cam: Add DRM helper classes

To prepare for viewfinder operation through the DRM/KMS API, add a set
of helper classes that encapsulate the libdrm functions.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

1 files changed, 331 insertions, 0 deletions

diff --git a/src/cam/drm.h b/src/cam/drm.h
new file mode 100644
index 00000000..ee230402
--- /dev/null
+++ b/src/cam/drm.h
@@ -0,0 +1,331 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2021, Ideas on Board Oy
+ *
+ * drm.h - DRM/KMS Helpers
+ */
+#ifndef __CAM_DRM_H__
+#define __CAM_DRM_H__
+
+#include <list>
+#include <map>
+#include <memory>
+#include <string>
+#include <vector>
+
+#include <libcamera/base/signal.h>
+#include <libcamera/base/span.h>
+
+#include <libdrm/drm.h>
+#include <xf86drm.h>
+#include <xf86drmMode.h>
+
+namespace libcamera {
+class FrameBuffer;
+class PixelFormat;
+class Size;
+} /* namespace libcamera */
+
+namespace DRM {
+
+class Device;
+class Plane;
+class Property;
+class PropertyValue;
+
+class Object
+{
+public:
+	enum Type {
+		TypeCrtc = DRM_MODE_OBJECT_CRTC,
+		TypeConnector = DRM_MODE_OBJECT_CONNECTOR,
+		TypeEncoder = DRM_MODE_OBJECT_ENCODER,
+		TypeMode = DRM_MODE_OBJECT_MODE,
+		TypeProperty = DRM_MODE_OBJECT_PROPERTY,
+		TypeFb = DRM_MODE_OBJECT_FB,
+		TypeBlob = DRM_MODE_OBJECT_BLOB,
+		TypePlane = DRM_MODE_OBJECT_PLANE,
+		TypeAny = DRM_MODE_OBJECT_ANY,
+	};
+
+	Object(Device *dev, uint32_t id, Type type);
+	virtual ~Object();
+
+	Device *device() const { return dev_; }
+	uint32_t id() const { return id_; }
+	Type type() const { return type_; }
+
+	const Property *property(const std::string &name) const;
+	const PropertyValue *propertyValue(const std::string &name) const;
+	const std::vector<PropertyValue> &properties() const { return properties_; }
+
+protected:
+	virtual int setup()
+	{
+		return 0;
+	}
+
+	uint32_t id_;
+
+private:
+	friend Device;
+
+	Device *dev_;
+	Type type_;
+	std::vector<PropertyValue> properties_;
+};
+
+class Property : public Object
+{
+public:
+	enum Type {
+		TypeUnknown = 0,
+		TypeRange,
+		TypeEnum,
+		TypeBlob,
+		TypeBitmask,
+		TypeObject,
+		TypeSignedRange,
+	};
+
+	Property(Device *dev, drmModePropertyRes *property);
+
+	Type type() const { return type_; }
+	const std::string &name() const { return name_; }
+
+	bool isImmutable() const { return flags_ & DRM_MODE_PROP_IMMUTABLE; }
+
+	const std::vector<uint64_t> values() const { return values_; }
+	const std::map<uint32_t, std::string> &enums() const { return enums_; }
+	const std::vector<uint32_t> blobs() const { return blobs_; }
+
+private:
+	Type type_;
+	std::string name_;
+	uint32_t flags_;
+	std::vector<uint64_t> values_;
+	std::map<uint32_t, std::string> enums_;
+	std::vector<uint32_t> blobs_;
+};
+
+class PropertyValue
+{
+public:
+	PropertyValue(uint32_t id, uint64_t value)
+		: id_(id), value_(value)
+	{
+	}
+
+	uint32_t id() const { return id_; }
+	uint32_t value() const { return value_; }
+
+private:
+	uint32_t id_;
+	uint64_t value_;
+};
+
+class Blob : public Object
+{
+public:
+	Blob(Device *dev, const libcamera::Span<const uint8_t> &data);
+	~Blob();
+
+	bool isValid() const { return id() != 0; }
+};
+
+class Mode : public drmModeModeInfo
+{
+public:
+	Mode(const drmModeModeInfo &mode);
+
+	std::unique_ptr<Blob> toBlob(Device *dev) const;
+};
+
+class Crtc : public Object
+{
+public:
+	Crtc(Device *dev, const drmModeCrtc *crtc, unsigned int index);
+
+	unsigned int index() const { return index_; }
+	const std::vector<const Plane *> &planes() const { return planes_; }
+
+private:
+	friend Device;
+
+	unsigned int index_;
+	std::vector<const Plane *> planes_;
+};
+
+class Encoder : public Object
+{
+public:
+	Encoder(Device *dev, const drmModeEncoder *encoder);
+
+	uint32_t type() const { return type_; }
+
+	const std::vector<const Crtc *> &possibleCrtcs() const { return possibleCrtcs_; }
+
+private:
+	uint32_t type_;
+	std::vector<const Crtc *> possibleCrtcs_;
+};
+
+class Connector : public Object
+{
+public:
+	enum Status {
+		Connected,
+		Disconnected,
+		Unknown,
+	};
+
+	Connector(Device *dev, const drmModeConnector *connector);
+
+	uint32_t type() const { return type_; }
+	const std::string &name() const { return name_; }
+
+	Status status() const { return status_; }
+
+	const std::vector<const Encoder *> &encoders() const { return encoders_; }
+	const std::vector<Mode> &modes() const { return modes_; }
+
+private:
+	uint32_t type_;
+	std::string name_;
+	Status status_;
+	std::vector<const Encoder *> encoders_;
+	std::vector<Mode> modes_;
+};
+
+class Plane : public Object
+{
+public:
+	enum Type {
+		TypeOverlay,
+		TypePrimary,
+		TypeCursor,
+	};
+
+	Plane(Device *dev, const drmModePlane *plane);
+
+	Type type() const { return type_; }
+	const std::vector<uint32_t> &formats() const { return formats_; }
+	const std::vector<const Crtc *> &possibleCrtcs() const { return possibleCrtcs_; }
+
+	bool supportsFormat(const libcamera::PixelFormat &format) const;
+
+protected:
+	int setup() override;
+
+private:
+	friend class Device;
+
+	Type type_;
+	std::vector<uint32_t> formats_;
+	std::vector<const Crtc *> possibleCrtcs_;
+	uint32_t possibleCrtcsMask_;
+};
+
+class FrameBuffer : public Object
+{
+public:
+	struct Plane {
+		uint32_t handle;
+	};
+
+	~FrameBuffer();
+
+private:
+	friend class Device;
+
+	FrameBuffer(Device *dev);
+
+	std::vector<Plane> planes_;
+};
+
+class AtomicRequest
+{
+public:
+	enum Flags {
+		FlagAllowModeset = (1 << 0),
+		FlagAsync = (1 << 1),
+	};
+
+	AtomicRequest(Device *dev);
+	~AtomicRequest();
+
+	Device *device() const { return dev_; }
+	bool isValid() const { return valid_; }
+
+	int addProperty(const Object *object, const std::string &property,
+			uint64_t value);
+	int addProperty(const Object *object, const std::string &property,
+			std::unique_ptr<Blob> blob);
+	int commit(unsigned int flags = 0);
+
+private:
+	AtomicRequest(const AtomicRequest &) = delete;
+	AtomicRequest(const AtomicRequest &&) = delete;
+	AtomicRequest &operator=(const AtomicRequest &) = delete;
+	AtomicRequest &operator=(const AtomicRequest &&) = delete;
+
+	int addProperty(uint32_t object, uint32_t property, uint64_t value);
+
+	Device *dev_;
+	bool valid_;
+	drmModeAtomicReq *request_;
+	std::list<std::unique_ptr<Blob>> blobs_;
+};
+
+class Device
+{
+public:
+	Device();
+	~Device();
+
+	int init();
+
+	int fd() const { return fd_; }
+
+	const std::list<Crtc> &crtcs() const { return crtcs_; }
+	const std::list<Encoder> &encoders() const { return encoders_; }
+	const std::list<Connector> &connectors() const { return connectors_; }
+	const std::list<Plane> &planes() const { return planes_; }
+	const std::list<Property> &properties() const { return properties_; }
+
+	const Object *object(uint32_t id);
+
+	std::unique_ptr<FrameBuffer> createFrameBuffer(
+		const libcamera::FrameBuffer &buffer,
+		const libcamera::PixelFormat &format,
+		const libcamera::Size &size, unsigned int stride);
+
+	libcamera::Signal<AtomicRequest *> requestComplete;
+
+private:
+	Device(const Device &) = delete;
+	Device(const Device &&) = delete;
+	Device &operator=(const Device &) = delete;
+	Device &operator=(const Device &&) = delete;
+
+	int getResources();
+
+	void drmEvent();
+	static void pageFlipComplete(int fd, unsigned int sequence,
+				     unsigned int tv_sec, unsigned int tv_usec,
+				     void *user_data);
+
+	int fd_;
+
+	std::list<Crtc> crtcs_;
+	std::list<Encoder> encoders_;
+	std::list<Connector> connectors_;
+	std::list<Plane> planes_;
+	std::list<Property> properties_;
+
+	std::map<uint32_t, Object *> objects_;
+};
+
+} /* namespace DRM */
+
+#endif /* __CAM_DRM_H__ */