[PATCHv2 12/56] drm/omap: dsi: simplify read functions

[Laurent Pinchart]

Hi Sebastian,

Thank you for the patch.

On Tue, Feb 25, 2020 at 12:20:42AM +0100, Sebastian Reichel wrote:
> Simplify the read related message handling by using the functionality
> provided by CONFIG_DRM_MIPI_DSI.
> 
> Signed-off-by: Sebastian Reichel <sebastian.reichel at collabora.com>
> ---
>  drivers/gpu/drm/omapdrm/dss/dsi.c | 109 +++++++++---------------------
>  1 file changed, 33 insertions(+), 76 deletions(-)
> 
> diff --git a/drivers/gpu/drm/omapdrm/dss/dsi.c b/drivers/gpu/drm/omapdrm/dss/dsi.c
> index e5589e615808..9b5b078beb6d 100644
> --- a/drivers/gpu/drm/omapdrm/dss/dsi.c
> +++ b/drivers/gpu/drm/omapdrm/dss/dsi.c
> @@ -2741,60 +2741,6 @@ static int dsi_vc_write_common(struct omap_dss_device *dssdev,
>  	return 0;
>  }
>  
> -static int dsi_vc_dcs_send_read_request(struct dsi_data *dsi, int channel,
> -					u8 dcs_cmd)
> -{
> -	int r;
> -
> -	if (dsi->debug_read)
> -		DSSDBG("dsi_vc_dcs_send_read_request(ch%d, dcs_cmd %x)\n",
> -			channel, dcs_cmd);
> -

Do you plan to drop debug_read ? I don't really mind, but it can have
its uses. If this wasn't done on purpose, you may want to move those
messages to dsi_vc_dcs_read() and dsi_vc_generic_read().

> -	r = dsi_vc_send_short(dsi, channel, MIPI_DSI_DCS_READ, dcs_cmd, 0);
> -	if (r) {
> -		DSSERR("dsi_vc_dcs_send_read_request(ch %d, cmd 0x%02x)"
> -			" failed\n", channel, dcs_cmd);
> -		return r;
> -	}
> -
> -	return 0;
> -}
> -
> -static int dsi_vc_generic_send_read_request(struct dsi_data *dsi, int channel,
> -					    const u8 *reqdata, int reqlen)
> -{
> -	u16 data;
> -	u8 data_type;
> -	int r;
> -
> -	if (dsi->debug_read)
> -		DSSDBG("dsi_vc_generic_send_read_request(ch %d, reqlen %d)\n",
> -			channel, reqlen);
> -
> -	if (reqlen == 0) {
> -		data_type = MIPI_DSI_GENERIC_READ_REQUEST_0_PARAM;
> -		data = 0;
> -	} else if (reqlen == 1) {
> -		data_type = MIPI_DSI_GENERIC_READ_REQUEST_1_PARAM;
> -		data = reqdata[0];
> -	} else if (reqlen == 2) {
> -		data_type = MIPI_DSI_GENERIC_READ_REQUEST_2_PARAM;
> -		data = reqdata[0] | (reqdata[1] << 8);
> -	} else {
> -		BUG();
> -		return -EINVAL;
> -	}
> -
> -	r = dsi_vc_send_short(dsi, channel, data_type, data, 0);
> -	if (r) {
> -		DSSERR("dsi_vc_generic_send_read_request(ch %d, reqlen %d)"
> -			" failed\n", channel, reqlen);
> -		return r;
> -	}
> -
> -	return 0;
> -}
> -
>  static int dsi_vc_read_rx_fifo(struct dsi_data *dsi, int channel, u8 *buf,
>  			       int buflen, enum dss_dsi_content_type type)
>  {
> @@ -2903,61 +2849,75 @@ static int dsi_vc_read_rx_fifo(struct dsi_data *dsi, int channel, u8 *buf,
>  	return r;
>  }
>  
> -static int dsi_vc_dcs_read(struct omap_dss_device *dssdev, int channel, u8 dcs_cmd,
> -		u8 *buf, int buflen)
> +static int dsi_vc_dcs_read(struct omap_dss_device *dssdev,
> +			   const struct mipi_dsi_msg *msg)
>  {
>  	struct dsi_data *dsi = to_dsi_data(dssdev);
>  	int r;
> +	u8 dcs_cmd = ((u8*) msg->tx_buf)[0];

Nitpicking, dcs_cmd before r ?

>  
> -	r = dsi_vc_dcs_send_read_request(dsi, channel, dcs_cmd);
> +	r = dsi_vc_send_short(dsi, msg->channel, MIPI_DSI_DCS_READ, dcs_cmd, 0);
>  	if (r)
>  		goto err;
>  
> -	r = dsi_vc_send_bta_sync(dssdev, channel);
> +	r = dsi_vc_send_bta_sync(dssdev, msg->channel);
>  	if (r)
>  		goto err;
>  
> -	r = dsi_vc_read_rx_fifo(dsi, channel, buf, buflen,
> +	r = dsi_vc_read_rx_fifo(dsi, msg->channel, msg->rx_buf, msg->rx_len,
>  		DSS_DSI_CONTENT_DCS);
>  	if (r < 0)
>  		goto err;
>  
> -	if (r != buflen) {
> +	if (r != msg->rx_len) {
>  		r = -EIO;
>  		goto err;
>  	}
>  
>  	return 0;
>  err:
> -	DSSERR("dsi_vc_dcs_read(ch %d, cmd 0x%02x) failed\n", channel, dcs_cmd);
> +	DSSERR("dsi_vc_dcs_read(ch %d, cmd 0x%02x) failed\n",
> +		msg->channel, dcs_cmd);
>  	return r;
>  }
>  
> -static int dsi_vc_generic_read(struct omap_dss_device *dssdev, int channel,
> -		const u8 *reqdata, int reqlen, u8 *buf, int buflen)
> +static int dsi_vc_generic_read(struct omap_dss_device *dssdev,
> +			       const struct mipi_dsi_msg *msg)
>  {
>  	struct dsi_data *dsi = to_dsi_data(dssdev);
> +	struct mipi_dsi_packet packet;
> +	u16 data;
>  	int r;
>  
> -	r = dsi_vc_generic_send_read_request(dsi, channel, reqdata, reqlen);
> +	r = mipi_dsi_create_packet(&packet, msg);
> +	if (r < 0)
> +		goto err;
> +
> +	data = packet.header[1] | (packet.header[2] << 8);

As with the previous patch, I think you can compute data manually if the
only use of the packet structure is to get this information.

> +
> +	r = dsi_vc_send_short(dsi, msg->channel, msg->type, data, 0);
>  	if (r)
> -		return r;
> +		goto err;
>  
> -	r = dsi_vc_send_bta_sync(dssdev, channel);
> +	r = dsi_vc_send_bta_sync(dssdev, msg->channel);
>  	if (r)
> -		return r;
> +		goto err;
>  
> -	r = dsi_vc_read_rx_fifo(dsi, channel, buf, buflen,
> +	r = dsi_vc_read_rx_fifo(dsi, msg->channel, msg->rx_buf, msg->rx_len,
>  		DSS_DSI_CONTENT_GENERIC);
>  	if (r < 0)
> -		return r;
> +		goto err;
>  
> -	if (r != buflen) {
> +	if (r != msg->rx_len) {
>  		r = -EIO;
> -		return r;
> +		goto err;
>  	}
>  
>  	return 0;
> +err:
> +	DSSERR("dsi_vc_generic_read(ch %d, reqlen %d) failed\n",
> +		msg->channel, msg->tx_len);
> +	return r;
>  }
>  
>  static int dsi_enter_ulps(struct dsi_data *dsi)
> @@ -4768,12 +4728,9 @@ static ssize_t omap_dsi_transfer(struct omap_dss_device *dssdev,
>  	case MIPI_DSI_GENERIC_READ_REQUEST_0_PARAM:
>  	case MIPI_DSI_GENERIC_READ_REQUEST_1_PARAM:
>  	case MIPI_DSI_GENERIC_READ_REQUEST_2_PARAM:
> -		return dsi_vc_generic_read(dssdev, msg->channel, msg->tx_buf,
> -				msg->tx_len, msg->rx_buf, msg->rx_len);
> +		return dsi_vc_generic_read(dssdev, msg);
>  	case MIPI_DSI_DCS_READ:
> -		return dsi_vc_dcs_read(dssdev, msg->channel,
> -				((u8*) msg->tx_buf)[0],
> -				msg->rx_buf, msg->rx_len);
> +		return dsi_vc_dcs_read(dssdev, msg);
>  	}
>  
>  	return -EINVAL;

-- 
Regards,

Laurent Pinchart