[PATCH v2 5/6] drm/komeda: Add engine clock requirement check for the downscaling

From: james qian wang (Arm Technology China)
Date: Thu May 23 2019 - 07:13:25 EST


For downscaling there is a restriction, the downscaling needed engine
clock can not acceed the real engine clock, and the clock requirement
mostly depend on the specific HW, to solve this problem:
1. Add a pipeline func - downscaling_clk_check for CORE to query the real
HW if downscaling can be supported.
2. Add new property clock ratio which is the ratio of:
(mclk << 32) / pxlclk
then User driver can use this ratio to do the clock check to avoid post
an invalid downscaling to kernel.

v2: Rebase and Delete debug print

Signed-off-by: James Qian Wang (Arm Technology China) <james.qian.wang@xxxxxxx>
---
.../arm/display/komeda/d71/d71_component.c | 45 +++++++++++++
.../gpu/drm/arm/display/komeda/d71/d71_dev.c | 2 +-
.../gpu/drm/arm/display/komeda/d71/d71_dev.h | 2 +
.../gpu/drm/arm/display/komeda/komeda_crtc.c | 66 ++++++++++++++++++-
.../gpu/drm/arm/display/komeda/komeda_kms.h | 8 +++
.../drm/arm/display/komeda/komeda_pipeline.h | 8 ++-
.../display/komeda/komeda_pipeline_state.c | 17 ++++-
7 files changed, 142 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/arm/display/komeda/d71/d71_component.c b/drivers/gpu/drm/arm/display/komeda/d71/d71_component.c
index 0bf5c7baedb5..2ea282c6a156 100644
--- a/drivers/gpu/drm/arm/display/komeda/d71/d71_component.c
+++ b/drivers/gpu/drm/arm/display/komeda/d71/d71_component.c
@@ -677,6 +677,47 @@ static int d71_scaler_init(struct d71_dev *d71,
return 0;
}

+static int d71_downscaling_clk_check(struct komeda_pipeline *pipe,
+ struct drm_display_mode *mode,
+ unsigned long mclk_rate,
+ struct komeda_data_flow_cfg *dflow)
+{
+ u32 h_in = dflow->in_w;
+ u32 v_in = dflow->in_h;
+ u32 v_out = dflow->out_h;
+ u64 fraction, denominator;
+
+ /* D71 downscaling must satisfy the following equation
+ *
+ * MCLK h_in * v_in
+ * ------- >= ---------------------------------------------
+ * PXLCLK (h_total - (1 + 2 * v_in / v_out)) * v_out
+ *
+ * In only horizontal downscaling situation, the right side should be
+ * multiplied by (h_total - 3) / (h_active - 3), then equation becomes
+ *
+ * MCLK h_in
+ * ------- >= ----------------
+ * PXLCLK (h_active - 3)
+ *
+ * To avoid precision lost the equation 1 will be convert to:
+ *
+ * MCLK h_in * v_in
+ * ------- >= -----------------------------------
+ * PXLCLK (h_total -1 ) * v_out - 2 * v_in
+ */
+ if (v_in == v_out) {
+ fraction = h_in;
+ denominator = mode->hdisplay - 3;
+ } else {
+ fraction = h_in * v_in;
+ denominator = (mode->htotal - 1) * v_out - 2 * v_in;
+ }
+
+ return mclk_rate * denominator >= mode->clock * 1000 * fraction ?
+ 0 : -EINVAL;
+}
+
static void d71_improc_update(struct komeda_component *c,
struct komeda_component_state *state)
{
@@ -939,3 +980,7 @@ int d71_probe_block(struct d71_dev *d71,

return err;
}
+
+const struct komeda_pipeline_funcs d71_pipeline_funcs = {
+ .downscaling_clk_check = d71_downscaling_clk_check,
+};
diff --git a/drivers/gpu/drm/arm/display/komeda/d71/d71_dev.c b/drivers/gpu/drm/arm/display/komeda/d71/d71_dev.c
index 3a7248d42376..1c914f8ca016 100644
--- a/drivers/gpu/drm/arm/display/komeda/d71/d71_dev.c
+++ b/drivers/gpu/drm/arm/display/komeda/d71/d71_dev.c
@@ -390,7 +390,7 @@ static int d71_enum_resources(struct komeda_dev *mdev)

for (i = 0; i < d71->num_pipelines; i++) {
pipe = komeda_pipeline_add(mdev, sizeof(struct d71_pipeline),
- NULL);
+ &d71_pipeline_funcs);
if (IS_ERR(pipe)) {
err = PTR_ERR(pipe);
goto err_cleanup;
diff --git a/drivers/gpu/drm/arm/display/komeda/d71/d71_dev.h b/drivers/gpu/drm/arm/display/komeda/d71/d71_dev.h
index 7465c57d9774..84f1878b647d 100644
--- a/drivers/gpu/drm/arm/display/komeda/d71/d71_dev.h
+++ b/drivers/gpu/drm/arm/display/komeda/d71/d71_dev.h
@@ -43,6 +43,8 @@ struct d71_dev {

#define to_d71_pipeline(x) container_of(x, struct d71_pipeline, base)

+extern const struct komeda_pipeline_funcs d71_pipeline_funcs;
+
int d71_probe_block(struct d71_dev *d71,
struct block_header *blk, u32 __iomem *reg);
void d71_read_block_header(u32 __iomem *reg, struct block_header *blk);
diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c b/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c
index 6712603b8c7a..24a961356cb3 100644
--- a/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c
+++ b/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c
@@ -18,6 +18,22 @@
#include "komeda_dev.h"
#include "komeda_kms.h"

+static void komeda_crtc_update_clock_ratio(struct komeda_crtc_state *kcrtc_st)
+{
+ u64 pxlclk, mclk;
+
+ if (!kcrtc_st->base.active) {
+ kcrtc_st->clock_ratio = 0;
+ return;
+ }
+
+ pxlclk = kcrtc_st->base.adjusted_mode.clock * 1000;
+ mclk = komeda_calc_mclk(kcrtc_st) << 32;
+
+ do_div(mclk, pxlclk);
+ kcrtc_st->clock_ratio = mclk;
+}
+
/**
* komeda_crtc_atomic_check - build display output data flow
* @crtc: DRM crtc
@@ -38,6 +54,9 @@ komeda_crtc_atomic_check(struct drm_crtc *crtc,
struct komeda_crtc_state *kcrtc_st = to_kcrtc_st(state);
int err;

+ if (drm_atomic_crtc_needs_modeset(state))
+ komeda_crtc_update_clock_ratio(kcrtc_st);
+
if (state->active) {
err = komeda_build_display_data_flow(kcrtc, kcrtc_st);
if (err)
@@ -52,11 +71,12 @@ komeda_crtc_atomic_check(struct drm_crtc *crtc,
return 0;
}

-static u32 komeda_calc_mclk(struct komeda_crtc_state *kcrtc_st)
+unsigned long komeda_calc_mclk(struct komeda_crtc_state *kcrtc_st)
{
- unsigned long mclk = kcrtc_st->base.adjusted_mode.clock * 1000;
+ struct komeda_dev *mdev = kcrtc_st->base.crtc->dev->dev_private;
+ unsigned long pxlclk = kcrtc_st->base.adjusted_mode.clock;

- return mclk;
+ return clk_round_rate(mdev->mclk, pxlclk * 1000);
}

/* For active a crtc, mainly need two parts of preparation
@@ -404,6 +424,7 @@ komeda_crtc_atomic_duplicate_state(struct drm_crtc *crtc)
__drm_atomic_helper_crtc_duplicate_state(crtc, &new->base);

new->affected_pipes = old->active_pipes;
+ new->clock_ratio = old->clock_ratio;

return &new->base;
}
@@ -432,6 +453,24 @@ static void komeda_crtc_vblank_disable(struct drm_crtc *crtc)
mdev->funcs->on_off_vblank(mdev, kcrtc->master->id, false);
}

+static int
+komeda_crtc_atomic_get_property(struct drm_crtc *crtc,
+ const struct drm_crtc_state *state,
+ struct drm_property *property, uint64_t *val)
+{
+ struct komeda_crtc *kcrtc = to_kcrtc(crtc);
+ struct komeda_crtc_state *kcrtc_st = to_kcrtc_st(state);
+
+ if (property == kcrtc->clock_ratio_property) {
+ *val = kcrtc_st->clock_ratio;
+ } else {
+ DRM_DEBUG_DRIVER("Unknown property %s\n", property->name);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
static const struct drm_crtc_funcs komeda_crtc_funcs = {
.gamma_set = drm_atomic_helper_legacy_gamma_set,
.destroy = drm_crtc_cleanup,
@@ -442,6 +481,7 @@ static const struct drm_crtc_funcs komeda_crtc_funcs = {
.atomic_destroy_state = komeda_crtc_atomic_destroy_state,
.enable_vblank = komeda_crtc_vblank_enable,
.disable_vblank = komeda_crtc_vblank_disable,
+ .atomic_get_property = komeda_crtc_atomic_get_property,
};

int komeda_kms_setup_crtcs(struct komeda_kms_dev *kms,
@@ -477,6 +517,22 @@ int komeda_kms_setup_crtcs(struct komeda_kms_dev *kms,
return 0;
}

+static int komeda_crtc_create_clock_ratio_property(struct komeda_crtc *kcrtc)
+{
+ struct drm_crtc *crtc = &kcrtc->base;
+ struct drm_property *prop;
+
+ prop = drm_property_create_range(crtc->dev, DRM_MODE_PROP_ATOMIC,
+ "CLOCK_RATIO", 0, U64_MAX);
+ if (!prop)
+ return -ENOMEM;
+
+ drm_object_attach_property(&crtc->base, prop, 0);
+ kcrtc->clock_ratio_property = prop;
+
+ return 0;
+}
+
static struct drm_plane *
get_crtc_primary(struct komeda_kms_dev *kms, struct komeda_crtc *crtc)
{
@@ -513,6 +569,10 @@ static int komeda_crtc_add(struct komeda_kms_dev *kms,

crtc->port = kcrtc->master->of_output_port;

+ err = komeda_crtc_create_clock_ratio_property(kcrtc);
+ if (err)
+ return err;
+
return 0;
}

diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_kms.h b/drivers/gpu/drm/arm/display/komeda/komeda_kms.h
index f16e9e577593..db59a9042beb 100644
--- a/drivers/gpu/drm/arm/display/komeda/komeda_kms.h
+++ b/drivers/gpu/drm/arm/display/komeda/komeda_kms.h
@@ -79,6 +79,9 @@ struct komeda_crtc {

/** @disable_done: this flip_done is for tracing the disable */
struct completion *disable_done;
+
+ /** @clock_ratio_property: property for ratio of (mclk << 32)/pxlclk */
+ struct drm_property *clock_ratio_property;
};

/**
@@ -101,6 +104,9 @@ struct komeda_crtc_state {
* the active pipelines in once display instance
*/
u32 active_pipes;
+
+ /** @clock_ratio: ratio of (mclk << 32)/pxlclk */
+ u64 clock_ratio;
};

/** struct komeda_kms_dev - for gather KMS related things */
@@ -142,6 +148,8 @@ is_only_changed_connector(struct drm_crtc_state *st, struct drm_connector *conn)
return BIT(drm_connector_index(conn)) == changed_connectors;
}

+unsigned long komeda_calc_mclk(struct komeda_crtc_state *kcrtc_st);
+
int komeda_kms_setup_crtcs(struct komeda_kms_dev *kms, struct komeda_dev *mdev);

int komeda_kms_add_crtcs(struct komeda_kms_dev *kms, struct komeda_dev *mdev);
diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_pipeline.h b/drivers/gpu/drm/arm/display/komeda/komeda_pipeline.h
index 9ffe11c9f386..d0bf7d5b39a7 100644
--- a/drivers/gpu/drm/arm/display/komeda/komeda_pipeline.h
+++ b/drivers/gpu/drm/arm/display/komeda/komeda_pipeline.h
@@ -316,8 +316,14 @@ struct komeda_data_flow_cfg {
u8 en_scaling : 1;
};

-/** struct komeda_pipeline_funcs */
struct komeda_pipeline_funcs {
+ /* check if the mclk (main engine clock) can satisfy the clock
+ * requirements of the downscaling that specified by dflow
+ */
+ int (*downscaling_clk_check)(struct komeda_pipeline *pipe,
+ struct drm_display_mode *mode,
+ unsigned long mclk_rate,
+ struct komeda_data_flow_cfg *dflow);
/* dump_register: Optional, dump registers to seq_file */
void (*dump_register)(struct komeda_pipeline *pipe,
struct seq_file *sf);
diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_pipeline_state.c b/drivers/gpu/drm/arm/display/komeda/komeda_pipeline_state.c
index 9f07ef65008f..01544c274848 100644
--- a/drivers/gpu/drm/arm/display/komeda/komeda_pipeline_state.c
+++ b/drivers/gpu/drm/arm/display/komeda/komeda_pipeline_state.c
@@ -387,6 +387,7 @@ static bool scaling_ratio_valid(u32 size_in, u32 size_out,

static int
komeda_scaler_check_cfg(struct komeda_scaler *scaler,
+ struct komeda_crtc_state *kcrtc_st,
struct komeda_data_flow_cfg *dflow)
{
u32 hsize_in, vsize_in, hsize_out, vsize_out;
@@ -428,6 +429,20 @@ komeda_scaler_check_cfg(struct komeda_scaler *scaler,
DRM_DEBUG_ATOMIC("Invalid vertical scaling ratio");
return -EINVAL;
}
+
+ if (hsize_in > hsize_out || vsize_in > vsize_out) {
+ struct komeda_pipeline *pipe = scaler->base.pipeline;
+ int err;
+
+ err = pipe->funcs->downscaling_clk_check(pipe,
+ &kcrtc_st->base.adjusted_mode,
+ komeda_calc_mclk(kcrtc_st), dflow);
+ if (err) {
+ DRM_DEBUG_ATOMIC("mclk can't satisfy the clock requirement of the downscaling\n");
+ return err;
+ }
+ }
+
return 0;
}

@@ -452,7 +467,7 @@ komeda_scaler_validate(void *user,
return -EINVAL;
}

- err = komeda_scaler_check_cfg(scaler, dflow);
+ err = komeda_scaler_check_cfg(scaler, kcrtc_st, dflow);
if (err)
return err;

--
2.17.1