[PATCH 20/20] drm/i915: write AVI infoframes for LSPCON

Sharma, Shashank shashank.sharma at intel.com
Thu Jul 13 13:10:36 UTC 2017


Regards

Shashank


On 7/13/2017 6:25 PM, Ville Syrjälä wrote:
> On Thu, Jul 13, 2017 at 06:09:53PM +0530, Sharma, Shashank wrote:
>> Regards
>>
>> Shashank
>>
>>
>> On 7/13/2017 5:57 PM, Ville Syrjälä wrote:
>>> On Thu, Jul 13, 2017 at 11:11:53AM +0530, Sharma, Shashank wrote:
>>>> Regards
>>>>
>>>> Shashank
>>>>
>>>>
>>>> On 7/12/2017 10:54 PM, Ville Syrjälä wrote:
>>>>> On Mon, Jul 10, 2017 at 04:48:48PM +0530, Shashank Sharma wrote:
>>>>>> LSPCON chips can't pick the HDMI AVI infoframes from direct link.
>>>>>> In order to pass AVI infoframes from display controller to LSPCON,
>>>>>> we have to write infoframe packets into vendor specified AUX address.
>>>>>>
>>>>>> Also, LSPCON vendors provide AUX offsets, to inform the LSPCON
>>>>>> chip that the AVI IF packets are written, so that the firmware
>>>>>> can pick it up and apply.
>>>>>>
>>>>>> This patch adds function to write AVI infoframes for both MCA as
>>>>>> well as Parade Tech LSPCON chips. These two vendors provide different
>>>>>> methods for writing infoframes, so this patch contains two different
>>>>>> functions, one for each.
>>>>> Seems to me that we should also be checking the receiver cap for the
>>>>> 444->420 conversion support, and enable it in the PROTOCOL_CONVERTER
>>>>> DPCD register. Or are these LSPCON things even ignoring that part of the
>>>>> spec?
>>>> Yes, LSPCON just needs the YCBCR444 input, and info frames for 420, and
>>>> it would take care of
>>>> 444->420 conversion in FW.
>>> So it snoops the AVI infoframe we write to it to figure out that it has
>>> to do the 444->420 downsampling?
>> Yes, that's exactly what it does.
> Can you add a comment somewhere appropriate to make that clear.
> Otherwise people might wonder why we're not enabling the downsampling at
> all.
>
> Does LSPCON then not even implement the PROTOCOL_CONVERTER DCPD
> registers?
>
> Can you send the spec for this stuff my way? What I have now doesn't
> document any DPCD registers.
Actually I also don't have a document/spec which describes this. This is 
kind of knowledge sharing from people who
had design discussions with MCA/PARADE vendors on how to implement 
LSPCON specs and features.
Typically LSPCON firmware parses the AVI IF packets, and does the 
scaling down from 444->420. That's why
we are writing the AVI IF at custom AUX location.

I have added this description in patch 18's text, which talks about the 
steps to get a YCBCR420 output from LSPCON.
It says:

LSPCON chips support YCBCR420 outputs. To be able to get
YCBCR420 output from LSPCON chip, the source should:
- Generate YCBCR444 HDMI output
- Set AVI infoframes for a YCBCR420 output.

And added this small comment in 420_config:
+ /* LSPCON doesn't need scaler for YCBCR420 output */
+ if (config->lspcon_active)
+ return true;
+

But probably I should discreetly mention that LSPCON doesn't need a scalar somehow.

- Shashank

>> - Shashank
>>>> Also, its a part of LSPCON specs, that it has
>>>> to have 420 output capability.
>>>>
>>>> - Shashank
>>>>>> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
>>>>>> Cc: Imre Deak <imre.deak at intel.com>
>>>>>> Signed-off-by: Shashank Sharma <shashank.sharma at intel.com>
>>>>>> ---
>>>>>>     drivers/gpu/drm/i915/intel_ddi.c    |   8 ++
>>>>>>     drivers/gpu/drm/i915/intel_drv.h    |   3 +
>>>>>>     drivers/gpu/drm/i915/intel_lspcon.c | 174 ++++++++++++++++++++++++++++++++++++
>>>>>>     3 files changed, 185 insertions(+)
>>>>>>
>>>>>> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
>>>>>> index f691710..944d9d5 100644
>>>>>> --- a/drivers/gpu/drm/i915/intel_ddi.c
>>>>>> +++ b/drivers/gpu/drm/i915/intel_ddi.c
>>>>>> @@ -2068,6 +2068,14 @@ void intel_ddi_set_avi_infoframe(struct drm_encoder *encoder,
>>>>>>     					   rgb_qrange_limited,
>>>>>>     					   rgb_qrange_selectable);
>>>>>>     
>>>>>> +	if (crtc_state->lspcon_active) {
>>>>>> +		struct intel_lspcon *lspcon = enc_to_intel_lspcon(encoder);
>>>>>> +
>>>>>> +		/* LSPCON writes infoframes via AUX */
>>>>>> +		lspcon->write_infoframe(encoder, crtc_state, &frame);
>>>>>> +		return;
>>>>>> +	}
>>>>>> +
>>>>>>     	intel_write_infoframe(encoder, crtc_state, &frame);
>>>>>>     }
>>>>>>     
>>>>>> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
>>>>>> index fad9a53..3e686d2 100644
>>>>>> --- a/drivers/gpu/drm/i915/intel_drv.h
>>>>>> +++ b/drivers/gpu/drm/i915/intel_drv.h
>>>>>> @@ -1079,6 +1079,9 @@ struct intel_lspcon {
>>>>>>     	/* AVI IF setup function for LSPCON */
>>>>>>     	void (*set_infoframes)(struct drm_encoder *encoder,
>>>>>>     				const struct intel_crtc_state *crtc_state);
>>>>>> +	void (*write_infoframe)(struct drm_encoder *encoder,
>>>>>> +				const struct intel_crtc_state *crtc_state,
>>>>>> +				union hdmi_infoframe *frame);
>>>>>>     };
>>>>>>     
>>>>>>     struct intel_digital_port {
>>>>>> diff --git a/drivers/gpu/drm/i915/intel_lspcon.c b/drivers/gpu/drm/i915/intel_lspcon.c
>>>>>> index 53ddd39..01fddf7 100644
>>>>>> --- a/drivers/gpu/drm/i915/intel_lspcon.c
>>>>>> +++ b/drivers/gpu/drm/i915/intel_lspcon.c
>>>>>> @@ -31,6 +31,18 @@
>>>>>>     #define LSPCON_VENDOR_PARADE_OUI 0x001CF8
>>>>>>     #define LSPCON_VENDOR_MCA_OUI 0x0060AD
>>>>>>     
>>>>>> +/* AUX addresses to write AVI IF into */
>>>>>> +#define LSPCON_MCA_AVI_IF_WRITE_OFFSET 0x5C0
>>>>>> +#define LSPCON_MCA_AVI_IF_CTRL 0x5DF
>>>>>> +#define  LSPCON_MCA_AVI_IF_KICKOFF (1 << 0)
>>>>>> +#define  LSPCON_MCA_AVI_IF_HANDLED (1 << 1)
>>>>>> +
>>>>>> +#define LSPCON_PARADE_AVI_IF_WRITE_OFFSET 0x516
>>>>>> +#define LSPCON_PARADE_AVI_IF_CTRL 0x51E
>>>>>> +#define  LSPCON_PARADE_AVI_IF_KICKOFF (1 << 7)
>>>>>> +#define LSPCON_PARADE_AVI_IF_STATUS 0x51F
>>>>>> +#define  LSPCON_PARADE_AVI_IF_HANDLED (2 << 6)
>>>>>> +
>>>>>>     static struct intel_dp *lspcon_to_intel_dp(struct intel_lspcon *lspcon)
>>>>>>     {
>>>>>>     	struct intel_digital_port *dig_port =
>>>>>> @@ -217,6 +229,167 @@ bool lspcon_ycbcr420_config(struct drm_connector *connector,
>>>>>>     	return false;
>>>>>>     }
>>>>>>     
>>>>>> +static bool _lspcon_write_infoframe_parade(struct drm_dp_aux *aux,
>>>>>> +					   uint8_t *buffer, ssize_t len)
>>>>>> +{
>>>>>> +	u8 avi_if_ctrl;
>>>>>> +	u8 avi_if_status;
>>>>>> +	u8 count = 0;
>>>>>> +	u8 retry = 5;
>>>>>> +	u8 avi_buf[8] = {0, };
>>>>>> +	uint16_t reg;
>>>>>> +	ssize_t ret;
>>>>>> +
>>>>>> +	while (count++ < 4) {
>>>>>> +
>>>>>> +		do {
>>>>>> +			/* Is LSPCON FW ready */
>>>>>> +			reg = LSPCON_PARADE_AVI_IF_CTRL;
>>>>>> +			ret = drm_dp_dpcd_read(aux, reg, &avi_if_ctrl, 1);
>>>>>> +			if (ret < 0) {
>>>>>> +				DRM_ERROR("DPCD read failed, add:0x%x\n", reg);
>>>>>> +				return false;
>>>>>> +			}
>>>>>> +
>>>>>> +			if (avi_if_ctrl & LSPCON_PARADE_AVI_IF_KICKOFF)
>>>>>> +				break;
>>>>>> +			usleep_range(100, 200);
>>>>>> +		} while (--retry);
>>>>>> +
>>>>>> +		if (!(avi_if_ctrl & LSPCON_PARADE_AVI_IF_KICKOFF)) {
>>>>>> +			DRM_ERROR("LSPCON FW not ready for infoframes\n");
>>>>>> +			return false;
>>>>>> +		}
>>>>>> +
>>>>>> +		/*
>>>>>> +		 * AVI Infoframe contains 31 bytes of data:
>>>>>> +		 *	HB0 to HB2   (3 bytes header)
>>>>>> +		 *	PB0 to PB27 (28 bytes data)
>>>>>> +		 * As per Parade spec, while sending first block (8bytes),
>>>>>> +		 * byte 0 is kept for request token no, and byte1 - byte7
>>>>>> +		 * contain frame data. So we have to pack frame like this:
>>>>>> +		 *	first block of 8 bytes: <token> <HB0-HB2> <PB0-PB3>
>>>>>> +		 *	next 3 blocks: <PB4-PB27>
>>>>>> +		 */
>>>>>> +		if (count)
>>>>>> +			memcpy(avi_buf, buffer + count * 8 - 1, 8);
>>>>>> +		else {
>>>>>> +			avi_buf[0] = 1;
>>>>>> +			memcpy(&avi_buf[1], buffer, 7);
>>>>>> +		}
>>>>>> +
>>>>>> +		/* Write 8 bytes of data at a time */
>>>>>> +		reg = LSPCON_PARADE_AVI_IF_WRITE_OFFSET;
>>>>>> +		ret = drm_dp_dpcd_write(aux, reg, avi_buf, 8);
>>>>>> +		if (ret < 0) {
>>>>>> +			DRM_ERROR("DPCD write failed, add:0x%x\n", reg);
>>>>>> +			return false;
>>>>>> +		}
>>>>>> +
>>>>>> +		/*
>>>>>> +		 * While sending a block of 8 byes, we need to inform block
>>>>>> +		 * number to FW, by programming bits[1:0] of ctrl reg with
>>>>>> +		 * block number
>>>>>> +		 */
>>>>>> +		avi_if_ctrl = 0x80 + count;
>>>>>> +		reg = LSPCON_PARADE_AVI_IF_CTRL;
>>>>>> +		ret = drm_dp_dpcd_write(aux, reg, &avi_if_ctrl, 1);
>>>>>> +		if (ret < 0) {
>>>>>> +			DRM_ERROR("DPCD write failed, add:0x%x\n", reg);
>>>>>> +			return false;
>>>>>> +		}
>>>>>> +	}
>>>>>> +
>>>>>> +	/* Check LSPCON FW status */
>>>>>> +	reg = LSPCON_PARADE_AVI_IF_STATUS;
>>>>>> +	ret = drm_dp_dpcd_read(aux, reg, &avi_if_status, 1);
>>>>>> +	if (ret < 0) {
>>>>>> +		DRM_ERROR("DPCD write failed, address 0x%x\n", reg);
>>>>>> +		return false;
>>>>>> +	}
>>>>>> +
>>>>>> +	if (avi_if_status & LSPCON_PARADE_AVI_IF_HANDLED)
>>>>>> +		DRM_DEBUG_KMS("AVI IF handled by FW\n");
>>>>>> +
>>>>>> +	return true;
>>>>>> +}
>>>>>> +
>>>>>> +static bool _lspcon_write_infoframe_mca(struct drm_dp_aux *aux,
>>>>>> +					uint8_t *buffer, ssize_t len)
>>>>>> +{
>>>>>> +	int ret;
>>>>>> +	uint32_t val = 0;
>>>>>> +	uint16_t reg;
>>>>>> +	uint8_t *data = buffer;
>>>>>> +
>>>>>> +	reg = LSPCON_MCA_AVI_IF_WRITE_OFFSET;
>>>>>> +	while (val < len) {
>>>>>> +		ret = drm_dp_dpcd_write(aux, reg, data, 1);
>>>>>> +		if (ret < 0) {
>>>>>> +			DRM_ERROR("DPCD write failed, add:0x%x\n", reg);
>>>>>> +			return false;
>>>>>> +		}
>>>>>> +		val++; reg++; data++;
>>>>>> +	}
>>>>>> +
>>>>>> +	val = 0;
>>>>>> +	reg = LSPCON_MCA_AVI_IF_CTRL;
>>>>>> +	ret = drm_dp_dpcd_read(aux, reg, &val, 1);
>>>>>> +	if (ret < 0) {
>>>>>> +		DRM_ERROR("DPCD read failed, address 0x%x\n", reg);
>>>>>> +		return false;
>>>>>> +	}
>>>>>> +
>>>>>> +	/* Indicate LSPCON chip about infoframe, clear bit 1 and set bit 0 */
>>>>>> +	val &= ~LSPCON_MCA_AVI_IF_HANDLED;
>>>>>> +	val |= LSPCON_MCA_AVI_IF_KICKOFF;
>>>>>> +
>>>>>> +	ret = drm_dp_dpcd_write(aux, reg, &val, 1);
>>>>>> +	if (ret < 0) {
>>>>>> +		DRM_ERROR("DPCD read failed, address 0x%x\n", reg);
>>>>>> +		return false;
>>>>>> +	}
>>>>>> +
>>>>>> +	val = 0;
>>>>>> +	ret = drm_dp_dpcd_read(aux, reg, &val, 1);
>>>>>> +	if (ret < 0) {
>>>>>> +		DRM_ERROR("DPCD read failed, address 0x%x\n", reg);
>>>>>> +		return false;
>>>>>> +	}
>>>>>> +
>>>>>> +	if (val == LSPCON_MCA_AVI_IF_HANDLED)
>>>>>> +		DRM_DEBUG_KMS("AVI IF handled by FW\n");
>>>>>> +
>>>>>> +	return true;
>>>>>> +}
>>>>>> +
>>>>>> +void lspcon_write_infoframe(struct drm_encoder *encoder,
>>>>>> +				  const struct intel_crtc_state *crtc_state,
>>>>>> +				  union hdmi_infoframe *frame)
>>>>>> +{
>>>>>> +	bool ret;
>>>>>> +	ssize_t len;
>>>>>> +	uint8_t buf[VIDEO_DIP_DATA_SIZE];
>>>>>> +	struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
>>>>>> +	struct intel_lspcon *lspcon = enc_to_intel_lspcon(encoder);
>>>>>> +
>>>>>> +	len = hdmi_infoframe_pack(frame, buf, sizeof(buf));
>>>>>> +	if (len < 0) {
>>>>>> +		DRM_ERROR("Failed to pack AVI IF\n");
>>>>>> +		return;
>>>>>> +	}
>>>>>> +
>>>>>> +	if (lspcon->vendor == LSPCON_VENDOR_MCA)
>>>>>> +		ret = _lspcon_write_infoframe_mca(&intel_dp->aux, buf, len);
>>>>>> +	else
>>>>>> +		ret = _lspcon_write_infoframe_parade(&intel_dp->aux, buf, len);
>>>>>> +
>>>>>> +	if (!ret)
>>>>>> +		DRM_ERROR("Failed to write AVI infoframes\n");
>>>>>> +	else
>>>>>> +		DRM_DEBUG_DRIVER("AVI infoframes updated successfully\n");
>>>>>> +}
>>>>>> +
>>>>>>     void lspcon_resume(struct intel_lspcon *lspcon)
>>>>>>     {
>>>>>>     	enum drm_lspcon_mode expected_mode;
>>>>>> @@ -282,6 +455,7 @@ bool lspcon_init(struct intel_digital_port *intel_dig_port)
>>>>>>     
>>>>>>     	connector->ycbcr_420_allowed = true;
>>>>>>     	lspcon->set_infoframes = intel_ddi_set_avi_infoframe;
>>>>>> +	lspcon->write_infoframe = lspcon_write_infoframe;
>>>>>>     	drm_dp_read_desc(&dp->aux, &dp->desc, drm_dp_is_branch(dp->dpcd));
>>>>>>     
>>>>>>     	DRM_DEBUG_KMS("Success: LSPCON init\n");
>>>>>> -- 
>>>>>> 2.7.4

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