drm: provide a helper for the encoder possible_crtcs mask

The encoder possible_crtcs mask identifies which CRTCs can be bound to
a particular encoder.  Each bit from bit 0 defines an index in the list
of CRTCs held in the DRM mode_config crtc_list.  Rather than having
drivers trying to track the position of their CRTCs in the list, expose
the code which already exists for calculating the appropriate mask bit
for a CRTC.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
[treding@nvidia.com: add drm_crtc_index(), move to core]
Signed-off-by: Thierry Reding <treding@nvidia.com>

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index d6cf77c472e710cf246193dca874bd3b8bc72b9e..452bcbd0eab97dd7801a172a8969119e26ae47b5 100644 (file)
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -674,6 +674,29 @@ void drm_crtc_cleanup(struct drm_crtc *crtc)
 }
 EXPORT_SYMBOL(drm_crtc_cleanup);
 
+/**
+ * drm_crtc_index - find the index of a registered CRTC
+ * @crtc: CRTC to find index for
+ *
+ * Given a registered CRTC, return the index of that CRTC within a DRM
+ * device's list of CRTCs.
+ */
+unsigned int drm_crtc_index(struct drm_crtc *crtc)
+{
+       unsigned int index = 0;
+       struct drm_crtc *tmp;
+
+       list_for_each_entry(tmp, &crtc->dev->mode_config.crtc_list, head) {
+               if (tmp == crtc)
+                       return index;
+
+               index++;
+       }
+
+       BUG();
+}
+EXPORT_SYMBOL(drm_crtc_index);
+
 /**
  * drm_mode_probed_add - add a mode to a connector's probed mode list
  * @connector: connector the new mode

diff --git a/drivers/gpu/drm/drm_crtc_helper.c b/drivers/gpu/drm/drm_crtc_helper.c
index 01361aba033b4a39888a41bc15c4a7f5e4052152..940c678cf012acfdeb4311fc202aac1ee44d6c07 100644 (file)
--- a/drivers/gpu/drm/drm_crtc_helper.c
+++ b/drivers/gpu/drm/drm_crtc_helper.c
@@ -334,23 +334,7 @@ EXPORT_SYMBOL(drm_helper_disable_unused_functions);
 static bool drm_encoder_crtc_ok(struct drm_encoder *encoder,
                                struct drm_crtc *crtc)
 {
-       struct drm_device *dev;
-       struct drm_crtc *tmp;
-       int crtc_mask = 1;
-
-       WARN(!crtc, "checking null crtc?\n");
-
-       dev = crtc->dev;
-
-       list_for_each_entry(tmp, &dev->mode_config.crtc_list, head) {
-               if (tmp == crtc)
-                       break;
-               crtc_mask <<= 1;
-       }
-
-       if (encoder->possible_crtcs & crtc_mask)
-               return true;
-       return false;
+       return !!(encoder->possible_crtcs & drm_crtc_mask(crtc));
 }
 
 /*

diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index f32c5cd51f4125a455a81ff60cd190c1383d31e1..4f2e3e82f014ef22cedf10f7b92b543e43a34035 100644 (file)
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -929,6 +929,19 @@ extern int drm_crtc_init(struct drm_device *dev,
                         struct drm_crtc *crtc,
                         const struct drm_crtc_funcs *funcs);
 extern void drm_crtc_cleanup(struct drm_crtc *crtc);
+extern unsigned int drm_crtc_index(struct drm_crtc *crtc);
+
+/**
+ * drm_crtc_mask - find the mask of a registered CRTC
+ * @crtc: CRTC to find mask for
+ *
+ * Given a registered CRTC, return the mask bit of that CRTC for an
+ * encoder's possible_crtcs field.
+ */
+static inline uint32_t drm_crtc_mask(struct drm_crtc *crtc)
+{
+       return 1 << drm_crtc_index(crtc);
+}
 
 extern void drm_connector_ida_init(void);
 extern void drm_connector_ida_destroy(void);