1 files changed, 466 insertions, 0 deletions

diff --git a/backend/drm/drm.c b/backend/drm/drm.c
new file mode 100644
index 00000000..bb6359c5
--- /dev/null
+++ b/backend/drm/drm.c
@@ -0,0 +1,466 @@
+#include "otd.h"
+#include "drm.h"
+#include "event.h"
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <inttypes.h>
+#include <errno.h>
+#include <xf86drm.h>
+#include <xf86drmMode.h>
+#include <drm_mode.h>
+#include <EGL/egl.h>
+#include <EGL/eglext.h>
+#include <gbm.h>
+#include <GLES3/gl3.h>
+
+static const char *conn_name[] = {
+	[DRM_MODE_CONNECTOR_Unknown]     = "Unknown",
+	[DRM_MODE_CONNECTOR_VGA]         = "VGA",
+	[DRM_MODE_CONNECTOR_DVII]        = "DVI-I",
+	[DRM_MODE_CONNECTOR_DVID]        = "DVI-D",
+	[DRM_MODE_CONNECTOR_DVIA]        = "DVI-A",
+	[DRM_MODE_CONNECTOR_Composite]   = "Composite",
+	[DRM_MODE_CONNECTOR_SVIDEO]      = "SVIDEO",
+	[DRM_MODE_CONNECTOR_LVDS]        = "LVDS",
+	[DRM_MODE_CONNECTOR_Component]   = "Component",
+	[DRM_MODE_CONNECTOR_9PinDIN]     = "DIN",
+	[DRM_MODE_CONNECTOR_DisplayPort] = "DP",
+	[DRM_MODE_CONNECTOR_HDMIA]       = "HDMI-A",
+	[DRM_MODE_CONNECTOR_HDMIB]       = "HDMI-B",
+	[DRM_MODE_CONNECTOR_TV]          = "TV",
+	[DRM_MODE_CONNECTOR_eDP]         = "eDP",
+	[DRM_MODE_CONNECTOR_VIRTUAL]     = "Virtual",
+	[DRM_MODE_CONNECTOR_DSI]         = "DSI",
+};
+
+// EGL extensions
+PFNEGLGETPLATFORMDISPLAYEXTPROC get_platform_display;
+PFNEGLCREATEPLATFORMWINDOWSURFACEEXTPROC create_platform_window_surface;
+
+static bool egl_exts()
+{
+	get_platform_display = (PFNEGLGETPLATFORMDISPLAYEXTPROC)
+		eglGetProcAddress("eglGetPlatformDisplayEXT");
+
+	create_platform_window_surface = (PFNEGLCREATEPLATFORMWINDOWSURFACEEXTPROC)
+		eglGetProcAddress("eglCreatePlatformWindowSurfaceEXT");
+
+	return get_platform_display && create_platform_window_surface;
+}
+
+bool egl_get_config(EGLDisplay disp, EGLConfig *out)
+{
+	EGLint count = 0, matched = 0, ret;
+
+	ret = eglGetConfigs(disp, NULL, 0, &count);
+	if (ret == EGL_FALSE || count == 0) {
+		return false;
+	}
+
+	EGLConfig configs[count];
+
+	ret = eglChooseConfig(disp, NULL, configs, count, &matched);
+	if (ret == EGL_FALSE) {
+		return false;
+	}
+
+	for (int i = 0; i < matched; ++i) {
+		EGLint gbm_format;
+
+		if (!eglGetConfigAttrib(disp,
+					configs[i],
+					EGL_NATIVE_VISUAL_ID,
+					&gbm_format))
+			continue;
+
+		if (gbm_format == GBM_FORMAT_XRGB8888) {
+			*out = configs[i];
+			return true;
+		}
+	}
+
+	return false;
+}
+
+bool init_renderer(struct otd *otd)
+{
+	if (!egl_exts()) {
+		fprintf(stderr, "Could not get EGL extensions\n");
+		return false;
+	}
+
+	otd->gbm = gbm_create_device(otd->fd);
+	if (!otd->gbm) {
+		fprintf(stderr, "Could not create gbm device: %s\n", strerror(errno));
+		return false;
+	}
+
+	if (eglBindAPI(EGL_OPENGL_ES_API) == EGL_FALSE) {
+		fprintf(stderr, "Could not bind GLES3 API\n");
+		goto error_gbm;
+	}
+
+	otd->egl.disp = get_platform_display(EGL_PLATFORM_GBM_MESA, otd->gbm, NULL);
+	if (otd->egl.disp == EGL_NO_DISPLAY) {
+		fprintf(stderr, "Could not create EGL display\n");
+		goto error_gbm;
+	}
+
+	if (eglInitialize(otd->egl.disp, NULL, NULL) == EGL_FALSE) {
+		fprintf(stderr, "Could not initalise EGL\n");
+		goto error_egl;
+	}
+
+	if (!egl_get_config(otd->egl.disp, &otd->egl.conf)) {
+		fprintf(stderr, "Could not get EGL config\n");
+		goto error_egl;
+	}
+
+	static const EGLint attribs[] = {EGL_CONTEXT_CLIENT_VERSION, 3, EGL_NONE};
+	otd->egl.context = eglCreateContext(otd->egl.disp, otd->egl.conf, EGL_NO_CONTEXT, attribs);
+	if (otd->egl.context == EGL_NO_CONTEXT) {
+		fprintf(stderr, "Could not create EGL context\n");
+		goto error_egl;
+	}
+
+	return true;
+
+error_egl:
+	eglTerminate(otd->egl.disp);
+	eglReleaseThread();
+	eglMakeCurrent(EGL_NO_DISPLAY, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
+
+error_gbm:
+	gbm_device_destroy(otd->gbm);
+
+	return false;
+}
+
+void destroy_renderer(struct otd *otd)
+{
+	if (!otd)
+		return;
+
+	eglDestroyContext(otd->egl.disp, otd->egl.context);
+	eglTerminate(otd->egl.disp);
+	eglReleaseThread();
+	eglMakeCurrent(EGL_NO_DISPLAY, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
+
+	gbm_device_destroy(otd->gbm);
+}
+
+void scan_connectors(struct otd *otd)
+{
+	drmModeRes *res = drmModeGetResources(otd->fd);
+	if (!res)
+		return;
+
+	// I don't know if this needs to be allocated with realloc like this,
+	// as it may not even be possible for the number of connectors to change.
+	// I'll just have to see how DisplayPort MST works with DRM.
+	if ((size_t)res->count_connectors > otd->display_len) {
+		struct otd_display *new = realloc(otd->displays, sizeof *new * res->count_connectors);
+		if (!new)
+			goto error;
+
+		for (int i = otd->display_len; i < res->count_connectors; ++i) {
+			new[i] = (struct otd_display) {
+				.state = OTD_DISP_INVALID,
+				.otd = otd,
+			};
+		}
+
+		otd->display_len = res->count_connectors;
+		otd->displays = new;
+	}
+
+	for (int i = 0; i < res->count_connectors; ++i) {
+		struct otd_display *disp = &otd->displays[i];
+		drmModeConnector *conn = drmModeGetConnector(otd->fd, res->connectors[i]);
+		if (!conn)
+			continue;
+
+		if (otd->displays[i].state == OTD_DISP_INVALID) {
+			disp->state = OTD_DISP_DISCONNECTED;
+			disp->connector = res->connectors[i];
+			snprintf(disp->name, sizeof disp->name, "%s-%"PRIu32,
+				 conn_name[conn->connector_type],
+				 conn->connector_type_id);
+		}
+
+		if (disp->state == OTD_DISP_DISCONNECTED &&
+		    conn->connection == DRM_MODE_CONNECTED) {
+			disp->state = OTD_DISP_NEEDS_MODESET;
+			event_add(otd, disp, OTD_EV_DISPLAY_ADD);
+
+		} else if (disp->state == OTD_DISP_CONNECTED &&
+		    conn->connection != DRM_MODE_CONNECTED) {
+			disp->state = OTD_DISP_DISCONNECTED;
+			event_add(otd, disp, OTD_EV_DISPLAY_REM);
+		}
+
+		drmModeFreeConnector(conn);
+	}
+
+error:
+	drmModeFreeResources(res);
+}
+
+static void free_fb(struct gbm_bo *bo, void *data)
+{
+	uint32_t *id = data;
+
+	if (id && *id)
+		drmModeRmFB(gbm_bo_get_fd(bo), *id);
+
+	free(id);
+}
+
+static uint32_t get_fb_for_bo(int fd, struct gbm_bo *bo)
+{
+	uint32_t *id = gbm_bo_get_user_data(bo);
+
+	if (id)
+		return *id;
+
+	id = calloc(1, sizeof *id);
+	if (!id)
+		return 0;
+
+	drmModeAddFB(fd, gbm_bo_get_width(bo), gbm_bo_get_height(bo), 24, 32,
+		     gbm_bo_get_stride(bo), gbm_bo_get_handle(bo).u32, id);
+
+	gbm_bo_set_user_data(bo, id, free_fb);
+
+	return *id;
+}
+
+static void init_display_renderer(struct otd *otd, struct otd_display *disp)
+{
+	disp->gbm = gbm_surface_create(otd->gbm,
+				       disp->width, disp->height,
+				       GBM_FORMAT_XRGB8888,
+				       GBM_BO_USE_SCANOUT | GBM_BO_USE_RENDERING);
+	if (!disp->gbm)
+		return;
+
+	disp->egl = create_platform_window_surface(otd->egl.disp, otd->egl.conf,
+						   disp->gbm, NULL);
+	if (disp->egl == EGL_NO_SURFACE)
+		return;
+
+	// Render black frame
+
+	eglMakeCurrent(otd->egl.disp, disp->egl, disp->egl, otd->egl.context);
+
+	glViewport(0, 0, disp->width, disp->height);
+	glClearColor(0.0, 0.0, 0.0, 1.0);
+	glClear(GL_COLOR_BUFFER_BIT);
+
+	eglSwapBuffers(otd->egl.disp, disp->egl);
+
+	struct gbm_bo *bo = gbm_surface_lock_front_buffer(disp->gbm);
+	uint32_t fb_id = get_fb_for_bo(otd->fd, bo);
+
+	drmModeSetCrtc(otd->fd, disp->crtc, fb_id, 0, 0,
+		       &disp->connector, 1, disp->active_mode);
+	drmModePageFlip(otd->fd, disp->crtc, fb_id, DRM_MODE_PAGE_FLIP_EVENT, disp);
+
+	gbm_surface_release_buffer(disp->gbm, bo);
+}
+
+static drmModeModeInfo *select_mode(size_t num_modes,
+				    drmModeModeInfo modes[static num_modes],
+				    drmModeCrtc *old_crtc,
+				    const char *str)
+{
+	if (strcmp(str, "preferred") == 0)
+		return &modes[0];
+
+	if (strcmp(str, "current") == 0) {
+		if (!old_crtc) {
+			fprintf(stderr, "Display does not have currently configured mode\n");
+			return NULL;
+		}
+
+		for (size_t i = 0; i < num_modes; ++i) {
+			if (memcmp(&modes[i], &old_crtc->mode, sizeof modes[0]) == 0)
+				return &modes[i];
+		}
+
+		// We should never get here
+		assert(0);
+	}
+
+	unsigned width = 0;
+	unsigned height = 0;
+	unsigned rate = 0;
+	int ret;
+
+	if ((ret = sscanf(str, "%ux%u@%u", &width, &height, &rate)) != 2 && ret != 3) {
+		fprintf(stderr, "Invalid modesetting string\n");
+		return NULL;
+	}
+
+	for (size_t i = 0; i < num_modes; ++i) {
+		if (modes[i].hdisplay == width &&
+		    modes[i].vdisplay == height &&
+		    (!rate || modes[i].vrefresh == rate))
+			return &modes[i];
+	}
+
+	return NULL;
+}
+
+bool modeset_str(struct otd *otd, struct otd_display *disp, const char *str)
+{
+	drmModeConnector *conn = drmModeGetConnector(otd->fd, disp->connector);
+	if (!conn || conn->connection != DRM_MODE_CONNECTED || conn->count_modes == 0)
+		goto error;
+
+	disp->num_modes = conn->count_modes;
+	disp->modes = malloc(sizeof *disp->modes * disp->num_modes);
+	if (!disp->modes)
+		goto error;
+	memcpy(disp->modes, conn->modes, sizeof *disp->modes * disp->num_modes);
+
+	drmModeEncoder *curr_enc = drmModeGetEncoder(otd->fd, conn->encoder_id);
+	if (curr_enc) {
+		disp->old_crtc = drmModeGetCrtc(otd->fd, curr_enc->crtc_id);
+		free(curr_enc);
+	}
+
+	disp->active_mode = select_mode(disp->num_modes, disp->modes, disp->old_crtc, str);
+	if (!disp->active_mode) {
+		fprintf(stderr, "Could not find mode '%s' for %s\n", str, disp->name);
+		goto error;
+	}
+
+	fprintf(stderr, "Configuring %s with mode %ux%u@%u\n",
+		disp->name, disp->active_mode->hdisplay, disp->active_mode->vdisplay,
+		disp->active_mode->vrefresh);
+
+	drmModeRes *res = drmModeGetResources(otd->fd);
+	if (!res)
+		goto error;
+
+	bool success = false;
+	for (int i = 0; !success && i < conn->count_encoders; ++i) {
+		drmModeEncoder *enc = drmModeGetEncoder(otd->fd, conn->encoders[i]);
+		if (!enc)
+			continue;
+
+		for (int j = 0; j < res->count_crtcs; ++j) {
+			if ((enc->possible_crtcs & (1 << j)) == 0)
+				continue;
+
+			if ((otd->taken_crtcs & (1 << j)) == 0) {
+				otd->taken_crtcs |= 1 << j;
+				disp->crtc = res->crtcs[j];
+
+				success = true;
+				break;
+			}
+		}
+
+		drmModeFreeEncoder(enc);
+	}
+
+	drmModeFreeResources(res);
+
+	if (!success)
+		goto error;
+
+	disp->state = OTD_DISP_CONNECTED;
+	drmModeFreeConnector(conn);
+
+	disp->width = disp->active_mode->hdisplay;
+	disp->height = disp->active_mode->vdisplay;
+
+	init_display_renderer(otd, disp);
+
+	return true;
+error:
+	disp->state = OTD_DISP_DISCONNECTED;
+	drmModeFreeConnector(conn);
+
+	event_add(otd, disp, OTD_EV_DISPLAY_REM);
+
+	return false;
+}
+
+
+void page_flip_handler(int fd,
+		       unsigned seq,
+		       unsigned tv_sec,
+		       unsigned tv_usec,
+		       void *user)
+{
+	struct otd_display *disp = user;
+
+	disp->pageflip_pending = true;
+	if (!disp->cleanup)
+		event_add(disp->otd, disp, OTD_EV_RENDER);
+}
+
+void destroy_display_renderer(struct otd *otd, struct otd_display *disp)
+{
+	if (!otd || !disp || disp->state != OTD_DISP_CONNECTED)
+		return;
+
+	drmModeCrtc *crtc = disp->old_crtc;
+	if (crtc) {
+		drmEventContext event = {
+			.version = DRM_EVENT_CONTEXT_VERSION,
+			.page_flip_handler = page_flip_handler,
+		};
+
+		disp->cleanup = true;
+		while (disp->pageflip_pending)
+			drmHandleEvent(otd->fd, &event);
+
+		drmModeSetCrtc(otd->fd, crtc->crtc_id, crtc->buffer_id,
+			       crtc->x, crtc->y, &disp->connector,
+			       1, &crtc->mode);
+		drmModeFreeCrtc(crtc);
+	}
+
+	eglDestroySurface(otd->egl.disp, disp->egl);
+	gbm_surface_destroy(disp->gbm);
+
+	free(disp->modes);
+}
+
+void get_drm_event(struct otd *otd)
+{
+	drmEventContext event = {
+		.version = DRM_EVENT_CONTEXT_VERSION,
+		.page_flip_handler = page_flip_handler,
+	};
+
+	drmHandleEvent(otd->fd, &event);
+}
+
+void rendering_begin(struct otd_display *disp)
+{
+	struct otd *otd = disp->otd;
+	eglMakeCurrent(otd->egl.disp, disp->egl, disp->egl, otd->egl.context);
+}
+
+void rendering_end(struct otd_display *disp)
+{
+	struct otd *otd = disp->otd;
+	eglSwapBuffers(otd->egl.disp, disp->egl);
+
+	struct gbm_bo *bo = gbm_surface_lock_front_buffer(disp->gbm);
+	uint32_t fb_id = get_fb_for_bo(otd->fd, bo);
+
+	drmModePageFlip(otd->fd, disp->crtc, fb_id, DRM_MODE_PAGE_FLIP_EVENT, disp);
+
+	gbm_surface_release_buffer(disp->gbm, bo);
+
+	disp->pageflip_pending = false;
+}