Re: [PATCH] drm/rockchip: cdn-dp: send audio infoframe to sink

From: Chris Zhong
Date: Tue Jul 18 2017 - 07:36:36 EST

Hi Sean

Thanks for your replying.


On Tuesday, July 18, 2017 04:23 AM, Sean Paul wrote:
On Sat, Jul 15, 2017 at 07:00:18PM +0800, Chris Zhong wrote:
Some DP/HDMI sink need to receive the audio infoframe to play sound,
especially some multi-channel AV receiver, they need the
channel_allocation from infoframe to config the speakers. Send the
audio infoframe via SDP will make them work properly.

Signed-off-by: Chris Zhong <zyw@xxxxxxxxxxxxxx>
Hi Chris,
Thanks for the patch, please see comments below.

---

drivers/gpu/drm/rockchip/cdn-dp-core.c | 20 ++++++++++++++++++++
drivers/gpu/drm/rockchip/cdn-dp-reg.c | 19 +++++++++++++++++++
drivers/gpu/drm/rockchip/cdn-dp-reg.h | 6 ++++++
3 files changed, 45 insertions(+)

diff --git a/drivers/gpu/drm/rockchip/cdn-dp-core.c b/drivers/gpu/drm/rockchip/cdn-dp-core.c
index 9b0b058..e59ca47 100644
--- a/drivers/gpu/drm/rockchip/cdn-dp-core.c
+++ b/drivers/gpu/drm/rockchip/cdn-dp-core.c
@@ -802,6 +802,7 @@ static int cdn_dp_audio_hw_params(struct device *dev, void *data,
.sample_rate = params->sample_rate,
.channels = params->channels,
};
+ u8 buffer[14];
Why 14?

I think you should probably have buffer[HDMI_AUDIO_INFOFRAME_SIZE +
SDP_HEADER_SIZE] so the reader knows how you arrived at this value.

int ret;
mutex_lock(&dp->lock);
@@ -823,6 +824,25 @@ static int cdn_dp_audio_hw_params(struct device *dev, void *data,
goto out;
}
+ memset(buffer, 0, sizeof(buffer));
+
+ ret = hdmi_audio_infoframe_pack(&params->cea, buffer, sizeof(buffer));
+ if (ret < 0) {
+ DRM_DEV_ERROR(dev, "Failed to pack audio infoframe: %d\n", ret);
+ goto out;
+ }
+
+ /*
+ * Change the infoframe header to SDP header per DP 1.3 spec, Table
+ * 2-98.
+ */
+ buffer[0] = 0;
+ buffer[1] = HDMI_INFOFRAME_TYPE_AUDIO;
+ buffer[2] = 0x1b;
+ buffer[3] = 0x48;
Instead of doing this, consider splitting up hdmi_audio_infoframe_pack into
hdmi_audio_infoframe_pack and hdmi_audio_infoframe_pack_payload. The first
function does everything, while the second just packs the payload, then you can
set the SDP header independently.

+
+ cdn_dp_sdp_write(dp, 0, buffer, sizeof(buffer));
+
ret = cdn_dp_audio_config(dp, &audio);
if (!ret)
dp->audio_info = audio;
diff --git a/drivers/gpu/drm/rockchip/cdn-dp-reg.c b/drivers/gpu/drm/rockchip/cdn-dp-reg.c
index b14d211..8907db0 100644
--- a/drivers/gpu/drm/rockchip/cdn-dp-reg.c
+++ b/drivers/gpu/drm/rockchip/cdn-dp-reg.c
@@ -951,6 +951,25 @@ static void cdn_dp_audio_config_spdif(struct cdn_dp_device *dp)
clk_set_rate(dp->spdif_clk, CDN_DP_SPDIF_CLK);
}
+void cdn_dp_sdp_write(struct cdn_dp_device *dp, int entry_id, u8 *buf, u32 len)
+{
+ int idx;
+ u32 *packet = (u32 *)buf;
+ u32 length = len / 4;
length and len are pretty terrible names, it would be quite easy to use the
wrong one. Consider more descriptive names (ie: buf_len and num_packets).

+ u8 type = buf[1];
Check for len < 0?

+
+ for (idx = 0; idx < length; idx++)
+ writel(cpu_to_le32(*packet++), dp->regs + SOURCE_PIF_DATA_WR);
+
+ writel(entry_id, dp->regs + SOURCE_PIF_WR_ADDR);
+
+ writel(F_HOST_WR, dp->regs + SOURCE_PIF_WR_REQ);
+
+ writel(PIF_PKT_TYPE_VALID | F_PACKET_TYPE(type) | entry_id,
+ dp->regs + SOURCE_PIF_PKT_ALLOC_REG);
+ writel(PIF_PKT_ALLOC_WR_EN, dp->regs + SOURCE_PIF_PKT_ALLOC_WR_EN);
+}
+
int cdn_dp_audio_config(struct cdn_dp_device *dp, struct audio_info *audio)
{
int ret;
diff --git a/drivers/gpu/drm/rockchip/cdn-dp-reg.h b/drivers/gpu/drm/rockchip/cdn-dp-reg.h
index c4bbb4a83..6ec0e81 100644
--- a/drivers/gpu/drm/rockchip/cdn-dp-reg.h
+++ b/drivers/gpu/drm/rockchip/cdn-dp-reg.h
@@ -424,6 +424,11 @@
/* Reference cycles when using lane clock as reference */
#define LANE_REF_CYC 0x8000
+#define F_HOST_WR BIT(0)
+#define PIF_PKT_ALLOC_WR_EN BIT(0)
+#define PIF_PKT_TYPE_VALID (3 << 16)
+#define F_PACKET_TYPE(x) (((x) & 0xff) << 8)
Can you tuck these #defines under the definition of SOURCE_PIF_PKT_ALLOC_REG, so
we know which register they apply to?


Considering the existing code style of this file, can we keep these defines here?

+
enum voltage_swing_level {
VOLTAGE_LEVEL_0,
VOLTAGE_LEVEL_1,
@@ -478,5 +483,6 @@ int cdn_dp_set_video_status(struct cdn_dp_device *dp, int active);
int cdn_dp_config_video(struct cdn_dp_device *dp);
int cdn_dp_audio_stop(struct cdn_dp_device *dp, struct audio_info *audio);
int cdn_dp_audio_mute(struct cdn_dp_device *dp, bool enable);
+void cdn_dp_sdp_write(struct cdn_dp_device *dp, int entry_id, u8 *buf, u32 len);
int cdn_dp_audio_config(struct cdn_dp_device *dp, struct audio_info *audio);
#endif /* _CDN_DP_REG_H */
--
2.6.3


--
Chris Zhong