drm/i915/icl: Set max return packet size for DSI panel

This patch programs maximum size of the payload transmitted
from peripheral back to the host processor using short packet
as a part of panel programming.

v2: Rebase

v3 by Jani:
 - Add FIXME note.

Signed-off-by: Madhav Chauhan <madhav.chauhan@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/ed9df910326adf32eb2bc1cd1a5097d0dda94da8.1540900289.git.jani.nikula@intel.com

diff --git a/drivers/gpu/drm/i915/icl_dsi.c b/drivers/gpu/drm/i915/icl_dsi.c
index 216a175..9c424ad 100644 (file)
--- a/drivers/gpu/drm/i915/icl_dsi.c
+++ b/drivers/gpu/drm/i915/icl_dsi.c
@@ -25,6 +25,7 @@
  *   Jani Nikula <jani.nikula@intel.com>
  */
 
+#include <drm/drm_mipi_dsi.h>
 #include "intel_dsi.h"
 
 static enum transcoder dsi_port_to_transcoder(enum port port)
@@ -636,6 +637,35 @@ gen11_dsi_enable_port_and_phy(struct intel_encoder *encoder,
        gen11_dsi_configure_transcoder(encoder, pipe_config);
 }
 
+static void gen11_dsi_powerup_panel(struct intel_encoder *encoder)
+{
+       struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
+       struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
+       struct mipi_dsi_device *dsi;
+       enum port port;
+       enum transcoder dsi_trans;
+       u32 tmp;
+       int ret;
+
+       /* set maximum return packet size */
+       for_each_dsi_port(port, intel_dsi->ports) {
+               dsi_trans = dsi_port_to_transcoder(port);
+
+               /*
+                * FIXME: This uses the number of DW's currently in the payload
+                * receive queue. This is probably not what we want here.
+                */
+               tmp = I915_READ(DSI_CMD_RXCTL(dsi_trans));
+               tmp &= NUMBER_RX_PLOAD_DW_MASK;
+               /* multiply "Number Rx Payload DW" by 4 to get max value */
+               tmp = tmp * 4;
+               dsi = intel_dsi->dsi_hosts[port]->device;
+               ret = mipi_dsi_set_maximum_return_packet_size(dsi, tmp);
+               if (ret < 0)
+                       DRM_ERROR("error setting max return pkt size%d\n", tmp);
+       }
+}
+
 static void __attribute__((unused))
 gen11_dsi_pre_enable(struct intel_encoder *encoder,
                     const struct intel_crtc_state *pipe_config,
@@ -650,6 +680,9 @@ gen11_dsi_pre_enable(struct intel_encoder *encoder,
        /* step4: enable DSI port and DPHY */
        gen11_dsi_enable_port_and_phy(encoder, pipe_config);
 
+       /* step5: program and powerup panel */
+       gen11_dsi_powerup_panel(encoder);
+
        /* step6c: configure transcoder timings */
        gen11_dsi_set_transcoder_timings(encoder, pipe_config);