Re: [PATCH v5 6/9] drm/bridge: cdns: Separate DSI and D-PHY configuration

Paul Kocialkowski
2019-02-07T08:45:06Z

Hi,

On Mon, 2019-01-21 at 16:45 +0100, Maxime Ripard wrote:
> The current configuration of the DSI bridge and its associated D-PHY is
> intertwined. In order to ease the future conversion to the phy framework
> for the D-PHY part, let's split the configuration in two.

See below about a silly mistake when refactoring. Looks good otherwise,
so with that fixed:

Reviewed-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>

> Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
> ---
> drivers/gpu/drm/bridge/cdns-dsi.c | 101 ++++++++++++++++++++++---------
> 1 file changed, 73 insertions(+), 28 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/cdns-dsi.c b/drivers/gpu/drm/bridge/cdns-dsi.c
> index ce9496d13986..796874e76308 100644
> --- a/drivers/gpu/drm/bridge/cdns-dsi.c
> +++ b/drivers/gpu/drm/bridge/cdns-dsi.c
> @@ -545,6 +545,15 @@ bridge_to_cdns_dsi_input(struct drm_bridge *bridge)
> return container_of(bridge, struct cdns_dsi_input, bridge);
> }
>
> +static unsigned int mode_to_dpi_hfp(const struct drm_display_mode *mode,
> + bool mode_valid_check)
> +{
> + if (mode_valid_check)
> + return mode->hsync_start - mode->hdisplay;
> +
> + return mode->crtc_hsync_start - mode->crtc_hdisplay;
> +}
> +
> static int cdns_dsi_get_dphy_pll_cfg(struct cdns_dphy *dphy,
> struct cdns_dphy_cfg *cfg,
> unsigned int dpi_htotal,
> @@ -731,14 +740,12 @@ static unsigned int dpi_to_dsi_timing(unsigned int dpi_timing,
> static int cdns_dsi_mode2cfg(struct cdns_dsi *dsi,
> const struct drm_display_mode *mode,
> struct cdns_dsi_cfg *dsi_cfg,
> - struct cdns_dphy_cfg *dphy_cfg,
> bool mode_valid_check)
> {
> - unsigned long dsi_htotal = 0, dsi_hss_hsa_hse_hbp = 0;
> struct cdns_dsi_output *output = &dsi->output;
> - unsigned int dsi_hfp_ext = 0, dpi_hfp, tmp;
> + unsigned int tmp;
> bool sync_pulse = false;
> - int bpp, nlanes, ret;
> + int bpp, nlanes;
>
> memset(dsi_cfg, 0, sizeof(*dsi_cfg));
>
> @@ -757,8 +764,6 @@ static int cdns_dsi_mode2cfg(struct cdns_dsi *dsi,
> mode->crtc_hsync_end : mode->crtc_hsync_start);
>
> dsi_cfg->hbp = dpi_to_dsi_timing(tmp, bpp, DSI_HBP_FRAME_OVERHEAD);
> - dsi_htotal += dsi_cfg->hbp + DSI_HBP_FRAME_OVERHEAD;
> - dsi_hss_hsa_hse_hbp += dsi_cfg->hbp + DSI_HBP_FRAME_OVERHEAD;
>
> if (sync_pulse) {
> if (mode_valid_check)
> @@ -768,49 +773,91 @@ static int cdns_dsi_mode2cfg(struct cdns_dsi *dsi,
>
> dsi_cfg->hsa = dpi_to_dsi_timing(tmp, bpp,
> DSI_HSA_FRAME_OVERHEAD);
> - dsi_htotal += dsi_cfg->hsa + DSI_HSA_FRAME_OVERHEAD;
> - dsi_hss_hsa_hse_hbp += dsi_cfg->hsa + DSI_HSA_FRAME_OVERHEAD;
> }
>
> dsi_cfg->hact = dpi_to_dsi_timing(mode_valid_check ?
> mode->hdisplay : mode->crtc_hdisplay,
> bpp, 0);
> - dsi_htotal += dsi_cfg->hact;
> + dsi_cfg->hfp = dpi_to_dsi_timing(mode_to_dpi_hfp(mode, mode_valid_check),
> + bpp, DSI_HFP_FRAME_OVERHEAD);
>
> - if (mode_valid_check)
> - dpi_hfp = mode->hsync_start - mode->hdisplay;
> - else
> - dpi_hfp = mode->crtc_hsync_start - mode->crtc_hdisplay;
> + return 0;
> +}
> +
> +static int cdns_dphy_validate(struct cdns_dsi *dsi,
> + struct cdns_dsi_cfg *dsi_cfg,
> + struct cdns_dphy_cfg *dphy_cfg,
> + const struct drm_display_mode *mode,
> + bool mode_valid_check)
> +{
> + struct cdns_dsi_output *output = &dsi->output;
> + unsigned long dsi_htotal;
> + unsigned int dsi_hfp_ext = 0;
> +
> + int ret;
> +
> + dsi_htotal = dsi_cfg->hbp + DSI_HBP_FRAME_OVERHEAD;
> + if (output->dev->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)
> + dsi_htotal += dsi_cfg->hsa + DSI_HSA_FRAME_OVERHEAD;
>
> - dsi_cfg->hfp = dpi_to_dsi_timing(dpi_hfp, bpp, DSI_HFP_FRAME_OVERHEAD);
> + dsi_htotal += dsi_cfg->hact;
> dsi_htotal += dsi_cfg->hfp + DSI_HFP_FRAME_OVERHEAD;
>
> if (mode_valid_check)
> ret = cdns_dsi_get_dphy_pll_cfg(dsi->dphy, dphy_cfg,
> - mode->htotal, bpp,
> + mode->htotal,
> mode->clock * 1000,
> - dsi_htotal, nlanes,
> + mipi_dsi_pixel_format_to_bpp(output->dev->format),

The bpp argument sits between htotal and clock, this puts it after
clock which looks incorrect.

Cheers,

Paul

> + dsi_htotal,
> + output->dev->lanes,
> &dsi_hfp_ext);
> else
> ret = cdns_dsi_get_dphy_pll_cfg(dsi->dphy, dphy_cfg,
> - mode->crtc_htotal, bpp,
> + mode->crtc_htotal,
> + mipi_dsi_pixel_format_to_bpp(output->dev->format),
> mode->crtc_clock * 1000,
> - dsi_htotal, nlanes,
> + dsi_htotal,
> + output->dev->lanes,
> &dsi_hfp_ext);
> -
> if (ret)
> return ret;
>
> dsi_cfg->hfp += dsi_hfp_ext;
> - dsi_htotal += dsi_hfp_ext;
> - dsi_cfg->htotal = dsi_htotal;
> + dsi_cfg->htotal = dsi_htotal + dsi_hfp_ext;
> +
> + return 0;
> +}
> +
> +static int cdns_dsi_check_conf(struct cdns_dsi *dsi,
> + const struct drm_display_mode *mode,
> + struct cdns_dsi_cfg *dsi_cfg,
> + struct cdns_dphy_cfg *dphy_cfg,
> + bool mode_valid_check)
> +{
> + struct cdns_dsi_output *output = &dsi->output;
> + unsigned long dsi_hss_hsa_hse_hbp;
> + unsigned int nlanes = output->dev->lanes;
> + int ret;
> +
> + ret = cdns_dsi_mode2cfg(dsi, mode, dsi_cfg, mode_valid_check);
> + if (ret)
> + return ret;
> +
> + ret = cdns_dphy_validate(dsi, dsi_cfg, dphy_cfg, mode, mode_valid_check);
> + if (ret)
> + return ret;
> +
> + dsi_hss_hsa_hse_hbp = dsi_cfg->hbp + DSI_HBP_FRAME_OVERHEAD;
> + if (output->dev->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)
> + dsi_hss_hsa_hse_hbp += dsi_cfg->hsa + DSI_HSA_FRAME_OVERHEAD;
>
> /*
> * Make sure DPI(HFP) > DSI(HSS+HSA+HSE+HBP) to guarantee that the FIFO
> * is empty before we start a receiving a new line on the DPI
> * interface.
> */
> - if ((u64)dphy_cfg->lane_bps * dpi_hfp * nlanes <
> + if ((u64)dphy_cfg->lane_bps *
> + mode_to_dpi_hfp(mode, mode_valid_check) * nlanes <
> (u64)dsi_hss_hsa_hse_hbp *
> (mode_valid_check ? mode->clock : mode->crtc_clock) * 1000)
> return -EINVAL;
> @@ -842,7 +889,7 @@ cdns_dsi_bridge_mode_valid(struct drm_bridge *bridge,
> struct cdns_dsi_output *output = &dsi->output;
> struct cdns_dphy_cfg dphy_cfg;
> struct cdns_dsi_cfg dsi_cfg;
> - int bpp, nlanes, ret;
> + int bpp, ret;
>
> /*
> * VFP_DSI should be less than VFP_DPI and VFP_DSI should be at
> @@ -860,11 +907,9 @@ cdns_dsi_bridge_mode_valid(struct drm_bridge *bridge,
> if ((mode->hdisplay * bpp) % 32)
> return MODE_H_ILLEGAL;
>
> - nlanes = output->dev->lanes;
> -
> - ret = cdns_dsi_mode2cfg(dsi, mode, &dsi_cfg, &dphy_cfg, true);
> + ret = cdns_dsi_check_conf(dsi, mode, &dsi_cfg, &dphy_cfg, true);
> if (ret)
> - return MODE_CLOCK_RANGE;
> + return MODE_BAD;
>
> return MODE_OK;
> }
> @@ -990,7 +1035,7 @@ static void cdns_dsi_bridge_enable(struct drm_bridge *bridge)
> bpp = mipi_dsi_pixel_format_to_bpp(output->dev->format);
> nlanes = output->dev->lanes;
>
> - WARN_ON_ONCE(cdns_dsi_mode2cfg(dsi, mode, &dsi_cfg, &dphy_cfg, false));
> + WARN_ON_ONCE(cdns_dsi_check_conf(dsi, mode, &dsi_cfg, &dphy_cfg, false));
>
> cdns_dsi_hs_init(dsi, &dphy_cfg);
> cdns_dsi_init_link(dsi);
--
Paul Kocialkowski, Bootlin
Embedded Linux and kernel engineering