linux-kernel - [PATCH] drm/crtc: Add a helper func to get a registered crtc from its index

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 25 Aug 2015 11:13:51 +0800
From:	Xinliang Liu <xinliang.liu@...aro.org>
To:	airlied@...ux.ie, dri-devel@...ts.freedesktop.org
Cc:	linux-kernel@...r.kernel.org, benjamin.gaignard@...aro.org,
	liguozhu@...ilicon.com, kong.kongxinwei@...ilicon.com,
	Xinliang Liu <xinliang.liu@...aro.org>
Subject: [PATCH] drm/crtc: Add a helper func to get a registered crtc from its index

This patch add a helper func to get a registered crtc from its index.
In some case, where we know the crtc's index and we want to know the
crtc too.

For example, the enable_vblank func of struct drm_driver:
In the implementation of this func, we know the index of the crtc but
we want to know the crtc. This helper func can get the crtc easily.
A sample impelmentation of enable_vblank is as shown as bellow:

int hisi_drm_crtc_enable_vblank(struct drm_device *dev, int c)
{
	struct drm_crtc *crtc = drm_get_crtc_from_index(dev, c);
	struct hisi_crtc *hcrtc = to_hisi_crtc(crtc);
	struct hisi_crtc_ops *ops = hcrtc->ops;
	int ret = 0;

	if (ops->enable_vblank)
		ret = ops->enable_vblank(hcrtc);

	return ret;
}

Signed-off-by: Xinliang Liu <xinliang.liu@...aro.org>
---
 drivers/gpu/drm/drm_crtc.c | 25 +++++++++++++++++++++++++
 include/drm/drm_crtc.h     |  2 ++
 2 files changed, 27 insertions(+)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index b9ba061..8764765 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -747,6 +747,31 @@ unsigned int drm_crtc_index(struct drm_crtc *crtc)
 }
 EXPORT_SYMBOL(drm_crtc_index);
 
+/**
+ * drm_get_crtc_from_index - find a registered CRTC from the index
+ * @dev: DRM device
+ * @index: index of a registered CRTC
+ *
+ * Given a index, return the registered CRTC within a DRM
+ * device's list of CRTCs.
+ */
+struct drm_crtc *drm_get_crtc_from_index(struct drm_device *dev,
+					 unsigned int index)
+{
+	unsigned int index_tmp = 0;
+	struct drm_crtc *crtc;
+
+	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+		if (index_tmp == index)
+			return crtc;
+
+		index_tmp++;
+	}
+
+	BUG();
+}
+EXPORT_SYMBOL(drm_get_crtc_from_index);
+
 /*
  * drm_mode_remove - remove and free a mode
  * @connector: connector list to modify
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 57ca8cc..3a46d39d 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -1225,6 +1225,8 @@ extern int drm_crtc_init_with_planes(struct drm_device *dev,
 				     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);
+extern struct drm_crtc *drm_get_crtc_from_index(struct drm_device *dev,
+						unsigned int index);
 
 /**
  * drm_crtc_mask - find the mask of a registered CRTC
-- 
1.9.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/