) >> 4;
+	qi->num_points = (val & 0xf00) >> 8;
+
+	qi->t_bl = qi->dram_type == INTEL_DRAM_DDR4 ? 4 : 8;
+
+	return 0;
+}
+
+static int icl_pcode_read_qgv_point_info(struct drm_i915_private *dev_priv,
+					 struct intel_qgv_point *sp,
+					 int point)
+{
+	u32 val = 0, val2;
+	int ret;
+
+	ret = sandybridge_pcode_read(dev_priv,
+				     ICL_PCODE_MEM_SUBSYSYSTEM_INFO |
+				     ICL_PCODE_MEM_SS_READ_QGV_POINT_INFO(point),
+				     &val, &val2);
+	if (ret)
+		return ret;
+
+	sp->dclk = val & 0xffff;
+	sp->t_rp = (val & 0xff0000) >> 16;
+	sp->t_rcd = (val & 0xff000000) >> 24;
+
+	sp->t_rdpre = val2 & 0xff;
+	sp->t_ras = (val2 & 0xff00) >> 8;
+
+	sp->t_rc = sp->t_rp + sp->t_ras;
+
+	return 0;
+}
+
+static int icl_get_qgv_points(struct drm_i915_private *dev_priv,
+			      struct intel_qgv_info *qi)
+{
+	int i, ret;
+
+	ret = icl_pcode_read_mem_global_info(dev_priv, qi);
+	if (ret)
+		return ret;
+
+	if (WARN_ON(qi->num_points > ARRAY_SIZE(qi->points)))
+		qi->num_points = ARRAY_SIZE(qi->points);
+
+	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 (ret)
+			return ret;
+
+		DRM_DEBUG_KMS("QGV %d: DCLK=%d tRP=%d tRDPRE=%d tRAS=%d tRCD=%d tRC=%d\n",
+			      i, sp->dclk, sp->t_rp, sp->t_rdpre, sp->t_ras,
+			      sp->t_rcd, sp->t_rc);
+	}
+
+	return 0;
+}
+
+static int icl_calc_bw(int dclk, int num, int den)
+{
+	/* multiples of 16.666MHz (100/6) */
+	return DIV_ROUND_CLOSEST(num * dclk * 100, den * 6);
+}
+
+static int icl_sagv_max_dclk(const struct intel_qgv_info *qi)
+{
+	u16 dclk = 0;
+	int i;
+
+	for (i = 0; i < qi->num_points; i++)
+		dclk = max(dclk, qi->points[i].dclk);
+
+	return dclk;
+}
+
+struct intel_sa_info {
+	u8 deburst, mpagesize, deprogbwlimit, displayrtids;
+};
+
+static const struct intel_sa_info icl_sa_info = {
+	.deburst = 8,
+	.mpagesize = 16,
+	.deprogbwlimit = 25, /* GB/s */
+	.displayrtids = 128,
+};
+
+static int icl_get_bw_info(struct drm_i915_private *dev_priv)
+{
+	struct intel_qgv_info qi = {};
+	const struct intel_sa_info *sa = &icl_sa_info;
+	bool is_y_tile = true; /* assume y tile may be used */
+	int num_channels;
+	int deinterleave;
+	int ipqdepth, ipqdepthpch;
+	int dclk_max;
+	int maxdebw;
+	int i, ret;
+
+	ret = icl_get_qgv_points(dev_priv, &qi);
+	if (ret) {
+		DRM_DEBUG_KMS("Failed to get memory subsystem information, ignoring bandwidth limits");
+		return ret;
+	}
+	num_channels = qi.num_channels;
+
+	deinterleave = DIV_ROUND_UP(num_channels, is_y_tile ? 4 : 2);
+	dclk_max = icl_sagv_max_dclk(&qi);
+
+	ipqdepthpch = 16;
+
+	maxdebw = min(sa->deprogbwlimit * 1000,
+		      icl_calc_bw(dclk_max, 16, 1) * 6 / 10); /* 60% */
+	ipqdepth = min(ipqdepthpch, sa->displayrtids / num_channels);
+
+	for (i = 0; i < ARRAY_SIZE(dev_priv->max_bw); i++) {
+		struct intel_bw_info *bi = &dev_priv->max_bw[i];
+		int clpchgroup;
+		int j;
+
+		clpchgroup = (sa->deburst * deinterleave / num_channels) << i;
+		bi->num_planes = (ipqdepth - clpchgroup) / clpchgroup + 1;
+
+		for (j = 0; j < qi.num_points; j++) {
+			const struct intel_qgv_point *sp = &qi.points[j];
+			int ct, bw;
+
+			/*
+			 * Max row cycle time
+			 *
+			 * FIXME what is the logic behind the
+			 * assumed burst length?
+			 */
+			ct = max_t(int, sp->t_rc, sp->t_rp + sp->t_rcd +
+				   (clpchgroup - 1) * qi.t_bl + sp->t_rdpre);
+			bw = icl_calc_bw(sp->dclk, clpchgroup * 32 * num_channels, ct);
+
+			bi->deratedbw[j] = min(maxdebw,
+					       bw * 9 / 10); /* 90% */
+
+			DRM_DEBUG_KMS("BW%d / QGV %d: num_planes=%d deratedbw=%d\n",
+				      i, j, bi->num_planes, bi->deratedbw[j]);
+		}
+
+		if (bi->num_planes == 1)
+			break;
+	}
+
+	return 0;
+}
+
+static unsigned int icl_max_bw(struct drm_i915_private *dev_priv,
+			       int num_planes, int qgv_point)
+{
+	int i;
+
+	/* Did we initialize the bw limits successfully? */
+	if (dev_priv->max_bw[0].num_planes == 0)
+		return UINT_MAX;
+
+	for (i = 0; i < ARRAY_SIZE(dev_priv->max_bw); i++) {
+		const struct intel_bw_info *bi =
+			&dev_priv->max_bw[i];
+
+		if (num_planes >= bi->num_planes)
+			return bi->deratedbw[qgv_point];
+	}
+
+	return 0;
+}
+
+void intel_bw_init_hw(struct drm_i915_private *dev_priv)
+{
+	if (IS_GEN(dev_priv, 11))
+		icl_get_bw_info(dev_priv);
+}
+
+static unsigned int intel_max_data_rate(struct drm_i915_private *dev_priv,
+					int num_planes)
+{
+	if (IS_GEN(dev_priv, 11))
+		/*
+		 * FIXME with SAGV disabled maybe we can assume
+		 * point 1 will always be used? Seems to match
+		 * the behaviour observed in the wild.
+		 */
+		return min3(icl_max_bw(dev_priv, num_planes, 0),
+			    icl_max_bw(dev_priv, num_planes, 1),
+			    icl_max_bw(dev_priv, num_planes, 2));
+	else
+		return UINT_MAX;
+}
+
+static unsigned int intel_bw_crtc_num_active_planes(const struct intel_crtc_state *crtc_state)
+{
+	/*
+	 * We assume cursors are small enough
+	 * to not not cause bandwidth problems.
+	 */
+	return hweight8(crtc_state->active_planes & ~BIT(PLANE_CURSOR));
+}
+
+static unsigned int intel_bw_crtc_data_rate(const struct intel_crtc_state *crtc_state)
+{
+	struct intel_crtc *crtc = to_intel_crtc(crtc_state->base.crtc);
+	unsigned int data_rate = 0;
+	enum plane_id plane_id;
+
+	for_each_plane_id_on_crtc(crtc, plane_id) {
+		/*
+		 * We assume cursors are small enough
+		 * to not not cause bandwidth problems.
+		 */
+		if (plane_id == PLANE_CURSOR)
+			continue;
+
+		data_rate += crtc_state->data_rate[plane_id];
+	}
+
+	return data_rate;
+}
+
+void intel_bw_crtc_update(struct intel_bw_state *bw_state,
+			  const struct intel_crtc_state *crtc_state)
+{
+	struct intel_crtc *crtc = to_intel_crtc(crtc_state->base.crtc);
+
+	bw_state->data_rate[crtc->pipe] =
+		intel_bw_crtc_data_rate(crtc_state);
+	bw_state->num_active_planes[crtc->pipe] =
+		intel_bw_crtc_num_active_planes(crtc_state);
+
+	DRM_DEBUG_KMS("pipe %c data rate %u num active planes %u\n",
+		      pipe_name(crtc->pipe),
+		      bw_state->data_rate[crtc->pipe],
+		      bw_state->num_active_planes[crtc->pipe]);
+}
+
+static unsigned int intel_bw_num_active_planes(struct drm_i915_private *dev_priv,
+					       const struct intel_bw_state *bw_state)
+{
+	unsigned int num_active_planes = 0;
+	enum pipe pipe;
+
+	for_each_pipe(dev_priv, pipe)
+		num_active_planes += bw_state->num_active_planes[pipe];
+
+	return num_active_planes;
+}
+
+static unsigned int intel_bw_data_rate(struct drm_i915_private *dev_priv,
+				       const struct intel_bw_state *bw_state)
+{
+	unsigned int data_rate = 0;
+	enum pipe pipe;
+
+	for_each_pipe(dev_priv, pipe)
+		data_rate += bw_state->data_rate[pipe];
+
+	return data_rate;
+}
+
+int intel_bw_atomic_check(struct intel_atomic_state *state)
+{
+	struct drm_i915_private *dev_priv = to_i915(state->base.dev);
+	struct intel_crtc_state *new_crtc_state, *old_crtc_state;
+	struct intel_bw_state *bw_state = NULL;
+	unsigned int data_rate, max_data_rate;
+	unsigned int num_active_planes;
+	struct intel_crtc *crtc;
+	int i;
+
+	/* FIXME earlier gens need some checks too */
+	if (INTEL_GEN(dev_priv) < 11)
+		return 0;
+
+	for_each_oldnew_intel_crtc_in_state(state, crtc, old_crtc_state,
+					    new_crtc_state, i) {
+		unsigned int old_data_rate =
+			intel_bw_crtc_data_rate(old_crtc_state);
+		unsigned int new_data_rate =
+			intel_bw_crtc_data_rate(new_crtc_state);
+		unsigned int old_active_planes =
+			intel_bw_crtc_num_active_planes(old_crtc_state);
+		unsigned int new_active_planes =
+			intel_bw_crtc_num_active_planes(new_crtc_state);
+
+		/*
+		 * Avoid locking the bw state when
+		 * nothing significant has changed.
+		 */
+		if (old_data_rate == new_data_rate &&
+		    old_active_planes == new_active_planes)
+			continue;
+
+		bw_state  = intel_atomic_get_bw_state(state);
+		if (IS_ERR(bw_state))
+			return PTR_ERR(bw_state);
+
+		bw_state->data_rate[crtc->pipe] = new_data_rate;
+		bw_state->num_active_planes[crtc->pipe] = new_active_planes;
+
+		DRM_DEBUG_KMS("pipe %c data rate %u num active planes %u\n",
+			      pipe_name(crtc->pipe),
+			      bw_state->data_rate[crtc->pipe],
+			      bw_state->num_active_planes[crtc->pipe]);
+	}
+
+	if (!bw_state)
+		return 0;
+
+	data_rate = intel_bw_data_rate(dev_priv, bw_state);
+	num_active_planes = intel_bw_num_active_planes(dev_priv, bw_state);
+
+	max_data_rate = intel_max_data_rate(dev_priv, num_active_planes);
+
+	data_rate = DIV_ROUND_UP(data_rate, 1000);
+
+	if (data_rate > max_data_rate) {
+		DRM_DEBUG_KMS("Bandwidth %u MB/s exceeds max available %d MB/s (%d active planes)\n",
+			      data_rate, max_data_rate, num_active_planes);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static struct drm_private_state *intel_bw_duplicate_state(struct drm_private_obj *obj)
+{
+	struct intel_bw_state *state;
+
+	state = kmemdup(obj->state, sizeof(*state), GFP_KERNEL);
+	if (!state)
+		return NULL;
+
+	__drm_atomic_helper_private_obj_duplicate_state(obj, &state->base);
+
+	return &state->base;
+}
+
+static void intel_bw_destroy_state(struct drm_private_obj *obj,
+				   struct drm_private_state *state)
+{
+	kfree(state);
+}
+
+static const struct drm_private_state_funcs intel_bw_funcs = {
+	.atomic_duplicate_state = intel_bw_duplicate_state,
+	.atomic_destroy_state = intel_bw_destroy_state,
+};
+
+int intel_bw_init(struct drm_i915_private *dev_priv)
+{
+	struct intel_bw_state *state;
+
+	state = kzalloc(sizeof(*state), GFP_KERNEL);
+	if (!state)
+		return -ENOMEM;
+
+	drm_atomic_private_obj_init(&dev_priv->drm, &dev_priv->bw_obj,
+				    &state->base, &intel_bw_funcs);
+
+	return 0;
+}