drm: omapdrm: Check the CRTC software state at enable/disable time

The omapdrm DSS manager enable/disable operations check the DSS manager
state to avoid double enabling/disabling. Check the CRTC software state
instead to decrease the dependency of the DRM layer to the DSS layer.
The dispc_mgr_is_enabled() function then be turned into a static
function, but needs to be moved up in its compilation unit to avoid a
forward declaration.

Add a WARN_ON to catch double enable or disable that should be prevented
by the DRM core and would be a clear sign of a bug. The warning should
eventually be removed.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

1 files changed, 13 insertions, 14 deletions

diff --git a/drivers/gpu/drm/omapdrm/dss/dispc.c b/drivers/gpu/drm/omapdrm/dss/dispc.c
index c839f6456db2..5554b72cf56a 100644
--- a/drivers/gpu/drm/omapdrm/dss/dispc.c
+++ b/drivers/gpu/drm/omapdrm/dss/dispc.c
@@ -620,6 +620,19 @@ u32 dispc_wb_get_framedone_irq(void)
 	return DISPC_IRQ_FRAMEDONEWB;
 }
 
+void dispc_mgr_enable(enum omap_channel channel, bool enable)
+{
+	mgr_fld_write(channel, DISPC_MGR_FLD_ENABLE, enable);
+	/* flush posted write */
+	mgr_fld_read(channel, DISPC_MGR_FLD_ENABLE);
+}
+EXPORT_SYMBOL(dispc_mgr_enable);
+
+static bool dispc_mgr_is_enabled(enum omap_channel channel)
+{
+	return !!mgr_fld_read(channel, DISPC_MGR_FLD_ENABLE);
+}
+
 bool dispc_mgr_go_busy(enum omap_channel channel)
 {
 	return mgr_fld_read(channel, DISPC_MGR_FLD_GO) == 1;
@@ -2901,20 +2914,6 @@ enum omap_dss_output_id dispc_mgr_get_supported_outputs(enum omap_channel channe
 }
 EXPORT_SYMBOL(dispc_mgr_get_supported_outputs);
 
-void dispc_mgr_enable(enum omap_channel channel, bool enable)
-{
-	mgr_fld_write(channel, DISPC_MGR_FLD_ENABLE, enable);
-	/* flush posted write */
-	mgr_fld_read(channel, DISPC_MGR_FLD_ENABLE);
-}
-EXPORT_SYMBOL(dispc_mgr_enable);
-
-bool dispc_mgr_is_enabled(enum omap_channel channel)
-{
-	return !!mgr_fld_read(channel, DISPC_MGR_FLD_ENABLE);
-}
-EXPORT_SYMBOL(dispc_mgr_is_enabled);
-
 void dispc_wb_enable(bool enable)
 {
 	dispc_ovl_enable(OMAP_DSS_WB, enable);