[PATCH v8 13/20] drm/bridge: dw-hdmi-qp: Implement atomic_get_output_bus_fmts
Nicolas Frattaroli
nicolas.frattaroli at collabora.com
Mon Feb 16 05:01:27 PST 2026
The atomic_get_output_bus_fmts callback is used by the DRM bridge layer
to recursively select a suitable output format in a bridge chain.
As a bridge that outputs to HDMI, dw-hdmi-qp will have its output
formats determined by which formats the platform-specific integration of
the hardware supports, and the chosen HDMI output bit depth.
Implement this callback. The returned u32* buffer is supposed to be
freed by the caller of this callback, as specified by the callback's
documentation.
Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli at collabora.com>
---
drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c | 178 +++++++++++++++++++++++++++
1 file changed, 178 insertions(+)
diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
index d649a1cf07f5..4c00218e5fd7 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
@@ -11,6 +11,7 @@
#include <linux/export.h>
#include <linux/i2c.h>
#include <linux/irq.h>
+#include <linux/media-bus-format.h>
#include <linux/minmax.h>
#include <linux/module.h>
#include <linux/mutex.h>
@@ -749,6 +750,182 @@ static struct i2c_adapter *dw_hdmi_qp_i2c_adapter(struct dw_hdmi_qp *hdmi)
return adap;
}
+static int dw_hdmi_qp_config_avi_infoframe(struct dw_hdmi_qp *hdmi,
+ const u8 *buffer, size_t len)
+{
+ u32 val, i, j;
+
+ if (len != HDMI_INFOFRAME_SIZE(AVI)) {
+ dev_err(hdmi->dev, "failed to configure avi infoframe\n");
+ return -EINVAL;
+ }
+
+ /*
+ * DW HDMI QP IP uses a different byte format from standard AVI info
+ * frames, though generally the bits are in the correct bytes.
+ */
+ val = buffer[1] << 8 | buffer[2] << 16;
+ dw_hdmi_qp_write(hdmi, val, PKT_AVI_CONTENTS0);
+
+ for (i = 0; i < 4; i++) {
+ for (j = 0; j < 4; j++) {
+ if (i * 4 + j >= 14)
+ break;
+ if (!j)
+ val = buffer[i * 4 + j + 3];
+ val |= buffer[i * 4 + j + 3] << (8 * j);
+ }
+
+ dw_hdmi_qp_write(hdmi, val, PKT_AVI_CONTENTS1 + i * 4);
+ }
+
+ dw_hdmi_qp_mod(hdmi, 0, PKTSCHED_AVI_FIELDRATE, PKTSCHED_PKT_CONFIG1);
+
+ dw_hdmi_qp_mod(hdmi, PKTSCHED_AVI_TX_EN | PKTSCHED_GCP_TX_EN,
+ PKTSCHED_AVI_TX_EN | PKTSCHED_GCP_TX_EN, PKTSCHED_PKT_EN);
+
+ return 0;
+}
+
+static int dw_hdmi_qp_config_drm_infoframe(struct dw_hdmi_qp *hdmi,
+ const u8 *buffer, size_t len)
+{
+ u32 val, i;
+
+ if (len != HDMI_INFOFRAME_SIZE(DRM)) {
+ dev_err(hdmi->dev, "failed to configure drm infoframe\n");
+ return -EINVAL;
+ }
+
+ dw_hdmi_qp_mod(hdmi, 0, PKTSCHED_DRMI_TX_EN, PKTSCHED_PKT_EN);
+
+ val = buffer[1] << 8 | buffer[2] << 16;
+ dw_hdmi_qp_write(hdmi, val, PKT_DRMI_CONTENTS0);
+
+ for (i = 0; i <= buffer[2]; i++) {
+ if (i % 4 == 0)
+ val = buffer[3 + i];
+ val |= buffer[3 + i] << ((i % 4) * 8);
+
+ if ((i % 4 == 3) || i == buffer[2])
+ dw_hdmi_qp_write(hdmi, val,
+ PKT_DRMI_CONTENTS1 + ((i / 4) * 4));
+ }
+
+ dw_hdmi_qp_mod(hdmi, 0, PKTSCHED_DRMI_FIELDRATE, PKTSCHED_PKT_CONFIG1);
+ dw_hdmi_qp_mod(hdmi, PKTSCHED_DRMI_TX_EN, PKTSCHED_DRMI_TX_EN,
+ PKTSCHED_PKT_EN);
+
+ return 0;
+}
+
+/*
+ * Static values documented in the TRM
+ * Different values are only used for debug purposes
+ */
+#define DW_HDMI_QP_AUDIO_INFOFRAME_HB1 0x1
+#define DW_HDMI_QP_AUDIO_INFOFRAME_HB2 0xa
+
+static int dw_hdmi_qp_config_audio_infoframe(struct dw_hdmi_qp *hdmi,
+ const u8 *buffer, size_t len)
+{
+ /*
+ * AUDI_CONTENTS0: { RSV, HB2, HB1, RSV }
+ * AUDI_CONTENTS1: { PB3, PB2, PB1, PB0 }
+ * AUDI_CONTENTS2: { PB7, PB6, PB5, PB4 }
+ *
+ * PB0: CheckSum
+ * PB1: | CT3 | CT2 | CT1 | CT0 | F13 | CC2 | CC1 | CC0 |
+ * PB2: | F27 | F26 | F25 | SF2 | SF1 | SF0 | SS1 | SS0 |
+ * PB3: | F37 | F36 | F35 | F34 | F33 | F32 | F31 | F30 |
+ * PB4: | CA7 | CA6 | CA5 | CA4 | CA3 | CA2 | CA1 | CA0 |
+ * PB5: | DM_INH | LSV3 | LSV2 | LSV1 | LSV0 | F52 | F51 | F50 |
+ * PB6~PB10: Reserved
+ *
+ * AUDI_CONTENTS0 default value defined by HDMI specification,
+ * and shall only be changed for debug purposes.
+ */
+ u32 header_bytes = (DW_HDMI_QP_AUDIO_INFOFRAME_HB1 << 8) |
+ (DW_HDMI_QP_AUDIO_INFOFRAME_HB2 << 16);
+
+ regmap_bulk_write(hdmi->regm, PKT_AUDI_CONTENTS0, &header_bytes, 1);
+ regmap_bulk_write(hdmi->regm, PKT_AUDI_CONTENTS1, &buffer[3], 1);
+ regmap_bulk_write(hdmi->regm, PKT_AUDI_CONTENTS2, &buffer[4], 1);
+
+ /* Enable ACR, AUDI, AMD */
+ dw_hdmi_qp_mod(hdmi,
+ PKTSCHED_ACR_TX_EN | PKTSCHED_AUDI_TX_EN | PKTSCHED_AMD_TX_EN,
+ PKTSCHED_ACR_TX_EN | PKTSCHED_AUDI_TX_EN | PKTSCHED_AMD_TX_EN,
+ PKTSCHED_PKT_EN);
+
+ /* Enable AUDS */
+ dw_hdmi_qp_mod(hdmi, PKTSCHED_AUDS_TX_EN, PKTSCHED_AUDS_TX_EN, PKTSCHED_PKT_EN);
+
+ return 0;
+}
+
+static u32*
+dw_hdmi_qp_bridge_get_output_bus_fmts(struct drm_bridge *bridge,
+ struct drm_bridge_state *bridge_state,
+ struct drm_crtc_state *crtc_state,
+ struct drm_connector_state *conn_state,
+ unsigned int *num_output_fmts)
+{
+ unsigned int num_fmts = 0;
+ u32 *out_fmts;
+
+ /*
+ * bridge->supported_formats is a bit field of the HDMI_COLORSPACE_* enums.
+ * These enums are defined by the HDMI standard, and currently top out at
+ * 7. Consequently, BIT(7) is the highest bit that will be set here, unless
+ * the standard runs out of reserved pixel formats. Therefore, hweight8()
+ * will give an accurate count of how many bus formats we'll output.
+ */
+ out_fmts = kmalloc_array(hweight8(bridge->supported_formats), sizeof(u32),
+ GFP_KERNEL);
+ if (!out_fmts) {
+ *num_output_fmts = 0;
+ return NULL;
+ }
+
+ switch (conn_state->hdmi.output_bpc) {
+ case 12:
+ if (bridge->supported_formats & BIT(HDMI_COLORSPACE_RGB))
+ out_fmts[num_fmts++] = MEDIA_BUS_FMT_RGB121212_1X36;
+ if (bridge->supported_formats & BIT(HDMI_COLORSPACE_YUV444))
+ out_fmts[num_fmts++] = MEDIA_BUS_FMT_YUV12_1X36;
+ if (bridge->supported_formats & BIT(HDMI_COLORSPACE_YUV422))
+ out_fmts[num_fmts++] = MEDIA_BUS_FMT_UYVY12_1X24;
+ if (bridge->supported_formats & BIT(HDMI_COLORSPACE_YUV420))
+ out_fmts[num_fmts++] = MEDIA_BUS_FMT_UYYVYY12_0_5X36;
+ break;
+ case 10:
+ if (bridge->supported_formats & BIT(HDMI_COLORSPACE_RGB))
+ out_fmts[num_fmts++] = MEDIA_BUS_FMT_RGB101010_1X30;
+ if (bridge->supported_formats & BIT(HDMI_COLORSPACE_YUV444))
+ out_fmts[num_fmts++] = MEDIA_BUS_FMT_YUV10_1X30;
+ if (bridge->supported_formats & BIT(HDMI_COLORSPACE_YUV422))
+ out_fmts[num_fmts++] = MEDIA_BUS_FMT_UYVY10_1X20;
+ if (bridge->supported_formats & BIT(HDMI_COLORSPACE_YUV420))
+ out_fmts[num_fmts++] = MEDIA_BUS_FMT_UYYVYY10_0_5X30;
+ break;
+ default:
+ if (bridge->supported_formats & BIT(HDMI_COLORSPACE_RGB))
+ out_fmts[num_fmts++] = MEDIA_BUS_FMT_RGB888_1X24;
+ if (bridge->supported_formats & BIT(HDMI_COLORSPACE_YUV444))
+ out_fmts[num_fmts++] = MEDIA_BUS_FMT_YUV8_1X24;
+ if (bridge->supported_formats & BIT(HDMI_COLORSPACE_YUV422))
+ out_fmts[num_fmts++] = MEDIA_BUS_FMT_UYVY8_1X16;
+ if (bridge->supported_formats & BIT(HDMI_COLORSPACE_YUV420))
+ out_fmts[num_fmts++] = MEDIA_BUS_FMT_UYYVYY8_0_5X24;
+ break;
+ }
+
+ *num_output_fmts = num_fmts;
+
+ return out_fmts;
+}
+
static void dw_hdmi_qp_bridge_atomic_enable(struct drm_bridge *bridge,
struct drm_atomic_state *state)
{
@@ -1192,6 +1369,7 @@ static int dw_hdmi_qp_cec_transmit(struct drm_bridge *bridge, u8 attempts,
#endif /* CONFIG_DRM_DW_HDMI_QP_CEC */
static const struct drm_bridge_funcs dw_hdmi_qp_bridge_funcs = {
+ .atomic_get_output_bus_fmts = dw_hdmi_qp_bridge_get_output_bus_fmts,
.atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
.atomic_reset = drm_atomic_helper_bridge_reset,
--
2.53.0
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