Re: [PATCH v3 10/56] drm/omap: dsi: simplify write function

Laurent Pinchart
2020-11-09T08:21:41Z

Hi Tomi and Sebastian,

Thank you for the patch.

On Thu, Nov 05, 2020 at 02:02:47PM +0200, Tomi Valkeinen wrote:
> From: Sebastian Reichel <sebastian.reichel@collabora.com>
>
> Simplify the write related messages handling by using the functionality
> provided by CONFIG_DRM_MIPI_DSI.
>
> Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
> ---
> drivers/gpu/drm/omapdrm/dss/Kconfig | 1 +
> drivers/gpu/drm/omapdrm/dss/dsi.c | 146 +++++++---------------------
> 2 files changed, 34 insertions(+), 113 deletions(-)
>
> diff --git a/drivers/gpu/drm/omapdrm/dss/Kconfig b/drivers/gpu/drm/omapdrm/dss/Kconfig
> index 2658c521b702..fd7dfa28ce97 100644
> --- a/drivers/gpu/drm/omapdrm/dss/Kconfig
> +++ b/drivers/gpu/drm/omapdrm/dss/Kconfig
> @@ -95,6 +95,7 @@ config OMAP2_DSS_SDI
> config OMAP2_DSS_DSI
> bool "DSI support"
> default n
> + select DRM_MIPI_DSI
> help
> MIPI DSI (Display Serial Interface) support.
>
> diff --git a/drivers/gpu/drm/omapdrm/dss/dsi.c b/drivers/gpu/drm/omapdrm/dss/dsi.c
> index 348be32505a2..e1595c0608f2 100644
> --- a/drivers/gpu/drm/omapdrm/dss/dsi.c
> +++ b/drivers/gpu/drm/omapdrm/dss/dsi.c
> @@ -2696,97 +2696,50 @@ static int dsi_vc_send_null(struct dsi_data *dsi, int channel)
> return dsi_vc_send_long(dsi, channel, MIPI_DSI_NULL_PACKET, NULL, 0, 0);
> }
>
> -static int dsi_vc_write_nosync_common(struct dsi_data *dsi, int channel,
> - const u8 *data, int len,
> - enum dss_dsi_content_type type)
> -{
> - int r;
> -
> - if (len == 0) {
> - BUG_ON(type == DSS_DSI_CONTENT_DCS);
> - r = dsi_vc_send_short(dsi, channel,
> - MIPI_DSI_GENERIC_SHORT_WRITE_0_PARAM, 0, 0);
> - } else if (len == 1) {
> - r = dsi_vc_send_short(dsi, channel,
> - type == DSS_DSI_CONTENT_GENERIC ?
> - MIPI_DSI_GENERIC_SHORT_WRITE_1_PARAM :
> - MIPI_DSI_DCS_SHORT_WRITE, data[0], 0);
> - } else if (len == 2) {
> - r = dsi_vc_send_short(dsi, channel,
> - type == DSS_DSI_CONTENT_GENERIC ?
> - MIPI_DSI_GENERIC_SHORT_WRITE_2_PARAM :
> - MIPI_DSI_DCS_SHORT_WRITE_PARAM,
> - data[0] | (data[1] << 8), 0);
> - } else {
> - r = dsi_vc_send_long(dsi, channel,
> - type == DSS_DSI_CONTENT_GENERIC ?
> - MIPI_DSI_GENERIC_LONG_WRITE :
> - MIPI_DSI_DCS_LONG_WRITE, data, len, 0);
> - }
> -
> - return r;
> -}
> -
> -static int dsi_vc_dcs_write_nosync(struct omap_dss_device *dssdev, int channel,
> - const u8 *data, int len)
> +static int dsi_vc_write_common(struct omap_dss_device *dssdev,
> + const struct mipi_dsi_msg *msg)
> {
> struct dsi_data *dsi = to_dsi_data(dssdev);
> + struct mipi_dsi_packet packet;
> + int r;
>
> - return dsi_vc_write_nosync_common(dsi, channel, data, len,
> - DSS_DSI_CONTENT_DCS);
> -}
> + r = mipi_dsi_create_packet(&packet, msg);
> + if (r < 0)
> + return r;
>
> -static int dsi_vc_generic_write_nosync(struct omap_dss_device *dssdev, int channel,
> - const u8 *data, int len)
> -{
> - struct dsi_data *dsi = to_dsi_data(dssdev);
> + if (mipi_dsi_packet_format_is_short(msg->type)) {
> + u16 data = packet.header[1] | (packet.header[2] << 8);

packet is only used here, should the variable and
mipi_dsi_create_packet() call be moved to this branch of the if ? Feel
free to ignore if a patch further down the series makes use of packet in
different locations.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

>
> - return dsi_vc_write_nosync_common(dsi, channel, data, len,
> - DSS_DSI_CONTENT_GENERIC);
> -}
> + r = dsi_vc_send_short(dsi, msg->channel, msg->type, data, 0);
> + } else {
> + r = dsi_vc_send_long(dsi, msg->channel, msg->type,
> + msg->tx_buf, msg->tx_len, 0);
> + }
>
> -static int dsi_vc_write_common(struct omap_dss_device *dssdev,
> - int channel, const u8 *data, int len,
> - enum dss_dsi_content_type type)
> -{
> - struct dsi_data *dsi = to_dsi_data(dssdev);
> - int r;
> + if (r < 0)
> + return r;
>
> - r = dsi_vc_write_nosync_common(dsi, channel, data, len, type);
> - if (r)
> - goto err;
> + /*
> + * TODO: we do not always have to do the BTA sync, for example
> + * we can improve performance by setting the update window
> + * information without sending BTA sync between the commands.
> + * In that case we can return early.
> + */
>
> - r = dsi_vc_send_bta_sync(dssdev, channel);
> - if (r)
> - goto err;
> + r = dsi_vc_send_bta_sync(dssdev, msg->channel);
> + if (r) {
> + DSSERR("bta sync failed\n");
> + return r;
> + }
>
> /* RX_FIFO_NOT_EMPTY */
> - if (REG_GET(dsi, DSI_VC_CTRL(channel), 20, 20)) {
> + if (REG_GET(dsi, DSI_VC_CTRL(msg->channel), 20, 20)) {
> DSSERR("rx fifo not empty after write, dumping data:\n");
> - dsi_vc_flush_receive_data(dsi, channel);
> - r = -EIO;
> - goto err;
> + dsi_vc_flush_receive_data(dsi, msg->channel);
> + return -EIO;
> }
>
> return 0;
> -err:
> - DSSERR("dsi_vc_write_common(ch %d, cmd 0x%02x, len %d) failed\n",
> - channel, data[0], len);
> - return r;
> -}
> -
> -static int dsi_vc_dcs_write(struct omap_dss_device *dssdev, int channel,
> - const u8 *data, int len)
> -{
> - return dsi_vc_write_common(dssdev, channel, data, len,
> - DSS_DSI_CONTENT_DCS);
> -}
> -
> -static int dsi_vc_generic_write(struct omap_dss_device *dssdev, int channel,
> - const u8 *data, int len)
> -{
> - return dsi_vc_write_common(dssdev, channel, data, len,
> - DSS_DSI_CONTENT_GENERIC);
> }
>
> static int dsi_vc_dcs_send_read_request(struct dsi_data *dsi, int channel,
> @@ -3008,15 +2961,6 @@ static int dsi_vc_generic_read(struct omap_dss_device *dssdev, int channel,
> return 0;
> }
>
> -static int dsi_vc_set_max_rx_packet_size(struct omap_dss_device *dssdev, int channel,
> - u16 len)
> -{
> - struct dsi_data *dsi = to_dsi_data(dssdev);
> -
> - return dsi_vc_send_short(dsi, channel,
> - MIPI_DSI_SET_MAXIMUM_RETURN_PACKET_SIZE, len, 0);
> -}
> -
> static int dsi_enter_ulps(struct dsi_data *dsi)
> {
> DECLARE_COMPLETION_ONSTACK(completion);
> @@ -4817,36 +4761,17 @@ static void dsi_release_vc(struct omap_dss_device *dssdev, int channel)
> static ssize_t omap_dsi_transfer(struct omap_dss_device *dssdev,
> const struct mipi_dsi_msg *msg)
> {
> - /*
> - * no_sync can be used to optimize performance by sending e.g. column
> - * and page information without syncing in between. It's not absolutley
> - * required, so postpone this feature for now.
> - */
> - bool no_sync = false;
> - u16 val;
> -
> switch (msg->type) {
> case MIPI_DSI_GENERIC_SHORT_WRITE_0_PARAM:
> case MIPI_DSI_GENERIC_SHORT_WRITE_1_PARAM:
> case MIPI_DSI_GENERIC_SHORT_WRITE_2_PARAM:
> case MIPI_DSI_GENERIC_LONG_WRITE:
> - if (no_sync)
> - return dsi_vc_generic_write_nosync(dssdev, msg->channel,
> - msg->tx_buf,
> - msg->tx_len);
> - else
> - return dsi_vc_generic_write(dssdev, msg->channel,
> - msg->tx_buf, msg->tx_len);
> case MIPI_DSI_DCS_SHORT_WRITE:
> case MIPI_DSI_DCS_SHORT_WRITE_PARAM:
> case MIPI_DSI_DCS_LONG_WRITE:
> - if (no_sync)
> - return dsi_vc_dcs_write_nosync(dssdev, msg->channel,
> - msg->tx_buf,
> - msg->tx_len);
> - else
> - return dsi_vc_dcs_write(dssdev, msg->channel,
> - msg->tx_buf, msg->tx_len);
> + case MIPI_DSI_SET_MAXIMUM_RETURN_PACKET_SIZE:
> + case MIPI_DSI_NULL_PACKET:
> + return dsi_vc_write_common(dssdev, msg);
> case MIPI_DSI_GENERIC_READ_REQUEST_0_PARAM:
> case MIPI_DSI_GENERIC_READ_REQUEST_1_PARAM:
> case MIPI_DSI_GENERIC_READ_REQUEST_2_PARAM:
> @@ -4857,11 +4782,6 @@ static ssize_t omap_dsi_transfer(struct omap_dss_device *dssdev,
> return dsi_vc_dcs_read(dssdev, msg->channel,
> ((u8 *)msg->tx_buf)[0],
> msg->rx_buf, msg->rx_len);
> - case MIPI_DSI_SET_MAXIMUM_RETURN_PACKET_SIZE:
> - val = le16_to_cpu(*((__le16 *)msg->tx_buf));
> - return dsi_vc_set_max_rx_packet_size(dssdev, msg->channel, val);
> - case MIPI_DSI_NULL_PACKET:
> - return dsi_vc_send_null(to_dsi_data(dssdev), msg->channel);
> }
>
> return -EINVAL;

--
Regards,

Laurent Pinchart