Subject: Re: [PATCH] drm/rockchip: cdn-dp: send audio infoframe to sink
To: Sean Paul <seanpaul@chromium.org>
Cc: linux-rockchip@lists.infradead.org, dianders@chromium.org,
        briannorris@chromium.org, Mark Yao <mark.yao@rock-chips.com>,
        David Airlie <airlied@linux.ie>, Heiko Stuebner <heiko@sntech.de>,
        dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org
References: <1500116418-4178-1-git-send-email-zyw@rock-chips.com>
 <20170717202300.c2r7ypclqbwvqbzq@art_vandelay>
From: Chris Zhong <zyw@rock-chips.com>
Message-ID: <e926d902-ceb9-4189-7ad7-ce95f134c3a6@rock-chips.com>
Date: Tue, 18 Jul 2017 19:36:13 +0800
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101
 Thunderbird/52.2.1
MIME-Version: 1.0
In-Reply-To: <20170717202300.c2r7ypclqbwvqbzq@art_vandelay>
Content-Type: text/plain; charset=gb18030; format=flowed
Content-Transfer-Encoding: 7bit
Content-Language: en-GB
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 5025
Lines: 143

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@rock-chips.com>
> 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